Secret Projects FWaTA

BILL ROSE

SECRET PROJECTS

FLYING WINGSAND TAILLESS AIRCRAFT

SECRET PROJECTS

FLYING WINGSAND TAILLESS AIRCRAFT

BILL ROSE

MIDLANDAn imprint of

Ian Allan Publishing

SECRET PROJECTS:

FLYING WINGS AND TAILLESS AIRCRAFT

by Bill Rose

First published 20 I 0

ISBN 9781857803204

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Photograph on half-title page:The first unmarked XB-35 seen as it is towedacross the runway at Northrop's Hawthorne facility.

orthrop Grumman

Photograph on title page:A B-2A strategic bomber of the 509th Bomb Wingin flight. USAF

Contents

Introduction 6

Chapter One British Tailless Aircraft 10

Chapter Two German World War 2 Flying Wing Development 34

Chapter Three US Flying Wings (1935-1950) 70

Chapter Four US Flying Wings (1950-1990) 95

Chapter Five US Manned Tailless Aircraft (1980-2030) 109

Chapter Six Soviet Tailless Designs 130

GlossalY 143

Index 144

Secret Projects: Flying Wings and Tailless Aircraft 5

The flying wing is the purest form in aviation.Millions of years before mankind existed itwas evolved by nature as a simple and efficient way of transporting seeds over considerable distances. When men first nviouslycast their eyes skywards and considered theidea of undertaking flight, birds were the obvious inspiration; however, some pioneersstudied the way that certain trees used thewind to carry aerodynamic seeds to new locations. This would encourage experimentswith flying wing models and large mannedgliders. However, various technical problemsand a resistance to new ideas restrained thedevelopment of powered designs, with relatively slow progress being made until WorldWar 2 when engine performance improveddramatically. The flying wing was then considered for the role of advanced fighters andintercontinental bombers.

Th perfect flying wing is a shape reducedto the bare minimum, with few, if any protuberances, no significant visible fus lage section and the efficient use of internal space.This type of aircraft promises high lift and lowdrag, although stability and handling werechallenges for early designers. Subsequently,many flying wing aircraft were aerodynamiccompromises. The early flying wings requiredvertical stabilisers for effective control, whilefuselage sections spread beyond the wing'sboundaries, and in some cases, engine pods

Introduction

were added. Becau e of this, many so-calledflying wings were more accurately defined as'tailless aircraft' and the wing could be sweptback, swept forward, swivelling in an obliquemanner, traight, of variable geometry, ordelta-shaped.

Typically, the flying wing and closelyrelated configurations are unsuitable fordevelopment as a supersonic aircraftbecause of their large wingspans. Nevertheless, there are some interesting exceptions tothe rule and scope for supersonic performance with certain highly-swept taillessdesigns. That aside, the flying wing is potentially a very efficient aerodynamic configuration for carrying substantial payloads atsubsonic speeds over long distances.

Some historians will rightly attribute theearliest designs for a manned flying wing toLeonardo da Vinci (1452-1519) who produced a detailed drawing of a man-poweredornithopter (flapping wing device) around1485. The de ign was little more than a fanciful idea, but intere t in the possibility ofmanned flight gath red momentum duringthe following centuries, eventually leading toexperiments with balloon and mall handlaunched gliding models.

One particularly interesting idea thatstemmed from a simple paper dart was a flying wing design produced by James WilliamButler and Edmund Edwards in 1867. They

envisaged a scaled-up man-carrying aircraft,powered by some form of steam propulsionand patented the design, although manya pect of the concept were ahead of its time.This was followed by the first demonstrationof sustained flight when Alphonse Penaud(1850-1880) flew a rubber band-poweredmodel for a distance of 131 ft (40m) on 18August 1871 in Paris. Having shown that powered flight was possible, Penaud went on toconceive a series of astonishingly advancedflying wing aircraft that were never flown, butset th standard for all future de igns. Penaudwas succeeded by the aviation pioneer LouisPierre Mouillard (1834-1897) who, it isbelieved, made a short flight of 90ft (27m) atan altitude of 30ft (9m) in his fourth glidernear Cairo, Egypt, on 3 JanualY 1878.

While Otto Lilienthal (1848-1896) is oftencredited with flying the first succes fulmanned glider in 1891, it is widely claimedthat Mouillard and Lilienthal were followingin the foot teps of Engli h inventor Sir GeorgeCayley (1773-1857). He designed and builtseveral gliders, which were reportedly te tedby an unknown 10-year-old boy and Cayley'scoachman on several occasions between1799 and 1853. Whether or not Cayleydeserves to be credited with the first mannedglider flight remains open to debate. Anotherearly pioneer was Igo Etrich (1879-1967) whobuilt gliders based on the winged liana seedand this work proved to be influential to manyfuture designers. The application of an internal combustion engine to a tailless designwas then adopted by pioneers such as Frenchengineer Rene Arnoux and British designerJohn William Dunne (1875-1949).

World War 1saw vast improvements in aviation technology with aircraft becoming avaluable military asset. After ho tilitiesceased in 1918, German engineer HugoJunkers turned his attention towards buildingan efficient aircraft known as the JG-1 that

The German glider pioneer Olio Lilienthalundertaking a short flight at Berlin on anunspecified date in 1896. He experienced manyaccidents during these trials and died as a resultof serious injuries sustained in a crash on 9 August1896. His last words were 'Sacrifices must bemade'. Bill Rose Collection

would seat passengers within the wing.Unfortunately for Junkers, the design wasdeemed to have contravened conditions ofaircraft construction set out by the Allies andthe JG- I was therefore scrapped. Junkers hadpatented a flying wing aircraft in 1910 andwas a trong supporter of this configuration,envisaging future giant transporters capableof carrying 1,000 passengers.

Although such a design never materialised,there would be significant progress made inGermany during the following decades byAlexander Lippisch and the Horten brotherswho were re ponsible for a number of highlysignificant tailles designs. World War 2 sawmajor developments of their work with Lippisch and the Horten designing advanced jetand rocket-powered aircraft that pushedtowards the boundaries of supersonic flight.In North Am rica, the main advocate anddeveloper of the flying wing was Jack (John)Northrop, although it should be noted thatVincent Burnelli (1895-1964), who is oftenoverlooked, made great strides with liftingbody designs.

At one stage during World War 2, Americanstrategists believed that Britain would fall toGermany and Jack orthrop was given thetask of designing a new US Army Air Corpsbomber capable of reaching Europe. Thiproject led to construction of the futuristicB-35 flying wing; however, by the time it flew,the propeller-driven warplane was virtuallyobsolete. The design was re-engin ered intothe jet-powered B-49, but the new Northropaircraft was t chnically flawed and could notcompete with the relatively straightforwardB-47 produced by Boeing. Subsequently, theB-49 never became operational and interestin flying wings sharply declined.

While designers continued to study the flying wing, no significant aircraft of this typewere built for many years, although Britishpost-war interest in tailless aircraft led to thesuccessful delta-wing Avro Vulcan bomber.By the 1970s, advances in computer technology were making the flight control of unusualdesigns a reality and scientists recognised thepotential of the flying wing as an aircraft wilhan exceptionally low radar cross section.

The Burgess-Dunne Flying Wing Biplane of 1914.Bill Rose Collection

'Le Stablavion' (stable aircraft) was built by Frenchconstructor Rene Arnoux and demonstrated to thepublic in 1913. Powered by a 55hp (41 kW) Chenupiston engine, the performance and handling weresaid to be disappointing. Bill Rose Collection

Featuring a pusher configuration, Rene Arnoux'stwo-seat flying wing monoplane was demonstratedin Paris during 1914. Bill Rose Collection

6 Secret Projects: Flying Wings and Tailless Aircraft Secret Projects: Flying Wings and Tailless Aircraft 7

I -..

An illustration of the experimental Northrop N·IMflying wing during a test flight. Bill RoselNorthrop Grumman

The futuristic Vickers Swallow supersonic nuclearstrike aircraft was designed in the 1950s and isshown resplendent in RAF markings and anti-flashwhite finish. The Swallow was too far ahead of itstime to be a realistic proposition.Bill Rose Collection

Northrop Grumman's proposal for the USAF's nextgeneration bomber expected to enter service in2018. Northrop Grumman/Bill Rose Collection

handling problems for civil versions andfew airports could accommodate BWBs atpresent.

Because there are many grey areasbetween true flying wings, tailless aircraft,BWB designs and deltas, I have tried to avoidsetting definite limits on what kind of aircraftare suitable for inclusion in this book. This hasproved to be quite a challenge, as it is oftenunclear where to draw the line despite considerable consultation with colleagues. As anexample, it now appears acceptable todescribe an aircraft in technical papers as a'tailed' flying wing and some authors regarddesigns such as the Mirage or Concorde asbelonging in the flying wing category. Therefore, I have set my own guidelines and haveincluded various interesting tailless aircraftranging from the British World War 2 experimental GAL gliders and the German Me 163rocket fighter to the advanced variable geometry of the Vickers Swallow and exoticoblique wing designs.

This book mainly deals with manned aircraft as the detailed additional coveragerequired for unmanned tailless designswould at least double the space and thereare practical limits in producing such a publication. I have not attempted to write anexhaustive technical appraisal of the flyingwing or tailless design and this book is not adefinitive reference work containing examples of every known design. That said, I havetried to provide background information onmany - often lesser-known - military concepts and designs that have (in a few cases)been built as prototypes and occasionallyreached production.

Many individuals provided assistance withbackground material for this book, but Iwould like to especially thank Chris Gibsonand Tony Buttler, Dr lain Murray, RobertBradley of the San Diego Air & SpaceMuseum, Martin Muller, Alexi Malinovsky andTony Chong of Northrop-Grumman.

Bill Rose, Norfolk, EnglandFebruary 2010

B-49 and Avro Vulcan proved hard to delectwith prevailing ground-based radar syslems.An ability to hide aircraft from enemy delection would have many advanlages and thisresulted in highly classified US research during the 1970s 10 produce a low-visibility combal aeroplane. This eventually resulted in theLockheed F-117A that was developed from adiamond shape, and although it wasdescribed as a fighter, was designed as a specialised subsonic attack aircraft that wasincapable of air-to-air combat. The ability tolaunch a small-scale surprise attack was obvious, but the F-117A was not expected to farewell in a major confrontation with the SovietUnion, whose air defence capabilitiesremained significant and were under constant revision. Therefore, the USAF required anexl-generation bomber with an intercontinental range, a substantial payload capabilityand relative invisibility to all existing andanticipated radar systems. This led to proposals for an advanced bomber that resulted inthe Northrop-Grumman B-2A Spirit making itsfirst flight in 1986. Developed and built in greatsecrecy, the B-2A strategic bomber becameto be the most expensive combat aircraft inhistory, with its eventual use in small regionalconflicts widely regarded as overkill.

Nevertheless, the B-2A remains a technicalmasterpiece and is a true flying wing aircraftin every respect, although its shape wasselected for reasons of low visibility and thesleek appearance was almost a by-product.The US Navy also sought a new carrier-borne,multi-role combat aircraft with a stealth capability and this led to the A-I2AAvenger II, a triangular-shaped flying wing developed byGeneral Dynamics and McDonnell Douglas.In some respects, this aircraft was moreadvanced than the B-2A. However, spirallingdevelopment costs brought the A-I2A programme to an abrupt halt.

A new US manned bomber is currently inits initial development phase and is widelyvisualised as a second-generation B-2. However, the main application for low-observabletechnology at the present time is for increasingly sophisticated remote-control aircraftthat often feature flying wing configurations.Further tailless aircraft seem inevitable asdesigners look towards aerodynamically efficient blended wing body CBWB) configurations to satisfy demands for new tacticalairlifters, tankers and airliners. These aircraftare likely to become a common sight in ourskies during the coming decades. BWBs willnot be capable of higher speeds than existingaircraft in the same class, but will transportgreater payloads over longer ranges at lowercost. On the down side, there may be ground

Fig. I.

Hugo Junker's influential 1910 patent for a newtype of aircraft that would contain its mostimportant features inside the wing.ESP Patent Office

Engineer, aviation pioneer and founder of thefamous aircraft manufacturing concern,Hugo Junkers was an advocate of the flying wingand did much to secure its widespread acceptance.Bill Rose Collection

It had been apparent that flying wings wereharder to detect with radar than conventionalaircraft and this was believed to be a featureof the Horten jet fighter that first flew at theend of World War 2. It is now suggested thatany stealth qualities the Horten jet fighter possessed were more accidental than intentional, even when considering the significantadvances in radar countermeasures made byGerman scientists during the war.

It has been reported on several occasionsthat post-war aircraft such as the Northrop

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Chapter One

Baynes Bat

After leaving chool, Leslie Everett Baynes(1902-1989) became immediately involvedwith lh aviation industry. He worked for lheAircraft Engineering Company in Hendon,

orth London, became a designer for ShortBrothers at Rochester and then d vised thevery succe ful cud I light sailplane. This ledhim into a manufacturing partner hip withF.D. Abbot, forming the company AbbotBaynes Sailplanes Ltd of Farnham, Surrey. In1935, a powered version of the Scud was builtto meet a request made by Sir John Cardenwho ran a company developing armouredvehicles. As a consequence of this order, anew partnership was formed, called CardenBaynes Aircraft, with a factory located at He ton, Middles x wh re powered aircraft weremanufactured. Baynes and Carden began

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controlled machine gun turrets weremounted outboard of the propellers on eachtrailing edge and a single forward firing gunturret was positioned on the leading edge, tothe port side of centre. The control surfacesappear similar to the larger de ign.

These designs were undoubtedly submitted for official consideration, but went no further as they were probably considered far toounconventional. Undeterred, Professor Hillcontinued to work on the concept, which henow envisaged as a large trans-Atlantic airliner suitable for post-war operation Thisproposal was known as the PterodactylMkVlll and was to be powered by five RollsRoyce Griffon engines driving pusher propellers. The airliner was to have a cockpitsection protruding from the central leadingedge. Despite interesl from Short Brothers,nothing came of this project.

A proposed six-engine, three contra-propPterodactyl flying wing bomber, with an estimatedweight of 85,000 Ib (38,555kg). Bill Rose Collection

Professor Hill's wartime proposal for a fourengine, propeller-driven flying \\1ng PterodactylBomber. Bill Rose Collection

also considered and Hill believed this designcould easily be modified when jet propulsionbecam available. Estimates of performanceare not quoted in any available documentation. The Pterodactyl bomber would be supported on a rather unusual fully retractableundercarriage consisting of four larg mainwheels, positioned across the underside ofthe wing at the centre of gravity and a singlenose-wheel. During take-offs and landings,the pilot would sit in a capsule locatedtowards the centre of the aircraft. This wouldbe exlended below the wing to afford thepilot a better view of the runway and it wouldbe possibl to use the front wheel as a positioning aid. For normal night, the pilot wouldsit behind a windshi ld in the leading edge ofthe wing, positioned slightly starboard of centre. Hill also planned to seat the navigatoralongside the pilot at the front of the aircraft,with extra windows allowing downwardobservation.

The bomber would be equipped with fourremote-conlrolled machine gun turrets, alloutboard of the engine bays and propellers.Details of bomb carriage are unknown,although it seems certain that at least twoseparate bays w re envisaged on either sideof the cabin area. There were no vertical control surfaces, although in addition to elevonsand naps, Hill proposed movable wingtips.One development of this design was an aircraft carrier, able to transport up lo thr e piston-engine fighters (presumably Spitfires orHurricanes) on the upp I' wing. This wouldmake il possible to operale at ranges muchgreater than might normally be available. Presumably the fighters would return to baseunder their own power, or the pilot wouldbailout at a pre-arranged location.

Hill also designed a smaller version of thePterodactyl bomber with a wingspan ofapproximately 100ft (30Am) and a length ofabout 38ft (ll.5m). It would have an anticipated weight of approximately 45,0001b(20,411 kg). This design differed in having fourseparate unspecified piston engine , eachdriving a tail-mounted propeller. The fUllyretractable undercarriage would be slightlysimpler than the larger bomber, using threeseparate main wheels and a single nosewheel. It appears that Professor Hill did notconsider th retractable pilot's cap ule necessary for this aircraft. Rear facing remote-

Designed by Geoffrey Hill, the MkV Pterodactylwas a military variant of this pre-war series ofaircraft developed to meet Specification F.3/32.A sesquiplane in configuration with a small,unsweptlower wing, the Pterodactyl MkV was filledwith two forward-firing machine guns and carrieda rear gunner who enjoyed an unrestricted view.Bill Rose Collection

The Pterodactyl BombersIn 1939, Professor Hill was recruited by the AirMinistry to oversee various specialised mililary research projects and his first assignmentinvolved a programme to assess various waysof allowing an aircraft to cut enemy barrageballoons' cables without slalling. In additionlo a range of consultative work, Hill becamethe chief cientific liaison officer between theBritish and Canadian governments in 1942.At the tart of this period, he began a privatedesign project for an advan ed taillessbomber with initial plans being completed on22 July 1942.

Hill's fir t proposal was a boomerangshaped nying wing with a straight c ntralleading edge and the outer wing sectionswept (at the leading edge) by approximately44°. The wingspan was 140ft (42.6m) with awing area of 3,350ft' (311 m') and the overalllength appears to have been around 50ft(15.24m). The wing would have a centraldepth of 7ft 6in (2.28m), making a substantialpressurised crew compartment possible.Quoled weight is 85,0001b (38,555kg) andwas presumably an all-up estimate.

Hill envisaged six forward-posilioned piston engines mounted in side-by- ide pairs,driving three rear-mounted pusher configuration contra-rotating propeller assemblie vialengthy drive shafts. The use of turbojet was

bomb load. The prototype was ready to ny in1933. During tests the performance was saidto b comparable to a Hawker Demon andlongitudinal stability was certainly superior to

arlier Pterodactyl designs. Despite itspromise, the MkV failed to win support for further development. Although disappointed,Hill ontinued to work on the Pterodactyldesign producing further tailless aircraft concepts, but the project was effectively at anend.

British Tailless Aircraft

Cherub engine and new towards the end of1925. In 1926, Hill joined Westland Aircraft,which secured Air Ministry backing for furtherdevelopment of the Pterodactyl design andfiled a patent for a wing adjustment design in1930

A series of small aircraft followed with Hilldesigning a two-s at fighter version of the aircraft for Specification F3/32, known as theMkV. Construction began in 1932 with duralumin and steel being us d for the majority ofthe fuselage framework and main wing.From the outset, Hill decided to add short,unswept lower wings for strengthening purposes, making the MkV a sesquiplane. Theundercarriage consisted of tandem wheelslocated beneath the centre of the fuselageand skids below each lower wingtip withsmall trailing wheels. A very troublesomeROils-Royce Goshawk I engine in a forwardmounted position powered the MkV, providing a maximum speed in level night of around190mph (306kph) and a service ceiling of30,000ft (9,144m). When empty, the MkVweighed 3,5341b (1,602kg) and around5, I 00 lb (2,313kg) when fUlly loaded. Thewingspan was 46ft 8in (14.2m) with a wingarea of 396ft' (36.78m') and the overall lengthwas 20ft 6in (6.24m). As a fighter, the aircraftwould be equipped with several machineguns and was capable of carrying a small

Geoffrey Hill

In late 1942, the K Director of ScientificResearch decided to form the Taille sAircraftAdvisory ommittee (TAAC) to over eedevelopment of new designs. German air-raft designers were known to be int rested

in developing tailless military aircraft andconsiderable research was also taking placin America. orthrop was working on a longrange, nying wing bomber and the ationalAdvisory Committee for Aeronautics (NACAthe forerunner of ASA) was underlakingextensive research into laminar now aerofoils. Therefore, the British hoped to takeadvantage of US developmenls for a future jetpropelled tailless bomber.

Tailless aircraft were nothing new in Britainwith the early pioneering work of JohnWilliam Dunne inspiring more advanceddesigns by Geoffrey Terence Roland Hill(1895-1955). Hill had become preoccupiedwith the problem of stalling and this led himto design the Pterodactyl Mk 1, a nying wingwith a 31 0 leading edge sweep and all-movingwingtips. The aircraft was built during an 18month period with Air Mini try support andn was a glider in December 1924. It was thenequipp d with a 33hp (24.6kW) Bristol

10 Secret Projects: Flying Wings and Tailless Aircraft British Tailless Aircraft II

Mn

Ft 10

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The quite distinctive central fuselage section accommodated a two-man crew withthe flight observer sitting directly behind thepilot and facing rearward. The Manx wasequipped with a tricycle undercarriage withthe rear wheels able to retract, but the nosewheel fixed. This was normally fitted with astreamlined fairing to reduce drag. Taxiing trials began at Radlett in late 1940, althoughtests became long and drawn out, with morepressing wartime work often taking priority.

The company's senior test pilot, JamesRichard Talbot (1909-1945), was nowinvolved with these trials, along with EdgarAlexander 'Ginger' Wright (1914-1945), a Handley Page test pilot who headed theObserver's Office. On 12 September 1942, during high speed taxiing trials, the Manx becamemomentarily airborne, achieving a height ofabout 12ft (3.65m), but after touchdown, itwas evident that the nose-wheel had beendamaged, so repairs and modifications weremade. Further attempts to fly the Manx followed and it finally became airborne on IIJune 1943, with Talbot at the controls. However, the cockpit canopy became detachedsoon after take-off and the flight was immediately terminated. As trials continued on anintermittent basis, the renowned glider pilotRobert Kronfeld was invited to test fly theManx. Kronfeld was now an RAF SquadronLeader, assigned to General Aircraft Ltd (GAL)ofFeltham, Middlesex, which was working onits own experimental tailless glider project.

General arrangement of the taillessHP.75 Manx experimental aircraft.Chris Gibson

found to be substantially overweight andthere were serious problems with the type ofglue used during assembly. As a consequence, the aircraft underwent a programmeof modifications and the main spar waslargely rebuilt. It is possible that this had somebearing on the fact that Dart Aircraft hadceased trading by the end of 1939.

Built mostly from wood, this aircraftreceived the semi-official name Manx (afterthe tailless cat). It has been claimed that thecompany designation HP.75 may not havebeen applied until 1945, although the officialregistration H-0222 was issued at an earlystage in this project. The Manx was fitted withtwo rear-mounted de Havilland Gipsy Major IIfour-cylinder piston engines, each rated at140hp (l04kW) and fitted with two blade propellers acting as pushers. The overallwingspan was 39ft lOin (l2.lm), wing areawas 245ft' (22.76m2

), the length was 18ft 3in(5.5m) and the empty weight was 3,0001b(I ,360kg). Maximum take-offweight was estimated at 4,0001b (I,814kg) allowing a maximum speed of approximately 146mph(234kph) and a service ceiling of about 1012,000ft (3,000-3,650m). The central sectionof the wing on either side of the cockpit wasstraight and the outer section was swept backby 35° with elevons and leading edge slots.An upright fin and rudder was attached toeach wingtip and an additional fin waslocated on the upper rear of the fuselage toenhance flight control.

Melrose 'Winkle' Brown was less enthusiastic about the Baynes BAT when he tested it,finding the controls disappointing.

Why this difference of opinion arose is hardto say, but the tests were still judged success[ul. Unfortunately, there were ongoing problems concerning tank suitability and it hadI> en realised that landing faster than thetank's maximum speed was a serious issue.I'his led to the idea of fitting an undercarriageto the BAT, but it was considered over-compi x and the Baynes BAT was then movedonto the back burner. At the same time, aheavy glider was being developed by Generalo\ircraft called the GAL.49 Hamilcar, whichhad been designed from the outset to carry asubstantial payload that included a Tetrarchor the US-designed M22 Locust light tank.

While the Hamilcar eventually entered service, the Baynes BAT never progressed to ahill-sized carrier wing glider. It was thentransferred to the Royal Aircraft EstablishIII nt at Farnborough, which made good useo[ it for stability tests that continued after thewar. In late 1946, the Baynes BAT was forlI\ally disposed of as surplus equipment,Il(,jng purchased by British Light Aircars ofHl'dhill, Surrey. It seems that the BAT wasthen moved to Croydon Airport where it was1,Ist seen behind a hangar in 1958, apparentlyIII poor condition. Soon after this, the gliderwa scrapped. Baynes, known to his friends<lnd family as 'Baron', worked on many otherinteresting wartime projects that included anIinusual tilt-rotor aircraft design and he wasIl'sponsible for design work on convertingI.ancasters to carry the Barnes Wallis bouncing bomb used to breach several dams in theI{uhr Valley during May 1943.

Handley Page Manx

In the late 1930s, Dr Gustav Victor Lachman(1896-1966), an Austrian scientist whoheaded the Design Office at Handley PageAircraft, turned his attention towards the possibility of improving aircraft performance by asignificant reduction in drag. He favoured theflying wing design and the company chairman, Frederick Handley Page, fully supported this research and agreed to authorisethe construction of a small experimental aircraft. The initial assembly would be contracted out to Dart Aircraft of Dunstable,Bedfordshire, which was a small specialistcompany building gliders and replica light aircraft. Work seemed to proceed well and theairframe was returned to Handley Page atRadlett, Hertfordshire, during September1939, for completion. But the aircraft was

I33ft 4in (I0.15m)22' (leading edge)160ft' (I4.86m')7:111ft 4in (3.45m)7631b (346kg)9631b (437kg)90mph (I45kph)120mph (I93kph)40mph (64kph)

The Baynes BAT during a test flight. This smallglider was designed during World War 2 to test thepossibility of building a much larger 'Carrier Wing'capable of transporting a light tank to a combatzone. Bill Rose Collection

Baynes Bat

Three-view drawing of the Baynes BAT.Bill Rose Collection

CrewWingspanSweepWing areaAspect ratioLengthEmpty weightGross weightCruising speedMaximum speedStalling speed

known as the Tetrarch. This vehicle had acombat weight of 16,800 Ib (7,620kg) and carried a crew of three. The glider's swept wingwould have a 100ft (30m) span with verticalstabilisers at the wingtips. It was proposedthat just before landing the tank's enginewould be started, allowing it to go into actionimmediately after touchdown.

The Baynes BAT received enthusiastic official support and it was decided to build a onethird-scale, proof-of-concept tailless mannedglider, with a wingspan of 33ft 4in (10m) andusing a single main spar. A small cockpitaccommodated the pilot and the undercarriage was composed of a lower centrallylocated skid and wingtip skids. A wheeledtrolley was used for ground handling andtake-offs. A nacelle replaced the areabeneath the glider where the tank would becarried. On the full-sized version, the wingwould be released at the moment of touchdown and drawn away from the tank. A contract was issued to Slingsby Sailplanes atKirkbymoorside for the manufacture of a prototype. Built almost entirely from wood, theglider was completed during spring 1943 andissued with the serial RA809. The first testflight took place in the summer of 1943 at Airborne Forces Experimental Establishment(AFEE), Sherburn-in-Elmet, Yorkshire. WithFit Lt Robert Kronfeld at the controls, theBaynes BAT was towed into the air behind anAvro Tutor.

Kronfeld later reported that, 'In spite of itsunorthodox design the aircraft handles similarly to other light gliders with very light andresponsive controls and is safe to be flown byservice pilots in all normal attitudes of flight.'However, the RAE's chief test pilot Capt Eric

and the army was looking for ways to airliftmilitary cargo and equipment to operationalareas. In 1941, Baynes designed an unpowered 'Carrier Wing' capable of transporting alight tank to a combat zone, which was generally referred to as the Baynes Aerial Tank(BAT).

Taking the form of a towed glider, it wouldtransport a light armoured vehicle, which wasexpected to be the Armstrong WhitworthMkVII Light Tank developed in 1938 and later

producing a sailplane (which was essentiallya Scud 3) equipped with a small retractable249cc Villiers engine. The unit was mountedabove the aircraft in a pusher configurationand a small tank carried enough fuel to runthe engine for about 30 minutes.

At the start of World War 2, Baynes hadbecome a scientific advisor to the Alan MuntzCompany in Heston and he took responsibility for organising its aircraft division. At thistime there were no suitable transport aircraft

12 Secret Projects: Flying Wings and Tailless Aircraft British Tailless Aircraft 13

~I \ '..'\ I.........

Top: The third GAL56 glider 'Maximum V' (TS513),which made its maiden flight on 30 May 1947at Lasham. Bill Rose Collection

Above: Three-view drawing of the GAL56'Medium V'. Bill Rose Collection

Below: The GAL56 'Medium U' glider (TS510)piloted by Fit Lt Robert Kronfeld, after releasefrom a Halifax tow aircraft. Bill Rose Collection

with it, describing it as very difficult to controland noting that he 'could not relax for a second, beginning right away with takeoff.

The second aircraft known as GAL56/04(TS51O) was designated 'Medium U'. It differed from the first aircraft in having a parallelchord centre section and swept outer leadingedge of 28.4°. The wingspan was 51ft(I5.54m, height 21ft (6.4) and length lOft

245ft 4in (I3.8m)28.4' (leading edge)317ft' (29.45m')350ft' (32.5m')5.819ft (5.79m)8ft 9in (2.66m)RAF 34 Modified11ft 4in (3.45m)43~in (1.1 m)0.5'

4,4001b (I,996kg)58mph. E.A.S. (93.3kph)150mph. E.A.S. (24Ikph)

2Pilot and space for prone observer51ft Ilin (15.8m)36.4' (leading edge)24ft 8in (7.5m)5, 1741b (2,348kg)

Crew

WingspanWing sweepLengthFlying weight

GAL61

CrewWingspanWing sweepWing area (net)Wing area (gross)Aspect ratioLengthHeightAerofoil sectionChord-rootChord-tipDihedral·normalFlying weight(crew +max ballast)

Stalling speedMax towing speed

GAL56 'Medium V'

the wingtips and it was decided to add antispin parachutes in wingtip containers foremergency use.

No overall name was assigned to the glider,but the models were referred to by their wingconfiguration. The first to be completed during autumn 1944 was the GAL56/01 (TS507)'Medium V' which identified its 28.4° leadingedge sweep. An RAF-34 aerofoil section wasused and it had a modified contour toenhance the elevon performance. Thewingspan was 45ft 4in (I3.8m), length was19ft (5.79m) and it was 8ft 9in (2.66m) high.The aircraft undertook taxiing trials at Aldermaston during November 1944 and made itsfirst flight on 17 January 1945 at RAF DunholmLodge in Lincolnshire. This location had beenassigned to GAL as a facility to store Hamilcarheavy gliders and it was chosen for testingbecause the GAL56 was a secret project andthere was less chance of the trials beingobserved by anyone.

For the flight at Dunholm Lodge, an Armstrong Whitley V bomber was used to tow theglider into the air and test pilot Robert Kronfeld was at the GAL56's controls. He reportedthat the aircraft handled fairly well except inextreme conditions and after making 48flights at Dunholme Lodge, TS507 was transferred to RAE Farnborough in June 1945. However, when RAE test pilot Capt Eric Brownflew the GAL56, he was far from impressed

GAL Gliders

Soon after it became established at the end of1942, the Tailless Aircraft Advisory Committee(TAAC) invited a number of aircraft contractorsto submit plans for experimental tailless aircraft that could be used for research purposes.Many companies (including de Havilland,Saunders Roe, Hawker and Fairey) declined totake part, leaving Armstrong Whitworth andGeneral Aircraft Ltd (GAL) as the principal participants, followed by Handley Page which hadalready built the Manx. Designers at GAL hadbeen interested in developing tailless aircraftsince the mid-1930s and proposals were submitted to the TAAC, which swiftly approvedseveral swept-wing prototypes that would beused to test low-speed handling characteristics. Initially, it was planned to build six prototypes, but this was reduced to four. Twowould be gliders designated GAL.56 and twopowered versions referred to as GAL57, usinga single Lycoming R-680-13 radial engine in apusher configuration.

Construction would have to be cost effective, utilising common parts wherever possible. This was necessary to avoid diverting toomany resources away from war production.It was decided from an early stage to use astandard centre section with commonattachment points for wing anchorage. However, it became apparent that there would beproblems interchanging wings with differentprofiles on a standard body and a decisionwas taken to abandon the powered versionsand build four different gliders, taking thesimplest route to keep the project on course.It was also agreed that GAL test pilots andobservers would conduct most of the initialtest flight. Refinement and construction werethen passed to an engineering team at theHanworth factory, Feltham, Middlesex,which was headed by a Czech engineercalled Otto Wels (no connection to the prewar German politician), who specialised inflight control systems.

Each central section utilised a tubular steelframework covered in plywood and thewings were mainly of wooden construction,supported by a single spar. Off-the-shelf landing gear was used for the GAL56, with themain wheels being Dowty units designed forthe Lysander and the tail wheel normallyused on a Bisley. The serial numbers TS507,TS510, TS513 and TS515 were issued on 21October 1944, although it was finally decidednot to proceed with construction of TS515.Each GAL56 accommodated a pilot andobserver in the centre section, with the maindifference between each model being thewing profile. Fins with rudders were fitted to

239ft lOin (I2.lm)245ft' (22.76m')18ft 3in (5.5m)3,0001b (I,360kg)4,0001b (I ,814kg)Two de Havilland Gipsy Major IIfour-cylinder in-line piston engineseach rated at l40hp (I04kW)146mph (234kph)I0-12,000ft (3,000-3,650m)

Below: The HP.75 Manx in flight. Bill Rose Collection

Above: Receiving the semi-official name of Manx(after the tailless cat), the experimental HP.75 wasmainly built from wood and powered by two rearmounted de Havilland Gipsy Major II four-cylinderpiston engines. Bill Rose Collection

Maximum speedCeiling

HP.75 Manx

CrewWingspanWing areaLengthEmpty weightGross weightPowerplant

He made at least two flights in the Manxand reported that the aircraft handled well incomparison to other tailless designs he hadflown. By late 1945, the Manx had logged upto 30 test flights lasting for a total of around 17hours. Talbot and Wright had flown many ofthe missions, but both were killed on 3December 1945 when a prototype Hermes Iairliner they were flying crashed shortly afterleaving Radlett Aerodrome. This loss had adirect impact on the Manx programme andthe aircraft made one more test flight in April1946 and was then placed in storage.

The Manx was an interesting design, whichwas briefly considered for development as atwin-engine transport aircraft, or possibly alight bomber, with a canard configuration.Nothing came of this and the Manx remainedin storage until 1952 when it was broken upfor scrap.


6120ft (36.6m), later reduced to112ft 6in (34.3m)2,000.04fl' (1858m')45ft (13.7m)49,7651b (22,573kg)

470mph (756kph)480mph (772kph)3,000fVper min (9 I4m/per min)Unknown1,500 miles (2,414km)4xMetropolitan·Vickers(Metrovick) F.2/4 Beryl axial·flowturbojet engines, initiallyproducing 3,500 Ib (155kN)static thrustProvisionally, 2x20mm forwardfiring cannons and one rear firingremote controlled turret with2x20mm cannons.12,000 Ib (5,443kg)

CrewWingspan

Armstrong Whitworth AW.50

Armament

Wing areaLengthGross weightMaximum speedat sea levelat 30,000ft (9, 144m)

Rate of climbCeilingRangePowerplant

Bomb load

cated from Plymax (a thin sheet of duraluminbonded to a thicker sheet of plywood). Thisallowed a very smooth finish that met therequirements for effective laminar flow. Thecentral cockpit area accommodated a pilot

early design phase, but engine problemsappear to have ruled this out.

However, it was decided that a one-thirdscale size glider should be built to test theaerodynamics, as there was little data to drawon regarding the behaviour of flying wing aircraft at low speeds or in unusual attitudes. Initially assigned the company reference AW.51,design work started in May 1943, with the project altering to AW.52, which finally becameAW.52G, with the last letter referring to its status as a glider.

Assembly started at the beginning of March1944, although proceedings were relativelyslow as priority was being given to morepressing war production work. Wind tunneltesting continued and AW.52G was finallycompleted in early 1945. It was then assignedthe official registration RG324, but by thistime, the original flying wing bomber hadbeen cancelled. Nevertheless, AW.52G wasseen as a useful research tool and on 2 March1945 was towed into the air behind a Whitleybomber. This first flight was undertaken bythe company's test pilot Charles K. TurnerHughes, who reported no unexpected handling difficulties.

Spruce and plywood (used for the singlebox spar and ribs) were utilised in much ofthe construction, with the outer skin fabri-

Right: One of John Lloyd's early design for anexperimental twin-jet aircraft, which appearedin a UK Patent (2,474,685) filed during 1944and released in 1949. This would eventually leadto the AW.52. Bill Rose Collection/UK Patent Office

Bottom: AW.52G is towed into the air during a testflight. Bill Rose Collection

work, which was supported by the Ministry ofAircraft Production (MAP). Lloyd envisagedthe use of a smooth surface for the aircraft'sskin, fabricated from a fairly thick alloy,strengthened by rolled corrugations of lightergauge metal to maintain adequate rigidity. Atthe centre of the aircraft was a cockpit affording good visibility, with a slightly raised crewsection and a tail-mounted, rear-facing,remotely controlled turret containing two20mm cannons. In addition, it was also proposed to equip the aircraft with two forwardfacing 20mm cannons located in the wingsbetween each engine.

Propulsion would be provided by fouradvanced Metropolitan-Vickers (Metrovick)F.2/4 Beryl axial flow turbojet engines. Thisdesign was producing 3,500 Ib (15.5kN) of staticthrust by 1944, but the F.2/4 remained too unreliable for use in any production aircraft. Lloydhoped that the ongoing problems with the F.2/4would be largely resolved by the time theAW.50 was ready for production and improvedthrust might be available. The engines wouldbe located within the wings on each side of thecockpit drawing air from four separate intakesalong the leading edge of the wing.

Split-flaps would be used, plus wingtip finsequipped with rudders. The AW.50 was to beequipped with a fully retractable tricycleundercarriage. Lloyd's initial plans were foran aircraft with a wingspan of 120ft (36.6m), awing area of 2,000ft' (185.8m') and an overalllength of 45ft (13/7m). The estimated maximum speed was 470mph (756kph) at sealevel and 480mph (772kph) at 30,000ft(9, 144m), with a rate of climb slightly betterthan 3,000fVper min (914m/per min). Theanticipated service ceiling is unknown, butrange was expected to be 1,500 miles(2,424km). Gross weight was 49,7651b(22,573kg) with the bomb load accounting for12,0001b (5,443kg) of this figure. However,within months, the design underwent a significant revision, with the wingspan beingreduced to 112ft 6in (34.3m) and the wingbecoming thinner. As a consequence, thecentre section became recogni able as afuselage and the rear gun turret wasremoved, leading to nominal changes inweight and performance. A smaller twinengine experimental version of this aircraftwas considered at some point during the

An initial Armstrong Whitworth design study foran advanced RAF flying wing jet bomber with thecompany reference AW.50. Bill Rose Collection

In 1942, the Directorate of Scientific Researchapproached Armstrong Whitworth Aircraft(AWA) to develop an aerofoil section for windtunnel laminar flow experiments. As a resultof this, the company's chief designer John'Jimmy' Lloyd (1888-1978) began work onproposals for a military flying wing aircraft.Lloyd produced an initial design study of anadvanced flying wing jet bomber for the RAF,which carried the company reference AW.50and he was authorised to continue with this

Armstrong Whitworth Flying Wings

The final and most advanced glider in the GALexperimental series was the GAL61 (TS515). It wascompleted in 1948 and shown at the SBAC Air Showat Radlell during the same year. It was thenprepared for testing at Lasham, but never flew.Bill Rose Collection

the glider entered a steep dive and becameinverted. Kronfeld told McGowan that he hadlost control of the glider and his observerimmediately bailed out. The altitude wasapproximately 1,000ft (300m) and his parachute opened at about 100ft (30m) making ita close call. Regrettably, Kronfeld stayed inthe aircraft until it hit the ground.

A significantly more advanced GAL experimental glider was nearing completion at thistime, called the GAL61. It had been reassigned the original designation TS515 thatwas intended for use with a fourth GAL56 prototype. GAL61 featured a raised cockpit in thecentre of the aircraft, with a prone position foran obselver within the wing. This design hadthe same 36.40 leading edge sweep as theGAL56 Maximum V and in overall appearance, it loosely resembled the powered

orthrop N-IM flying wing. GAL61 had awingspan of 51ft 11in (15.8m), an overalllength of 24ft 8in (7.5m) and a gross weight ofapproximately 5,1741b (2,346kg). A fullyretractable undercarriage was fitted as standard equipment and the GAL.61 was a trueflying wing in all respects. There were no vertical stabilisers and the aircraft used elevonsand wingtip drag rudders for control. GAL61was completed by mid-1948 and displayedstatically at the 1948 SBAC Air Show atRadlett. It was then returned to Lasham fortesting, but approval to begin test flights wasnever granted and the project was finally cancelled in mid-1949. Although it was the mostinteresting of the four gliders, GAL61 neverflew and is thought to have been broken upfor scrap in 1950.

(13.8m), with a length 23ft 6in (7.16m) and aheight of 9ft (2.74m).

All three gliders were exhibited at the September 1947 SBAC show held at Radlett Aerodrome and the second GAL56 'Medium U'was demonstrated by Robert Kronfeld after aHalifax towed it into the air. But the programme was dealt a severe blow on 12 February 1948 when Kronfeld was killed whiletesting GAL56/0 I (TS507). He had left Lashman Airfield with his observer BarryMcGowan and they were towed behind aHalifax until reaching 16,000ft (4,876m)where separation took place. The purpose ofthe flight was to carry out stall tests, but having made a normal recovery from his first stall

"IIII

"

o

""lJ

"IIII

"

~__ I \

'.... ) '--- .../

nI II IU

(3m). Medium U was assigned the referenceTS51 00 and it flew for the first time on 27 February 1946 at Aldermaston and was thenmoved to Lasham. It was damaged in an accident during 1949 and subsequently scrapped.The third GAL56/03 (TS513) was called 'Maximum V' and featured a 36.40 sweep. It flewfor the first time on 30 May 1947 at Lasham.This version of the glider featured nose flapsand was designed to allow adjustment of thewing dihedral on the ground. It was equippedwith two sets of split flaps. The first hinged atthe 50 per cent chord line, with the secondrear set hinged at 70 per cent. Used one set ata time, this was selected on the ground. Thewingspan of 'Maximum V' was 45ft 4in

1


The AW.52G on the ground. Bill Rose Collection

Armstrong Whitworth AW.52G

Armstrong Whitworth AW.52 Jet (TG363)

5120ft (36.58m)102ft (31m)

2,61 1ft' (242.56m')2,250ft' (209m')80ft (24.38m)75ft (228m)

32ft (9.75m) unconfirmed113,000 Ib (5 I,256kg)101,1501b (45,88Ikg)5x ROils-Royce AJ65 Avonturbojets, each rated at 6,500 Ib(2 .9k ) static thrust4x AJ65 engines, or po iblyRR RB 77 at 7,500 Ib static thru t640mph 1,030Kph575mph (925kph)50,OOOft (15,240m)Carrying a 10,0001b (4,535kg)bomb load, initially expected tobe 1,724 mile (2,776km)1aximum 20,000 Ib (9,071 kg)

bomb load. Either, one nuclear

weapon, two ground penetratingbombs, 3x6,000 Ib (2,72lkg)bombs, or various smallerfree fall bombs

(revised)

CrewWingspan(revised)

Wing area(revised)

Length(revised)

HeightGross weight(revised)

Powerplant

Armament

Maximum speed(revi ed)

Service ceilingRange

Armstrong Whitworth AW.56 Flying WingMedium Bomber Project (OR.229)

the AW.52 prototypes was often difficult andtake-off and landing distances were unsati factory. In May 1954, the second AW.52 wasbroken up for crap and it is thought that theglider met the same fate.

AW.56In late 1946, the UK Air Staff requested proposals for an advanced medium range jetbomber. Known as Operational Requirement(OR) 229, thi et out the RAF's future needsfor a fast, high-altitude aircraft, capable ofdelivering a 10,000 Ib (4,535kg) bomb to arelease point 1,500nm (I726 mile or2,776km) distant. Although the primalyobjective was the carriage and delivery of asingle atomic bomb, no British nuclearweapon had been produced at this time anda second requirement designated OR. I 00 1(later given the codenarne 'Blue Danube')was issued by the Air Staff to develop a plutonium bomb. Both the aircraft and the bombrepresented a significant technical challenge.The RAF was seeking a bomber that wascapable of sustaining a speed of 500kts(926kph) at an altitude of 50,000ft (15,240m)with a gross weight of 100,0001b (45,359kg).Bearing in mind the state of aerodynamicknowledge and ga turbine technology at thetime, this was a very tall order.

exhaust from the engines and there was aboundary layer control system connected tothe engine air intakes and pressure balancedcontrol surfaces. The aircraft also utilised afully retractable tricycle undercarriage with asteerable nose-wheel.

Like the AW.52G, the AW.52 was equippedwith vertical wingtip fins and rudders andcanisters were attached that contained antispin parachutes for emergency use. The trailing edge of the nying wing was occupied by asubstantial Fowler nap, which was contouredto allow for each j t exhaust pipe. After aperiod of tests and minor modifications, theaircraft was partly dismantled and transported by road to the RAF ExperimentalEstablishment at Boscombe Down. Havingbeen reassembled, AW.52 spent the nextcouple of months undertaking ground testsand taxiing trials until a br ak in the weatherallowed the first night to be made on 13

ovember 1947.The trial was undertaken by Armstrong

Whitworth test pilot Eric Franklin whoreported that the aircraft handled as anticipated. Following this ucce the AW.52 wasreturned to Bitteswell Airfield (no longer inexistence) for further testing. The secondAW.52 (TS368) was completed in the Whitleyworkshops during the summer of 1948 anddiffered slightly by having two less powerfulRolls-Royce Derwent 5 engines, each producing 3,5001b (15,56k ) of static thrust.Rolls-Royce engines appear to have beenchosen for reasons of reliability, although itremains unclear why Derwent turbojets werefitted to the second aircraft in preference tothe similar Nene units. TS368 fir t new on ISeptember 1948 and night-testing with bothaircraft continued until 30 May 1949.

On this date, John Lancaster was undertaking a series of trials in the vicinity of theBitteswell Aerodrome with TS363. After entering a dive at about 320mph (510kph), Lancaster encountered severe pitch oscillationand realising that the aircraft was about tobreak up, he ejected, becoming the firstBriti h pilot to use this system in an emergency. The second AW.52 was transferred tothe RAE Farnborough in October 1950 wheretesting continued until September 1953 whenArmstrong Whitworth left the programme.As a consequence, the RAE decided to conclude operations.

Exactly how useful the Armstrong Whitworth nying wing programme proved to beremains debatable. Lloyd hoped that thiswork would lead to a large nying wing airlinerpowered by six turbojets, but there were toomany technical obstacl s. Laminar nowproved to be largely unworkable, control of

AW.52G would normally glide at around 100120mph (I60-190kph), with a maximum permitted speed of 250mph (400kph) and talloccurring at about 60-65mph (96-1 04kph).

Because there was so much interest inboundary layer control, an experimental system was devised to draw in air through a slotforward of the elevons. The idea was toreduce the possibility of wingtip stall at lowerspeeds and to achieve the suction, smallwind-powered pumps were fitted to each ofthe main wheel truts. Trials continuedthroughout 1945, with the aircraft usuallybeing nown by company test pilots CharlesTurner-Hughes or Eric George Franklin. Somerefinements were made to the glider as theproject progressed and it was then decided tobuild two somewhat larger experimental jetpowered nying wings. The project wouldreceive the company reference AW.52 andapproval und r the original MAP specificationE.9/44 by the Ministry of Supply.

The new aircraft would be approximatelythree quarters the size of Lloyd's initial designfor the AW.50. Its gross weight would be about34,0001b (15,422kg) and two Rolls-Royce turbojets would provide propulsion. In overallappearance the larger jet-powered AW.52was imilar to the glider, although the centreof the wing now contained a recognisablefuselage section that protruded forward. Thetwo turbojet engines were buried in the wingon each side of the cockpit section and the aircraft's internal structure was somewhat different to the AW.52G, with metal being usedthroughout. The first AW.52 (TS363) was completed in Armstrong Whitworth's assemblyshop at Whitley, Coventry, by early 1947. It hadalready been revealed to the public as a mailcarrying aircraft, although this appears to havebeen largely public relations spin.

Like the glider, this aircraft had an initialsweep of 17.5°, followed by 34° to the wingtip,which provid d the distinctive boomerangshape. The AW.52 had a wingspan of 90ft(27Am), a length of 37ft 4in (I I Am) and aheight of 14ft 4in (4.4m). Empty, the aircraft

weighed 19,6621b (8,919kg), with a grossweight of 34, 1541b (15,492kg) and the aircraftcarried a crew of two. The engines chosen forthe fir t aircraft were Rolls-Royce ene 2 turbojets, each rated at 5,000 Ib (22.2k ) of static thrust. The estimated maximum speed ofthe AW.52 was about 500mph (800kph), witha ceiling of about 35-40,000ft (10-12,000m)and a range of approximately 1,000 miles(1,600km). The aircraft featured a pressurised cockpit and the pilot was equippedwith a Martin Baker Mk I ejector eat,although not the passenger. The AW.52 wafitted with a thermal de-icing system using

253ft lOin (16Alm)443.04ft' (41.16m')19ft 4in (5.89m)8ft 4in (2.54m)6,0001b (2,724kg) approx

one100·120 mpg (I 60· 190kph) approx250mph (400kph)

2Initial 17.5°, followed by 34° tothe wingtip (leading edge)90ft (27Am)1,314ft' (122m')37ft 4in (I lAm)14ft 4in (4.4m)19,6621b (8,919kg)34,1541b (15,492kg)2x Rolls-Royce I ene 2turbojets,each rated at 5,000 Ib (22.2k 1)static thrust500mph (800kph) approx35·40,000ft (10-12,000m) approx1,000 miles (I ,600km) approx

Wing panWing areaLengthHeightEmpty weightGro sweightPowerplant

Maximum peedCeilingRange

CrewSweep

CrewWing panWing areaLengthHeightGross weightPowerplantGlide speedMax permitted speed

and rear eated observer, with onventionalnight controls, aside from a large handbrake

style lever used to actuate additionalhydraulically-operated, horizontal controlsurfaces called 'correctors'. In addition to theother control surfaces, a substantial hydrauli-

ally operated one-piece slott d nap with alength of 15ft 4in (4.67m) is positioned alongthe entire trailing edge of the central wingsection. As a precaution during testing, antispin parachutes were housed in canisters oneach wingtip.

AW.52G utilised a fixed tricycle undercarriage with brakes and a non-steering nosewheel. The wingspan wa 53ft lOin (16Al m),with a wing area of 443.04ft2 (41.16m'). Overall length was 19ft 4in (5.89m), the height was8ft 4in (2.54m). The gross weight of the aircraftwas approximately 6,0001b (2,724kg). The

The first of two AW.52 experimental jet aircraft(TG363) which were based on designs for thelarger AW.50 bomber. Two Rolls-Royce Neneturbojets provided propulsion, each rated at5,000 Ib (22.24kN) static thrust. Bill Rose olleclion

A staged company photograph of the AW.52G withcrew and observers. The unusual attachment to thetrailing edge of the port wing is a frame for the pitotcomb used to measure airflow. Bill Rose Collection


engineers into uncharted territory and it wasrecognised that a small demonstrator wasrequired to establish the viability of variousswept wing configurations.

During October 1945, the company's ChiefDesigner Ronald Bishop finally selected a smallexperimental tailless proposal known asDH.I 08, which was based on a Vampire with asingle swept tail fin. Propulsion was to be provided by a single de Havilland Goblin 2 turbojetand because this prototype drew heavily on aproven design, the development time and costcould be minimised. In early ]946, the Air Ministry approved full development of what wouldbe Britain's first swept wing aircraft. Two similar, but slightly different prototypes would bebuilt to provide data for the proposed jet airliner, plus future jet fighters like the DH.] 10 SeaVixen. One of the experimental aircraft wouldbe used to evaluate the performance of theswept wing at relatively low speeds while theother would have a transonic capability. Theseaircraft were now assigned the official (Experimental) references E. ]/45 and E.II/45.

Much of the DH.I08's design can be credited to John Carver Meadows Frost (19151979) who is now remembered for his workon the Avrocar project in Canada. Both of theDH.I08 aircraft started life as fuselages forVampire F.l jet fighters that were takendirectly from the production line. As originallyplanned, the first aircraft was fitted with aGoblin 2 turbojet engine, producing 3,0001b(l3.4kN) static thrust. A new wing with a 430

sweep and fixed leading edge slats were fit-

2x Bristol Orpheus turbojets,each rated at4,8591b (21.6kN)static thrust.lOx Rolls·Royce RB I08 turbojets,each ratedat2,101lb (9.34kN)static thrustI,483mph (2,387kph)unknownunknown

I17ft 6in (5.36m)83'70ft7in (21.59m)16,3091b (7,398kg)

(VfOL operations)

DH.I08 Swallow

Armstrong Whitworth AW.171

CrewWingspanSweepLengthGross weightPowerplant(horizontal flight)

Maximum speedEnduranceRange

In 1943, the Brabazon Committee wasformed to consider requirements for civil airtransportation once the war had ended. Thisresulted in approaches being made to a number of aircraft contractors for submissionsand one company who responded was deHavilland, which had studied the Committee's Type 1V requirement for a jet-powered] OO-seat airliner. This resulted in proposalsfor a scaled up Vampire fighter, a tailless flying wing using four Ghost turbojets and amore conventional concept that would eventually become the DH.I06 Comet. However,such a project would take the designers and

(l2,192m) and progressively climbing to50,000ft (l5,240m), which would be attainedafter approximately 2 hours and 30 minutes.It was suggested that the Avon engines mightbe replaced by MetroVick F.9s, which wouldoffer improved thrust, lower fuel consumption and the ability to climb directly to 50,000ft(15,240m). However, the requirements for anew bomber were lowered after the TenderDesign Conference took place and this led toa significant revision of the AW.56 proposal,resulting in a slightly smaller aircraft. Theredesigned AW.56 would be fitted with thenew Rolls-Royce RB.77 engines, allowingthe use of four rather than five units. Thismeant that the tail engine was removed, leading to better streamlining and a noticeableweight reduction. This improvement wouldprovide the AW.56 with performance similarto the proposed F.9 powered version.

Another alteration to the revised aircraftwas the use of a raised cockpit canopy for thepilot. Offset to the port side, this would haveimproved visibility considerably. AWA anticipated full completion of this second designwithin two years and testing of the first prototype about five months later. But the designwas finally rejected by the MoS in favour ofthe Avro 698 and Handley Page H.P.80 whichbecame the Vulcan and Victor.

Underside view of OH.I08 TG283 in flight.Bill Rose Collection

AW.l71The AW.171 is often listed as a supersonic flying wing by aviation sources and thereforedeserves to be briefly mentioned. ArmstrongWhitworth produced several designs duringthe mid-1950s to meet a MoS specification fora one-man supersonic research aircraft witha vertical take-off and landing (VTOL) capability. The first was the highly swept AW.17]which would be powered by two BristolOrpheus turbojets for horizontal flight and 10centrally located Rolls-Royce RB.I 08 enginesmounted in an upright position for lift. Thiswas followed by the AW.I72 which utilised aslightly different wing profile and propulsionsystem. It appears that Rolls-Royce's leadingengine designer, Alan Arnold Griffith, wasinvolved with this project and he produced anumber of broadly similar designs which alsoutilised centrally located lift engines.Although the supersonic VTOL demon tratorwas cancelled at an early stage, there wassome lingering interest in the idea of a largerVTOL bomber or transport aircraft based onthe AW.171, which continued until 1957when a wide number of advanced researchprojects were officially cancelled.

effective laminar flow. At this time, experiments to determine the viability of laminarflow had been sponsored by ArmstrongWhitworth and were being conducted atRAE Farnborough with a modified Hurricanefighter (23687). Initial results had been disappointing, but research continued, with amodified Gloster Meteor Mklll jet fighterand AWA's flying wing programme. TheArmstrong Whitworth laminar flow wing forthe AW.56 was to have a span of 120ft(36.58m) and an area of 2,611 ft' (242.56m').The overall length of the aircraft was initially80ft (24.38m) with an unconfirmed height of32ft (9.75m) and a gross weight of 113,000 Ib(51,256kg). To meet the performancerequirement of B.35/46, five Rolls-RoyceAJ65 Avon turbojets would be used forpropulsion, each rated at 6,5001b (28.9kN)static thrust. Four engines would be installedin the wing roots with air intakes on each sideof the cockpit and another engine would belocated in the tail, with its own dorsal air inletlocated mid-way along the fuselage. Thegross weight was calculated at 113,0001b(51 ,256kg), which suggested that the aircraftwould have a maximum speed of 640mph(I ,030kph) and a ceiling in excess of 50,000ft(l5,240m).

The AW.56's fuselage section would bebuilt using fairly conventional materials andconstruction methods, although the two-sparwing would be covered with an unusualmulti-layer skin similar to that developed forthe experimental AW.52 flying wing.

A fully retractable tricycle undercarriagewas planned for the bomber and a flight control system developed for the AW.52 wouldbe used, comprising of two tandem controlsurfaces called a 'corrector' and a 'controller'.The 'corrector' acted as a longitudinal trimcontrol and the 'controller' was similar infunction to an elevon. A crew of five wouldman the aircraft, housed in a pressurisednose section, with access to the bomb bay toallow in-flight arming of the nuclear weapon.No ejector seats would be installed, but it wasproposed that the entire nose section wouldbe jettisoned in an emergency and could belowered to the ground by four substantialparachutes. As an alternative to a nuclearweapon, the AW.56 could carry a variety ofconventional stores with a maximum weightof 20,0001b (9,071 kg). Another interestingdesign feature was the bomb bay doorswhich opened transversely with sections sliding fore and aft. This was considered an effective way of minimising impact on theaircraft's speed and trim.

A long-range mission would involve the aircraft ascending to an altitude of 40,000ft

The revised AW.56 design using fourof the new Rolls-Royce R677 jetengines and undergoing changes tothe cockpit and various aerodynamicfeatures. Bill Rose Collection

The initial design of the AW.56 jetbomber produced to meet Ministry ofSupply Specification 6.35/46 in early1947. Bill Rose Collection

vv

rating a host of advanced features with thecompany reference AW.56.

From the outset, Armstrong Whitworthbelieved that a tailless configuration wouldgenerate fewer aerodynamic problems attransonic speeds. They also proposed a seriesof wing slots that would allow boundary layercontrol at all speeds, leading to theoretically

47~7f1~n:E]~I>'..,j

Arm tr ng Whitworth r sponded toR.229 with an initial ubmission and not sur

prisingly th de igners drew heavily on theirflying wing and laminar flow research. Afterth Ministry of Supply issued the more spe-ilk pecification B.35/46 in early 1947, Arm

strong Whitworth submitted detailed plansfor a swept-wing tailless jet bomber, incorpo-


I39ft (II. 8m)25ft lOin (7.9m)

,800 Ib (3,991 kg)I xde Havilland Goblin II turbojetrated at3, I00 Ib (13.8kN)static thrust280mph (450kph)

/A730 miles (I, I74km)

I39ft (11.89m)327. 6ft· (30.47m·)I33kglm' (27Ib/ft')26ft lOin (8.17m)14ft (4.27m),940 Ib (4,064kg)

I xde Havilland Goblin 4turbojetrated at 3,73 Ib (16.67k ')static thrust0.42677mph (I ,090kph)40,000ft (12, 192m)

CrewWingspanLengthGross weightPowerplant

De Havilland DH.I08 (TG283)

Maximum speedCeilingRange

De Havilland DH.I08 (VW120)

CrewWing panWing areaWing loadingLengthHeightGross weightPowerplant

ThrusVweightMaximum peedCeiling

post-war era meant actually going out and trying an idea to see if it worked. Both the US andRussians lost experimental aircraft during thisperiod, simply as a result of pushing the envelope that little bit further.

As a footnote, the DH.I 08 trials would inspirethe British film director David Lean to make afictional movie called The Sound Ban-ier,which was released in 1952. Starring RalphRichardson and Ann Todd, it wa very successful at the tirne, but is now largely forgotten.The film featured a 'n w' j t fighter called thePrometheus that was used in an attempt tobreak the sound barrier. Prometheus was actually a ene-powered Supermarine Swift Type535 prototype (WI 19).

descent at 30,000ft (9,000m). Although therewas no serious instability, Derry later reportedthat the controls became heavy and unresponsive, despite the power boost system. But oncehe dropped down below Mach 0.96, everythingreturned to norrnal and Derry resurned hisnight to the de Havilland fa ility at Hatfield.

Trials with the third DH.l08 continued intothe following year, when the aircraft appearedat the Farnborough Air Show and took thirdplace in the SBAC's Challenge Trophy AirRace. It was then officially passed to the Ministry of Supply which continued with testing atRAE Farnborough. Unfortunately, the thirdDH.I08 was lost on 15 February 1950 with itspilot Squadron Leader Stuart Muller-Rowlandbeing killed. He had been undertaking dives athigh transonic speeds above Buckingharnshire when the aircraft broke up. Wreckage carne down in the Little Brickhill area,with a number of parts found near Bow Brickhill Church and some components as farremoved as Husborne Crawley. The local fireservice was mobilised, along with the police,who were instructed to cordon off the area asome aspects of the aircraft remained classi

fied. Witnesses reported hearing an explosion,although this may have been a onic boom.The cause of the accident wa later determined to have been an oxygen system failure,resulting in the pilot losing consciousness.

The first DH.l 08 was still Oying, but on I May1950, it crashed at Hartley Wintney, Hants,during stalling trials killing the pilot SquadronLeader George Genders. The three DH.108Swallow aircraft completed a total of 480nights, which provided invaluable data,despite all being lost in fatal accidents. Manyobservers have claimed the aircraft werejinxed, cursed or the design was fatallyOawed, but other believe these are notentirely fair comment . At that time, theDH.I 08 represented the cutting edge of aeronautical research and these aircraft were regularly Oown at their performance limits. Muchof the research undertaken in the irnmediate

De Havilland's third DH.108, based on aproduction Vampire F.5 fighter and configured forhigh-speed flight, was given the official referenceVW120. Piloted by John Derry, it set a world airspeed record of 605.23mph (974kph) on a 62-mile(IOOkm) closed circuit during April 1948.Bill Rose ollection

As a consequence, the main spar fractured,the wings sheared off and the fuselage cameapart. Wr ckage showered down into themuddy waters of Egypt Bay near Gravesend,Kent, and de Havilland was killed. Recoveryof debris proved especially difficult and Geoffrey de Havilland's body could not be located,although it finally washed ashore at Whitstable on 7a tober 1946. This tragic accidentwould hold up high-speed night testing foranother year, during which time it wasdecided that the problems that had cau edthe accident could be effectively dealt with.In July 1947, a decision was taken to replacethe second DH.108 with a similar air raft,albeit with a number of modifications andimprovements.

The third DH.I 08 was based on a production Vampire F.5 fighter and it received theofficial serial number VW120. It was slightlymore streamlined than TG306 with a pointednose, giving it an overall length of 26ft 9~in

(8.165m). A sleeker, more aerodynamiccockpit canopy was fitted, the pilot's ejectorseat was lowered, which reduced visibilityand the cockpit remained unpressurised.With engine performance steadily (althoughslowly) improving, this aircraft was fitted withthe latest Goblin 4 turbojet, producing 3,750 Ib(I6.68kN) of static thrust. As a final majorupgrade, the third Swallow was fitted withpower-assisted elevons to address the problem of pitch oscillations.

Replacing Geoffrey de Havilland as thecompany's hief test pilot was wartime nightfighter ace John Cunningham (1917-2002)who made his first night in the new Swallowon 24 July 1947. The following year on 12 April1948, this aircraft piloted by de Havilland testpilot John Derry (I 921-1952), set a new worldair speed record of 605.23mph (974kph) on a62 mile (I OOkm) closed circuit, later earninghim the prestigious Segrave Memorial Trophy_ Flying this aircraft, Derry would alsobecome the first British pilot to exceed thespeed of sound, which took place on themorning of 6 September 1948 above Windsor.

For some weeks the Swallow had beentested at gradually increasing speed and onthis occasion Derry decided that conditionswere good enough to push the aircraft a littlefurther. Rapidly descending from about40,000ft (I2,000m), the aircraft nudged pastMach I just before Derry pulled out of th

bridge was being used for classified RAFexperimental work and its lengthy, wellmaintained runway made this an especiallysuitable location. Somewhat surprisingly, thebase was closed in March 1948 and passed tothe USAF everal years later.

The ecrecy surrounding the DH.I 08 continued until the beginning of June 1946 whenParliamentary Secretary of the Ministry ofSupply Arthur Woodburn visited de Havillandat Hatfi Id and disclosed the aircraft's existence (which had now returned to the facility). While minor modifications were beingmade to the aircraft, it was already apparentthat a tailless design based on prevailing technology was less than ideal for an airliner.Meanwhile, work continued on constructionof the second prototype designed for highspeed night, which was fitted with a slightlymore powerful Goblin 3 engine rated at3,3501b (I4.9k ) static thrust. The aircraftwas marginally shorter than the first DH.I 08with an overall length of 25ft lOin (7.874m) asopposed to 24ft 6in (7.467m) and featured a45° leading edge wing sweep. Automaticleading edge slots were fitted that could belocked by the pilot, a more streamlined cockpit canopy was used and there were improvements to the night controls.

This aircraft received the serial numberTG306 and was built to explore night at muchhigher speeds and perhaps supersede theexisting air speed record of 616mph (991 kph).

TG306 first flew during June 1946 andapp ared at the Society of British AircraftConstructors (SBAC) September 1946 showat Radl tt (which moved to Farnborough in1948). As well as being a static exhibit, it wasOown by Geoffrey de Havilland during theshow's final event and clearly impressed thevisitors. A couple of weeks later, on 27 September 1946, Geoffrey de Havilland took offfrom Hatfield in the second DH.I08. He hadnow logged 13 hours in the aircraft andintended to push it towards its limits duringpreparations for an attempt on the air peedrecord, which had now been unofficially broken in this aircraft. The emergency anti-spinparachute containers had been removed andthe aircraft's metallic surface had been polished to a bright finish. However, things wentdisastrously wrong above the Thames Estuarywhen de Havilland encountered pitch oscillations at Mach 0.9.

The clean, compact de Havilland DH.l 08 taillessexperimental aircraft, which was based on theVampire jet fighter and drew heavily on wartimeGerman aeronautical research. This photographshows the second prototype, TG306.Bill Rose Collection

" 10

r- ed IMH 3

The third and most advanced DH.t08,equipped with a Goblin 4 turbojet,producing 3,750 lb (I6.68kN) of static thrustand power-assisted elevons to assist withcontrolling pitch oscillation problems.Chris Gibson

enced this design. Having been completed inwhat would now be regarded as an astonishingly short period of time, the aircraft wasassigned the official serial number TG283 andthe DH.I 08 made its first night on IS May 1946,with test pilot Geoffrey Roald de Havilland JraBE (I 91 0-1946) at the control . (Son of theoriginal Geoffrey de Havilland.) The test nightwas relatively uneventful and de Havillandreported the DH.I08 handled well, despitebeing restricted to a maximum speed of280mph (450kph).

While the DH.I 08 was not a classified project, some of the aircraft's technology wasconsidered sensitive and details of night trialswere treated with secrecy. There were runway repair problems at Hatfield, so it was aneasy decision to continue with trials at RAFWoodbridge in Suffolk. At that time, Wood-

t d. Utilising quite a lot of wood in its construction, the new wing had a span of 39ft(I1.88m) and an area of 328ft' (30.4m'),which was 15% greater than the Vampire.

ontrol of roll and pitch was undertaken byelevons located outboard of the trailing edgesplit Oaps and containers were fitted to thewingtips that carried small anti-spin para-

hutes for emergency use.A single vertical fin now replaced the twin

tail boom fitted to the Vampire and thisresulted in a sleeker more elegant looking aircraft which was given the name wallow,although it was never formally adopted. As ar suit, this elegant-looking aircraft appearedto be something of a Vampire crossed with awartime Messerschmitt Me 163B rocket interceptor, perhaps reOecting the fact thatGerman aeronautical development had inOu-


General arrangement of the Rolls-RoycevrOL flying wing designed in the late1950s by Geoffrey Wilde and John Coplin.Bill Rose CollectionJUK Patent Office

They settled on a basic layout that wouldutilise a large number of vertically positionedturbojets in the centre of the aircraft to provide lift. An illustration shows the use of 30 jetengines, but the complexity of such a systemwould probably have made this design unattractive for a production aircraft. Louvredinlet and exhaust shutters would be used tocover the engine in level flight and four jetengines in ducts mounted on the trailing edgeof the aircraft would be used in forward flight.Wilde also envisaged a boundary layer, dragreduction system with air being drawnthrough conduits from the wing and fed to theintakes of the rear-mounted engines.

