XV. Airship Types in the PostwarPeriod

The airships employed by the Navyafter WW II included the operating typesused in the war, as well as some modifiedand several new types/classes. The Gand L-types were used briefly in thepostwar period. By 1947 all of the L-typeshad either been sold, stricken or placed instorage. Some of the G-types were still inservice with the Naval Airship Trainingand Experimentation Command in 1947.

During WW II the designations thatapplied to these four airship classes wereZNP-K for the K-types, ZNN-G and ZNN-Lfor G and L-types and ZNP-M for the M-type. In 1947, the Navy’s General Boardmodified the airship designation systemby dropping the “N” which stood for non-rigid. This was done because the boardhad scrapped the rigid airship program.A f t e r t h e “ N ” w a s d r o p p e d , t h edesignations became ZPK, ZTG, ZTL (Twas used for training vice N) and ZPM.These changes were published in April.

The first modernized K-type airshipswere designated ZP2K. On August 7,1951, a ZP2K, equipped for longendurance flights with in-flight refuelingequipment and attachments for pickingup sea water as ballast, was delivered tothe Navy. The second modification to theK-types led to the designation ZP3K. Thefinal configuration of the ZP3K was flownon November 12, 1952, and accepted atNAS Lakehurst. The airship was updatedfor ASW operations and was designedespecially for carrier-based operation.There were 30 ZP3Ks.

A new-type airship was ordered fromGoodyear in 1951 under contractnumber 51-657. She was designatedZP4K but was of a different design thanthe original K-type. The new designreflected an increased concern for ASWbecause of the Korean War.

The first one was delivered to the Navyin June 1954, and 14 more eventuallyfollowed with bureau numbers 13191-131926 and 134019-134024. A ZP4Kwas later fitted with a dacron envelopeand flown at Lakehurst.

The follow-on to the ZP4K was a newlydesigned airship designated ZP5K andordered on contract number 52-985 in1952. The first one was delivered in May1955. A unique feature was the inverted“Y” configuration of the tail structure.The Navy received a total of 12 ZP5Kswhich were assigned bureau numbers

Top right, in a reversal of roles, a U.S. submarinegoes to the assistance of an updated K-class

airship that was disabled during an ASWexercise in 1952. Right, while operating with

an escort carrier such as the USS Kula Gulf(CVE-106), airships were capable of

conducting at sea replenishment of stores and fuel.

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141564-141570, 144239-144241 and146294-146295.

In 1954, a major change occurred inthe designation system for airships. Itwas similar to the system the Navy usedfor its other aircraft. The difference wasthe inclusion of the builder’s initial in theairship’s designation. The changes wereas follows: ZP2K became ZSG-2; ZP3Kbecame ZSG-3; ZP4K-ZSG-4; ZP5K-ZS2G; ZPN-ZPG-1; ZP2N-1 - ZPG-2; andZP2N-1W - ZPG-2W.

One of the characteristics of the Navy’snon-rigid airships over the years hadbeen the letter-class identification of “N”for non-rigid. It is fitting that the story ofthe last airships operated by the Navywere initially given the class designationof “N.”

XVI. LTA Records Set in the 1950s

The story begins with the success ofthe K-class airships in WW II ASWoperations. This diminished the need forthe much improved M-class of the lateWW II period, only four of which werebuilt. Following the war, it was clear thatthe improved versions of the K shipscould handle many LTA tasks. However,with the installation of radar, towedsonar and other new ASW systems, inaddition to the need for greater patrolranges, there was a need for ships largerthan the M-class.

In 1947, the Bureau of Aeronauticsinitiated a design competition for a largerASW airship to incorporate the newrequirements. Goodyear and Douglaswere contenders. The Navy purchasedthe Douglas design, but subsequentarrangements led to Goodyear buildingthe new Nan ship.

Initial go-ahead in 1948 covereddesign engineering, mock-up and aground test propulsion system. TwoWright R-1300-2 air-cooled engines,mounted in the car, drove two reversible-pitch propellers on outriggers, withclutches and transmissions so that eitherengine could drive both propellers, oruse both engines. While this workproceeded, the contract for the ZPN-1prototype was signed. It would be thelargest nonrigid airship built, with an875,000-cubic-foot envelope, a double-deck car with ample provision for the 14-man crew, extensive ASW equipmentand in-flight refueling capability forex tended opera t ions re fue led byaccompanying Navy ships.

