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1. INTRODUCTION

WING

Definition:

Wings are airfoils that, when moved rapidly through the air, create lift. They are built in

many shapes and sizes. Wing design can vary to provide certain desirable flight characteristics.

Control at various operating speeds, the amount of lift generated, balance, and stability all

change as the shape of the wing is altered.

The wings of an aircraft can be attached to the fuselage at the top, mid-fuselage, or at the

bottom. They may extend perpendicular to the horizontal plain of the fuselage or can angle up or

down slightly. The wings of an aircraft are designed to lift it into the air. Their particular design

for any given aircraft depends on a number of factors, such as size, weight, use of the aircraft,

desired speed in flight and at landing, and desired rate of climb.

1.1 FIXED WING:

Fixed-wing aircraft, popularly called aero planes, airplanes or just planes may be built

with many wing configurations. This page provides a breakdown of types, allowing a full

description of any aircraft's wing configuration. For example the Spitfire wing may be classified

as a conventional low wing cantilever monoplane with straight elliptical wings of moderate

aspect ratio and slight dihedral. Sometimes the distinction between types is blurred, for example

the wings of many modern combat aircraft may be described either as cropped compound deltas

with (forwards or backwards) swept trailing edge, or as sharply tapered swept wings with large

"Leading Edge Root Extension" (or LERX).

All the configurations described have flown (if only very briefly) on full-size aircraft,

except as noted. Some variants may be duplicated under more than one heading, due to their

complex nature. This is particularly so for variable geometry and combined (closed) wing types.

Fixed-wing aircraft can have different numbers of wings:

Monoplane: one wing plane. Since the 1930s most aero planes have been

monoplanes.

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The wing may be mounted at various positions relative to the fuselage:

Low wing: mounted near or below the bottom of the fuselage.

Mid wing: mounted approximately halfway up the fuselage.

Shoulder wing: mounted on the upper part or "shoulder" of the fuselage, slightly

below the top of the fuselage. A shoulder wing is sometimes considered a subtype

of high wing.

High wing: mounted on the upper fuselage. When contrasted to the shoulder wing,

applies to a wing mounted on a projection (such as the cabin roof) above the top of

the main fuselage.

Parasol wing: raised clear above the top of the fuselage, typically by cabane struts,

pylon(s) or pedestal(s).

Low wing

Mid wing

Shoulder wing

High wing

Parasol wing

Fig 1.1

A fixed-wing aircraft may have more than one wing plane, stacked one above another:

Biplane: two wing planes of similar size, stacked one above the other. The most

common configuration until the 1930s, when the monoplane took over. The Wright

Flyer I was a biplane.

Unequal-span biplane: a biplane in which one wing (usually the lower) is shorter

than the other, as on the Curtiss JN-4 Jenny of the First World War.

Sesquiplane: literally "one-and-a-half planes" is a type of biplane in which the

lower wing is significantly smaller than the upper wing, either in span or chord or

both. The Nieuport 17 of WWI was notably successful.

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Inverted sesquiplane: has a significantly smaller upper wing. The Fiat CR.1 was

in production for many years.

Biplane Unequal-span biplane

Sesquiplane Inverted-Sesquiplane

Fig 1.2

Triplane: three planes stacked one above another. Triplanes such as the Fokker

Dr.I enjoyed a brief period of popularity during the First World War due to their

manoeuvrability, but were soon replaced by improved biplanes.

Quadruplane: four planes stacked one above another. A small number of

the Armstrong Whitworth F.K.10 were built in the First World War but never saw

service.

Multiplane: many planes, sometimes used to mean more than one or more than some

arbitrary number. The term is occasionally applied to arrangements stacked in tandem

as well as vertically. The 1907 Multiplane of Horatio Frederick Phillips flew

successfully with two hundred wing foils, while the nine-wing Caproni Ca.60 flying

boat was airborne briefly before crashing.

Triplane

Quadruplane

Multiplane

Fig 1.3

A staggered design has the upper wing slightly forward of the lower. Long thought

to reduce the interference caused by the low pressure air over the lower wing mixing

with the high pressure air under the upper wing however the improvement is minimal

and its primary benefit is to improve access to the fuselage. It is common on many

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successful biplanes and triplanes. Backwards stagger is also seen in a few examples

such as the Beechcraft Staggerwing.

Unstaggered biplane

Forwards stagger

Backwards stagger

Fig 1.4

A tandem wing design has two wings, one behind the other: see Tailplanes and fore

planes below. Some early types had tandem stacks of multiple planes—see the article

on multiplanes.