Proposed dimensions of this VTOL designare unknown, although the cluster of enginesat the centre of gravity would result in a substantial wing thickness/chord ratio of asmuch as 20 per cent. Combined with a relatively low structural weight, this would allowa considerable payload capacity for cargo orpassengers within the forward wing on eitherside of the central cockpit area. As a light military transport, it might have been especiallyuseful for inserting and extracting SpecialForces during unusual operations.

General performance figures are unknown,but it seerns likely that speed, range and payload capacity would have been superior to thepresent day Bell-Boeing V-22 Osprey. Nothingcame of this paperwork study, although RollsRoyce applied for a patent in 1959, namingWilde and Coplin as the inventors. This waspublished in 1963 and it received the reference GB920875. There was no further notableinterest in flying wings at Rolls-Royce.

1-8 -3f

258Ft (l7.6m)750Ft' (69.67m2

)

55ft (167m)2xRolls·Royce AJ65 Avonturbojets, each provided 6,5001b(28.9k ) stalic thrust. Specificafterburner performanceunknown.650·700mph (I ,OOO,!, 100kph)e timate50,OOOFt + (l5,240m +) estimate4x30mm Aden cannons

Rolls-Royce vrOL Flying Wing

25

In 1956, Geoffrey Light Wilde was appointedas the Head of the Advanced Projects DesignOffice at Rolls-Royce in Derby. An outstanding engineer, Wilde is now best rememberedfor his initial work on the RB211 engine, butback in 1956, his newly formed departmentbegan detailed studies of many differentideas for civil and military engine applications, including a number of VTOL aircraftdesigns. Wilde was particularly interested indeveloping a fixed wing VTOL aircraft andspecifically, a flying wing, which would use acluster of small engines for lift with separatepropulsion for horizontal flight. He began todevelop this particular idea in associationwith one of his designers called John Coplinand it seems very likely that A.A. Griffith, whowas the company's leading VTOL proponent,also took part in this study.

CeilingArmament

Hawker P.I077

CrewWing panWing areaLengthPowerplant

Maximum speed

I55Ft (l6.8m)745ft' (69.2m')43Ft 6in (l3.3m)27,260 Ib (l2,365kg)2xRolls-Royce AJ65 Avonturbojets, each providing 6,500 Ib(28.9k ) static thru t632mph (1,0 17kph) at sea level50,000ft+ (15,240m+) estimate3x30mm Aden cannons

Hawker Siddeley PJD.l44

One of the more unusual fighter designs toemerge from Hawker Siddeley's design officeat Kingston during 1949 was the tailless twoman P.I077 jet fighter, possibly intended tomeet Specification FA/48. It is almost as if thedesigners had taken a look at the WestlandPJD.144 proposal and then set about upgrading it. The wingspan was 58ft (17.67m), thelength was 55ft (16. 76m) and was to be powered by two stacked Rolls-Royce Avon turbojets equipped with afterburners. Air intakesfor the engines would be positioned aroundthe fuselage about mid-wing and the P.I 077would carry 1,000 Imp gallons (4,546 litres) offuel. Specific perforrnance figures areunknown, but this design was probablyintended to be capable of high tran onicpeed at altitude with a ceiling in the region of

50,000ft (I5,240m). The aircraft carried acrew of two and would be equipped with airintercept radar. The undercarriage consistedof a bicycle configuration with fullyretractable twin nose wheels and four largermain wheels. It seems almost certain thatoutrigger stabilising wheels would have beennecessary. A radar dish would be fitted withinthe nose of the aircraft and two large verticalfins and rudders were positioned in the centre of each wing. Proposed armament werefour 30mm cannons in a ventral pack. eedless to say, this interesting design never progressed beyond the drawing board.

considered their options for an aircraft with atail and fitting one would negate any dragreduction advantages of the tailless design.The selection process continued during thefollowing year with the de Havilland DH.II 0finally being chosen as the best availablede ign. This led to a contract being issued inOctober 1948 for the construction of a DH.II 0prototype to meet Specification NAO/46 andfor evaluation as a new RAF night fighterunder Specification FA/48.

Maximum speedCeilingArmament

CrewWingspanWing areaLengthGross weightPowerplant

Westland PJD.l44

British Tailless Aircraft

a split central duct feeding both engines. ThePJD.129/144 concept has been comparedwith the Junkers EF.128 which was a Germanproposal produced for the 1945 EmergencyFighter Competition. To what extent thedesigners at Westland were influenced bycaptured research material is hard to say asmuch of the documentation for the EF.128project fell into Soviet hands. But it appearsthat the Westland fuselage had more in common with aircraft like the de Havilland Vampire and the similarities to the German designare rather superficial.

The main differences between the PJD.129and the PJD.144 were alterations to the wingsand fins. The leading edge wing sweep wasreduced from 45° to 38°, made possible bychanges to the wing's outer chord and the finsize was slightly increased. PJD.142 wasbroadly similar to this aircraft, but lacked thevertical wingtip fins and utilised a singleupright tailfin. PJD.143 was the most conventional of these studies with an upright fin andhorizontal tail surfaces. It was also decided toalter the engine layout and have the turbojetsside-by-side. Initially, Westland designedthese concepts around two unspecified turbojet engines in the Rolls-Royce ene classwith a static thrust of about 5,000 Ib (22.24kN),although the RAE decided that the newly prototyped and more advanced Rolls-Royceaxial-flow Avon (then known as the Axial Jet- AJ.65) was the preferred choice. Estimatedmaximum speed at altitude was about630mph (I ,0 13kph) and general dimensionsand weights complied with the AO/46 specification. Armament appears to have been thesame type for all variants and in this ca e,three 30mm cannons were proposed.

A fully retractable tricycle undercarriagewas proposed for all models and the aircraftwould have been equipped with arrestorlanding gear. A radar dish for airborne interception was housed in the aircraft's nose andthis system would have been operated by asecond crew member who was seateddirectly behind the pilot and facing rearward.On 15 December 1947, a Design Study Conference was chaired by the Director-Generalof Technical Development (Air) for the MoS,Stewart Scott-Hall, to assess all the submissions for NAO/46. The Westland proposalswere an early casualty and it was decidedthat performance projections for this aircraftwere unsatisfactory and there were generalconcerns about the tailless design. Delegatesfelt that in addition to lacking adequate performance, the Westland proposal might suffer from tip tailing and the anticipatedapproach speed was too high. The Conference also decided that Westland had not fully

Secret Projects: Flying Wings and Tailless Aircraft

Hawker-Siddetey's PlO77taillesstwo-man jet design produced bythe Kingston Design Office in1949. Bill Rose ollection

24

The tailless Westland PJDI44 carrierbased warplane designed in responseto Specification N.40/46 during the late1940s. Bill Rose Collection

issued to a number of aircraft contractors andone of the companies that responded wasWestland. It undertook a detailed study,which resulted in an initial proposal designated PJD.129, followed by three differingvariations. These were PJD.142, PJD.143 andPJD.144, with the designs completed in late1947.

The version preferred by Westland was thePJD.144, which was similar in overall appearance to the initial PJD.129 proposal. It was acompletely tailless design with verticalwingtip fins and rudders and this proposalutilised two turbojets in a stacked configuration along similar lines to the later EnglishElectric Lightning. Air intakes for the engineswere positioned on each side of cockpit with

In the immediate post-war years, the RoyalNavy b gan to consider its future needs for amore advanced carrier-borne twin jet fight rwith the ability to operate at night. It wouldneed to be capable of achieving a maximumspeed of 500kts (927kph), have a gross weightof no rnore than 30,000 Ib (13,608kg). A maximurn wingspan of 55ft (16.8m) was recommended and folded, the span could be nogreater than 18ft (5.5m). The rnaximum permissible length was 43ft (I 3.1 m). As istedtake-off was anticipated and the armamentwould cornprise two or ideally four 30mmcannons. This Operational Requirement(0R.246) led to Specification NAO/46 being

Westland PJD.144

Sir Bames Wallis Kt, CBE, FRS, RDI, FRAeS(1887-1979) is best remembered as the scientist who devised the bouncing bomb thatwa used by the RAF in May 1943 to attack theM6hne, Sorpe and Eder dams in the Ruhr.This mission was called Operation 'Chastise'(more widely known as the DambustersRaid) and it eventually earned Barnes Wallisinternational fame, making him one of therelatively few British aircraft designer to beportrayed in a feature film (The Dambuslers,1954). The bouncing bomb project wasessentially a one-off undertaking and when it

Vickers Swallow

The single-seat Heston JC-9 which wasbuilt in sections and transported toWeybridge for use during the Swallowprogramme. However, it was neverreassembled and remained in a hangaruntil the project ended and it was finallyscrapped. Bill Rose Collection

At this time, the design that would be used forthe fir t two full-sized prototypes (VX770 andVX777) was essentially complete, althoughthe RAE had insisted on some significantchanges to the wing structure in late 1948,which would delay the start of construction atChadderton and Woodford until early 1951.Roly Falk undertook the maiden flight of thefir t Type 698 prototype (VX770) on 30 August1952. The test went well, aside from problems with trailing undercarriage doors whichrequired careful inspection by a Vampirechase plane and a company 707. It was finallydetermined that this didn't interfere with theaircraft's ability to land and Falk put VX770down on the runway with no problems.

Production aircraft were to be power d withBristol Olympus engines, but these were notavailable at that time, so VX770 was fitted withfour lower-powered Rolls-Royce RA.3 Avons.In October 1952, it was decided that the newbomber should be given a proper name and aCommonwealth capital city was favoured.Ottawa was the preferred choice, but this ideawas soon dropped and Vulcan wa elected.

resulted in the aircraft crashing into the groundmoments after it left the runway. Both testpilot and Chadwick were killed. This represented a significant setback to the programmeand almost led to cancellation of the contract.Within a matter of weeks, (Sir) William Farrenhad been appoint d as the new TechnicalDirector and soon managed to calm officialworries. This ensured continuation of the project, with Ministry confirmation being receivedon 27 November 1947.

Longitudinal stability remained a problemand the idea of utilising a horizontal tailfinsimilar to the Gloster Javelin was briefly considered. This was eventually dropped, but asingle upright tailfin was retained. There werealso issues with the staggered engine layoutand this was finally dropped in favour of a lesscomplicated side-by-side arrangement. Workon the jet bomber continued and Avro wasawarded a contract to proceed to the hardware stage on 1 January 1948. The companywould now build a full-sized mock-up of thebomber, two scale-sized proof-of-conceptdemonstrators and two full sized prototypes.

The demonstrator initially comprised ahalf-sized aircraft called the Avro 710, whichwould be powered by two Rolls-Royce Avonturbojets, and a one-third sized single RollsRoyce Delwent-engine version with the reference Avro 707. Work began on the prototypesin 1948, but it was realised that building theAvro 710 would be as complex and expensivea a full sized aircraft, so construction of thisaircraft was stopped. However, it was decidedthat the number of Avro 707s should beincreased and five would eventually be built.

The first Avro 707 (VX784) flew on 4 September 1949, but crashed on 30 September1949, killing the pilot Fit Lt Eric Esler afterentering a low-speed stall which is b lievedto have been caused by faulty air brakes.

proposed an additional crew area within theleading edge of the port wing. There wouldbe two separate bomb bays at each side ofthe engine compartment, each havingenough space to contain a single large bomb.The fully retractabl undercarriage layout is alitlle less clear from the one availabl drawingof this early design, but it appears to comprisetwo rear-mounted main wheels and two separate nose wheels. The whole package wassomething of a design tour-de-force, combining many new ideas in a largely unprovenaerodynamic shape.

When Roy Chadwick finally retumed to theoffice he was not entirely pleased with thedirection the project had taken and it seemsthere were disagreements about what he perceived to have become a science fiction concept. However, Roy Chadwick finally camearound to the idea of flying wing design andsoon began to suggest modifications andimprovements. The appearance of the newType 698 began to evolve towards a triangular delta-winged shape, although some of theexisting features were retained. The forwardengine inlet was replaced with two intakes atthe leading edge and the rather strange dualcockpit layout was replaced with a singleenclosure. Chadwick kept the two bombbays, but now decided that wingtip stabiliserswere necessary. The undercarriage underwent considerable revision with the favouredchoice being a bicycle arrangement supplemented by outrigger wheels.

There were al 0 attempts to design variouscrew capsule escape systems, but this wasconsidered too complicated and the ideawas finally abandoned. With concems aboutweight, Chadwick hoped to reduce the number of turbojets to two, assuming it becamepossible to build an engine with 20,OOOIb(89k ) static thrust. This twin-engine deltawing bomber continued to evolve and a fuselage began to form in the centre of the wingand protrude forward beyond the leadingedge, making it easier to produce a pres-urised crew compartment and allow extra

space for essential equipment. But it wasclear that two engines remained an unrealistic option and the Avro team eventuallya epted that four turbojets were necessary.

Modifications continued and the Type 698now featured upright wingtip fins with ruddersand four Bristol BE. 10 (later Olympus) turbojets arranged with two, staggered above theothers. Air intakes for upper and lower engineson each side of the aircraft were located oneach ide of the forward fuselage ection. On23 Augu t 1947, Roy Chadwick was being carried as an ob erver on the test flight of an AvroTudor II. Incorrect servicing of the ailerons

unusual crescent-shaped wing with decreasing sweep and decreasing chord, which wasintended to provide a constant limiting Machnumber across the entire wing at a highcruise speed. Based on early research by DrGustav Victor Lachmann (1896-1966), itwould become the Handley Page Victor. Inaddition to the chosen bomber designs, Vickers-Armstrong had been working on ideas forjet bombers since 1944 and submitted a proposal for OR.229. Their design was considered too con ervative and met with rejection,but the company's chief designer GeorgeEdwards managed to maintain interest in hisconcept and the Air Ministry finally decided toallow further development on the promise ofa prototype by 1951. Subsequently, Specification B.9/48 was issued and the Vickersbomber received the company designationType 660. onsidered as further insuranceagainst development problems with themore advanced Vulcan and Victor, this aircraft would become the Valiant.

However, prior to reaching the completiondate for OR.229, the design team at Avro considered everal ideas that differed considerably from the later Vulcan delta wingbomber. Heading the design office wasAvro's Technical Director Roy Chadwick(1893-1947) who created the Avro Lancasterand is now generally regarded as one ofBritain's greatest aircraft designers.

Initially, Chadwick envi aged a fairly conventional jet-powered bomber that was nottotally dissimilar to the Vickers-Armstrongproposal. It would have a streamlined fuselage, four jet engines buried in the wing rootand a conventional tailplane. Unfortunately,Chadwick contracted shingles in January1947 and had to leave the bomber project tohis design team who included Bob Lindley,

Stuart Davi s and Donald Wood.Influenced by the work that had been

undertaken in Germany by Alexander Lippisch on delta configurations, Chadwick'sdeputy Bob Lindley moved away from theearly outlines and began to draw up proposalsfor a bomber which was for all intents and purposes a flying wing with no vertical stabilisers.It would use a boundary layer control systemwith power provided by five centrally locatedAvon or Sapphire turbojets. The intake for thejet engines would be a large forward letterboxshaped duct at the front of the aircraft. One ofthe most intere ting features of thi particulardesign was the directional engine exhaust system using large upper and lower flaps.

The aircraft would be fitted with two separate cockpits and the forward section wascapable of tilting to provide better vi ibilityunder certain circumstan es. Lindley also

..... , ...11111111l)lJ

,,-- ".. ...I \1 ,

\ ..../\..../

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One of many early configurations for theadvanced post-war Avro jet bomber thatwould become the Vulcan. Bill Rose Collection

An unusual flying wing design producedduring early studies that would lead to theVulcan bomber. Bill Rose olleclion

cial requirement was issued on 7 January 1947known as Specification B.35/46. The companiesresponding to this request were quickly narrowed down to Avro, which developed a proposal called the Type 698, Handley Page with itHP.80 design and Armstrong Whitworth whichsuggested a tailless aircraft called the AW.56(see earlier description). Th AW.56 wasrejected, while a preliminary study undertakenby Avro's Project Office at Chadderton, Manchester, received enthusiastic support in officialcircles and was given the go-ahead.

Handley Page was also contracted todevelop the HP.80, which was seen as a fallback against failure of the Avro design. Theadvanced Handley Page proposal used an

Early Avro Vulcan Studies

In 1944, the Air Mini try produced a paper withthe title 'Future Bomber Requirements'. Thisoutlined idea for aircraft to follow the most successful types in service such as the Avro Lancaster. With the war over, there were newadversaries in the East and the RAF began toseriously consider ideas for an advanced, flveman strategic bomber powered by jet propulsion. This led to an Air Staff OperationalRequirement (OR) 229 being is ued in late 1946for a fast, high-altitude aircraft, capable of delivering an atomic bomb with an estimated weightof 10,000 Ib (4,535kg), to a target l,500nm (1726miles or 2,776km) distant. A more detailed offl-

26 Secrel Projects: Flying Wings and Tailless Aircraft British Tailless Aircraft 27

I (possibly 2)

75ft (22.86m)30ft 9in (9.37m)

CrewWingspan

(fully forward)(fully swept)

Aspect ratio(low speed) 10.7 (16.7 wing only)(swept) 1.88

Length 68ft 9in (20.95m)Height UnknownEmpty weight 14,5001b (6,577kg)Gross weight 25,0001b (II ,339kg)Fuel weight 9,0001b (4,082kg).Payload capacity 1,500 lb (680kg)Powerplant 4xBristol afterburning turbojetsEngine pod dimensions 34in x24ft (0.86m x7.3m)Maximum speed Mach 1.6Take-off speed 155mph (250kph)Landing speed 130mph (209kph)Cruise altitude 35-40,000ft (l0,668-12,192m)Ceiling 50,000ft (l5,240m).Range UnknownArmament None

Vickers Research Swallow 1958

wings fully forward and a wingspan of 30ft 9in(9.37m) fully swept. One noticeable difference between the manned aircraft and earlier models was the extension of the fuselagerearwards to house additional equipment,fuel or, in later versions, a military payload.Height of the aircraft is unclear, although it isknown that a substantial ground clearancewas considered necessary for take-offs andlandings. The undercarriage was to be amulti-wheel tricycle design with take-offspeed calculated at 155mph (250kph) andlandings made at 130mph (209kph). At lowspeed the Research Swallow would have an

This version of the variablegeometry Vickers ArmstrongSwallow was configured as anuclear strike aircraft. Roughlycomparable in size to theRockwell B-IB and manned bya crew of four or five, it wouldhave possessed a maximumspeed of Mach 2. Chris Gibson

I38ft (llo58m)46ft 6in (l4.17m)8ft 4in (205m)UnknownUnknown

CrewWingspanLengthHeightPowerplantPerformance

Heston JC.9

Armstrong wind tunnel. Then trials beganwith 10 models, each having full wingspans of30ft (9.lm) and wingtip fins and elevons. Themodels were built and issued with the serialsXK831-835 and XK850-854, with tests beginning at Predannack Aerodrome in 1955 andcontinued until the late 1950s. On one occasion, a model powered by two rocket motorsreached a speed of Mach 2.5, while fullydeveloped models with dummy engine podsunderwent supersonic tests in the wind tunnel at RAE Bedford. Although the Swallowwas not chosen for 0R.330, official interest inWallis' project was considerable. Vickerscontinued to receive financial support for theSwallow trials and serious discussions aboutbuilding two different manned research aircraft took place in 1957.

The initial proposal was for a small oneman demonstrator with an approximateweight of 10,000 Ib (4,535kg), which gave wayto a similar but larger aircraft with a grossweight of 25,0001b (I 1,339kg). This aircraftwould have a similar airframe to later production versions with a conventional forwardcockpit that accommodated a pilot and couldbe adapted for a second crew member.

The Research Swallow had a proposedlength of 68ft 9in (20.95m) with the wings fullyswept, a wingspan of 75ft (22.86m) with the

By 1951, Wallis was considering ideas for amanned variable geometry aircraft thatwould perform well across wide a range ofdifferent speeds and the next stage in his programme would be the construction of a smalldemonstrator. George Cornwall was the chiefdesigner for Heston Aircraft and his companywas heavily involved in the Wild Goose project as the main sub-contractor. Wallis haddrawn up proposals for a small manned variable geometry aircraft and Cornwall wasasked to finalise the design. A contract wasthen issued to Heston Aircraft leading to theconstruction of a prototype which receivedthe designation lC.9.

The single-seat lC.9 was 46ft 6in (I 4.1 m) inlength with a maximum wingspan of 38ft(I 1.58m) and a height of 8ft 4in (2.5m). It wasfitted with a retractable tricycle undercarriage and appears to have been intended foruse as a glider with the possibility of installinga turbojet later. In appearance, the lC.9 wasquite unusual having a bulbous rear fuselagewhich tapered towards the nose and a singleswept, vertical tailfin. It was built in sectionsand transported to Weybridge for finalassembly where it remained uncompleted ina hangar for some time until the lC.9 wasfinally scrapped. Exactly why this happenedremains unknown, although there is someconjecture that Barnes Wallis was 'encouraged' to have this aircraft built despite hisstrong opposition to the manned tests of newprototypes. Could it be that he delayed the aircraft's construction until it was no longerrequired?

Before the Wild Goose trials ended in 1954,Wallis had started to work on the design of ahigh-performance variable-geometry taillessaircraft that might be developed to fly intercontinental distances. At the same time, theRAF was beginning to consideJ ideas for afuture high flying supersonic reconnaissancebomber and 0R.330 was issued. Vickers wasnot approached to submit a design for this aircraft, but Wallis obtained a copy of 0R.330and adapted his variable geometry concept tomeet this need. He envisaged a sleek arrowshaped tailless aircraft with a flattened profileand variable geometry wings pivoted towardsthe rear of the fuselage, using a form ofknuckle joint. Engines in pods would bemounted towards the wingtips which wouldswivel and also be adjustable in pitch. Thiswould allow the propulsive system to takeover from conventional control surfaces.Position of the engines was also important forminimising centre of gravity problems as thewing angle altered.

Small models of Wallis' new design calledSwallow were initially tested in the Vickers

research. The Wild Goose models would beflown initially as gliders and controlled usingrather basic radio equipment. This presentedmany challenges to Wallis' team as separateoperators were required for pitch and roll.The models remained fairly stable in flightwith the team graduating to powered testsusing rocket propulsion. The National Physical Laboratory at Teddington, Middlesex, wasalso conducting wind tunnel tests on WildGoose models and there was official interestin using this research to develop a new surface-to-air missile. The first really successfulflight of a Wild Goose test vehicle took placein April 1952, although the model was writtenoff in crash soon afterwards. The Wild Goosetrials continued until late 1954 when it wasrealised that laminar flow was unattainable.

However, much of this research was beingsupported by a classified weapons systemcalled Green Lizard which would comprise acompact missile fired from a launch tube.Early designs began soon after the end ofWorld War 2, with several patent applicationsbeing made in 1949 and held unpublisheduntil 1956. The design was considered as asurface-to-surface and surface-to-air missile,eventually becoming a turbojet-powered Mmissile that was equipped with flip-out sweptwings. It would be based around the BritishIsles to protect against Soviet bombers and,when used, it would dispense 100 sub-munitions in the path of attacking bombers. Workon this project was abandoned in the early1950s, but some design features can be seenon current air-launched weapons.

This drawing from a 1964 UK Patent (GB950400)shows the internal system of rotary adjustmentfor the Swallow's wings. UK Patents Office

The proposed Vickers Swallow supersonic nuclearstrike aircraft in RAF markings and anti-flash whitefinish. Bill Rose Collection

General layout of the SwallowResearch Aircraft. Chris Gibson

trolley on rails at 100mph (I60kph). Thesemodels comprised slender, smooth ovoidbodies with aft mounted variable sweepwings and a highly swept tail fin.

Vickers had been awarded a half millionpound contract for supersonic tests as part ofthe abandoned M.52 project and the moneywas now reallocated for Wallis' project thathad been called Wild Goose. It would utilisemodels for wind tunnel and flight-testing. Inaddition to the wind tunnel models, 12 largerWild Goose test vehicles were built andissued with serials XA197-202 and XA947-952.The models were slender with the wingsmounted towards the rear and the vehiclewas equipped with a single upright tailfin.There was also provision to fit a small rocketmotor as the trials progressed.

In late 1949, flight tests began at Predannack Aerodrome near the Lizard in Cornwalland considerable secrecy surrounded theproject which was regarded as pure military

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was completed, Wallis returned to designingmassive ground-penetrating bombs such asthe Tallboy (I 2,000 Ib - 5.44 metric tons) andthe even bigger Grand Slam (22,000Ib - 9.9metric tons) which were used with considerable success against special targets such asrocket launching facilities, the German battleship Tirpitz and massively hardenedU-Boat pens.

Towards the end of World War 2, BarnesWallis began to take an interest in the possibility of supersonic flight and considered theidea of a tailless aircraft with movable wings.In 1946, he wrote a technical paper entitled'The Application of the Aerodynamic Properties of Three Dimensional Bodies to the Stabilisation and Control ofAerodynes'. This wasfollowed by work on the design of a flyingmodel that would provide useful data on theuse of laminar flow techniques. Starting withsmall hand-launched models, Wallis progressed to larger versions, propelled from a

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sonic speed wasted about half the fuelrequired to maintain level flight through dragat the boundary layer. But an effective andreliable system of control remained elusive.In the post-war years, the US Navy tested various boundary layer control methods with amodified Cessna 170 and a Grumman Panther jet fighter, while the USAF sponsoredtests conducted at Edwards AFB, using anadapted F-84 fighter.

The RAE at Farnborough was using theAW.52 flying wing for BLC trials, althoughresults proved disappointing and the projectwas abandoned in 1953. evertheless, someresearch continued at Handley Page's Radlettfacility under the direction of the company'schief aerodynamicist Dr Gustav Lachmannand his deputy Godfrey H. Lee. Mainly fundedby the Ministry of Supply, this took the form ofwind tunnel testing and airborne trials usingthe prototype DH.113 Vampire fighter.

Certain aspects of this research had militaryimplications and were classified, but manydetails found their way into the public domainwith Dr Lachmann outlining his project to theRoyal Aeronautical Society on 11 November1954. By 1956, Lachmann was hoping toutilise BLC methods with a fairly conventionalaircraft design, which initially looked like a deHavilland Comet and steadily evolved into anairliner resembling the Boeing 707.

Lachmann and Lee then concluded that anentirely new kind of aircraft was required for

HP.117 Flying Wing Studies

The flying wing project described in this section was another attempt to exploit boundarylayer reduction which is theoretically wellsuited to this type of aircraft. The designershoped to develop an advanced transport aircraft that was primarily aimed at the commercial sector with secondary military aircraft.

Boundary Layer Theory (BLT) can betraced back to the beginning of the 20th century and it is generally attributed to the German scientist Ludwig PrandtI. Many sourcesalso acknowledge concurrent researchundertaken in England by Frederick WilliamLanchester and it is quite common to find references to Lanchester-Prandtl TheOly. However, it was some years before anyone was ina position to experiment with boundary layercontrol (BLC) and the first practical testswere undertaken in 1936 by the Swiss aerodynamicist Dr Werner Pfenninger, working atthe Institute for Aerodynamics in Zurich.

In 1939, NACA Langley conducted someelementary BLC experiments using suctionslots, but the programme ended after the USjoined the war, with the focus of attentionswitching to the perfection of laminar flowaerofoils. At about the same time, Miles Aircraft in Britain carried out similar trials andscientists in Germany experimented withBLC, using a modified Me 109. Aerodynamicists recognised that an aircraft flying at sub-

Vickers High/Low Level Bomber/ Vickers Military Transport Swallow/Naval Strike Swallow Vickers Swallow Fighter Long Range Bomber

Crew 1-2 Crew Crew 4-5?Wingspan Wingspan Wingspan

(Fully forward) 75f1 (2286m) (Fully forward) 75f1 (2286m) (open) 174f1 (53m)(fully swept) 30fl9in (937m) (Fully swept) 30fl9in (937m) (folded) 71 fl6in (2179m)

Aspect ratio Aspect ratio Aspect ratio(low speed) 107 (16.7 wing only) (low speed) 10.7 (16.7 wing only) (low speed) 10.7 (16.7 wing only)(swept) 188 (swept) 188 (swept) 188

Overall length 68f19in (20 95m) Height Unknown Overall length (swept) 160fl (48.76m)Height Unknown Overall length 68f19in (20 95m) Height UnknownEmpty weight 16, I00 Ib (7,302kg) Empty weight 15,2501b (6,917kg) Gross weight 150,000 Ib (68,038kg)Gross weight 30,000 Ib (l3,607kg) Gross weight 30,000 Ib (13,607kg) Landing weight 95,750 Ib (43,431 kg)Fuel weight 12,250 Ib (5,556kg) Fuel weight 13,220 Ib (5,996kg) Fuel weight 58,750 Ib (26,648kg)Powerplant 4x Bristol aflerburning turbojets Payload capacity 1,530 Ib (680kg) Powerplant 4xaflerburning turbojets,Engine pod dimensions 34in x 24f1 (0.86m x 73m) Powerplant 4x Bristol aflerburning each producing 12,850 Ib (57kN)Maximum speed Orpheus turbojets static thrust(high Level) Mach 2 Maximum speed Mach 2.5 Engine pod dimensions 40in x30fl (I mx9m)(low Level) Mach 0.95 Take-off speed I72mph (276kph) Payload capacity 25,000 Ib (II ,339kg)

Take-off speed I72mph (276kph) Landing speed 130mph (209kph) Maximum speed Mach 2.5Landing speed 130mph (209kph) Cruise altitude 40,000FI (12, 192m) Take-off speed 164mph (263kph)Cruise altitude 36,000ft (I 0,972m) Ceiling 80,000FI (24384m) Landing speed 131mph (2 IOkph)Ceiling 80,000FI (24,382m) Improvised tactical airstrip Cruise altitude 67,000FI (20,42Im)Range Unknown take-off distance 3,000FI (914m) loaded Range 4,600 miles (7,400km)Payload capacity 1,500-2,000 Ib (680-907kg) Range 1,500 miles (2,414km) estimated Armament One, possibly two free fallArmament Single tactical nuclear weapon Armament AAMs nuclear weapons

that development of the Swallow would takeat least 10 years to complete. Unfortunately,1957 was the year of the infamous DuncanSandys' White Paper that suggested that theera of manned military aircraft was drawingto a close. As a direct consequence, manyadvanced programmes were terminated.Further official funding for the Swallow wascut and Wallis was allowed to approach theAmerican Mutual Weapons DevelopmentProgramme (MWDP) Office in Paris for help.This led to a US team visiting Weybridge anda small delegation led by Wallis visiting NASAat Langley.

All the Swallow research data was thenpassed to the US and although a six-monthjoint US-UK development programme wasdiscussed with MWDP staff, much of theresearch was undertaken at Langley.

By June 1959, NASA was reporting lift/dragratio and pitch-up problems with the Swallowdesign and it was angling to use the variablegeometry design for an entirely differenttailed design. Wallis' concept was effectivelydead, although a good deal of the researchundertaken during the Swallow programmewould find its way into the future F-Ill swingwing bomber. The Swallow was a superblooking proposal and still seems futuristictoday. It is interesting to speculate onwhether this very complex design could havebeen developed into an operational militaryaircraft had sufficient funding been available.

some structural strengthening and modifications for the latter. The most likely choice ofpropulsion for the Strike-Swallow was fourafterburning Bristol Siddeley BE.38 turbojetengines. The BE.38 was a proposed high-performance variant of the Orpheus engine, butit was never completed.

The fighter version of the Swallow was similar in many respects, although the maximumspeed quoted was Mach 2.5 and a realisticrange might have been approximately 1,500miles (2,414km), although some documentation suggests substantially more allowing foreconomic cruise. Armament is unknown, butit seems probable that two or four air-to-airmissiles would be carried externally.

Several larger variable geometry versionsof the Swallow were proposed that includeda bomber with an overall length (at full 80°wing sweep) of approximately 130ft (39.6m)and a wingspan (with the wings fullyextended) of about 130ft (39.6m), making itquite close in size to the Rockwell B-1 B variable geometry bomber. This version of theSwallow would probably have carried a crewof 4-5 and posses a maximum speed of aboutMach 2. The payload would have been a single nuclear weapon ejected rearward fromthe extended tail section.

As a supersonic military transport aircraft,Wallis proposed a version of the Swallowwith an overall length (with full wing sweep)of 160ft (48. 76m), a fully extended wingspanof 174ft (53m) and a fully swept wingspan of71ft 6in (21.8m). It would have exactly thesame aspect ratios as the smaller designs.The aircraft would utilise a multi-wheeled tricycle undercarriage layout with a substantialground clearance of about 20ft (6m), considered necessary during take-off and landing.Its gross weight was set at 150,0001b(68,038kg) with a maximum speed of Mach2.5 and a cruise altitude of 67,000ft(20,421 m). Operation range would be 4,600miles (7,400km) and the payload capabilitywould be 25,0001b (ll,339kg). Powered byfour engines in wing-mounted nacelles, thesize of each unit would suggest that Walliswas considering a choice of several differentafterburning turbojets.

While this aircraft was envisaged for military use, Wallis also considered the idea of aslightly smaller commercial supercruise airliner, capable of carrying 60 passengers toAustralia without any refuelling stops.

A further variant of the airliner would useeight turbojets mounted in individual wingpods. Various ideas were studied for cockpitlayouts that included a rising capsule thatwould allow improved visibility at lowspeeds. Nevertheless, it was now recognised

A proposal for a VickersArmstrong supersonic Swallowfighter equipped with twoexternal air-to-air missiles.Chris Gibson

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A number of Swallow variantswere considered, including thisproposal for a long-range airlineror military transport aircraft witha Mach 2.5 capability. Cruising atan altitude of 67,000ft (20,421 m),this design would have had anun-refuelled range of about 4,600miles (7,400km). Chris Gibson

. .

As a bomber, the Swallow would have amaximum performance of Mach 2 at a typicalaltitude of 36,000ft (J 0,972m). In the low levelrole, it would have a maximum speed ofMach 0.95 at an altitude of 500ft (152m). Theservice ceiling would be 80,000ft (24,382m).Gross weight was estimated at 30,0001b(13,607kg) and a payload was probably a single rearward-ejected free-fall nuclear bombin the Red Beard (J 5 kiloton yield) class. It ishard to see this aircraft being considered forthe delivery of conventional ordnance. Rangefor the bomber is thought to have been about5,000 miles (8,000km). This variant would becapable of operating from an improvised tactical airstrip such as a good stretch of straightadequately wide roadway, or the deck of anaircraft carrier, although it would require

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aspect ratio of 10.7 and this would alter to 1.88fully swept. Wingtip stabilising fins were alsoproposed. Empty, the aircraft would weigh14,5001b (6,577kg) and the additional fuelweight would be 9,000 Ib (4,082kg).

Four Bristol turbojet engines with afterburners would be housed in wing pods measuring34in (863mm) in diameter and 24ft (7.3m) inlength. Suggested maximum speed was Mach1.6 with a cruise altitude of 35-40,000ft (J 0,66812,192m) and a ceiling of about 50,000ft(15,240m). Developed into a military aircraft,the Swallow would have the same overalldimensions as the Research prototype. Twodifferent variants were proposed for the RAFand the Royal avy. The first was a high/lowlevel bomber or naval strike aircraft and thesecond was a high performance fighter.


I45ft 4in (138m)221ft' (20 58m')50ft 2in (15.2m)15ft 6in (4.72m)10,7401b (4,871 kg)I xBristol·Siddeley Orpheus BOr.3Mk.805 turbojet, producing 4,000 Ib(I 779kN) static thrustUnknown, although the H.126 wasdesigned to explore low speedand could fly at 32mph (51.5kph)Unknown

3flight 2cabin50ft (15.24m)1,240ft'(115m')57ft (l7.37m)15ft (4.57m)64,000 Ib (29,030kg)444mph (716kph)4x turbofan engines100 pas engers (as an airliner)

A proposed layout for the Aerobus jet-flaptransport aircraft. Bill Rose Collection

Hunting Aircraft H.126

CrewWingspanWing areaLengthHeightGross weightPowerplant

Maximum peed

Ceiling

Aerobus (I 962 proposal)

CrewWingspanWing areaLengthHeightGross weightCruise speedPowerplantPayload

speed control and the remainder wasexhausted on each side of the lower fuselage.

The H.126 was a compact, single-seat aircraft, built around its turbojet engine. Thecockpit was located in a forward position,offering good visibility and the tricycle undercarriage was of a simple, fixed positiondesign. Trials were mainly undertaken at RAEBedford between 1963 and 1967 with no serious problems occurring and the aircraft wasthen loaned to NASA who conducted windtunnel tests at the Ames Flight Research Center during 1969. H.126 was returned the following year and is now on display at the RAFCosford Museum.

The jet nap experiments showed that theidea could be made to work, but it alsobecame apparent that the nozzle system wastoo complex to be practical and the powerrequirements were much greater than originallyanticipated.

A related, although much simpler systemusing air ducted from the compressor stage,was utilised by several !960s combat aircraftto improve low speed performance. This'blown nap' can be found on several currentmilitary transport aircraft.

recognised that a wing capable of vectoring ajet now along most of its trailing edge wouldpresent various engineering problems. Therewas also the matter of how to maintain controlin the event of an engine failure. At cruisingspeed, an aircraft using jet naps would behavelike a conventional fixed wing design, but atlower speeds the jet now would be directeddownwards, generating considerable lift andproviding outstanding STOL performance.

The research programme continued withIvor Davidson presenting an outline of jet napdevelopment to the Royal Aeronautical Society in October 1955. But it was now becomingclear that this technology would be difficult touse with the majority of existing fixed wingdesigns and he realised that a new type of aircraft was needed.

By the end of the 1950s, Davidson had outlined a compact transport aircraft called Aerobus that would take advantage of laminarnow aerodynamics and use the jet nap system. This all-wing design would have awingspan of 50ft (15.24m), a wing area ofI ,240ft' (l15m') and a length of 57ft (17.37m).The aircraft would be supported on theground by a retractable tricycle undercarriageand the gross weight (as an airliner) was estimated at 64,000 Ib (29,030kg) with the anticipated payload being 100 passengers and theirluggage. Propulsion would be provided by atotal of four turbojets in wingtip nacelles connected to 16 trailing edge outlets via ducting.This short-haul aircraft would cruise atapproximately 444mph (716kph) with anoperating altitude of 20,000ft (6,096m). TheAerobus project continued into the early1960s with the operating cost initially estimated at 1.2 pence (old) per passenger mile.

Despite limited commercial and militaryinterest in Aerobus, the State-funded GTEcontinued to develop jet nap technology, having already requested the construction of aproof-of-concept aircraft during the late 1950s.

This received Ministry of Aviation approvaland Hunting Aircraft of Luton, Bedfordshire,was issued with a contract in June 1959 tobuild two small demonstrators. The first prototype known as H.126 (serial XN714) undertook its maiden night at RAE Bedford on 26March 1963 with Hunting's Chief Test PilotStanley Oliver at the controls. By this time, thesecond prototype was considered unnecessary and had been cancelled.

The jet nap system used on the H.126 consisted of 16 nozzles located along the wing'strailing edge, releasing approximately half ofthe jet engine's exhaust gas. A small amountof gas was also ducted to the wingtips for low

The Hunting H.126 prototype. BAE Systems

Davidson's Aerobus

encouraging, Lachmann and Lee continuedto evolve their design for the HP.1!7 as a 300seat airliner. It would now have a wingspan of148ft (45m) and be powered by four or sixRolls-Royce turbofans with the gross weightreaching 330,0001b (149,685kg) and an estimated range of 5,000 miles (8,000km).

Although there was a reluctance to continue spending government money on thisHandley Page programme, the Ministry of Aviation agreed in 1963 to follow the researchtaking place at Cranfield with trials of a testwing fitted to a Hawker Siddeley HS.125 transport jet. Continuing development of theHP.lI7 led to a somewhat different design fora very substantial military transport designated HP.135, which was displayed in modelform, but failed to attract the kind of interestrequired for further development. In 1965,

Lachmann retired and one year later was sadlydead. So was the HP.117 project. Work onboundary layer control was now at a standstillin Britain and the X-2IA trials concluded in theUS at about the same time. Northrop showedthat boundary layer reduction could be madeto work, but many of the previously identifiedproblems remained unresolved. In the 1980s,there was a revival of US interest with trialsinvolving an F-III and F-14 flown from Dryden,later followed by supersonic experiments withthe F-16XL. However, at the present time, anapplication of this technology remains elusive.

1952 saw the beginning of a project atBritain's National Gas Turbine Establishment(NGTE) to utilise a system of directing a jetnow through a wing's trailing edge to improvelow-speed performance. The idea was notentirely new and the German aerodynamicists H. Hagedorn and P. Ruden had notedinteresting trailing edge effects during boundary layer control research in 1938.

After examining the data from these windtunnel tests, scientists at NGTE undertooksome very elementary experiments withsmall desktop-sized models. This indicatedthat increased lift and thrust might beachieved by ducting a certain amount of jetengine exhaust to the wing's trailing edge.A thin jet sheet produced behind an aircraftcould be used in much the same manner asa hinged wing nap, leading to the term 'jetnap'. There were various ways the jet nowmight be directed that included long slots,nozzles and naps positioned in the jet now.

Heading the NGTE jet nap project was IvorDavidson who soon began to consider practical uses for this technology, although he

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One of the HP.117 proposalsproduced by Lachmann and Lee inthe late 1950s. Bill Rose Collection

official support for his research, which wouldresult in the development and testing of ahighly modified Folland Midge wing with a45° sweep. This was mounted in an uprightposition on the dorsal section of an Avro Lancaster (PA474) which belonged to the College of Aeronautics at Cranfield. The first testwas considerably delayed and did not takeplace until 2 October 1962.

The new aircraft proposed by Lachmannand Lee was assigned the company reference HP.117 and the first rather loose set ofdesigns was completed by April 1959. Theirconcept took the form of a swept nying wingwith wingtip stabilising fins, although variousoptions were reviewed for different performance and payload requirements. Three tosix turbofan engines would power the HP.117and a pusher turboprop arrangement wasconsidered at one stage, but found unsatisfactory. The HP.117 would accommodate 200to 300 passengers and it was finally decidedthat the ideal wingspan was 125ft (38m) witha sweep of 44° at mid-chord.

A scale model of HP.1!7 was exhibited at LeBourget in 196! with claims to the media thatthis design could reduce transatlantic fares byas much as 30 per cent and make long distance travel a reality for many ordinary people.Progress with the project remained sluggishand although Lachmann met with representatives of the Ministry of Aviation during 196!, hefailed to secure any financial support for theconstruction of prototypes once the wing trialsat Cranfield had been completed.

Lachmann wanted to start with the conversion of a Victor bomber for use as a test bedand if this aircraft performed well with theboundary layer reduction system installed, itwould be followed by the construction of twoscale size demonstrators based on the HP.!17,which would be designated HP.119. Althoughthe response from the ministry was less than

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4·6 (plus 200 passengers)125Ft (38m)44' at mid chord5,820Ft' (540m')101 Ft (30.78m)42Ft (128m)527mph (848kph)55,000Ft (16,764m)5,000 mile (8,046km)330,0001b (149,685kg) laterrevised to 305,0001b (138,345kg)3or 4Rolls·Royce RB 163 turbofans

244Ft 8in (136m)50'30,000 Ib (13,607kg)3Bristol Siddeley Viper BSV.20turbojets, each rated at 3,000 Ib(l3.3kN) static thrust Two enginesfor propulsion, the third to drawoff air from the boundary layer.6,700 miles (I O,OOOkm) at 527mph(848kph) at 40,000Ft (12, 192m)

HP.1l7

this project and a nying wing was the optimalshape for a long-range transport aircraft making full use of boundary layer reduction methods. By 1958, both the RAE and NACA hadgenerally lost interest in BLC, although workcontinued at Northrop under the direction ofDr Werner Pfenninger who had beenrecruited by Jack Northrop in the late 1940s.

This ongoing research was enough to keepthe Handley Page programme alive, especially with Northrop preparing to constructthree X-21A research aircraft which hadstarted life as Douglas WB-66Ds. Subsequently, Lachmann managed to maintain

HP.1l9

CrewWingspanSweepWing areaLengthHeightCruise speedCeilingRangeGross weight

Powerplant

CrewWingspanSweepGross weightPowerplant

Range


---Arado's Ar 555-1 six-engine jet bomberdesign. Many alternative versions wereconsidered, but the project was abandonedin December 1944 with priority beingswitched to fighter development.Bill Rose Collection

Built almost entirely from steel and duralumin, E.555-1 would be powered by six BMW003A turbojets, each providing a maximumstatic thrust of 1,7601b (7.8kN). The aircraftwould have a wingspan of 69ft 6~in (21.2m)with a wing area of 1,345.5ft' (125m'). Theoverall length was approximately 60ft (18m)and the height was calculated at 16ft 4in(5m). Two substantial vertical stabilising finswith rudders would be fitted and the anticipated gross take-off weight was 52,9111b(24,000kg) with a payload of 8,8181b(4,OOOkg) payload. Maximum speed at altitude was expected to be 534mph (860kph)with an economic cruise speed of 444mph(714kph) and a ceiling of almost 50,000ft(15,240m). A crew of three would be accommodated in a fully pressurised cockpit andthe aircraft would be supported on theground by a tricycle undercarriage. It was alsosuggested that a 'jettisonable' take-off trolleymight be used (possibly with rocket assistance) to improve range when carrying a fullpayload and E.555-1 could be equipped withextra internal fuel tanks. Defensive armamentwould comprise two fixed forward-firing30mm Mk103 cannons, plus a remotely-controlled tail turret with two 20mm MG151/20cannon and a remotely controlled dorsal turret also fitted with two 20mm MG 151/20 cannons. The turrets would be controlled from apressurised cabin behind the main crewcompartment with the operator using aperiscope system.

The operational range of this aircraftremained a major issue and attacking distanttargets meant that there would be little or noloiter time available in the bombing area, so

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(5,000km). Although the request for a newlong-range bomber had yet to be officiallyissued, Arado was already at the forefront ofjet bomber development and had receivedadvanced warning of what was likely to berequired in the coming months. They nowhoped to utilise a flying wing design with alaminar high-speed profile to provide theexpected level of performance.

Under the leadership of Arado's Dr W.Laute, 15 different concepts were developedfrom research undertaken by Dip!. Ing. Kosinand Lehmann who had produced a studycalled 'Flying Wing Aircraft for Long-Rangesand High Speeds'. Laute's new study wasdesignated E.555 (the E prefix signifiesEntwurf - Draft Project) and the variationsbecame E.555-1 to E.555-15. In most cases,the main difference between each designwas the number of engines, their locationsand minor variations in wingspan or length,but the possibility of extending the fuselagerearwards or utilising tail booms was alsoconsidered. All available jet engines werereviewed during the study and included theBMWI09 003, Junkers Jumo 004 and HeinkelHirth He S 011, which would be housed inexternal nacelles.

The initial studies were completed in early1944 and a meeting between Arado representatives and the RLM took place on 20 April1944. Details of the new flying wing bomberwere then informally finalised. Within a matter of weeks, a decision had been taken toproceed with further refinement of the AradoE.555-I, which was intended for use againsttargets on America's Eastern Seaboard anddeep within Russia.

369ft 6~in (212m)60ft (I8m)16ft 4in (5m)1,345.5ft' (I 25m')534mph (860km/h)50,OOOft (15,240m)2,982 milest (4,800kmt)52,9111b (24,OOOkg)Six BMW003A turbojets, eachproviding amaximum static thrustof 1,760 Ib (7.8kN)Two fixed forward mountedMk I03 30mm cannons,two MG 151/20 20mm in tail turretand two MG151/20 20mm cannonsin dorsal turret8,8181b (4,OOOkg)

Armament

Arado Ar E.555-1

CrewWingspanLengthHeightWing areaMaximum speedCeilingMaximum range'Take-off weightPowerplant

Towards the end of 1943, the design office ofArado Flugzeugwerke GmbH at Landeshut inSilesia (now Kamienna G6ra in Poland)began work on a highly advanced flying wingjet-powered bomber, intended to meet futurerequirements of the Reichsluftfahrtsministerium (RLM - German Air Ministry). Theobjective was to develop an aircraft capableof delivering a payload of at least 8,8181b(4,OOOkg) over a range of at least 3,100 miles

Arado Flying Wing Projects

his first full-sized delta wing design wascalled Delta I. A series of aircraft developedfrom the Storch and Delta followed, with Lippisch eventually vacating his position with theDFS to join Messerschmitt in 1939 where heworked on a rocket powered tailless aircraft.

As World War 2 progressed, German aircraft designers became increasingly convinced that jet and rocket powered taillessdesigns represented the next generation ofhigh-performance warplanes. Most of themajor aircraft manufacturers produced tailless proposals, with many being tested aswind tunnel models. Only a few reached theearly stages of construction. Had the wartaken a different course and lasted longer, itis a certainty that some of these impressivedesigns would have entered operational service. Indeed, once hostilities ceased, theAllies wasted no time securing German aircraft research documentation and equipment while making every effort to track downthose scientists and engineers who hadworked on the most advanced projects.

*With supplementary fuel tanks and full bomb load

Bomb load

in 1929 and became the world's largest landbased aircraft. At the beginning of the 1930s,Reimar Horten (1915-1994) and his olderbrother Walter (1903-1998) started work ontheir first tailless glider called the Ho I. Apparently, this project received their parents' fullsupport and some of the construction tookplace in their dining room.

The Ho 1 was followed by the H02 in 1934and during the following year was upgradedby the addition of an 80hp (59kW) HirthHM60R engine connected to a rear mountedpusher propeller with a drive shaft. This aircraft was flown by the well-known test pilotHanna Reitsch (1912-1979) on 17 November1938, who was quite critical of the design.Nevertheless, her involvement with the project was sufficient to encourage the construction of a larger design called the H03 andit would eventually secure official government interest that would lead to the mostsophisticated experimental aircraft producedduring World War 2.

Another early aviation pioneer was Alexander Martin Lippisch (1894-1976) who witnessed a demonstration flight by OrvilleWright at Berlin in September 1909. Thisexperience made a lasting impression on the14-year-old Lippisch and, having served in theLuftstreitkrafte (Imperial German Army AirService) during World War 1 (as an aerialphotographer), he then secured a job withZeppelin and later Dornier as an aeronauticaldesigner. During his spare time, Lippisch produced plans for gliders and the well-knownglider pilot Gottlob Espenlaub built a fullsized aircraft from one of his designs in 1921.This would be followed by dozens of differenttailless designs and by 1925, Alexander Lippisch had become Director of the TechnicalDepartment at the RhOn-Ros ittenGesellschaft (RRG), which later became theGerman Research Institute for Soaring Flight(Deutsche Forschungsanstalt fur Segelflug DFS).

Lippisch now began work on his first powered aircraft called 'Storch' (Stork) andundertook development of the delta wing. Heis credited with coining the term 'delta' forthis type of aircraft, having taken it from thethree-sided Greek letter and not surprisingly,

Chapter Two

German World War 2Flying Wing Development

wing aircraft that represented a significantadvance in aviation design. Known as a Nurflugel (wing only) aircraft, Junkers recognised the advantages of housing crew,engines and payload within the wing. Oncethe design had been registered, Junkersestablished an aircraft design bureau at hiswater heater factory in Dessau and this led tosmall-scale manufacturing.

Although the Nurflugel was too far ahead ofits time to be built, Junkers began to producetechnical innovations that found their wayinto conventional aircraft, such as all-metalconstruction. World War 1gave the companya significant boost with Junkers building hundreds of warplanes in association withFokker and becoming established as a majormanufacturer. In 1924, Junkers producedplans for a giant airliner capable of canying100 passengers over long distances, but it wastoo advanced for practical development. Butsome elements of this concept were used inthe Junkers G.38 transport aircraft which flew

A classic Horten design, the Ho Ille Motorgliderwas powered by a Volkswagen engine and wasflown during 1944. Peter ash Coli clion

Dr Alexander Lippisch, one of the most influentialaircraft designers of the 20th century, photographedafter World War 2. Bill Rose Collection

German interest in flying wings and taillessaircraft pre-dates powered night, althoughthe most important early designer to set outspecific rules for this type of aircraft was HugoJunkers (1859-1935) who had spent the firsthalf of his life working as a very successfulheating appliance design engineer. Duringhis spare time, Junkers developed advancedaircraft concepts and in February 1910, hefiled a Patent (253788) for a powered flying

34 Secret Projects: Flying Wings and Tailless Aircraft German World War 2 Flying Wing Development 35

I31ft 2in (9.5m)30'30ft 2in (9.2m)11ft 4in (3.45m)9,I381b (4,1 44kg)I I,033 Ib (5,OO4kg)I x liquid cooled Daimler Benz12-cylinder DB603L engine,utilising atwo-stage uperchargerand methanol-water injection490mph (78 kph)760 miles (l,223km)3x30mm MkI08 cannons

BV P.208-3

Maximum peedRangeArmament

CrewWingspanweep

LengthHeightEmpty weightGro sweightPowerplant

While wind tunnel models of the P.208were being tested, a twin-boom, single seatSkoda-Kauba SK V-6 (itself a prototyp aircraft designed by Austrian engineer OttoKauba) was requisitioned and extensivelymodified to validate the Arrow Wing concept.The pusher propeller design made the SK V-6particularly suitable for these experimentsand the extensively modified aircraft, nowminus its original tail unit, was redesignatedas the SK SL6. Very little information is available for this test programme, which may havebeen undertaken at Prague. On 30 April 1945,almost all docum ntation relating to SkodaKauba Flugzeugbau projects was burnt andOtto Kauba made a swift exit from the city. Itis not thought that any of the Skoda-Kaubaprototypes survived the war.

However, it is understood that test nightshad started in late 1944 and may have ontinued into early 1945, demonstrating the viability of the unusual Blohm und Voss concept.Vogt now began working on the P.209, amore sophisticated Arrow Wing fight rdesign with a fuselage built around a Heink IHe SOIl turbojet engine drawing air from aforward no e intake. The aircraft would beequipped with a tricycle undercarriage andarmed with two 30mm Mk I 08 cannon in thelower forward fuselage. sing a similardesign of wing and control surfaces, th P.209was slightly more compact than the P.208with a wing pan of 35ft (10.66m) and anincreased sweep of 35°. Maximum speed wasestimated at 559mph (900km).

The next design in this series was the P.21 0oI, which Vogt entered for the 1944 Volksjager(People's fighter) competition. Thi wa theRLM's attempt to obtain a lightweight, relatively inexpensive jet fighter that could be produced by a semi-skilled workforce atdispersed sites. The single-seat P.21 0-01 wasvery similar to the P.209 in overall design, utilising a central tubular spar that formed the

Blohm und VossFlying Wing Projects

The Blohm und Voss Shipbuilding Companywas established in 1877 at Hamburg, Germany,and it produced many famous vessels includingthe battleship Bismarck. In 1933, the companyturned its attention to aircraft, becoming wellknown as a constructor of nying boats. Accompanying this move into the realm of aviationwa the recruitment of Dr Richard Vogt (18941979) who was appointed as the company'schief designer and i now remembered forsome of his highly unorthodox concepts thatreached the prototype stage in a few instances.

In late 1943, Vogt began work on a series ofideas for a new lightweight interceptor, initially using a rear-mounted Argus, Junkers orDaimler Benz piston engine driving a pusherpropeller. As the study evolved, Vogt developed this design into a turbojet-poweredinterceptor to meet the Luftwaffe's futureneeds. Despite heading the design office,Vogt undertook much of the work himself,with assistance from Hans Amtmann and thecompany's aerodynamicists, George Haagand Richard Schubert. The initial proposalsbegan to emerge in autumn 1944 with the reference P.208, which was generally knownwithin the company as the 'Arrow Wing'.

A a starting point, Vogt had taken somefeature from his earlier P.207 design for astraight-winged fighter with a rear-mountedthree-blade propeller. Keeping most of thefuselage section, he then dispensed with thetraight wing and tail control urfaces, fitting

a new 30° swept wing with a constant crosssection and tip-mounted down-turned control fins. There were several objectives for thisdesign and Vogt saw potential for improvingmaximum speed by minimising surface areaand reducing weight. The simple all-metalconstruction would also help to bring downthe cost of manufacturing the aircraft.

The P.208 project had started out with theintention of evolving quite quickly towards turbojet propulsion, but there were endlessdelay with the jet engines, so priority wasgiven to refining the aerodynamics. The firstthree studie for the P.208 only differed inengine installation, utilising the Jumo 222E,Argus AS413 or Daimler Benz DB603L. TheP.208-3 was then selected, which used the liquid-cooled Daimler Benz 12-cylinder DB603Lengine, equipped with a two- tage supercharger and methanol-water injection. Thisprototype engine was expected to provide amaximum (sea level) power output of 2,761 hp(2,059kW) at 3,OOOrpm. The engine's air intakeand radiator was positioned on the under ideof the fuselage, directly below the cockpit.

2or360ft 4in 18.40m807ft' (75.0m')35' (leading edge)4.5: I42ft 6in 12.95m12ft 6in (3.80m)20,5021b (9,300kg)34,6121b (I5,700kg)2x Heinkel He SOIIA turbojets,each rated at2,8651b (I 275kN)tatic thru t, or 2xBMW003A

turbojets, each rated at 1,760 Ib(7.8k ) static thrust503mph (8IOkph)2h 36m at economic cruise42,000ft (I2,800m)2or 4x30mm Mk213 cannon,forward firing; 2x30mm Mk213cannon, rearward firing; 2x30mmMk213 cannon firing upwardsfrom the centre of the aircraflIn the ground attack role:2x I, I021b (500kg) bombs

I29ft 2~in (8.95m)45' (leading edge)263ft' (24.5m')18ft 6in (5.65m)8ft 6in (2.6m)8,2311b (3,734kg)5,410 Ib (2,454kg)530mph (854kph)Ix Heinkel He SOilAturbojetrated at2,8651b (I2.75k )static thrust2x30mm MkI08 cannon

Europe wa almost over. The Ar I may havebeen tested as a wind tunnel model, butnever got much further than the early designphase.

Details of the Ar I and other Arado nyingwing projects were secured by US Intelligence and the documentation appear tohave been passed to the US aircraft companyVought, which used them to develop theF7U-l Cutlass jet fighter.

Maximum speedEnduranceCeilingArmament

CrewWingspanWing areaSweepAspect ratioLengthHeightEmpty weightGross weightPowerplant

Armament

Note: Some figures for the Arado design detailed on thesepages are the best available estimates and should not beregarded a definitive.

Arado Ar 1 (E.583)

CrewWingspanSweepWing areaLengthHeightGross weightEmpty weightMaximum speedEngine

Arado E.581-4

AradoAr 1Although the E.555 and E.581 both met withcancellation at the end of 1944, the aerodynamic research had already been made available to the company's design group headedby Professor Walter Blume (1896-1964) whowas working on ideas for an all-weather/nightinterceptor and a ground attack light bomber.His team produced two distinctly differentconcepts for this project. The first was anadvanced tailless jet-powered design designated Ar I and the second was a conventionaltailed alternative with an engine beneatheach wing known as Ar2. This second proposal utilised experience gained from development of the Arado Ar234 Blitz jet bomberand was probably regarded as something of afallback option. The normal 'E' code does notappear to have been assigned to this study.

The taille s Ar I combat aircraft utilisedwhat was effectively a delta wing with a 35°sweep and two vertical stabilisers with rudders. The fuselage extended ahead of thewing to allow the carriage of weapons and aforward installed centimetric radar system.There would also be a pressurised cockpitable to accommodate two crew members.Power for the Ar I would be provided by twoHeinkel He SOIl turbojets or two BMW003Aturbojets located on the underside of thewing. The aircraft would be supported on theground with a tricycle undercarriage. At areview of the Ar I project in March 1945, concerns were expressed about problems ofdrag induced by the wing's surface area andthe engine installation.

A deci ion was then taken to make immediate corrections to the design, most noticeably by an alteration to the profile of thewing's trailing edge. This revised version ofthe Ar I also included changes to the fuselageand a rearrangement of the cockpit layout toallow the carriage of a third crew member. Itis hard to know if the project progressed veryfar beyond these proposals as the war in

The design was virtually a delta shape inappearance, using two vertical tabiliserswith rudders and it would have beenequipped with a retractable tricycle undercarriage. The E.581-4/5 was fairly ugly whenseen side on with the fuselage looking ratherlike a bathtub. However, there is no rea on tosuspect that it wouldn't have performed reasonably well and the estimated maximumspeed was 530mph (854kph). Endurancewould have been fairly limited and its primaryrole would have been as an interceptor. evertheles ,this project did not progress very farand was crapped at the same time as theE.555-1.

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"

Although the twin-jet powered Arado Ar Inever progressed to the hardware stage,it appears to have strongly influenceddesign of the later American Cutlasscarrier-based fighter. Bill Rose Collection

Developed alongside the Arado E555bomber, this small tailless fighteralso met with cancellation in late1944. Bill Ro e Collection

Arado's Flying Wing FighterRunning alongside the Arado E.555 projectwas a study for a high-speed single seat fighterthat would utili e ome of the same aerodynamic properties. The name of this projectwas Arado E.581 and there are known to havebeen at least five separate proposals. Detailsof E.581-1 to E.581-3 remain obscure, althoughthey are thought to have been extremely compact configurations. The slightly larger AradoE.581-4 and very similar E.581-5 were builtaround a single Heinkel HeS 0II turbojethoused in the fuselage below the wing withthe air intake below the nose.

f1u

methods of improving the aircraft's performance remained under study. Dr Lautehoped that the performance of jet engineswould continue to improve and progre ivelyreduce this shortcoming. It is believed thatmodels were wind tunnel tested andalthough E.555-1 was a very advanced concept with considerable promise, it was alsoshowing signs of becoming a very expensiveproject that would become a drain on essential war resources. As a consequ nce, theEntwicklungs-HauptKomission (EHK) orderedthe proj ct's immediate cancellation on 28o cember 1944.


31 ft 2in (9.5m)40°24ft lOin (7.55m)5,9741b (2,71 Okg)9,2151b (4, 180kg)I xHeinkel He S0IIA turbojetrated at 2,8651b (l2.75k )static thrust600mph (965kph)at 20,000ft (6,000m)40,000ft (12,192m)Different configurations including2-7 forward firing 30mm Mk I0cannons, R4M rockets or bombs

I26ft 3in (8m)45° at 0.5 chord23ft 4in (741 m)9,2601b (4,200kg) (estimated)I xHeinkel He SOilAturbojetrated at 2,8651b (l2.75kN)static thrust500mph (800kph) at altitude(estimated)3x 30mm Mk I08 cannons inthe nose

Dr Richard Vogt was one of the great aeronautical designers of the 20th century. He diedat Santa Barbara, California, in 1979, aged 84.

BVAe607 P.217

BV P.212-03

Maximum speed

WingspanSweepLengthEmpty weightGross weightPowerplant

BV P.215.02

CrewWingspan (overall)(main)

SweepLengthHeightWing areaEmpty weightGross weightPowerplant

CeilingArmament

CrewWingspanSweepLengthGross weightPowerplant

Armament

20r36ift 8in (18.8m)47ft 3in (144m)30°38ft lin (11.6m)16ft Sin (5.0m)678. 13ft' (63m')16,3141b (7,400kg)32,3631b (14,679kg)2xHeinkel He 0IIA turbojets,each rated at 2,8651b (12.75kN)static thrust

Maximum speed 560mph (900kph)Ceiling 48,500ft (14,783m)Range 1,400 miles (2,253km)Endurance 5hourArmament 5x30mm Mk I08 cannonsmounted in the nose, although various alternative layoutswere considered. It was also planned to fit two Mk108cannon in aremote·controlled rear·facing turret and theidea of having two upward·facing cannons was considered.Other options were R4M unguided rockets and thepossibility of carrying bombs for use in the ground strike role.

Maximum peed

sidered included ejection seats. By most standards, the P.215-02 would have been heavilyarmed with five forward-facing 30mm cannons, one or two rear-facing 30mm cannonsin a remotely controlled backward-facing turret and the option of two 'Schrage Musik'(Jazz/Slanted Mu ic) upward firing cannonsto be used while passing beneath an enemybomber. The aircraft could also be used as alight bomber with provision to carry twoI, I 021b (500kg) bombs beneath the fuselage.

Like the other Blohm und Voss taillessfighter proposals, the P.215-02 could be easilytransported by road once the wings wereremoved, allowing for use at improvised dispersed sites such as suitable stretches ofautobahn.

The Technische LuftrUstung modified itsrequirements for a future jet-powered nightfighter in late February 1945 which was toodemanding for the P.215-02 and its fellowcompetitors. Subsequently, it was decided togo ahead with development and testingwhich received official approval in March1945. But with only weeks remaining beforethe war ended, no further progress was madewith this interesting series of tailless aircraft.Although these B&V jet fighters had rather anunorthodox appearance, wind tunnel testsindicated that the P.212 and P.215 wouldhave performed well. This appears to havebeen confirmed in recent times by model aircraft constructors who have built and flownscale sized jet-powered replicas.

There was one other advanced Blohm undVoss fighter project under development during the final months of World War 2 with thereference Ae 607 or P.217. This design differed considerably from all those previouslydiscussed. It was a small, single-seat lightweight highly-swept flying wing fighter, powered by a Heinkel He S OllA turbojet.Because of the velY compact nature of thisaircraft, it was necessary to offset the cockpit,placing it alongside the engine in a centralposition. Another unusual feature was thesmall canard control surfaces that wereadded to improve low-speed stability. Fewdetails of this study are available, but it isunderstood that the Ae 607 was shelved infavour of the P.212-03.

After hostilities ceased, Dr Richard Vogtwas recruited by the Americans under Operation 'Paperclip' and taken to the UnitedStates. He worked for the USAF until 1954,later becoming head of the design office atthe Astrophysics Development Corporation.In 1960, Dr Vogt joined Boeing where heworked on VTOL systems and hydrofoils.His final work with the company involvedpost-launch evaluation of the Boeing 747.

minium in non-load-bearing areas of thewings. With wind tunnel testing underway,the P.212-03 was entered for the Luftwaffe'sEmergency Fighter Competition, which hadbeen organised by the Oberkommando derLuftwaffe (OKL - Luftwaffe High Command).Other designs were submitted by Heinkel,Junkers, Messerschmitt and Focke-Wulf,with Focke-Wulf's Ta-183 being selected fordevelopment and production.

However, the P.212-3 was considered sufficiently interesting to remain under consideration as a future Luftwaffe combat aircraft.Meanwhile, another tailless Vogt design thatcarried the reference P.215-02 was underreview for the role of night fighter to meet a1944 specification issued by the TechnischeLuftrUstung (Technical Air ArmamentsOffice). They required a new combat aircraftwith a maximum speed of 559mph (900kph),a minimum endurance of four hours, the ability to carry FuG240 or FuG244 radar and anarmament of four 30mm cannons. Vogtresponded with a broadly similar design tothe tailless P.212, but somewhat larger in sizeto accommodate two side-by-side HeinkelHe SOIl A turbojets, air intercept radar equipment and a pressurised cockpit capable ofaccommodating three crew members.

Construction-wise, the Blohm und VossP.215-02 was built using all the same techniques developed for earlier designs, with themajority of components made from steel,although some non-load bearing parts wouldbe aluminium and control surfaces would befabricated from wood. It was also planned tomake the nose section from shaped woodenpanels, as this component covered the radarunit and needed to be non-metallic. Asidefrom a short section of inner trailing edges,the wing's chord was constant along itslength like all earlier proposals in this series.The sweep was reduced to 30° and thewingtip fin arrangement was almost identicalto the P.212. The overall wingspan includingthe dihedral winglets was 61ft 8in (18.8m),reducing to 47ft 3in (l4.40m) for the mainwing. The main supporting feature of thewing was a centrally-located steel-weldedbox and it was planned to divert warm airfrom the engine compartment into the wingsfor de-icing. A tricycle undercarriage supported the aircraft on the ground, comprisingof a rearward-retracting nose-wheel that wasnormally used on the Heinkel He 219 and twoforward-retracting main wheels.