In January 1950, the ground test rigwas running, but even this lead wasn’tenough when transmission difficultiesencountered later in the year delayed thef i rst f l ight into 1951. Meanwhi le,production versions were ordered as theZP2N-1, which had many improvements,

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including a larger envelope of 1,011,000cubic feet.

The ground rig resumed running inearly 1951, with power plant installationin the N-1 in April, and first flight in June.It was soon realized that the ballonetswould have to be replaced because offabric characteristics, but this waspostponed until after the Board ofInspection and Survey (BIS) trials. Late in1950, flight testing was interrupted formodifications, including increased finstrength and reduced control systemfriction.

Early 1952 saw final solution of the findesign problem, with tail surfacesfurther modified for final tests at Akron,followed by June delivery to Lakehurst,and Navy Preliminary Evaluation (NPE) inJ u l y . T h e N P E r e s u l t s w e r edisappointing, particulary in the airship’sperformance and further tests followedto explore specif ic improvements.Meanwhile the first production ZP2N-1was approaching completion and anAEW version of the N-type, the ZWN-1,was begun. Activity came to a halt atGoodyear during a fall strike, and the firstZP2N-1 did not fly until May 1953. By thistime the ZWN-1 had been redesignatedZP2N-1W, a prototype ordered, and firstflight scheduled for September 1954. Itwould feature larger radar antennas

Right, postwar airships, including ZP4Ks(later designated ZSG-4s) and ZP5Ks (laterdesignated ZS2G-1s), in their hangar at NASGlynco, Ga., 1956. The rear left and frontright airships are the ZP5Ks. Below, a newpostwar airship, designated ZP5K (laterredesignated ZSSG-1), operates withUSS Franklin D. Roosevelt (CVA-42) nearGuantanamo Bay, Cuba, in 1956.

inside the envelope than could bemounted externally without excessivedrag.

Lakehurst operations with N-1 andflight testing of the ZPPN-1 at Akroncontinued through spring, summer andinto fall. Mock-up inspection of the -1Wtook place in May. While the flights of N-1 showed the potential of the Nans, theyalso confirmed the need for the largerenvelope, as in the case of the ZP2Ns. InNovember, N-1 was deflated for theb a l l o n e t r e p l a c e m e n t , a n d w a ssubsequently overhauled and rebuiltw i t h a l a rge r 975 ,000 -cub i c - f oo tenvelope.

After a delay to correct a transmissionproblem, the first ZP2N-1 was deliveredto Lakehurst late in the year for Navyt r ia l s . A ba l lone t fa i l u re , due tooverpressurization in January 1954,required corrective action to thepressure system, but the fourth ZP2N-1was delivered that month. Spring sawthe first APS-20B installation in the fifthship, with BIS trials of the new radar atLakehurst. The airships were alsoredesignated at about this time, with theNs becoming ZPGs. The ZP2N-1 and 1Wbecame ZPG-2 and 2W, respectively. Thefirst fully-equipped ZPG-2 was deliveredfrom Akron to the fleet for operationaluse in July.

BIS trials of the ZPG-2 were completedin December, and ZX-11 began extendedoperational trials early in 1955, whileanother ZPG-2 went to Naval AirDevelopment Unit, South Weymouth,Mass . , fo r a l l -wea ther tes ts w i themphasis on extreme winter-weatherconditions. The first flight of the ZPG-2W

In the foreground is the N-1 airship, the prototype for the Navy’s last great series of airships designed for long-range patrol. A K-type airship is inthe background.

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early in the year coincided with increasedinterest in the use of nonrigid airships aspart of the national early warningne two rk . The ZWG-1 , des i gnedspecifically for this mission, was orderedbut was subsequently replaced by amuch-modified ZPG design as the ZPG-3W. Larger radar antennas wereinstalled inside the 1,516,000-cubic-footenvelope, while the higher-poweredWright R-1820-88 engines werereturned to external nacelles.