1.2 Wing support

To support itself a wing has to be rigid and strong and consequently may be heavy. By adding

external bracing, the weight can be greatly reduced. Originally such bracing was always present,

but it causes a large amount of drag at higher speeds and has not been used for faster designs

since the early 1930s.

The types are:

Cantilevered: self-supporting. All the structure is buried under the aerodynamic skin, giving

a clean appearance with low drag.

Braced: the wings are supported by external structural members. Nearly all multi-plane

designs are braced. Some monoplanes, especially early designs such as the Fokker

Eindecker, are also braced to save weight. Braced wings are of two types:

Strut braced: one or more stiff struts help to support the wing. A strut may act in

compression or tension at different points in the flight regime.

Wire braced: alone (as on the Boeing P-26 Peashooter) or, more usually, in addition to

struts, tension wires also help to support the wing. Unlike a strut, a wire can act only in

tension.

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Cantilever

Strut braced

Wire braced

Fig 1.5

A braced multiplane may have one or more "bays", which are the compartments created

by adding interplane struts; the number of bays refers to one side of the aircraft's wing

panels only. For example, the de Havilland Tiger Moth is a single-bay biplane where

the Bristol F.2 Fighter is a two-bay biplane.

Single-bay biplane

Two-bay biplane

Fig 1.6

Non planar wing or closed wing two wings in different planes are joined structurally at

or near the tips in some way. This may stiffen the structure, and can reduce aerodynamic

losses at the tips. Variants include:

Box wing: upper and lower planes are joined by a vertical fin between their tips. The

first officially witnessed unaided takeoff and flight, Santos-Dumont´s 14-bis, used

this configuration and some Dunne biplanes were of this type as well. Tandem box

wings have also been studied (see Joined wing description below).

Annular box wing: A type of box wing whose vertical fins curve continuously,

blending smoothly into the wing tips. An early example was the Blériot III, which

featured two annular wings in tandem.

Annular (cylindrical): the wing is shaped like a cylinder. The Coléoptère had

concentric wing and fuselage. It took off and landed vertically, but never achieved

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transition to horizontal flight. Examples with the wing mounted on top of the

fuselage have been proposed but never built.

Joined wing: a tandem layout in which the front low wing sweeps back and/or the

rear high wing sweeps forwards such that they join at or near the tips to form a

continuous surface in a hollow diamond or triangle shape. The design has recently

seen a revival of interest where it is referred to as a joined wing. The Ligeti Stratos is

a rare example.

Box wing

Annular box wing

Cylindrical wing

Joined wing

Fig 1.7

Annular wing (planar)

Flat: the wing is shaped like a circular disc with a hole in it. A Lee-Richards type

flew shortly before the First World War.

Rhomboidal wing: an annular wing consisting of four surfaces in a diamond

arrangement. The wing planform looks similar to the joined wing, however here the

two wings are in the same plane. The Edwards Rhomboidal biplane of 1911 failed to

fly. The Small Diameter Bomb, a smart guided bomb, has a rhomboidal wing.

Flat annular

wing

Rhomboidal wing

Fig 1.8

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Wings can also be characterized as:

Igid: stiff enough to maintain the aerofoil profile in varying conditions of airflow. A rigid

wing may have external bracing and/or a fabric covering.

Flexible: usually a thin membrane. Requires external bracing and/or wind pressure to

maintain the aerofoil shape. Common types include Rogallo wings and kites.

Rigid delta wing

Flexible Rogallo "sailwing"

Fig 1.9

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2. WING PLANFORM

The wing planform is the silhouette of the wing when viewed from above or below.

2.1 Aspect ratio

The aspect ratio is the span divided by the mean or average chord. It is a measure of how

long and slender the wing appears when seen from above or below.

Low aspect ratio: short and stubby wing. More efficient structurally and higher

instantaneous roll rate. They tend to be used by fighter aircraft, such as the Lockheed F-

104 Starfighter, and by very high-speed aircraft (e.g. North American X-15).

Moderate aspect ratio: general-purpose wing (e.g. the Lockheed P-80 Shooting Star).

High aspect ratio: long and slender wing. More efficient aerodynamically, having less

induced drag. They tend to be used by high-altitude subsonic aircraft (e.g. the Lockheed

U-2), subsonic airliners (e.g. the Bombardier Dash 8) and by high-performance

sailplanes (e.g. Glaser-Dirks DG-500).

Low aspect ratio

Moderate aspect ratio

High aspect ratio

Fig 2.1

Most Variable geometry configurations vary the aspect ratio in some way, either deliberately

or as a side effect.