Several different cockpit layouts were considered, that included a side-by-side arrangement for two crew members a two seattandem arrangement and provision for a rearward facing radar operator. All options con-

I35ft (I 0.66m)35°24ft (7.3m)I xHeinkel He SOIIA turbojetrated at 2,8651b (12.75kN)static thrust559mph (900kph)2x 30mm Mk I08 cannons

I37ft lOin (l1.52m)30°24ft (7.32m)54671b7,5001bI xBMW003A turbojet rated at1,760 Ib (7.8k ) static thrust+500mph (+805kph) approx35-40,000ft (I 0·12,000m) approx2x30mm Mk 108 cannons

BV P.210-01

BV P.209-01


CrewWingspanSweepLengthEmpty weightGross weightPowerplant

Maximum speedArmament

CrewWingspanSweepLengthPowerplant

The Skoda-Kauba V-6 Experimental aircraft is seenin its completed form before undergoingmodification that allowed testing of wing designsfor Blohm & Voss' advanced jet fighters. The fateof this aircraft is unknown. Bill Rose Collection

series of jet fighters and his next proposal wasthe P.212. It had been under developmentsince autumn 1944, with initial plans to beginthe construction of three prototypes in February 1945, with test flight commencing inAugust 1945. The Blohm und Voss P.212-03would be powered by a Heinkel He SOIl turbojet and came to be regarded as the mostrefined version of this tailless series with anestimated maximum speed of almost600mph (965kph) at 20,000ft (6,000m), a service ceiling of 40,000ft (12, 192m) and unspecified but apparently good endurance. Theforward positioned fully pressurised cockpitwould have provided good visibility and theaircraft was to be supported on the ground bya tricycle undercarriage. A wide range ofarmament options were studied for thisdesign which included various numbers offorward firing cannons, R4M rockets orbombs for limited ground attack missions.

The overall wingspan was to be 31 ft 2in(9.5m) although this was shortened slightlyduring a review. It was also decided that the45° sweep would be reduced to 40° and thechord would be altered to allow larger fueltanks and improved structural provision forexternal stores. Although Vogt favoured anall-steel construction, allowances were madefor the P.212-03 to utilise wood and alu-

then became P.211-02. The proposal was for arather crude-looking straight-winged aircraftwith a tail, powered by a BMW turbojet withinthe fuselage. But the B&V designers also produced an altogether superior concept calledthe P.211-01. This had a similar wing shapeand sweep to the P.210-01, but without thebooms and wingtip fins. In overall appearance, the P.211-01 was somewhat similar tothe advanced Messerschmitt P.1IOI jet fighter,which had almost been completed at the endof the war and was secured by US forces.

Although the tailless B&V design was considered to be the best submission for theRLM's Volksjager contest, the HeinkelHe 162A was finally selected for full development. This lightweight fighter not only flewbefore the end of the year but also saw operational service when fuel supplies permitted.Despite losing out, Vogt was encouraged tocontinue with development of the tailless

The most advanced version to emerge from theBlohm & Voss tailless jet aircraft programme wasthe BV215, designed as a night-fighter. It receivedapproval for full development in March 1945.Chris Gibson

o Fl 10

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engine duct and supported the wings. Forpropulsion, a BMW003A turbojet would beused, providing 1,760 Ib (7.8kN) static thrust. Itis difficult to verify the exact wingspan of thisdesign, but the best sources suggest an overall figure of 37ft lOin (11.52m). Sweep alsoappears reduced to 30°. The overall lengthwas about 24ft (7.32m) and take-off weightwould have been approximately 7,500 Ib(3,402kg). There are no details available ofestimated performance, but it seems likelythat a maximum speed in excess of 500mph(805kph) was anticipated, with a ceiling of atleast 35,000ft (I0,000m). The armament wasto be two forward firing 30mm Mkl08 cannons fitted on each side of the cockpit.

While this project was underway, Vogt andAmtmann started working on a more conventional alternative. There is some confusionabout the designation of this design, whichappears to have started out as P.210-02 and

38 Secrel Projects: Flying Wings and Tailless Aircra!1 German World War 2 Flying Wing Deuelopmenl 39

n, I, IU

I31ft (944m)40' (leading edge)19ft IOin (6.04m)8,5761b (3,890kg)636mph (1,023kph)45,000ft (13,716m)I x Heinkel He SOIIA turbojets,rated at 2,8651b (1275kN)static thrust2x30mm MkI08 cannons

I29ft6in (9m)40' (leading edge)191.6ft' (I7.8m')20ft (6 1m)7ft8in (233m)5,4108,6431b637mph (I,027kph) at sea level40,OOOftt (12,192mt) (estimated)I x Heinkel He SOil Aturbojets,rated at 2,8651b (12.75kN)static thrust2x30mm Mk I08 cannons

""""

Heinkel P.I078C

Armament

CrewWingspanSweepWing areaLengthHeightEmpty weightGross weightMaximum speedCeilingPowerplant

Armament

CrewWingspanSweepLengthGross weightMaximum speedCeilingPowerplant

Heinkel P.I078B

a tailless twin-engine concept (P.I079B-I)that used the same gull-wing wing profile asthe P.I078 designs. For stability, this aircraftwould use a single upright tailfin. Gunterchose the same complicated folding tricycle

(lI IU

In 1944, Focke-Wulf attempted to fulfil the RLM'srequirement for a jet bomber capable of reachinga maximum speed of 62 I mph (I ,000kph) andcarrying a 2,240 Ib (I,OOOkg) bomb load over adistance of 621nm (I,OOOkm). This specificationbecame the Project 1000 x 1000 x 1000. Thedrawing shown is for the Model B flying wingproposal, Design Nr 031 0239/10. Bill Rose Collection

The engine's air-inlet was positionedbetween both nacelles, there were no uprightcontrol surfaces and the gull-wing profile wasvirtually identical to that of the P.I 078A. Thethird design for the emergency fighter competition known as the P.l 078C also retainedthis 40° sweep gull wing, but used a shortfuselage section without any upright controlsurfaces. With an appearance more like theBlohm und Voss P.212-03, this single-seatdesign was chosen as Heinkel's preferredentry for the competition. Powered by a single Heinkel He SOIl turbojet fed from a noseintake, the fuselage was constructed mainlyfrom steel with the wings built from wood.This was also where the aircraft's entire fuelsupply was accommodated. A fully retractingtricycle undercarriage was chosen withwheels turning through 90° to lie flat along thefuselage and the proposed armament wastwo 30mm Mkl08 cannons installed belowthe cockpit, each with 100 rounds of ammunition.

The Luftwaffe expressed concerns aboutmany of the aircraft's features such as theunprotected fuel tanks in the wings and theaerodynamic shape of the fuselage. It concluded that this proposal was less satisfactorythan the other leading entries and as a consequence Heinkel abandoned further development work in late February 1945. Gunter'sdepartment was now concentrating ondesigns for a larger twin-engine night fightercalled the P.I 079 which began with a reasonably conventional design using engines in thewing roots, a modest 35° wing leading edgesweep and V-tail. This was soon replaced by

Heinkel Tailless Projects

additional flight control. Down-turned stabil-ising fins and rudders were positioned at thewingtips and the wing's sweep was to be 45°(some sources claim slightly less). The aircraft was supported on the ground by a fullyretracting tricycle undercarriage and thecockpit was fully pressurised with the potential for expansion to accommodate a secondcrew member. Although this Focke-Wulfproject progressed little further than the earlydesign stage, some aspects of the studyappear to have proved influential with US andBritish designers during the post-war years.

Heading Heinkel's design office was SiegfriedGunter (1899-1969) who was unquestionablyone of the company's greatest assets. He hadworked alongside his twin brother Walter ona number of important Heinkel aircraft thatincluded the He 51, He 70 and He Ill. Walterwas killed in a car accident in 1937, butSiegfried continued as a designer with thecompany. Having been involved with theearly development of jet aircraft, SiegfriedGunter and his chief engineer Karl Schwaerzler took direct control of Heinkel's entry forthe Volksjager Competition, which led to thesuccessful He 162A Salamander. The aircraftwas built, undertook its first test flight on 6December 1944, underwent various revisionsto correct serious problems (thanks to theassistance of Dr Alexander Lippisch) andentered production almost immediately, witha small number of He 162A fighters becomingoperational by March 1945.

With the He 162A in production, work atHeinkel's design office in Vienna wasfocussed on the development of moreadvanced versions of this warplane and asuitable proposal for the OKL's EmergencyFighter Competition. This quickly led to threevery unusual concepts. Designated P.I078,the first study in this series (P.I 078A) was themost conventional looking and took the formof a single-seat jet fighter with nose intake,forward cockpit and straightforward tail unit.In many respects, the fuselage was similar tothat of the Messerschmitt P.IIOI jet fighter,but was fitted with rather unusual gull wingswith a 40° leading edge sweep.

The second design (P.1078B) was for acompact single-seat flying wing fighter, powered by a single Heinkel He S OIl turbojet.However, this proposal had a very usual layout with two forward fuselage nacelles. Onewould accommodate the cockpit and theother would house two 30mm Mk I08 cannons and the forward undercarriage wheel.

I or possibly 246f1 (14m)45' (leading edge)592ft' (SSm')19ft (58m)9f1 (2.74m)17,8571b (8, 100kg)2xHeinkel He SOIIA turbojets,each rated at 2,8651b (12.75kN)static thrust659mph (IO,60kph)46,OOOfi (14,OOOm)1,305 miles (2, 100km)Over 2,2041b (I,OOOkg) bomb load.Initially, no defensive weapons.

CrewWingspanSweepWing areaLengthHeightGros weightPowerplant

focke-Wulf fW IOOOxlOOOxlOOO Project B

Maximum speedCeilingRangeArmament

Focke-Wulf Fw 1000 X 1000 X 1000Bomber Project B

In 1944, Focke-Wulf began a series of studiesto fulfil the RLM's requirement for a jetbomber capable of reaching a maximumspeed of 1,000kph (621 mph) and carrying aI,OOOkg (2,204Ib) bomb load over a distanceof I,OOOkm (621 miles). This specificationthen became the name of the project: 1000 x1000 x 1000. Focke-Wulf is known to haveworked on three different proposals. All wereto be powered by two Heinkel Hirth 109-11 Aturbojets and the first two studies were conventional in appearance, rather like the postwar Yakovlev Yak-25 (which might haveutilised some of this design work), while thethird was a tailless flying wing.

There is confusion about whether thesestudies were simply called Project A, Band C,or Project A-I, A-II and B. In addition, there isone source that claims this study was designated 031 0239/10, which may have been thecorrect company project number. On thestrength of what details are available, it is bestto simply refer to the Focke-Wulf flying wingproposal under discussion as Project B. Thedesigner primarily responsible for this workwas Dr Heinz von Halem, who is now remembered for his very exotic Triebflugel (thrustwing) fighter concept produced in late 1944.While developing Project B, he was a sistedby the brilliant aerodynamicist Dr DietrichKuchemann, who later became a senior official at RAE Farnborough, worked on Concorde and was honoured with a CBE.

The aircraft that emerged from this collaboration was the delta-shaped flying wing,with its two engines located in a central position and fed from leading edge air intakes atthe wing roots. It is also possible that deflector plates were proposed as a means of vectoring jet exhaust flow and providing

3113f13in (34.5m) estimated(all sources vary slightly)60fl (18.28m)14f19in (45m)69,400 Ib (3I,480kg)2xBMWl09·018turbojets,each rated at 7,4961b (33.3k )static thrust600mph (965kph) estimated(sources vary)Unknown2,485 miles (4,000km)2x20mm cannons in remote·controlled tail turret and 11,020 Ib(5,000kg) bomb load

IIIIU

"U

CeilingRangeArmament

LengthHeightGross weightPowerplant

During World War 2, BMW produced anumber of little·known proposals for highperformance jet fighters and bombers. Thisdrawing shows the advanced twin-engineStrahlbomber II. Bill Rose Collection

~\ .... ,..,J\....../

BMW Strahlbomber II

CrewWingspan

Maximum speed

crew compartment would be separate. TheStrahlbomber II would be equipped with aremotely controlled gun turret in the tail fittedwith two 20mm MG 151/20 cannons and theaircraft would be capable of carrying an11,0201b (5,000kg) bomb load. The aircraftwould be supported on the ground by a substantial tricycle undercarriage and the designsuggests that BMW may have been aiming forgood high-altitude performance. Relativelylittle is known about these studies, but likemany other advanced German wartime projects, this particular design never left thedrawing board.

/1

, ,' .. ,.,1

BMW is not usually associated with thedesign of combat aircraft, but during WorldWar 2, the company developed two proposals for a Strahlbomber (jet bomber). The firstdesign produced in 1944 was to be poweredby six BMW003A engines, with four of theengines buried in the wings and two locatedin a fairing beneath the cockpit at the front ofthe fuselage. The aircraft would be a sweptwing design with no tailplane, flown by a twoman crew. BMW's initial concept soon gaveway to a more sophisticated, twin-engine flying wing bomber, powered by two side-byside BMWI09-018 turbojets. This advancedaxial flow gas turbine was expected to deliver7,4961b (33.3kN) of static thrust and itremained in development until the end of thewar. BMW engineers placed these jet enginesat the second Strahlbomber's centre of gravity to ensure stability and continued flightshould one engine fail. There were no verticalcontrol surfaces and by using the higher performance 109-018 engines this aircraft wasexpected to provide a significantly bettermaximum speed and range than the firstdesign.

The engines carried by the swept-wingStrahlbomber II would be fed from an intakeat the nose, with the airflow ducted aroundthe cockpit. A crew of three would man thisaircraft, with the bomb aimer accommodated in a ventral bay, and each pressurised

BMW Strahlbomber II


", ,, ,LJu

pleted and test flown at Minden in 1943, theRLM cancelled the contract. They nowinstructed the Horten to proceed with development of their proposed jet powered flyingwing fighter-bomber that would become theHorten Ho IX. At this point, all the initial studies for this aircraft had been completed andconstruction work was starting on the firstprototype Ho IX VI (Versuchs I - Experimental or Version One), which would be anunpowered glider. The Hortens planned toundertake extensive testing with this first aircraft and once the bugs had been ironed outthey would move to construction of the Ho IXV2, which would be powered by twoBMW003 turbojets.

Work on this project progressed at a fairlypedestrian rate until it was brought to theattention of Reichsmarschall HermannGoring who took a personal interest in the

The compact Henschel P.135 designed forthe Emergency Fighter Requirement of 1944.Bill Rose Collection

With a full-scale war taking place andawareness that Northrop was working on flying wing aircraft in the United States, seniorRLM officials agreed that the Horten's projects were of special importance. Subsequently, an entire facility known asSonderkommando (Special Detachment) 9based at Gottingen Airfield was made available to them for the design and constructionof new military aircraft. In 1942, Major WalterHorten took command of the installation andReimar soon joined him. In addition to Sonderkommando 9, the Peschke furniture factory at Minden was placed at their disposal forskilled fabrication work.

The brothers began by designing a propeller driven two-seat tandem trainer calledthe Horten Ho VII. Peschke was requested tobegin construction of a small batch of Ho VIIaircraft, but after the first aircraft was com-

I30ft 2in (92m)25ft 6in (777m)612mph (985kph)46,000Ft (14,020m)9,0381b (5,000kg)I x Heinkel He SOIIA turbojetrated at 2,8651b (12. 75k )static thrust4x30mm Mk I08 cannon

Walter Horten (left) and Reimar Horten (right)who produced designs for some of Germany'smost advanced combat aircraft during the WorldWar 2. Courtesy David Myhra

Having established themselves as constructors of elegant and advanced gliders duringthe 1930s, the Horten Brothers (Reimar andWalter) joined the Luftwaffe in 1936 as pilots.However, they were encouraged to continuedesigning and building aircraft, leading to theextraordinary Parabola that was damagedduring storage in 1938 and subsequentlydestroyed having never flown.

In 1939, Reimar and Walter were offeredjobs with Heinkel and Messerschmitt, but disagreements over the ownership of futurepatents prevented the brothers from accepting. Nevertheless, Walter had many highlevel connections within the Luftwaffe andReimar was married to Air Minister ErnstUdet's secretary which allowed them almostunprecedented scope to continue workingon their own aviation projects. It's also worthmentioning that there was a third Hortenbrother, Wolfram Horten, who played somepart in the development of their early designs.He was killed when his Heinkel He II 1 wasshot down over Dunkirk.

Advanced Horten Projects

Armament

CrewWingspanLengthMaximum speedCeilingGross weightPowerplant

Henschel P.135

ated by Chief Engineer Friedrich Nicolaus andknown as the P.135.

Powered by a Heinkel He SOlI turbojet,the aircraft consisted of a compact fuselagewith a nose inlet for the jet engine and a centrally located cockpit. The aircraft would besupported on the ground with a tricycleundercarriage and the P.135 used a sophisticated compound swept wing with straightedge wingtip sections. This was intended tocounteract turbulence at high speed byspreading the effect of compression along thelength of the wing. This was an interestingdesign, but it could not compete against theFocke-Wulf Ta 183 and the project wasshelved.

I29ft 3in (8.9m)215ft' (l9.97m')26Ft 9in (8.15m)621 mph (I,OOOkph)2x900mm diameter Lorin·Rohrramjets, each providing anestimated 3,440 Ib (153kN) ofthrust at altitude, plus four solidfuel booster rockets used fortake·off, each providing2,2041b (9.8kN) thrust2x30mm Mkl08 cannons

Henschel P.135

Heinkel He P.I080

Gunter's most advanced Heinkel projectsuntil autumn 1945. There are two conflictingstories about what happened to SiegfriedGunter after this period. He is known to havebriefly worked for a Berlin car repair shopowned by his father-in-law and was allegedlykidnapped by the KGB and taken to Russiawhere he was forced to undertake designwork on advanced military aircraft. Alternatively, Gunter is said to have sought a job inthe US aviation industry. He was turned downand subsequently approached the Russianswho made him an immediate offer. According to one unconfirmed source, the Germandesigner then travelled to Russia and undertook much of the initial development for theMiG-15 and MiG-17 jet fighters. It should bementioned that the early design history of theMiG-15 remains somewhat obscure,although the use of German research hasalways been acknowledged. Having spentseveral years in the Soviet Union, Gunterfinally returned to West Germany where hejoined the reformed Heinkel Company andworked on supersonic VTOL projects. Hedied in Berlin in June 1969.

Armament

CrewWingspanWing areaLengthMaximum speedPowerplant

Henschel came into existence during themid-19th Century as a constructor of locomotives and by the mid-1930s, had become amajor manufacturer or armoured fightingvehicles. The company produced huge numbers of Panther and Tiger tanks during WorldWar 2, made possible by the extensive use ofslave labour.

Henschel also operated an aircraft divisionthat developed a small number of combat aircraft and several advanced guided missiles.One particularly interesting HenschelFlugzeugwerke AG proposal for the OKLEmergency Fighter Competition of late 1944was a small tailless single engine design cre-

The second completely tailless version of theHeinkel Hel079 jet fighter designed bySiegfried Gunter. hris Gibson

Although Heinkel He SOIl turbojets were thepreferred choice for propulsion, the option toinstall Junkers Jumo 004B engines was alsoconsidered, although this would havereduced internal space and led to a reductionin offensive armament, resulting in three30mm cannons as opposed to four. A furtherdevelopment of this design was the P.I 079B-2which was broadly similar, but dispensedwith the tail fin. Various cockpit arrangements were considered with the preferredoption to have the second crew member facing rearward.

One of the last projects undertaken byHeinkel's Vienna design bureau was theP.I080 ramjet fighter which utilised a numberof features borrowed from earlier tailless concepts. The P.I080 was to be equipped withtwo large ramjet engines on each side of thefuselage, drawing fuel from tanks carriedbetween both units. To achieve the speedrequired for these engines to become operational, four solid-fuel boosters would launchthe aircraft. Presumably, this would havebeen undertaken with a trolley on a hard runway. The P.I080 was not equipped with aretractable undercarriage and would utilise asingle extendable landing skid. Armamentcomprised two 30mm cannons.

Work on these advanced designs continued until the end of March when Heinkelhastily vacated its facilities in Vienna inresponse to approaching Soviet forces. Muchdocumentation was destroyed and Gunter'steam moved to a safer location. However,they were eventually detained by the US andaccording to one report US Intelligenceencouraged them to continue working on

"I": nI T

243Ft (13.1 m)45' (leading edge)31rt (9.44m)630mph 1,013kph (630mph)+40,000ft (+ 12,192m) (estimated)1,678 miles (2,700km)2x Heinkel He SOIIA turbojets,each rated at 2,8651b (l2.75kN)static thrust, or 2xJunkers Jumo004B turbojets (providing reducedperformance)4x30mm MkI08 cannons(3 xMk I08 cannons in theJumo·powered version)

243Ft (131m)45' (leading edge)31Ft (9.44m)630mph (1,013kph)+40,000ft (+ 12,192m) (estimated)2x Heinkel He SOIIA turbojets,each rated at 2,8651b (12.75kN)tatic thrust

1,678 miles (2,700km)4x30mm Mk I08 cannons

\

Heinkel He P.I079B-I

undercarriage arrangement which minimi ed the amount of internal space requiredwhen retracted. Armament was to be four30mm cannons in the nose and the aircraftwould be equipped with centimetric radar.

Heinkel He P.I079B-2

CrewWingspanSweepLengthMaximum speedCeilingRangePowerplant

Armament

RangeArmament

CrewWingspanSweepLengthMaximum speedCeilingPowerplant


project and provided them with his full support. It was obviously encouraging to havebacking from the head of the Luftwaffe whentrying to obtain prioritised components likejet engines, but it also put the Hortens underconsiderable pressure with Goring settingschedules for the rapid introduction of thisnew fighter aircraft.

The Ho IX VI was a flying wing in everyrespect with no vertical stabilisers or ontrolsurfaces, although it is said that Walter Hortenwas strongly in favour of including a singleupright fin on the aircraft. Various materialswere used in the Ho IX's construction, but themain parts of the airframe were a c ntralwelded tubular steel framework with thewings being mostly fabricated from wood.The one-man cockpit was located just behindthe central leading edge and the gliderutilised a tricycle undercarriage. Thretractable nose-wheel was salvaged from acrashed Heinkel He 177 bomber, the twomain wheel were fixed in position and thestruts were enclosed in fairings. This wasapparently considered necessary to assistwith stability because there was no propulsion. Unusual for this time was a brakingparachute fitted in the tail that would be

Opposite page:

Top len: The constructional detail of the HortenParabola's airframe during assembly in t 938.Bill Rose Collection

Top right: Drawing of the Horten Parabola that wasbuilt as a glider but never flown. S Army

Centre len: The Horten Parabola was found to havesuffered damage following storage and apparentlyrepair was not an option. After the war, knowledgeof this glider led US Intelligence to suggest that theHortens had been secretly involved in thedevelopment of flying disc-shaped aircraft,although there was no truth to the idea.Courtesy David Myhra

Centre right: The Horten Parabola glider wasdeliberately set on fire after it was determined thatthe aircraft had been damaged beyond practicalrepair. Courtesy David Myhra

Boltom len: The prototype Ho IX VI flying wingglider being moved by a ground crew inpreparation for a test flight at Oranienburg Airfieldduring mid-1944. Courtesy David Myhra

Boltom right: The sleek Horten Ho IX VI atOranienburg Airfield. Courtesy David Myhra

This page:

Horten Ho IX VI being towed by a small truckacross a snow-covered airfield during 1944.Courtesy David Myhra

The badly damaged centre section of the Ho IX VI,prior to being scrapped. US Army

deployed on landing to slow the aircraft.The Ho IX VI was first flown by test pilot

Heinz Scheidhauer at Gottingen Airfield on IMarch 1944. Following several successfulflights, VI was transferred to Oranienburg Airfield near Berlin for testing by members of theLuftwaffe. When these trials concluded, VIwas tran ported to Brandis. It remained thereuntil 1945 when members of the American9th Armored Division discovered the gliderand eventually destroyed it.

Meanwhile, the second prototype hadbeen assembled in a large garage at Gottingen Airfield, although the planned use ofBMW turbojets was in doubt due to ongoingengine reliability issues and uncertain delivery dates. The only option was to modify thefuselage to take a pair of slightly largerJunkers Jumo 004 jet engines. With changesmade to the engine bays, steel protectorplates were fitted to shield the central trailingedge from hot exhaust from the engines.

By the time both 1,980 Ib C8.8kN) staticthrust jet engines were installed in the Ho IXV2, it was late 1944 and the project wasbehind schedule. This econd prototype wascloser to a production aircraft, although it car-

ried no armament. V2 was fitted with a fullyretractable undercarriage comprising of anose-wheel salvaged from a Heinkel He 177and main wheels from a MesserschmittBf 109.

The first test flight wa undertak non 2 February 1945 at Oranienburg by Leutnant ErwinZiller, an experienced test pilot who hadalready gained some useful experience flyingan Me 262 jet fighter at the Rechlin test centre.The initial flight of the new Harten aircraft wasconsid r d successful, but at the end of thesecond trial on the following day, Ziller raninto problems deploying the parachute tooearly and it resulted in damage to the undercarriage. Thi was repaired, but it meant thattesting was delayed until 18 February 1945.

nfortunately, things went disastrously wrongon this occasion. Ziller suffered a turbojet failure and attempted to land on one engine. Helost control of the aircraft and wa killed in thecrash. The exact cause of the accident wasnever discovered and the investigation thatfollowed could not rule out sabotage.

evertheless, these brief trials were judgedso successful that Reichsmarschall HermannGoring ordered the aircraft into immediate


Right: The largely completed centre section of theHorten Ho IX V3. US Army

Below left: Nearly fully-assembled, the HortenHo IX V3, soon after discovery by members of theUS 3rdArmyVII Corps on 14 April 1945. US Army

Opposite, top: The Horten Ho IX V2 jet-poweredprototype under construction at Gottingen Airfield.Bill Rose Collection/David Myhra Collection

Below right: The Horten Ho IX V6 was alsodiscovered by members of the US 3rd Army VIICorps on 14 April 1945 at the Gotha works,Friedrichsroda. US Army

Bottom right: The Horten Ho IX V3 at theSmithsonian Institution's Garber RestorationFacility in 2000. Courtesy Michael Katzmann

Bottom left: The engines already installed into theHo IX V6 airframe which was at an advanced stageof assembly at the Gotha works by the end ofWorld War 2. US Army

I55ft (I6.78m)28' (leading edge)576.9ft' (53.59m')24ft 6in (7.47m)9ft 2in (2.81 m)576.9ft'II, 1751b (5,067kg)18,7401b (8,500kg)2xJunkers Jumo 0048 turbojets,each rated at 1,980 Ib (8.8kN)static thrust590mph (946kph) at sea level and607mph (976kph) at high altitude4,330fVmin (I,319m/min)52,500ft (I6,000m)932 miles (I ,500km). This couldbe doubled with two 275 Imp gal(I ,350 litre) external drop tanks2or 4x30mm Mkl08 cannons andprovision for 2x2,2041b (I,OOOkg)SCIOOO bombs

Initial climb rateCeilingRange

Maximum speed

Armament

CrewWingspanSweepWing areaLengthHeightWing areaEmpty weightGross weightPowerplant

Horten Ho IX V3/Gotha Go 229A

Unfortunately at the time of writing this interesting aircraft remains in rather a poor stateand it may be some time before this happens.

After the Americans removed V3 fromGotha Waggonfabrik A.G, it is understoodthat a team of engineers were instructed todestroy the remaining uncompleted prototypes before Soviet forces arrived.

Controversy surrounds the supposedstealth capabilities of the Go 229A flying wingand whether it was intended to have a lowradar signature from the outset. The smoothboomerang shape and predominantlywooden construction were a good combination for this. It is also worth noting that 17mmthick sheets of plywood used for the skin contained a middle layer of resin-bonded sawdust and charcoal which worked quite wellas a radar absorbing material (RAM).

The Germans had certainly made progresswith radar countermeasures during WorldWar 2 and managed to effectively maskU-Boat periscopes with the use of a RAMcoating. It is also claimed that during a conversation in 1950, Reimar Horten remarkedthat the largely wooden construction of theGo 229A would have made the aircraft hard todetect by radar. While it remains conceivablethat this aircraft was intended to have astealth capability, it seems more likely thatthis feature arose accidentally from the use oflow-cost materials. No documentation thatrefers to the development or testing of RAMfor this aircraft has been located. Nevertheless, the possibility can't be entirely ruled outand evidence could surface in the future.

By spring 1945, production was underway atFriedrichsroda with the first prototype Go 229AV3 (sometimes also called the Ho IX V3) at anadvanced stage of assembly. Several variantsof the Go 229 were also being assembled andthese were the V4, V5, V6 and V7. In addition,components were being readied for production of the first 20 Go 229A fighter-bombers.The Go 229A V3 was almost ready to beginflight-testing when US forces secured theFriedrichsroda plant in April 1945. The two-seatV6 was about half finished and work wasunderway on the other pre-production aircraft.V3 was then shipped to the RAE at Famborough, Engl~nd, for initial evaluation and fromthere taken to the United States where therewere plans to make it airworthy. But this neverhappened and the aircraft was finally passedfrom the USAF to the National Air and SpaceMuseum which intended to fully restore it.

~~-================~~~o0 II J II 0 0

" f"\: l (1 ::\) I I \.)

I IUHarten Ho IX V3, renamed

as the Gotha G0229A.Bill Rose Collection

production as a new fighter-bomber. Planshad already been drawn up for Gotha Waggonfabrik A.G to begin assembly of severalexperimental prototypes and a further batchof 20 pre-production aircraft at the Friedrichsroda factory. This aircraft would be calledthe Gotha Go 229A and the company's engineers were officially requested to make anumber of general upgrades to the designand minor modifications that would assistwith manufacture. These included cockpitchanges and the installation of a rudimentaryejector seat, alterations to the undercarriage,some aerodynamic modifications to theengine intakes and structural improvementswithin the engine bays. It was decided toinstall four 30mm Mk108 cannons just outboard of the engines and provide hardpointsbeneath the fuselage for either two bombs ortwo drop tanks.


A study of the Horten Ho IX by Gotha's design teamled to an alternative aircraft with a number ofobvious improvements. While lacking the eleganceof the Horten flying wing, the P60A proposal made asufficient impression on the RLM to secure approvalfor further development. Bill Rose ollection

", ,IIU

I45Ft Ilin (14m)Initially 60° at the no eand 43°to the wingtips. (Leading edge)376.7ft' (35m')35.5Ib/ft' (173.3kg/m')23ft in (7.2Jm)7ft 6in (2.2 m)13,3931b (6,075kg)I x BMW003A turbojet rated at1,760 Ib (7.8k ) static thru t, orpreferably I x Heinkel HeS OIIAturbojet, rated at 2,8651b(1274kN) slatic thrust. (Earlyprototype: I x 240hp (I 79kW)Argus As IOC V8pislon engine inpu her configuration)684mph (J,IOOkph) - He SOIIA50,000ft (15,250m) - He SOJ IA1,243 miles (2,000km) - He SOIIAI x30mm MkI0 cannon and2x 20mm MG 151 cannons

r:u

The Hortens were working on a more advancedsuccessor to the Gotha G0229A which wasdesignated as the Ho X (seen here). It wasexpected to enter service during t946 as the newVolksjager (People's fighter). Bill Ro e olleclion

peller for powered trials. This would be followed by a more refined second version,probably equipped with a BMW003A turbojet.

It is not clear what stage of developmentthis project reached by the nd of the war, butLuftwaffe personnel destroyed the Ho Xbefore Allied forces arrived. early all documentation for the Ho X was burnt or simplydisappeared and the Horten Brothersremained less than forthcoming about thisproject after hostilities ceased.

Horten Ho X Volksjager

CrewWing panSweep

Wing areaWing loadingLengthHeightGross weightPowerplant


the pilot in a seated position. The design hadtwo intakes for the turbojet just behind thecockpit on each side of the fuselage. It utiliseda tricycle undercarriage and a productionfighter would have been armed with threeforward firing cannons.

A second, more advanced design with anarrowhead appearance was also called theHo X. It had a 60° leading edge weep andwa powered by a single turbojet in the rearof the body with the inlet just above andbehind the cockpit canopy. Some illu trations indicate an engine nacelle beneath thewing. No vertical control surfaces appear tohave been envisaged and the aircraft wouldbe supported on the ground by a tricycleundercarriage. The pilot would fly this aircraftin a prone position. Almo t nothing is knownabout this design and may have been moreclosely related to the Ho XIII which is discussed shortly. During autumn 1944, severalmall models of HoX designs were built and

test flown. These are said to have hadwingspans of about 9ft lOin (3m). Nothing iscurrently known about these trials, but thecon truction ofa full ized prototype followedat Gottingen Airfield. The Ho X aircraft wasassembled using the same materials andmethod as the Ho IX with a welded tubularsteel central framework and wings madefrom wooden components covered with plywood panels. The aircraft may have beeneither of previously mentioned de igns andwas intended to be flown as a glider first thenfitted with a 240hp (179kW) Argus AsIOeinverted V8 piston engine and a pusher pro-

This aircraft was largely based on theP.60B, but featured a tandem cockpit withconventional upright seating and anextended nose section containing air intercept radar equipment and a 'Morgenstern'(Morningstar) antenna. A variant of thisdesign was considered which would accommodate three crew members and anotherchange was the provision of vertical stabilisers and rudders. It is believed that construction of a prototype P.60C continued until quitelate in the war, but the aircraft was finallydestroyed. Apparently, very little documentation for this project survived.

The Hortens arned a reputation for beingdifficult to get along with and it app ars theywere not entirely happy about anyone elsetrying to improve on their work. However, theRLM recognised the superior features of theP.60 series and 0 did the American scientistswho studied the project after the war. Theyconcluded that although the P.60 showedgreater induced drag resulting in a slight lossof climbing rate and ceiling when comparedto the Go 229, the P.60 was a more stabledesign with better directional control.Although the RLM had been impressed withthe P.60, further developments of the GothaGo 299 were plann d which included a radarequipped night-fighter known as the Go 229B.

Following completion of the Go 229 prototypes at Friedrichsroda, a brief period ofnight-testing was anticipated before the firstbatch of production aircraft were transportedto Brandis for operational deployment asreplacements for the Messerschmitt Me 163Brocket interceptors.

The limited trials that had taken place withthe powered and unpowered Horten Ho IXaircraft indicated that it was faster than theMe 262 jet fighter, but less manoeuvrable thanthe Me 163B rocket-powered interceptor.Nevertheless, it was still more than capable ofattacking the anticipated high-altitude USAAFB-29 bombers.

Horten People's FighterBefore manufacture of the Go 229 commenced, the Hortens were already workingon an improved successor to this aircraft designated as the Ho X which was expected toenter service in 1946 as the new Volksjager(P ople's fighter). There is some confusionabout this design because the designationHo X appears to have been applied to severaldifferent projects. This was apparently donefor security and disinformation purposes.However, the intended successor to theGo 229 was a compact one-man flying wingaircraft with a central fuselage section and acompletely faired-in co kpit accommodating

2,later344Ft 4in (13.5m)45° (leading edge)588.7 Ft' (54.7m')35Ft 9in (11.5m)II Ft 6in (3.5m)23,082 miles (J0,470kg)596mph (959kph)43,600Ft (13,300m)1,367 miles (2,200km)3.55 hI's2x Heinkel He SOil each rated at2,8651b (J 2.74kN) tatic thrust2x Mk I08 30mm cannons firingforward, plus 2x30mm Mkl08cannon in centre section firingupward at an oblique angle.Exten ive radar and electronicequipment for the night fighter role.

244ft 4in (1305m)45° (leading edge)588.78Ft' (54.7m')32Ft 6in (9.9m)II Ft 6in (305m)21 ,9431b (9,953kg)604mph (973kph)40,500Ft (J 2,400m)1,740 miles (2,800km)2x Heinkel He SOIl each rated at2,8651b (12.74k ') tatic thrust4x 30mm MKI0 cannonsI x Rb50/1 camera andI x Rb30/l8 camera

240Ft Iin (J 2.2m)45° (leading edge)504ft' (46.8m')2 Ft II in ( .82m)II Ft 6in (3.5m)16,4241b (7,450kg)569mph (915kph)41,000Ft (J2,500m)994 mile (J ,600km)2x BMW003A turbojets,each rated at 1,760 Ib (7.8kN)static thru t4x 30mm MKI08 cannon2x Rb50/18 cameras

ArmamentReconnaissance role

CrewWingspanSweepWing areaLengthHeightGross weightMaximum speedCeilingRangePowerplant

CrewWingspanSweepWing areaLengthHeightGros weightMaximum speedCeilingRangeEndurancePowerplant

Gotha Go P.60B

ArmamentReconnais ance role

CrewWingspanSweepWing areaLengthHeightGro sweightMaximum peedCeilingRangePowerplant

Armament

Gotha Go P.60A

Gotha Go P.60C

its cancellation and a switch to developmentof a third version intended for use as a nightfighter called the P.60C.

tude Fighter) and assigned the project designation P.60NR. The pressurised cockpit wasflush with the aircraft's wing and took the formof a glazed forward section with accommodation for two crew members, although theywould be lying side-by-side in prone positions.

While this would allow the crew to standhigher g forces, it also raised serious questions about their ability to escape from the aircraft in an emergency. To address thiquestion, the idea of mounting both enginesbelow the wing was studied, but found toreduce the roll rate. The problem of abandoning the P.60A in an emergency was neverresolved, although there were suggestions todevelop some kind of crew ejection mechanism. The P.60A would be upported on a tricycle undercarriage with a lengthy strut forthe nose-wheel which turned through 90°during retraction to minimise the use of internal space when stowed. Control surfaces onthe trailing edge of the wing were upplemented by drag rudder at the wingtips. Tocounteract tall during landings, the wing'sleading edge was fitted with hydraulicallycontrolled split flaps.