With the first ZPG-2W delivered toLakehurst in May, production andoperation of the ZPGs continued,interrupted by a suspension cable failureproblem that resulted in grounding theships for replacement with redesignedcable assemblies during the summer. Byend of the year, the mock-up inspectionof the ZPG-3W had been completed, aswell as first delivery of a ZPG-2W to ZP-3.

Before the ZPG-3W made her firstflight in July 1958, production of the 12

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ZPG-2s and five ZPG-2Ws purchased hadbeen completed and the -2s had set anumber of records for extended-durationf l i g h t s . F o u r Z P G - 3 W s w e r esubsequently delivered, but a fatalaccident to the first one at sea in thesummer of 1960 and a change in earlywarning mission left the ZPG-2s as themajor LTA long-endurance aircraft.

Operations continued into the fall of1961, when all fleet operations wereended. Two research and developmentZ P G - 2 s c o n t i n u e d t h e i r s p e c i a lassignments as a flying wind tunnel andan ASW research laboratory throughAugust 1962, and then all Navy LTAoperations came to an end.

The Navy ’s las t a i rsh ips weresophisticated vehicles and lighter-than-air advocates of the day believed them tobe competitive with other airbornevehicles in the Naval Aviation inventory,particularly in the areas of airborne earlywarning (AEW) and antisubmarine

The moored airship is a ZPG-3W, the largestnon-rigid airship built in the world. It wasthe last type of airship the Navy built beforebringing a close to its LTA era in 1962.Directly above the ZPG-3W is a ZPG-2W.Both of these airships were designed forairborne early warning duties. In thebackground is a postwar K-type airship.

warfare. One of their strong points wasthe ability to remain in the air for longperiods of time. Every opportunity wastaken to demonstrate th is uniquecapability and in the process many newrecords were established.

The first of these was set in May 1954.A ZPG-2 airship under CommanderMarion Eppes departed NAS Lakehurstfor an endurance flight which took hernorth to Nova Scotia, east to Bermudaand then south to Nassau, the CaribbeanSea and the Gulf of Mexico. The airshiplanded at NAS Key West on May 25 with

an elapsed time of 200.1 hours in the air.It was a notable achievement and Cdr.Eppes was awarded the HarmonInternational Trophy for his achievement.

At about this time, the Chief of NavalOperations ordered a series of tests toevaluate the all-weather, continuous-patrol capabilities of the airship. Thesefeatures were of particular concernduring the 1950s because the U.S. wasseeking a reliable, high-endurance AEWplatform which could detect incomingenemy bombers.

Beginning January 14, 1957, acontinuous patrol was maintained for 10days, 200 miles off the coast of NewJersey, by personnel from the Naval AirDevelopment Unit, South Weymouth andA i r s h i p A i r b o r n e E a r l y W a r n i n gSquadron 1.

The weather proved to be the roughestpart of the test. It was the worst the areahad experienced in 35 years. The crewsand their airships dealt with snow,freezing rain, icing, sleet, fog, rain, zerotemperatures and high surface winds.During the patrol , al l mi l i tary andcommercial aircraft were grounded dueto severe weather, but the airships keptgoing and continued their patrolswithout mishap.

W i t h t h e s e t e s t s c o m p l e t e dsuccessfully, the drama involving thefinal phase of the tests, a long-distanceflight, took center ring. The Navy was outto do nothing less than break the long-distance record set by the German rigidairship Graf Zeppelin in 1929, when sheflew nonstop from Friedrichshafen,Germany, to Tokyo, Japan, a distance of6,980 miles, without refueling. Therehad not been a transatlantic airship flightin 12 years.

The long-distance flight had its origins

Above, a view of a ZPG-3W cockpit. The N-series airships were the first non-rigid airships tohave controls similar to those of an airplane. Below, a ZS2G-1 airship operating at NASLakehurst. In the background is a ZPG-2W airborne early warning airship.

A close-up view of a ZPG-3W being prepared forundocking. The triangular-shaped mooring masthad a two-foot-wide center shaft and was sevenstories high.