2.2 Wing sweep

Wings may be swept back, or occasionally forwards, for a variety of reasons. A small degree

of sweep is sometimes used to adjust the centre of lift when the wing cannot be attached in

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the ideal position for some reason, such as a pilot's visibility from the cockpit. Other uses are

described below.

Straight: extends at right angles to the line of flight. The most structurally-efficient wing,

it is common for low-speed designs, such as the P-80 Shooting Star and sailplanes.

Swept back (aka "swept wing"): The wing sweeps rearwards from the root to the tip. In

early tailless examples, such as the Dunne aircraft, this allowed the outer wing section to

act like a conventional empennage (tail) to provide aerodynamic stability.

At transonic speeds swept wings have lower drag, but can handle badly in or near a stall

and require high stiffness to avoid aero-elasticity at high speeds. Common on high-

subsonic and early supersonic designs e.g. the Hawker Hunter.

Forward swept: the wing angles forward from the root. Benefits are similar to

backwards sweep, also it avoids the stall problems and has reduced tip losses allowing a

smaller wing, but requires even greater stiffness to avoid aero-elastic flutter as on

the Sukhoi Su-47. The HFB-320 Hansa Jet used forward sweep to prevent the wing spar

passing through the cabin. Small shoulder-wing aircraft may use forward sweep to

maintain a correct CoG.

Some types of variable geometry vary the wing sweep during flight:

Swing-wing: also called "variable sweep wing". The left and right hand wings vary their

sweep together, usually backwards. Seen in a few types of military aircraft, such as the

General Dynamics F-111.

Oblique wing: a single full-span wing pivots about its midpoint, so that one side sweeps

back and the other side sweeps forward. Flown on the NASA AD-1 research aircraft.

Straight

Swept

Forward swept

Variable sweep

(swing-wing)

Variable-geometry

oblique wing

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Fig 2.2

2.3 Chord variation along span

The wing chord may be varied along the span of the wing, for both structural and

aerodynamic reasons.

Constant chord: parallel leading & trailing edges. Simplest to make, and common where

low cost is important, e.g. in the Piper J-3 Cub but inefficient as the outer section

generates little lift. Sometimes known as the Hershey Bar wing in North America due to

its similarity in shape to a chocolate bar.

Tapered: wing narrows towards the tip, with straight edges. Structurally and

aerodynamically more efficient than a constant chord wing, and easier to make than the

elliptical type. It is one of the most common wing planforms, as seen on the Grumman

F4F Wildcat.

Trapezoidal: a low aspect ratio tapered wing, where the leading edge sweeps back

and the trailing edge sweeps forwards as on the Lockheed F-22 Raptor.

Inverse tapered: wing is widest near the tip. Structurally inefficient, leading to high

weight. Flown experimentally on the XF-91 Thunderceptor in an attempt to

overcome the stall problems of swept wings.

Compound tapered: taper reverses towards the root. Typically braced to maintain

stiffness. Used on the Westland Lysander army cooperation aircraft to increase

visibility for the pilot.

Constant chord with tapered outer section: common variant seen for example on

many Cessna types and the English Electric Canberra.

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Constant chord Tapered Trapezoidal

Reverse tapered Compound tapered

Constant chord tapered outer

Fig 2.3

Elliptical: leading and trailing edges are curved such that the chord length varies

elliptically with respect to span. Theoretically the most efficient, but difficult to make.

Famously used on the Supermarine Spitfire. (Note that in aerodynamics theory, the term

"elliptical" describes the optimal lift distribution over a wing and not the shape).

Semi-elliptical: only the leading or trailing edge is elliptical with the other being

straight, as with the elliptical trailing edges of the Seversky P-35. Seen in low-

aspect-ratio tailless form on the Arup S-1 and subsequent types.

Elliptical

Semi-elliptical

Fig 2.3.1

Bird wing: a curved shape appearing similar to a bird's outstretched wing. Popular during

the pioneer years, and achieved some success on the Etrich Taube where its planform

was inspired by the zanonia seed.

Bat wing: a form with radial ribs. The 1901 Whitehead No. 21 has been the subject of

claims to the first controlled powered flight.

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Circular: approximately circular planform modified with a horizontal tail. The Vought

XF5U used large propellers near the tips to dissipate its wingtip vortices.

Flying saucer: tailless circular flying wing. The Avrocar demonstrated the inherent

instability of the design, while the Moller M200G used computers to provide

artificial stability in hover mode.

Flat annular wing: the circle has a hole in, forming a closed wing (see above).

Several Lee-Richards types flew shortly before the First World War.