Probable armament for the P.60A wouldhave been four 30mm Mk I 08 cannons. Thisaircraft could have been fitted with a camerapack for high altitude reconnaissance missions. A further development was the slightlybigger P.60B that would benefit from a simplified internal structure, a modest rearrangement of the cockpit and an engineupgrade to Heinkel He S OIl turbojets.Assembly of the first prototype P.60B wasunderway during February 1945, although achange of requirements within the RLM led to

~~~:E:r:~~n 0 f'" II'J IIU f1 \.)

"

Gotha ProjectsOnce Gotha Waggonfabrik A.G had beenselected to manufacture the Horten-designedfighter-bomber, a team of company engineers headed by Dr Hlinerjager set aboutundertaking various improvements to the aircraft that would make it more suitable forLuftwaffe service and a easy and cost effective to produce as possible. Their initialassessment of the Horten design led Gotha'steam to begin work on an alternative conceptfor a flying wing aircraft that utilised many ofthe same constructional features, but wasgenerally more advanced than the Go 229Aand could be upgraded with less difficulty.Major differences included the use of externally mounted engines in nacelles and anentirely different cockpit layout. The initialproposal for this de ign was submitted to theRLM in early 1945, which were sufficientlyimpressed to commission further research.

This proj ct now rec ived the referen eGotha P.60A. It would be built from a combination of steel and wood with propulsion provided by a pair of turbojet mounted aboveand below the centre of the wing. The initialchoice was BMW003A turbojets, althoughthese could easily be replaced with moreadvanced versions, or engines manufactur dby Junkers or Heinkel. Becaus the turbojetswere carried outside the aircraft's body, maintenance or replacement of these units wouldhave been much simpler than found with theHorten fighter. A further development of theP.60A was to install an additional WalterHWK509B rocket engine and increase the aircraft's ceiling and climb rate. This proposalwas referred to as the Hohenjager (High Alti-


The extensively-revised layout forthe Horten Ho XVlIIA long-range jetbomber. Bill Rose Collection

o decisions were made at that time,although several days later the Hortens wereinvited to Reichsmarshall Goring's office andadvised by him that their design had beenselected. They were told that Junkers wouldbe responsible for building the new AmerikaBomber with a i tance from Messerschmitt.A meeting between the Hortens and engineer from Junkers and Messerschmitt wasarranged and when it took place there wasconsiderable disagreement about the designwith Junkers engineers recommending amajor revision of the Horten's Ho XVIlla proposal. Junkers wanted to add a large centralfin and rudder to the bomber and the Hortensreluctantly agreed to this, plu the use of sixJumo 004B turbojets located beneath thewing in two nacelles and a fully retractable tricycle undercarriage.

Heinkel He SOil turbojets were the preferredmethod of propulsion, although it wasaccepted that Jumo 004B turbojets might beadequate. The possibility of using turbopropsin a similar configuration to the orthrop B-35was also briefly con idered and rejected.Engine intakes were located in the inner leading edge and the idea of using a rocketassisted launch trolley and landing skid wasdiscussed as a weight saving measure. Onefurther idea considered by the Hortens wasin-flight refuelling, although it remained relatively new and unexplor d technology andmet with final rejection. On 25 February 1945,the Hortens were invited to present thedetails of their Amerika Bomber proposals atan RLM review in Berlin that was attended byrepresentatives of the five other aircraft companies who were participants in the contest.

Horten Amerika BomberAnother major design project to be undertaken by the Horten brothers was a longrange flying wing bomber. In 1944, the RLMissued a requirement to the leading Germanaircraft contractors for a long-range bomberthat was capable of undertaking attacks onAmerica' eastern seaboard. The Luftwaffewanted a high altitude aircraft capable ofdelivering four tons of bombs (or possibly onespecial weapon) to a chosen target and completing the round trip of about 7,000 miles(11 ,265krn) without refuelling.

Five submissions were received by theRLM, although every company expressedconcerns that the requirement was toodemanding with prevailing technology. As aconsequence, these designs were rejectedand the RLM requested fresh proposals. TheHortens had not been approached to participate in the first competition but were awarethat it had not been a success, so theydecided to start design work on a flying wingaircraft which they called the Ho XVIIIAmerika Bomber. By I January 1945, thebrothers had produced about 10 initial concepts, mainly differing in the number ofengines used and their positioning.

The design preferred by the Hortens was alarge, smoothly-contoured flying wing withfour or six buried engines. This resembled across between the Ho IX fighter and the modern B-2A bomber in appearance. Advanced

Original artwork for the Horten Ho XVIII strategicjet bomber, looking decidedly advanced for itstime. Bill Rose Collection

Lippisch. The supersonic Ho XlIIb wouldhave been powered by a mixed propulsionsystem. This could have been either aBMW003R combined turbojet linked to aBMW 109-718 rocket engine or a Heinkel He S011 turbojet and a supplementary Walterrocket engin . The fighter was expected tohave a high rate of climb and be capable ofmaintaining upersonic level flight during acombat mis ion. The Hortens believed that amaximum speed of Mach 1.4 was realistic,although this may have been rather optimistic. Supported on the ground by aretractable tricycle undercarriage, theHoXlllb would have been armed with two30mm MG 213 cannons. The HoXlIIb represented the cutting edge of aircraft design in1945. Proposals to have this aircraft in serviceby 1946 seem like wishful thinking, but theHoXIII project shows how much progresshad been made in a few short years andexplains why the Allies were so eager tosecure details of these programmes.

I39ft 4in (12m)60° (leading edge)39ft 4in (12m)UnknownI x BMW003R combined turbojet,producing 2,2051b (9.8k I) taticthrust and aBMW109-7181iquidfuel rocket engine providing 21b(3.92k ) thru t1,118mph (1,800kph)50,OOOft (l5,240m) approxUnknown2x30mm MG213 cannons

I39ft 4in (12m)387.5ft' (36m')60° (leading edge)32ft 9in (10m)

nknown4.0550lb (250kg)727lb (330kg) approx

oneIIImph (l80kph)27mph (44kph)27mph (44kph)UnknownN/AWater

one

1aximum speedCeilingRangeArmament

CrewWingspanweep

LengthHeightPowerplant

CrewWing panWing areaweep

LengthHeightAspect ratioEmpty weightTake-off weightPowerplantMaximum speedtall speed

Landing peedCeilingRangeBallastArmament

Horten XIIIb (Ho X) Supersonic Fighter

Horten Ho XIIIa Glider

about the same size as the HoXllla with thesame 60° wing sweep. But unlike the glider,there would have been a substantial upright fincontaining the cockpit in very similar fashion tothe proposed supersonic Lippisch P.13.

This similarity has often been remarked onalthough Reimar Horten denied any knowledge of Lippisch's work during his time inpost-war London. However, this se ms highlyunlik Iy and there was almost certainlywartime contact between the Hortens and

Bouom: The Ho Xlllb supersonic fighter was theHorten brothers' most advanced concept thatwould have used a mixture of rocket and jetpropulsion. This is believed to be the generalappearance of the design. Bill Rose Collection

Left: Developed from small models, the HortenHo Xllla was a single-seat glider built with a sweepof 60° to test various ideas about future supersonicnight. Trials began in 1944 and the next (eventual)step would have been construction of a Ho Xlllbprototype with supersonic performance.Bill Rose olleclion

4"" .- "

took place at Gollingen Airfield on 27 November 1944 and a further 19 nights were conducted at Hornberg by Hermann Strebel whoreported that the glider handled wellalthough he complained about poor roll control, limited forward visibility and landingproblems cau ed by the extended skid.

Nevertheles ,the Hortens were contemplating the construction of a more advanced prototype that would be powered by an ArgusAslO piston engine in a pusher configuration.But this never came about and at the end of thewar a group of Ru sian soldiers who had justbeen liberated from a prison camp discoveredHoXllla and destroyed it. Furthermore, all theplans and research material for this projectvanished without a trace. It now appears thatthe HoXlllb was the anticipated final development of this programme and it was expected tohave supersonic performance under certainconditions. Looking very much like an advanceLippisch design, this fighter would have been

Horten Supersonic FighterBy 1943, the Hortens were discussing the possibility of supersonic night. While thisremained uncharted territory, they decided toexperiment with a highly swept glider thatwould provide an understanding of slowspeed handling with a highly swept configuration that might by capable of reaching orexceeding Mach 1.

The glider was designated HoXllla andconstruction is believed to have begun inearly 1944. The aircraft u ed wings from theHo III attached to a new central section whichprovid d a span of39ft 4in (12m) and asweepof 60°. The design was very clean with fewprotrusions apart from a dorsal spoiler andthere were no vertical control surfaces. Thepilot was housed in a gondola arrangement,mounted below the centre section, withaccess via a tail cone cover. In an emergency,the pilot would jettison this cover and slideout the back of the unit. The first test night

50 Secret Projects: Flying Wings and Tailless Aircraft German World War 2 Flying Wing Development 5t

carried a 118 Imp Gallon (540 litre) fuel tankand the main 225 Imp Gallon (I ,025 litre) fueltank was positioned at the centre of the aircraft between the cockpit and engine. Thepressurised cockpit was extensivelyarmoured and an ejector seat was fitted.

In February 1945, proposals for the EF.128were submitted to the Emergency FighterCompetition. The outcome is not entirelyclear as Junkers continued to work on thisdesign, producing an engineering mock-upcomplete with a Heinkel He SOlI engine andundertaking wind tunnel testing with scalemodels. Plans were also drawn up for astretched version of the fighter able to carry asecond crew member with a radar systemand greater fuel load. It is unclear how far thisproject had progressed by the end of the war,but relatively little hardware or documentation survived.

Another very interesting Hertel flying wingproject came about during the final months ofthe war while he was heavily involved indevelopment of the Horten Amerika bomber.Carrying double the Horten aircraft's bombload, this larger aircraft was designed to havetrue intercontinental range, allowing strikesdeep into America and Russia. The design reference is uncertain, but Hertel later calledthis study the Very Long Range Bomber(VLRB) project and he anticipated a crew ofeight to ten. Hertel also believed that this largeflying wing would make a good peacetimetransport and passenger aircraft.

The fuselage was fully integrated with thewing and there was a rather ugly nose intakefor the engines positioned directly below thecockpit. Hertel planned to use eight HeinkelHe S 109011 or eight Jumo 109012 enginesturbojets buried in the fuselage. The aircraft

The Junkers EF.128, proposed for theEmergency Fighter Competition of February1945. This project proceeded very quicklyfrom small models, which were wind tunneltested, to a complete engineering mock-up.Chris Gibson

.'....L .J

Much of the initial aerodynamic work for thisproject was undertaken by DFS whichresulted in the aircraft sometimes beingreferred to as the DFS 130.

Construction-wise, the EF.130 would befabricated from low-cost materials with steelcomponents in critical or load bearing areasand wooden sections wherever possible. Acrew of three would be housed in a pressurised glazed cockpit that protruded forward from the leading edge and the aircraftwould be supported by a tricycle undercarriage. Two vertical stabilisers with rudderswere envisaged. The design was in the samegeneral class as Arado's Ar E.555 and the tailless Messerschmitt P.II 08. Wind tunnel models were constructed and tested, but theaircraft failed to win acceptance with theRLM.

At the same time, Dr Hertel's office wasundertaking a parallel study for a smaller flying wing fighter which received the referenceEF.128. The design was for a compact singleseat, single-engine jet fighter armed with two30mm Mk I 08 cannons, each carrying 100rounds and there was the option of fitting twoadditional cannons. The fuselage would beconstructed from welded steel and manyparts of the wings would be made fromwood.

Each wing carried a vertical stabiliser witha rudder and the aircraft would be supportedon the ground by a retractable tricycle undercarriage. Junkers engineers hoped to use aHeinkel He S OIIA turbojet rated at 2,8651b(12.74kN) static thrust for propulsion,although it is likely that the option of fitting aJumo 004 engine was considered. Air intakesfor the turbojet were located on each side ofthe fuselage beneath the wings. Each wing

I (2 seats for aproposedall-weather variant)29ft 2in (89m)45' (leading edge)I89.4ft' (17.6m')23ft (7.05m)8ft 8in (265m)4ft 2in (127m)231.42ft' (21.5m')5,7471b (2,607kg)8,9881b (4,077kg)47lb/ft' (231 kg/m')2,7551b (1,250kg)I x Heinkel He SOIIA turbojetrated at 2,8651b (1274kN)static thru t562mph (905kph) at sea level,615mph (990kph) at altitude45,000ft (13,716m)2x30mm Mk I08 cannons

378ft 9in (24m)UnknownI,291ft' (120m')36ft (11m)Unknown83,790 Ib (38,000kg)615mph (990kph)40,000ft (12, 192m)4,350 miles (7,000km)4x BMW003A turbojets, eachrated at 1,760 Ib (7.8k ) staticthrust or 4x Heinkel He SOil Aturbojets, each rated at 2,8651b(12.74k ) static thrust8,8201b (4,000kg) bomb load,defensive rearward firing 30mmcannons possibly two forward30mm cannon

In 1943, a team of designers working under DrHeinrich Hertel (I902-1982) began to consider possible ways of meeting future RLMrequirements for a new long-range high performance bomber. Their favoured choicewas a flying wing aircraft. The project wasdesignated EF.130 and as the conceptsteadily evolved, a decision was made topower the aircraft with four BMW003 orpreferable Heinkel He SOIl turbojets whichwould be mounted side-by-side towards thecentre-rear of the flying wing's upper side.

Maximum speed

WingspanSweepWing areaLengthHeightFuselage widthFuselage areaEmpty weightGross weightMax wing loadingFuel weightPowerplant

Junkers EF.130

Junkers Ju EFl28

CeilingArmament

Crew

Junkers Flying Wing Projects

CrewWingspanSweepWing areaLengthHeightGross weightMaximum speedCeilingRangePowerplant

Armament

3137ft 9in (42m)62ft 4in (19m)35' (leading edge)97,0001b (44,000kg)4x Heinkel He SOil each rated at2,8651b (1274kN) of static thru t530mph (852kph)Unknown6,835 miles (II ,000km)27 hoursForward and rearward firingdefensive 30mm Mk I08 cannons.8,820 Ib (4,000kg)

498ft 6in (30m)1,780ft' (165.3m')UnknownUnknown73,000 Ib (33,112kg)6,000 US gal6xJunkers Jumo 004B turbojets,each rated at 1,980 Ib (8.8kN)static thrust560mph (900kph)52,500ft (l6,000m)5,593 miles (9,000km)Forward and rearward firingdefensive 30mm Mk I08 cannons.8,8201b (4,000kg)

Horten XVIIIb Bomber

Maximum speedCeilingRangeEnduranceArmament

Bomb load

The partly completed IA38 transport aircraft,designed by Reimar Horten in Argentina during the1950s. The stow pace of construction meant that itwas outclassed by the time it finally flew and metwith cancellation in 1962. Peter Nash

Bomb load

Derwent turbojet with a dorsal intake, the aircraft utilised mid-wing stabilising fins withrudders and a fully retractable undercarriage.The armament would probably have beentwo or four cannons and although performance estimates are unknown, it would havebeen in the class of other contemporary single-engine jet fighters. Although this conceptwas never built, Reimar Horten work d onmany other aircraft designs.

One project that began in 1951 and finallyflew in 1960 was the IAe.38 cargo aircraft. Thiswas a four-engine flying wing design with aspan of 105ft (32m) that flew on four occasions. It was an interesting aircraft thatreflected wartime developments, but finallymet with cancellation in 1962.

CrewWingspanLengthSweepGross weightPowerplant

Horten Ho XVIIIa Early Specification


CrewWingspanWing areaSweepLengthGross weightFuel capacity (max)Powerplant

)

II IIIt IIU 11 \"J

"

ing! Exactly how the aircraft would have performed is debatable, especially as gas turbinetechnology was still at an early stage. Enginereliability was poor and turbojets like theJunkers Jumo 004 were wom out after 25hours of use. Even if the war had lasted longenough for the Luftwaffe to field a few intercontinental jet bombers capable of reachingAmerica or Soviet industrial areas beyond theUrals, it would have made little difference tothe outcome of events.

Following the defeat of Nazi Germany,Reimar and Walter Horten briefly worked forthe British. Reimar then travelled to Argentinawhere he undertook a number of officiallysponsored aviation projects, while Walterremained in West Germany. Having assembled a small team of engineers at the InstitutoAerotecnico at 6rdoba (later the Fabrica Militar de Aviones - FMA), Reimar Horten produced an initial design for a single-seat jetfighter, which was classified as top-secret.

These studies began with a flying wing concept, heavily based on the Horten Ho IX andHorten Ho X. Powered by a single Rolls-Royce

Mter his arrival in Argentina, Reimar Horten beganwork on a flying wing jet fighter for the government.Powered by a single Derwent turbojet, this aircraftwas developed from wartime research and probablyrepresents the ultimate configuration of this series.Nevertheless, it never progressed beyond thepreliminary concept phase. Bill Rose Collection

c

Although initially agreeing to these proposals, Reimar Horten remained unhappy aboutthe modifications and set about making further alterations that resulted in a new aircraftcalled the Ho XVII lb.

His revisions were accepted and it wasnow agreed that four Heinkel He SOIl turbojets would power the aircraft and thesewould be located in underwing podsattached to struts containing the landing gear.It is clear that there was considerable pressure being exerted on everyone involved withthis project. The RLM wanted the long-rangebomber in service at the earliest possible dateand Junkers was instructed to start production as soon as was practical. Subsequently,two huge bomb-proof underground hangarsnear Kahla were prepared for manufactureand assembly, while suitable runways werebuilt at the site to facilitate testing. It is possible that some rudimentary construction ofthe first Ho XVIIlb was underway when thewar ended and the RLM expected this prototype to be completed during autumn 1945,which seems to have been very wishful think-


I30Ft 6in (929m)I88.84ft' (I 754m')17Ft 8in (538m)4,6201b (2,095kg)342mph (550kph)I xWalter HWK R.1-203 liquid fuelrocket engine providing amaxthrust of 6611b (2,94k )

CrewWingspanWing areaLengthWeightMaximum peedPowerplant

Below left: Alexander Lippisch's Delta lYc,which received the official designation DFS39.The Delta lYc was the final incarnation of thissmall flying wing. The aircraft handled welland was considered extremely stable, providinginvaluable aerodynamic data for the Projekt Xprogramme, which eventually resulted in theMesserschmill Me 163 rocket-powered interceptor.Bill Rose Colleclion

Messerschmitt Bf 110 twin-engine fighter. TheMe 163A performed well, although therewere landing problems due to its very nat gliding angle. With a sinking speed of about 5ft(1.52m) per second at 137mph (220kph) andlack of naps, precise touchdowns were verydifficult and this led to a couple of potentiallydangerous incident .

By mid-1941, the first two Me 163A prototypes (Vl and V4) had undergone minormodifications and were taken to Peenemunde-Karlshagen for installation of theirWalter HWK RIl-203b rocket engines and further testing. The fuel used by the RIl-203b was

DFS 194

Below: One of the Projekt X wind-tunnel testmodels built during the late 1930s. It bears a closeresemblance to the final design and is seensuspended upside down, which was standardpractice during these trials. Bill Rose Collection

als and minor variants that are too numerousto list, but all adhered to the same basicdesign philosophy.

Development of the interceptor continuedfor some time after the Me 163A had beenselected for prototyping. Two variants considered by Lippisch in 1941 utilised the same overall dimensions as the Me 163, but differed in thecockpit arrangement. The P.01-117 was conceived with a nush, pressurised cockpit,accommodating the pilot in a prone po itionand P.OI-118 was to have a complicated internal arrangement that allowed the pilot toswivel for the optimal position. Both thesedesigns received serious consideration, butnei ther was accepted for further development.

Lippisch also examined the possibility ofproducing a turbojet version of the Me 163after early details of production jet engineshad been reviewed. This resulted in severalproposals and the most notable was the P.OI115 conceived in mid-1941 that would bepowered by a BMW003 engine. This aircraftwas similar to the Me 163, but the fuselagewas broader along its entire length and therewas an engine intake above and behind thecockpit canopy. A supplementary rocketengine was also considered as an option.Nothing came of these studi s, but the ideawould resurface in the future.

With construction of the first Me 163A prototypes at an advanced stage, work began onformalising the rocket-propelled interceptorthat received the reference Me 163B. Thisdesign resembl d the Me I 63A, but it wouldsteadily evolve into a new aircraft during themonths that followed. Me 163A VI was completed in early 1941 and transported to Lechfeld for unpowered glide tests. Dittmar newthe aircraft which was towed into the air by a

DFS 194 was adapted to accept a WalterRI-203 rocket engine, modified to provide areduced maximum thrust of 660 Ib (2.93kN)for the purpose of improving endurance.When the work was completed in early 1940,the DFS 194 was transported to PeenemundeKarlshagen where the engine was installed.

Heinrich 'Heini' Dittmar was the test pilotassigned to this project. He began with glidingtrials which graduated to powered nights(after being towed into the air), followed bysharp starts (on the ground) using the rocketengine. Initially, the speed was limited toabout 190rnph (300kph), but Dittmar hadsoon pushed this to 342mph (550kph). Theconstruction of two Me 163A prototypes wasnow undelway at Augsburg and althoughProjekt X was highly classified, the programme did not receive priority, so assemblyof these aircraft was slow with much of thework only taking place when skilled personnel could be spared from the Messerschmittproduction lines. Because the rocket-powered Heinkel He 176 had proved disappointing, there was half-hearted official interest inProjekt X. But once reports of the DFS 194 trials at Peenemunde-Karlshagen reached theRLM, there was an abrupt change of attitude.Lippisch was now receiving the kind of support he needed with the RLM deciding thatDepartment L would receive more staff andthe number of prototypes should beincreased to six.

Lippisch had initially considered a militaryadaptation of the DFS 194 which progressedto a more refined proposal known as P.O I-Illthat was completed in September 1939. Hisdesigners then began to consider an armedversion of the more sophisticated Me 163Aprototype. This resulted in a series of propos-

Messerschmitt Me 163

In the late 1930s, Heinkel at RostockMarienehe secretly built a small experimentalrocket-powered aircraft called the He 176.The He 176 new and was not a great success,but it indirectly led to a separate RLM sponsored rocketplane programme called ProjektX that was undertaken by Dr Alexander Lippisch and his team at DFS. Lippisch had produced an advanced tailless glider known asthe DFS 40 and his new rocket-propelleddesign was partly based on this aircraft. In1938, an area of the DFS facility was preparedfor assembly of the mainly wooden prototypethat had been given the reference DFS 194.But working space was extremely limited andit was agreed that only the wings would bebuilt at DFS and Heinkel would assist withconstruction of the fuselage.

Because the project was classified as topsecret, there were security restrictions thatbegan to cause problems, so the RLMdecided that Lippisch and his team of 12 engineers would move to Messerschmitt at Augsburg. This took place on 2 January 1939 andProjekt X was able to continue in an enclosedenvironment with less outside meddling. Lippisch's group was assigned a new designoffice called Department L and the relocationseemed to work well, although Willy Messerschmitt considered this an unwelcome imposition from the outset.

The DFS 194 had been largely completed atDarmstadt by the time Lippisch and his staffmoved to Messerschmitt, so the airframe wastransported to Augsburg where it was finished by skilled assembly workers borrowedfrom the Bf 110 production line.

Lippisch had originally intended to test theDFS 194 with a piston engine driving a pusherpropeller, but this idea was dropped and the

cycle undercarriage was planned and thewing profile remained very similar to thewartime bomber design. But the Frenchauthorities finally concluded that the projectwas too ambitious and cancelled it on IDecember 1948.

At this time, Hertel was working with theGerman scientist Dr Helmut Zborowski whowas in the process of setting up an aviationdesign consultancy at Brunoy called BureauTechnique Zborowski (BTZ). But Herteldecided not to remain in France and hereturned to West Germany during 1950,accepting an academic post at the BerlinTechnical University. In 1959, he joinedFocke-Wulf in Bremen where he worked as adesign consultant until his retirement.c

Dr Heinrich Hertel's 1946 proposal to SNCASE(Societe Nationale de ConstructionsAeronautiques du Sud-est) for a flying wingresearch aircraft based on wartime researchin Germany. Issued with the reference SE1800,the project received approval in 1947, but wasnever built. Bill Rose olleclion

would be fitted with a single upright stabilising fin and rudder with support on the groundprovided by a robust tricycle undercarriageand two-wheel nose unit and four wheels oneach main strut. It was also suggested thatsmall outrigger wheels might have beenrequired during landings.

Assistance with the aerodynamics for thisdesign was provided by DFS and an initial proposal was submitted to the RLM in the lastmonth of the European war although nothingcame of this very ambitious project. However, the story did not end there and whenhostilities ceased Dr Hertel was recruited bythe French to work on new aircraft projects.

In 1946, the Marignane design office ofSociete Nationale de Constructions Aeronautiques du Sud-est (S CASE) began to consider various ideas for a nying wing researchaircraft and Dr Hertel took the opportunity topropose a design that drew heavily on hisVLRB study. S CASE was impressed withHertel's ideas and assigned the project reference SE.1800. Official approval was grantedon 30 April 1947 (Document No 07776) withthe aim of drawing up plans for a tailless subsonic nying wing aircraft.

This was almost a twin-engine, one-thirdsize demonstrator version of the large nyingwing bomber that Hertel designed in 1945.

It was hoped this study would lead to several military options, which included a highperformance transport aircraft with a grossweight of 250 metric tons and a heavy fighterwith a cruise speed of 600mph (970kph) anda range of 2,050 miles (3,300km). In appearance, SE.1800 was more elegant than theVLRB. It had a contoured cockpit and engineintakes in the wing root leading edges. A tri-

, ,\ .....'

(70

I (possibly 2)55Ft 9in (17m)785ft' (73m')45' (leading edge)39Ft 6in (12m)20,0861b (9, III kg)33,0691b (15,000kg)621 mph (I,OOOkph)2hours2x Rolls-Royce ene turbojetrated at 5,000 Ib (22.2k ) staticthrust, or 2xS ECMA Alar 101turbojets, initially rated at 3,700 Ib(l6.45kN) static thrustNone

8-10168ft3in (51.2m)45' (leading edge)II ,840Ft' (I, 100m')101Ft 8in (31m)198,360 Ib (88,974kg)47Ib/rt' (231 kglm')8xHeinkel He SOIIA turbojetrated at 2,8651b (12.74kN) staticthrust or 8xJunkers Jumo 109012turbojets640mph (I ,030kph)Unknown10,557 miles (17,000km)Defensive cannons in upper andlower remote controlled turrets.17,6361b (8,000kg) bomb load

Project SE.1800

Armament

CrewWingspanWing areaSweepLengthEmpty weightGross weightMaximum speedEndurancePowerplant


Junkers Very Long Range Bomber (VLRB)

CrewWingspanSweepWing areaLengthGross weightMax wing loadingPowerplant

54 Secrel Projects: Flying Wings and Tailless Aircraft German World War 2 Flying Wing Development 55

nI IIIU

I30ft6in (93m)186ft' (17.27m')22' (leading edge)5.0:118ft lOin (57m)9ft lOin (3m)5, 7071b (2,588kg)7,9961b (3,628kg)560mph (900kph) at altitude60fVsec (I mlsec)38,000ft (I 1,582m)584 miles (940km)I xJunkers Jumo 004B turbojetrated at 1,980 Ib (8.8kN) staticthru t2x20mm Mk I03 cannons and2x30mm Mk I08 cannons

I33ft lin (10.08m)215ft' (19.97m')23' (leading edge)21ft (64m)7,9361b (3,600kg)One Heinkel He SOIIA turbojetratedat2,865Ib(1274k)static thrust621mph (I,OOOkph) approx2x30mm Mk I08 cannons in thefuselage and 2x20mm MG 151cannons in the wings

", ,"

riI IU

Lippisch P.IS

Messerschmitt (Lippisch) P.20

Armament

CrewWingspanWing areaSweepLengthGross weightPowerplant

CrewWingspanWing areaSweepAspect ratioLengthHeightEmpty weightGross weightMaximum speedRate of climbCeilingRangePowelplant

Maximum speedArmament

The elegant and compact Lippisch PI5 'Diana'fighter proposal, conceived to use readily availablecomponents produced for aircraft like the Hel62jet fighter. Although ordered into productiontowards the end of World War 2, the PI5 neverprogressed very far. Bill Rose Collection

ward cockpit and fuel tanks. Like the Me 334,this design would also use a fully retractabletricycle undercarriage. Performance estimates were very good for this proposal with amaximum speed of 568mph (914kph), a ceiling of 40,000ft (12,192m) and a range inexcess of 500 miles (800km). Armed with two20mm and two 30mm cannons, the P.20might have been a very effective low-cost jetinterceptor that would have been superior tothe later He 162 and perhaps safer to ny. However, a company review compared the P.20 tothe rival twin-jet Me 262 and Lippisch's proposal was dropped.

Soon after this, on I May 1943, Lippisch leftMesserschmitt to become Director of theVienna Aviation Research Institute and mostof his staff went with him. It was undoubtedlyfor the best as Lippisch was no longer onspeaking terms with Willy Messerschmitt.

Dr Lippisch designed one further verypromising warplane that was related to theMe 163. III early 1945, he was officiallyrequested to develop an inexpensive alternative to the Heinkel He 162 jet fighter that couldbe easily assembled from readily availablecomponents. He responded by proposing amore streamlined version of the P.20, whichevolved into a fighter called the P.15 basedaround a new fuselage containing a HeinkelHe SOIIA turbojet, mated to the forward section of a Heinkel He 162. A tricycle undercarriage would be used, employing the mainwheels from a Messerschmitt 8f I 09 and thewings and tailfin would be very similar tothose built for the Me 163C. Intake for the jetengine would be in the wing roots and thefighter would be armed with two or four can-

that the wing profile of the forthcomingMe 1638 required alteration to protect againstwingtip stall. This resulted in special fixedslots being fitted to the outer wing section justahead of the elevons. Although production ofthe Me 1638 began on I December 1941,there were continuing problems with development of the higher performance 'Hot' WaIter HWKI09-509A rocket engine. The tricky ZStoff catalyst had now been replaced with amixture of methyl alcohol, hydrazine hydrateand water called C-Stoff, but Walter's scientists at Kiel had run into major difficulties withthe new engine. This meant that when thefirst Me 1638 rolled off the production line inApril 1942, there was no propulsion systemfor it. It would be another year before theseproblems were resolved and late July 1943before the new engines were delivered.

The Me 1638 differed considerably fromthe Me 163A and it was designed to carrymore fuel which improved the maximumspeed, ceiling and range. It was initiallyintended to arm the aircraft with two 20mmMG 151 cannons, but these were laterreplaced by more effective 30mm Mk 108 cannons. The cockpit was unpressurised andpressurisation was considered unnecessaryfor a relatively short duration mission with thepilot using a face mask. It was also decided toinstall a substantial amount of forward andrearward armour. However, the unsatisfactory two-wheel dolly that dropped away aftertake-off was retained and the aircraft wouldland on a deployable skid and tail wheel.

Difficulties with development of the moreadvanced rocket engine encouraged Lippisch to design an alternative 'contingency'propeller-driven version of the Me 1638which was assigned the reference Me 334.This aircraft would utilise some of the existingMe 1638 components and could be assembled on existing production lines. A forwardlocated 1,475hp (I, I OOkW) 12-cylinder pistonengine would drive a rear-mounted threebladed pusher propeller. The Me 334 wouldbe equipped with a fully retractable tricycleundercarriage and a tailfin and rudder werepositioned beneath the rear of the fuselage,offering some protection to the propellerblades during take-offs and landings.

Lippisch also designed a jet-poweredMe 1638, which undoubtedly drew on earlierstudies. This proposal was called the P.20 andit would be propelled by a single Jumo 0048turbojet, rated at 1,980 Ib (8.8kN) static thrust.With an engine intake in the lower nose, thefuselage dimensions remained similar to theMe 1638, but there was just enough space toaccommodate the Junkers turbojet whichhad a length of 12ft 8in (3,85m) plus the for-

I30ft 7in (9.32m)199 13ft' (I 849m')23.3' (quarter-chord)18ft 8in (573m)9ft (276m)4,200 Ib (1 ,905kg)9,500 Ib (4,309kg)596mph (959kph) at altitudeI I ,500fVmin (3,505m/min)39,000ft (I 1,887m)7min 30sec50 miles (80km)1xWalter HWK 509A-2 liquid fuelrocket engine providing amaxthrust of 3,750 Ib (I668kN)2x20mm MG I51 cannons with100rpg or 2x30mm Mkl08cannons with 60rpg

Me 163A V4 making a rocket-powered take-off.Bill Rose Collection

ated to a speed of 624mph (I ,004kph) wherehe ran into severe stability problems and hadto throttle back. He had broken all existing airspeed records by a significant margin, but theachievement remained secret. Meanwhile,the RLM was so impressed by the night theyordered the newly designed Me 1638 intoimmediate production.

Having analysed the problems encountered by Dittmar, Lippisch's team decided

Accidents, sometimes with fatal consequenceswere continual throughout Germany's rocketinterceptor programme, primarily due to theextremely dangerous fuels used to power therocket engine. This photograph is believed to showMe 163A (GG-EA) V5 after an incident atPeenemiinde. Bill Rose Collection

The first prototype Me 163A (Werk Nr 163000000 I)assigned the reference V4, which made its initialtest flight at Lechfeld in spring 1941.Deutsches Bundesarchiv

Me 163B-IA

Armament

CrewWingspanWing areaSweepLengthHeight (on dolly)Empty weightGross weightMaximum speedRate of climbCeilingPowered enduranceRangePowerplant

thrust produced by these early engines wasconsiderable and the Walter RII-203 provideda controlled output that could be varied fromabout 330 Ib (I.46kN) to 1,650 Ib (733kN).

Powered nights began during September1941 and on 2 October 1941 the fully-fuelledMe 163A V4 piloted by Dittmar was towed intothe air behind a 8f II OC and released at analtitude of 13,124ft (4,000m). Dittmar thenignited the Walter rocket engine and acceler-

a mixture of highly corrosive concentratedhydrogen peroxide (T-Stoff) and a calciumpermanganate liquid catalyst (Z-Stoff), whichconverted the hydrogen peroxide to a hotsteam. This was a truly dangerous blend thatcould easily explode, even when carefullyhandled by highly trained operatives. Suchwere the hazards posed by the use of Z-Stoffand its tendency to clog jets that a replacement was urgently sought. Nevertheless,


A Me 163B interceptor during take-off. Like theearlier Me 163A, it had a two-wheel dolly that wasdropped after leaving the ground and the aircraftwould make a glide landing, touching down on adeployable skid and tail wheel. This saved weightavoided the need for a complicated undercarriage.Bitt Rose Collection

lence in the fuel outlet. Luftwaffe pilotsassigned to EK16 were being trained to fly theMe 163A gliders and by autumn 1943, a significant number of production Me 163B aircrafthad been completed at Regensburg. However, a B-17 bombing raid on 17 August 1943resulted in most of the remaining airframesbeing destroyed and production was passedto Klemm Technik GmbH which would coordinate dispersed production of componentsin much smaller facilities. The Me 163B hadnow received the name Komet (Comet),although pilots often referred to the aircraftwithin the EK16 as 'The Powered Egg' or 'TheDevil's Sledge'.

The best way to deploy the new interceptorremained under consideration and Hauptmann Spate proposed a chain of bases for theaircraft, each separated by a distance ofabout 90 miles (I50km). The rocket fighterswould attack the increasing waves of Alliedbombers during the inbound and outboundstages of their missions.

The Luftwaffe accepted aspects of the proposal with new bases being selected atWittmundhafen, Udetfeld, Stargard, Deelen,Husum and Venlo. The first functional rocketfighter staffel (squadron) known as I/JG400was created during May 1944 and based atWittmundhafen with most of the personnelbeing drawn from EKI6. But the combatready aircraft did not arrive until July 1944 andthen a decision was taken to relocate operations to Brandis Airfield near Leipzig because

rocket engine. This was intended for use inthe enhanced Messerschmitt Me 163C thatentered development after Lippisch and histeam left Messerschmitt. Three Me 163C prototypes were completed by Messerschmittand had been test flown by 1945. This aircraftwas a considerable improvement on theMe 163B with a lengthened fuselage and pres-

ble and Allied fighter pilots identified thisweakness, realising that the best time toattack one of the rocket fighters was during itsglide back to base.

Work continued to improve the rocketfighter and two Me 163Bs (V6 and V18) underwent modifications to accept the more powerful two-chamber Walter HWK 109-509 C

protection of the local Leuna synthetic fuelplant had been given high priority. Brandiswas relatively small and a second-rate airfield- workshops were inadequate, general facilities were poor and there was nowhere safe tostore the dangerous fuels used by the Kometswhich had to be shipped to the airfield by rail.Furthermore, the Leuna facility was close tothe limits of the Komel's range. lt was a veryunsatisfactory situation, but Brandis stillbecame the centre of Komet operations during the remainder of World War 2.

There had been one or two fleetingencounters with Allied aircraft, but the firstoperational mission took place at the end ofJuly and several kills had been recorded by.the beginning of August 1944. By now, theshortcomings of the Me 163B were becomingapparent and the high approach speed duringan attack made it difficult for pilots to hit theirtargets. Additionally, the Mkl08 cannonswould often jam.

Attacking the bomber formations at highspeed with cannon fire presented variousproblems and consideration had been givento the use of air-to-air R4M rockets. EKI6undertook trials with an adapted Me 163A thatwas fitted with underwing racks carryingR4Ms, but this did not work out and the ideaseems to have been abandoned.

A somewhat different and rather unorthodox idea was then adopted which involvedthe use of 10 upward-firing 50mm projectilesconfigured to be recoilless by simultaneouslydischarging a downward counterweight. AKomet equipped with this system would passbeneath the enemy bomber at high speed anda photoelectric cell would automatically trigger the release of the projectiles at exactly theright moment. Known as the SG-500 Jagdfaust(Fighter Fist), this weapon had been fitted to12 Me 163Bs by the end of the war and wasused operationally with Lt Fritz Kelbs shootingdown a B-1 7G during an interception.

Aside from that, the Me 163B's combatrecord was poor. It is hard to determine theexact number of kills that can be credited tothis aircraft, but it is certainly no more than ISand the majority were USAAF B-17s.

Although the Me 163 enjoyed an astonishing rate of climb and maximum speed, thefuel burnt at a phenomenal rate of 18.31b(8,3kg) per second, leading to rapid depletion. Then the aircraft became very vulnera-

A Me 163B glides back to base after an operationalflight. Bitt Rose Collection

A Me 163B caught by the gun camera of a USMFP-51 Mustang fighter just before it was shot down.USAAF1

32ft 2in (9.8m)219.583ft' (20.39m')23ft lin (7m)10ft (3m)4,8501b (2,199kg)11 ,6841b (5,299kg)569mph (9l5kph)40,000ft (I 2, 192m)12 minutes78 miles (I25km)I xWaiter HWK 509C-lliquid fuelrocket engine providing a maxthrust of 4,41 0Ib (I 9.61 kN)2x20mm MG 151 cannons with100rpg or 2x30mm Mk108cannons with 60rpg

Armament

Me 163C

CrewWingspanWing areaLengthHeight (on dolly)Empty weightGross weightMax speed at altitudeService ceilingPowered enduranceRangePowerplant

into the air by a Bf II O. By the start of the following year, an evaluation unit known asErprobungskommando 16 (EKI6) had beenassembled at Peenemtinde-Karlshagenunder the leadership of Hauptmann Wolfgang Spate who would go on to become oneof Germany's most highly decorated pilots.Soon after their formation, EKI6 was relocated to the Bad Zwischenahn Airfield northwest of Oldenberg.

Hanna Reitsch was also involved with earlytesting of the Me 163 and had been assignedthe task of conducting acceptance flights foreach Me 163B that left the Regensburg production line. On 30 October 1942, she made aglide test with the fifth aircraft, but the undercarriage dolly failed to separate. Reitsch wasforced to make a crash landing and it put herin hospital for many months.

Accidents with these aircraft were common and test pilot Heini Dittmar was badlyinjured during an uncontrolled Me 163 crashlanding on a section of concrete apron. Thesudden 20G deceleration caused him seriousspinal injuries which confined him to hospitalfor the next two years. His deputy RudolphOpitz also experienced a very hard landing ina defective Me 163, and although not sosevere, it kept him in hospital for severalmonths. The accidents were investigated byDr Justus Schneider, who was a consultantworking for the Luftwaffe, and he made anumber of recommendations. As a consequence, there were attempts to improve thelanding skid and make it more capable ofabsorbing severe impacts, but this turned outto be more difficult than envisaged. Attentionthen switched to redesigning the pilot's seatto make it torsion-sprung and this became astandard feature for all Me 163 aircraft.

Walter rocket engines were now installedin the Me 163B aircraft and tested, althoughfrequent problems arose with their operationsuch as the engines cutting out due to turbu-

Unquestionably the most famous German pilot ofthe Nazi era, Hanna Reitsch was involved with thetesting of several advanced military aircraft andsuffered serious injuries in 1942 after crashlanding a defective Me 163B. Bill Rose Collection

nons. Bearing some resemblance to theMe 163 series of designs, this hybrid taillessaircraft offered a good combination of features and it received the name Diana. Production was assigned to Wiener NeustadtAviation, but the P.15 Diana progressed nofurther than a scale model by the end of thewar.

Development of the Me 163B had beencomplex and troublesome, but the first production aircraft was test flown as a glider on26 June 1942 at Lechfeld, having been towed


Me 263A-l/Junkers Ju 248 VI

surised cockpit. A landing skid was still used,although the tail wheel retracted. Armamentwas similar but it was planned to fit theMe 163C with the SG-500 Jagdfaust system.The Me 163C addressed some of the earliercriticisms and in overall terms the aircraft wasan improvement over the Me 163B, but theLuftwaffe was unimpressed, mainly becausethe aircraft retained the landing skid system.This saved weight and avoided the need for acomplicated undercarriage, but it was possible for a dolly to bounce up from the groundafter release and hit the aircraft, or fail todetach, which could be almost as bad.

Using a landing skid also created groundhandling problems and could leave the aircraft vulnerable to attack prior to retrieval.Messerschmitt responded to these concernsat the end of 1943 with proposals for a moreadvanced aircraft that would be built alongside the Me 163C. Designated as the Me 1630,this new design was wind tunnel tested inmodel form and then a wooden mock-upwas built and shown to RLM officials. Immediate approval was given to proceed with theconstruction of a prototype and this aircraftwas completed by spring 1944 with glidingtests following within a matter of weeks. TheMe 1630 VI was essentially a stretched version of the Me 163B with a similar cockpitarrangement, a fully retractable tricycleundercarriage, the improved two chamberWalter rocket engine and larger fuel tanks.

But the RLM were not entirely satisfied withthe Me 1630 VI and voiced concerns thatMesserschmitt resources had become toostretched to continue with the project. It was

I31 ft 2in (9.50m)190ft' (17.7m')19ft lOin (6.05m)8ft IDin (2.70m)

I31 ft 2in (9.5m)191ft'(177m')19ft lOin (6.05m)8ft lOin (270m)3,3181b (I,505kg)8,5651b (3,885kg)559mph (900kph)at 30,000ft (9,144m)9,113fVmin (2,777mJmin)39,000ft (11,887m)5min 30secI xMitsubishi KR I0(Tokuro·2or Ro.2) liquid fuel rocket engineproducing 3,300 Ib (l47kN)of thrust(J8M I) 2x30mm Type 5cannon(J8M2) I x30mm Type 5cannon(Ki-200) 2x30mm Ho·1 05 cannon

MXY9 Shuka (Autumn Fire) received someconsideration by the Navy. This versionwould utilise a Kugisho Hatsukaze II(Tsu-II) ducted fan jet engine, although itnever progressed beyond the concept stage.The Navy was also planning to build a derivative of the Shusui called the J8M2 whichwould only be fitted with one cannon to allowthe carriage of a greater fuel load.

CrewWingspanWing areaLengthHeight

Mitsubishi J8M Shusui (Sharp Sword)

Yokosuka MXY8 Akigusa (Autumn Grass)Training Glider

CrewWingspanWing areaLengthHeightEmpty weightLoaded weightMaximum speed

Rate of climbCeilingPowered endurancePowerplant

Armament

for test nights while development continued.Fuel for the rocket engine was identical to theGerman C Stoff and T Stoff, referred to inJapan as Ko and Otsu. The Imperial JapaneseNavy received priority and the first pre-production J8MI came off the Mitsubishi production line at Nagoya in June 1945. It wasthen transported to Yokosuka where a rocketengine was fitted. With half full fuel tanks, thefirst Shusui night took place on 7 July1945.The project's senior test pilot ToyohikoInuzuka made a sharp start and left theground, successfully jettisoning the undercarriage and pulling up into a steep 45° climb. Butseconds later, the rocket engine cut out andthe aircraft stalled.

In the first account of this accident, the aircraft went into a steep vertical dive, hit theground and Inuzuka was killed instantly.Alternatively, it has been suggested that hemanaged to glide back to the airfield, butstruck the roof of a small building on theperimeter and crash-landed. The prototypecaught fire and Inuzuka was rescued but diedthe following day. Whatever the exact courseof events may have been, this accident was asetback to the programme. Engineers finallyconcluded that there were problems with theengine's automatic cut-out system, probablycaused by an air lock in the fuel supply, resulting from the tanks only being partially filled.Urgent modifications were made to thedesign of the engine, although this does notappear to have held up aircraft production atMitsubishi.

It was planned to have the first Shusui interceptor unit operational by the beginning of1946, but Japan had surrendered before thenext test night could take place. By the end ofthe war, approximately 50 gliders had beencompleted and seven or eight Shusui aircraftbuilt. A development of the glider called

A Japanese MXY8 Akigusa (Autumn Grass) trainingglider built by the Naval Arsenal in Yokosuka.Bill Rose Collection

B-29 raids were now underway and therewas an urgent need to produce an interceptor capable of engaging these fast, high-nyingbombers. Something had to be done andthere was general agreement that waiting forthe next submarine to arrive was not anoption. After some discussion, it was decidedto build a reasonably authentic copy of theMe 163B based on available information. Itwas felt that there should be no significant differences with the specification as the Messerschmitt aircraft was a proven design.

Mitsubishi was immediately assigned thetask of developing the aircraft and the projectwas co-ordinated by Kiro Takahashi and Tetsuro Hikida. This design was given the designation J8M I and would receive the nameShusui (roughly translated as Sharp Sword).By September 1944, a mock-up had beencompleted and by October 1944, severalmodifications had been made (mainly to simplify production) with approval to commenceimmediate production. Alongside this project, a glider for training nights was beingassembled at the Naval Arsenal in Yokosukaunder the direction of Hidemasa Kimura. Thisreceived the designation MXY8 and wascalled Akigusa (Autumn Grass). MXY8 wascompleted by the end of the year and testnown at the Hyakurigahara Airfield by Lt CdrToyohiko Inuzuka. He reported that the gliderhandled very well and as a consequence twofurther MXY8 gliders were built and suppliedto the Army and Navy for further evaluation. Atthe same time, a manufacturing contract wasissued to Yokoi Koku KK to begin manufacture of a production glider called Ku 13.

Work was now proceeding at Mitsubishi onthe construction of 12 J8M I (Ki-202) prototypes which externally resembled the originalKomet, but differed in certain detail such asthe lack of a small nose airscrew to drive agenerator. Two slightly different versions ofthe aircraft would be manufactured for theArmy and Navy. Aside from minor differencesin the type of equipment carried, theweapons varied. The Navy's J8MI would beequipped with two 30mm Type 5 cannonsand the Army's version designated Ki-200would carry two 30mm Ho I 05 cannons,although it appears that neither of theseweapons compared to the German Mk I 08design.

During trials, the Mitsubishi KR 10(Tokuro-2) rocket engine based on the Waiter design delivered lightly less thrust thananticipated, but it was considered adequate

JapanDuring the Me 163's development, Japaneseofficials were invited to observe test nightsunder a joint technical exchange agreement.The Japanese were impressed with the aircraft and knew about America's forthcomingBoeing B-29 bomber which would presentinterception problems for existing fighters.Following a visit to Bad Zwischenahn airfieldin 1943 by the Japanese military attaches, acontract was signed for licensed productionof the Me 163B and its rocket engine. The Germans would provide blueprints, technicalmaterial, fuel formulations and allow inspection of the manufacturing facilities. In addition they would provide several fullyfunctional Walter rocket engines and one airframe with the deal being completed by IMarch 1944.

The Japanese 3,600 ton diesel-electric submarine 1-29 Matsu (Pine Tree) was used forseveral highly classified missions duringWorld War 2 and during December 1943, 1-29was sent to German-occupied France with aspecial delivery of rare metals and varioushigh-priority materials such as morphine. Thesubmarine arrived at Lorient on II March1944 and before returning to Japan, the boatwas loaded with a secret cargo that includedblueprints and technical documentation forthe Me 163, plus several examples of the Waiter HWK 509A rocket engine and possibly aMe 163B airframe. On 16 April 1944, 18 passengers boarded the boat and she slipped outof the port. 1-29 arrived at Singapore on 14 Julyand disembarked its passengers. Amongstthese was the Berlin naval attache EiichiIwaya, who had been involved in securing theMe 163 deal. He then new on to Japan and thespecial cargo remained onboard 1-29 forreturn directly to Kure, Japan. On 26 July 1944,1-29 was detected in the Balintang Channel byWilkin's USN Submarine Taskforce andattacked by the submarine USS Sawfishwhich fired four torpedoes at her. Three hit1-29 and she sank immediately.

Mitsubishi already had enough technicaldocumentation to begin producing copies ofthe Walter rocket engine (some sources indicate that an engine was already in its possession), but it had no aircraft capable of using it.With the disappearance and presumed lossof 1-29, its only reference material was aMe 163B handbook that had been provided toEiichi Iwaya. The accuracy of this claimremains open to question with one unconfirmed report suggesting that some of theMe 163B documentation plus a Walter rocketengine (and a Junkers Jumo 004 turbojet)were unloaded at Singapore and transporteddirectly to Japan.

then decided that further development of theMe 1630 VI should be passed to HeinrichHertel's design office at Junkers. The projectwas now renamed Ju 248 and Hertel's engineers made a series of immediate improvements. These included lowering of thefuselage dorsal section and revising the cockpit which they heavily armoured, pressurisedand covered with a blister canopy. Production aircraft would be built in three sectionswith a removable tail unit to facilitate easyengine maintenance. The wings were similarto those found on the Me 163B, but now usedautomatic slots and had larger naps. The aircraft was designed around the WalterHWK109-509C rocket engine, but allowanceswere made for upgrading to the moreadvanced BMW708 rocket engine whichpromised significantly better performanceand ran on S Stoff (mostly nitric acid) andR Stoff (crude oxide monoxylidene and triethylamine).

By August 1944, the Ju 248 Vl had beencompleted at Dessau, and soon after this,glide trials commenced using a Ju 188bomber as a tow aircraft. For each of thesenights the undercarriage was fixed in anextended position and the Ju 248 VI proved tohandle more safely than the Me 163 at lowspeeds. According to most reliable references, powered nights followed during September or October with speeds in excess of590mph (950kph) being attained. But therewere problems encountered as the centre ofpressure moved rearward beyond Mach 0.8and this was an issue that needed to beaddressed. Then a rather petty disagreementarose about the aircraft's designation andWilly Messerschmitt complained to the RLMwhich instructed Junkers to start using theoriginal reference Me 263.

At an RLM meeting in Berlin during December 1944, it was decided to press ahead withproduction of the new aircraft, althoughdevelopment slowed with other work takingpriority and serious fuel shortages limited further testing. When hostilities ended, theMe 263 VI was the only example to be completed, but airframes for the V2 and V3 hadreached an advanced stage of construction.When Soviet forces secured the Junkersplant, VI was shipped back to Russia, alongwith most of the documentation and manufacturing equipment. While the Komet wasimpressive for its time, this programme canonly be regarded as a failure, having divertedvaluable manpower and resources frommore worthwhile aircraft such as the Me 262jet fighter. When the final Me 163B rolled offthe production line in February 1945, about365 of these aircraft had been produced.

I31 ft 2in (9.5m)191.6ft'(17.8m')50725ft lOin (7.88m)lOft 5in (3, 17m)4,640 Ib (2, I05kg)11,3541b (5,150kg)621mph (I,OOOkph) (HWK509C-4)16,400fVmin (HWK509C-4)45,000ft (I 3,716m)13min90 miles (144km)I xWalther HWK509C-4 liquid fuelrocket engine producing amaxthrust of 4,4101b (19.6IkN),or I x BMW708 rocket engineproducing an estimated 5,500 Ib(2446kN) thrust2x30mm Mk I08 cannons with60rpg

Armament

CrewWingspanWing areaAspect ratioLengthHeightEmpty weightGross weightMaximum speedRate of climbCeilingPowered enduranceRangePowerplant


Post-War British Komet TrialsWhen the war in Europe ended, British forcesretrieved a great deal of German aeronauticalhardware for evaluation. The quality of theequipment varied from brand-new conditionto badly damaged, but almost anything ofinterest was transported to the Royal AircraftEstablishment (RAE) at Farnborough where itwas examined and tested by the secretiveExperimental Flying Department.

In May 1945, the RAE took delivery of anintact Me 163B, although the early history ofthis Komet remains unknown. It was assignedthe official UK serial VF241, partly repainted toshow RAF colours and the engine wasremoved. This space would be filled with testequipment and ballast. Wg Cdr Roly Falkundertook the first glide flights in July 1945,but there were problems with the aircraft'shydraulic system which held up testing for theremainder of the year. It was also decided bythe Ministry of Supply that there should be nopowered flights made in this aircraft as it wastoo dangerous. Whether or not this was evera serious consideration remains unknown.

Glide trials with VF241 resumed duringFebruary 1946 using a Spitfire IX as the towingaircraft. The flights were undertaken fromWisley Airfield in Surrey which was owned byVickers-Armstrong, but is now derelict. Laterflights were made at RAF Wittering, althoughit's not entirely clear why this more distantlocation was chosen. However, both siteswere able to provide a grass landing areawhich was essential for the Komet. Many ofthe flights were undertaken by senior RAE testpilot Capt Eric Brown, who is now creditedwith having flown more different types of aircraft than anyone else in history.

One of the purposes of these trials was togain experience with skid landing techniquesas the RAE was developing proposals for anexperimental swept-wing supersonic aircraftdesigned by the German engineers Hans

Multhropp and Martin Winter. It was hopedthat the Multhropp-Winter aircraft wouldreach at least Mach 1.26 and climb to an altitude of 60,000ft (l8,288m). This alternative tothe supersonic Miles M.52 that was underdevelopment carried the pilot in a prone position and utilised a landing skid system to minimise weight.

But on 15 November 1947, VF241'shydraulic landing skid failed as Browntouched down and the Komet was badly damaged. Brown was slightly injured, but the aircraft was a write-off. The supersonic projectwas cancelled at around the same time andthis would be one of the last captured Germanaircraft to be te t flown by RAE personnel.Nevertheless, the small rocketplane had quitean impact on British designers and it is clearthat the experimental DH.108 programme(described in the previous chapter) wasstrongly influenced by the Me 163. The idea ofa rocket-powered interceptor also persistedfor several years with the Me 163 making alasting impression on Britain's senior air staffwho were increasingly concerned about thethreat from future high-flying Soviet bombers.

The jet engine was still relatively crude,unreliable and incapable of delivering the kindof performance needed by an interceptor. Thisled to a requirement for an advanced purerocket-powered interceptor issued as Specification F. I 24. Several military aircraft contractors made submissions and the winner was anadvanced delta-winged design from Shortsknown as PD. 7. However, it was soon replacedby a proposal from Saunders Roe for a highperformance mixed propulsion interceptorcalled the SR.53 which was finally accepted fordevelopment under a revised SpecificationF. I 38. Two examples were built and therewere plans to progress to the Saunders RoeSR. I 77 which would enter service with theRAF, Royal Navy and Luftwaffe. The programme continued until the late I 950s when it

met with sudden cancellation during majordefence cuts. Since the SR.53's inception, gasturbine technology had made considerablestrides and as a consequence, combat aircraftusing rocket propulsion were effectively dead.

US KometsAt the end of World War 2, five MesserschmittMe 163B Komets were shipped to the US forevaluation by the USAAF. Each Me 163received a Foreign Equipment serial number:FE-495, FE-500, FE-50 I, FE-502 and FE-503. Ofthese aircraft, FE-500 (also marked T-2-500)was the example used for testing. ThisMe 163B-1a (Werke Nr 191301) arrived atFreeman Field, Indiana, on 10 August 1945and it was displayed at the Wright Field AirFair during October 1945. Following this, theaircraft was restored to fully operational condition using components salvaged from otherKomets and work was completed by March1946. FE-500 was then shipped to Muroc Field(now Edwards AFB), California, on 12 April1946. It was planned to test the Me 163B as aglider and then switch to rocket-powered trials, so a request was made to the US Navy fora supply of Hydrazine hydrate. Dr Lippischhad been detained in Austria by the USAAF'sAir Technical Intelligence branch and wastaken to Paris and London for debriefings. Hewas then offered the opportunity to work inthe United States along with senior membersof his staff that included Ernst Sielaff andFriedrich Ringleb under a scheme calledOperation 'Paperclip'.

Lippisch arrived in the US during January1946 and was then transferred to Wright Field(now Wright-Patterson AFB), Dayton, Ohio.One of the first programmes he was asked toparticipate in was a USAAF evaluation of theMe I 63B and on 30 April 1946, Dr Lippisch andformer test pilot Ludwig Vogel were flown toMuroc Field. The next day Lippisch and Vogelexamined FE-500 and pointed out variousfaults with the landing gear, control systemand wing delamination. This resulted inimmediate work on the aircraft, with thewings being replaced by those belonging toFE-495. The Komet was finally judged airworthy on 3 May 1946 and preparations weremade to undertake the first glide flight. MajorGustav E. 'Gus' Lundquist had also beenflown in from Wright Field where he headedthe Fighter Test Section and was assigned tomake the initial glide flights in FE-500.

Several Me 163B Komets were secured by theBritish during 1945 and the best example wasprovided to the RAE for testing and evaluation,having been given the reference VF241. The enginewas replaced with ballast and VF241 was partlyrepainted with RAF markings. Bill Rose Collection

At the end of hostilities in Europe, the US Armyshipped vast quantities of advanced Germanmilitary hardware back to America for evaluation.This included complete examples of aircraft suchas the Messerschmitt Me 163. Five of these aircraftare known to have been shipped to the US and thisphotograph shows one of these examples beingloaded into a Douglas C-54 transport aircraft. USAF

Restored to fully operational condition in the USA,this Me 163B was assigned the reference FE500and delivered to Muroc Field (now Edwards AFB),California, on 12 April 1946. It was flown as aglider and there were plans to test the aircraftunder rocket power, but the idea was finallyabandoned on the grounds of safety. USAF

The first attempt to fly the aircraft tookplace on 3 May 1946 at Rogers Dry Lake usinga B-29 bomber as the tow aircraft. But therewere problems with the tow cable beinginadvertently released and the trials weredelayed. When flight tests finally got underway, Lundquist experienced very seriouswake turbulence problems caused by theB-29, but he was lifted to an altitude of about32,000ft (9,753m) before gliding back to landon the lake bed.

Further flights were made and it wasplanned that Robert Hoover would fly FE-500under full rocket power, although it was finallydecided not to proceed for safety reasons.With the trials concluded, FE-500 was movedto orton AFB where it was stored until 1954and then handed over to the SmithsonianInstitution (now the National Air and SpaceMuseum). It remained on display until 1996when it was loaned to the Mighty Eighth AirForce Museum in Georgia which undertook afull restoration. At the time ofwriting it is in theprocess of being returned to the National Airand Space Museum's Silver Hill facility.

Details of this aircraft's earlier history inGermany remain unknown. As far as isknown, the other Komets taken to FreemanField had all been scrapped by the late 1940swith some of the parts being retained asspares for FE-500.

In addition to FE-500, two Japanese J8M 1Shusui aircraft were shipped to the UnitedStates onboard the USS Barnes in November1945. The first example received the serialFE-300 (or T2-300), but the reference for thesecond is unknown at present. This was brieflydisplayed at Naval Air Station Glenview, Illinois,and then scrapped. FE-300 was evaluated bythe Navy and then passed to the Planes of FameMuseum, California, where it currently resides.

In 1960, a J8M1 was discovered hidden in acave at the Yokosuka region south of Tokyo.Although in very poor condition, the aircraftwas displayed outdoors at a Japanese AirForce base near Gifu for many years. In 1999,Mitsubishi purchased this example and

undertook a full restoration which was virtually a complete replication. The aircraft is nowkept at the company's Komari Plant Museum.

Postwar Russian Komet ResearchIn early 1944, Mikoyan-Gurevich (MiG) and atleast one other Opytnoe KonstruktorskoeByuro (OKB or Experimental Design Bureau)were requested to start work on developing aRussian version of the rocket-poweredMe 163B interceptor. Proposals were drawnup, but further development had not beenapproved by the end of the war in Europe. Itremains unclear how similar this proposal wasto the German aircraft. After hostilities ceased,the Russians secured several examples of theMe I 63B, an example of the Me I 63S (two-seattrainer) and the very advanced Junkers248/Me 263V1 prototype. In addition to the aircraft, there were huge quantities of documents, factory equipment and engineers whohad worked on these programmes.

Many captured German aircraft of interest,including the German rocket fighters, weretransported to the Gromov Flight Research

Institute which had been established in 1941south-east of Moscow. But when it came totesting the rocket aircraft there was no fuel forthe Walter rocket engines and there wereinsufficient means within the Soviet Union orcaptured territories to produce the quantitiesof hydrogen peroxide required.

Nevertheless, glide flights began in 1945using a Tupolev Tu-2 bomber to tow aMe 163B into the air with M.L. Gallay becoming the first Soviet test pilot to fly the Komet.Further flights, with and without water ballast,were undertaken by institute pilots. It wassoon determined that the Me 163B could diveat higher speeds than any other unpowereddesign and it possessed good longitudinal androll stability. The institute's chief test pilot, LtCol V. Yeo Golofastov, remarked that theKomet behaved like a conventional fighter inunpowered flight and had good aerobaticqualities. However, it is clear that the Me 163Bwas not a popular aircraft with the Russianswho nicknamed it Karas (Carp) and none ofthem liked the landing skid system which wasblamed for several minor accidents.


In late 1941, Lippisch was advised about jetengine developments at Junkers and he produced preliminary designs for a twin-enginefighter called P.09 which utilised the Me 163'saerodynamics. Messerschmitt rejected theP.09 as it clashed with development of theMe 262, but Lippisch evolved the proposalinto a slightly larger two-man fast jet bombercalled the Li P.I O. By the end of 1941, the tailless P.I 0 had been given a wingspan of 43ftII in (13.4m) with a 33° sweep and the aircraft's overall length was 26ft 9in (7.5m).Gross weight was 24,2501b (II ,000kg) andtwo of the still experimental Junkers Jumoturbojets would be used for propulsion, alsoenclosed within the wing roots. It wasplanned to equip the aircraft with a fullyretractable undercarriage with the rear endrested on a tail wheel and the crew of twowould sit side-by-side in a flush cockpit. P.1 0would be armed with forward and rearwardfiring cannons and capable of carrying a2,2051b (I ,000kg) bomb load internally.

Dr Hermann Wurster produced a closelyrelated design with a different propulsion system and, rather onfusingly, this received thesame Lippisch P.I 0 reference (but probablyhad a different unknown suffix). This versionof the P.I 0 was to be powered by a centrallypositioned Daimler Benz 606 piston enginerated at 2,700hp (2,014kW) which connectedto a tail-mounted pusher propeller via a shaft.This P.l 0 utilised a similar undercarriage, hadthe same wingspan and a similar grossweight to the jet powered P.I O. It appears thatcockpit was only intended to accommodatea pilot. Both the jet and piston engine versionsof the P.I 0 design were conceived as potential successors to the unsatisfactoty Messerschmitt Me 21 0 heavy fighter and a thirdcontender known as the Me 329 (described ina later section) was produced by Messerschmitt's Dr Hermann Wurster.

With design work continuing on a new fastbomber that was adaptable to the heavyfighter role, Lippisch proposed the P.l1 in

During his time at Messerschmitt in the early1940s, Lippisch studied a number of designs forheavy fighters and light bombers with Dr RudolfRente!. The first series of proposals were for theLippisch Li P.04-106A to P.04-114A flying wings(most appear to differ only in minor detail)which were an attempt to produce a moreeffective competitor to the MesserschmittBf II 0 Zerstbrer (Heavy Fighter). The P.04I 06A's wing had an initial sweep of 13°, becoming 30° from ju t outside the engine nacelles.The aircraft was to be powered by two DaimlerBenz 60 I E engines each rated at 1,200hp(895kW) driving pusher propellers. Stabilisingfins and rudders were positioned on the wingsand the aircraft was equipped with a fullyretracting undercarriage that included anextending tailwhee!. The pilot was positionedright at the front of the cockpit, affording himgood unobstructed visibility and the radio operator/rear gunner faced rearward. Armamentwould consist of four fixed forward firing cannons and two rearward firing machine guns.This design would have provided some advantages over the Bf II 0, but it was not accepted forfurther development by the RLM.

Lippisch Heavy Fightersand Fast Bombers

believed that much higher Mach numberswould be possible with the right type ofpropulsion. One anticipated relatively shortterm development of the OM-I was a supersonic ramjet-powered interceptor that wasgiven the provisional reference P.13A.

When Germany surrendered, the OM-Iglider had almost been completed at Prienam Chiemsee in southern Germany. It wasthen secured by the US Army, which allowedcompletion of the project before shipping itback to America and ultimately NACA Langley. Lippisch's research data from this projectwould prove extremely influential with allpostwar American and British designers.

In a parallel programme, work was underway at the Mikoyan-Gurevich OKB to developthe captured Me 263 into a point defencerocket interceptor. This lead to an improvedversion of the aircraft called the MiG 1-270(Zh). It differed in a number of respects fromits German predecessor, having straight thinwings and a 30° swept tailplane. It was structurally superior to the Junkers prototype witha larger pressurised cockpit and the 1-270 wasthe first Soviet aircraft to be fitted with anejector seat. Had this design entered production it would have been armed with two23mm cannons and eight air-to-air rockets.

Two prototypes were built during 1946 withthe assistance of German engineers, althoughthe first aircraft had no engine and was onlyintended for glide trials so water was carriedas ballast. Test pilot Victor Yuganov flew thefirst MiG 1-270 during December 1946 with aTupolev Tu-2 used as the tow aircraft. The second 1-270 was completed at the beginning of1947 and was fitted with a two-chamberGRD-2M-3V rocket engine designed by LeonidDushkin and Valentin Glushko. This enginewas developed from an advanced design forthe experimental pre-war Soviet BI rocketplane, but probably utilised some later German engineering techniques. The GRD-2M-3Vwas fuelled with nitric acid and kerosene, providing a maximum thrust of about 3,190 Ib(14.2kN). Powered flights began in early 1947,but the second prototype was badly damagedafter Yuganov made a hard landing. Soon afterthis, the first prototype was seriously damaged in another landing incident. It was thendecided to abandon the project with rapidadvances being made in the field of turbojetpropulsion and the promise of effective surface-to-air missiles.

Built by students from the Darmstadt and MunichUniversities, the Lippisch-designed DM-1 wasexpected to lead to several supersonic combataircraft and become a successor to the Me 163B.Bill Rose Collection

Lippisch OM-lAlthough it barely qualifies for inclusion inthis book, Lippisch designed a very advancedpure delta shaped glider called the OM-I afterleaving Messerschmitt. The name of this aircraft reflected the fact that a group of talentedstudents from Darmstadt and Munich Universities were recruited to work on the projectunder his direction. The DM-1 was se n as astepping-stone to more advanced experimental aircraft powered by turbojet, rocketand ramjet engines. Wind tunnel testsshowed that this unusual design remainedstable at speeds up to Mach 2.6 and Lippisch

I19ft Sin (59m)21ft 7in (66m)10ft Sin (3.17m)65SIb (297kg)

I25ft Sin (7.75m)129ft' (12m')29ft 2in (8.91 m)10ft Iin (3.08m)3,4081b (I ,546kg)9,1501b (4,150kg)I x Dushkin-Glushko RD-2M-3Vliquid fuel rocket engineproducing 3,190 Ib (I4,2kN) thrust621mph (I,OOOkph)104mph (168kph)55,775ft (17,000m)13,800fVmin (4,220m/min)9min2x23mm Nudelman NS-23cannons with 40rpg and8xRS-82 rockets

Lippisch OM-l

The Messerschmilt Me 263 (top) was Germany'smost advanced wartime rocket-poweredinterceptor. It was built in prototype form andunderwent limited trials towards the end ofhostilities. This aircraft and much of the researchmaterial that fell into Soviet hands formed thebasis of the MiG 1·270 (centre). Although the MiGwas a considerable improvement over the originaldesign, it was eventually abandoned. Germany'sadvanced wartime rocket fighter programme alsomade a deep impression on British officials whocommissioned a series of studies for purely rocketpowered interceptors. The ultimate design toemerge was the high-performance Short PD7(boltom). However, it was soon realised thatdespite possessing phenomenal performancewhen compared to prevailing turbojet-poweredfighters, this type of aircraft was essentiallyimpractical due to its substantial fuelconsumption. The Short PD7 represents the mostadvanced and final pure rocket fighter concept ofany note. However, the British persevered withmixed propulsion until the late 1950s before finallygiving up on the idea. Bill Rose Collection

At the end of World War 2, Soviet forces captureda Me 263 prototype, research documentation anda number of German technicians. This led to aproject at the Mikoyan-Gurevich OKB to improveon the rocket fighter's design and build twoprototypes assigned the reference MiG 1-270.Bill Rose Collection

CrewWingspanLengthHeightWeight

It is not clear if this is the first or second MiG 1-270rocket-powered prototype interceptor, but itappears to differ in minor detail from photographsof the MiG 1·270 seen on the snow field.Bill Rose Collection

Mikoyan-Gurevich 1-270

Maximum speedLanding speedCeilingRate of climbEnduranceArmament (proposed)

CrewWingspanWing areaLengthHeightEmpty weightGross weightPowerplant

CJ

.--,.'.--..-....s-··..

CJ


accommodated in a spacious cockpit withstaggered side-by-side positions offeringgood visibility. The Me 329's wingspan wasslightly greater than the earlier LippischLi P.04 proposals or the later piston engineP.10 and propulsion would be provided bytwo Daimler Benz 601 or Jumo 213 pistonengines mounted within the wings and eachdriving a three-bladed pusher propeller withan 11 ft 2in (3.4m) diameter. As a consequence of this layout, the undercarriage wasa fully retracting tricycle design, although theamount of ground clearance below the propellers would suggest there was potential forserious problems in certain situations. TheMe 329 was fitted with a single swept tailfinand rudder and the aircraft's centrally locatedbomb bay could accommodate a 2,2051b(1 ,000kg) payload. Additional bombs, rocketsor fuel tanks could be carried externally.Armament comprised of four MG 151/2020mm cannons in the nose, possibly twoMkl03 30mm cannons in the wing roots anda remote controlled MG 151/20 20mm cannonin the tail. This would be controlled by thenavigator using a periscope aiming system.

A full-sized mock-up of the Me 329 was builtat Augsburg and comparative estimates suggested that the aircraft would have providedslightly better performance than the pistonengine Lippisch (Wurster) P.l 0 and was a significant improvement over the Me 41 O. Nevertheless, Willy Messerschmitt turned downboth designs, deciding to continue with development of the Me 41 O. lillie is known aboutthe history of the Me 329, but it appears thatdevelopment of this intere ting aircraft continued after Lippisch left Messerschmitt in 1943

Messerschmitt Tailless Designs

,dt T I,M"

manufacture the Delta VI prototypes andundertake production at their Berlin plant.

Lippisch had initially planned to have the jetpowered Delta VI-V2 ready for testing withinsix months, but there were major disagreements with Henschel and as a consequencethe programme slowed with Lippisch's engineers at Salzburg beginning work on construction of the VI prototype. By the end of thewar in Europe, wind tunnel tests had beencompleted and the mainly wood/plywoodfuselage of Delta VI-VI was largely finished. Itwas secured by American forces and mayhave been shipped to the US for evaluation.

Serious problems with the MesserschmittMe 21 0 fighter-bomber led Dr Alexander Lippisch's Department L and Dr HermannWurster's design office to initiate design projects that would produce a superior replacement. Lippisch started work on his P.I 0 seriesof proposals at the end of 1941, while Wurstercontributed with a single engine, tailless concept and separately developed a twin (piston) engine flying wing which was given thecompany reference Me 329. An additionalproject was already underway to re-engineand improve the Me 210, leading to theMe 41 0 Hornisse (Hornet).

Wurster's tailless Me 329 heavy/long-rangemulti-role combat aircraft would be mainlybuilt from readily available wood/plywoodand utilise as many off-the-shelf Me 21 0/41 0components as possible to limit productionrequirements. The pilot and navigator were

I52ft 6in 16m32ft 4in (9.85m)5705ft' (53m')24,250 Ib (II ,000kg)424mph (682kph)39,000ft (II ,887m)1,500 miles (2,42Ikm)I xcentrally located Daimler BenzDB606 pi ton engine (twoconnected DB601 engines)producing 2,700hp (2,013kW)2x forward firing 20mm MG 151cannons. 2x20mm MG 151rearward firing cannons in tail.2,2051b (I ,000kg)

I41ft 6in (12.65m)40 1.5ft' (37.3m')26ft 9in (8.15m)13ft 2in (4.0m)8,830 Ib (4,005kg)16,5351b (7,500kg)550mph (885kph) approx2xJunkers Jumo 004B turbojets,each rated at 1,980 Ib (8.8kN)static thrust2x20mm MG151/20 cannonin the wing root

I35ft 5in538ft' (50m')2.33:137' (leading edge)24ft 6in (7049m)9ft (2.76m)17,6361b (8,000kg)646mph (I ,040kph)40,000ft (12, 192m) estimated1,864 miles (3,000km) approx2xJunkers Jumo 004B turbojets,each rated at 1,980 Ib (8.8k )static thrust2x30mm MkI03 cannons, plusoption for two additional30mmMk I03 cannons or one 75mmBK 7.5 cannon in an external pack2,2051b (I,OOOkg)

CrewWingspanLengthWing areaGross weightMaximum speedCeilingRangePowerplant

Armament

Bomb load

Lippisch Delta VI

CrewWingspanWing areaLengthHeightEmpty weightGross weightMaximum speedPowerplant

Armament

Lippisch Li P.IO Piston Engine PoweredFast Bomber (May 1942)

Lippisch Li P.11 (December 1942)

CrewWingspanWing areaAspect ratioSweepLengthHeightGross weightMaximum speedCeilingRangePowerplant

Bomb load capability

Armament

The Me329, designed by Dr Hermann Wurster, wasbuilt as a wooden mock-up, but a prototype mayalso have been constructed and flown at theRechlin Test Centre in early 1945. Chris Gibson

autumn 1942. This might be regarded as afurther refinement of the tailless, jet enginepowered P.IO with some aerodynamicimprovements and a fully retractable tricycleundercarriage. Powered by two Junkers Jumo004B turbojets, the P.ll was to be a two-manaircraft with a tandem cockpit, forward firing20mm cannons and the same payload capability as the P.10. Refinement of the designcontinued into 1943 with significant changesto the wing profile, engine intakes and cockpit design, which was now reduced to just apilot. One unusual feature was the hinged stabilisers attached to the tailplane that could bebrought into a horizontal position.

Nothing came of this fast bomber projectwhich remained on the drawing board upuntil the time when Lippisch and his teamparted company with Messerschmitt andrelocated to Vienna. P.Il seemed to havebeen passed over for a bomb-carrying HortenHo IX, but Lippisch was then approached bythe RLM to continue work on P.ll and produce a new high-speed version of his aircraft.As the P.11 continued to evolve towards adelta shape, Lippisch assigned it a new reference - Delta VI. The initial prototype (VI)would be a glider and there would be theoption of configuring the aircraft as a heavyfighter or fighter-bomber. Following windtunnel testing of models, a mock-up wascompleted at the LFA (Aviation ResearchInstitute) in early 1944.

Delta VI was an impressive semi-delta wingdesign with a forward positioned cockpit, twoupright stabilisers and rudders and power provided by two centrally positioned Jumo 004Bturbojets. Rocket assisted take off was alsoconsidered as an option for short runwaysand/or heavy loads. The aircraft was supported on the ground by a robust retractabletricycle undercarriage and was capable of carrying the same payload as the earlier aircraft inthis series. One interesting suggestion was toequip the heavy-fighter version with a 75mmBK 7.5 cannon in an external pack for an antiarmour role. It is probable that 12 roundswould have been carried in the pack and thiscannon was able to penetrate 5in (130mm) ofarmour at a range of 3,280ft (J ,000m).

The aircraft appears to have been a promising design with available literature suggestingthat it would have been fast and manoeuvrable with a good range and the ability to beconfigured for a number of different roles.Naturally, low cost materials would havebeen used wherever possible in its construction. The RLM approved the Delta Vl andcommissioned the VI prototype and threepre-production aircraft for evaluation anddevelopment. Henschel was chosen to

244ft (1304m)33' (leading edge)26ft 9in (8.15m)9ft lOin (2.99m)570.5ft' (53m')UnspecifiedUnknown2xJunkers turbojets(based on prototype engines)2x20mm MG 151/20 cannon in thenose, and 2x20mm MG 151/20cannon in the tail.2,2051b (I,OOOkg)

Armament

Intemal bomb load

Lippisch Li P.I 0 Jet Powered Fast Bomber(November 1941)

CrewWingspanSweepLengthHeightWing areaGross weightMaximum speedPowerplant

Although nothing came of the Li PII fast bomber,Uppisch continued to evolve the design. The RLMapproved detailed design work on the new aircraftand Lippisch assigned a new reference, which wasDelta VI. Following wind tunnel testing, a mock-upwas built and the RLM prepared for production,but by then, the war was at an end. Chris Gibson

o Fl 10

r -," ,. "'1

1

The Uppisch Li PII was adesign for a twin-engine,tailless fast bomber thatemerged from Department L inlate 1942. Although never built,the design would progressivelyevolve during the course ofWorld War 2. Bill Ro e olleclion

J

Uppisch Li P.04-I06 Heavy fighter

252ft 6in (16m)19ft Iin (5.8m)IOft4in (315m)424mph (682kph)39,000ft (II ,887m)1,500 miles (2,414km)316mph (51 Okph)2x Daimler Benz 60 IEpistonengines each rated at 1,200hp(895kW)

Armament 4x forward firing MG 151 gunslocated on the fuselage sides and in the wing roots.2xremote-controlled MG 131 guns firing rearward

CrewWingspanLengthHeightMaximum speedCeilingRangeMaximum speedPowerplant


365Ft 7in (20m)

45° (leading edge)

I,292Ft' (I 20m')54Ft 5in (I6.6m)

14Ft 9in (4.5m)

77, 1611b (35,OOOkg)

4x Heinkel He SOIIA turbojets,

each rated at2,8651b (12.74k )

tatic thrust600mph (965kph)

45,OOOFt (13,716m) estimated

4,349 mile (7,OOOkm)

Unspecified forward and rearward

defensive cannons. Amaximum

bomb load of8,8181b (4,OOOkg).

Free fall bombs, 2x torpedoesor guided weapons

I30ft (9.14m)

45° (at 0.41 chord)

301ft' (28m')29ft 3in (8.9Im)

lOft (3.05m)

6,040lb (2,740kg)

9,4371b (4,2 Okg)

I x Heinkel He SOIl A turbojet,

rated at 2, 651b (I 274kN)

static thrust618mph (995kph)

46,OOOft (I4,020m)

4x 30mm MkI08 cannons

Messerschmitt P.1111

Messerschmitt P.II 08.11

Crew

Wing pan

SweepWing area

LengthHeight

Gro sweightPo\Verplant


Range

Armament


Armament

Crew

Wing pan

\Veep

Wing area

Length

Height

Empty weightGross weight

Powerplant

One of several advanced Messerschmitt flying wingbomber designs, the P.II08.1 I. On this version,the air inlets for the engines are located in theleading edge wing roots. These were relocatedon the following design to below the wings.Bill Rose Collection

~=======-==rslS=§I~ESI==2E1====::======0r'l. (''\I I I II I I'U U

"

less single engine jet fighter with the reference

P.III!. A single Heinkel He S OIl turbojet with

air intakes positioned in the leading edge wing

roots powered this compact design. A rela

tively low-profile canopy covered the pres

surised cockpit and an ejector seat was to befitted. P.IIII was fitted with a tricycle under

carriage and armament comprised of two

30mm cannons in the nose and two 30mm

cannons positioned just outboard of the air

intakes. The overall design was very cleanwith a single swept tailfin and it i believed that

aspects of this project innuenced develop

ment of the de Havilland DH.I 08.

P.IIII retumed good re ults as a wind tun

nel model, but the RLM expressed serious

concems about the unprotected fuel tankslocated in the wings considering this to be a

serious weakness. Subs quently, the design

underwent a significant I' vision and was allo

cated the designation P.1112. Main differ

ences with this aircraft were a redesignedwing with slightly less sweep and a reduced

span, plus a number of alterations to the

cockpit, moving it further forward. Perfor

mance was expected to be nominally better.

By the end of the war, work was well

advanced on construction of a mock-up at

Me serschmitt's Oberammergau workshops

and Dr Waldemar Voigt who headed this project had anticipated the first test night by

mid-1946. Completed ections of the mock

up and all documentation was captured by

US forces and shipped back to America forevaluation. The advanced P.II08 bomber

and P.1112 fighter tudies were the last pro

jects of any significance undertaken by

Messerschmitt before the war ended.

\465Ft 7in (20m)

45° (leading edge)

I,292ft' (I 20m')54Ft Sin (I6.6m)

19Ft 8in (6m)

4x Heinkel He SOIl A turbojet ,each rated at 2,8651b (I 2. 74k ')

static thrust600mph (965kph)

45,OOOFt (I 3,71 6m) estimated4,349 miles (7,OOOkm)

Un pecified forward and rearwarddefen ive cannons. Amaximum

bomb load of , 181b (4,OOOkg).

Free fall bombs, 2x torpedoes or

guided weapons

Messerschmitt P.II07

Crew

Wing pan

SweepWing area

Length

Height

Powerplant

1aximum peed

Ceiling

Range

Armament

turbojets and manned by a crew of four in a

pressurised cockpit. The aircraft would be

supported on the ground by a retracting tricy

cle undercarriage and the bomb bay would be

adaptable for a range of different ordnance.The materials used for construction would be

steel and duralumin around the central area

and mainly wood for the wings. The taille s

design for the P.II 07 study shown in drawing

IX-122 ( ee Luftwaffe Secret Projects: Strategic Bombers /939-/945 by Dieter Herwig and

Heinz Rode: Midland Counties Publishing)

appears to have had a 45° sweep and a

wingspan of 65ft 7in (20m). The overall length

was approximately 54ft 5in (l6.6m) and it was

equipped with a single tailfin and rudder, producing an overall height of about 19ft 8in

(6m). Four Heinkel He S OIl turbojets located

in the wing roots provided propulsion with

engine air intakes positioned at the inner lead

ing edge. In addition to meeting requirements

for a fast bomber, the P.Il 07 was to functionin maritime and reconnaissance roles.

Project P.II 07 had soon given way to a new

series of closely related designs called P.I 108

that included nying wing proposals which pri

marily differed in engine layout. Although sim

ilar in appearance to the original P.1107 taillessdesign, the definitive P.II08.11 underwent a

major engine bay revision with the air intak s

relocated beneath the wing. In addition, the

crew requirement was reduced to three. A

final proposal in this serie was an arrowhead

near-delta design with no upright control sur

faces and ach of the four engines slightlyangled inwards to reduce problems with

thrust equalisation. P.II 08 progressed no fur

ther than drawing and discussion and there

was no expectation of production before 1948.

Developed in parallel to the P.II 08 designswere a series of proposals for an advanced tail-

6-10 (depending on the mi ion)

166Ft (50.6m)

3,229rt' (300m')50Ft 4in (15.35m)

28Ft 3in (86m)

198,4141b (90,000kg)

400mph (643kph)

9,320 miles (I5,000km)

(as along range bomber)4x Daimler Benz DB615 liquid

cooled piston engine , each

producing 4,OOOhp (2,9 3kW). The

DB615 wa built from two DB614

engines and development \Vaabandoned in June 1942.

nspecified remote controlled

cannon in no eand tail unit

Tactical mis ion (I,550 mile /

2,495km), J10,230 Ib (50,OOOkg).

Long-range mis ion (9,315 mile14,991 km), 44,0951b (20,OOOkg)

Torpedoe ,mines or anti- hipping

guided weapon

4x 88mm Flak cannon

Messerschmitt MeP.08.01 Heavy Bomber

Powerplant

bomb/cargo bay. It was also suggested thatadditional stores could be carried underwing

and the aircraft's configuration meant that a

certain amount of nose-down attitude was

required for bomb release.

Although the P.08.01 was an interesting

design, it was over-ambitious and appears tohave progressed little further than the initial

design phase. A later series of Messerschmitt

studies for an advanced high-speed jet pow

ered bomber was undertaken toward the

end of the war in an attempt to meet evolvingRLM needs. This project generated a number

of widely differing concepts that included

several taill ss designs.

The taille s proposals are said to have been

innuenced by earlier Lippisch designs,

although Lippisch and most of his colleagueshad departed from Messerschmilt some time

before this project started. Messerschmilt

designers, Siefert and Konrad, are credited for

these designs. Initially assigned the reference

P.II07, the study followed two different lineof development. The first was a fairly conven

tional four-engine tailed aircraft and the sec

ond was a semi-delta shaped tailless design.

nfortunately, there is very little documenta

tion available for the P.II 07 project and the

available details are often velY confu ing.

The RLM required an aircraft capable of carrying an 8,8181b (4,000kg) payload with a

maximum speed of about 600mph (965kph)

and a range of approximately 4,350 miles

(7,OOOkm). It would be powered by Heinkel

Airborne defence role

Free fall bomb

Armament

Crew

Wingspan

Wing areaLength

Height

Gro weight

Maximum peed

Maximum range

Maritime role

tively little documentation has survived,

although in the case of the P.08.01 study, this

can be dated to September 1941 and was pro

duced by Dr Hermann Wurster, apparentlywith some assistance from Dr Lippisch.

The P.08.0 I was a large nying wing powered

by four Daimler Benz DB615 piston engines

driving pusher propellers. It had almost the

same wingspan a a modem orthrop B-2Astealth bomber and Wurster envisaged the

P.08.01 being used in a wide range of different

roles. As a long-rang bomber, the P.08.01

would be capable of crossing the Atlantic and

as a shorter-range tactical bomber it wouldcarry a very substantial bomb load. It would be

adaptable to the reconnaissance role, a trans

port aircraft capable of carrying a small tank

and a rather unusual airbome anti-aircraft plat

form equipped with four 88mm anti-aircraft

guns. P.08.0 I would have also been capable ofundertaking maritime, glider towing duties

and perhaps launching air-to-surface missiles.

Built almost entirely from metal, the wing

featured two different sweep angles and it

has been sugge ted that the P.08.01 might

have been capable of surviving encounters

with barrage balloon cables. Intakes for eachengine radiator would be located in the inner

wing section's leading edge and most of the

aircraft's fuel was carried in this location, with

tanks and engines being heavily armoured.

P.08.0J was fitted with a single tailfin and

utilised split naps. The pressurised cockpit

protruded slightly ahead of the wing andwould have provided good forward visibility.

A substantial, fully retractable tricycle under

carriage supported the aircraft on the ground

and there was a large centrally positioned

257Ft 6in (175m)

26° (leading edge)

592Ft' (55m')25Ft (7.62m)

15Ft 6in (4.73m)

15,3221b (6,950kg)

26,7861b (12,150kg)

1,566 miles (2,520kph)426mph (685kph)

41,OOOFt (I2,496m)

2x 12-cylinder DB603, each ratedat 1,725hp (1,287kW) or 2x

Junkers Jumo 213 12-cylinder

piston engines, each rated at

2,020hp (I ,508kW), during take

off, using MW50 injection.4x 20mm MG 151/20 cannon

mounted in the no e, plus

2x30mm Mkl03 cannon in the

wing roots. Aremote controlled

20mm MG 151/20 cannon in a tail

barbette. An internal bomb load of2,2051b (I,OOOkg) and a imilar

weight in external undef\\~ng tore .

The Messerschmitt P.08.01 long-range bomber,designed by Dr Hermann Wurster, with someinput from Alexander Lippisch.Bill Rose Collection

Armament

Flying Wing Bombers

Messerschmitt undertook a number of stud

ies for long range and heavy bombers during

World War 2 and several of these were nying

wing designs that are often credited to Lip

pisch's Department L. Unfortunately, rela-

Messerschmitt Me 329

and according to one report, a prototype was

completed by early 1945 and test nown at the

R chlin Test Centre before hostilitie ceased.

Crew

Wingspan

weep

Wing area

LengthHeight

Empty weight

Gro weight

RangeMaximum speed

Ceiling

Powerplant


I

~

A twin-engine version of Boeing's Model 306fighter study from 1935. The Model 306C designwas to be powered by two RangerV-770SG V-12engines, each rated at 420hp (313kW).Bill Rose Collection

the design had been taken any further. TheBoeing Model 306C was a twin-engine version of the aircraft powered by two RangerV-nOSG V-12 engines, each rated at 420hp(313kW), located at the trailing edg and driving three-blade propellers. The wingspan ofthe Model 306C was reduced to 38ft (I 1.5m)and the overall length was 22ft 2in (6.75m).Other details such as armament, cockpitposition and control surfaces were virtuallythe same as found on the single enginedesign. Needless to say, the Model 306 seriesof designs progressed no further andremained almost unknown until relativelyrecently.

A 1935 Boeing tailless fighter concept producedduring the Model 306 study and identified as Model306B. Powered by a single Allison V-171 0 V-12piston engine, this aircraft used Boeing's externallypositioned control surfaces. Bill Rose Collection

~~~~0\==~~~(; " (;LJ u L)

speed is unknown, but will not have madethis aircraft a class leader. The Model 306Bhad a project wingspan of 40ft (I2m) and alength of 23ft (7m). Armament comprised oftwo .50 cal (12.7mm) machine guns mountedin the nose and possibly one larger cannon.A fully retractable undercarriage was plannedand the position of the cockpit would haveprovided good visibility. Flight control tookthe form of Boeing's displaced elevon systemand wingtip stabilising fins were planned,probably equipped with rudders.

Whether the idea of a contra-rotating propeller unit was considered is unknown,although this might have proved desirable if

I306B 40ft (12m)306C: 38ft (115m)306B: 23ft (7m)306C: 22ft 2in (675m)UnknownUnknown306B: I xAllison V-17l 0V-12 piston engine rated at850hp (633kW)306C: 2x Ranger V-770SGV-12 engines, each rated at420hp (313kW)Unknown306B: 15,OOOft+ (4,572m+)Unknown306B: 3hoursOne or two .50 cal (l27mm)machine guns mounted in thenose and possibly one largercalibre cannon

Maximum speedCeilingRangeEnduranceArmament

HeightGross weightPowerplant

Boeing Model 306B/C fighter

The second design was for an airliner/transporter with a capacity to carry 28 passengers. Assigned the study reference Model306A, the airliner had a shorter wingspan of106ft (32.3m) and was to be powered byfour Pratt & Whitney SI EG Hornet radialengines, each rated at 750hp (559kW) andmounted in an unusual push-pull configuration. Initial estimates suggested that the aircraft would be able to cruise at 200mph(321 kph) with a range of 1,200 miles(1,931 km). Looking quite advanced for itstime, the airliner featured a fixed tricycleundercarriage and a flush cockpit in the nose,providing excellent visibility for the pilot. Theengine layout was an interesting idea, but calculations showed that the front propellerwould disturb its rear counterpart, leading toa 10 per cent loss of power, so the studyended at this point.

The third Model 306 design was for a flyingboat based on the Model 306 flying wingbomber with a similar wing profile andengine layout. Details of this design remainsketchy and obviously unfinished with drawings showing no stabilising floats whichwould have been essential.

The two remaining Model 306 conceptswere for much smaller one-man fighter aircraft. The Model 306B was a tailless fighterdriven by a single three-bladed propeller in apusher configuration and powered by a singleAllison V-1710 V-12 piston engine. Performance figures for the Model 306B are somewhat vague with an endurance of3 hours anda ceiling of 15,000ft (4,572m). Maximum

Length

CrewWingspan

10140ft (42.6m)60ft (l8.2m)Unknown4xAllison V-I7l0 12-cylinderliquid·cooled piston engine, eachproducing 850hp (633kW)Unknown5,000 miles (8,OOOkm)UnknownUnknown2,500lb (1,133kg) bomb load.2x .50 cal (12.7mm) machine guns,2x .30 cal (7.62mm) machine guns

Boeing Model 306 Bomber

CrewWingspanLengthHeightPowerplant

Gross weightRangeMaximum speedCeilingArmamentDefensive armament

bomber, there was a flying boat, an airlinerand two variations of a compact one-manfighter with all receiving the in-houseumbrella designation Model 306. The longrange bomber was completely tailless withswept wings and an unusual system of external elevons supported behind the trailingedge by long struts. Engineers believed thisunusual system would be more efficient thannormal control surfaces as it avoided anyinterference with the wing's aerofoil profile. Italmost goes without saying that the idea waswind tunnel tested.

The Model 306 flying wing bomber was tobe manned by a crew of 10. The wingspanwas provisionally set at 140ft (42.6m) and theaircraft's length was 60ft (18.2m). Propulsiontook the form of four fOlward-mounted propellers, each driven by an Allison V-171 0 12cylinder liquid-cooled engine, producing850hp (633kW). A fully retractable undercarriage was envisaged with the aircraft's rearsection resting on a tail wheel. The bomberwould have a range of 5,000 miles (8,OOOkm)and carry a 2,500 Ib (I, 133kg) bomb load withdefensive armament consisting of two .50 cal(I 2. 7mm) and two .30 cal (7.62mm) machineguns. Had this aircraft progressed towardsproduction, it seems certain that more gunswould have been added. Weights, maximumspeed and ceiling are unknown, but slightlybetter performance than the XB-15 wasundoubtedly anticipated.

lation of this particular bomber programme.Both the XB-15 and XB-16 were judged tohave insufficient performance and by thistime, the smaller four-engine Boeing B-17 Flying Fortress had been selected for production.

Meanwhile, Boeing was engaged in asecret, almost unknown parallel project todevelop a flying wing aircraft which utilisedsome of the XB-15's features. The company isnot generally associated with the early development of flying wing aircraft and their engineers claimed to have no interest in taillessdesigns as they were considered less stableand harder to control than conventional aircraft. Nevertheless, a series of flying wingswere designed during 1935, perhaps in thehope of achieving certain aerodynamicadvantages. As work progressed, a total of fivedifferent concepts emerged for variou roles.

one of these Boeing flying wing studiesprogressed much further than the drawingboard and they remained unknown until relatively recently. Aside from a long-range

~o 0 ~ 0 0~~OUU U\J

Boeing Studies

A research programme undertaken by the USArmy Air Corps Material Division at WrightField, during 1933 determined that a new fastbomber with a maximum speed of 200mph(320kph), a range of 5,000 miles (8,000km)and the ability to carry a 2,5001b (l,133kg)bomb load was technically feasible. BothBoeing and Martin expressed an interest inthis project and design work commenced inearly 1934. This led to contracts being issuedfor the construction of one prototype by eachcontractor which became known as the Boeing XB-15 and the Martin XB-16.

The XB-15 was an advanced conventionalfour-engine all-metal monoplane. It was builtas a single prototype which would eventuallylead to the B-17 and the B-29. The four engine(later six) Martin XB-16 was a slightly lessorthodox design featuring twin tail booms.While the XB-15 was test flown, the XB-16never reached completion due to the cancel-

US Flying Wings (1935-1950)

Chapter Three

Boeing's 1935 Model 306 long-range, 10-manflying wing bomber proposal, featuring anunusual system of external control surfaces.Bill Rose Collection

70 Secret Projects: Flying Wings and Tailless Aircraft US Flying Wings (1935-1950) 71

CONSOL.OATEO AIIlCRMT COAl'C:JP>!I,TION

12288ft (87.7m)78ft (23.7m)12' leading edge237,8001b (I07,864kg)6xPratt &Whitney, 3,000hp(2,237kW) X-Wasp radial pistonengines, each driving a 19ft(5.79m) diameter Curtiss threeblade pusher propeller394mph (634kph)42,000ft (I2,800m)10,000 miles (I6,093km)72,0001b (32,658kg) bomb load.Forward and rear (remotecontrolled) turrets with 37mmcannons. 2xaft turrets using.50 cal (I2.7mm) machine guns

/

OEFE .... SIVEARMAJ.ENT

&-CANNO'/31MM

6_ GUNS CAL.~

Consolidated Aircraft Large Flying WingBomber (1941-1942)

Maximum speedCeilingRangeArmamentDefensive

CrewWingspanLenglhSweepGross weightPowerplant

HEAVY 90MBER FLYINO WlNO

(2,237kW) X-Wasp radial piston engines,each driving a 19ft (5.79m) diameter Curtissthree-blade pusher propeller.

A maximum bomb load of 72,0001b(32,658kg) was viable for a limited range mission and the planned defensive armamentwas substantial with two forward and onerear (remote controlled) turret equipped with37mm cannons and two aft turrets using .50cal (l2.7mm) machine guns. The flyingwing's gross weight was estimated at237,800lb (l07,864kg) with a maximumspeed at 30,000ft (9,144m) of 394mph(634kph) and a service ceiling of 42,000ft(l2,800m). But it is uncertain if the originaltarget range of 10,000 miles (l6,093km), carrying a 10,000 Ib (4,535kg) bomb load for halfthat distance was altogether realistic. Inappearance, the aircraft was very clean, withno stabilising fins or external features of note.The pressurised cockpit protruded some way

these measures proved totally effective,although the replacement engines were continually operating at their design limits, leading to serious overheating problems. By thesummer of 1941, Jack Northrop was considering another engine change to newLycoming six-cylinder units each providing150hp (l12kW), but this never happened asthere were now plans to move forward witha more advanced design.

Towards a Flying Wing Bomber

Top: Consolidated Aircraft's flying wing alternativeto the B-36 heavy bomber designed in the early1940s. Courtesy Robert Bradley

During April 1941, the US Army Air Corpsissued a confidential request to various aircraft contractors for an intercontinentalbomber with a range of 10,000 miles(l6,000km). It had to be capable of cruising at300mph (482kph), achieving a maximum alti-.tude of 40,000ft (l2,192m) and carrying a10,0001b (4,535kg) bomb load. There was awidespread expectation in Washington thatBritain would surrender to the Nazis and theUS required the ability to undertake transAtlantic bombing missions. A number of proposals were submitted by Boeing,Consolidated, North American, Canadian Car& Foundry (CC&F) and Northrop.