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in the early fifties when the Navy’s LTAadvocates were struggling to prove thecapabilities and suitability of airshipoperations in a modern and fast-movingNavy. The success of the airship in WW IIhad been eclipsed by the new advancesin fixed-wing aircraft. Thus, it wasthought necessary to demonstrate anewthe capabilities of the airship platform toprove it could perform the duties requiredfor ASW and AEW operations. Theserequirements were accentuated by thegrowing need for a reliable airborneplatform which could operate around theclock in all types of weather.

The crew of the Snow Bird (the name ofthe ZPG-2 airship used in the long-distance flight) was a specially selectedgroup of volunteers. Each man had aspecial talent which would contribute tothe success of the operation. The pilot incommand was Commander Jack R. Hunt,supported by two copilots, CommanderRonald W. Hoel and L ieutenantC o m m a n d e r R o b e r t S . B o w s e r .N a v i g a t o r s f o r t h e f l i g h t w e r eLieutenants Stanley W. Dunton andCharles J. Eadie. Lieutenant John R.Fitzpatrick and Mr. Edgar L. Moore ofGoodyear served as flight engineers.Moore was the only civilian to make theflight. The crew chief was CPO Lee N.Steffen who also doubled as radarmanand radioman. Aerology and photographywork was done by Petty Officer FirstClass William S. Dehn, Jr. Petty OfficerFirst Class Thomas L. Cox and PettyOfficer Second Class James R. Burkettwere the flight mechanics, while PettyOfficer First Class Carl W. Meyer was theelectrician. Petty Officer Second ClassFrancis J. Maxymillion worked with ChiefSteffen as radioman and radarman. PettyOfficer Second Class George A. Locklear,served as rigger and doubled with PettyOfficer First Class Dehn as cooks for theflight. Cdr. Hoel was the commandingofficer of the Naval Air Development Unitat South Weymouth and senior officer onboard the flight, but Cdr. Hunt flew asairship commander. Cdr. Hunt and Lt.Cdr. Bowser were the only two LTA pilotson the flight.

Extensive preparations had been madefor the flight. Fuel consumption wascarefully calculated and graphicallyplotted. Every item taken aboard wascarefully weighed to ensure the ZPG-2airship would be within the weight limitsnecessary for correct fuel consumptionand lift rate. Other problems, such asweather reports and communicationlinks, were meticulously worked out.Tension and excitement brought thecrew to a high pitch of enthusiasm as thehour drew near for takeoff. On Monday,March 4, 1957, at 1832 (EST) Snow Birdlifted off from Naval Air Station, SouthWeymouth for her epic-making flight.

Problems with strong crosswinds wereexperienced on takeoff but they wereovercome and Snow Bird was airborne.Cdrs. Hunt and Hoel and Petty OfficerLocklear had to repair Lt. Eadie’s bunk,which was smashed on takeoff becauseof the weight of equipment stored on it.Aside from this mishap, the first fewhours o f f l i gh t we re p roceed ingaccording to plan.

Snow Bird experienced her secondproblem not more than 600 miles at sea.The airship entered a storm area wheresnow was falling, with a fair amount ofturbulence in the air. The previous threephases of the tests had proven theairship’s capability to withstand badweather and the crew was confident ofher ability to survive without mishap. Theproblem resolved itself as Snow Birdmoved out of the storm area.

It was early morning, March 6, and thelog read, “Lights below...freighter. Radarshows no land...good...there are peaks inthe Azores. “Snow Bird was making goodspeed and, as they neared the Azores, themoun ta inous i s l ands cou ld havepresented a problem. Altitude was 1,000feet, well below the peaks.

The transatlantic flyers were assistedby a wind blowing from the southwestwhich was acting as a tail wind for theairship. The critical decision now waswhether to head southward toward the

easterly trade winds which would helpthem on their return flight. The problemlay in the leg south where they would bebucking a head wind which would slowtheir southerly journey and requiregreater consumption of fuel. The crewgrew more anxious as they awaitedweather reports from Fleet WeatherCentral in Washington, D.C.

Reports for the evening of March 6were not favorable. Nevertheless, SnowBird turned south and attempted toeconomize on fuel with slow enginespeeds. Weather reports on the morningo f t he 7 th con t i nued to ca l l f o runfavorable wind conditions on thisheading. A course change was made andSnow Bird headed east, going to single-engine operation to conserve fuel.

Minor problems began to crop up. Anengine sputtered or the air pressurealarm went off, causing brief periods ofanxiety before each si tuat ion wasrectified. The wind, however, continuedto be the major problem. The voyage hadbeen planned to allow for a moderateconsumption of fuel which would keepSnow Bird in the air for 12 days. If shecontinued to experience head windproblems, there would not be enough forthe return flight. The airship commanderbriefed the crew on the possibility oflanding at Port Lyautey, Morocco, to takeon fuel in keeping with contingency

Members of the Snow Bird crew that set the long-range endurance and distance records for anairship in 1957.

The ZPG-2 Snow Bird as it departed NAS South Weymouth, Mass., on its record-breakingflight in March 1957.

plans. A portable mooring mast had beenstowed aboard Super Constellationwhich was to fly ahead of Snow Bird andbe available at designated landing sites ifneeded. Snow Bird continued eastwardand delayed the decision about landing.Nevertheless the Super Connie wasdirected to fly to Port Lyautey and makecontingency preparations in case theairship had to land.

On the the evening of the 7th, lightswere sighted on the southwest tip ofPortugal. Snow Bird headed south at thispoint toward the Canary and Cape VerdeIslands. One leg of the trip had beencompleted. This in itself was a significantachievement, for an airship had notcrossed the Atlantic since-the days ofWW II. Further, the crossings made byZP-14 in 1944 and 1945 were by way ofthe Azores. Snow B i rd ' s nonstoptransatlantic crossing was the first for anonrigid airship.

The winds along the Portuguese coastwere out of the south but not as strong ashad been encountered further out to sea,and Snow Bird was able to make bettertime. By the morning of the 8th, theairship had passed Casablanca, theweather had improved and conditionslooked better for the return trip. Thedecision was made at this time not toland at Port Lyautey. The log read, ”Nowwe’re committed.” It was the beginningof the long leg home. As they neared theCanary Islands late on the evening of the

8th. the log read, “Good tailwind. Crewhappy.”

On the evening of March 9, after fivedays in the air, Snow Bird passed theCape Verde Islands heading for theCaribbean. It was a long 2,500 miles toPuerto Rico.

Habitability aboard Snow Bird wasproving to be palatable. Morale was highand the close quarters did not appear tobother anyone. Life was very similar towhat might be expected aboard a smallsurface vessel crossing the Atlantic.Even the gentle motion of the control carwas similar to the movement of a smallship. The car was 83 feet long and 11 andone-half feet wide, and was divided intotwo leve l s . The upper deck hadcomfortable bunks and a wardroomequipped with a modern galley. Thelower spaces housed the operational partof the car. This was where all the controlsfor flying the airship, as well as theequipment necessary to perform themission assigned, were located.

The dietary needs of the men had beenan important part of the planning for thejourney. Variety, space requirements andpreserva t ion were a l l taken in toconsideration when food was orderedand brought aboard. It was necessary toset up a ration system to ensure anadequate supply for the entire trip. Thiswas accomplished by placing each day’sration in separate bags. It also preventedany one item from being consumed

ahead of schedule. A total of 1,017pounds of food had been loaded aboardSnow Bird for the flight.

The trip had thus far provided a varietyof diversions. Icebergs had been sightedduring the early part of the journey in thenorthern Atlantic. A large number ofbirds, sharks and whales were always onhand. It was especially exhilarating to seeanother aircraft or a surface vessel comeinto view. It made one think of theexcitement which must have beengenerated in the days of sailing vesselswhen another ship was seen on thehorizon after a long period at sea.

The routine of watches and operationald u t i e s d u r i n g t h e v o y a g e w a saccompanied by good-natured banter. Anentry in the log for March 10 indicatedthat Cdr. Hoel and Lt. Fitzpatrick eachowed a round of beer for inadvertentlyringing the air pressure alarm bell. Infact, a sign was made for them for theirwatch. It read “Welcome to the BellRinger’s Club.”

Aircrewmen load food and supplies aboard theSnow Bird in preparation for its flight.