Northrop's proposal would be a muchlarger development of the N-I M and duringSeptember 1941, it was officially acknowledged that despite some propulsive difficulties, the Northrop N-IM had performed welland showed considerable promise. Subsequently, the Secretary of War approved further development of the company's flyingwing bomber.

The other aircraft to receive approval fordevelopment was Consolidated's Model 36(which became the B-36) and a contract tobuild two Model 36 prototypes was issuedduring November 1941. The designers at Consolidated also produced an alternative sixengine flying wing bomber which promisedsuperior aerodynamics and better use ofinternal space. This aircraft would have beensubstantial in size and manned by a crew of12. The wingspan was 288ft (87.7m), with a12° leading edge sweep and an overall lengthof 78ft (23.7m). Propulsion was broadly similar to the system chosen for the Model 36,comprising of six Pratt & Whitney, 3,000hp

Right: Some very basic company artwork, showinginternal features of the Consolidated Aircraftsix-engine flying wing proposal.Courtesy Robert Bradley

The method of flight control was similar tothat employed by the Horten Brothers fortheir aircraft with the elevons being adjustedtogether for pitch and differentially for roll.Rudder control was undertaken using splitflaps at the wingtips and could be used toinduce yaw or reduce speed. The aircraft wasalso built to allow modest pre-flight changesto the wing profile during testing. Completedby mid-1940, the Northrop N-IM was giventhe nickname 'Jeep' and trials began atBaker's Dry Lake in California. The test pilotwas Vance Breeze and according to reports,the first test flight occurred accidentally during a high-speed taxi run. However, duringthe tests that followed, the aircraft failed toclimb more than a few feet above the groundand two problems were soon recognised.Firstly the aircraft was underpowered and itwas decided to replace the Lycomingengines with two 117hp (87.24kW) Franklinsix-cylinder, air-cooled units driving threeblade propellers.

There was also an aerodynamic problemwhich was quickly identified by the leadingaerodynamicist Dr Theodore von Karman. Hepinpointed an airflow separation problemcaused by the N-IM's wing and suggestedextending the length of the elevons. Both

designed many tailless aircraft concepts andbuilt small models made from balsa wood inhis spare time. Northrop was convinced thatthe next major advance in aircraft design wasa sleek elegant one-piece wing that did notrequire a tail. By 1937, he was testing windtunnel models of tailless aircraft and when heset up a new company in 1939, there was thefinance, staff and facilities required to pursueflying wing development.

During the summer of 1939, work began onthe construction of a small propeller drivenflying wing called the N-IM (NX-283 I I) whichhad a wingspan of 38ft (l1.58m), a length of17ft (5.18m) and an empty weight of 4,000 Ib(I ,814kg). Jack Northrop envisaged the N-l Mas a one-third sized proof-of-concept demonstrator for a larger commercial or military aircraft. The distinctive yellow coloured N-I Mwas mainly constructed from wood, withmetal only being used when necessary. It wasinitially powered by two 65hp (48.7kW)Lycoming 0-145 four-cylinder piston enginesdriving two blade pusher propellers. Becauseof this propulsive system, a fully retractabletricycle undercarriage was necessary and asmall tailwheel in a fairing was added as asafety measure to ensure that any accidentalrollback on the ground was limited.

Right: Jack Northrop (left) talks to the pilot of theexperimental N-1 M flying wing prototype duringtests at Baker's Dry Lake, California, in 1940.Northrop Grumman

Above right: The Northrop N-1M proof-of-conceptdemonstrator with its dihedral wingtips in raisedposition. Northrop Grumman

Above: John 'Jack' Knudsen Northrop.Northrop Grumman

Jack Northrop

One man totally dominated US military flyingwing development during much of the 20thcentury and he was John 'Jack' KnudsenNorthrop (1895-1981). The Northrop familymoved from Newark, New Jersey, to Santa Barbara, California, in 1914 and Jack Northropjoined the Loughead Brothers aviation business (later becoming Lockheed). After severalyears with the company, Northrop became itschief engineer and much of his time wasdevoted to working on Curtiss flying boats.Soon after World War I ended, the aviationbusiness slumped and Loughead had closedfor business by 1921. Jack Northrop worked asa garage mechanic until 1923 when he finallymanaged to secure a job with the newly established Douglas Aircraft Company at Santa Monica, California. In 1927, he left Douglas to brieflywork with his former colleagues at Lockheedand most of this period was spent designingthe Vega. Then in 1928, Jack Northrop formedthe Avion Company with Kenneth Jay andfinally set up Northrop Aviation with help fromDonald Douglas of Douglas Aircraft.

Jack Northrop had been interested in theidea of building flying wing aircraft since hisearliest days in the aviation business. He had


Armament

amount of teeI tubing. It was also equippedwith a similar fully retracting tricycle undercarriage and a retractable fourth wheel tohelp protect the propellers during take-offsand landings. Cockpit space was tight, due tothe carriage of special test equipment. Likethe -1M, the normal control stick wasreplaced with a column and wheel to mimicthe proposed larger bomber. However, vi ibility from the cockpit was very good, due toits forward position and the use of a bubblcanopy.

nusually, no civil or military registrationswere assigned to any of the orthrop -9Maircraft. -9M-I first fiew on 27 December1941 and subsequent nights were plaguedwith m chanical problems, usually attributedto the Menasco engines. The prototype p rformed quite well delivering a ma'Ximumspeed of about 250mph (400kph), a ceilingslightly b tter than 21,000ft (6,400m) and arange of about 500 mil s (800km).

nfortunately for Northrop, trials began tofall behind schedule due to ongoing techni alproblem and limited information was gathered on the aircraft's stability and drag characteristics. Then on 19 May 1943, after just22.5 hours of accumulated fiying, -9M-1piloted by Max Constant crashed about 12mil s (20km) west of Muroc Field. The

-9M-1 had entered a violent 60° nose-downspin and Constant tried every mean torecover the aircraft. The small left hand antispin parachute had been released and thefiaps were partially lowered, but to no avail.Having reali ed he was in serious trouble,Con tant released the cockpit canopy andprepared to bailout, but failed to leave the aircraft and was killed. There were now seriousconcerns about the aircraft's stability and itwas clear that the elevons on the first N-9Mhad undergone a control reversal during thspin. NA A Langley was asked to study ascale model in its spin tunnel to determine ifchanges should be made to the control urfac s and spin chutes.

Th following month, N-9M-2 was completed and it took to the air on 24 June 1943.There were a eries of minor problems resulting from the cockpit canopy detaching duringthis test-night, but the trial was judged a success. Flights continued throughout theremainder of the year and stability and directional control were judged satisfactOly ratherthan outstanding. Good data was bingreturned, although it had become apparentthat drag produced by the full-sized XB-35would be greater than indicated during testswith wind tunnel models. While development work on the full-sized XB-35 continued,Northrop ompleted a third -9M, now d sig-

Northrop Receives Approval

orthrop was now gearing up to develop itsfiying wing strategic bomber and a formal

SAAF contract (W535-AC-2134 I) had beenissued on 22 ovember 1941 to begin work.This covered construction of the first -9Mscale demonstrator, a mock-up of the XB-35,a prototype XB-35 and the option of buildinga second aircraft. Somewhat optimistically,the delivery date for the first XB-35 wasNovember 1943.

Soon after work began on the constructionof a one-third-scale size -9M prototype,Northrop received a second contract (W535ac-33920), which amongst other thingsrequested two further N-9M aircraft. All threeof these prototypes now received designations: -9M-I, N-9M-2 and -9M-3. The

orthrop N-9M fiying wing wa intended to bea one-man aircraft, although it could bereconfigured to accommodate an observer ifthe 41.5gal (I 89 litre) fuel tank located behindthe pilot was removed. The -9M had awingspan of 60ft (I 8.3m), a length of 17ft 9in(5.4m) and the first aircraft weighed 6,3261b(3,175kg) fully loaded. Two Mena co C6S-4piston engines powered the -9M, each ratedat 275hp (205kW) and driving two-bladedpusher propellers. Like the earlier -I M, theN-9M was built using similar methods andmaterials that were primarily wood, withsome aluminium components and a certain

with a maximum capacity of 72,000 lb. Flownby a crew of 12, the B-2000B would be fittedwith seven gun turrets, mainly located in thetail booms. Burnelli also worked on a commercial airliner based on thi design whichwould be capable of carrying 100 passengerfrom London to ew York.

An alternative concept for the new SAAFbomber was Burnelli's B-IOOO. Oftendescribed as a fiying wing, the B-IOOO didn'treally meet the terms associated with thistype of aircraft and is more correctlydescribed as a lifting body. This design wouldhave used a substantial, but shorter tailplaneunit mounted above an extension of the central trailing edge and supported by threeupright fins. Other details appear similar tothe B-2000B such as the propulsion layoutand cockpit location. Wing pan is understood to have been 220ft (67m) with an overall length of 80ft (24.3m). By the start of 1942,the Burnelli bomber had been rejected fortechnical reasons, although it has since beenclaimed that this aircraft was the victim of apolitical conspiracy, possibly involving Pre ident Roosevelt.

ahead of the wing, affording good vi ibilityand it was connected to a crew compartmentat the rear via an access tunnel. The aircraftwas equipped with a fully retractable tricycleundercarriage omprising of a single 65in(1.64m) diameter no e wheel and 80in (2m)diameter twin-wheel sets at the rear.

The company reference for thi designremains unclear and the small amount ofdocumentation available will typically ju trefer to the project as the Six-Engine, LongRange, Flying Wing Bombardment Airplane.It remains uncertain exactly when this alternative study was initiated, but available company documents suggest that work involvingscale models and wind tunnel testing continued into 1942 before the project was shelved.

The CC&F submission for a long-rangebomber wa conceived by Vincent JustuBurnelli and although unsuccessful it remainsan interesting design. Burnelli had b enresponsible for a number of unorthodox aircraft, often utilising lifting body features, withthe emphasis on afety and load carrying efficiency. In the late 1920 ,he worked on a largetailless fiying wing design which was filed asa S Patent on 23 February 1933 and published two years later (Patent 1987050). Thismulti-engine concept was quite advanced forits time, making good use of internal spaceand utilising a fully retractable four-wheelundercarriage. Wingtip stabilisers and rudders were planned, although Burnelli seemsto have overlooked the issue of cockpit visibility in his qu st to produce a clean design.

evertheles , the design was impre sive forit time.

As a submission for the 1941 US long-rangebomber proposal, CC&F produced plans andspecifications for a large lifting body aircraftcalled the B-2000B. Based on various earlierdesigns, the B-2000B was essentially a development of Burnelli's 1933 fiying wing fittedwith two fairly substantial booms and atailplane. The other major revision was acockpit section that protruded forward fromthe straight central leading edge. Propulsiontook th form of four forward-mounted contra-rotating propeller units, driven by eightunspecified piston engines. Some documentation indicates an alternative layout using sixcontra-rotating propeller units, each driven bya liquid-cooled Allison V-3420 engine (builtfrom two Allison V-I710 engines using thesame prop shaft) providing a total of 12,600hp(9,395kW) continuous output and a maximum speed of about 300mph (482kph). TheB-2000B had a proposed wingspan of 220ft(67m), a length of 126ft (38.4m) and an estimated gross weight of 220,000 Ib (99,790kg).The range was dependant on the bomb load

12220ft (67m)6,5 Oft' (611m2

)

126ft (38.4m)110,0001b (49,895kg)220,000 Ib (99,790kg)Several proposal, utilising six oreight unspecified piston enginedriving forward-mountedcontra-rotating propeller unitBomb load 72,000 Ib (32,658kg).7defensive machine gun positions

Maximum speed 300mph (482kph)Range (max bomb load) 2,000 miles (3,21 km)

Burnelli B-2000B

CrewWing panWing areaLengthEmpty weightGross weightPowerplant

The Burnelli UB-14B lifting fuselage, light transportaircraft (X-15320) constructed in 1935-36. It wasalmost identical to the earlier UB-14 (X-14740) thatcrashed during its test flight on 13 January 1935 at

ewark, New Jersey, following detachment of bothailerons. Aspects of pre-war designs like this UB-14Bwould be used in the design of a wartime lifting bodybomber proposed to the USMF. Burnelti Aircraft Lid

This artwork shows the Burnelli B-1 OOOB which was one of several submissionsby Canadian Car & Foundry for the USMF's long-range bomber proposal of194 I. Although not true flying wings, the Burnelli bomber designs offered anumber of technical advantages over more conventional designs, but failed towin official support, possibly for political reasons. Bill Rose Collection

An airc.raft based on the wartime Burnelli B-2000 proposal for a bomber. It istaken from S Patent Design 160842 which was filed in 1949. S Patent Office

This drawing is based on US Patent Design 136249 filed on 7 October 1942.o details of this Burnelli four-engine lifting body aircraft have been located,

but it appears to be part of the wartime bomber study. US Patent Office

74 Secret Projects: Flying Wings and Tailless Aircraft US Flying Wings (1935-/950) 75

Northrop N-IM

CrewWingspanLengthHeightEmpty weightPowerplant

Northrop N-9M

Crew

LengthWingspanHeightWing areaEmpty weightGross weightPowerplant N-9M

Powerplant -9M-B

Maximum speedRange5eIVice ceilingEndurance

I38ft (l1.58m)17ft (5 18m)5ft (1.52m)4,000 Ib (I ,814kg)2x65hp (487kW) Lycoming 0-145four-cylinder piston engines, laterreplaced by 117hp (8724kW)Franklin six-cylinder, air-cooledengines

I (The N-9M-1 N-9M-B were alsocapable of carrying an obselVer,achieved by removal of a fuel tanklocated behind the pilot)17ft 9in (SAm)60ft (l8.3m)6ft 7in (2m)490ft' (45.5m')5,8931b (2,673kg)6,3261b (3,1 75kg)2xMenasco C65-4 piston engines,each rated at 275hp (205kW)2xFranklin 0-540-7 piston engines,each rated at 300hp (223kW)258mph (415kph)500 miles (805km)21 ,500ft (6,555m)3.2 hours

nated N-9M-A and it was decided to built afourth N-9M aircraft to replace -9M-I whichwould be known as N-9M-B.

-9M-A was passed to the USAAF andmade its acceptance flight on 28 June 1944.This aircraft incorporated numerous designchanges making its handling much closer tothat of the full-sized XB-35. It was equippedwith split trailing edge and pitch control flaps,plus leading edge slots to reduce the possibility of stall at high angles of attack. Trials continued with the aircraft throughout theremainder of 1944 producing consistentresults while the N-9M-B had soon been completed. This fourth and final prototype wasequipped with more powerful 300hp(223kW) Franklin 0-540-7 supercharged 8cylinder piston engines, driving two-bladeHamilton Standard propellers in a pusherconfiguration via shafts and fluid couplers.Further minor modifications had been madeto this fourth prototype and like the originalN-9M-1 this aircraft could be adapted to carryan observer by removal of a fuel tank. Oncecompleted, the fourth N-9M was also passedto the USAAF for testing.

Development of the XB-35 was taking farlonger than expected, largely due to a shortage of qualified engineers and skilled staff,but flights of the thre smaller prototypes continued until the end of World War 2. TheseNorthrop flying wings were never intended tobe anything more than research aircraft that

Left: The Northrop N-9M 1 during a test flight inearly 1943. 'orthrop Grumman

Boltom: Wreckage of the Northrop N-9M-1 whichcrashed on 19 May 1943 about 12nm (20km) westof Muroc Field. USAF

would demonstrate the viability of a largermilitary d sign. But it is clear from examination of patents and documentation thatNorthrop considered several slightly largeraircraft based on the N-9M such as a twinengine light-bomber.

The original N-I M ended up with theational Air & Space Museum in 1949 and

after everal decades in storage was returnedto its original condition. The -9M-B found itsway to the Chino Planes of Fame Museum inCalifornia where it was restored to flying condition. The other two N-9Ms were broken upfor scrap.

The XB-35With work underway on the XB-35 programme, Northrop received a contract tobuild an additional 13 pre-production aircraft.These would be designated YB-35 and thedetails were formalised on 17 December1942. Furthermore, a decision had beentaken to request the construction of 200 B-35bombers to follow these test examples andthis became the subject of a contract issuedin June 1943. But it was already apparent thatdevelopment of the B-35 would take longerthan anticipated and completion of the firstproduction aircraft was rescheduled tomid-1945. Having secured a substantial orderfor the new bomber, Jack Northrop began tolook for additional manufacturing capacityand approached the Glenn L. Martin Company. This led to a general agreement thatNorthrop would produce the prototypes andpre-production aircraft, while Martin wouldtake responsibility for building the productionmodels at its Baltimore, Malyland, facility.

The XB-35's wingspan was 172ft (52.2m)with a tapering chord and a leading edgesweep of 27". The wing area was 4,000ft' (370m'), the height was 20ft 3in (6.2m) and theoverall length was 53ft I in (l6.2m). It is interesting to note that the modern Northrop B-2Astealth bomber has the same wingspan, marginally less height and is approximately 13ft(3.96m) longer due to the B-2A's unusualwing profile with its 35° leading edge sweep.However, whereas the modern Northropbomber would normally be flown by twocrew members with the option of a third, theB-35 was designed from the outset to accommodate at least nine personnel (and possiblymore). These would consist of the pilot and

co-pilot, a navigator, engineer and radio operator, plus a bomb aimer and three gunners.To make long missions more acceptable,there would be six folding bunk bed anda small galley. The pilot was located in aforward cockpit that was slightly offset fromcentre and covered by a bubble canopy.The co-pilot was located in a lower glazedsection next to the bomb aimer with thenavigator and engineer behind them. Likethe earlier small Northrop prototype flyingwings, the full-sized aircraft was supportedon the ground by a retractable tricycleundercarriage.

Propulsion for the new orthrop bomberwas to be provided by four substantial Pratt &Whitney Wasp Major supercharged aircooled radial engines. Two of the engineswere R-4360-17s and two were R-4360-2Is. Inactual fact, all the engines for this aircraftwere identical and the only difference wasthe length of their extension shafts. Development of the R-4360 started just before theXB-35 programme and it was a very complexpiece of engineering: a 28-cylinder, four-rowradial engine with each row slightly offset.Although generally reliable, the engine hasbeen described as a maintenance nightmare.This large unit utilised a complex carburettorand turbo-supercharger system. Each aluminium-alloy cylinder head was equippedwith two manually adjusted valves per cylinder operated by push rods and there were atotal of 56 spark plugs linked to four BendixScintilla S14RN-15 low-tension dual magnetos. Early trials indicated that each enginewould provide 3,000hp (2,237kW) with thepossibility of higher performance as development progressed. It was decided to placecooling slots for the engines in the leadingedge of the wing and each engine would becoupled to a rear-mounted contra-rotatingfour-blade propeller beyond the trailingedge. The engines were capable of operatingat an altitude of 40,000ft (12, 192m) and providing a maximum speed of about 390mph(627kph). With a take-off weight of 209,000 Ib(94,800kg), the aircraft was expected tohave a range of just over 8,000 miles(12,874km).

While the range of the B-35 was less thanoriginally contemplated by the USAF, the general performance was significantly betterthan early versions of the Boeing B-29, which

This photograph taken in 1946 shows an X-35 wingsection during assembly at Northrop's Hawthornefacility in California. USAF

The first XB-35 prototype (42-13603) is rolled outat Northrop's California plant in early 1946.

orthrop Grumman

had set the benchmark for bombers of thisperiod. The Northrop flying wing would bebuilt almost entirely from metal using substantial amounts of a new aluminium alloydeveloped by Alcola. Fuel was carried in aseries of self-sealing wing tanks with provision for extra tank installation within the wingand bomb bays allowing extended rangemissions. Double split flaps on the outer trailing edge provided lateral control or brakingwith substantial elevons for control of pitchand roll.

A number of defensive remote-controlledgun turrets were planned for the B-35. Thesewould all be fitted with 0.50in (l2.7mm)machine guns. The remote turrets would bemounted above and below the rear tailcone

and in four units above and below the wing,outboard of the engines. The gunners wouldcontrol and operate their weapons fromwithin several stations covered with transparent domes. The aircraft was equipped withno less than eight separate bomb bays andthe proposed bomb load was 16,0001b(7,257kg). The design was structured aroundthe central crew cabin and this rather unsatisfactory layout would eventually become amajor issue for the USAAF as the type ofweapons carried by heavy bombers underwent a dramatic change.

Development of the B-35 progressed at aslow pace with tests of the -9M research aircraft continuing to indicate that performanceof the full-sized flying wing bomber would be


Northrop XB-35 (213603) photographed during atest flight. Northrop Grumman

An air-ta-air study of XB-35 (213603)_Northrop Grumman

Northrop and USAF test pilots jointly undertook an extensive test programme with thefirst aircraft completing about 270 hours of f1ying and the second aircraft about 60 hours.The YB-49 was a decided improvement overthe propeller-driven aircraft, although it stilldisplayed stability problems. During tests, themaximum speed was established at 520mph(836kph) and the ceiling set at 42,000ft(l2,80Im), although slightly higher altitudeswere achieved. On 26 April 1948, the firstYB-49 set a new unofficial record by making anine-hour flight, of which six hours werespent above 40,000ft (12, 192m). But the rangewas considerably less than the piston-engineaircraft, allowing a distance of approximately4,000 miles (6,437km) with a 10,000 Ib(4,536kg) bomb load. The crew requirementfor the new aircraft had fallen to seven, butthere was the option of accommodating areplacement crew in the tail section of the aircraft for a long duration mission.

While the aircraft were performing quitewell during these trials, stability remained amajor issue and Lt Gen Benjamin W. Chidlaw, who was Deputy Commander of the AirMateriel Command, decided that this problem should receive top priority. Compared tothe Boeing B-29, the YB-49 (when flown without autopilot) performed very badly as abomber with the flying wing producing twicethe B-29's circular average error during simulated missions. The B-29 would usually attainstability during a bomb run in 45 secondswhereas the YB-49 never managed a bettertime than four minutes. Despite having anautopilot, it was generally thought that the

The Northrop 8-49In 1944, Northrop undertook a study to determine if the B-35 flying wing bomber could bedeveloped into a jet-powered aircraft. Thisled to a change in the USAAF's contract withNorthrop during the following year thatallowed the future conversion of two YB-35sto a new configuration using six or eight turbojets. But it was clear that a jet-powered version required additional fins to replace theyaw dampening effect provided by the propshaft covers and the conversion wouldinvolve a fair amount of work.

Adaptation of the two YB-35s was soonunderway and it had been decided to fit eightrather than six Allison J35-A15 turbojets, eachrated at 4,0001b (l7.8kN) static thrust. Theleading edge was modified to allow the positioning of low-drag air intakes for eachengine, four sets of fins were attached to thetrailing edge and wing fences were positioned on each side of the engine installations. In addition, most of the aircraft'sdefensive armament was removed, leavingjust one remote-controlled tail barbette in thetail.

Although initially designated as YB-35B,these two prototypes were now renamedYB-49. The first YB-49 (42-102367) was completed at Hawthome in the summer of 1947and flown to Muroc by Max Stanley on 21October 1947. Unlike the maiden flight of theXB-35, this mission took place without anydifficulties. The second YB-49 (42-102368)was completed by the end of the year andmade its first relatively trouble-free flight on13 January 1948.

Northrop XB-35 above an unspecified dry lake.The propellers have been changed to singlerotation units following problems with thecontra-rotating units. USAF

Further revisions to the project followed withtwo additional YB-35 aircraft being added asreplacements for the jet versions_ Various different modifications were made to the otherflying wings leading to them being redesignated YB-35A.

The first XB-35 (42-13603) was ready toundertake its first test-flight from Northrop'sairfield at Hawthome, Califomia, to MurocAAF on 25 June 1946. The company's chieftest pilot Max R. Stanley flew the aircraft andflight engineer Dale Shroeder accompaniedhim. Soon after take-off there were enginerelated problems which would reoccur during subsequent trials. This finally broughttesting to a halt on II September 1946 after 19flights. Work continued on the second XB-35prototype (42-38323) and it took to the air on26 June 1947, but similar difficulties wereencountered and the aircraft was groundedafter eight flights.

Problems with the complex gearboxesoperating the contra-rotating propeller unitscould not be resolved and it was decided toreplace the entire assemblies with singlerotation propellers. Flight testing finallyresumed on 12 February 1948 and continuedfor two months, but the substitution of thesecomponents had created unacceptablevibration issues and the aircraft's performance had worsened. Flight stabilityremained unsatisfactory and there weremajor concems about the complexity andreliability of the powerful Pratt & Whitneyengines and their elaborate exhaust systems.

By now, the first YB-35A (42-102366) hadbeen completed and was fitted with singlerotation propellers, while efforts continued todeal with the vibration problem. This aircraftwas equipped with defensive weapons andmade its first test flight on 15 May 1948. Various proposals followed to use the flying wingsas in-flight refuelling aircraft and to test thefinal YB-35 with Turbodyne XT-37 turbopropengines. This adaptation was provisionallyknown as EB-35B and Northrop installed theengines, but the variant was never completed. Other options for use as a reconnaissance aircraft were considered, but thepropeller-driven flying wing was too unstableto function reliably as a camera platform. Thefirst YB-35 became the only pre-productionpropeller driven aircraft from this series to flyand it was already clear that the days of usingthis method of propulsion for warplanes wasdrawing to a close.

9- pilot, co-pilot, bombardier,navigator, engineer, radio operatorand three gunners53ft lin (I6.2m)172ft (52.2m)27" (leading edge)4,000ft' (370m')45Ib/ft' (220kglm')20ft3in (6.2m)9ft 6in (2.9m)120,0001b (54,432kg)180,000 Ib (82,000kg)209,0001b (95,000kg)4xPrall &Whitney R-4360supercharged air-cooled radialengines, each rated at3,000hp(2,200kW). Initially driving contraprops, later single rotationpropellers391 mph (629km/h)8,150 miles (I 3, IOOkm)39,700ft (12,100m)625fVmin (I90m/min)20 x.50 (12.7mm) M2 machineguns.16,0001b (7,257kg)Bomb load

Maximum speedEstimated rangeService ceilingRate of climbArmament

LengthWingspanSweepWing areaWing loadingHeightFuselage diameterEmpty weightLoaded weightMax take-off weightPowerplant

Crew

Northrop YB-35

An underside view of the Northrop XB-35 equippedwith the troublesome contra-rotating propellerunits. Northrop Grumman

less than predicted. In addition, Martin wasexperiencing staff shortages due to the wareffort which meant that initial deliveries of theproduction aircraft could not be guaranteedbefore 1947. By spring 1944, these issueswere starting to generate concems within thePentagon and a decision was taken on 24 May1944 to cancel Martin's contract to build theB-35.

However, Air Technical Services Command still wanted the prototype and pre-production aircraft for test purposes and it wasagreed in December 1944 that the projectshould continue. By mid-1945, the war inEurope was over and the USAAF was lookingahead to a time when propeller-driven warplanes would become outdated. Althoughwork was continuing on the XB-35, theUSAAF requested Northrop to adapt two ofthe YB-35 airframes to accept Allison J35-A-5engines. These modified aircraft receivedthe initial designations YB-35B (later YB-49).


an airplane'. On the return to Muroc AFB, Cardenas landed at Wright-Patterson AFB, Ohio,allowing a detailed inspection of the aircraftby USAF specialists. Having left for Muroc AFBon 23 February 1949, there were serious problems with four of the YB-49's jet engines, forcing Cardenas to make an emergency landing

Below: Underside view of the YB-49 in flight.Northrop Grumman

Above: Capt Glenn Edwards, who was killed whenthe second YB-49 (42-102368) crashed during atest flight on 5 June 1948. As a mark of respect,Muroc AFB was renamed as Edwards AFBon 5 December 1949. USAF

AFB (now operated by the Kansas AirNational Guard) in honour of the Kansas-bornpilot on 13 July 1949. This was followed byMuroc AFB being renamed as Edwards AFBon 5 December 1949 in memory of CaptainEdwards, who grew up in California.

Despite this tragic loss, the USAF intendedto press on with the flying wing programmeand the conversion of the YB-35 airframescontinued at Northrop. With only one YB-49available for evaluation, it was decided toextend the test period for this aircraft. TheUSAF also planned to place a fresh order for30 RB-49B aircraft designed for reconnaissance missions. But the technical problemswith the flying wing continued throughout theremainder of the year. Most pilots found theaircraft difficult to fly and there was constanttrouble with the engines.

At the start of 1949, the USAF requested thatthe YB-49 was flown across the US toAndrews AFB so it could participate in a military display attended by senior officials andpoliticians. The YB-49 departed Muroc AFBon 9 February 1949 with USAF pilot MajorRobert Cardenas at the controls. He wasaccompanied by co-pilot Capt W.W. Sellerand Max Stanley acting as an observer and arepresentative of Northrop. When the aircraftarrived at Andrews AFB, it had completed the2,258-mile (3,634krn) non-stop flight in 4hours and 20 minutes, averaging an impressive speed of 511 mph (822kph).

The air show went well with no hitches andPresident Harry S. Truman inspected theYB-49, describing it as looking like 'one hell of

(305mm), which was unacceptable.Whether or not a modified bomb with ashorter length was considered is unknown,but there was no possibility of moving thebomb further forward. These weapons had tobe suspended from within the bays, whichmeant they were partly enclosed and therewere issues of weight distribution.

Nevertheless, the prevailing post-war interest was the carriage of newly developedatomic weapons. The only operational aircraft capable of doing this was the B-29, butthere was the Convair B-36 strategic bomberin development that could carry largeweapons with ease and the future B-47medium bomber would also be nuclearcapable.

The Northrop B-35/B-49 was unable tocarry the newly developed Mk3 'Fat Man' plutonium bomb which would just about fitlengthwise in a bay, but was too wide with its5ft (1.52m) diameter and rather awkward boxtail. With nuclear weapons having to be physically armed by a specialist before release,the bomb had to be accessible to the crew. SoNorthrop engineers carefully examined waysof modifying a bomb bay to accept the Mk3atomic bomb and finally decided that theonly practical answer was to carry theweapon semi-externally, covered by a jeWsonable bathtub-shaped fairing. The problemwas that the cover would have extendedback over the wing flaps and was expected tosignificantly degrade performance. The situation improved slightly when the Mk4 atomicbomb became available in 1949. The weaponcould have been carried within the B-35 orB-49's bomb bay, providing that various modifications were made to the surroundingstructure. But alterations would have beenvery expensive and quite complicated,requiring amongst other things, new speciallyshaped bomb bay doors.

Despite growing concerns about the futureof Northrop's flying wing bomber, the secondYB-49 (42-102368) was passed to the USAF on28 May 1948. A few days later on 5 June 1948,this aircraft crashed just north of Muroc AFB,killing the pilot Daniel Hugh Forbes Jr., his copilot Captain Glenn Edwards and three crewmembers. The aircraft was almost completely destroyed by the impact, although asection of wing was recovered several milesaway. The exact cause of the accident hasnever been fully identified, but it was clearthat a major structural failure occurred. TheYB-49 had entered a dive from 40,000ft(12, 192m) and one eyewitness described theaircraft as tumbling about its lateral axis priorto impact. As a result of this accident, TopekaArmy Airfield, Kansas, was renamed Forbes

Preparation taking place for a test flight of theNorthrop YB-49. USAF

This simulated image shows an underside view ofthe Northrop XB-35 carrying two large groundpenetrating bombs. Although this capability wasstudied in detail, there were serious problemspositioning these weapons and the small amountof clearance between the tail of each weapon andpropeller blades created serious concerns.Bill Rose Collection

The jet-powered version of Northrop's flying wingbomber, designated YB-49. USAF

by Sir Barnes Wallis and used operationallyby the RAF during World War 2 against highvalue German targets. Until the arrival ofnuclear weapons, they remained the onlybombs capable of destroying a hardenedunderground facility and (excluding some trials with a modified B-29) the only post-war USbornber expected to carry them was the massive Consolidated Vultee (later Convair) B-36,which was developed in parallel to theNorthrop flying wing. The B-36 could easilycarry four T-1 Os, three T-14s or two even bigger bombs called the T-12. This was a scaledup T-14 weighing a staggering 43,6001b(19,776kg), which was tested but, like its predecessors, never used by the USAF.

Unfortunately, the B-35's largest bays(inboard) measured 4ft 4in (1.36m) wide, 12ft4in (3.75m) long and 6ft 6in (1.98m) deep. Butdue to the need for adequate clearance, themaximum dimensions of a single bomb hadto be somewhat less than this. These baysremained unchanged for the jet poweredB-49, although the outer bomb bays wereremoved due to changes in propulsion. Thelargest conventional bomb that could be carried by the B-35 weighed 4,0001b (1,814kg)and there was little scope for adaptation tocarry anything bigger as the wing sparsformed the front and rear walls of bothinboard bomb bays. Even carrying the bombsemi-externally was impossible with the T-10having an overall length of21 ft (6.4m) and thebigger T-14 measuring 26ft 6in (8m) includingits tail.

Northrop realised from the outset that itwould be impossible to make any changes tothe aircraft that allowed the internal carriageof longer bombs, so it undertook a study todetermine the possibility of suspending twoT-IO or T-14 bombs beneath bays two andseven. This showed that carriage of thesebombs would seriously degrade the aircraft'sspeed and the added weight of the T-14would reduce the range considerably. Inaddition, the clearance between the tail of a25ft (7.62m) long T-14 and the propellerblades would have been a mere 12in

ering this issue for some time. Clearly therewould be problems with the B-49 because ofits eight separate bomb bays and the size ofexisting free-fall nuclear bombs.

Northrop had been examining adaptationof the B-35 to carry very large bombs sinceearly in 1945 when the USAF began developing plans to use the T-I 0, which was a US-builtversion of the British 12,0001b (5,443kg) Tallboy bomb and the T-14, which was a copy ofthe larger 22,0001b (9,979kg) Grand Slambomb. Both of these weapons were designed

lack of stability with the jet-powered flyingwing was due to the inadequate stabilisingfins. Northrop hoped to resolve this problem,but there were further difficulties for the company when the USAF reviewed the capabilities of the YB-49 and decided to redesignateit as a medium bomber in the same class asthe Boeing XB-47 which was undergoingdevelopment.

Yet another consideration was the aircraft's ability to carry atomic weapons andthe Air Materiel Command had been consid-


The Northrop YB-49 undertaking a test flight fromMuroc MB. USAF

The YRB-49 during a test flight. The reduction inengines from eight to six is clearly visible in thisphotograph. USAF

5- pilot and co-pilot in a tandemcockpit. Two other seats werelocated in the leading edges of thewing roots, and had large windowsfor forward visibility. An additionalposition at the rear of the cabin128ft4in(39.llm)74ft 8in (22.75m)l61,5401b (73,227kg)222,7101b (l01,019kg)(after in-flight refuelling)2xTurbodyne Vturbopropengines, each rated at 1O,000hp(7,457kW) and driving a six·bladed contra-rotating propeller5l7mph (832kph)43,000ft (13, 106m)

2,760 miles (4,44lkm)5,580 miles (8,980km)Two or four machine guns(probably .50ca!) in remotelycontrolled tail turretUnspecified

Crew

Powerplant

Bomb load

WingspanLengthMax ground weightMax flight weight

Northrop 1950 Flying Wing BomberVersion A: Turbodyne V

forward near glazed sections of each innerwing. The aircraft would be equipped withtwo Northrop-developed Turbodyne turboprop engines each producing 1O,000hp

Cruising speedBombing altitudeCombat radius(un-refuelled)(in-flight refuelling)

Armament

cussed in SF literature. As a consequence,Northrop's flying wing bomber had been builtwith a central cabin area and separate bombbays positioned around it. Furthermore, bythe end of the 1940s, physicists were indicating that a significantly more powerful fusionbomb was theoretically possible and assuming it could be built, such a weapon was goingto be very large and the B-36 might be the onlyaircraft capable of carrying it.

Jack Northrop now set about designing anew flying wing aircraft with a large centrallylocated bomb bay that would be able toaccommodate a single 'superbomb'.Northrop was in an excellent position toknow exactly where things were goingwith nuclear weapon design as it was undertaking highly-classified research to improvethe casing for existing free-fall nuclearbombs. By 1950, he was able to present several ideas to the USAF for a long-range strategic nuclear bomber. The first proposal was fora flying wing aircraft with a forward fuselagesection somewhat resembling the BritishAvro Vulcan.

Generally referred to as the Turbodyne V,this design had a wingspan of 128ft 4in(39.1 1m), a length of 74ft 8in (22.75m) and itwas devoid of any upright stabilising fins. Thecrew of five would be housed in forward pressurised sections, with the pilot and co-pilot intandem and two other crew members facing

Scrap metal from one (or more) of the Northropflying wing bombers, dumped at Northrop'sHawthorne Plant. This photograph is believed tohave been taken in 1953. USAF

The YRB-49 with its undercarriage lowered.Northrop Grumman

The remaining YB-49 was destroyed in anaccident while making a fast taxiing run atEdwards AFB on 15 March 1950. It began withthe aircraft's nose wheel strut collapsing andalthough the three-man crew escaped, theaircraft caught fire. But there was no replacement for the YB-49 as the conversion programme had ended some months earlier.The remaining flying wing took to the air on 4May 1950. Designated as the YRB-49A, thisheavily-modified variant with a reconnaissance capability was a significant step awayfrom Jack Northrop's original idea for a clean,aesthetically-pleasing and efficient aircraft.Changes to the propulsion system hadresulted in the engines being reduced to sixAllison J35-A-19 turbojets, each rated at5,0001b (22.24kN) static thrust. However, twoof these engines were housed in pods belowthe wing to allow increased fuel within theaircraft. A crew of six would fly the aircraftwith photographic equipment carried in thetail cone.

After a series of test-flights at Edwards AFB,it was clear that the aircraft could not compete with Boeing's B-47 and the flying wingproject was cancelled. The YRB-49A was thenplaced in storage at Northrop's facility locatedat Ontario International Airport, California,and finally scrapped in November 1953.

The Flying Wing H-BomberAside from stability problems, the majorshortcoming of the B-35 and B-49 was inadequate bomb bay space. The preliminarydesign had been completed at a time whenthe idea of a huge ground-penetrating bombhad yet to be considered and atomicweapons remained ideas occasionally dis-

7172ft (52.42m)4,000ft' (370m')27' (leading edge)53ft (l6.lm)15ft (4.57m)88,4421b (40,116kg)193,9381b (87,968kg)8xAllison J35-A-15 turbojets,each producing 3,750 Ib (l6.68kN)static thrust419mph (674kph)520mph (863kph)42,000ft (I 2,80Im)4,000 miles (6,537km) with a10,000 Ib (4,535kg) bomb load.1,150 miles (I,850km) with a36,7601b (l6,674kg) bomb load4x.50 (l2.7mm) remotelycontrolled M2 machine gunsin tailcone turret

Cruise speedMaximum speedCeilingRange

Armament

Northrop YB-49

CrewWingspanWing areaSweepLengthHeightEmpty weightGross weightPropulsion

The YRB-49A was the final version of the Northropflying wing bomber. The propulsion system wasextensively modified and the aircraft wasreconFtgured for long-range reconnaissanceoperations. The YRB-49A first flew on 4 May 1950,but it was not a success and was finally scrappedbringing this flying wing programme to an end.Northrop Grumman

at Winslow Airport, Arizona. It was soondetermined that the oil tanks for the J35 turbojets had not been filled before departure atWright-Patterson and the FBI was requestedto investigate, although its findings werenever released and the matter was quietlyforgotten.

Things continued to go wrong and on 26April 1949, a serious engine fire caused substantial damage requiring repairs amountingto $19,000, which was a sizable amount inthose days. Trials resumed and continuedthroughout the remainder of that year withemphasis on the ability to deliver bombsaccurately with and without the E-7 autopilot.But the results were still judged unsatisfactoryby most pilots. Official interest in the Northropflying wing continued to diminish and duringNovember 1949, the USAF decided to abandon the conversion of the remaining YB-35sto YB-49s with the exception of one aircraftthat would be adapted for testing in thereconnaissance role.


company report on the project that was completed on 3 December 1943. The primaryobjective was to produce a new type of landbased maritime patrol bomber to replace theConsolidated PB4Y-2 Privateer, which wasdeveloped from the B-24 and had enteredservice with the US Navy in 1943. The Privateer undertook many different duties duringWorld War 2 and the Korean War includingreconnaissance, electronic countermeasures, communication relay, search and rescue, anti-shipping and bombing missions.

The initial flying wing design was occasionally referred to as Model P5Y-l and sometimesa 'Two-Engine Patrol Landplane'. It compriseda wing with a span of 134ft (40.8m) and a fuselage section with an overall length of 52ft(15.8m). Two Pratt & Whitney R-4360 pistonengines in wing-mounted nacelles would provide propulsion, driving rorward-positionedcontra-rotating propellers with eight bladesand a 14ft (4.26m) diameter. The aircraft had aprojected gross weight of 85,000 Ib (38,555kg)and was expected to have a maximum speedof 300mph (483kph), a ceiling of 22,750ft

Convair's Twin-EngineTailless Bomber

When Consolidated and Vultee Aircraft (laterknown as Convair) merged in 1943, the company's engineers at Lindbergh Field, SanDiego, were already working on several newtailless military aircraft. It was hoped thatthese designs would provide better performance and perhaps lower manufacturingcosts than existing aircraft in the same class.Although design work on a flying wing alternative to the B-36 bomber had ended in 1942,wind tunnel tests of the company's two- andfour-engine (tractor configuration) flyingwing models continued at the California Institute of Technology (CaITech).

No details of the four-engine proposalremain and this design appears to have beenabandoned at an early stage. Development ofthe twin-engine flying wing continuedthroughout 1943 with what appears to be afinal set of model tests taking place in CalTech's lOft (3m) wind tunnel from 18-30

ovember 1943. This led very swiftly to a

Consolidated-Vultee's initial wartime proposal for atwin-engine tailless patrol bomber. Robert Bradley

an entirely different league to the XB-49. In1949, a Congressional investigation foundthat there was no favouritism behind thisdecision and Jack Northrop accepted thefindings. But in 1979, an elderly and ratherfrail Jack Northrop participated in an interview conducted by KCET-TV reporter CleteRoberts and told him that undue pressure hadbeen applied by Symington to merge his company with Convair. When he resisted the proposal, Symington scrapped the flying wingprogramme. Northrop added that as a directconsequence, the B-36 went ahead. Whilethere may be an element of truth to some ofthis, it is clear that the decision to drop theNorthrop flying wing was made by USAF specialists who rightly concluded that the aircraftwas unsuitable for their needs.

Certainly the B-36 was far from perfect, butthis aircraft offered superior performance tothe Northrop flying wing and it seemed thatthe less fussy B-47 and propo ed B-52 wouldsatisfy USAF requirements for the next generation of jet bombers. Aside from bomb carriage shortcomings and stability problems,the YB-49 lacked speed and range anddespite some claims, it was never designedto have a low radar cross-section or beregarded as a stealth aircraft.

A version of the B-49 was briefly consideredas a passenger-carrying airliner with the tailcone replaced by a window for a small number of (presumably first class) rear-facing passengers. Northrop built a mock-up of thiscabin section, but there was no serious interest in this proposal from the commercial sector. Several variants of the YB-49 alsoresurfaced during the mid-1950s whenNorthrop answered an official request to submit designs for a bomber that utilised nuclearpropulsion. To protect the rew from radiation, the cockpit area was either located in awingtip pod or at the front of a lengthy forward fuselage exten ion. These particularstudies progressed little further than elementary concepts, although Northrop continuedto work on nuclear-powered bomber designsfor some time.

As a footnote to this section, some stockfootage of a YB-49 in flight was used in the1953 George Pal SF movie War ofthe Worlds.The aircraft is seen flying to drop an atomicbomb on invading Martian forces.

This artwork for an early Consolidated-Vulteetwin-engine tailless patrol bomber design showsthe auxiliary control surfaces in fully-extendedposition. These would normally be retractedduring cruise or high-speed flight. Robert Bradley

Conspiracy Theories?Before the loss of the first YB-49, Northropwas facing stiff competition from Boeing,which was well ahead of the game with itsrelatively sophisticated but more conventional designs. The Boeing B-47 jet bomberhad originated with a USAAF requirementdating back to 1943 and this medium bomberbecame the B-49's main rival. The initialXB-47 had made its first flight in late 1947 anda pre-production batch of 10 B-47As wasdelivered to the USAF for evaluation inDecember 1950. At the same time, Boeingwas developing the larger B-52 that wouldbecome the most successful jet bomber inhistory and will remain in service with theUSAF well into the 21st century.

The Northrop flying wing bomber startedout as an elegant, rather futuristic design, butwas plagued with technical problems. As acompany, Northrop was stretched to the limitduring World War 2 with serious staff shortages and insufficient factory space atHawthorne for XB-35 production. The conversion to turbojet power improved performance, but the aircraft still failed to deliver inseveral respects. It was unable to carry existing atomic weapons and serious stabilityproblems made accurate bomb delivery farfrom satisfactory according to most of the testpilots.

By the late 1940s, Northrop was under pressure from USAF Secretary Stuart Symington tomerge with rival company Convair. The AirForce felt it would be in the best interests ofboth organisations and was a necessaryrequirement for continuation of the flyingwing programme as Northrop lacked adequate production capacity. Jack Northropremained strongly opposed to the idea andsome years later would claim that as a consequence of his objection to this plan Symington brought the flying wing project to an end,awarding Convair a contract for the B-36bomber in its place.

In actuality, the USAF had been far fromhappy with the alternative B-36 strategicbomber and it was never given preferentialtreatment over the Northrop flying wing. TheB-36 experienced reliability problems, lackedperformance and would not have stoodmuch chance against the rapidly improvingSoviet air defences. However, significantimprovements were made to the design thatincreased performance considerably and thebomb delivery capacity of this aircraft was in

perhaps now wary of becoming involved inanother very costly flying wing project whichmight have technical issues that were verydifficult to resolve.

III::>

A remote-control tail turret equipped with.50cal machine guns was located in the tailfor defence purposes. Cruising speed was animpressive 517mph (832mph) with a bombing ceiling of 43,000ft (13,1 06m) and an unrefuelled combat radius estimated to be 2,760miles (4,441 km). With in-flight refuelling, thiscould be increased to at least 5,500 miles(8,850km) and possibly further. The Turbodyne V was somewhat smaller and lighterthan the B-49 with a maximum ground weightof 161,540 Ib (73,227kg) and the efficient turboprop engines and in-flight refuelling capability made it an attractive propositioncompared to the larger jet bomber.

An alternative version of the aircraft, havingthe sam overall dimensions and basic layout, was to be powered by four Allison XT40turboprop engines. Each engine was connected to contra-rotating pusher propellersproducing an estimated total of 30,000hp(22,371 kW). Somewhat heavier, this varianthad a maximum ground weight of 175,400 Ib(79,560kg) and marginally less p rformance.It would be capable of cruising at just over500mph (800kph) and releasing its bombfrom a maximum altitude of 37,000ft(11,277m). The un-refuelled combat radiuswas similar to the twin-engine versionalthough the estimates for longer refuelledflights were not as good. But the designsfailed to make an impression with the USAF,

The Northrop Turbodyne V was a turboproppowered design produced to address the mainshortcomings of the 8-35 and 8-49. It was asignificantly different aircraft, built around a largecentrally-located bomb bay that was judgedadequate to contain a single atomic weapon ofsubstantial size. Furthermore, the range of thisaircraft would be intercontinental with theprovision for in-flight refuelling. However, it cametoo late and by the time this design and severalvariants with different engine layouts weresubmitted to the USAF, the 8-36 and 8-47 wereon order and the 8-52 was in development.Bill Rose Collection

5128ft4in (39 11m)74ft8in (22.75m)175,400 Ib (79,560kg)212, I00 Ib (96,206kg)(after in-flight refuelling)4xAllison XT40 turboprops, eachrated at 7,500hp (5,593kW) andeach driving one six-bladedcontra-rotating propeller unit506mph (814kph)37,000ft (II ,277m)

Bomb load

CrewWingspanLengthMax ground weightMax flight weight

Cruising speedBombing altitudeCombat radius(un-refuelled) 2,761 miles (4,443km)(refuelled at cruising altitude) 4,027 miles (6,480km)

Armament Two or four machine guns(probably .50cal) in remotelycontrolled tail turretUnspecified

Powerplant

Northrop 1950 Flying Wing BomberVersion B: 4 x Turboprop Engines

(7,457kW) and driving six-bladed contrarotating propeller assemblies at the wing'strailing edge. The aircraft would also beequipped with the capability to refuel inflight, allowing long-range missions. Drawings show this aircraft carrying a single bomband it remains unclear if the aircraft wasexpected to have a conventional weaponscapability.


Northrop's Black Bullet

At the end of ]939, Jack Northrop respondedto Army Air Corps request R-40C for a newfighter with superior performance to existingaircraft and significantly lower maintenancerequirements. R-40C also made it clear thatunorthodox designs would receive consideration. Northrop submitted a tailless proposalfor RC-40C which initially carried the company designation N-2B and would competewith rival designs from Bell, Curtiss and Vultee.

The Northrop aircraft was a flying wing witha slightly bulbous fuselage and a contra-rotating propeller assembly at the rear, driven bythe experimental Pratt & Whitney X-] 800-A3G(H-2600) engine located in the centre of theaircraft behind the pilot. The wing profile wassimilar to that used on the N-]M prototypeand there would be upper and lower verticalstabilisers at the rear of the fuselage. An initialUS patent application for this design was filedon 10 May] 940 with a slightly modified version being applied for on 3 December 194],which remained classified until ] 946.

An Army Air Corps development contractfor the Northrop N-2B was issued on 22 June1940 and it was decided to fund the construction of a prototype on 26 September]940. The project had now received thefighter reference P-56 (P for Pursuit was usedprior to F for Fighter) and the prototype wasgiven the registration number 4]-786 andcalled the XP-56. But in October] 940, therewas a serious setback when the Pratt & Whitney X-] 800 engine chosen for the XP-56 failedto meet performance expectations and was

necessary and they had to be kept as far aspossible from the nuclear propulsion system.Consequently, the heavily shielded crewcompartment was located at the centralleading edge with the reactor positioned towardsthe tail.

Specifications are sketchy at best, but thishuge flying wing was to have a wingspan ofapproximately 380ft (J 16m) with an estimated leading edge sweep of 20°. The aircraft's overall length was expected to beabout 89ft (27m), although height isunknown. Two upright stabilising fins werelocated towards the trailing edge and thismassive bomber was supported on theground by a fully retractable tricycle undercarriage. Each main strut was fitted with fourwheels and there were two wheels on the forward strut, although this appears somewhatinadequate. Proposed weights and estimatesfor performance are unknown. The L-248-3would have been specifically designed todeliver free-fall nuclear weapons and perhaps an early hydrogen bomb. NEPA continued until 195] when it became the USAF'sAircraft Nuclear Propulsion (ANP) programme, having determined that the technology was viable. Nevertheless, theLockheed L-248-3 never progressed muchfurther than engineering studies.

As a result of the Nuclear Energy for thePropulsion of Aircraft programme, which began inthe late 1940s, Lockheed's Skunk Worksinvestigated the possibility of building a longrange nuclear-powered bomber. Using Allisonturboprops powered by a nuclear reactor, thissubstantial aircraft was given the design referenceL-248-3. Pete Clukey/Lockheed Martin

stalling speed was slightly increased from85mph (J36kph) to 89mph (143kph). Noticeable changes were a greater wingspan of]47ft (44.8m) and a nominally reduced overall length of 49ft 7in (16m). One other significant change to the design was the addition ofvertical wingtip fins with rudders.

This improved stability and was found toproduce a relatively little extra drag duringwing tunnel testing. The aircraft wasequipped with a substantial tricycle undercarriage and this underwent considerablemodification to simplify its operation. Also,the hydraulic system controlling the undercarriage, brakes and bomb bay doors wasreplaced with an electrical AC system. Yetanother change was the replacement of theeight-blade contra-rotating propellers withslightly larger six-blade versions measuring15ft (4.5m) in diameter. It seems likely thatthe idea of developing this flying wing into abomber for the USAAF was considered, butthe project was finally abandoned in 1944 andthen largely forgotten.

Lockheed's Atomic Bomber

The Lockheed Corporation, based at Burbank Airport, Los Angeles, California, produced artwork depicting a largepassenger-carrying flying wing in ] 938. Utilising six forward-positioned propellers, the aircraft was equipped with substantial wingtipfins and fitted with a fixed tricycle undercarriage. Perhaps influenced by Burnelli andNorthrop designs, it remains hard to say if thispre-war concept was a realistic proposal orsimply created for publicity purposes.

Lockheed does not appear to have takenany interest in flying wing aircraft duringWorld War 2, but this changed in ] 946 whenUS scientists decided that nuclear energymight be suitable for aircraft propulsion andthe Pentagon established a programmecalled Nuclear Energy for the Propulsion ofAircraft (NEPA). Primarily controlled by theUSAAF, the main aim was to develop a newstrategic bomber, perhaps with global range.As an early submission for a nuclear-poweredstrategic bomber to meet NEPA requirement ,Lockheed produced a massive taillessaircraft powered by a hybrid nuclear system.

This Skunk Works design was given the reference L-248-3 and it would be powered byeight highly-modified Allison turbopropengines, each driving a set of forwardmounted contra-rotating propellers. Withenergy provided by a nuclear reactor, thebomber was expected to have a global range.However, this meant that a sizeable crew was

10134ft (40.8m)I,900ft' (176.5m')15' (leading edge)52ft (15.8m)85,0001b (38,555kg)2xPratt &Whitney R-4360 pistonengines, driving forwardpositioned contra-rotatingpropellers with eight blades and adiameter of 14ft (4.26m)300mph (483kph)85mph (I36kph)22,750ft (6,934m)4,770 miles (7,676km) with a10,000 Ib (4,536kg) payload10,000 Ib (4,536kg) bomb load2x20mm cannons in anoseturret,4 x .50cal (l2.7mm) in thetail, three further .50cal gun turrets

Maximum speedStall speedCeilingRange

CrewWingspanWing areaSweepLengthCro sweightPowerplant

ArmamentDefence

(6,934m) and a range of 4, 770 miles (7,676km)with a 10,000 Ib (4,536kg) payload. Flown by acrew of ] 0, the aircraft was expected to carrya substantial amount of defensive armament.This included two 20mm cannons in a noseturret and four .50cal in the tail. Another .50calgun turret was located above and behind thecockpit, with two further retractable gun turrets on the upper and lower rear fuselage. Presumably, withdrawing these units into thefuselage improved the aircraft's aerodynamics. 4,200(US) gal (J 5,898 litres) of fuel wascarried in wing tanks and a second crew compartment was located behind the centrallypositioned bomb bay. Perhaps one of the mostinteresting features of this design was the auxiliary directional and longitudinal control surfaces which would be fully retracted into thewing during cruise and high-speed flight.

By the time a company report on this project was produced in December 1943, thedesign had undergone considerable revision.Gross weight was now increased to 90,000 Ib(40,823kg) and the patrol range had become5,500 miles (8,85] km). The wing area wasreduced from ] ,900ft' (J 76.5m') to ] ,800ft'(J67.2m'), accompanied by a small reductionin leading edge sweep from 15° to ] 4° and the

Consolidated Vultee Twin-Engine TaillessPatrol-Bomber (Initial Version)

Internal layout of the initial Consolidated-Vulteetwin-engine tailless patrol bomber design.Robert Bradley

This artwork based on an original drawing showsthe final design for a twin-engine £lying wing patrolbomber produced by Consolidated Vultee atSan Diego, California, during World War 2.Bill Rose Collection, based on original a.twork

Uetl'actable Irc::otop turret 2_2c.. (Sperry or Emerson)gtLtla, 800 round" amm7 tail turret 4-.50\. od. SWla 4000\. rounds aJlD:I.

/.ulL radar

all 250 gal. total

~&1 1n aelf-a8tl.l1D.« oells

4200 «:&1. total oapaoityL'~""7k:'-- 1,11 wina

Retractable, directional andlongitudinal control surfaces

Two Pratt. WbitneyR-4J60 engines

TWO lJfOIRK PATROL <LUOPlJlBI 'U.ILLltSS T11'ECONSOLlnA'UD VUU'JE AlReRAn' CORPONATlOlfDEVlLOPl6KKT RICIRXEkING, SAN DIPJJO, CAL.

A\18ust 20, 194) ZP-OIO

Retractable SperryBoll turret 2-.50cal. guru!, 800

rounda ammo

Consolidated Vultee's final design for a flyingwing patrol-bomber. Bill Rose Collection

86 Secret Projects: Flying Wings and Tailless Aircraft US Flying Wings (I935-/950) 87

Northrop and this led him to approach theUSAAF with plans for a rocketplane.

Whatever the truth, discussions were soonunderway to develop a prototype rocketpowered fighter. As the country's leadingdesigner of flying wings, Jack Northrop wasthe obvious choice for this project and bySeptember 1942, he had submitted a series ofproposals to the USAAF. This resulted in animmediate contract for three small researchaircraft that would be used in the first stage ofthe programme. The designation MX-365 wasinitially assigned to the project, which thenreceived the experimental fighter referenceXP-79. The first two aircraft in this serieswould be gliders, referred to as MX-334. Thethird aircraft, designated MX-324, would differby having an Aerojet liquid fuel rocket engineinstalled. Security for this undertaking wastight from the outset and it would now beregarded as a top-secret 'black' project,which for all intents and purposes didn't exist.Northrop staff simply referred to the gliders asN-12 and the rocket fighter as N-14.

Having already provided the USAAF withfairly detailed proposals for a rocket fighter,Jack Northrop submitted a complete designin early 1943. His small single-seat flying winginterceptor would be close to a delta shapewith an overall wingspan of 36ft (I 0.97m) anda length of approximately 13ft (3.96m). Thewing's root chord would be II ft 4in (3.45m)with a wingtip chord of 3ft (0.91 m) and wingarea of 255ft' (23.69m'). Skin thickness at theleading edge of the wing was set at 'Xin(l9mm), decreasing to l-ilin (3mm) at the trailing edge. Much of the aircraft would be builtfrom welded magnesium alloy, chosen for its

o

Northrop's Wartime Rocketand Jet Fighters

General arrangement of thesleek Northrop P-79 rocketinterceptor. Bill Rose

By early 1942, British and American Intelligence were aware of German efforts todevelop a high-performance rocket-poweredtailless fighter. The US was interested in duplicating this technology and according to manysources Jack Northrop was approached tobuild an interceptor based on preliminarystudies undertaken at Wright Field. Alternatively, it has been suggested that classifiedinformation was intentionally leaked to

NACA would undertake wind tunnel tests atMoffett Field to investigate the aircraft's poorperformance while flight-testing continued.

But having completed 10 flights, the stability and control problems appeared insolubleand further trials were cancelled. It was nowclear that the days of the piston-engine fighters were coming to an end and the secondXP-56 was stored in a hangar for a year beforethe project was scrapped. From the outsetthis aircraft was doomed to failure and probably should have been abandoned whenPratt & Whitney cancelled its X-I 800 engine.Some other contenders for R-40C were builtand test flown, such as the twin-boom VulteeXP-54 and the canard Curtiss XP-55, but inoverall terms this programme was a dismalfailure with none of the aircraft living up toexpectations.

On 20 December 1946, the XP-56 was transported to the USAAF Storage Depot at ParkRidge, Illinois, and from there it was passed tothe National Air and Space Museum.

I42ft 6in (l2.95m)306ft' (28.44m')37Ib/ft' (l80.6kg/m')1st Prototype: 23ft 6in (7.16m).2nd Prototype: 27ft 6in (8.38m)1st Prototype: 9ft 8in (2.94m).2nd Prototype: II ft (3.35m)8,7001b (3,946kg)11,3501b (5,148kg)12, 145lb (5,508kg)I x Pratt &Whitney R-2800-2918-cylinder air-cooled radial,2,000hp (I ,491kW)465mph (748kph)at 25,000ft (749km/h)417mph (67 Ikph) at sea level33,000ft (l0,058m)660 miles (I,062km)3, 125fVmin (952m/min)at 15,000ft (4,572m)

2x 20mm cannons and4x .50cal (l2.7mm) machine guns

Armament(production model)

Height

Empty weightLoaded weightMax take-off weightPowerplant

Maximum speed

CrewWingspanWing areaWing loadingLength

Service ceilingRangeRate of climb

blew out and the aircraft somersaultedbefore breaking up. The XP-56 was virtually acomplete write-off and photographs indicatethat little could have been salvaged from thewreckage. During the crash, supports holdingthe pilot's seat in place sheared and Myerswas thrown clear of the aircraft, miraculouslyonly suffering minor injuries.

Construction of the second prototype wasnow at a fairly advanced stage and it hadalready undergone a number of modifications. The most noticeable difference was thelarger dorsal fin, accompanied by a change inweight distribution to shift the centre of gravity forward. These changes led to anincreased height of 11ft (3.35m) and a greateroverall length of 27ft 6in (8.38m). Improvements were also made to the wingtip ruddercontrol system using an air-bellows fed bywingtip ducts.

The second XP-56, piloted by Harry Crosby,undertook its maiden flight on 23 March 1944at Roach Lake. The aircraft refused to leavethe ground at speeds below 160mph(257kph), but Crosby finally lifted-off andclimbed to an altitude of 2,500ft (762m) withthe flight lasting eight minutes. On followingflights, it became clear that handlingimproved significantly once the undercarriage was fully retracted, although overall performance proved to be disappointing andwas far less than original estimates suggested. During May 1944, it was decided that

Northrop XP-56 Black Bullet Prototype(Original Estimates)

tungsten inert gas (TIG) welding. The XP-56was equipped with a fully-retractable tricycleundercarriage and a lower ventral fin thatoffered little clearance while the XP-56 wason the ground, but provided some protectionto the rear-mounted propeller blades. Thewing had similarities to N-I M aircraft withelevons at the centre of the trailing edge, flapson the angled wingtips and air intakes forengine cooling ducts at the leading edge wingroots. The wingspan was 42ft 6in (l2.95m)with a wing area of 306ft' (28.44m') and awing loading of 371b/ft' (l80.6kg/m'). Theoverall length of the XP-56 was 23ft 6in(7. 16m), the height was 9ft 8in (2.94m) andtake-off weight was estimated to be 12,1451b(5,508kg). The maximum speed would be417mph (67Ikph) at sea level and 465mph(748kph) at 25,000ft (749km/h) with a ceilingof 33,000ft (I 0,058m) and a range of 660 miles(I,062km). No armament was fitted to theprototype but allowances were made toequip future versions with two 20mm cannons and four .50cal (12.7mm) machine gunsin the nose.

With assembly of the XP-56 prototype progressing well, the USAAF decided to fund theconstruction of another XP-56 and a contractwas issued on 13 February 1942. The secondaircraft was issued with the serial number 4238353. Work on the first prototype was relatively slow and the XP-56 does not appear tohave been given high priority, although it hadnow received the unofficial name 'Black Bullet'. The aircraft was finally completed byNorthrop in April 1943 and transported byroad to Muroc Army Air Base for flight-testing.After a series of taxiing tests at Muroc DryLake, it was found that the aircraft tended toyaw quite badly at high speed. As a consequence, modifications were made to the vertical stabiliser and the wheel braking system.

The first attempt to fly the XP-56 was madeat Muroc Dry Lake on 30 Seplember 1943 withNorthrop's, senior test pilot John WescottMyers at the controls. He managed to brieflylift off the ground at a speed of about 140mph(225kph) but failed to become properly airborne. The flights continued with Myers managing to increase his height from the ground,although the XP-56's performance was disappointing with the aircraft handling badly.Then disaster struck while taxiing at highspeed when the rear tyre on the port side

Anticipated appearance of theNorthrop P-56 flying wing fighter.Bill Rose

Often referred to by the unofficial name 'BlackBullet', Northrop's XP-56 fighter was not a greatsuccess, with the first prototype crashing inSeptember 1943 at Muroc Dry Lake. Thisphotograph shows the second prototype whichcurrently resides at the National Air and SpaceMuseum. Bill Rose Collection

-

extensive alterations to the fuselage werenecessary. As envisaged from the outset, theengine was located just behind the un-pressurised cockpit, driving two sets of threebladed propellers at the rear via a shaft andgearbox. However, the pusher propellerarrangement raised serious issues for thepilot should it become necessary to bail outand Northrop's solution was an explosivecord positioned around the gearbox whichwould be detonated to sever the rear sectionof the fuselage and propeller assembly.

In addition to having an unconventionalshape, the XP-56's airframe was built entirelyfrom lightweight magnesium which wasjoined by a newly perfected process called

abandoned by the manufacturers. The X-1800had been a liquid-cooled 24-cylinder pistonengine with an anticipated performance of1,800-2,200hp (1,342-1 ,640kW) using a turbocharger at higher altitude and there was nosimilarly specified replacement.

In fact, the X-1800's cancellation createddifficulties for all contractors entering theR-40C fighter competition as this engine hadbeen selected for every design. It might havebrought the XP-56 project (and the fightercompetition) to a close, but Jack Northrop'steam decided to replace the X-1800 with aPratt & Whitney R-2800 air-cooled radialengine. Although this was a very capabledesign, it came with a weight penalty and


I32ft (9.8m)244ft' (22.7m')30· (leading edge)12ft (3.7m)3,0001b (I ,360kg)3,6561b (I,658kg)I xAerojet XCAL-200 rocketengine producing 200 Ib thrust(0.88kN)4.20:1300mph (482kph)20 miles (32km) approxNone

Aspect ratioMax speed (MX-324)Range (MX-324)Armament

lems, the aircraft was transported toNorthrop's facility at Hawthorne on I December 1944 for completion.

The redesigned XP-79B was now fitted withtwo engine bays located in the wing roots;each housed a Westinghouse axial flow 19-Bturbojet (an early version of the J30) rated at1,150 Ib (51.kN) static thrust. The gross weightof the XP-79B was 8,6681b (3,931 kg), makingit somewhat lighter than the rocket-powereddesign, but the maximum speed and ceilingwere expected to be marginally less due tothe different method of propulsion and aerodynamic changes. The single vertical finmounted on the rocket-powered XP-79 wasno longer in evidence, having been replaced

MX-334 and MX-324 'Rocket Wing'

CrewWingspanWing areaSweepLengthGross weight (MX-334)

(MX-324)Powerplant (MX-324)

surface of Harper's Dry Lake by the P-38 usedfor these trials. Having left the ground, theP-38 piloted by Martin Smith climbed to analtitude of approximately 8,000ft (2,438m)and Crosby released the towline.

Moments later, he ignited the AerojetXCAL-200 engine and flew under rocketpower for just over four minutes, reaching aspeed of 270mph (435kph) before gliding toland on the lake bed. Crosby had become thefirst American to fly under rocket power,although this event would remain classifiedfor some time to come. Further poweredflights followed, although there were constant difficulties with the rocket engine andthe USAAF was becoming concerned aboutthis troublesome programme. Developmentof the full-sized Aerojet XCALR-2000A-1 liquid-fuelled rocket engine (generally referredto as the Rotajet because of its thrust chamber rotation during operation) was progressing badly and Aerojet Engineering could notguarantee reliability. As a consequence, theUSAAF finally decided to terminate the rocketfighter project. Early concerns about therocket engine had led the USAAF to hedge itsbets in March 1943 with a request that the second XP-79 prototype was modified to accepttwo Westinghouse turbojets. This revisedmodel was designated XP-79B and carriedthe registration 43-52437.

Work eventually started on the XP-79B atAvion, but due to ongoing personnel prob-

Test pilot Harry Crosby flies the MX-324 underrocket power at Harper's Dry Lake in June 1944.Northrop Grumman

One of the few colour images of the NorthropMX-324 at Harper's Dry Lake. Northrop Grumman

although there were complaints about therudder's responsiveness.

Two notable incidents occurred duringthese trials. The first took place when AlexPapana accidentally jettisoned the upper andlower escape hatches of his MX-334 afterrelease from the Lockheed P-38 tow plane.This abrupt change to the aircraft's aerodynamic qualities generated substantial dragand forced him to make an emergency landing. Some days later while flying the secondMX-334, Harry Crosby became caught in thepropwash of the P-38 tow plane and the gliderpitched upwards, stalled and entered a spin.It finally recovered but was now upside downwith Crosby on his back and unable to reachthe controls. Finding himself in a shallowglide, Crosby's only option was to bailout.During his descent, the glider continued tocircle and finally landed on the lakebed, butwas damaged beyond repair.