The camaraderie during the journeyextended to a surprise party held for PODehn in honor of his birthday on March12. PO Locklear put his inventive culinaryskills to work and baked a cake in anelectric frying pan. Candles had not beena priority item for the trip but the problemwas solved when filter-tip cigaretteswere substituted. It was a completesurprise to PO Dehn and the party wasenjoyed by all hands.

Tension and excitement began tomount on March 12. This was the eighthday of the voyage and Snow Bird wasclosing in on the record for continuousnon-refueled fl ight, which was 200hours and 12 minutes aloft. Snow Birdofficially eclipsed this record at 0245(EST) on March 13, and broke a secondrecord later that day. The distance recordestablished by the German airship GrafZeppelin in August 1929 fell when SnowBird passed the 6,980-mile mark in hertricontinental journey.

Snow Bird continued her flight, havingestablished two new world records. OnMarch 15, 1957, at 1844, Snow Birdlanded at NAS Key West. The voyage took

264.2 hours and covered a distance of9,448 miles. No airship of any type hadever flown that far or remained aloft thatlong without refueling.

Snow Bird was met by a large crowd.Crew members were personallycongratulated by Admiral William F.Halsey, Jr., on behalf of PresidentDwight D. Eisenhower and the U.S. Navy.Awards were presented and specialcommendations read. It was a greatmoment for the 14 members of SnowBird’s crew and a proud achievement forthe United States.

For his contributions as commanderand pilot of Snow Bird’s record flight, Cdr.Hunt was awarded the HarmonInternational Trophy on November 12,1958. The award was presented to himby President Eisenhower.

XVII. The Demise of LTA and aPossible Revival

Despite such impressive demonstra-tions, there followed a slow reduction inthe airship force. On June 28, 1957, ZPs

1 and 4 were disestablished, and ZX-11was disestablished on December 1 ofthat same year. Still, there was hope thatdecision makers could be convinced ofthe value of the airship to Naval Aviationand that the trend could be reversed.

During this period, airships continuedto undertake unusual projects not in therealm of normal operations. In 1958, aZPG-2 was assigned to assist in an arcticweather research project, which was toevaluate the use of airships in the harsha r c t i c e n v i r o n m e n t . T h e a i r s h i pproceeded across the Arctic Circlewithout incident. Mail and supplies weredropped to scientists at their arctic icestation and a number of scientificexperiments were conducted by theairship’s crew before they returned toSouth Weymouth on August 12, 1958. Inall, it had been a 9,400-mile journey, thelongest arctic flight ever made by a non-rigid airship.

But the stand-down continued. OnNovember 30, 1959, ZP-2, the oldestairship patrol squadron in the Navy, wentout of business. ZW-1 was redesignatedZP-1 on January 3, 1961, and continueda s a n A S W s q u a d r o n . B u t t h ehandwriting was on the wall.

That same month, an N-series airshipflew cross-country from NAS Lakehurstto MCAF El Toro to participate in anoceanographic research project off thecoast of Calif. Her return flight in Marchof that year was the last major long-distance flight of an airship in the U.S.Navy.

On June 21, 1961, the Secretary of theNavy announced plans to terminate theNavy’s LTA program and, by the end ofOctober 1961, ZPs 1 and 3 weredisestablished. They were the lastoperating units of the Navy’s LTA branch.

The last flight of a naval airship onAugust 31, 1962, saw the end of the LTAera in the Navy. During the followingdecade , va r ious ind iv idua ls andorganizations attempted to rekindle theNavy’s interest in LTA. These attemptswere generally not successful althoughsome minor s tudies on LTA wereconducted. During the energy crisis in1973 the Navy, as well as many othergovernment departments, made fueleconomy the number one priority. Withenergy conservation in mind, the Navyestablished an LTA Project Office atN a v a l A i r D e v e l o p m e n t C e n t e r ,Warminster, Pa., on July 29, 1975. Thepurpose of the office was to investigatethe status of LTA technology, in terms ofnew advances and improvements intechnology and the economic feasibilityof LTA applications in various roles.

The LTA Project Office studied thedevelopment of heavy-lift hybrid airshipsand evaluated airships for maritimesurve i l l ance and o ther m iss ions .Through these studies, standard design