Glide flights continued at Muroc and byspring 1944, the Aerojet XCAL-200 rocketengine was ready for installation in theMX-324, increasing the gross weight of the aircraft to 3,6561b (I ,658kg) when the fuel tankswere full. The engine with its troublesomedevelopment history had been built at Aerojet Engineering's Azusa facility and was simply known as Project X. Although mainlyfabricated from aluminium, the XCAL-200was relatively heavy at 4271b (I93kg) andwould provide a maximum thrust of 200lb(0.88kN) for several minutes. The engine'sexhaust protruded slightly from the rear of theaircraft, but in other respects the MX-324 wasexternally identical to the gliders. Internallythe aircraft was somewhat different with arevised layout allowing for the engine systemand fuel tanks. To offer the pilot some protection against accidental release of analineor nitric acid (which would be life threatening), thick neoprene screens were installedaround the cockpit.

Now fully equipped, the aircraft was transported to Harper's Dry Lake, Lockhart, California, which was a secret test site in theMojave Desert used by Hughes and Northrop.(Nothing remains of this facility today.)Ground tests began on 29 June 1944 and byearly July, the aircraft was considered readyto undertake its maiden flight. Early on themorning of 5 June 1944, Harry Crosby easedhimself into the cramped cockpit of the fullyfuelled MX-324 and was towed out across the

crossbar fitted with handgrips and use footpedals to adjust the manoeuvring brakes.Production fighters would be fitted with four0.50in (I 2.7mm) calibre M2 machine gunswith provision for 250 rounds per gun. Therewould also be hardened steel panels behindthe inner leading edge and a bullet resistantglass screen at the front of the cockpit. Thepilot's prone position made location of a fullyretractable nose wheel difficult, so it wasdecided to use four separate wheels for theundercarriage.

Part of the contract for this project stipulated that Northrop would sub-contract theengineering and assembly work as there wasa serious shortage of capacity at Northrop'sfactory. This resulted in construction beingpassed to a Los Angeles company calledAvion Inc that had earlier connections to JackNorthrop. Soon after work began on the threeMX prototypes, preparations started for theassembly of three XP-79 prototypes. Twowould be used for flight-testing and the thirdfor stress analysis.

The first three MX aircraft were built frominexpensive welded steel tubing, aluminiumand plywood, but all were similar in appearance to the later XP-79 and accommodatedthe pilot in a prone position. The overallweight of the MX-334 glider was 3,0001b(I ,360kg), making it not much heavier than amedium-sized saloon car. The dimensionsfor the MX-324 and MX-334 were virtually thesame with an overall length of 12ft (3.7m), awingspan of 32ft (9.8m) and a wing area of244ft' (22.7m'). The controls functioned in asimilar manner to the proposed XP-79 withthe pilot accommodated in a prone position.

The first MX-334 was fitted with landingskids, supplemented with a four-wheel takeoff trolley that was jettisoned as the aircraftbecame airborne. This proved unsatisfactoryand it was decided to fit a fixed tricycle undercarriage to the second MX-334 and theMX-324. Fairings were fitted around eachstrut to improve the aerodynamics and it wasnecessary to offset the nose wheel becausethe pilot's prone position within the cockpitprevented adequate central bracing.

John Myers flew the first MX-334 on 2 October 1943 with further trials taking place atMuroc AAF. Other Northrop pilots routinelyinvolved with this programme were HarryCrosby and Alex Papana with a number ofUSAAF pilots also flying the aircraft. All pilotsfelt that the aircraft handed reasonably well,

Testing at NACA Langley in the Full Scale WindTunnel during July 1943. This is described as aNorthrop MX-324 model, but it appears to be theprototype aircraft without undercarriage. NASA

each delivering 1,000 Ib (4.44kN) of thrust andjettisoned once the fighter left the runway.The XP-79 was expected to have a grossweight of I 1,400 Ib (5, I 70kg) allowing a maximum speed of approximately 530mph(850kph) and a ceiling in excess of 45,000ft(I3,716m). Estimates for range or enduranceare unknown although both would have beenshort, restricting this aircraft's role to that of atarget defence interceptor.

It is believed that Jack Northrop and hissenior aerodynamicist Dr William Sears initially favoured a pure flying wing without avertical stabiliser for the XP-79 (plus theMX-334 and MX-324), but reluctantlyaccepted that a fin would be necessary forhigh-speed flight. Directional control of theaircraft was achieved using large elevons andsplit manoeuvring brakes. The pilot wouldcontrol the elevons with a forward-mounted

The experimental MX-324 shown in this drawingwas fitted with an Aerojet rocket engine andreceived the designation MX-324. Bill Rose

low weight and strength. The pilot was contained in a sealed but unpressurised cockpitand would lie in a prone position. Thisallowed Northrop to design a very sleek aircraft and it was believed that this configuration made it easier for the pilot to withstandbrief periods of acceleration, perhaps as highas 12G.

Like the XP-56, this aircraft was alsodesigned around an experimental propulsionsystem that was in the early stages of development and was technically risky. The proposed Aerojet rocket engine for the XP-79would be fuelled with red fuming nitric acidand monoethylaniline (aniline) to provide amaximum thrust ofabout 2,000 Ib (8.89kN). Inaddition, six solid fuel rocket-assisted take-off(RATO) units would be used for a horizontalrunway take-off. They would be attachedbeneath the central rear area of the wing with


Northrop XP-79B: Fighter Prototype

November 1948. During the following month,the aircraft underwent static testing, followedby taxiing trials undertaken by Northrop testpilot Charles Tucker. The aircraft made itsmaiden flight on 16 December 1948 andTucker flew the X-4 for 18 minutes, reachinga maximum speed of 290mph (466kph) andclimbing to an altitude of II ,000ft (3,352m).While Tucker found the handling was good,he also reported a degree of longitudinalinstability. Modifications were made to theaircraft, including the installation of wingtipspin recovery parachutes and changes to theundercarriage. However, winter rains arrivedwhich flooded Rogers Dry Lake and held upfurther trials until April 1949. Flight-testingthen resumed, although there were ongoingreliability problems and Walt Williams whoheaded the NACA Muroc Flight Test Unit(now the Dryden Flight Research Center)described the X-4 as a 'lemon'.

The second X-4 (46-677) had now beendelivered to Muroc and this aircraft hadundergone a number of aerodynamic modifications as a result of tests with the first prototype. The second X-4 proved significantlymore reliable and as a consequence it wasdecided to drop the first prototype from the

ble canopy providing excellent visibility,although pilots found the cockpit extremelycramped. The aircraft's overall length was22ft 3in (7.lm), its wingspan was 26ft lOin(8.2m) and a long tailfin gave the X-4 a heightof 14ft IDin (4.5m). Nevertheless, most important parts of the aircraft were accessible fromground level during maintenance. Lusk drewheavily on experience gained during theXP-79 programme and many of the sameconstructional methods were employed forthe X-4. The body was mainly built from aluminium and wings were fabricated frommagnesium alloy with split flaps and elevonsfor control of pitch and roll.

Propulsion was provided by two Westinghouse XJ30 WE-7 turbojets (later replaced withnewer versions) that were housed within thewing roots. Each engine was rated at 1,600 lb(7.11 kN) static thrust. With a gross weight of7,8201b (3,550kg), the X-4's maximum speedwas 630mph (I,013kph) and the maximumendurance was about 45 minutes providing arange of approximately 420 miles (675km).

The X-4 prototypes had now been assignedthe serial numbers 46-676 and 46-677, with46-676 reaching completion in late 1948 andbeing transported by road to Muroc AFB on IS

In late 1945, the USAAF and NACA required asmall aircraft to explore control and stabilityissues at transonic speeds of around Mach0.85. The starting point for this project wascaptured research documentation for theGerman Me 163B rocket fighter and details ofthe British jet powered DH.I 08, which was inthe process of receiving Air Ministry approval.

NACA favoured a broadly similar single-seattailless design, although its aircraft would bepowered by two turbojet engines. Northropwas considered the obvious contractor tobuild this type of aircraft and towards the endof 1945 it was approached to develop two prototypes. The company then submitted plans tomeet this requirement and received provisional acceptance in spring 1946 for a designknown as XS-4 (and also MX-810). The orderwas formalised as a contract (WW33-038ac-14542) during June 1946 and the aircraftwas officially called the X-4, while unofficiallybeing given the name Bantam or Skylancer.

Northrop's senior engineer, Arthur I. Lusk,had been largely responsible for the X-4'sdesign and was placed in charge of construction which was undertaken at the Experimental Shop at Hawthorne. But beforeassembly work started, a one-fifth-scale sizewood and aluminium model was built forwind tunnel tests. By November 1946, a fullsized mock-up had been completed and areview panel recommended minor changesto the design which allowed the carriage ofextra instrumentation.

The X-4 was an extremely compact aircraftwith virtually no wasted internal space. Theforward-positioned cockpit was equippedwith an ejector seat and covered with a bub-

Northrop X-4

one option was to use the flying wing to 'knockwings and tails off other airplanes'. Later hewould indicate the role of the XP-79 was just tointercept and shoot down enemy aircraft andramming attacks had never been a seriousconsideration. But the weight of opinion suggests that there was a degree of interest in thispossibility, even if the XP-79 appears to havebeen unsuitable for such a task.

The first Northrop X-4 Bantam (46-676)undergoing checks at Rogers Dry Lake, California,during initial trials in late 1948. USAF

Northrop's second X-4 in flight. These smallexperimental aircraft were developed usingLippisch's research documentation for theMesserschmitt Me 163 and details of the post-warBritish de Havilland DH.108 Swallow. Designed toinvestigate transonic flight, the X-4 proved to be avaluable and successful experimental design. NASA

I (in prone position)38ft (I1.58m)278ft' (25.82m')14ft (4.26m)11ft 8in (3.55m)2ft lOin (0.86m)7ft (2.13m)5,8401b (2,649kg)8,6681b (3,931 kg)2xWestinghouse 19-8 (130)turbojets, each producing 1,150 Ib(5.1 kN) static thrust510mph (820kph)40,000ft (I2,192m)994 miles (I,600km)Armament 4x.50in (I 2.7mm)M2 machine guns, each with 250rpg

I (in prone position)36ft (I0.97m)255ft' (23.69m')30' (leading edge)II ft 4in (3.45m)3ft (0.9Im)13ft (3.96m) approx11,4001b (5,170kg)1xAerojet XCALR-2000A-l'Rotajet' liquid-fuelled rocketengine providing 2,000 Ib (8.89kN)thrust), plus six jettisonable RATOunits, each rated at 1,000 Ib(4.44kN) to assist take-off530mph (850kph) estimate45,000ft (I3,716m) estimateUncertain4x.50in (I2.7mm) M2 machineguns, each with 250rpg


CrewWingspanWing areaLengthChord at rootChord at tipHeightEmpty weightGross weightPowerplant

The completed Northrop XP-79B prototype jetfighter prior to testing at Muroc Dry Lake. USAF

The ultimately ill-fated Northrop XP-79B twin-jetprototype. Differences between this aircraft andthe original XP-79 are readily apparent due to thechange in propulsion and switch to twin stabilisingfins. Note the wingtip inlets for bellows typerudders, similar to those used on the XP-56. USAF

Maximum speedCeilingEnduranceArmament

Northrop P-79 Rocket Interceptor(Initial Proposal)

CrewWingspanWing areaSweepChord at rootChord at tipLengthGross weightPowerplant

destroyed. The exact cause of the accidentwas never fully determined, but it wasthought to be a control failure. As an immediate consequence of this accident, the projectwas cancelled.

It is often said that the sole purpose of thissmall fighter was to ram enemy bombers,hence the widely used name 'Flying Ram'.Jack Northrop allegedly told colleagues that

lifted offwith Harry Crosby at the controls andthe small flying wing flew for the next IS minutes, performing various aerial manoeuvres.Then at an altitude of about 7,000ft (2, 133m),Crosby started a slow roll, but failed torecover and the aircraft began to spin. Crosbyattempted to bail out but was struck by thetumbling aircraft and was killed. When theXP-79B hit the ground, it was totally

The rocket-powered XP-79 ran into majordifficulties due to its unsatisfactory propulsionsystem and was replaced by this alternative'Model B' version, equipped with two turbojetengines. Bill Rose Collection

by two separate stabilisers positioned abovethe rear of each turbojet housing producingan overall height of 7ft (2.13m).

By autumn 1945, the XP-79B had beencompleted and the small experimental jetplane was transported to Muroc to begin testing. After a series of taxiing trials at Muroc DryLake, the aircraft was finally ready to make itsfirst flight on 12 September 1945. The aircraft


The first prototype Northrop X-4 (46-676). ASA

Northrop X-4 Bantam

reference was normally applied to rath runusual aircraft of an experimental nature.

Fairchild' M-195 wa completely eliminated from the programme, but it wasdecided to proceed with the construction of amodified Martin B-57 as this appeared to be aworthwhile fallback option.

As work began on both of these aircraft,there were two new developments. First,some details of Project Bald Eagle reachedClarence L. 'Kelly' Johnson who headedLockheed's Skunk Works in California andsecondly, the CIA started to take a s riousinterest in the programme. Kelly Johnson'sapproach to business was aggressive and hehad no intention of allowing this project toslip from his grasp if his company was in aposition to compete. Subsequently, he initiated a series of studies at the Skunk Workswhich appear to have evolved in three slightlydifferent directions. The most conventionaldesign was a long winged one-man gliderlike aircraft with the design reference CL-2781-1. This had a wingspan of 98ft 8in (30m), awing area of 650ft' (60.3m') and utilised a tricycle undercarriage. Propul ion would beprovided by the forthcoming General ElectricJ79 turbojet (derived from the J73).

A second Skunk Works design for ProjectBald Eagl was the CL-282, based on Lockheed's prototype XF-I 04 Starfighter that hadreceived a USAF contract for further development in January 1953. The fuselage of this aircraft was similar in appearance to theStarfighter, although shorter with an overalllength of 44ft (13.4m). This was due to the usof a modified J79 turbojet that did not requirean afterburner. A cockpit (in this case unpressurised) and tail assembly of similar design tothe Starfighter would be used, but the L-282was not equipped with an undercarriage asSUCh, taking off with a trolley and landing onthe fuselage or perhaps small skids. Possiblythe mo t di tinctive feature of this aircraft wasthe proportionately wide 70ft 8in (21.5m)wingspan.

The third oncept intended to meet theBald Eagle requirement was the CL-278-1-2.This was very different from either of the otherhigh altitude reconnaissance proposals andwas based on a flying wing. It had a fuselage

Chapter Four

US Flying Wings (1950-1990)

version of the British twin-engine Canberralight bomber which had exceptional high altitude performance. The USAF version of thisaircraft was known as the B-57 and a smallnumber of these aircraft had been adaptedfor reconnaissance duties and were flying'Sneaky Pete' missions in the Far East.

Because the B-57 already possessed someof the abilities required for Bald Eagle, it wasdecided to explore the idea of making modest changes to the engines and wing toimprove high-altitude performance further.Seaberg and Lamar con idered this aircraft tobe a fairly safe bet, 0 Martin was issued witha contract (AF33(600)25825) to study a modified version of the B-57 which was designatedModel 294. The second contractor to beapproached was Bell Aircraft at Buffalo, ewYork, which was regarded a the leading constructor of experimental aircraft at that time.They were requested to design a completelynew lightweight twin-engine jet aircraft capable of meeting the requirement. A contract(AF33(616)-2160) was issued to begin workon this project and Bell assigned the company designation Model 67 to this aircraft. Thethird contractor chosen for Bald Eagle wasFairchild of Hagerstown, Maryland. It wasasked to undertake a design study for a single-engine, high-altitude aircraft. Fairchildreceived a contract (AF33(616)2182) andassigned the company reference M-195 to itsproject. The completion date for these studies was 31 December 1953 and all proposalshad been submitted by this date.

Although the USAF initially favoured adevelopment of the General Electric J73 turbojet for each design, every contractor recommended a modified version of the Pratt &Whitney J57. The three designs were nowconsidered in considerable detail, withSeaberg and Lamar presenting an outline ofProject Bald Eagle to everal group of USAFgenerals and receiving full approval to proceed during May 1954. Bell's Model 67 wasconsidered to be the best design and a contract was issued to build a mock-up of the aircraft, with the expectation of following thiswith a limited production run. The Bell aircraft was assigned the designation X-16which was intentionally misleading as this

As the Cold War intensified during the immediate po t-war years, the US sought r liableways of gathering intelligence on a wide rangeof activities taking place within the SovietUnion and other communist countries. Fewmethods were available to the US military orthe CIA and there were no aircraft capable ofundertaking deep reconnaissance missionswhile avoiding detection or interception.

At the start of the Korean War in 1950, USAFMajor John D. Seaberg found himself recalledto active service from his job as an aeronauticalengineer with Chance Vought. He was thenassigned to the ew Developments Office atWright-Patterson AFB, working under civilianscientist William E. Lamar. Before long,Seaberg was starting to produce ideas for a speciali ed reconnaissance aircraft that wouldutilise the latest developments in turbojet technology and aerodynamics, allowing flight atextremely high altitudes. With Lamar's full support he began to develop firm proposals, whichwere largely completed by the end of 1952.They called for a long-range, unarmed oneman reconnaissance aircraft, carrying photographic equipment for daylight use at aminimum altitude of 70,000ft (21 ,336m). It wasbelieved that the aircraft would be very difficultto detect at this height and would remainimpossible to intercept for some years to come.

The proposals generated immediate highlevel interest when presented in early 1953and Lamar received full backing to place thispromising programme on a formal footing.Within a matter of weeks, the proposal wasofficially named as Project Bald Eagle, withthe reference MX-2147. Three differentdefence contractors were carefully selectedto become involved with Bald Eagle and thefirst meeting with company engineers tookplace at Wright-Patterson AFB on 1July 1953.From the outset, large contractors such asBoeing, Convair and orthrop were excludedas it was felt that a smaller company wouldhandle the project more efficiently.

However, Martin Aircraft of Baltimore,Maryland, was chosen by Seaberg and Lamarbecause it was already building a modified

Lockheed High-AltitudeSpyplane Studies

I26ft lOin (8.2m)300ft' (27.87m')40· (leading edge)22ft 3in (7.1 m)14ft lOin (4.5m)5,5071b (2,498kg)7,8201b (3,550kg)2xWestinghou eXJ30 WE·7turbojets, later replaced by twoslightly improved Westinghou eJ30 WE-9 turbojets, each rated at1,600 Ib (7.11 k ) static thrust480mph (772kph)630mph (1,013kph)42,300ft (12, 39m)420 miles (675km)

CrewWingspanWing areaSweepLengthHeightEmpty weightGross weightPowerplant

Cruise speedMaximum speedService ceilingRange

Northrop X-4 (46-677) undertaking a test flight in1948. NASA

programme after just 10 test flights and use ita a source of spare parts for the second X-4.

The second X-4 made its first flight on 7June 1949 piloted by Tucker. The aircraft completed 20 flights before being passed over tothe USAF and NACA in 1950. A number of

SAF and NACA pilots flew the X-4 during trials that lasted until September 1953, with thebest known of these being Major Charles'Chuck' Yeager who had undertaken theworld's first supersonic flight in the Bell X-1.

Lengthy delays for various reasons held upthe test programme, although much waslearnt during this period about the behaviourof tailless aircraft at relatively high subsonicMach numbers. The X-4 demonstrated that itbecame increa ingly unstable at higherspeeds, although the nature of this wouldchange from yawing and rolling at aroundMach 0.75 to porpoising above Mach 0.9. Various attempts were made to counteract theseproblems with changes to the flaps and theelevon . There was some success and stability improved although the oscillations aboveMach 0.9 remained.

The research data provided by the X-4 had aconsiderable impact on the future of taillessdesigns, indicating that this type of aircraft wasunsuitable for supersonic flight. Both X-4s stillexist with the first aircraft currently in storageat Edwards AFB and the second on display atthe USAF ational Museum at Wright-Patterson Air Force Base, Dayton, Ohio.

The second Northrop X-4 research aircraft isshown split into two sections to facilitate relativelyeasy engine maintenance. 'ASA


aircraft being rearmed and refuelled whileattached. Two additional aircraft would becarried in a hangar bay and these may havebeen general-purpose designs able to ferrysmall numbers of personnel to and from theMe. It was also suggested that the MC couldact as an operational airborne command centre. The CL-1201-1-3 LSA was very similar tothe CL-1201-1-1 MC, but would be used totransport several hundred combat troops andtheir equipment to a war zone. One suggestion was to dock Boeing 707-sized transportaircraft using nose receptors positioned at theCL-1201-1-3's trailing edge and tail. However,the engineering challenge presented by thisidea would have been immense. Defensive

Two versions of the CL-1201 were proposed. The first was the CL-1201-1-1 AttackAircraft Carrier (MC) and the second was theCL-1201-1-3 Logistics Support Aircraft (LSA).Both aircraft would have facilities to accommodate as many as 845 crew members forone month. A version designated CL-1201-1-2would appear to have been considered, butnothing is held in the Lockheed-Martinarchives to indicate what this concept was.The CL-1201-1-1 MC version would carry 22multi-role tactical aircraft below the wing onpylons and these would be recovered in-flightafter completing a mission. There would bedirect access to the aircraft via pylons forflight crews and maintenance staff with the

nn~~ InIH~==:C==.i;=~.====• 11111 III III III

General arrangement of theLockheed CL-1201-1-1 nuclearpowered AAC (Attack AircraftCarrier). A known alternative wasthe CL-1201-1-3 LSA (LogisticsSupport Aircraft), which wouldfunction as an airborne controlcentre. Bill Rose/Pete Clukey atLockheed Martin

Perhaps the most astonishing proposal ever madefor a military aircraft was this massive nuclearpowered Lockheed aircraft carrier with the studyreference CL-120 J. Designed in the late 1960s, theCL-1201 would have taken off and landed usingbanks of lift jets. Once in the air, the CL-120Iwould have flown for one month on nuclear power.Combat aircraft would have been carried undereach wing and there was also a Star Trek stylehangar deck for transport aircraft. It remains hardto take this concept seriously and it seems unlikelythat anyone really expected such an aircraft to bebuilt. Lockheed Martin

With a diameter of 30ft (9.lm), the reactorwould provide a constant output of 1,830megawatts. Substantial shielding would beneeded to protect the crew and the reactorwould be designed to have failsafe crash performance even in a high-speed head-onimpact. CL-120 I would cruise at an altitude of30,000ft (9, 144m) and have an average speedof Mach 0.8. The estimated gross weight ofthe CL-2101 aircraft was about 5,265 tons(5,350 metric tons). The wingspan was to beapproximately I, 120ft (341 m) with a length of560ft (170m) and a height of 153ft (46m). Toput this in perspective, the length of the aircraft's fuselage would be almost the same asa Russian Typhoon-class nuclear poweredballistic missile submarine, which is thelargest submersible vessel ever built.

The aircraft could remain in flight for onemonth and this might be stretched furtherwith the reactor capable of operating for1,000 hours (41 days) before it required refuelling. Overall life expectancy of the reactorwas approximately five years. Because of theCL-1201's size and weight, it may have beeninitially designed as a flying boat, but company drawings show a VTOL capability,achieved by using 182 turbofan lift engines.These would provide 15 million pounds(66,723kN) of thrust and would be locatedalong each wing behind the rear spar and inextendable units at the front of the fuselage,each containing 24 units. The lift engineswould also be available for certain in-flightthrust manoeuvres.

The aircraft would be equipped with a substantial fully-retractable undercarriage comprising of four separate landing gear struts,each with six wheels positioned towards therear of the fuselage. Two further six-wheelunits would be located outboard of the wingroots, plus four-wheel stabilising gear positioned about half way along each wing. Inaddition, there would be a substantial fourwheel nose gear unit. The VTOL capabilitysuggests that this undercarriage would onlybe used for ground handling purposes, but itis possible that operations were consideredfrom specially built massive airfields.

Lockheed's Flying Aircraft Carrier

Among the more bizarre military studiesundertaken by any defence contractor was aLockheed Skunk Works project to determinethe feasibility of building a gigantic flying aircraft carrier or troop transporter for the USMilitary. With its origins in the late 1960s, thisproject evolved into a tailless aircraft designated CL-120 I that still looks as if it belongs ina science-fiction comic book. Four giganticturbofan engines would have powered theCL-120 I, providing a cruise thrust of500,0001b (2,224kn).

At altitudes below 16,000ft (4,876m), theengines would run on normal JP-5 fuel, butwhile operating at a greater height they wouldbe powered by nuclear energy from a singleonboard reactor. A liquid metal system wouldtransfer energy via a heat exchanger to a secondary non-radioactive system that was coupled to heat exchangers inside each turbofan.

Conceived in the late 1950s and built as a scalesized model, the Gusto 2 was an attempt byLockheed's Skunk Works to produce a high-altitudelow-observable subsonic aircraft. Lockheed Martin

Lockheed Gusto 2

At the end of the 1950s, a new, highly-classified proposal for a high-altitude flying wingreconnaissance aircraft was produced by theSkunk Works. This was regarded as a possible replacement for the Lockheed U-2 andthe cancelled Suntan supersonic spyplane.Gusto 2was a single-seat subsonic flying wingwith an estimated span of about 100ft(30.48m). It would be powered by two turbojets buried within the central section in a similar position to the Horten Ho IX. An air inletfor both engines was located in the nose andtwo vertical stabilisers were positionedtowards the wingtips. The aim of this designwas to produce an aircraft with a very lowradar cross section and it is known that anumber of scale models were built andtested. During trials, the design was found tobe incapable of avoiding Soviet radar systemsand this particular project was abandoned.

opments Office at Wright-Patterson AFB forCL-282, but Seaberg and Lamar rejected it.Johnson then undertook a significant revisionof the design and the CIA had now begun totake a serious interest in the Lockheed concept. It would lead to eventual acceptance ofa new Lockheed aircraft called the U-2A andcancellation of the X-16 which proved verydamaging to Bell Aircraft.

an ejection seat was contemplated for this aircraft. The nose of the aircraft was rounded,rather like the earlier Lockheed P-80A fighterand two film cameras would have been carried in this section of the aircraft. UnlikeCL-282, this high-altitude flying wing wouldhave been fitted with a tricycle undercarriage.No weights are quoted in what little documentation exists. However, it is reasonable toconclude that the maximum speed wouldhave been in the region of 500mph (804kph)with an expected operational ceiling of70,000ft (21 ,336m). The estimated range isunknown, but Lockheed will have intended tomeet the Bald Eagle requirements.

But it appears that CL-278-1-1 and CL-2781-2 were discarded within the Skunk Worksat an early stage, with CL-282 considered themost promising design. During May 1954,Johnson made a proposal to the New Devel-

c=LE:=:A()

-JF===~n==~A Lockheed Skunk works proposalfor a high-altitude spyplane with thecompany reference CL-278. This wasone of several designs considered forsuch a role during the early 1950s,which eventually led to the U-2A.Lockheed Martin

length of 42ft (l2.8m) and a single GeneralElectric J79 turbojet when available wouldprovide propulsion. This was the same enginechosen for the other aircraft in this study andit would be a slightly modified design with noafterburner and a static thrust in excess of11,0001b (49kN). The aircraft's wingspan was100ft (30.48m) and the long slender profileprovided a wing area of 650ft' (60.38m') witha leading edge sweep of 30°. Two triangularshaped stabilising fins with rudders werelocated towards the wingtips with control surfaces located alo~g the trailing edge. Theoverall length of the aircraft would be 48ft(l4.63m) when allowing for the vertical fins.

The cockpit would be positioned with thepilot sitting upright just ahead of the wing'sleading edge, allowing good visibility, andintakes for the engine would be located oneither side of the cockpit area. It is not clear if


""IIlJ

"U

"""

lems extended from continual failures ofminor components to deadly in-flight explosions! Of the 290 F7U-3s built, no less than 49were written off in accidents and in 25 casesthe pilots were killed.

Chance Vought F7U-3 Cutlass. Bill Rose Collection

cannon fire interfering with the engines, tolanding gear failure and stall recovery issues.Worst of all were the Westinghouse engineswhich never delivered adequate performance and were very unreliable. These prob-

assembled in Bernie Whitman's experimental shop. The first prototype XF7U-I flew on 29September 1948 at Patuxent River Naval AirStation with Vought's Chief Test Pilot, J.Robert Baker at the controls. Once the f1ighttesting was underway, the Navy placed anorder for the first batch of 14 F7U-I aircraft(124415-124428). But there were seriousproblems with the afterburning Westinghouse J34-WE32 turbojets that powered theprototypes and because of very real concernsabout safety and reliability. A major propulsion change was made with the next batch of16 (slightly improved) production aircraftdesignated F7U-3.

These were to have been powered byWestinghouse J46 turbojets, but the aircraftwere fitted with less powerful (non-afterburning) Allison J35-29 engines. The Allisonengines were less than ideal, but this substitution was regarded as a stopgap measureuntil Westinghouse resolved its technical difficulties and provided J46 engines that werereliable. While the first F7U-3 flew in December 1951, ongoing problems with the Westinghouse engines persisted and preventedthe F7U-3 from entering service until autumn1954. When the J46 finally became available,it failed to attain the anticipated level of performance. Key components would regularlyfail or wear out quickly and the enginesproved very difficult to maintain.

The Westinghouse J46-WE-8B wasexpected to deliver 7,0001b (31 kN) of staticthrust and about 10,000 Ib (44.5k ) with theafterburner, but in practice this engine neverprovided much more than about 60% of thepromised figure. This led to the aircraft beingnamed 'Gutless Cutlass' by Navy and MarineCorps pilots. The Cutlass served with the Navyuntil 1957, but never saw combat. It was usedprimarily as an interceptor that could justnudge past Mach I in a dive and many pilotsreported that the aircraft performedfavourably in mock dogfights. The fighter wasarmed with four 20mm cannons andunguided rockets while later versions carriedSparrow air-to-air missiles (AAMs). As a strikeaircraft, the Cutlass was capable of carrying6,000 Ib (2, 721.5kg) of ordnance which couldinclude a free fall nuclear weapon.

The Vought Cutlass earned a reputation forbeing a difficult and dangerous aircraft to fly.The design was plagued with problems from

Two US Navy F7U-3 Cutlass fighters on patrol.US avy

The first production Chance Vought Cutlass islaunched from the deck of USS Midway (CVB-4 I)on 23 July \95\ during carrier trials. US avy

The first prototype Chance Vought XF7U·\ Cutlass(I 22472), which undertook its maiden flight duringSeptember \948. NASA Langley Research Center

The first prototype Vought XF7U-\ (I 22472), seenin this photograph without nose probe. US Navy

The Cutlass

possible to build a massive aircraft likethe CL-120 1-1-1 and develop an advancednuclear propulsion system for it, the operational problems would be enormous. Suchan aircraft would be extremely demandingto operate, impossible to conceal and vulnerable to attack with the loss of a single multibillion dollar asset proving catastrophic.

In June 1945, Chance Vought Aircraft at Stratford, Connecticut, responded to a US avyrequirement for a future carrier-based combataircraft. The Navy now sought a jet fighter thatwas capable of reaching 600mph (965km/h)and attaining an altitude of at least 40,000ft(12,192m). Vought submitted several proposals and in June 1946, the Navy selected anadvanced tailless twin-engine design whichwould be designated XF7U-I. This aircraftpromised the required level of performance,combined with the minimal amount ofstowage space dictated by US carrier hangardecks. The aircraft was designed from the outset around engines equipped with afterburners and featured a pressurised cockpit, anejection seat and a tricycle undercarriage. Butthe XF7U-I, which eventually received thename Cutlass, had much in common with theArado Ar I jet fighter proposal (described earlier), leading to speculation that the XF7U-Iwas directly based on this design.

Vought claimed to have been working onthe Cutlass before any of Arado's wartimeresearch became available, but there is a consensus of opinion that the company receivedhelp from US Intelligence during early 1945.Alternatively, the XF7U-I proposal may havebeen extensively refined when documentation on the wartime Arado project becameavailable. Whatever the truth, the XF7U-I wasdeveloped by a team of engineers headed byRex Beisel (1893-1972) who designed thehighly successful Vought F4U Corsair fighter.Wind tunnel tests of XF7U-I models wereundertaken by NACA at Langley.

The XF7U-I was the last aircraft developedby Chance Vought at Stratford before theNavy orchestrated a company relocation toGrand Prairie, Texas, which began in 1948.Three prototypes (122472-122474) wereordered by the Navy and subsequently

1970s and the fact that it would never be builtmust have been obvious to many people fromthe outset. Nuclear propulsion for aircraft wasconceived at the end of World War 2 leadingto the Convair NB-36H prototype based on theB-36. This was followed by plans to build along-range nuclear powered bomber knownas WS-125.

Tests indicated that the concept wasviable, but there was strong political opposition due to the potential dangers of nucleartechnology and widespread public uneaseabout its use. In 1961, the Aircraft uclearPropulsion (ANP) programme was shutdown by the Kennedy administration and thatmay have been the end of any ideasto power aircraft with atomic energy. Whileproposals to use nuclear propulsion forspacecraft persisted into the early 1970s,these also met with increasing resistanceand were finally abandoned. But it is knownthat development of nuclear rocket engineswas secretly revived during the US StrategicDefence Initiative of the 1980s as a meansof lifting massive payloads into orbit andto power long-range high-performancemissiles. This work continued throughoutthe remainder of the 20th century and thereare suspicions that limited developmentof nuclear-powered aircraft or airborneplatforms may have continued in theblack domain. Nevertheless, even if it proved

Cruise speedCruise altitudeArmament

CL-1201-1-1 (AAC)

armament for the CL-120 I aircraft is unclear,although it is likely that long-range air-to-airmissiles such as the AIM-54 Phoenix wereconsidered. In addition, some of the combataircraft carried by the CL-120 1-1-1 wouldhave provided protection. It is also understood that the CL-120 1-1-3 may have beenable to launch battlefield range ballistic missiles with nuclear warheads.

Few details of the CL-120 I study remain,but most elements of this concept are hard totake seriously. Lockheed worked on this ideafor an unknown period, lasting into the early

Wingspan 1,120ft(34Jm)Wing area I25,000ft' (I 1612.8m')Length 560ft (I70m)Height 153ft (47m)Gross weight 5,265 tons (5,350 metric tons)

approx.4x turbofan engines, providing500,000 Ib (2,224kn) cruise thrust,combined with one nuclearreactor producing 1,830megawaUsMach 0.830,000ft (9, 144m)Fighter aircraft carried by theCL-120 I, upplemented by longrange air-to-air missiles for defence

Powerplant


Problems persisted with the generallyunsatisfactory Westinghouse XJ40-WE-6 turbojet, although units were provided for installation in both prototype aircraft. Theimproved performance allowed XF4D-I(124587) flown by Navy Lt-Cdr James B.Verdin to set a new world air speed record of752.944mph (l211.746kph) over a !.86 mile 9(3km) course above the Salton Sea, California, on 3 October 1953.

But the Westinghouse engines remainedunreliable and liable to failure in flight, some-

Douglas F4D-l Skyray.Bill Rose Collection

cockpit canopy that was not adopted. TheSkyray continued to exhibit various controlproblems that needed to be addressed andwas the first Douglas aircraft to show signs ofinertia coupling at high roll rates. Nevertheless, the Navy was sufficiently impressed toorder a small batch of production F4D-Is inFebruary 1951. With work underway on theseaircraft, the Navy then placed an order for asecond batch of 230 Skyrays in early 1952which would be manufactured at the company's plant at Torrance, California.

I xPratt &Whitney J57-P-8, 8A, or88 turbofan providing 1O,2001b(4,627kg) static thrust and 16,0001b(7,258kg) with afterburner640 US gal (2,422litres)Two ISO US gal (568 litre) ortwo 300 US gal (I, 135 litre)drop tanksFour 20mm cannons in wings andseven fuselage/underwinghardpoints able to carry up to4,0001b (I,815kg) in stores.

demanding with Peyton reporting variouscontrol and handling problems and he neverflew another Skyray. The aircraft was thentest flown by Douglas test pilots Russ Thawand Robert O. Rahn who both reported problems with yaw immediately after the undercarriage was retracted and unusualdifficulties controlling pitch. Some years later,Rahn wrote his memoirs in a book calledTempting Fate and he had the following tosay about the aircraft. 'I flew on manual flightcontrol and quickly learned why Larrywanted no part of the Skyray. The stick forceswere exorbitant for the small control-surfacedeflection achieved. The plane was tough tohandle unless below 200kts and in smooth air- not a good sign for a fighter.' That aside,Rahn went on to praise the Skyray's agility,describing it as the best machine he hadflown since the Spitfire.

The second prototype featured minorexperimental differences such as a sliding

A Douglas F4D landing on the aircraft carrier USSBon Homme Richard during 1957. US Navy

Douglas F4D-I Skyray

A Douglas F4D-l equipped with drop tanks andSidewinder MMs above San Diego, California.US Navy

Armament

Crew IWingspan 33ft 6in (l0.2m)Wing area 557ft' (5l.8m')Length 45ft 3in (l4.5m)Height 13ft (4m)Wing loading 41Ib/ft' (l98kglm')Empty weight 16,0241b (7,268kg)Combat weight 22,6481b (l0,272kg)Gross weight 25,0001b (l1,339kg)Max permissible weight 27,1161b (l2,299kg)Maximum speed 722mph (I,162kph)Cruising speed 520mph (837kph)Landing speed 134mph (2 I5kph)Initial rate of climb 18,300fVmin (5,578m/min)Ceiling 55,000f! (l6,764m)Range (external tanks) 700 miles (I, I26km)Ferry range 1,200 miles (I,93Ikm)Powerplant(production aircraft)

Internal fuel capacityExternal fuel capacity

A Chance Vought F7U-3 Cutlass on the ramp atJacksonville Naval Air Station in June 1954.US Navy

Douglas on 16 December 1948 for the construction of two prototypes receiving the official designation XF4D-I and the BuAer serialnumbers 124586 and 124587. It remainsunclear when the name Skyray was appliedto the design by Douglas or when it was officially adopted, but it appears to have comeinto use soon after construction started. Military pilots would later know the Skyray as'The Ford' because of its F-4-D designation.

The XF4D-I was a low-aspect ratio sweptwing tailless aircraft, falling somewherebetween a flying wing and a delta design witha single tailfin. The aircraft was to be poweredby one of the new afterburning Westinghouseturbojets, fed from air intakes located at theleading edge wing roots. The XF4D-I wouldbe equipped with a tricycle undercarriage,folding wings for hangar deck storage and aforward-positioned pressurised cockpit fittedwith an ejector seat developed by Douglas.Production aircraft would be fitted with four20mm M-12 cannons in the wing's inner leading edges and use a forward located Westinghouse radar system. Provision was also madefor the future carriage of underwing stores,including drop tanks and air-to-air missileswhen they became a practical proposition.

The production aircraft would have an overall length of 45ft 3in (l4.5m) and a wingspanof 33ft 6in (l0.2Im), making it similar in size tothe Vought Cutlass and, with the wings folded,would occupy much the same storage spacewithin an aircraft carrier's hangar deck. TheNavy had specified the Westinghouse XJ-40WE-6 afterburning turbojet for the Skyray. Itwas rated at 7,0001b (31.13kN) static thrustand Douglas was confident that its new fighterhad the potential to reach Mach I in level flightwith this engine. The Westinghouse turbojethad been chosen to power several other Navyaircraft, but it was experiencing serious development problems that led Heinemann tomake modest alterations to the XF-4D-I's airframe, allowing the installation of alternativeengines with diameters up to 42in (I.06m).

This proved to be a shrewd decisionbecause when the airframe was completedin early 1950, the Westinghouse turbojet wasstill unavailable due to ongoing technical difficulties. As a consequence, it was decidedduring June 1950 to install the less powerfulAllison J35-A-17 providing 5,0001b (22.24kN)static thrust in each prototype for trial purposes. Subsequently, the first XF4D-I(124586) took to the air on 21 January 1951 atEdwards AFB, piloted by Douglas' test pilotLarry Peyton. The flight proved to be quite

Douglas Skyray

The manta-shaped Skyray jet fighter was aproduct of Douglas Aircraft at EI Segundo,having been designed by Edward 'Ed' HenryHeinemann (1908-1991) who drew heavily onwartime research undertaken by Dr Alexander Lippisch. The history of this aircraft beganthe week after Germany's surrender whenDouglas Aircraft's leading aerodynamicists, L.Eugene 'Gene' Root and Apollo Milton Olin'Amo' Smith, were sent to Paris. The purposeof their trip was to meet with Dr Lippisch(who was in Allied custody) and to secure hisresearch data on tailless high-performanceaircraft.

Root and Smith were very impressed withLippisch's work and following considerableevaluation of the data at Douglas, a programme of wind tunnel model tests began in1946 which produced very encouragingresults. Perhaps already aware of the Navy'sfuture needs, Heinemann concentrated onthe design of a tailless jet fighter and when theNavy's single-engine fighter competition wasannounced in 1947, Heinemann's projectreceived the company reference Design-57!.The Navy was seeking a carrier-based jetfighter capable of intercepting an enemybomber which was travelling at 575mph(926kph) at an altitude of 50,000ft (l5,240m)within a 100-mile 160km radius. Five minuteswas allowed from the start of the alert to interception and engagement, which was a toughrequirement to meet with prevailing technology, but Heinemann was convinced that the0-571 could meet this demand.

Initially, the fighter was very reminiscent ofa Lippisch study taking the form of a deltashaped flying wing with no significant fuselage and a single tailfin. But as the designevolved, the aircraft began to stretch and thefuselage took a more distinctive shape. Withthe concept formalised, a proposal was madeto the Navy that decided to issue a contract to

I38ft 8in (l1.78m)38' (leading edge)39ft 7in (l2.06m)11ft lOin (3.61m)12,8401b (5,824kg)24,0001b (l0,886kg)2xWestinghouse J34-WE-32Aafterburning turbojets, each ratedat 4,200 Ib (l8.68kN) static thrust672rnph (I,08Ikph)at 20,000ft (6,096m)665mph (I ,070kph) at low level44,000ft (13,41 1m)600 miles (965km)Four 20mm cannon and threethree-packs of Mighty Mouse(FFAR 2.75in) rockets (two onthe wings, one under the fuselage)

I39ft 8in (l2.lm)44ft 3in (l3.5m)14ft 7in (4.45m)496ft' (46.08m')31,6421b (l4,353kg)18,2101b (8,259kg)2xWestinghouse J46-WE-8Aafterburning turbojets, eachproviding about 4,600 Ib (20.46kN)static thrustClean: 680mph (I,095km/h)at 20,000ft (6,096m)648mph (I,042kph)44,000ft (13,41 1m)1,400 miles (2,253km)with two drop tanksFour 20mm cannons above inletducts, 180rpg. Four AIM-7 Sparrowair-to-air missiles, or up 6,000 Ib(2,721.5kg) of external stores

CrewWingspanSweepLengthHeightEmpty weightLoaded weightPowerplant

CrewWingspanLengthHeightWing areaMax take-off weightEmpty weightPowerplant

CeilingRangeArmament

Maximum speed

Vought F-7U-3 Cutlass

Carrying missilesCeilingRange

Armament

Maximum speed

Vought F7U-I Cutlass


tion that almost blends into the body with theleading edge beginning next to the centre ofthe forward-positioned cockpit. The aircraftwould be powered by two unspecified nonafterburning turbofan engines, largely buriedwithin the wings and fed by leading edge airintakes on either side of the wing roots. Thissuggests that some consideration was givento reducing the radar signature of the aircraft.There is no tail, but there are two slightlyinward leaning tail fins with rudders which

cessor to the Viking that would be similar insize, but capable of being easily configured tomany different tasks. Northrop was onedefence contractor to conduct studies for apossible multi-role successor to the Viking S-3with a definitive design known as N-381which has its origins in the early 1980s.

Some details of N-381 remain sensitive andare not available, although the design wasbased on a compact fuselage not totally dissimilar to the S-3 with a substantial wing sec-

This drawing of Lockheed's proposed taillessL-187 carrier-based bomber clearly shows themulti-engine layout for a design that stretchedthe limits of what was technically possiblein the late 1940s. Pete Clukey/Lockheed Martin

a forward-positioned tandem cockpit. Thesubstantial swept wing would be fitted withsplit flaps and elevons, plus wingtip stabilisingfins and rudders. CL-187-3 used three turbojets for propulsion with two mounted abovethe wings in nacelles that extended beyondthe trailing edge. The third engine was locatedin a dorsal fairing at the centre of the wing. Forhangar storage, the wings would fold and thecrew access to the bomb bay was required toarm a nuclear weapon. Presumably, this aircraft was also capable of accommodatingconventional bombs and perhaps carryingphoto-reconnaissance equipment. Two20mm cannons would have been fitted in arear remote-control tail unit which was arequirement of OS-III. No details of dimensions, weights or performance for this ratherobscure proposal appear to have survived, butthe wingspan was probably in the region of85ft (25m) to 90ft (27.4m). Maximum speedwould have been about 500mph (804kph)with a ceiling of 40,000ft (12, 192m). Nothingcame of this interesting design and the scantdetails of CL-187-3 remained in Lockheed'sarchives until relatively recently.

Northrop N-381

During the 1970s, the Navy began to replaceits propeller-driven anti-submarine warfare(ASW) Grumman S-2 Tracker aircraft with themore advanced turbofan-powered LockheedS-3 Viking. The Viking was developed by aconsortium of companies headed by Lockheed that built the airframe, supported byLing-Temco-Vought (LTV) and Univac Federal Systems. Although the four-man Vikingwas designed primarily for ASW operations, itwas capable of undertaking many otherduties and a 'Weapon Systems ImprovementProgram' (WSIP) was initiated in 1981, leading to the S-3B Viking. This versatile subsoniccarrier-based aircraft could easily be adaptedto anti-shipping operations or used to attackland targets. Vikings have also been used forrefuelling purposes, sea surveillance andeven trialled as airborne early warning (AEW)platforms.

The Viking has been used in many differentmilitary campaigns which include the firstGulf War, the Balkans War and operations inAfghanistan. At the time of writing, the Navy isexpected to keep the Viking in service untilabout 2015. But since the early 1980s, theNavy has been considering an eventual suc-

The Northrop N-381 multi-role carrier-based flyingwing aircraft designed as a possible replacementfor the Grumman S-2 Tracker and Lockheed S-3Viking. George Cox/Bill Rose Collection

US Navy Douglas F-6A Skyray (139083) photographedat MCAS EI Toro, California, during July 1964. Theaircraft shown was being used for training purposes.US Dept of Defense

Lockheed Naval Jet Bomber

Douglas F4D-1 Skyray (134806) belonging toVMF-542 of the US Marine Corps. US Dept of Defense

During 1947, the US Navy's Bureau of Aeronautics (BuAer) produced a preliminaryspecification for a carrier-based jet bomber.This document known as OS-III was issuedto 14 major aircraft contractors in December1947. BuAer sought a fast jet aircraft capableof carrying a single atomic weapon (Mk3Fat Man plutonium bomb) with a weight of10,2001b (4,630kg), a length of 10ft 8in(3.25m) and a diameter of 5ft (I.52m) to atarget 2,000nm (2,300 miles or 3,700km) distant and returning to the carrier.

The military think-tank Project RAND(Research ANd Development) had suggestedthat 150,0001b (68,000kg) should be the minimum gross weight considered for an aircraftundertaking such a mission. However, BuAerdecided this was an unrealistic demand, evenallowing for the 1,088ft (331 m) flight decks ofthe five proposed 'Supercarriers', so they setthe gross weight at 100,000 Ib (45,359kg). Morethan half the contractors approached hadsoon dropped out stating they felt it wasimpossible to balance the requirement for abomber with this gross weight against a compact design that used prevailing or near-termengine technology. The remaining contractorsindicated that performance compromiseswere necessary and progressively abandonedthe contest, leaving a design produced by Curtiss and a lightweight proposal from Douglasthat was capable of operating from a 45,000ton (40,823-metric ton) Midway class carrier.

Then on 23 April 1949, the five supercarrierswere cancelled and two months later Douglasreceived a development contract to build twoXA3D-I prototypes and a static test airframe.Among the numerous earlier proposals forOS-III were two Lockheed designs whichhad different types of engines but broadly similar features. Both featured swept wings andtails with twin underwing engines, either forturbojets or turboprops. Designated with thecompany reference CL-187 (also referred toas L-187 in some documents), these designsresembled something of a cross between thelarger B-47 and the smaller Douglas A-3.

A third completely different proposal wasthe CL-187-3 flying wing. This design comprised a short fuselage section with no tail and

-~

Skyray was seldom configured for this role.The first production fighters reached the

Navy in early 1957 and the US Marine Corpsbegan receiving Skyrays soon after this. Withmany of the initial bugs ironed out, the Skyrayproved to be reliable and reasonably popularwith pilots. It never saw combat but wasdeployed operationally during two separateperiods of international tension. The first wasTaiwan in 1958 and then throughout the 1962Cuban Missile Crisis when fully-armedSkyrays patrolled from the Naval Air Station atKey West, Florida, and Guantanamo, Cuba.In total, 421 Skyrays were built with the aircraft designation being changed to F6A. TheSkyray was finally retired in 1962 when it wasreplaced by the outstanding McDonnell F-4BPhantom II.

Heinemann followed the Douglas Skyraywith a naval attack aircraft called the A-4 Skyhawk which used the same basic design philosophy of compactness and functionality.The Skyhawk entered production in 1954 andcontinued to be built until 1979. Some 2,980examples were sold to the US Navy, MarineCorps and a number of overseas customersmaking it one of the company's most successful products.

times with catastrophic results. The upshot ofthis was a decision taken in March 1953 toadapt the Skyray to accept the more powerfuland more reliable Pratt & Whitney J57-P-2axial-flow afterburning engine that had ananticipated rating of 10,000 lb (44.48kN) staticthrust. Trials of a Westinghouse-poweredXF4D-I onboard the USS Coral Sea continued, but the fate of this engine was nowsealed and Westinghouse soon found itselfout of the jet engine manufacturing business.

The first Skyray powered by a J57 flew on 5June 1954 and the re-engined fighter soonshowed itself to be a more capable aircraftthan initially envisaged. It had a maximumspeed of almost Mach I, an outstanding rateof climb and a ceiling in excess of 50,000ft(l5,240m). The maximum take-off loadedweight was 27,1161b (l2,299kg) that waspartly due to the use of two 300 US gal (1,136litre) fuel tanks, which extended the operational range to about 700 miles (I, 126km),depending on the mission profile. Ferry rangewas somewhat greater at 1,200 miles(I,93Ikm). Although designed from theoutset as a high-performance interceptor,changing requirements resulted in adaptation to a limited strike capability, but the


cec C::1::

The CL-1170-4-1 emerged from a late 1960sLockheed study to produce an advancedreplacement for the land-based LockheedP-3 Orion maritime patrol aircraft. Thisstudy was sponsored by the US Navy's NavalAir Systems Command (NAVAlR) at PatuxentRiver, although not developed further.Pete Clukey/Lockheed Martin

The Advanced Tactical Aircraft A-12AAvenger II

During the mid-1970s, the US Navy began totake a serious interest in the pos ibilitiesoffered by an aircraft using 'low observabltechnology'. Lockheed and Northrop werealready working on a top-secret 'radar invisible' interdictor project for the USAF whichappeared to be progressing well. However,the Navy wanted a 'stealth' warplane and itwas decided to embark on a more ambitiousprogramme with seemingly little concernabout the massive cost that would beincurred.

===~=I===

This advanced four-engine design fromLockheed's 1968 long-range maritimepatrol study has the referenceCL-1170-6-2 and was expected toprovide superior performanceto any similar conventional design.Pete Clukey/Lockheed Martin

development of this advanced study andapparently no preference was stated for aspecific design by AVAIR.

The CL-II 70 project was the subject of aFreedom of Information Request to NAVAIRduring the writing of this book. However,despite considerable assistance from thisoffice, it was not a cost effective propositionto undertake a full search for details of

L-1170 and most of the information used inthis section is based on documents providedby Lockheed-Martin. Currently, the Navy's P-3Orions will start to be replaced in 2010 by the80eing P-8 Poseidon which is a developmentof the 80eing 737-800.

10131ft (40m)I,890ft' (J 75m')25' (leading edge).97ft (29.5m)27ft (8m)150,000 lb (68,038kg)2xadvanced high-bypass ratioturbofans each rated at 22,500 Ib(J OOk ) static thrust. Alternatively,2xadvanced turboprop enginesUnspecifiedUnspecifiedMk46 or Mk50 torpedoes, mines,depth charges, free fall bombs,AGM-84A Harpoon missiles,AGM·65F Maverick air·to· urfacemissiles

Unknown224ft (68m)5,000ft' (4645m')95ft 6in (29m)36ft 9in (11m)500,000 Ib (226,796kg)4xadvanced high-bypass ratioturbofans or 2x turbofans and2x turbopropUnspecifiedUnspecified90 hours at amission radius of3,000nm (3,452 miles, or 5,556km)u ing mixed turbofan/turboproppropulsion ystemUnspecified, but probably similarto CL-1170-4-1

CrewWingspanWing areaSweepLengthHeightGro sweightPowerplant


CrewWingspanWing areaLengthHeightGross weightPowerplant

Armament

Maximum speedCeilingEndurance

Lockheed CL-1170-4-1

Lockheed CL-1170-6-2

would be capable of in-flight refuelling.Engines for the all-wing designs were sus

pended in pods beneath the wing with theirthrustline positioned at the chordline. Thefour-engine versions of the all-wing aircraftwould be fitted with two additional engines innacelles supported by struts on each side ofthe lower forward tailfin section. With mixedpropulsion designs it was determined that theturboprops needed to be installed in the outboard locations. The smaller tailless aircraftwas intended to carry similar armament tothe P-3 Orion, ranging from free fall bombs,various missiles, torpedoes, mines and depthcharges. There would also be provision forsonobuoys. There are no details of externalhardpoints and the capability of the larger allwing aircraft is unknown, but it would be similar or slightly better. No action was taken on

Lockheed Long EndurancePatrol Aircraft

During 1968 the US Navy's Naval Air SystemsCommand (NAVAIR) at Patuxent River, Maryland, began to consider future requirementsfor an aircraft that could replace and improveon the very reliable and extremely versatileland-based Lockheed P-3 Orion maritimepatrol aircraft that had been in service since1962. This resulted in Lockheed beingapproached to develop new designs thatmight be introduced in the late 1970s. Thecompany accepted the commission andbegan a six-month programme whichreceived the umbrella reference CL-1170. Itsemphasis was on long-duration missions.

Initially, the designers looked at fairly conventional two- and four-engine designs thatwere configured to meet two different grossweight requirements of 150,000 Ib (68,038kg)and 500,0001b (226,796kg). The smaller aircraft would have a fuselage that was similarto the P-3 Orion, giving it an overall size thatwas close to a 80eing 737. The larger aircraftwould be somewhat similar to a 80eing 747.

A parallel series of studies considered twodifferent sizes of all-wing aircraft which weredesigned to the same overall gross weightrequirements. These concepts incorporatedlaminar flow control and anticipatedadvances in high-bypass ratio turbofanengines allowing lengthy, fuel-efficient loitering. Mass would be carefully controlledthrough the use of composite materials andaluminium alloy wherever possible. At theend of this study, Lockheed engineers determined that the larger CL-1170-6-2 all-wingdesign using a mixture of turbofan and turboprop propulsion would perform better than itsconventional equivalent on long-range missions. This was due in part to the proposedlaminar flow control.

The CL-II 70-6-2 would have a projectedendurance of 90 hours and a mission radiusof 3,000nm (3,452 miles, or 5,556km) and itappears that four turbofans became the preferred choice for this tailless aircraft, offeringslightly better all-round performance. In thecase of the smaller all-wing aircraft, it seemsthere were no significant gains over the conventional design. Under CL-1170, Lockheedconsidered six different basic configurations(conventional and all-wing), with outlines forseveral variants. Each aircraft utilised multiple wheel, tricycle landing gear, although thesmaller all-wing design was expected torequire outriggers to ensure stability. Othercommon design features for the all-wingaircraft were elevons and flaps, plus a singlelarge tail fin with a rudder. All versions

UU \i\; CD

inwards would be to assist with wing foldingduring storage. The overall length of the aircraftwas 47ft 6in (14.4m) and the height was 18ft(5.5m). N-381 would have a maximum speedin the region of 520-550rnph (836-885kph) anda ceiling of about 40,000ft (12, 192m).

This design was finally rejected for unknownreason , but the Common Support Aircraft(CSA) project began in 1993 with the intentionof finding a single design capable of replacingthe S-38 Viking, ES-3A Shadow surveillance aircraft, E-2C Hawkeye airborne AEW platform,£A-68 Prowler EW aircraft and C-2A Greyhound transporter. Although there would bedifferences between each variant, the basicairframe and propulsion system would be standardised, leading to obvious advantages withmaintenance and training, while theoreticallyreducing the cost of manufacturing.

However, financial restraints and the focusof attention switching to programmes like theF/A-18FJF Super Hornet and the Joint StrikeFighter (now F-35 Lightning II) caused the CSAprogramme to slow. CSA Phase II began in1997 with Lockheed-Martin as an active participant. They suggested improvements to theS-3 Viking, followed by an advanced canardvariant equipped with a triangular shapedradome that was mounted on the tailfin. Thiswas followed by various unusually-shapedproposals with stealthy characteristics. TheCSA project remains on the shelf and it wouldbe too costly to implement at present. Asthings stand, the F/A-18 Super Hornet haslargely replaced the S-3 Viking in the anti-shipping and tanker roles. The £A-68 Prowler isalso being superseded by the £A-18G Growlerderived from the Super Hornet and there hasbeen a reappraisal of ASW missions.

It is impossible to predict developmentof carrier-based aircraft during the next20-30 years, but the introduction of a newmulti-role manned aircraft seems unlikely inthe near-term.

Three-view drawing of the Northrop N-381 multi-role aircraft showinginternal carriage of two AGM-84A Harpoon missiles. Bill Rose Collection

are mounted above each engine unit towardsthe trailing edge. The wing is fitted withelevons and split flaps, while also having theability to fold for hangar deck storage.

The forward-positioned four-man pressurised cockpit appears fairly similar to the£A-68 Prowler design, although the windshieldis slightly different. All crew members facedforward in ejector seats with a pilot and copilot in the front seats and system specialistsbehind. The total number of roles envisagedfor the N-381 remains undisclosed, but it wasprimarily designed as an ASW successor to theLockheed S-3 with the probable ability toreplace several other Navy aircraft. Typically,the N-381 would carry two banks of sonobuoylaunchers, chaff and flare dispensers and twoAGM-84A Harpoon missiles internally.

Alternatively, the aircraft could carry Mk46or Mk50 torpedoes, mines, depth charges,free fall conventional bombs and 857 or 861nuclear weapons. Four underwing pylonswould allow additional stores. These couldbe AIM-9 Sidewinder AAMs for self-defence,AGM-88 high-speed Anti-Radiation Missiles(HARM), AGM-65F Maverick air-to-surfacemissiles, free fall bombs, unguided rockets,fuel tanks or various specialised pods.

The N-381 would be equipped with radarmodules at the front and rear of the fu elage. Inaddition to ocean surveillance, Northropalmost certainly proposed a variant that wasspecifically designed to replace the £A-68Prowler electronic warfare aircraft. The N-381would be capable of in-flight refuelling andcould be configured as a refuelling aircraft.Generally speaking, it seems reasonable tosuppose that this design was expected to provide significant improvements over the S-3Viking. N-381 would utilise a fully-retractabletricycle undercarriage and arresting gear. Thewingspan was 70ft (21.3m) with an estimatedleading edge sweep of 42° and it is probablethat part of the reason for angling the tail fins

104 Secret Projects: Flying Wings and Tailless Aircraft US Flying Wings (J950-1990) 105

Several modest research projects werealready underway, but in 1983, the Navy officially began its Advanced Tactical Aircraft(ATA) project that aimed to replace the carrierbased Grumman A-6 Intruder with a versatileand highly sophisticated stealth strike aircraft.General Dynamics had been undertaking studies into stealth technology for the Navy andnow teamed up with McDonnell Douglas towork on a flying wing design for the ATA project. In direct competition were Northrop inassociation with Grumman and Ling TemcoVought. At the present time, large gaps exist inthe early history of the ATA project, but it seemsprobable that General Dynamics and Northropboth received black budget funding to producewind tunnel, radar and flying models, followedby scale-sized, manned demonstrators.

An early General Dynamics concept for amanned stealth aircraft received the codename Cold Pigeon. This 1970s design was aflying wing, with rounded wingtips. Powerwould be provided by two deeply buried turbofan engines, fed by leading edge intakes,with trough-shaped exhaust ducts in the central area of the trailing edge.

Cold Pigeon was built as a scale model andit may have also been known as Sneaky Pete.An alternative stealthy proposal from GeneralDynamics and McDonnell Douglas was aswing-wing strike aircraft resembling a crossbetween the F-14 and F-III with a Mach 1.5capability. Known as Configuration 403, itprogressed no further than the initial designstage. Lockheed also submitted plans for anavalised version of the F-117 during thisperiod, but the NavYrejected this aircraft dueto its limited range and payload capability.

The appearance of Northrop's ATA proposal remains unclear, although the initialdesign is thought to have resembled a smallertwin-engine version of the B-2A bomber. It isalso possible that Northrop produced a twinengine arrowhead shaped design and USPatent Des: 342,717 filed on 29 October 1992may provide some indication of how thislooked. Whether or not small manneddemonstrators were built and tested for theATA programme remains a matter of speculation, but it has been suggested thatNorthrop built at least one proof-of-conceptaircraft. It is also rumoured that GeneralDynamics produced a scale-sized prototypecalled the Model 100, which bore someresemblance to the later A-12A.

Assuming there were tests of manned ATAdemonstrators during the 1980s, these wouldhave been flown from China Lake, California,or Groom Lake, Nevada, perhaps being occasionally glimpsed by the public and reportedas triangular-shaped UFOs. While there is no

documentation to prove these aircraftexisted, the sheer scale and importance ofthe multi-billion dollar ATA programmewould suggest that this project did not proceed from testing models to full-scale production without any form of prototyping.

On 13 January 1988, the Navy finallyselected the General Dynamics design for further development; a contract ultimatelyworth around $4.5 billion was issued whichrequested an initial four test and eight preproduction aircraft. The designation of thisnew aircraft would be the A-12A, although anofficial name had yet to be chosen. Congresswas exerting pressure on the USAF to accepta version of this aircraft as a replacement forthe aging F-III and despite some resistancewithin the Air Force, General Dynamics wasawarded a $7.9 million contract to study a version more suited to USAF needs. Although theproject had become public knowledge, thedesign of the Navy's new aircraft remained amystery. In 1989, a number of names wereconsidered for the A-12A which included theAvenger, Enforcer, Ghost, Penetrator, Seabat,Shadow and Stingray. These names werereleased to the public domain and somehinted at what the aircraft was like. The finalchoice was Avenger 11 which must have beenmet with a degree of anger by Grumman whobuilt the original wartime Avenger aircraftand had lost out on the ATA programme.

It is known that different forward engineinlet positions and contoured wingtip stabilising fins were considered for the GeneralDynamics A-12A design. There were also various engine exhaust systems tested with oneconfiguration ducting air into the exhauststream via upper and lower slots in the rearfuselage. The final appearance of the aircraftwas a very clean triangle with few protuberances. The wingspan of the A-12A was 70ft 3in(21.4m) and this reduced to 36ft 3in (11m)when the wings were folded for hangar deckstorage. With a length of 37ft 3in (l1.35m),this produced a wing area of I ,308ft' (122m').The overall height of the aircraft was II ft 3in(304m). The A-12A was fitted with a fullyretractable tricycle undercarriage and composite materials were used extensively in theaircraft's construction.

General Dynamics and McDonnell Douglasboth asserted that maintenance would behalf that of the A-6 and reliability wasexpected to be better than any other aircraftin Navy service. Although undoubtedly true, ithas been suggested that the special surfacecoatings required for this aircraft to reduce itsradar signature were susceptible to damagein the harsher marine environment and thiswould have become a significant issue.

The gross weight of the A-12A was set atabout 80,0001b (36,300kg) which included15,0001b (6,803kg) of ordnance. Designed asa subsonic aircraft with a maximum speed of580mph (930kph), propulsion was providedby two deeply buried General Electric F412GE-D5F2 non-afterburning turbofans, eachrated at 13,0001b (58kN). Each engine wouldbe fed from two trapezoidal intakes at thelower leading edge linked by stealthy inletducts. The F412 engine was based on thedesign used for the F-117A and it providedslightly better thrust, although supersonicspeed was never a consideration with theA-12A as it degrades the ability to hide fromradar. While the A-12A was not intended toundertake air combat, it was expected to bevery agile due to its low wing loading andhighly sophisticated flight control systern. TheA-12A's service ceiling remains unclear, but itwould have been in excess of 40,000ft(l2,200m) and the un-refuelled combatradius was about 800nm (920 miles, or1,480km).

Flown by a crew of two in a tandem-configured cockpit, the primary role of the A-12Awas to attack heavily defended land targets orshipping in all weather conditions and atnight. A mission well suited to this aircraftwould have been the surprise attackmounted against targets within the Libyancapital Tripoli during April 1986. Known asOperation 'Eldorado Canyon', it was undertaken by F-III s flown from England and Navycarrier-based F-18s. The still secret F-117 wasconsidered but it lacked sufficient range. Nevertheless, there can be little doubt that thisoperation encouraged the Navy to proceedwith development of the A-12A. In addition todelivering bombs (conventional and nuclear)or air-to-surface missiles, the A-12A couldcarry two High Speed Anti-Radiation Missiles(HARM). For self-defence, four (later two) airto-air missiles (AAMs) would be carried internally. The options were AIM-9 Sidewinders orAIM-120 Advanced Medium Range Air-to-AirMissiles (AMRAAM). These weapons wouldbe supported by an advanced WestinghouseAN/APQ-183 multimode radar systemthat would also provide high-resolutiongroundmapping and surface search capabilities. In addition, the A-12A would have used asophisticated threat management systemknown as Radar WarningReceiver/Electronic Support Measures(RWR/ESM).

The Navy planned to buy no less than 620copies of the A-12A and the US Marine Corpswas considering a further 238 aircraft. In addition, the USAF was being encouraged to purchase 400 of the land-based variant

This aircraft would have lacked the arrestergear and folding wings necessary for carrierbased operations and there will have beensystem and weapons carriage differences. Itis also believed that the USAF favoured theside-by-side cockpit arrangement that wasoriginally proposed for the ATA Model-21.Finally, the RAF had expressed an interest ineventually buying land-based A-12s toreplace the Panavia Tornado GR4.

But when the cost of each A-12A reached$96.2 million in January 1990, it was clear that

Below left: Simulated image of an A-12A stealthattack aircraft in flight. McDonnell Douglas/Bill Rose Collection

Below right: An early proposal for the AdvancedTactical Aircraft (ATA) programme built as a testmodel. Many of the features seen here, such as theupturned wingtip fins and engine inlets, weredispensed with. General Dynamics

Bottom left: This twin-engine, low-observable strikeaircraft was a 1990s British Aerospace concept forthe UK's Future Offensive Strike Aircraft Project.It may have been directly based on a US designsuch as the unsuccessful Northrop ATA proposal.BAESystems

Bottom right: This artwork shows the possibleappearance of a scale-size, one-man proof-ofconcept demonstrator that preceded the A-12Avenger II. This aircraft may have been knownas the Model 100. Bill Rose Collection

all was not well with the programme and thesespiralling costs were accompanied by someserious ongoing technical difficulties. Of primary concern was the aircraft's weight whichhad steadily increased beyond the originalspecification. The extensive use of compositeshad not produced the anticipated weight savings and as a consequence some componentswere now being fabricated from lightweightalloys. There were also unresolved difficultieswith the advanced avionics and the state-ofthe-art synthetic aperture radar system.

The A-12A programme may have seemedunstoppable, but alarm bells were nowsounding in Washington and during April1990 the Secretary of Defense Dick Cheneyordered a major review. It emerged that apartfrom serious technical issues, the projectfaced a $2 billion over-run and the first flightwould be delayed until late 1991. The firsteight aircraft were already under construction at Tulsa and enough parts had been manufactured to complete a total of 14 aircraft.

Intense negotiations took place and the Navy

It is understood that the principal NorthropATA design was similar to a scaled-down B-2Abomber. However, the configuration shownin this drawing eventuaUy appeared as a USPatent (Des 342,717) that was published on28 December 1993 and is known to have beenwind tunnel tested in model form during theATA programme. Conceivably, this stealthydesign is close in appearance to one ofNorthrop's ATA proposals_ US Patent Office


This design for a twin-engine stealth bomberwas produced by Rockwell Internationalin the late 1970s. Generally referred to as theDelta Spanloader, a number of differentconfigurations were produced and some smallmodels were wind tunnel tested. The designreference for this series was 0-645.Bill Rose Collection

The Senior Peg programme began with Lockheed basing the design ofa new light-bomberon work undertaken during the Hopeless Diamond programme that had produced the

Senior Peg

US Manned Tailless Aircraft(1980-2030)

Chapter Five

was contracted to study a light-bomberunder a highly-classified programme calledSenior Peg and Northrop was asked to produce proposals for a more advancedstrategic nuclear bomber under the codename Senior Ice.

The Defense Advanced Rese?rch ProjectsAgency (DARPA) funded a series of highlyclassified studies in 1974 to examine newtechnologies that might give aircraft the ability to avoid detection by Soviet radar networks. The initial contractors who undertookthis work were Northrop and McDonnell Douglas with the programme being extended toinclude Lockheed in 1975. Following radartrials at White Sands, Lockheed and Northropreceived further USAF and DARPA funding tocontinue research.

In 1978, Rockwell International at LosAngeles, California, completed a major study(partly sponsored by the US Air Force) toexamine bomber needs for the 1990 to 2000period, taking note of stealth developments.Several new designs emerged from thisproject that included a forward-swept, twinengine, canard penetrator with supersonicperformance, a four-engine flying wingequipped with a rear-mounted (possiblyretractable) turret containing a defensivelaser weapon and a stealthy twin-enginedelta bomber, simply referred to as theSpanloader.

To fully exploit the latest developments instealth technology, the USAF partnered Rockwell with Lockheed while Northrop wasteamed up with Boeing and Vought. Bothgroups would design new low-observable aircraft and at the same time DARPA awardedNorthrop a contract to construct a 'one-offmanned stealth test-bed which was given thecodename Tacit Blue.

It was now clear to senior Pentagon officials that within a few years it would onlybe possible to penetrate Soviet air spacewith stealthy aircraft. Consequently, it wasdecided to develop a light bomber as quicklyas possible which utilised technologiesdeveloped by Lockheed during the HaveBlue programme. It was also accepted that amore ambitious stealth bomber was neededin the longer term. As a result, Lockheed

This four-engine flying wing concept was producedby Rockwell International, possibly within the late1970s 0-645 stealth bomber study. Note the turretcontaining a laser weapon mounted at the rear ofthe fuselage for self-defence. Bill Rose Collection(based on Rockwell artwork)

270ft 3in (21.4m)36ft 3in (I 1m)I,308ft' (I 22m')37ft 3in (I1.35m)11 ft 3in (304m)39,0001b (I 7,700kg)80,0001b (36,300kg)2xGeneral Electric F412-GE-D5F2non·afterburning turbofans, eachrated at 13,0001b (58kN)580mph (930kph)40,000ft (I2,200m)800nm (920 miles or 1,480krn)Amaximum of 15,000lb (6,803kg)bombs or ASMs. 2x (originally 4)AlM-9 AAMs or AIM·120 AdvancedMedium Range Air·to·Air Missiles(AMRAAM) and 2x High SpeedAnti-Radiation Missiles (HARM)

The General Dynamics/McDonnellDouglas A-12 Avenger IIconfigured with a side-by-sidecockpit arrangement. Initially,this was the favouredarrangement and it is believedthat the USAF opted for thisversion. Bill Rose Collection


CrewWingspan (unfolded)Wingspan (folded)Wing areaLengthHeightEmpty weightGross weightPowerplant

McDonnell Douglas/General DynamicsA-12 Avenger II

Early artwork showing the very clean triangularshaped A-12 in US Navy service. US Navy

have been persistent rumours that a smallbatch of production aircraft were completedby late 1995 and secretly supplied to theUSAF. If the USAF did take these A-12s, theymay have been considered for special deniable missions or optimised for use as lowobservable spyplanes. Another rumour concerns the secret development of anUnmanned Combat Aerial Vehicle (UCAV)for the USAF which was directly based on theA-12A. This mayor may not be true, but itcould be many years before all the details ofthis programme become public knowledge.

planned next-generation strike aircraft and thecontractors made efforts to rescue the deal byproviding a lower cost, stripped down versionof the A-12A. Northrop and Lockheed also submitted plans for suitable aircraft, but the Navywas reluctant to embark on any new projectswith an element of risk. Subsequently, it wasdecided to buy a larger, improved version ofthe F/A-18 known as the F/A-18E1F Super Hornet and wait to see how the Joint Strike Fighter(JSF) project progressed (later the LockheedF-35 Lightning II). Clearly, the Super Hornetwas never going to be a direct substitute forthe stealthy A-12A, but it remains a rugged andreliable combat aircraft which is capable ofundertaking a wide range of missions.

During the A-12A programme at least onefull-sized A-12A mock-up was built and there

This three-view drawing showsthe A-12 in its final form for theUS Navy. Bill Rose Collection

Intense negotiations took place and the Navymodified its contract to allow delivery of thefirst aircraft by the last day of 1991. But the contractors now insisted that it would be impossible to build the A-12A for the agreed price andsome estimates put the total cost of completing the programme at about $10 billion. On 7January 1991, Cheney announced that the A-12programme had been cancelled and cited rising costs and unacceptable delays. Just under$3 billion had been spent on the A-12A and thegovernment wanted some of its money back.This led to a major legal dispute between General Dynamics, McDonnell Douglas (later Boeing) and the Department of Defense that wouldroll-on into the 21st century.

With the shock cancellation of the A-12Aprogramme, the Navy was left without its

108 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (J980-2030j 109

Lockheed CL-2102-2 Low Level Penetrator

DRY F101 ENGINES

FLUSH 2-D NOZZLESBELOW WING

IIII

)

COMPOSITE MATERIALS

aircraft, which would be upgraded to fullspecification with the first examples enteringservice during 1987.

A DARPA illustration for a low-altitude stealthbomber that was considered during an early stageof what became the Advanced Technology BomberCATB) programme in the early 1980s. DARPA

USAF artwork released into the public domainduring the 1980s which depicted the forthcomingB-2 bomber. Although some of the details such asengine exhausts were not revealed, this image wasreasonably accurate and reflects acceptance thatthis high-profile aircraft would eventually becomeimpossible to hide. USAF

LOW ALTITUDE CONCEPT

CANTED VERT.TAILS BELOW WING

SHARP LEADING EDGELOW FREQ. RAM

new strategic bomber, receiving a development contract on 4 December 1981. By thetime this contract was signed, the existence ofan advanced bomber programme had beenpublic knowledge for about a year andNorthrop now began a major engineeringdevelopment review that would last until June1983.

The aircraft was assigned the nameAdvanced Technology Bomber (ATB),although the programme was officiallyknown as Senior Cejay. The Reagan Administration planned to eventually have 127 ATBsin USAF service, plus the five initial evaluation

The Northrop high-altitude proposal codenamed Senior Ice was a flying wing that isclearly recognisable as an early incamation ofthe B-2A bomber. Project Director HalMarkarian was directly responsible for theSenior Ice programme and he reporteddirectly to Welko E. Gasich who was theSenior Vice-President for Advanced Projects.Contrary to some opinion, this design was nota development of the earlier Northrop YB-49or heavily-influenced by the wartime HortenHo IX and its appearance was initially dictated by complex calculations to achieve thelowest possible radar-cross-section within anoperational environment. Secondary considerations were the use of new materials and asophisticated flight management system.However, the study was enlarged in early198 I to include concepts for low-level missions. This branch of the project remainslargely classified, although Northrop mayhave worked on a tailless triangular design forthis role which was the subject of a DARPAstudy.

Although this design was very different tothe Skunk Works low-altitude penetrator, itwas conceived (like the Lockheed CL-2120-2)to fly the last part ofa strike mission at altitudeof about 200ft (61 m) and speeds in the regionof Mach 0.7. But either the cost of operatingtwo different types of aircraft was prohibitiveor there were too many unforeseen technicalchallenges. Stability control was considered amajor issue for a stealth aircraft operating attreetop height and afterburners wereregarded as essential to meet take-offrequirements. So it was finally determinedthat the most cost effective solution was toproceed with the high-altitude design andintroduce a modified low-level version of thisaircraft if the need should arise.

Nevertheless, as something of a compromise, President Reagan authorised the construction of 100 B-1 B bombers on 2 October1981 which were modified variants of theoriginal supersonic variable-geometry B-1.This version was quite stealthy, but the lowerradar cross-section came with a performancepenalty. Nevertheless, the B-1 B was capableof being flown at almost the speed of soundjust 500ft (152m) above the ground. Lockheedwas regarded as the leading exponents ofstealth technology and its partner Rockwellhad developed the B-1 bomber, so the industry expected them to win this competitionand envisaged the Northrop design beingplaced on the back burner. But surprisingly,the USAF rejected Senior Peg and Northropwas selected on 17 October 1981 to build the

Senior Ice

100ft (30m) estimated'55' (leading edge)76ft (23m) estimated*Unknown2xafterbuming turbofan enginesproviding a total of 60,000 Ib thrust.The engines would utilise noisereduction measures and twodimensional AsymmetricLoad-Balanced Exhaust Nozzles(ALBEN)412,000 Ib (l86,880kg)Unknown but subsonicUnknownUnknown50,0001b (22,679kg) bombs andmissiles. The possibility of carryinga defensive laser weapon mayhave been considered, if thetechnology became available

• Figure from a reliable source, but not definitive.

Gross weightMaximum speedCeilingRangeArmament

Rockwell D645-4A Stealth Delta Spanloader

Armament

4183ft 4in (56m)205ft (62.4m)7,278ft' (676m2

)

7,528ft' (699m')45' (leading edge)3.0G4.625.5899.7ft (30.38m)25.75ft (7.84m)l45,2401b (65,879kg)526,1401b (238,653kg)4xturbofan engines. Possiblyafterbuming.

Maximum speed Mach 0.80Ceiling 50,000ft (l5,240m)Optimised for operations at 200ft (6Im)Range (un-refuelled) 5,753 miles (9,260km), with 2,300

miles (3,700km) flow at low-level40,0001b (l8,143kg) payload

CrewWingspanWingspan (tips down)Wing areaWing area (tips down)SweepLoad factorAspect ratio

(tips down)LengthHeightEmpty weightGross weightPowerplant

Two designs from the Lockheed Skunk Works thatare believed to have fallen within the Senior Pegprogramme for a new advanced bomber utilisingstealth technology. The top drawing has thecompany reference CL-2120-2 and was optimisedfor very low-level operations. The bottom drawingis based on information from several sources,which is thought to show Lockheed's proposal fora high-altitude stealth bomber. It remains unclearif this development work was utilised for anyfurther projects that remain within the blackdomain. Bill Rose Collection

WingspanSweepLengthHeightPowerplant

Lockheed assigned a company referenceCL-2120 to the study and it has been possibleto find some details of CL-2 I 20-2. This was aflying wing with a leading edge sweep ofabout 45° that was optimised to fly at altitudesin the region of 200ft (60m). Several possibilities were considered for central stabilisersand the aircraft would have been equippedwith movable wingtip fins with rudders.Propulsion took the form of four deeplyburied turbofan engines with stealthy leadingedge intakes located on each side of thecockpit and carefully configured rectangularexhaust outlets at the centre of the trailingedge. The wingspan was 183ft 4in (56m),which could be increased to 205ft (62.4m) bylowering the wingtips during a fully ladentake-off. Length of the CL-21 02-2 was 99ft 8in(30.38m) and height 25ft 8~in (7.84m). Empty,the aircraft was expected to weigh 145,240 Ib(65,879kg) and gross weight was estimated at526, I 40 Ib (238,653kg), including a 40,0001b(l8,143kg) payload. Maximum speed at verylow altitude was Mach 0.6-0.7 with a serviceceiling of about 50,000ft (l5,240m). Maximum un-refuelled range was expected to be5,753 miles (9,260km) with 2,300 miles(3,700km) flown at low-level during an attackmission.

/

(L-- ....

F-117A stealth interdictor. Most of the detailsremain secret, but it is believed that the earlySenior Peg studies resulted in several fourengine aircraft conc:epts roughly in the classof the F-111. In appearance, these designswere almost flying wings with flat undersidesand faceted upper surfaces. lt is also reportedthat Lockheed favoured a narrow tail sectionfitted with two V-shaped stabilising fins.Although USAF interest shifted towards theNorthrop proposal, it has been suggested thatLockheed may have studied a strategicbomber with a wingspan in the region of 170180ft (50-55m), perhaps loosely based on theRockwell Spanloader. Built mainly from composite materials, this aircraft would havebeen manned by a crew of three.

Little is presently known about the SeniorPeg proposals, but the Skunk Works later produced designs for a strategic stealth bomberspecifically optimised for low-level penetration. This came about in late 1980 when concerns were expressed within the USAF thatSoviet defences would eventually be capableof detecting and tracking high-altitude stealthbombers and a low-level option was neededas a fallback.

Whether or not this design work was part ofthe Senior Peg project remains unknown, but

110 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (1980-2030) 111

Northrop B-2A

The ATB was officially renamed as the B-2A inSeptember 1984 and security at Northropand the sub-contractors remained oppressive. In addition to intrusive surveillancemethods, large numbers of Northrop workersat the Pico Rivera B-2 plant and Palmdalewere made to undergo polygraph tests. Falsecompanies were established to receive B-2components which were delivered by subcontractors, computers were isolated withinscreened enclosures to prevent electronic

eavesdropping and USAF top brass whovisited the plant always arrived in civilianclothing.

While the new bomber was still in thedevelopment phase, the strange-lookingTacit Blue low-speed technology demonstrator was undergoing secret tests at Groom DryLake and it would remain classified until1996. Described initially as an experimentalreconnaissance platform, this compact 55ftlOin (17m) long aircraft, which looked like aninverted bathtub with stubby wings, was usedto develop various technologies that would

This image is directly based on USAF artworkreleased in the early 1980s that allegedly showedan early proposal for the Advanced TechnologyBomber (ATB). Many experts dismissed thisconcept as unlikely to bear any resemblance to thenew bomber. However, it may have been partlyderived from one of the Rockwell Delta Spanloaderdesigns or a proposed low-level penetrator,finished with an experimental camouflage finishintended for this role. Bill Rose Collection

find their way into the B-2A. However, TacitBlue bore almost no resemblance to the B-2Aapart from perhaps the cockpit canopy and itis believed that Tacit Blue was also used todevelop the AGM-137 TSSAM (Tri-ServiceStandoff Attack Missile). While there is noproof or admission that prototypes were builtduring the B-2A programme, there were reliable reports of small flying wings beingsighted in areas associated with secret aircraft trials that hint at the possibility.

On 22 November 1988, the first B-2A (AV-I)was unveiled at Northrop's Palmdale facilityin California. Many aspects of the programmeremained secret, but it was felt that keepingthe B-2A under wraps any longer would raisetoo many unnecessary problems and serveno useful purpose. Attending this ceremonywere USAF officials and members of themedia, with access to the aircraft carefullyrestricted to avoid anyone seeing sensitiveareas such as the engine exhausts. But areporter called Michael A. Dornheim was onestep ahead of these measures and flew a lightplane over the facility with a photographeronboard. Nobody had considered this possibility and it led to a major scoop whichshowed many of the aircraft's features thatNorthrop and the Air Force would have preferred to remain under wraps.

AV-l undertook its first test flight on 17 July1989 at Palmdale, flown by Northrop's TestPilot Bruce Hinds and USAF Col RichardCouch. The second aircraft (AV-2) would flyjust over a year later. At this time, the USAFconfidently anticipated paying $550 millionfor each new B-2A that rolled off the production line. Amazingly, this had risen to $865million by 1991 and when the developmentcosts were added, the price of each aircraftwas closer to that of a space shuttle at morethan $2 billion. This spiralling price tag wouldsoon lead to widespread political criticismand allegations of wrongdoing.

A side-by-side comparison between the NorthropB-49 bomber (top) and the modern NorthropGrumman B-2A Spirit stealth bomber. Theseaircraft are approximately to scale and thepurpose of this drawing is to show that the B-2Ahas almost nothing in common with the originalNorthrop flying wing bomber. Bill Rose Collection

A B-2A Spirit bomber crossing rugged desertterrain. USAF

B-2A Spirit ofMississippi which was delivered tothe USAF in 1993 and has since been upgradedto Block 30 specification. USAF

A B-2A of the 509th Bomb Wing at Whiteman AFBin Missouri. USAF

On 1 March 1990, the Washington Postreported that Northrop admitted in court to 34counts of overcharging the Government during development of the B-2A. While a further141 charges were dropped, Northrop endedup with a record fine of $1 7 million. Evidently,there was - and may still be - plenty of scopefor misappropriation of funds within a highlyclassified big budget project. There were alsoreports that the B-2A's range and payloadcapability was somewhat less than anticipated and the aircraft remained visible toradar systems in certain conditions. In 1991,the USAF admitted that tests had revealedvarious weaknesses in the B-2A's ability toavoid detection and steps had been taken tocorrect the problem with the application ofmore RAM in some areas. This soundedworse that it probably was because stealthtechnology is hardly perfect and does havelimitations.

The first production B-2A Spirit (AV-8) wasaccepted into USAF service on 17 December1993 at Whiteman AFB, Missouri, and therecan be little doubt that the B-2A is anextremely sophisticated and potent aircraft. Itis ideal for special operations using conventional or nuclear weapons and has a far superior delivery performance to the B-1 B. Just sixaircraft could have undertaken the entire1986 attack on Libya, operating from the USmainland. Many new cutting-edge processeswere employed for the construction of thisaircraft with components manufactured fromaluminium and titanium alloys, steel andcomposites. A special elastomeric coatingwas developed for the aircraft's exterior, tomaintain uniform conductivity and avoidradar hot spots at seams.

Northrop was responsible for producingthe forward body, cockpit, leading and trailing edges and control surfaces. Boeing manufactured most of the remainder of the B-2Awith Ling-Temco-Vought providing components for the wing and engine intakes/exhausts. Each aircraft was to be completedat Palmdale, California, before delivery to theUSAF. Because the aircraft is inherentlyunstable, the Digital Flight Control System(DFCS) is the B-2A's most important piece ofequipment. Using a quadruplex fly-by-wiresystem, the DFCS manages a series of control

112 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (J 980-2030) 113

• 2

surfaces located along the trailing edge. Thisincludes two sets of combined brake-rudderstowards the wingtips that control yaw, twothree-part sets of elevons and the Gust LoadAlleviation System (GLAS) located at the rearof the centre line which is mainly used to control pitch. It is also thought that yaw can becontrolled in certain situations by varying portor starboard engine thrust.

The B-2A has a wingspan of 172ft (52.42m)making it similar in size to the originalNorthrop flying wing bombers. The overalllength is 69ft (21m) and the aircraft's height is17ft (5.18m). Empty, the B-2A weighs about153,7001b (69,717kg) and the maximum takeoff weight is 376,0001b (l70,550kg). Propulsion is provided by four non-afterburningGeneral Electric F-118-GE-IOO turbofanengines each rated at 17,300 Ib (77kN) staticthrust which allows a maximum speed ofMach 0.95, a ceiling of 50,000ft (l5,240m) andan un-refuelled range in excess of 6,000 miles(9,600km) carrying a 37,300 Ib (l5,920kg) payload. A wide range of conventional andnuclear free fall or guided weapons can becarried by the B-2A. The maximum weaponspayload is quoted as 49,3171b (22,369kg).A later Block 30 upgrade known as theGeneric Weapons Interface System (GWIS)would allow the B-2A to carry different mixesof weapons making it possible to attack asmany as four different targets during a singlemission.

The B-2A was originally equipped with theRaytheon AN/APQ-181 covert strike radaroperating at the J band. This is a very sophisticated multi-function radar system that couldbe used for terrain following and hazardavoidance at low altitude. Significant andcostly upgrades to the B-2A's radar systemhave been undertaken in recent years withthe installation of several classified modulesand a new Active Electronically Scanned

A full load of conventional free-fall bombs isreleased by a B-2A during trials. USAF

A Mk84 2,000 Ib bomb about to be loaded into aB-2 Spirit bomber at Andersen AFB, Guam. USAF

The Joint Direct Attack Munition (JDAM) is a familyof cost-effective and highly accurate weapons thatcan be carried by a number of US and Europeanmilitary warplanes. This photograph shows aGBU-31 JDAM bomb during transport to awarplane. JDAMs have been used by a number ofUS aircraft during several recent conflicts. TheB-2A made its combat debut during OperationAllied Force in 1999, delivering more than 650JDAMs to Serbian targets. The most controversialB-2A mission involving JDAMs was the 'accidental'bombing of the Chinese embassy in Belgrade on7 May 1999 when three JDAMs hit sensitive partsof the building. USAF

An inert practice B-61 nuclear weapon is releasedfrom a B-2A at the Tonopah Test Range in Nevadaon 20 November 1996. USAF

A B-2A refuels from a KC-135 tanker above thePacific Ocean while flying to Andersen AFB, Guam.The unusual shape of the aircraft in thisphotograph is caused by the use of a fisheye lens.USAF

A Northrop Grumman B-2A in flight. USAF

Array (AESA) antenna. No defensive armament is carried by the B-2A which relies on itsability to hide from radar. But having said that,each B-2A is equipped with a Defensive Management Subsystem (OMS). This includes theLockheed Martin AN/APR-50 (also known asthe ZSR-63) radar warning system thatdetects and identifies threats. It is thoughtthat this equipment may have the ability tocancel out radar returns. Honeywell andRaytheon have provided other classifiedcomponents of the OMS, but their functionsare unknown. Normally, a crew of two fly thisaircraft, but there is provision for a third member who may be required for certain specialised missions.

By the mid-1990s, there was growing opposition within Congress to the very expensiveB-2A programme and an amendment to the1997 Defense Authorisation Bill was tabled tocap production of the B-2A at 21 aircraft.Although this proposal was narrowlydefeated, it was not just Congress which wasconcerned about costs, but the USAF whofeared that procurement of further stealthbombers would mean severe funding restrictions in other areas. As a result, Congressnever approved the construction of furtherB-2As and three optional aircraft (AV-22-76,AV-77-133, AV-134-165) belonging to the initial batch were cancelled.

Military OperationsThe B-2A was used in combat for the first timeon 24 March 1999 when two aircraft deliveredprecision-guided munitions to targets inYugoslavia. The objective of this NATO campaign was to secure the withdrawal ofSerbianmilitary, paramilitary and police forces fromKosovo by means of a substantial air attack onthe Serbian military and civilian infrastructure.Known as Operation 'Allied Force', the raidslasted until II June 1999 and during this timesix different B-2A aircraft flew 45 long-rangemissions from the USA. Typically, each flightwould last for 30 hours and in total the B-2Asdelivered 656 Joint Defence Air Munition(JDAM) bombs to Serbian targets.

Unquestionably, the most controversialmission involving a B-2A during this cam-

114 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (J980-2030) 115

Northrop-Grumman B-2A SpiritStealth Bomber

A Northrop Grumman B-2A returning from amission during Operation Iraqi Freedom on27 March 2003. USAF

EvolutionRecent improvements to the B-2A fleetinclude the Link 16 aircraft-to-aircraft datatransmission system, the introduction of a virtually unjammable EHF (Extremely High Frequency) satellite connection, a digital enginecontrol system to replace the troublesomeanalogue controllers and the capability toattack moving targets with precision-guidedweapons.

Since the aircraft's introduction, there havebeen proposals for new or modified versions.One possibility considered was the installation ofa multi-role sensor package that wouldresult in the aircraft being redesignated as theRB-2A. Another suggestion was a SignalsIntelligence (SIGINT) variant called theEB-2A. A further proposal was to turn the B-2fleet into remotely piloted vehicles capable ofrefuelling automatically and carrying muchlarger payloads. It is likely there was considerable resistance to the idea of convertingsuch an expensive warplane into anunmanned vehicle and equally probable thatdependable technology to allow such a thingwas lacking when the idea first surfaced. Atthe start of the 21st century, there was considerable interest in the idea of producing asecond batch of 40 B-2 bombers to meetUSAF needs. This would have resulted in amodified design known as the B-2C. The 'C'reference would stand for conventional, indicating it was not specifically designed todeliver nuclear weapons. The exact differences from the B-2A remain unclear, but theB-2C was described as 'improved'.

In 2001, Northrop-Grumman suggestedthat production could be restarted for about$3 billion, with each aircraft costing $735 million, but Northrop's Pico Rivera facility wherethe production of B-2A aircraft began hadbeen closed down, so this meant that Boeingwould undertake most of the work. Both theVice President Dick Cheney and Defense Secretary Donald Rumsfeld were in favour of proceeding with this option, but there wasconsiderable political opposition and eventually the plan was abandoned.

tain Wilson, who had already flown B-1 Bsduring Operation Allied Force.

No B-2As were lost or reported damagedduring the 2003 Iraq campaign. Enemy airdefences proved largely ineffective and theIraqi Air Force are not thought to have operated any fighter aircraft during this period. Inaddition to the B-2A being flown by womenon combat missions, RAF Squadron LeaderDavid Arthurton became the first foreign pilotto fly the B-2A in 2006 while participating inthe Personnel Exchange Program.

was based on the suggestion that Iraq wascontinuing to develop weapons of massdestruction which threatened regional stability. As a prequel to operations, 20 members ofthe USAF's 49th Material Squadron arrived atDiego Garcia during December 2002 andorganised the assembly of two huge portableshelters for B-2A bombers.

The task took 70 days to complete and itwas the first time these sophisticated unitswith their high-tech environmental systemshad been used operationally. Each fully airconditioned shelter measured 55ft (l6.76m)in height and 250ft (76m) wide. Each shelterwas shipped by air to the operational site insections requiring 29 C-130 Hercules flights.With the ability to undertake some B-2A missions from Diego Garcia, the strike distance toBaghdad could be reduced to less than halfthat from Whiteman AFB, Missouri.

From early in the campaign, B-2As attackedkey Iraqi targets with JDAM munitions andthese aircraft were often used to take out Iraqiradar and communications facilities.Although combat missions with the mostadvanced US warplanes are generallyregarded as a male preserve, Capt JenniferWilson, who was stationed with the 393rdExpeditionary Bomb Squadron at Diego Garcia, became the first woman to fly a B-2Aoperationally on I April 2003. But this was notthe first combat mission for 30-year-old Cap-

USAF Capt Jennifer Wilson, who became the firstwoman to fly the B-2A operationally on I April 2003during the Iraq conflict. USAF

buildings that were marked for avoidanceby NATO warplanes and it seems veryunlikely that the strike was an accident. It waslater claimed that the intended target hadbeen the headquarters of the YugoslavFederal Directorate for Supply and Procurement (FDSP), but few observers believed thisto be true. There are several possible reasonsfor the attack and it has been suggestedthat the Chinese embassy was being used torelay radio messages to irregular forces underthe direction of the late Zeljko Raznatovic(usually known as Arkan). This is a possibility,but it's more likely that Chinese intelligencewere monitoring NATO operations and testing advanced passive detection equipmentcapable of tracking stealth aircraft. Perhapsthey were passing immediate details to theSerbs?

On 27 March 1999, a F-117A stealth aircraftwas shot down near the village of Budjanovciin Serbia and in a separate incident a F-117Ais understood to have returned to base badlydamaged. Conceivably both events resultedfrom newly-developed methods of detection.There may also be a link to the destruction ofBelgrade's RTS television station on 23 April1999 by two Tomahawk cruise missiles. Thisreportedly killed 16 people and injured 20.NATO refused to apologise for the attack,claiming the station was broadcasting unacceptable propaganda. But the TV transmitter's powerful output may have been assistingpassive stealth detection technology controlled from the embassy.

When the embassy raid took place thebuilding was largely empty, but three personnel were killed, 20 were injured and therewas substantial damage. Chinese PresidentJiang Zemin expressed outrage at the attackand relations with America were strained forsome time. The US administration apologisedto China, eventually paying $28 million incompensation, but it could be decadesbefore the truth emerges about this incident.

Following the events of II September 200 I,it was determined that Osama bin Laden wasresponsible for organising the attacks onAmerican targets. The CIA was confident thathe was hiding in Afghanistan and Washingtoninsisted that the Taliban government handover bin Laden and the al·Qaeda leadership.They refused and a major military operationbegan initially involving air power.

B-2As were used on three consecutive daysto strike al-Qaeda and Taliban positions inAfghanistan with stopovers at the British baseat Diego Garcia in the Indian Ocean. The nextoperational use of the B-2A would take placeduring the second GulfWar (or Iraq War) thatbegan in March 2003. This US-led campaign

2with provision for 3rd member172ft (52.42m)5,140ft' (478m')69ft (21m)17ft (5.18m)153,7001b (69,717kg)336,5001b (I 52,635kg)376,0001b (l70,550kg)4xnon-afterbuming GeneralElectric F·118·GE·IOO turbofanengines, each rated at 17,300 Ib(77kN) static thrustMach 0.95, approx 570mph(915km/h) at sea level50,000n (l5,240m)Nuclear strike mission with mix of16 AGM-129JB61 weapons(weighing 37,300 Ib - 15,920kg)6,330 miles (10, 186km).Similar Mission with Ix refuelling:11,508 miles (18,529km)40,0001b (18, I44kg)49,3171b (22,369kg)

Normal payloadMax weapons loadArmament(Carried by 2Boeing Rotary Launcher Assemblies in eachbomb bay): AGM·129 ACM W80 Nuclear Warhead;AGM-131 SRAM 2W89 Nuclear Warhead; AGM-137 TSSAMHE or submunitions; AGM-154 JSOW submunitions; B61Nuclear Penetrator; B83 Nuclear Variable Yield; BLU-118/BThermobaric Weapon; Mk64 2,000 Ib (907kg) Sea Mine;Mk82 500lb (226kg) HE Bomb; Mk83 1,000 Ib (453kg) HEBomb; Mk84 2,000 Ib (907kg) HE Bomb; CBU·87 Cluster;CBU·89 Cluster; CBU·97 Cluster; GBU·27 Paveway III2,0001b (900kg) HE Laser Guided EGBU-27 Enhancedversion ofGBU-27, with additional GPS guidance; GBU·31/2JDAM Mk83/84 HE or BLU·109 Penetrator Warhead; GBU·374,7001b (2,13Ikg) Penetrator

Maximum speed

CeilingRange

These portable B-2 shelters were assembled atDiego Garcia by the USAF's 49th MaterialSquadron. USAF

CrewWingspanWing areaLengthHeightEmpty weightTake·off weightMax take-off weightPowerplant

Demonstrating its true global capability, Spirit ofMissouri prepares to touch down at Whiteman AFBafter flying a long-range mission to Iraq. USAF

paign took place on 7 May 1999 when asingle B-2A escorted by EA-6B Prowlers andF-15C fighters dropped three JDAM bombs onthe Chinese embassy in the Novi Beograddistrict of Belgrade. President Bill Clintonand CIA director George J. Tenet both insistedthat the bombing had been a terrible accidentdue to the use of an outdated map. However,the Chinese embassy was one of many


Russian DesignsSoviet designers studied US stealth development in great detail and it has been a topic ofoccasional discussion that a Russian equivalent was never built. In fact, there was a Myasishchev project conducted during the 1980sto develop a high-altitude spyplane bearingthe codename M-67, which produced at leastone manned proposal that vaguely resembledthe B-2A (see Chapter Six). Whether or not thisdesign came about as the result of informationgathered by Soviet Intelligence is unknown. Inearly 1996, the MiG Design Bureau releasedartwork of a canard-shaped stealth bomberthat loosely resembled the B-2A. The drawingis certainly interesting, but Russia was nolonger in a position to fund such an expensiveprogramme and the MiG stealth bomber wasclearly little more than wishful thinking.

Chinese Stealth BomberAccording to some recent reports circulatingin the Far East, China has been working on anadvanced stealth strike aircraft known as theXian H-8. Apparently, the H-8 project was initiated in 1994 with the aim of equalling America's B-2A bomber. Said to possess marginalsupersonic performance, an intercontinentalrange and the ability to carry advancedweapons, it has been claimed that the H-8 isabout to enter production. Illustrations ofunknown origin suggest that the H-8 is a compact, highly swept flying wing, possibly powered by two deeply recessed engines.Nobody would deny that the Chinese havemade huge technological strides in recentyears, but there seems little likelihood that awarplane with this capability is about to enterservice or even exists.

B-2ALossThe B-2A has a good record of safety with theloss of only one aircraft since its introductioninto service. This accident took place at Andersen AFB, Guam, on 23 February 2008 whenB-2A (AV-12 Spirit of Kansas) was taking off.The crew believed that the aircraft had reachedtake-off speed, when it was actually travellinglOkts (11.5mph or 18.5kph) slower. The problem was caused by moisture in three of the 24air pressure sensors providing incorrect information to the flight computer. This reportedthat the aircraft was in a nose down positionand required a 300 pitch change, leading to astall. Consequently, the aircraft swerved off therunway and as the left wingtip hit the groundMajor Ryan Link and Captain Justin Grieveejected. Both were injured with Grieve suffering some compression fractures to his spine.The aircraft was a complete write-off.

Left: It is now clear that Russian scientists andengineers studied US stealth developments ingreat detail. Many western observers expectedRussia to match the Northrop Grumman B-2Awith a similarly specified bomber, but this neverhappened, perhaps due in part to the high costand deteriorating Soviet economy. The only hint ofsuch a possibility was in early 1996 when the MiGDesign Bureau released artwork of canard stealthbomber vaguely resembling the B-2A. However,Russia was not in a position to develop such anexpensive aircraft and it remains unlikely. Thisillustration has been developed from the originalartwork as a representation of the MiG design.Bill Rose Collection

Below left: This poor quality image, lifted fromvideo footage, shows the moment when Spirit ofKansas ran into serious trouble during take-off atAndersen AFB, Guam, in February 2008. The crewwere forced to eject and the aircraft wasdestroyed. USAF

Below: Wreckage of the B-2A that crashed duringtake-off at Andersen AFB, Guam. Smoke continuesto issue from the aircraft, which was a total writeoff. The cause of the accident was moisture inthree of the 24 air pressure sensors that supplydata to the flight computer. USAF

Senior Citizen

On 24 April 1980, the United States undertooka daring multi-services covert mission to rescue 52 hostages being held at the US Embassyin Tehran, Iran. Known as 'Eagle Claw', theoperation degenerated into a total disaster.Retired Chief of Naval Operations Adm JamesL. Holloway III was given the task of headingan official investigation which found majordeficiencies in planning and co-ordination.While the failure of 'Eagle Claw' cannot beblamed on the aircraft used, it highlighted thefact that some Special Forces operationswould benefit from transporters possessing ahelicopter's VTOL ability and the speed, rangeand payload capability of a fixed wing aircraft.

An aircraft of this type was the dream ofaeronautical designers for decades with German engineers at Focke Achgelis making aserious effort to develop just such a 'convertiplane' during World War 2. This design,which combined aspects of the helicopterand fixed wing aircraft, was never completed,but Bell saw the tilt-rotor's potential duringthe early post-war years and it led to theexperimental XV-3 which first flew in 1955.This research project would eventually resultin the Bell Helicopter Textron and BoeingHelicopters V-22 Osprey which took atremendous effort to develop and was almostcancelled on several occasions due to serious accidents and rising costs.

Today, this unique aircraft is in service withthe US Marine Corps and the USAF, so shoulda similar situation to the Iranian hostage crisisarise, there is every possibility that the Ospreywould be used. It can carry at least 24 soldiersand their equipment with a combat radius of428 miles (690km) that can be extended within-flight refuelling. The Osprey can cruise atabout 316mph (508kph), well above thereach of small-arms fire or shoulderlaunched missiles. As SUCh, it appears wellsuited to Special Forces operations, medevacand the recovery of downed pilots in hostileterritory. Unfortunately, the Osprey remainsan imperfect design. Aside from the sheerengineering complexity of this aircraft, thereare some doubts about the Osprey's ability tosurvive in a harsh combat environment andthe huge 38ft (11.6m) diameter rotors makethe aircraft far from stealthy.

'Eagle Claw' spurred the Department ofDefense (DoD) to initiate full development ofthe V-22 Osprey in 1981 which was then knownas the Joint-service Vertical take-off/IandingExperimental (JYX) aircraft. However, therewas already major interest in low-observableaircraft and the idea of a larger, faster stealthytransport aircraft with STOL or ideally a VTOL

capability seems to have caught the attentionof senior officials at the Pentagon.

A series of highly-classified studies wasundertaken by the major aerospace contractors to design an aircraft to meet specifications for a stealthy tactical transporter.Nothing reached the public domain aboutthese proposals, but a Department of Defensedocument DoD7045.7-H, 'FYDP ProgramStructure', October 1993, would eventuallycome to light and it mentioned a projectcalled Senior Citizen, Program Element0401316F. The codename was initiallybelieved to refer to a hypersonic spyplaneproject, but was then identified as a stealthytactical transport aircraft.

Some design work undertaken at WrightPatterson AFB (probably in the 1980s) hadsuggested two favourable approaches to liftpropulsion for a VTOL special operations aircraft. The first way of generating lift was theuse of additional upright turbojets, while thesecond was to use large shaft-driven fans inducts. Although these ideas were hardly new,this work provided a useful framework for theSenior Citizen programme which isrumoured to have considered many differentconcepts including lighter-than-air designs.

One participant in the Senior Citizen project is understood to have been Northropwhich is thought to have proposed a designloosely based on the B-2A Spirit bomber. Thecentral section of the aircraft is presumed tohave similarities with the B-2, while the overall appearance is manta-shaped with clippedwingtips. Lift and hover would be achieved bythe use of four vertical ducts containing largeconstant RPM fans covered by shutters andlouvers during normal flight. Propulsiondetails of this study are unclear, but horizontal flight would be achieved using two or fourdeeply-buried turbofans and the aircraft

A US Marine Corps crew prepares a V-22 Ospreyfor night operations in Central Iraq during early2008. This aircraft is well suited to specialmissions, although it lacks the ability to hide fromenemy forces. US Navy photo by Chief Petty OfficerJoe Kane.

would be capable of making conventionaltake-offs and landings.

Details of what appear to be altemativedesigns from Boeing and/or Lockheed suggestan aircraft with semi-arrowhead shape usingengines for horizontal flight in a rear dorsalduct and two vertical stabilising fins on eitherside towards the rear wing area. Two banks offour upright turbojets are positioned on eachside of the fuselage. These provide lift andwould be covered by shutters during horizontal flight. Aclearer idea ofwhat may have beenunder consideration for the Senior Citizen programme can be found by studying a Lockheedpropulsion system patent (5,320305) filed on22 July 1992 and published two years later.

A small team at the Skunk Works, headedby the Chief Engineer of Advanced Development Projects, Dr Leland Malcolm Nicolai,produced this interesting concept thatappears to be specifically developed as astealthy flying wing aircraft. The propulsionsystem comprises two ducted cruise fans forhorizontal flight which are buried within thefuselage. Intakes for the engines are positioned towards the centre of the leading edgeand there are two-dimensional exhaust outlets at the centre of wing's trailing edge. TheVTOL capability is provided by two substantial, constant RPM ducted fans which are driven by two (or possibly four) engines locatedbetween both units with cross shafting toallow power redistribution in an emergency.To balance and control pitch during take-off,landing, hover and flight transition, air from


the cruise engine's bypass ducts would bediverted to forward and aft nozzles. To controldownward thrust, each fan would have variable pitch propellers. Each fan duct would befitted with covers on the upper side and louvered shutters on the wing's underside whichwould be adjustable for directional control.

At take-off, all engines would be operatingand the wing fan ducts would be fully open.Having left the ground, the lower louverswould slowly move rearwards and once theaircraft had reached sufficient speed to provide lift, there would be a full transition to horizontal flight with the cruise fans taking overand the fans shutting down and the coversclosing. Landing would be a reverse of thisprocedure. This propulsion system seems tobe completely tied into the flying wing designwhich would probably differ considerablyfrom the patent drawings. However, this verystealthy design has no vertical surfaces anduses ailerons, elevators and drag rudders forflight control. It is also shown with a multiwheel tricycle undercarriage.

Whether or not a Senior Citizen design hasbeen prototyped by one of the major contractors or even built as a small batch of specialops aircraft is impossible to say. But occasional sightings of unidentified triangularshaped aircraft by the public may (in a fewreliable cases) indicate that small numbers ofstealthy transporters exist and might be available for a high-priority clandestine mission.Such an aircraft would probably be able tocarry 30-35 soldiers with their equipment. Itwould be capable of in-flight refuelling andhave an operational range of about 2,500miles (4,000km). Depending on the propulsion system, the maximum speed might besomewhat better than the V-22 with a ceilingof perhaps 35,000ft (I0,668m) which assumesa fully pressurised cabin. Another possibility isa stealthy gunship variant. This might lack theVTOL capability but could be heavily armedand perhaps equipped with a chemical laserweapon for use against ground targets.

This drawing taken from a US Patent shows aLockheed VIOL aircraft proposal that may berelated to black budget 'Senior Citizen' project todevelop a stealthy theatre transport aircraft forhigh-risk covert Special Forces operations.Bill Rose Collection/US Patent Office

The unusual ducted and lift-fan propulsion systemfor a Lockheed VIOL stealth aircraft design.Bill Rose Collection/US Patent Office

Based on a number of different sources, this maybe the general appearance of a Boeing design for astealthy special operations transport aircraft with afull VIOL capability. Derived in part from the B-2Abomber, it is not know if this project progressedbeyond initial studies. Bill Rose Collection

Next Generation Bomber B-3

The Pentagon currently plans to keep theB-52, the B-1 B and the B-2A in service until2037 with the already ancient B-52 perhapsremaining operational until 2045. These'Legacy Bombers' will be subject to an ongoing programme of improvements until theirretirement. There are plans to supplementthe Legacy Bombers with an unmannedstrike aircraft, but a new manned strategicstrike aircraft is needed and the USAF wouldlike to see this reaching operational status by2018. The new bomber must be capable ofhandling any air defence system currentlyenvisaged. It will be subsonic, possess intercontinental range and have the ability todeliver a significant conventional or nuclearpayload.

While it has been suggested that the nextmanned US bomber should be a cutting-edgedesign capable of high supersonic speed, thePentagon is not prepared to initiate anotherfinancially challenging A-12A or B-2A programme. So this aircraft must be available inthe short term, affordable and effective as awarplane. Two teams of contractors havenow been chosen to develop detailed proposals for this project which is currentlyknown as the Next-Generation Bomber(NGB). Significant funding for NGB development is expected to become available shortlyand the contractors hoping to win this contestare Northrop-Grumman and Lockheed-Martin which have teamed up with Boeing.

Both groups are thought to be drawingheavily on experience gained withunmanned aircraft programmes for this project. Northrop-Grumman have been responsible for the X-47B Pegasus UninhabitedCombat Air Vehicle (UCAV) programme

Northrop Grumman's initial Next GenerationBomber proposal. The chosen design is expectedto reach operational service by 2018. To someextent, this aircraft is a next-generation versionof the existing B-2A stealth bomber, drawing onadvances made during the development ofunmanned aircraft such as the X-47B Pegasus.It is expected to receive the designation B-3.Northrop Grumman/Bill Rose Collection

An early Lockheed Martin proposal for the USAF'sNext Generation Bomber. like the NorthropGrumman design, this also makes extensive use ofnew materials and advances in stealth technologymade during the development of unmannedmilitary aircraft. Northrop Grumman/Bill Rose Collection

The experimental Northrop Grumman X-47BPegasus Unmanned Combat Aircraft (UCAV) whichhas been used to develop new technologies thatwill be employed in the crewed Next GenerationBomber. Northrop Grumman

120 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (J980-2030) 121

concept that may simply be too expensive todevelop as a parallel programme to the NGBwith recent estimates for the FB-22 programme varying from $7-10 billion.

Many aviation observers have suggested thatthe F-35 Lightning 11 will be the last mannedfighter aircraft of any significance, but artwork released in July 2009 by Boeing's Phantom Works shows a manned 'sixthgeneration' combat aircraft intended toreplace the current F/A-18f/F Super Hornetafter 2025. This tailless design has been proposed to meet the US Navy's future F/A-XXrequirements and it will have been conceivedfrom the outset to be as stealthy as possible.That said, it goes without saying that currentillustrations do not reveal any important orinnovative design features.

The exact definition of 'sixth generation'remains unclear, although we should expectan aircraft with supercruise, increased range,thrust vectoring, internal weapons carriage,advanced sensors, lower maintenancerequirements and improved stealth. Primarilyintended for carrier-based operations, the air-

Boeing's Phantom Works has revealed a newconcept for a US Navy F/A-XX fighter to replace theF/A-18E!F Super Hornet in the mid-2020s. The twoseat, blended-wing, twin-engine, tailless designis dubbed a 'sixth-generation fighter' and willembrace technologies such as visual stealth,advanced electronic attack capabilities and optionalmanning. Although not yet a formal requirement,the Navy is thought to be considering both mannedand unmanned options for F/A-XX. Boeing

fore a considerable reduction in operatingcosts. Comparisons with similarly specifiedconventional jet airliners suggested a 20-25per cent improvement in fuel efficiency.

NASA has supported the BWB design fromthe outset. It determined that this type of aircraft showed great potential as a large capacity subsonic airliner. This led to BWB modelsbeing wind tunnel tested at NASA Langleyand the commission of a scale-size remotecontrol prototype that was built at StanfordUniversity by a team directed by Dr BenTigner and Associate Professor Han Kroo. Thissmall aircraft was designated BWB-17(because of the 17ft (5.18m) wingspan) and itflew for the first time on 29 July 1997 at EIMirage Dry Lake, California.

It seemed that there were relatively fewnegative features to the BWB design. Longitudinal stability, which is often a major problem with tailless designs, could bemaintained by the latest active flight management systems, although there were concernsabout the suitability of BWB aircraft for manyexisting airports and the fact that there wouldbe few, if any windows available for passengers. Early proposals for a 368-passengerBWB airliner were based on a proposedrange of 9,500 miles (I5,000km) and Mach0.85 cruise. By 1994, NASA was suggestingthat the McDonnell Douglas engineers shouldconsider a much larger aircraft capable ofcarrying 800 passengers for 8,000 miles

craft would be designed for compact storage.Flown by a crew of two, the aircraft may beconfigurable for unmanned operations orbuilt as a UCAV version.

Whether or not such an aircraft willbecome a reality when faced with the nextgeneration of completely unmanned designsis hard to determine at present. But it is possible to say with some degree of certainty thata manned F/A-18E/F replacement will becostly to develop, especially if undertakenseparately from any future manned multi-rolecombat aircraft requested by the USAF.

Blended Wing Body Designs

The Blended Wing Body (BWB) aircraft can betraced back to Junkers and Burnelli, althoughthe modern BWB design is generally attributedto a research programme initiated by McDonnell Douglas at Long Beach, California.

Work on this project began in late 1988with the aim of developing a more efficienttransport aircraft. The McDonnell Douglasteam, which included Bob Liebeck, Mark A.Page and Blaine K. Rawdon, steadily refinedthe concept into a proposal resembling ahybrid-flying wing. The aim was to utilise aneffective aerofoil-shaped body fitted withhigh-lift wings, but it was also important toallow the internal installation of easily fabricated pressurised tubular compartments. Asthe project evolved, it became increasinglyclear that the BWB design would offer significantly improved aerodynamic efficiencyover existing aircraft designed for the samepurpose. A 10-15 per cent reduction in weightwould also be possible if composite materialswere used extensively in the aircraft's construction. These factors would mean lowerengine thrust for the same payload and there-

2UnknownUnknown72ft (22m) approxUnknown84,000-1 00,000 Ib(38, I00·45,000kg)2x Pratt &Whitney F135afterbuming turbofan engines,based on the F119 developed forthe F·22. The FI35 engine canproduce 34,0001b (I5IkN) drythrust and 50,000 Ib (222kN)afterburning thrust. The GeneralElectric/Rolls-Royce F136afterburning turbofan, which wasproposed at one stage, would offersimilar performanceMach 1.865,000ft (I9,812m)1,600 miles (2,575km) un-refuelled30 x 250 Ib (I 13kg) Small DiameterBombs (SOB). Larger conventionaI or nuclear bombs, guidedweapons. Anti-radiation missilesand 2-4 AMRAAM air-to-air missilesfor self-defence. Perhaps later,stealthy underwing pods carryingordnance, fuel or EW equipment

FB-22

Propulsion

CrewWingspanWing areaLengthHeightGross weight

Maximum speedCeilingCombat rangeArmament

Boeing F/A-XX

Although described as an F-22 modified tobecome a stealthy light bomber, the FB-22would effectively be a brand-new aircraftwith a completely new wing and probably notail or vertical stabilisers. This cleaner designwould improve the aircraft's stealthiness,aerodynamic properties and help to reducemanufacturing costs. The fuselage would bestretched by about lOft (3m) and approximately 80 per cent more fuel would be carried. There would be enough internal storagefor up to 30 small diameter 250lb (I 13kg)bombs utilising GPS for precise targeting. TheFB-22 would also be capable of deliveringanti-radiation missiles and nuclear weapons.

For self-defence, the FB-22 would carry atleast two and perhaps four AMRAAMs internally or possibly a laser weapon, but this is notan aircraft that is intended for use as a fighter.Engines would be upgraded to two powerfulPratt & Whitney FI35s developed from theafterburning turbofans used for the F-22. Airfor the engines would be drawn through tworeconfigured stealthy intakes and the abilityto cruise at supersonic speed has been suggested but this remains unclear. However,the FB-22 would be the fastest bomber inUSAF service. Possessing a maximum speedof Mach 1.8, the two-man FB-22 would havean unrefuelled range of 1,600 miles(2,575km) and deliver its bomb load from analtitude of 60,000ft (I8,288m). The FB-22would be equipped with sophisticated threatdetermination systems and have the ability tocapture high quality radar images of groundtargets which could be relayed to a commandcentre in real time.

A completely tailless technology demonstrator based on an F-22A airframe was proposed and it received the designation X-44A.This experimental aircraft was intended to usethrust vectoring for all flight control functionsand the project would have provided usefulresearch data for the FB-22, but at the time ofwriting the X-44 remains officially unbuilt. TheFB-22 would fill the place once occupied bythe variable-geometry F-II\. It would effectively replace the F-15E, taking over some missions currently better suited to the B-1 BandB-2A. It is probable that various FB-22 modelshave undergone wind tunnel and radar tests.This aircraft remains an interesting and viable

This artwork shows the possible appearance of astrike aircraft based on the F-22A Raptor stealthfighter which would receive the designation FB-22.This would be almost an entirely new aircraft witha stretched fuselage, new wing and more advancedengines. Although this proposal has much in itsfavour, the cost of development is likely to remainprohibitive and there are no plans at present toinitiate such a programme. Bill Rose Collection

Lockheed-Martin FB-22

When it became clear that the USAF wouldneed to supplement or start to replace itsexisting bomber fleet by 2018, several designswere proposed that built on existing technology and could be delivered within an acceptable timeframe. One suggestion was toreplace the existing B-1 B Lancer with a newversion of the aircraft called the B-1 R(Regional). Re-engined with new avionics, anew radar system, external hardpoints andair-to-air missiles, the B-1 R would regain theB-IA's Mach 2+ performance. It is also possible that the B-1 R might be configured tolaunch cruise missiles, although this capability is currently restricted by the Strategic ArmsLimitation Treaty I (SALT I). While this proposal has obvious merits, the existing B-IBhas a reputation for being unreliable, it isdemanding to maintain and the B-1 R will notbe any stealthier than the current aircraft.These observations may help to explain whythe B-1 R was rejected as an interim solutionto USAF requirements.

Another possibility that is rumoured to havereceived serious consideration was a stealthystrike aircraft based on the unsuccessfulNorthrop YF-23 fighter. This does not appearto have been regarded as a realistic option,either for technical reasons or on the groundsof cost. But a third idea that generated considerable interest was a strike aircraft basedon the advanced, stealthy Lockheed-MartinF-22 Raptor fighter. This suggestion originatedwithin the Skunk Works during 2002 and adetailed study was funded by the company.The design may have been linked to a proposed experimental tailless version of theF-22 called the X-44A.

Powerplant Readily available turbofan enginesMaximum speed SubsonicCombat radius +2,000 miles (t3,200km)Ability to carry nuclear weaponsWeapons load 14,000-28,000Ib (6,350-12,700kg)First flight By 2018

which is now part of the US Navy's UCAS-Dcarrier-based aircraft project. Boeing produced the X-45 series of unmanned demonstrators leading to the advanced PhantomRay which is due to fly in 20 I O. In the case ofLockheed's Skunk Works, it already had considerable expertise with low-observabletechnology and recently flew the P-175 Polecat unmanned stealth aircraft as a companyfunded technology development venture.

Preliminary artwork for the NGB shows thatthe principle designs hold no big surpriseswith concepts from both groups resembling across between the B-2A and a scaled up hightech UCAV. It is interesting to note thatNorthrop-Grumman has already proposed anunmanned X-47C with a 172ft (52,4m)wingspan and a 1O,0001b (4,536kg) payloadcapability.

A straightforward approach to development of the NGB is favoured by the US AirForce which requires an aircraft with arealistic delivery date. Noticeable improvements will be in low-observable, avionics,fuel efficiency and maintenance requirements. It is anticipated that the 2018 NGB willreceive the designation B-3, although thisnew bomber is seen as something of a stopgap until a more advanced stealthy longrange supersonic aircraft becomes availablein 2037.

NGB Specifications

122 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (I980-2030) 123

BWB-450. These designs had wingspans from199ft (60m) to 222ft (67.6m), although a verylarge version known as the BWB-IOOO wasstudied. This would have a wingspan of 262ft6in (80m), a length of 193ft I Din (59m) and agross weight of 650 tons (589 metric tons).While a fuel-efficient airliner was the originalaim of this long-term programme, it nowseems likely that BWB technology will beapplied to military designs first. Boeing isknown to have conducted extensive studiesinto military adaptations of the BWB designwith proposals for a BWB tanker to meet futureUSAF requirements. The BWB tanker would beequipped with two hose/drogue refuelling stations and up to three smart booms capable offully automated refuelling of multiple numbersof piloted or unmanned aircraft.

An obvious military application for the largerBWB aircraft would be a transporter, while along range and the ability to loiter for lengthyperiods would make this aircraft suitable forcommand control, surveillance, reconnaissance or maritime operations. It is also likelythat a BWB aircraft would make a suitableplatform for one or more laser weapons, eitherto intercept ballistic missiles during their boost

Above right: The general layout for a three-engine,intercontinental 529-seat airliner. One factor oftendiscussed with this design would be the lack ofwindows, although video displays would provideexternal views for passengers. NASA

Top right: Tail view of the unmanned X-48B BWBdemonstrator during its first test flight at EdwardsAFB. NASA

Top left: The Blended Wing Body X-48Bdemonstrator undertakes its first test flight atEdwards AFB on 20 July 2007. NASA

Right: One of several Boeing proposals for a BWBtanker aircraft. This would be capable of fullyautomated refuelling operations involving mannedand unmanned aircraft. Bill Rose Collection

nations X-48B being assigned to both modelsin June 2005. The first X-48B was wind tunneltested by NASA in May 2006 and then shippedto Dryden Flight Research Center at EdwardsAFB where it would act as a backup for thesecond aircraft that was scheduled to beginflight-testing.

Powered by three small jet engines, eachrated at 50 Ib (.22kN) thrust and having a takeoff weight of 520lb (235kg), the X-48B wasstill expected to attain a maximum speed of138mph (222kph) and achieve an altitude of10,000ft (3,048m). Ground testing began inlate 2006 with the first flight taking place on 20July 2007. This lasted for 31min and the aircraft climbed to an altitude of 7,500ft(2,286m). Trials have continued withincreased participation from the Air ForceResearch Laboratory (AFRL) which recognised the military potential of the BWB designsome time ago.

Boeing has developed a series of commercial configurations for the BWB configurationknown as the BWB-250, BWB-350 and

have a wingspan of 249ft (75.8m) and usethree large turbofans for propulsion.

The outcome to this change in direction wasthe construction of several wind tunnel models that were tested at NASA Langley and asmall-scale unmanned proof-of-conceptdemonstrator that was initially designated asthe BWB-LSV (Low Speed Vehicle). Workbegan on the 35ft (I 0.6m) wingspan BWB-LSVat Langley in 2000 with the name changed toX-48A in 2001 to reflect its experimentalnature. The X-48A was essentially a 14 per centscale sized version of the BWB-450, makingextensive use of composites in its construction. Unfortunately, unforeseen problems withthe flight control system and budgetaryrestraints brought the project to a halt in 2002.

Soon after this, the X-48A was scrapped.Small wind tunnel models replaced thedemonstrator and it was planned to build twocompact unmanned prototypes with 21ft(6.4m) wingspans. Development and construction of these aircraft was undertaken byCranfield University in Britain with the desig-

Above right: Rear view of a Boeing Blended WingBody (BWB) 450-passenger subsonic transport testmodel in the wind tunnel at the NASA LangleyResearch Center during 2000. NASA

Right: The sleek looking sub-scale X-48B BWBprototype is prepared for testing in the full-scalewind tunnel at NASA Langley in May 2006. Boeing

Above: A three-engine blended wing body testmodel undergoing antenna pattern measurementsduring 1998. NASA

(l2,800km). This scaled-up design wouldrequire two layers of cylindrical pressurisedcompartments, at least four engines, anincreased wingspan approaching 350ft(106m) and an empty weight of approximately 200 tons (180 metric tons).

In 1997, McDonnell Douglas became part ofthe restructured Boeing Company and it wasdecided to continue with the promising BWBprogramme. But there were concerns thatthe project was distancing itself from anynear-term commercial applications. TheEuropean Airbus Corporation was pushingahead with development ofa super Jumbo jetand as a consequence Boeing decided thatthere was no immediate room in the marketfor another aircraft in this class. It meant thatfurther development of an 800-seat passenger BWB airliner was suspended with a 450seat aircraft using unconventional aerofoilsbecoming the new primary objective. A seriesof in-house classifications were introducedfor the BWB designs with the 450-seat aircraftbecoming the BWB-450. This model would


Artwork depicting a twin-engine Boeing BWBtanker design. Boeing

A twin-engine Boeing BWB proposal, suitable foruse as a military transport aircraft. Boeing

A BWB design produced in 2005 by the BoeingPhantom Works for a CESTOL (Cruise EfficientShort Take-off & Landing) aircraft. This designwith the reference AB32 would use 12 embeddedATSE (Advanced Technology Short Engines),each providing 5,000 Ib (22.2kN) thrust. An initialapplication could be a military transport aircraft.Boeing Phantom Works

phase or for use against ground targets. Otherpossibilities are a launch platform for the nextgeneration of high-performance cruise missiles or the delivery of free fall bombs orJDAMS. In this respect, such an aircraft couldeventually replace the B-52 bomber, perhapsas the B-4. Sufficient clearance beneath theaircraft might also permit the carriage of asmall orbital manned or unmanned spacecraftfor release at altitude.

The stealthiness of a BWB design remainslargely unknown or classified and while technical opinion appears divided on this issue, it hasbeen suggested that engines and their locationsmay present problems. The BWB design hasbeen the subject of a long-term study at Lockheed-Martin, while Aerospatiale consideredthe BWB for the Very Efficient Large Aircraft(VELA) programme. In Russia, there has been anumber of state-sponsored research programmes producing concepts broadly similarto those created in the West. It is impossible toaccurately predict the state of aviation by themiddle of this century, but it seems highly probable that by then, the BWB design will havebecome a familiar sight in our skies.

Oblique Flying Wings

A flying wing aircraft that could swivel aboutits vertical axis during flight would theoretically provide good performance at lowspeeds while also allowing high-speed orsupersonic flight when moved to an obliqueangle. Unfortunately, the engineering complexity of such a design remains considerable, and to date there have been no practicalapplications of this idea.

It's probable that Dr Richard Vogt of Blohm &Voss made the earliest serious proposal for utilisation of an oblique wing during World War 2.He conceived a variable-geometry jet fighterknown as the P.202 with a wing that swivelledaround a central pivot to provide variablesweep. Models are believed to have been windtunnel tested, but the concept progressed nofurther. The oblique wing was also studied by

Messerschmitt at Oberammergau as part of theP.llOl experimental fighter project, but it wasconsidered too radical for further development. In the post-war years, the idea was studied over a lengthy period by the AmericanNACNNASA aerodynamicist Dr RobertThomas Jones (1910-1999) who recognisedthe advantages of an oblique (or asymmetrically-swept) wing aircraft. He also realisedfrom the outset that major design challengesexisted which might take years to resolve.

In 1958, Jones outlined his ideas for anoblique flying wing (OFW) concept at the firstInternational Congress of the Aeronautical Sciences held in Madrid. Attending the conference were Handley Page aerodynamicistsLachmann and Lee who took serious notice ofJones' ideas. As a consequence, Godfrey Leebegan work on his own OFW design study fora 150-seat, Mach 2 airliner that he completedin early 1961 calling it Sycamore. The aircraftwas very unusual in appearance, taking theform of large semi-elliptical wing with an overall length of about 300ft (91 m). This was fittedwith a swivelling crew nacelle at the starboardwingtip and a stabilising fin at the other.Beneath the centre of the wing were four swivelling jet engines in pods that controlled theyaw angle from 25° at low speeds to 72° duringsupersonic flight. The RAE undertook windtunnel tests, but Lee's Sycamore airliner wasgenerally considered too far ahead of its timeto be a practical proposition.

Interest in oblique wings faded until theearly 1970s, when RT. Jones re-generatedawareness with a number of supersonictransport aircraft proposals, including a veryunusual twin fuselage concept. This led toseveral short-term studies undertaken by Boeing, General Dynamics and Lockheed whichtried to determine civil applications for theOFW. At the same time NASA Ames undertook studies into military applications of theOFW, initially producing designs for a landbased anti-submarine warfare (ASW) aircraft

Similar in many ways to the earlier British Sycamoreconcept, this long-range supersonic oblique wingairliner was one of several concepts to be producedby NASA during the early 1990s. NASA

This multiple exposure photograph of NASA'sOblique Wing Research Aircraft made in 1976shows the wing rotation limits to 45 degrees.This small, unmanned research vehicle providedinvaluable data, which allowed construction of amuch larger experimental manned aircraft. NASA

NASA's Oblique AD-I (Ames-Dryden-l) researchaircraft in flight. This small single-seat jet-poweredresearch vehicle was built after extensive testing ofwind tunnel models and first flew on 21 December1979 at Edwards AFB. Avery successful series oftrials followed, lasting until autumn 1982. NASA

126 Secret Projects: Flying Wings and Tailless Aircraft US Manned Tailless Aircraft (J980-2030j 127

Northrop Switchblade: Production Version

Right: This illustration shows a proposed NorthropGrumman oblique flying wing aircraft with the wingswept for supersonic speed. Northrop Grumman

Unmanned200ft (6Im)O't060'2xunspecified afterbumingturbofan enginesMach 1.8 -260,000ft (I8,288m)5,600 miles (9,000km)

Middle: Equipped with swivelling engine pods,this Northrop Grumman proposal for a supersonicoblique wing demonstrator shows the wingconfigured for a speed of Mach 0.73 (upperillustration) and fully swept (below) at Mach 1.2.The design was part of a multi-million dollar studyfunded by DARPA leading to the constructionof an unmanned flying prototype. However, theprogramme came to an end in 2008 and at thepresent time, there seems little likelihood offurther development. DARPA

Bottom: An advanced Northrop concept for anunmanned oblique flying wing releasing a JDAM.Details of the integral engine system have beenintentionally left unclear, but it seems likely thatthe central section of the wing containing thepropulsion system would rotate within the wing.Northrop Grumman

Calspan, Buffalo, New York. As the project progressed, the name Switchblade was beingloosely used for the proposed Mach 1.2demonstrator. The wing would have a span of56ft (17m) and the oblique sweep could bevaried from 0° to 65°. Two General Electric J8521 afterburning turbojets would be housed ina centrally-positioned swivelling unit, but testsindicated that individual pods were more satisfactory and the design was modified.

The undercarriage is understood to haverepresented something of an engineeringchallenge and finally consisted of fullyretractable main gear located between theengines with a castoring tailwheel. A furtherdesign for a proposed production aircraft carried the engines in a central swivelling section that was integral with the wing, but nodetails of this have been released.

Areview of the OFW project was scheduledfor March 2008 and Northrop-Grumman hopedit would lead to the construction of a demonstrator, but within a matter of months, DARPAhad decided to conclude the programme. Theexact reasons are unclear, but it is believedthat financial restraints were responsible.

At the present time, it is hard to say if thereis a future for the manned or unmannedoblique flying wing, but it seems probablethat the concept will reappear at some point.

Maximum speedCeilingRange (approximately)

CrewWingspanSweepPowerplant

were not totally dissimilar to Lee's Sycamorewere completed. The aim was to produce a480-seat supersonic airliner with a range of6,329 miles (lO,OOOkm) for possible introduction by 2020. The estimated maximum speedwas about Mach 1.8 and the wing would havean oblique sweep of 37.so during take-off andlanding, moving to 68° during supersoniccruise. One of the biggest problems to emergeduring this study was undercarriage designand airport handling, although it now seemedthat the oblique wing would be capable ofproviding supersonic performance for aboutthe same operating costs as a conventionallong-range jet airliner.

In August 1992, the study was expanded toinclude engineers from Boeing and McDonnell Douglas, plus a small research groupfrom Stanford University. This led to manydesign refinements and two definitive proposals known as OAW-I and DAC-1. Windtunnel models were tested and NASA Amesfunded the construction of two small remotecontrol OFW aircraft at Stanford University.These were built by Steve Morris and flown in1993 and 1994. However, at the end of thisprogramme, the representatives of Boeingand McDonnell Douglas were both in agreement that the design had no near-term commercial potential and their involvement withOFW development came to an end.

DARPA was the next US Governmentagency to take an interest in the OFW and itenvisaged an unmanned vehicle, configuredfor specialised reconnaissance or strike missions. Its initial specification was for a reconnaissance aircraft with an operational radiusof 2,858 miles (4,600km) and the ability to loiter for IS hours at 60,000ft (l8,288m) whilecarrying a 4,0001b (I,800kg) payload. Thestrike aircraft would have the same operational radius with a larger 15,000 Ib (6,800kg)payload, a cruise speed of Mach 1.6, subsonicloiter and a maximum speed of Mach 2.0. Itwas hoped that one design could be adaptedfor either role with the provisional serviceentry date set at 2020.

In March 2006, DARPA awarded NorthropGrumman a $10.3 million contract for a twoyear design and development programme thatwould result in proposals for an experimentalOFW demonstrator. DARPA hoped that thisproject would lead to the construction of asupersonic test vehicle within five years. Byautumn 2007, Northrop-Grumman had startedsupersonic wind-tunnel trials of models at

A Northrop Grumman concept for an unmannedoblique flying wing aircraft. This artwork showsthe wing configured for low subsonic speeds.The propulsion system is contained in a single podbelow the wing. Northrop Grumman

tests with scale-sized models, and then AmesIndustrial (no connection to NASA) was contracted to build a single prototype. The oneman AD-I made its first flight on 21 December1979 at Edwards AFB, piloted by Thomas C.McMurtry. In total, the AD-I undertook 79flights and the last of these took place on7 August 1982 with McMurtry at the controls.During testing, the wing was swept to a maximum of 60° with several landings made withthe wing positioned at 45°. The AD-I is nowon display at the Hiller Aviation Museum inSan Carlos, California.

There were plans to follow the AD-I with asupersonic Oblique Wing Research Aircraftbased on NASA's Digital Fly-By-Wire (DFBW)Vought F-8 demonstrator. But it became clearthat problems would arise using the F-8because the undercarriage would have prevented landings at high angles of attack. Furthermore, flight simulations indicatedunacceptable issues would arise with lateralacceleration during pitch manoeuvres thatneeded to be addressed, so it was decided notto proceed with the construction of this aircraft which would have been partly funded bythe US Navy. Rockwell also studied a carrierbased fighter equipped with an oblique wingduring the 1980s. A fighter with the ability toloiter for long periods and then interceptenemy aircraft at supersonic speed would bean attractive proposition and as a bonus, theoblique wing would allow very efficient storage onboard a carrier. But the US Navy wasunwilling to divert substantial funding from itscostly A-12A programme and the project wasabandoned. Jones officially retired from NASAin 1981 and accepted a senior position at Stanford University, although he continued to actas a consultant for NASA Ames until 1997.

Despite cancellation of the oblique wingF-8, NASA Ames continued to work on obliqueall-wing designs. In 1991, several designs that

with modest supersonic performance andgood endurance. Another proposal was anunmanned air-combat aircraft which lookedrather like a large surfboard with a swivellingfuselage section below the wing that carriedtwo external missiles. Air launched and powered by two afterburning turbojets, this UCAVwould have a maximum speed of Mach 1.6and high manoeuvrability with an II G limit.The folded length was about 35ft (l0.6m), soit is conceivable that a couple of these aircraftmight have been carried beneath a B-52bomber for defensive purposes. After firing itsmissiles, the UCAV could have been flowninto the path of an enemy aircraft as the UCAVwas considered expendable once launched.However, making such an advanced systemwork with 1970s technology might haveproved rather demanding.

Further applications of the oblique wingwere an advanced tactical fighter with a fairlyconventional fuselage, an unusual strategicmissile launch aircraft and several missiledesigns. Although these studies were undertaken just to establish the limits ofwhat mightbe possible with the oblique wing, R.T. Joneswas already involved with the building andsuccessful testing of small radio-controlledOFW models. It is also worth mentioning thatTeledyne-Ryan was asked to investigate thepossibility of adapting a supersonic BQM-34FFirebee II remotely-piloted research vehicleas an oblique wing test-bed and a model waswind tunnel tested during the early 1970s.That seems to have been the full extent of thisproject which ended in the mid-1970s.

NASA Ames Research Center and NASADryden Flight Research Center were now collaborating on plans for a manned aircraft anda decision was made to proceed with a small,low-speed jet powered prototype called theAD-I (Ames-Dryden-!). Initially, NASA Amesand NASA Langley conducted wind tunnel


Chapter Six

Soviet Tailless Designs

BICh-14 was produced at the MenzhinskyFactory. Most of the airframe was built fromwood or aluminium alloy and the aircraft wascovered with fabric. Powered by two M-I I100hp (74.5kW) piston engines, the BICh-14had a wingspan of 53ft 2in (16.2m), a wingarea of 646ft' (60m') and an overall length of19ft 8in (6m). With the provision for five seats,BICh-14 had a maximum take-off weight of4,1881b (1 ,900kg), allowing a maximumspeed of 136mph (220kph) and a useful landing speed of 43mph (70kph). BICh-14 new forthe first time in 1934, but it was not a successand like the earlier Cheranovsky aircraft, itlacked stability and suffered with variousaerodynamic shortcomings. BICh-14 continued to ny until 1937 when it was finallyscrapped.

In early 1935, Cheranovsky was sent towork for Leonid. V. Kurchevsky who ran theSpecial Tasks Collective. Kurchevsky haddesigned a series of recoilless guns and it wasnow planned to build a new fighter aircraftthat could carry two specially designed largecalibre APK cannons. Cheranovsky proposedan improved version of the BICh-7A with thecannons mounted in the wings. There issome confusion about these cannons whichare usually described as being of a recoillessdesign with an 80mm calibre. Research suggests this weapon may have been a modifiedversion of the APK 76.2mm recoilless cannonusing a reloading system operated by compressed air and fed from a magazine canying5 or 6 rounds. Whatever the exact specification, it seems this weapon was not a great

Various problems with the BlCh-7 led Cheranovskyto extensively modify the design leading to a redesignation of this aircraft as the BICh-7A.Bill Rose Collection

It appears these experiments were cancelledon the grounds of safety and BICh-11 mayhave nown with a small piston engine drivinga rear mounted pusher propeller.

Work on BICh-7A was finally completed inearly 1932 and the reconfigured aircraft madeits first night soon afterwards with N.A. Blaginundertaking all the initial tests. Despite someproblems with engine vibration, the BICh-7Awas a considerable improvement over its predecessor, but the aircraft remained something of an experimental curiosity andCheranovsky returned to the drawing board tocontinue with development of his parabolicdesigns. This led to the twin engine BICh-14which was designed as a light utility aircraft.

As another State-sponsored project, the

A scaled-up version of the B1Ch-3, the two-manBICh-7 powered by a IOOhp (74.5kW) BristolLucifer radial engine, undertook its first flight in1929. Bill Rose Collection

wingspan of 31ft 2in (9.5m), a wing area of215ft' (20m'), an overall length of 11ft 6in(3.5m) and a gross weight of approximately5071b (230kg).

BICh-3 was mainly constructed from woodand covered in fabric. The pilot sat in a centrally-located cockpit which was faired intothe tailfin. A fixed undercarriage was used,comprising of two forward wheels with fairings and a simple tailskid. The aircraft madeits first night in February 1926, piloted by B.N.Kudrin and there are mixed reports aboutBICh-3's capabilities. BICh-3 could reach amaximum speed of about 85mph (I36kph)and the landing speed was an impressive24mph (40kph), allowing touchdowns in aremarkably short distance. It is also said thatthe aircraft handled quite well, but still exhibited stability problems. During the remainderof the 1920s, Cheranovsky continued todesign unusual parabolic-shaped tailless aircraft, including the BICh-5 twin-enginebomber, but none progressed beyond plansor small models.

His next full-sized experimental design toreach construction and testing was the moresubstantial two-man BICh-7 which undertookits first night in 1929. BICh-7 had a wingspanof 40ft (12.2m), a length of 15ft 5in (4.74m)and a wing area of 323ft' (30m'). Power wasprovided by a 100hp (74.5kW) Bristol Luciferthree-cylinder air-cooled radial engine driving a forward mounted two-blade propeller.BICh-7 was fitted with two tandem opencockpits and a rather unsatisfactory undercarriage that consisted of a central wheel andwingtip skids. With a gross weight of about1,9071b (865kg), this allowed a maximumspeed in the region of 100mph (160kph) anda landing speed of43mph (70kph). There wasno tailfin, but rudders were fitted to thewingtips. Exactly how many test nights wereundertaken is uncertain, but it quicklybecame apparent that BICh-7 was velY difficult to ny and dangerous to land, leadingCheranovsky to extensively modify thedesign.

This resulted in the BICh-7A being fittedwith a conventional fixed-position undercarriage and a re-designed fully-enclosed cockpit that trailed into the tailfin. Cheranovskywas now heavily involved with other projects,so the work progressed slowly. These otherprojects included two small gliders (BICh-8and BICh-I1) with the BICh-11 beingintend d for trials with a small rocket engine.

combat jets, these aircraft were relativelyconventional, with tailless designs progressing little further than the prototype stage. During the decades that followed, Sovietdesigners would occasionally propose tailless configurations, but nothing significantwas produced.

However, the Americans were makingrapid advances in stealth technology and thisencouraged the Soviets to consider new longrange manned and unmanned high-altitudespyplanes and bombers, often utilising nyingwing layouts. Most details of this work remainclassified, but the main programme appearsto have been abandoned when the Sovieteconomy collapsed in the early 1990s. Nevertheless, it is possible that this researchresumed, perhaps being utilised for anunmanned high-altitude spyplane.

The first .notable tailless Russian aircraft wasdesigned by Boris Ivanovich Cheranovsky(I 896-1960). He had grown up with a fascination for manned night and joined theZhukovsky Academy in 1922, making initialproposals for a nying wing aircraft during thesame year.

In 1924, he completed work on two smallSingle-seat parabolic-shaped gliders whichreceived the names BICh-1 and BICh-2.These experimental aircraft were consideredquite avant-garde for their time, especially asthe entire trailing edge was taken up withcontrol surfaces. It appears that there werehandling problems with BICh-l, but BICh-2 issaid to have performed somewhat better innight showing improved stability. The nextdesign, BICh-3, was based on BICh-2. Themain difference was a small 18hp (13.4kW)Blackburn-Tomtit 698cc inverted V-twinengine, driving a 4ft 7in (I40cm) propeller atthe front of the aircraft. Completed by Cheranovsky by the end of 1925, BICh-3 had a

Cheranovsky's Tailless Designs

A demonstration flight of Boris Cheranovsky'ssmall one-man parabola-shaped BICh-Z glider,probably during the 1924 glider contest.Bill Rose Collection

being develop d which had the ability toreach North America.

During the immediate post-war period,information gathered by Western intelligenceagencies on military developments within theSoviet Union was extremely limited and unreliable. So when the CIA circulated the ideathat Russia was building a massive neet of1,800 nying wing bombers based on Hortendesigns, it was taken very seriously.

One declassified US Intelligence documentfrom 1949 (USAF Directorate of Intelligence100-203-79 CY) had the following to say: 'It isbelieved that Dr Boch has made available allGerman plans for nying wing type aircraft tothe Soviets.' The document goes on to say:'Among the designs considered by the Germans and possibly exploited by the USSR, arejet-propelled, nying wing type aircraft whoseconfiguration would be similar to descriptions of certain objects reported nying overthe US. The estimated speeds of such aircraftare within range of the lower limits of speedattributed to nying objects over the US. It is notimpossible that emphasis on surpassing foreign developments has led to unusualprogress in fuels and propulsion by the USSR.'

These concerns were totally groundlessand while wartime German know-how wasfully utilised for the first generation of Soviet

Many innovative and advanced aircraft weredesigned and built within the Soviet Union.Engineers were encouraged to experimentwith unorthodox concepts and the history ofRussian tailless aircraft design and construction stretches back to the pre-war years. During this time, designers such as Cheranovsky,Kalinin and Belyaev all saw their tailless concepts progress from the drawing board tofunctional hardware, although none of theseaircraft reached production.

At the end of World War 2, vast amounts ofadvanced German military technology werecaptured by the Russians and shipped east forevaluation and exploitation. This equipmentwas accompanied by thousands of Germanengineers and scientists who were internedby the Russians and one of these prisonerswas Professor Gunter Boch (1898-1970) whoheaded Germany's wartime nying wing projects. As the war progressed Germany hadgiven increasing priority to the developmentof tailless combat aircraft, seeing variousaerodynamic and production advantagesover more conventional designs. Subs quently, the Russians decided to study andcapitalise on this approach, keeping Bochand his associates in custody for many years.Aware of this situation, the Pentagon believedthat advanced nying wing jet bombers were

130 Secret Projects: Flying Wings and Tailless Aircraft Soviet Tailless Designs 131

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tailfin with a rudder. A tricycle undercarriagewould support the BICh-26 on the ground.The forward pressurised cockpit was nankedby contoured engine intakes which suppliedair to the single Mikulin AM-5 turbojet rated at4,4091b (44kN) static thrust. It was claimedthat this aircraft could attain a maximumspeed of Mach 1.7 at 23,000ft (7,000m) andreach an altitude of 72,000ft (21 ,945m). Thisappears to be rather wishful thinking! Nodetails of armaments are quoted, but cannons located towards the nose of the aircraftwould seem probable.

BlCh-26 was never built and it is believed tobe Cheranovsky's last major design. He isunderstood to have retired soon after completing work on this proposal, suffering withpoor health. Cheranovsky died in Moscowduring 1960.

Che-24. Looking rather like the Douglas F-4DSkyray, this design was expected to appear inpublic during 1949.

An image showing a wind tunnel modeldoes not reveal the position of air intakes fora jet engine. Conceivably, a prototype wasbuilt, but there is no documentation to support this. The BICh-25 (Che-25) is understoodto have been a variable-geometry conceptand Cheranovsky followed this with a supersonic fighter design in 1948, bearing the reference BICh-26 (Che-26) and clearly adevelopment of the BICh-24. The airframeand skin would be built almost entirely fromlightweight alloy and steel with a wingspan of23ft (7m), a wing area of 291 ft' (27m') and alength of 29ft 7in (9m). The gross weight wasset at 9,9211b (4,500kg) with control surfaceson the trailing edge of the wing and a swept

A small wind tunnel model of the B1Ch-24 jetfighter. Looking rather like the Douglas F-4DSkyray, it remains uncertain if this designprogressed to the hardware stage, although theaircraft was expected to appear in public during1949. Bill Rose Collection

The advanced BICh-26 (Che-26) jet fighter appearsto have been based on the BICh-24 and wasexpected to have a supersonic and high altitudecapability, which appears rather optimistic bearingin mind the engine technology of that era.Bill Rose Collection

success and there were serious problemswith the reliability of the loading system.However, the Cheranovsky fighter wasapproved for construction by mid-1935 andassigned the reference BICh-17. The new aircraft had a wingspan of 40ft (12.2m) and alength of 16ft 5in (5m). Power was providedby an M-22 engine rated at 480hp (358kW).The airframe was mainly constructed fromwood and fitted with a fully-retractableundercarriage. By February 1936, about 60per cent of the BICH-l 7 had been completedwhen Kurchevsky's operation was disbandedon the direct orders of Stalin and the fighterproject was scrapped.

Boris Cheranovsky continued to designunconventional aircraft, leading to the BICh-21.This was an advanced, very sleek taillessdesign that was built by 1940 and new for thefirst time in June 1941. It was planned to enterBiCH-21 for the AJI-Union Air Race scheduledfor August 1941, but the event was cancelleddue to the war. Little is known of Cheranovsky's wartime activities, although a remarkable design was unearthed by Yefim Gordonand Bill Gunston while researching the book

Soviet X-Planes (Midland Counties, 2005).The reference for this design is unknown,

but it dates from 1944 and shows a surprisingly futuristic jet fighter, looking rather likethe cancelled A-12 Avenger II stealth attackaircraft which was developed during the late1980s. Cheranovsky's small, one-man fighterwas to be powered by two turbojets buried inthe wings with leading edge air intakes. It hasbeen suggested that the intended jet enginemay have been the Lyul'ka VRD-2 designwhich was under development at the time.Almost triangular with no upright stabiliser,the jet fighter used two large elevons for nightcontrol and was equipped with a tricycleundercarriage. Two cannons were positioned on each side of the cockpit with thebarrels protruding beyond the leading edge.No specifications for this little-known designare thought to exist.

After World War 2 ended, Cheranovskycontinued to work on proposals for jet fighters with the BICh-24, also referred to as the

40ft (12.2m)Unknown16ft 5in (5m)

I x M·22 480hp (357kW)pi ton engine2xAPK recoilless cannons(probably 762mm)

I23ft (7m)291 ft' (27m')29ft 7in (9m)

9,9211b (4,500kg)I x Mikulin Ai\r1·5 turbojetproducing 4,4091b (19.6k )static thrustMach 1.7 at 23,000ft (7,000m)estimated72,OOOft (22,OOOm) estimatedUnspecified, probably forwardfuselage mounted cannons

I31 ft 2in (95m)215ft' (20m')II ft 6in (3.5m)3091b (140kg)5071b (230kg)I xBlackburn-Tomtit 18hp(13.4kW) piston engine85mph (137kph) approx24mph (40kph)

240ft (122m)

323ft' (30m')15ft 5in (474m)

I,3821b (627kg)1,9401b (880kg)I x Bristol-Lucifer 100hp (74.5kW)piston engine102mph (165kph)43mph (70kph)

BICh-3

BICh-7A

BICh-17

BICH-26

Armament

Middle: A small model of the B1Ch-17 fighter,equipped with large calibre APK recoillesscannons. This mid-1930s project was nevercompleted. Bill Rose Collection

Maximum speedLanding peed

LeFt: The tailless BlCh-17 fighter was specificallydesigned to carry two large-calibre recoilless APKcannons. A prototype of this aircraft was about60 per cent complete by February 1936 when theproject was scrapped on Stalin'S direct orders.Bill Rose Collection

CrewWing panWing areaLengthEmpty weightLoaded weightPowerplant

WingspanWing areaLengthPowerplant

CeilingArmament

CrewWingspanWing areaLengthGross weightPowerplant

Maximum speed

CrewWingspanWing areaLengthEmpty weightLoaded weightPowerplant

Maximum speedLanding speed

f\, ,, ,u", ,

"

nIIU

A Cheranovsky jet fighter design from WorldWar 2 that appears to belong to a different era.The designation of this futuristic concept isunknown. Bill Rose Collection

t32 Secret Projects: Flying Wings and Tailless Aircraft Soviet Tailless Designs 133

The full-sized twin-engineK-12 bomber prototypebuill at GAl State AviationFactory No 18 at Voronezh.The first test flight tookplace during July 1936.Bill Rose Collection

Designed primarily for sprayingpoison gas over enemypositions, the Stahl-5 was alsocapable of being used as a lightbomber and transport aircraft.Bill Rose Collection

Putilov's Attack Aircraft

Painted in spectacular markings, the K-12appeared at the Tushino Air Day Parade in August1937. Bill Rose Collection

In the early 1930s, several Moscow-basedengineers and designers formed a mallgroup to study steel airframes. Known as OOS(Russian abbreviation for Experimental Aeroplane Construction Section), the group washeaded by ergei Grigoryevich Kozlov andAlexander Ivanovich Putilov. They beganworking on a series of studies for bombers

power the K-12 with M-25 engines drivingvariable pitch propellers, but these were notavailable, so M-22 (licence-built BristolJupiter) nine-cylinder radial piston enginewere fitted rated at 435hp (324kW) continuous power, driving two-blade propellers.Because these engines were judged to beinad quat for the task, extensive weightsaving alt rations were made to the undercarriage resulting in the proposed electricallypowered retractable main wheels being fixedin position.

As a result, the take-off weight was loweredto 9,2591b (4,200kg) which allowed a maximum speed of 149mph (240kph), a ceiling of23,524ft (7, 170m) and a range of 435 miles(700km). Much of the airframe was fabricated from welded Chromansil steel tubingwhich was covered by fabric. Kalinin hopedthis aircraft would pave the way to animproved all-m tal variant called the K-14and a larger four-engine long-range taillessbomber with the reference K-17. Kalinin hadmade a number of enemies in high placeswho managed to delay the K-12 project andtried to have it scrapped. The situation finallychanged when K-12 was flown at the Augu t1937 Tushino Air Day Parade having beenrepainted in bright high-profile colours. Theaircraft made an immediate impression onsenior officials who ordered a resumption oftesting in early 1938 and requested preparation for production as a light-bomber.

Neverthel ss, Kalinin was arrested by thesecret police on trumped-up charge of spying. The 10 pre-production K-12s beingassembled were s rapped and his designbureau was disbanded. In 1940, Kalinin wasexecuted on orders issued by Stalin, althoughfinally pardoned during the 1950s afterStalin's death. As an aircraft, the K-12 was farfrom perfect with some reports indicatingthat it was often difficult to fly and sufferedwith various problems associated with tailless designs.

CrewWingspanWing areaLengthEmpty weightLoaded weightPowerplant

359ft (18m)783ft' (72.75m')26ft 3in (8m)6,7681b (3,070kg)9,2591b (4,200kg)2xM-22 (licence-built BristolJupiter)9-cylinder radial piston engineseachrated at 435hp (324kW)continuouspower

Maximum peed 149mph (240kph) at 9, 40ft(3,000m)

eiling 23,524ft (7,170m)Range 435 mile (700km)Take-off run 2,297ft (700m)Landing run 984ft (300m)Armament (production aircraft)2x 7.62mm ShKAS machine guns in no eand in tail turrets.I, I021b (500kg) bomb load in avertical rack

CrewWing panLengthWeight

This photograph shows the Kalinin K-12 gliderunder construction in 1934. The glider was used inthe development of the much larger K-12 taillessbomber. Bill Rose Collection

K-12

K-12 Glider

trailing edge with wingtip stabilisers and rudders. Construction was mainly from woodwith a fabric covering. It appears that sufficient space existed behind the pilot toa commodate an observer, although norecords confirm this. Following completionof the K-12 glider in 1934, the test pilot V.O.Borisov made more than 100 flights.

During 1935, work began on a full-sizedK-12 prototype at GAZ State Aviation FactoryNo 18 at VoroneZh, with the fir t test-flight taking place in July 1936 with Borisov at the controls. 46 flights were completed and theaircraft was then flown to Moscow in Octob r1936 for further trials that were undertak n bythe II's test pilot P. Stefanovsky. The K-12prototype had a wingspan of 59ft (18m). awing area of 783ft' (72.75m') and an overalllength of 26ft 3in (8m). There was provisionfor three crew members and positions for forward and rear manually-operated d fen ivemachine guns, although no weapon wereinstalled on the prototype. It wa intended to

civil aircraft. He submitted three different propo als to the NII-VSS (Scientific Test Institute)which were a conventional monoplane, atwin boom design and a tailless aircraft. Thetailless design was a epted on the groundof lower drag and reduced weight withKalinin receiving approval to develop a prototype that was given the reference K-12. Initially, there were wind tunnel tests withmodels and it was then decided to build ahalf-sized manned glider with a wingspan of29ft 6in (9.0m) and a length of 17ft (5.2m).The aircraft was equipped with a fixed undercarriage compri ing of two main wheels anda tailskid. Slats and ailerons were fitted to the

Kalinin's Flying Wing Bomber

Konstantin Alekseyevich Kalinin (1889-1940)was a Soviet engineer responsible for a numb r of interesting civil and military aircraftde igns during the interwar period. He beganhi career in 1916 as a military pilot and following several years in service, he attendedthe Moscow Air Force Engineering Academy.An xceptional student, Kalinin wa put incharge of an OKB during 1926 which wasprimarily responsible for developing civilaircraft.

In 1933, Kalinin produced plans for a newbomber that might also have potential as a

: ~ ~~ Tho ""Uo'o K-12 "'0",~ B,IIR~oCoII","o"


I32ft4~in (9.86m)249ft' (23.15m')14ft4in (4.365m)nspecified

I,3141b (596kg)I,6841b (764kg)I x hvet ov M-II 5-cylinderair-cooled radial engine producing100hp (747kW)108mph (174kph)53mph (85kph)15,900ft (4,850m)373 miles (600km)4hours

The small experimental BOK-5tailless aircraft was built in thelate 1930s and is said to haveperformed well and impressedthe professional pilots whoflew it. Bill Rose Collection

BOK-5

CrewWingspanWing areaLengthHeightEmpty weightGro weightPowerplant

and BOK-5 was quipp d with a fix d undercarriage compri ing two main wh els and atailskid. When completed, this compact aircraft had an empty weight of I ,3141b (596kg).

BOK-5 was completed at the b ginning of1937, buta number of late modifi ations wereintroduced, holding up night-testing until the

Maximum speedLanding speedCeilingRangeEndurance

BOK (Buro a ovikh Konstruktskii) atSmolensk was an OKB established in 1930 todevelop experimental designs and modify aviation equipment for special purposes. Havingproduced a small res arch aircraft calledBOK-2, the bureau was officially encouragedto begin work on a new design for a compactone-man Oying wing called BOK-5.

A team was assembled under the direction ofVladimir Antonovich Chizhevsky and fundingfor this project was made available in 1935.De ign work started almo t immediately andswiftly moved to the construction phase. BOK·5had a span of 32ft 4~in (9.86m) and a length of14ft 4in (4.365m). A Shvetsov M-II radial enginewas installed which produced 100hp (74.7kW)during cruise, with slightly more available during take off and it was coupled to a two-blademetal propeller. The airframe was mainly builtfrom aluminium alloy, the wing followed theCAHI (TsAGI) 890/15 profile and the fuselagesection was described as semi-monocoque indesign. Much of the aircraft's skin was fabric

BOK-5

470ft IO~in (216m)612.14ft' (56.87m')_5' 42' (outer wing leading edge)32ft (978m)Ilftllin(3.65m)13,2361b (6,004kg)23,2581b (10,672kg)2xMikulin (Tumansky) M-87Bupercharged 14-cylinder radial

engines, each producing 950hp(708kW)245mph at sea level, 303mph(488kph) at 17,057ft (5, 100m)90mph (l45kph)93mph (l50kph)27, 90ft (8,500m)I, 00 miles (2,900km), reduced to789 miles (1,269km) fully laden6xdefensive 7.62mm machineguns. 4,409lb (2,000kg) of bomb

Take·off speedLanding speedCeilingRange

CrewWing panWing areaWing weepLengthHeightEmpty weightGross weightPowerplant

Armament

DB-LK

During fast taxiing trials of the DB-LK in early 1940,Chief Engineer A. I. Filin ran over a tree stumpburied by snow on the edge of an airfield.The aircraft was quite badly damaged, but wasrepaired and testing resumed. Bill Ro e Collection

Maximum speed

conceivable that the DB-LK might have beenadapted to the reconnaissance role.

The ll-WS was now given the task of preliminary testing, but there were various difficulties encountered during taxiing trials andfinally a bad accident when Chief Engineer A.I. Filin hit a tree stump on the edge of the airfield that was buried by snow. This removedmost of the port undercarriage and damag dthe propellers beyond repair, although theaircraft itself was repaired and underwentvarious additional modifications. Testingresumed in 1940 with the DB-LK taking to theair. It is said to have performed well and as aconsequence, the aircraft was Oown aboveRed Square during the 1940 May Day Parade.

But there was considerable resistance tothe unorthodox design and a number of serious problems began to surface during thecontinuing trials, such as the rear gun positions being too close to each other. More worrying, were health issues ca'ised by engineexhaust fumes entering the fuselage andapparently, there was no imple solution tothis. Test pilots and engineers also complained about poor forward visibility from thecockpits. B Iyaev was now working on arevised design powered by two I,700hp(1,267kW) M-71 piston engines, but the project met with cancellation in late 1940.

the empha is shifting towards a military role.Belyaev now regarded his concept as a Oyingwing, although in the strictest sense it wasn'tthi , or even a tailless aircraft. In early 1938,Belyaev submitted plans for his bomber toTsAGI (Central Aerohydrodynamic InstituteRussia's equivalent to ACNNASA) atZhukovsky, Mo cow. The aircraft was nowcalled the DB-LK (meaning long-range Oyingwing bomber in Russian) and it won favourwith senior officials who informally approvedthe ass mbly of a mock-up and constructionof a prototype.

The DB-LK project was assigned the rathernon-descript reference 'Order 350' and it wasofficially approved in Defence ommitteeDecree No 248. A wooden mock-up wascompleted in the same year at Belyaev's KB-4Design Bureau in Moscow (Aircraft Factory156) and the prototype was authorised,reaching completion in September 1939. Thecircular fuselage sections and wing weremainly onstructed from aluminium alloy,with fabric covering some external areas. Thepilot Oew the aircraft from a cockpit in the leftfuselage section, which also accommodateda rear-facing gunner. The right fuselage section carried the navigator in a forward-facingcockpit and a rear-facing radio operator whoacted as another gunner.

Each fuselage section housed a forwardpo itioned Mikulin KB (later Tumansky)M-87B supercharged 14-cylinder radialengine (based on a Gnome Rhon design)providing 950hp (708kW) and driving aVISh-23D three-blade 10ft lOin (3.3m) propeller. The DB-LK had a wingspan of 70ftI O~in (21.6m), an overall length of 32ft(9.78m) and a height of II ft 11 in (3.65m).Flaps and ailerons were fitted to the wingsand there was a central tailfin with a rudderand a tailplane linked to the ailerons.

The aircraft was equipped with retractablemain wheels in each fuselage section and asingle tail wheel. At the rear of each fuselagesection was a completely glazed tail conewith a position for a single ShKAS 7.62mmmachin gun. The second crew member ineach fuselage section would operate thisweapon when neces ary and an additionalrear firing machine gun was propos d foreach wing's inner trailing edge. In addition tothe four rearward firing weapons, two ShKAS7.62mm machine guns controlled by the pilotwer positioned between the propellers inthe central wing section. There would be4,500 rounds available for all six guns. A bombbay was located behind each wheel housingand the possibility of carrying additionalbombs under the centre section (or perhapsextra fuel tanks) was considered. It is also

The unusual-looking DB-LKprototype flying wing bomberwhich was completed at theAircraft Factory 156 in Moscowduring September 1939.Bill Rose olleclion

Victor Nikolaevich Belyaev (1896-1958) was atalented Rus ian aviation designer whoevolved id as for a bat-wing aircraft duringthe 1920s and early 1930s. He believed that aOying wing designed with a small degree offorward sweep and a slightly curved backwould help to overcome longitudinal stabilityproblems and provide a notic able reductionof induced drag.

In 1933, some of Belyaev's theoretical workwas proven with trials of his BP-2 glider whichwas towed from th Crimean re ort of Koktebel (much favoured for early glider trials) toMo cow. The following year, he entered theAvianito Competition for a new transport aircraft submitting plans for an unusual twinfuselage aircraft capable of carrying 10passengers. The entry was unsuccessful, butBelyaev progre sively refined his design with

Oaps and a central aileron, plus two substantial stabilising fins with rudders that extendedbehind the trailing edge. In 1934, an experimental wing spar was completed and usedfor static testing, while a small proof-of-concept Stahl-5 demonstrator was buill andOovvn in 1935. Thi small tailless aircraft had aspan of 19ft 7in (6m) and was powered bytwo nine-cylinder Salmson 9ADB radialengines, each producing 45hp (33.5kW). It isnot clear if this was an unmanned vehicle orOown by a pilot, but it proved extremely difficult to control and the idea of building a fullsized prototype was finally dropped.

Belyaev's Db-LK

31

75ft5in (23m)I,292ft' (120m')41ft (125m)12, 1251b (5,500kg)17,640 Ib (8,OOOkg)2xM·34F V-12 water-cooledengines, each rated at 750hp(559kW)

nknownnknownnspecified bomb load. Could

carry tanks holding chemicalagents for disper al during night.


Putilov Stahl-5

-

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I ~~I (\

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CrewWing panWing areaLengthEmpty weightGro weightPowerplant

and transport aircraft which all rec ived thereference Stahl (Steel).

The most promising design was the Stahl-5,complet d in 1933. Stahl-5 was a tailless,transport aircraft or light bomber, also capable of praying poison gas. This was a twinengine aircraft with a thick central wingection and a Oush cockpit canopy positioned

at the leading edge. The wingspan was to be75ft 5in (23m) with a wing area of 1,292ft'(120m') and an overall length of 41 ft (l2.5m).A retractable undercarriage would be fittedand propulsion took the form of two M-34FV-12 water-cooled engines, ea h rated at750hp (559kW) driving three-blade, forwardmounted propellers. The airframe would bebuill almost entirely from Enerzh-6 stainlesssteel, with a Bakelite bonded veneer us d tocover the entral section and fabric in otherpart . The wing was equipped with slotted


I35ft 5in (10.8m)30ft 6Y.in (9.3m)34ft 9~in (10.6m)34ft lOY.in (10.64m)UnknownI x Klimov RD·45 turbojet(unauthorised Rolls-Royce enecopies), produced about 5,000 Ib(22.24kN) of static thrustUnknown2x23mm Volkov·Yartsev VYa·23t 2x20mm Berezin B·20 cannons

CrewWingspan (1947)Wingspan (J 948)Length (1947)Length (1948)Empty/gross weightPowerplant

Antonov 'M' Masha

Antonov's fighters w re soon ompletelyforgotten about.

Maximum speedArmament(both versions)

Top right: These drawings show the initial layoutfor the Antonov 'Masha' jet fighter (left) and thefinal configuration (right). Bill Rose Collection

Bollom right: An original Soviet drawing showingthe underside of the Antonov 'Masha' jet fighter.Bill Rose Collection

Bollom left: An illustration of the Antonov E-153glider, built and test flown during the unsuccessfulAntonov 'Masha' jet fighter project of the late1940s. Bill Rose Collection

Top left: This artwork shows an early configurationfor the proposed twin·engine Antonov 'Masha'jet fighter. Bill Rose Collection

in any surviving Russian documentation.The next stage in development of the revised

Masha was wind tunnel testing at TsAGI andonce this was successfully concluded, the construction ofa full-sized mock-up that could alsobe flown as a glider was approved.

Given the reference E-153, the mock-upwas built mainly from wood and equippedwith jettisonable wheels for take-off and askid for landing. Having been shown to officials in spring 1948, it was then prepared fortrials as a towed glider. Test pilot Mark L. Gallai was ready to undertake the first flight ofE-153 in July 1948, but the fighter project wasunexpectedly cancelled. It is believed that ajet-powered prototype of the 'M' had nowreached an advanced stage of construction,but this remains unclear.

Apparently, it was decided at a high-levelthat the La-15, MiG-15 and Yak-23 were sufficient for the country's immediate needs andany new combat aircraft would have to showa significant improvement over thesedesigns. Subsequently, the Masha and a number of other programmes were terminated.Antonov is known to have been disappointedby this decision and considered the Mashawell suited to future upgrades such asimproved engines and radar equipment. In1953, he designed another flying wing fighterpowered by AL-7F turbojets, but this neverprogressed beyond the concept stage and

highly classified, like every other Soviet military programme undertaken during the ColdWar era. The design was somewhat unusualin appearance, using two upright wingmounted stabilisers with rudder and forwardswept wingtip ailerons. A fully-retractable tricycle undercarriage was fitted with intakes forthe engines on each side of the cockpit. Proposed armament was four cannons located inthe nose and below the cockpit.

In late 1947, Project M was officially haltedand Antonov received instructions to redesignthe aircraft so it would accept the new RD-45engine. The RD-45 was superior in all respectsto the earlier engines, although it was a centrifugal design with a larger diameter, so theaircraft required extensive revision apart fromthe forward section. This resulted in a broaderfuselage with engine intakes at the leadingedge of the wing roots. Two upright stabilisingfins with rudders were fitted, but the outersection of the wing was now rounded withcontrol surfaces on the trailing edge of thewing. The wingspan was reduced to just over30ft (9.1 m) and the length was almost thesame as the earlier design at 34ft 10%in(l 0.64m). Armament also remained the sameas the 1947 version, along the undercarriagegear, although the rear wheels were positioned slightly differently. It is assumed thatthe cockpit was pressurised and an ejectorseat was fitted although this is not mentioned

360·70ft (18-2Im) estimate40-45ft (12·13m) estimateUnknown2x Klimov RD-45 turbojets(unauthorised Rolls-Royce enecopies), each produced about5,000 Ib (2224kN) of static thrustt500mph (t800kph) estimate40,000ft (12, 192m) estimateUnknown4,4091b (2,000kg) bomb load.2x 7.62mm machine guns in tail

CrewWing panLengthGross weightPowerplant

RKI

The name Oleg Constantinovich Antonov(1906-1984) is generally associated withtransport aircraft and not fighters, althoughduring World War 2, Antonov was Yakovlev'sdeputy and made numerous contributions tothe eVOlution of Yak fighters.

On 6 March 1946, Antonov took control ofhis own OKB (153) at ovosibirsk for thedevelopment of civil aircraft, but towards theend of the year, there was insufficient workfor his design team, so Antonov began to consider the possibility of building a new jetfighter. He had been impressed by the German Heinkel He 162A Salamander, praisingthe designer's straightforward, cost-effectiveapproach. This led Antonov to produce thebasic outline for a fighter that would be powered by a single RD-l 0 turbojet (Soviet copy ofthe Junkers Jumo 004B) mounted in a dorsalposition. He regarded this as a good configuration that avoided the ingestion of debriswhen op rating from poor sites. But Antonovis known to have expressed concerns aboutthe quality of Russian engines which were nomore reliable than the German originals andalso lacked power. In early 1947, he receivedofficial approval for the project and tests weresoon underway with wind tunnel models. ByApril, Antonov had been instructed to halt theprogramme and begin work on a flying wingdesign powered by two RD-l 0 turbojets.

Antonov now created the outline of anentirely new aircraft which was given thename Masha, usually abbreviated to 'M'. Chiefdesigners for this new project weI' A.A. Batumov and VA Dominikoviskiy, with I.I. Yegorychev being assigned responsibility fortooling and construction. Work continuedthroughout 1947 on the fighter, which was

Antonov M (Masha) Jet Fighter

Maximum peedCeilingRangeArmament

the RK I was formally cancelled in 1948. Soonafler this, Chetverikov's OKB was shut downand he accepted a teaching post in Leningrad.

, ,\ ....,1

type completed before the end of 1948.Details of this project have proved difficult

to locate, but available documents show thatthe RK-I would have been flown by a crew ofthree and carried a maximum bomb load of4,4091b (2,000kg) in a centrally-located bay. Itwas also intended to position two manuallyoperated 7.62mm machine guns in the aircraft's tail for defensive purposes. Propulsionwould b provided by two Klimov RD-45 turbojets, each producing about 5,0001b(22.24k ) of static thrust. These werereverse-engineered copies of the Rolls-RoyceNene centrifugal engine manufactured inRussia without UK approval.

Dimensions of the RK-l are not available,but comparisons with the British twin-engineCanberra bomber (initially tested with theNene engines before adoption of the Avon)and the Ilyushin 11-28 allow for some veryrough estimates. Wingspan of the proposedRK I was about 60-70ft (18-21 m), suggestingan overall length of approximately 40-45ft (1213m). It is also fair to assume that the designers were aiming at a maximum speed of atleast 500mph (800kph), but these figures arelittle more than guesses. A fin and rudderwould be mounted at each wingtip and control surfaces were positioned along the trailingedge of each wing. Lightweight alloy wouldbe used for most of the airframe and the aircraft was equipped with a fully-retractable tricycle undercarriage. The forward-positioned,fully-pressurised cockpit would have provided good visibility and this part of the designseems to have been adopted from thewartime Arado Blitz jet bomber.

It is not clear how far the RKI project progressed. Wind tunnel models were tested anda mock-up is believed to have been built, but

A tailless twin-jet engine light bomberdeveloped by Igor Chelverikov's Design Bureauduring the late 1940s. The project received thereference RK-I but never progressed farbeyond the drawing board. Bill Rose Collection

autumn. Test pilot I.F. Petrov was at th controls for the first flight, although he made ahard landing on his return and BOK-5 wasdamaged. Repairs and further modificationslasted for the remainder of the year and theBOK-5's handling characteristics were considerably improved. One of th se changesmay have been to the three control surfaceson each wing. In mid-1938, testing was undertaken by pilots from Il-WS, one of whom,P.M. Stefanovkii, is said to have remarked thatBOK-5 was very easy to fly. There were suggestions that experience gained from theBOK-5 could be used to build a n w longrange tailless bomber and a prototype wasprovisionally pencilled in as BOK-6. But theproposal went no further and in 1940, BOKwas absorbed by the Sukhoi OKB.

Russia's First Flying WingJet Bomber Proposal

Igor Vyacheslavovich Chetverikov (1909-1987)was officially requested to commence designwork on a jet-powered, twin-engine lightbomber in May 1947. His design bureau normally specialised in flying boats and it is unclearwhy the Chetverikov OKB was chosen to undertake this project. It has been suggested that thebureau was short of work and Chetverikov hadbeen allocated several German engineers withknowledge of Arado jet aircraft, but this explanation may be speculative.

Work on an engineering study of the proposed bomber was soon underway with a tailless, swept wing considered the best option.The aircraft was assigned the codename RK-Iand it was agreed that a mock-up would becompleted by the following year and a proto-


Th 0 B-LK advanced supersonicnytng \ Ing 011 ept developeddurlllg lh lale 1950s, but neverbuill. Bill R 011 ction

,k-l,

eight hours. Designed with a protruding nosesection, presumably housing optical sensors,this aircraft had a huge, although currentlyundisclosed, wingspan and was fitted withtwo upright inward angled tailfins with rudders. Intakes for the four jet engines are carefully positioned above the centre of the wingand just like the letterbox exhaust ports theywere designed with stealth in mind. A tricycleundercarriage was planned, but drawings donot indicate outrigger wheels that wouldappear necessary due to the substantialwingspan. Because an aircraft of this naturewould be a high-priority target in any surpriseattack, considerable attention was paid toreducing the radar cross-section (RCS) andthe M-67LK would probably use radarabsorbing materials (RAM) in many areas ofits construction.

M-67LK would loiter at altitudes of 66,00070,000ft (20,000-21 ,300m) for lengthy periodswithout detection, providing advanced warn-

Conceived during a highly-classifiedMyasishchev spyplane programmeknown as M-67, this large highaltitude stealthy aircraft was expectedto remain on station for periodslasting up to eight hours. It would bemanned by 10-15 personnel.Bill Rose Collection

found themselves under considerable pressure to improve their intelligence gatheringabilities and upgrade early warning systems.One result was a proposal to developspecialised high-altitude aircraft equippedwith state-of-the-art passive infrared sensorscapable of detecting missile launches andnew stealthy high-altitude manned andunmanned spyplanes. This project is thoughtto have started in 1984 with Myasishchevreceiving an urgent request from the Ministryof Defence to initiate a study which was giventhe reference M-67.

New types ofaircraft considered during thisprogramme were high-altitude manned nying wings and various highly sophisticatedlong-range unmanned aerial vehicles(UAVs). Many aspects of the M-67 projectremain secret, but the leading manneddesign was a large four-engine nying wingcalled the M-67LK (Cruiser) that was capableof accommodating a crew of 10 to 15 for up to

carrying bombs or air-to-surface missiles.Propulsion would be provided by two sets ofthree TRDF-VK-15M turbojet engines producing a total thrust of 34,8301b (155kN). Thiwould allow the aircraft to cruise at Mach 2.8while sustaining a maximum altitude of114,829ft (35,000m) and the range would beat least 10,000 miles (16,000km). Myasishchev was interesting in fully developingthis concept, but there was insufficient funding available to make it a reality due to strategic missiles and the space programme beinggiven priority.

The DSB-LK project was formally concludedin 1960, with research documentation beingprovided to the Myasishchev, Sukhoi andTupolev design bureaus. Some of this data issaid to have been used in the development offuture military aircraft such as the advancedMach 3.5 variable-geometry delta-wingedSukhoi T-4MS (200) that was designed in theearly 1970s but never built and the laterTupolev Tu-160 Blackjack supersonic bomber,which remains in Russian Air Force service.

There is little doubt that Soviet engineerscould have built the DBS-LK during the early1960s given sufficient funciing, but whetherthis aircraft would have met the intendedrequirements is questionable.

Late Cold War High-AltitudeSurveillance/ReconnaissanceProjects

East-West relations had reached a velY lowpoint when NATO Exercise 'Able Archer 83'began on 2 November 1983. This simulated amajor clash with Soviet forces in Europe andwhile it took place, NATO forces maintainedradio silence and only used highly-encryptedcommunication links. The exercise culminated with a DEFCON 1 alert and the authorisation to use battlefield nuclear weapons. Inthe lead-up to this exercise, concerns began todevelop within the Kremlin that the USplanned to use 'Able Archer 83' as cover for apre-emptive nuclear strike against Russia. Consequently, a decision was taken at the highestlevel to secretly bring Soviet nuclear forces tofull readiness. Tension continued to mountuntil the exercise concluded on 11 November1983 and Russia's strategic forces werereturned to stand-by. Little was disclosed to thepublic about this crisis during the remainder ofthe century and some details remain classified.However, many historians believe it was theclosest mankind has come to nuclear warsince the Cuban Missile Crisis of 1962.

'Able Archer 83' was clearly a major wakeup call for the Soviet armed forces which

2-3123ft 4in (37.6m)Cranked delta wing, swept 72'(approx) inboard and 42'oulboard170ft 7in (52m)195,1091b (88.5 metric Ions)660,000 Ib (299 metric Ions)6xTRDF-VK-15M turbojets,generating a total of 34,830 Ib(I 55kN) of thrustMach 2.8+114,829ft (35,000m)10,439 miles (16,800km)Four air·to-air missiles and twocannons.Up 10 11,0231b (15 metric tons) offree fall conventional and nuclearweapons, or air-to-surface missiles

DSB-LK Strategic Flying Wing Bomber

CrewWing panSweep

Armament (offensive)

LengthEmpty weightMax take-off weightPowerplanl

SpeedAttitudeRangeArmament (defensive)

1,102,290Ib (500 metric tons). The DSB-LKwould be powered by a number of advancedturbojets or turbo ramjet engines and the aircraft would carry a 33,0691b (I5,000kg)nuclear or conventional payload. Bymid-1958, the design had been extensivelyrevised. It would be powered by a combination of 6-1 0 turbojets and ramjets and the airframe would be mainly built from titaniumalloy. The maximum take-off weight wouldbe 660,0001b (299 metric tons), allowing amaximum speed of Mach 4.4 and a ceiling of114,829ft (35,000m). lt was also planned toequip the DSB-LK with defensive weaponsthat included four internally carried air-to-airmissiles with a range of6.3 miles (10km) andtwo cannons. In addition, there would beelectronic countermeasures and the Rubin-lradar system that was in development at thattime. lt remains unclear why some of thdefensive features were considered necessary, especially the cannons.

lt was now agreed that this aircraft was feasible using prevailing or near-term technology and it would be possible to build aprototype. Revisions continued into 1959 andthe DSB-LK was beginning to take shape as aviable design. The aircraft would be nown bya crew of three - the pilot, co-pilot and a navigator/electronics operative. DSB-LK now hada wingspan of 123ft 4in (37.6m) and an overall length of 170ft 7in (52m). The crankedwing would have an initial sweep of about 72°and a secondary sweep of 42°. Two largeupright swept fins with rudders were locatedabove the engine bays and ailerons werelocated on the wing's outer trailing edges.A multi-wheeled bicycle undercarriage wasplanned and the aircraft would be capable of

Although relatively little isknown about this four-engineflying wing bomber at present,the Ilyushin II-52 was probablydesigned to be comparable tothe US 6-47. Bill Rose Collection

""I'll1111\HJ

DSB-LK Strategic Flying WingBomber

In 1957, a project was initiated at the SovietMozhaisky Air Force Engineering Academy toproduce concepts for an advanced longrange supersonic nying wing bomber. Thename of this aircraft was DSB-LK (DalniyStrategicheskiy BombardirovshchikLetayushcheye Krylo - Long Range StrategicBomber - Flying Wing) and heading the project were the designers Alexander Moskalyovand A. Smirnov. While it might be argued thatthe DSB-LK is neither a true nying wing or tailless aircraft, it is sufficiently interesting to warrant inclusion in this chapter.

The idea was to develop an operational aircraft as opposed to an experimental prototype and the specifications were verydemanding. This was a significant projectand it involved several other academies, anumber of TsAGI departments and the Myasishchev OKB-23 design bureau. umerousconcepts were studied with the aim of producing a supersonic bomber with intercontinental range that would out-perform allexisting Western fighters and ny above thereach of surface-to-air missiles. Initial specifications for the DSB-LK were a requirement tocruise at a speed of Mach 2 and perhap havea maximum speed of Mach 4 while operatingat an altitude of about 114,829ft (35,000m).Estimates for take-off weight were

Ilyushin II-52 Flying Wing Bomber

This interesting design dates from the early1950s, although relatively little is knownabout it at present. It was a four-engine longrange jet bomber concept, probably intendedto match the capability of a Western aircraftlike the Boeing B-47. It would be designed tocarrying conventional bombs, probably anearly Soviet atomic weapon, or undertakereconnaissance operations. The bomb baywas located at the centre of the aircraft.

The II-52 would be supported on theground by a fully-retractable twin-wheel bicycle undercarriage with two outrigger wheels.The proposed wingspan was substantial andlengthy ailerons were proposed, although ithas not been possible to find details of anydimensions. Two upright stabilising fins withrudders were located towards the wingtipsand underwing pods close to these accommodate the outrigger wheels and might alsocontain extra fu I. One interesting featurewas the remote-control cannons located inpods at the centre of each main wing sectionto defend the rear. Propulsion would be provided by four turbojet engines located in acluster towards the tail, with air intakes oneach side of the fuselage just behind thecockpit. The type of engin considered forthis concept is unknown. Nothing came ofthe II-52 and it is probable that this design progressed little further than the drawing board.


OKL

ROCRRG

NGTE

RAERLM

Propul ion of ir raft projectational G Turbin Establishment

(UK)NM Nautical Mile (I M =1.15mile)Nurflugel German term for wing nlyaircraftOKB Opytnoe Konstruktor ko Byuro

Soviet Experimental 0 ign Bur auOberkommando d r Luftwaff(Luftwaffe High Command)

Payload Normally cargo or equipment, but canrefer to military ordnanceRoyal Aircraft EstablishmentReichsluftfahrtsministerium (wartimeGerman Air Ministry)Royal Observer CorpsRh6n-Rossitten Gesellschaft - earlyGerman gliding society. In 1933, RRGbecame the DFS

ALT I Strategic Arms Limitation Treaty 1SBAC Society of British Aircraft Constructors

enior Citizen Codename for classified USstealth transport aircraft

SNCASE Societe Nationale de ConstructionsAeronautiques du Sud-est. France

Stealth Low-visibility technologiesSTOL Short Take-orf and LandingTechnische Luftriistung German wartime

Technical Air Armaments OfficeTFW Tactical Fighter WingTons/tonnes Throughout this book the value

for 'ton' equates to an American shortton, which equals 2,000 lb. The metrictonne is I ,000kg, and the conversionfactor is 0.9072

TsAGl Tsentrahl'nyy Aero-iChidrodinameeches!?iy Institoot (CentralState Aerodynamic and HydrodynamicInstitute), Zhukovsky

UCAV Uninhabited Combat Air VehicleUSAAF United States Army Air ForceUSAF United States Air ForceVolksjager German wartime People's Jet

FighterVTO Vertical Take-OffVTOL Vertical Take-Off and LandingWalter Rll-203b rocket engine fuel

T Stofr: Concentrated hydrogen peroxideZ Stoff: Calcium permanganate liquid catalystC Stoff: Methyl alcohol, hydrazine hydrate andwater mixture catalyst (replaced Z Stoff)

WSMR White Sands Missile Range

ANP

BLTBuAerBWBBTZ

BLC

ATBAFBAFEE

AAMALBE

Glossary

DFS

000FE

MoSMtNACA

NASA

ir-lo- ir Missilemm lri ,Load-Balanced Exhaustzzl

dv n dTAir F r BAirb rn Frs 'p rirnentalE tabli hm nt, h rburn-in-Elrnet,York hir1950 SAF Air raftprogramm

BAC British Air raft orpBAT Baynes Aerial TankBlack Projects Highly- la sifi d, r lIy-

funded prograrnmes u ually involvingthe development of new militarysystems. These can r main hidd n f ryears, perhaps decades, om timeprogres ing no further than studi .Boundary Layer Control, a m thod ofdrag reductionBoundary Layer TheoryUS avy's Bureau of AeronauticsBlended Wing Body aircraft designBureau Technique Zborowski.An aircraft design organisation,operating in post-war France andheaded by Dr H Imut Zborowski

CIA Central Intelligence AgencyDARPA US Defen e Advanced Research

Projects AgencyDeutsche Forschungsanstalt furSegelflug - German Research Institutefor Soaring FlightUS Department of DefenseUS WW2 prefix for Foreign Equipmentserial number

KTS Knots (I knot = 1.5mph)Laser Light amplification by stimulated

emission of radiation - monochromaticvisiblejinvisibl light

Luftwaffe German Air ForceMoA UK MinistlY of Aviation, 1959-1967MoD UK MinistlY of Defence, 1964-Present

DayUK Ministry of Supply, 1939-1959MegatonNational Advisory Committee forAeronautics

ational Aeronautics & SpaceAdministration

NEPA US post-war uclear Energy for the

tude reconnaissance aircraft using passivesensors and linking to a ground station via asecure orbital relay platform. There is also thepossibility that the M-67LK-M was derivedfrom a Myasishchev study to match America'sB-2A stealth bomber.

Other proposals for M-67 include a fairlyconventional looking manned aircraft with along, straight wing and what appear to be tandem cockpits. Powered by two jet engines, itwould carry a large sensor pod above the centre of the wing. This design may be known asthe M-67VDS. Two unmanned high-altitudeproposals include a single-engine swept-wingaircraft referred to as the M-67 Boomerangcarrying side-looking optical equipment in thenose. This UAV could be quite substantial insize and utilises a tricycle undercarriage. Thewing has a similar profile to the mannedM-67LK-M and in addition to elevons there aresmall wingtip fins that may be rudders.

A second long wing UAV would performthe same role as the Boomerang, but appearsto have been designed from the outset tohave a very low radar cross section. Designated as the M-67BVS-LK, this aircraft has asmoothly contoured rounded and flattenednose leading directly to the wings. Above this,is an upper fuselage section containing forward-positioned windows for side-lookingoptical equipment. A single jet engine contained in the rear of the fuselage draws airfrom two rectangular air intakes just behindthe sensor windows and the exhaust outlet ishidden by two inward-leaning fins with rudders. Control surfaces are located on theouter trailing edges of the wing and the aircraft is supported on the ground by a fullyretractable tricycle undercarriage. Nothingelse is currently known about this fascinatingprogramme, which presumably ended withthe economic collapse of the Soviet Union.

Above: This M-67 Myasishchev design (thought tobe M-67LK-M) from the 1980s bears a degree ofresemblance to some proposals for America's ATB(eventually the Northrop B-2A). The design isclearly stealthy, having carefully-configured engineintakes and exhaust ports and most of the exteriorwould be covered in RAM (Radar AbsorbingMaterial). The primary purpose of this aircraftwould be to look for unannounced missilelaunches using state-of-the-art, passive infra-redsensors. However, it seems likely that Myasishchevalso considered this design as a reconnaissanceaircraft or bomber. Bill Rose Collection

Left: This unmanned proposal for the M-67 projectis believed to have been assigned the referenceM-67BVS-LK. It would loiter unobserved at veryhigh altitudes for extended periods of time, usingpassive optical equipment to look for signs ofNATO missile launches and provide advancedwarning of a pre-emptive attack. Bill Rose Collection

no vertical control surfaces. The leading edgesweep is about 36° and the extended wingsection had a constant chord with flaps andelevons. Four jet engines power the M-67LKM and there are stealthy dorsal air intakesbehind the cockpit area and carefullydesigned rectangular exhaust ports.

Dimensions, weights and performance ofthis aircraft are unknown, although it wouldemploy a multi-wheeled tricycle undercarriage. On the upper rear of the fuselage is asubstantial teardrop-shaped pod for unspecified purposes, perhaps containing opticalsensors, although the exact role of this aircraftis unclear. It may have been intended toundertake the same missions as the previously described M-67LK Cruiser, or it mayhave been proposed as a stealthy high-alti-

~! I

ing of missile launches at times of heightenedtension. Equipment carried by the aircraftwould have been designed to recogniselaunches of theatre ballistic missiles such asthe newly-introduced super-accurate US Pershing II stationed in West Germany. An abilityto detect and track long-range strategicnuclear missiles would also appear to be partof the M-67 project and this aircraft may havebeen considered for the role.

A second very different Myasishchevmanned aircraft bears some resemblance toearly proposals for America's ATB (eventuallythe Northrop B-2A) and also suggests a goodawareness of US military developments. Thedesignation of this concept appears to beM-67LK-M and very little is currently knownabout it. The design is a pure flying wing with

===========::::(~C:::I===========


AD-I NASA Oblique Aircraft /27-/28Aerojet XCAL-2oo Rocket Engine 9/Aerojel Liquid Fuel Rocket Engine 89, 90Airborne Forces E.xperimental Establishment

(AFEE) /2Alan Muntz ompany /2Allison J3S-AI5 Turbojet 79Allison V-3420 Engine 75Allison XT40 Turboprop Engines 84Amerika Bomber 5/,53Andrews AFB 8/ANI': USAF uclear Propulsion Programme

87,98Antonov M (Masha) Jet Fighter /38-/39Arado Ar I 36-37, 98Arado E.555-1 to E.555-15 35-36Arado E.58 1-4/5 36Armstrong Whitworth AW.50 /6-/9Armstrong Whitwortll AW.52 /9-20,3/Armstrong Whitworth AW.52G /7-/9Armstrong Whitworth AW.56/9-2/, 26Armstrong Whitworth AW.1712/Armstrong Whitworth MkVII Light Tank

Tetrarch /2, /3Arnoux, Rene 6, 7ATA: Advanced Tactical Aircraft (A-12A

Avenger) /06-/08, /2/, /28ATB: Advanced Technology Bomber ///-//2,

/42Avro Vulcan 7, 8, 2/, 26-27, 83

B-2A Northrop-Grumman Spirit 8, //2-//9B-3 ext Generation Bomber /2/-/22BAT: Baynes Aerial Tank /2-/3Baynes, Leslie Everett (1902-1989) 1/-/3Belyaev, Victor Nikolaevich (1896-1958) /30,

/36-/37Bishop, Ronald 2/Blohm und Voss Ae 60739Blohm und Voss BV 1'.20837Blohm und Voss 1'.210-01 BV37-38Blohm und Voss 1'.212 BV 38-39,4/Blohm und Voss 1'.215 BV 39Blohm und Voss 1'.21739Blohm und Voss Shipbuilding Company 37BMW Strahlbomber II 40Boeing B-IR /22Boeing F/A XX /23Boeing Model 306 Bomber 70Boeing Model 306 Flying Boat 7/Boeing Model306A Airliner 7/Boeing Model306B Fighter (Single Engine) 7/Boeing Model 306C Fighter erwin Engine) 71Boeing XB-15 70Boeing X-45 Programme /22BOK (Buro Osovikh Konstruktskii) 5 /37-138Bouncing Bomb Project (UK) /3, 27Brandis Airfield 45, 49, 58-59Bristol Cherub Engine 10Brown, Captain Eric Melrose 'Winkle' /3, /5,

62Burnelli, Vincent (1895-1964) 7,75,87, /23Burnelli Flying Wings 75Butler, James William 6BWB: BI nded Wing Body Aircraft /23-/26

Carden, Sir John //Carden-Baynes Aircraft 1/Cardenas, Major Robert 8/Cayley, Sir George (1773-1857) 6Chadwick, Roy(1 93-1947)26-27Chance Vought Aircraft at Stratford,

Connecticut 98hance Vought XF7U·I Cutlass 98-99

Cheranovsky, Boris Ivanovich (1896-1960)/30-/33

Cheranovsky Advanced Jet Fighter /32, /33Cheranovsky BICh-2 /30Cheranovsky BICh-7 /3/Cheranovsky BICh-14 /3/Cheranovsky BICh-24 /33Cheranovsky BICh-26 /33Chetverikov RK-I /38

hillese Embassy (Belgrade) BombingIncident 1999//4, //6-//7

onsolidated Aircraft Flying Wing Bomber 73Consolidated-Vultee 2 Eng Patrol-Bornber

85-86Coplin, John 25

IndexCornwall, George (1897-1960) 29

Crosby, Harry 89-92unningham, John (1917-2002) 23

da Vinci, Leonardo (1452-1519) 6Dams, Ruhr, Germany, Mohne, Sorpe & Eder

27Davies, Stuart 26DB-LK Bomber /36-/37de Havilland, Geoffrey Roald OBE (1910-1946)

22de Havilland DH.108 Swallow 2/-23, 62, 69, 93de Havilland Gipsy Major II 4-cylinder Piston

Engine /4Derry, John (1921-1952) 23DFS: Deutsche Forschungsanstalt fur Segetnug

34, 35, 53, 54DFS 19454-55Dittmar, Heinrich 'Heini' 55,56,58Dornheim, Michael A. 1/2DSB-LK Strategic Flying Wing Bomber /40-/4/Dunne, John William (1875-1949) 6, /0

Edwards, Edmund 6Edwards, George 26Edwards, Glenn (1918-1948) 8/Egypt Bay near Gravesend, Kent, Accident

Scene 23EHK: Enlwicklungs-HauplKomission 35Espenlaub, Gottlob 34Etrich, Igo (1879-1967) 6

Falk, Iloland 'Iloly' (1915-1985)27, 62Focke-Wulf Fw I000 x 1000 x 1000 Bomber 40Forbes, Daniel Hugh (1920-1948)8/Franklin, Eric /9

GAL: General Aircraft Ltd 9, /3-/6Genders, Squadron Leader George 23General Dynamics Cold Pigeon /06General Dynamics-McDonnell Douglas A-I2A

Avenger 118, /05General Electric F-118-GE-looTurbofan

Engine //4, //6GLAS: Gust Load Alleviation System //4Glenn L. Martin Company 76Goblin 2 Turbojet Engine 2/Goring, Ileichsmarschall Hennann 43,45,5/Gotha Waggonfabrik A.G 46, 48Gotha Go 229A 46, 48Gotha P.60A 48GRD-2M-3V Rocket Engine 65Green Lizard 28Gunter, Siegfried (1899-1969)4/-42

Handley Page HP.75 Manx /3-/4Handley Page HP.117 3/-32Harper's Dry Lake, Lockhart, California 9/Hartley Winlney, Hants, Accident Scene 23Hawker-Sidd ley 1'.1077 Tailless Two-man Jet

Fighter25Heinkel Hirth He SOil Turbojel35Heinkel P.I078NB/C Fighters 4/Heinkel 1'.1080 Ramjet Fighter 42Henschel, Friedrich icolaus 43Henschel 1'.13542-43Hertel, Dr Heinrich (1902-1982) 53-54, 60Heston JC.9 29Hill, Geoffrey Terence Roland (1895-1955)

10-//Hill Pterodactyl Bomber 10-//Horten, Reimar (1915-1994) 7, 34, 43, 46, 49

52,72Horten, Walter (1903-1998) 7, 34, 43, 45, 49-52,

72Horten Ho VIt 43Horten Ho IX Fighter 43, 45-49, 5/, 52, 66, 96, IIIHorten Ho X 49-50Horten Ho Xilia Glider 50Horten Ho Xilib Fighter 50Horten Ho XVlllb 52

Ilyushin II-52 /40hlStitutO Aerote nico at C6rdoba 52

Jones, Dr Robert Thomas (1910-1999) /27-/28Junkers, Hugo (1859-1935) 6-8, 34Junkers EF.12824, 53

Junkers EF.130 53Junkers Ju 24860

Kalinin, Konstantin Alekseyevich (1889-1940)/34-/35

Kalinin K-12 Bomber /35Kalinin K-12 Test Glider /34Kauba, 011037Klimov RD-45 Turbojet /38-/39Kozlov, Sergei Grigoryevich /35Kronfeld, Robert (1904-1948) /2, /3, /5, /6

Lachman, Dr Gustav Victor (1896-1966) /3Laute, Dr W. 35Lean, David 23Leuna Synthetic Fuel Plant 59Lilienthal, 0110 (1848-1896) 6Lindley, Bob 26Lippisch, Alexander Martin (1894-1976) 7,26,

34-35, 4/, 50-5/, 54-57, 59, 62, 65-68, 93, /00Lippisch Li P.04-106A 65Lippisch 1'.0965Lippisch 1'.1065-67Lippisch 1'.11 65-67Lippisch 1'.1557-58Lippisch Delta VI 66-67lillie Brickhill, Buckinghamshire, Accident

Scene 23UOl'd, John 'Jimmy' (1888-1978) /6-/7, /9Lockheed CL-187-3/02-/03Lockheed CL-278-1-2 95-96Lockheed CL-1170 /04-/05Lockheed CL-1201 Atomic Powered Aircraft

96-98Lockheed F-117A8, /06, I/O, 1/7Lockheed Gusto 296Lockheed L-248-3 Atomic Powered Bomber

87Lockheed Senior Peg /09-///Lockheed Martin A /APR-50 (also known as

the ZSR-63) Radar Waming System //5Lockheed-Martin FB-22 /22-/23Lockheed~Martin ext Generation Bomber

/2/Lockheed-Martin X-44A /22Lusk, Arthur 93Lycoming R-680-13 Radial Engine /4

M22 Locust Light Tank (US) /3Martin XB-16 70Matsu 1~29, Japanese Diesel Electric

Submarine 60Messerschmill Me 163A 55-58Messerschmill Me 163B 22, 49, 55-65, 93Messerschmill Me 163C 57-60Messerschmill Me 263 50, 64, 65Messerschmill Me 329 67-68Messerschmill 1'.08.01 68Messerschmill 1'.1108.11 69Messerschmill 1'.1111 69Metropolitan-Vickers (Metrovick) F.2/4 Beryl

Turbojet 17MiG 1-270 (Zh) 64-65MiG Stealth Bomber //8Mikulin (Tumansky) M-87B Radial Engine /36,

/37Mitsubishi J8M I Shusui 6/, 63Mk3 Atomic Bomb (US) 8/, /02Mk4 Atomic Bomb ( S) 8/Mouillard, Louis Pierre (1834-1897) 6Muller-Rowland, Squadron Leader Stuart

(1921-1950) 23Multhropp, Hans 62Muroc Field (now Edwards AFB) 62, 63, 75, 76,

79,8/,82,88,90,9/,92,93Myasishchev M-67 //8, /4/-/42

National Advisory Committee for Aeronautics( ACA-theforerunnerof ASA) /0,3/,32,

65, 75, 89, 90, 93, 94, 98, /27, /36National Air and Space Museum (US) 46, 63,

88,89National Physical Laboratory at Teddington,

Middlesex 28Northrop, John 'Jack' Knudsen (1895-1981) 72Northrop B-49 7, 8, 79-8/,83,84, //2Northrop MX-324 89-9/Northrop MX-334 89-9/Northrop -IM9, /6, 72, 73, 75, 76,87,88

Northrop N-9M 75-77Northrop N-381 /03-/04Northrop Senior Ice /09, III'orthrop Swilchblade /29

Northrop Turbodyne V 83-84Northrop X-4 93-94I orthrop XB-35 75-80, 84I orthrop XP-56 Black BUllit87-90, 92I orthrop XP-79 89-93Nortllrop XP-79B 9/-92I orthrop YB-35 76, 78, 79, 8/Northrop YB-49 78-85Northrop YRB-49A 82,83Northrop-Grumman B-2A Spirit Stealth

Bomber8, 5/, 68,76, /06, /07, III, //2-/22Northrop-Grumman B-2C //7

orthrop-Grumman EB-2A //7Northrop-Grumman RB·2A I J7Northrop-Grumman Next Generation Bombl"8,9, /2/-/22, /28-/29

Oblique Flying Wings /26-/29OKB: Opylnoe Konstructorskoe Byuro(Experimental Design Bureau) 63-65, /34, 1.J7

/38, /40, /43Operational Requirement 0R.229 /9-20,26Operational Requirement 0R.246 24

Peenemunde-Karlshagen 55, 58Penaud, Alphonse (1850-1880) 6Prall & Whitney Wasp Major Radial Engine 71Predannack Aerodrome, Cornwall 28, 29Pterodactyl Aircraft 10-//Putilov, Alexander Ivanovich /35Putilov Stahl-5 /35-/36

Raytheon AI APQ-181 Covert Strike Radar IIIReitsch, Hanna (1912-1979)34, 58Rockwell B-1 B bomber 29, 30, 11/, 1/3, 1/7,

/2/, /22Rolls-Royce \/TOL aircraft 25

Scud I Light Sailplane //Senior Citizen //9-/20SG-5oo Jagdfaust (Fighter Fist) 59, 60

hort PD.762Shvetsov M-II Radial Engine /37Skoda-Kauba SK V-637, 38Slingsby Sailplanes /2SNCASE SE. I 800 54Specification N.40/46 (UK) 24-25Symington, USAF Secretary Stuart 84-85

T-IO 12,000 Ib (5,443kg) Bomb 80T-14 22,000 Ib (9,979kg) Bomb 80Tailless Aircraft Advisory Commillee (TAAC')

/0, /4Talbot, James Richard (1909-1945) /3, /4

UCAS-D Carrier Based CAV Project /08, /2//22,123, /28

Vickers Swallow 9,27-3/Vogt, Dr Richard (1894-1979) 37-39, /26Vought F-8 Demonstrator /28

Wallis, Sir Barnes Kt, CBE, FRS, RDI, FIlAeS(I 7-1979) /3,27-3/,80

Walter HWK 109-509C Rocket Engine 60Westinghouse 19-B Turbojet 9/, 92Westinghouse J46 Turbojet 99, /00Westinghouse XJ30WE-7 Turbojel93, 94Westland PJD.14424-25Wild Goose 28-29\Vilde, Geoffrey Light (1917-2007) 25Wilson, Captain Jennifer USAF //7\Vinter, Martin 62Wood, Donald 26Wright, Edgar Alexander 'Ginger' (1914-1940)

/3, /4Wright, Orville 34Wright-Patterson AFB, Ohio 62, 70,8/,82,8'1.

94, 95, 96, 1/9

X-47B Pegasus UCAV /2/

Yokosuka MXY8 Glider 6/Yuganov, Victor (1922-1964) 65

Ziller, Leutnant Erwin 45

144 Secret Projects: Flying Wings and Tailless Aircrafl

R041 MiG Stealth

G045 Komet

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