Birdlike

Batlike

Circular

Flying saucer

Flat annular

Fig 2.3.2

Delta: triangular planform with swept leading edge and straight trailing edge. Offers the

advantages of a swept wing, with good structural efficiency and low frontal area.

Disadvantages are the low wing loading and high wetted area needed to obtain

aerodynamic stability. Variants are:

Tailless delta: a classic high-speed design used for example in the widely

built Dassault Mirage III series.

Tailed delta: adds a conventional tailplane, to improve handling. Popular on Soviet

types such as the Mikoyan-Gurevich MiG-21.

Cropped delta: tip is cut off. This helps avoid tip drag at high angles of attack. At

the extreme, merges into the "tapered swept" configuration.

Compound delta or double delta: inner section has a (usually) steeper leading edge

sweep e.g. Saab Draken. This improves the lift at high angles of attack and delays or

prevents stalling. Seen in tailless form on the Tupolev Tu-144 and the Space Shuttle.

The HAL Tejas has an inner section of reduced sweep.

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Ogival delta: a smoothly blended "wineglass" double-curve encompassing the

leading edges and tip of a cropped compound delta. Seen in tailless form on

the Concorde supersonic transports.

Tailless delta

Tailed delta

Cropped delta

Compound delta

Ogival delta

Fig 2.3.3

The angle of sweep may also be varied, or cranked, along the span:

Crescent: wing outer section is swept less sharply than the inner section. Used for

the Handley Page Victor.

Cranked arrow: similar to a compound delta, but with the trailing edge also kinked

inwards. Trialled experimentally on the General Dynamics F-16XL.

M-wing: the inner wing section sweeps forward, and the outer section sweeps backwards.

Periodically studied, but never used on an aircraft.

W-wing: A reversed M-wing. Studied even less than the M-wing and likewise never

used.

Crescent

Cranked arrow

M-wing

W-wing

Fig 2.3.4

2.4 Asymmetrical

On a few aircraft the port and starboard wings are not mirror-images of each other:

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Asymmetrical loading: the Blohm& Voss BV 141 had a nacelle offset to one side to

give the crew a good field of view.

Asymmetrical planform: on several Italian fighters such as the Ansaldo SVA, one wing

was slightly longer than the other to assist in counteracting engine torque.

Oblique wing: one wing sweeps forward and the other back. The NASA AD-1 had a

full-span wing structure with variable sweep.

Asymmetrical Torque counteraction

by asymmetric span

Variable-geometry

oblique wing

Fig 2.4

2.5 Tailplanes and foreplanes

The classic aerofoil section wing is unstable in pitch, and requires some form of horizontal

stabilizing surface. Also it cannot provide any significant pitch control, requiring a separate

control surface (elevator) mounted elsewhere.

Conventional: "tailplane" surface at the rear of the aircraft, forming part of the tail

or empennage.

Canard: "foreplane" surface at the front of the aircraft. Common in the pioneer years, but

from the outbreak of World War I no production model appeared until the Saab Viggen

appeared in 1967.

Tandem: two main wings, one behind the other. Both provide lift; the aft wing provides

pitch stability (as a usual tailplane). An example is the Rutan Quickie. To provide

longitudinal stability, the wings must differ in aerodynamic characteristics: wing loading

and airfoils must be different between the two wings.

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Three surface: both conventional tail and canard auxiliary surfaces. Modern examples

include the Sukhoi Su-33 and Piaggio P.180 Avanti. Pioneer examples included the

Voisin-Farman I and Curtiss No. 1.

Tailless: no separate surface, at front or rear. The lifting and stabilizing surfaces may be

combined in a single plane, as on the Short SB.4 Sherpa whose whole wing tip sections

acted as elevons. Alternatively the aerofoil profile may be modified to provide inherent

stability. Aircraft having a tailplane but no vertical tail fin have also been described as

"tailless".

Conventional

Canard

Tandem

Three surface

Tailless

Fig `2.5

2.6 Dihedral and anhedral

Angling the wings up or down spanwise from root to tip can help to resolve various design

issues, such as stability and control in flight.

Dihedral: the tips are higher than the root as on the Boeing 737, giving a shallow 'V'

shape when seen from the front. Adds lateral stability.

Anhedral: the tips are lower than the root, as on the Ilyushin Il-76; the opposite of

dihedral. Used to reduce stability where some other feature results in too much stability.

Some biplanes have different degrees of dihedral/anhedral on different wings; e.g.

the Sopwith Camel had a flat upper wing and dihedral on the lower wing, while the Hanriot

HD-1had dihedral on the upper wing but none on the lower.

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Dihedral Anhedral

Biplane with dihedral on both wings

Biplane with dihedral on lower wing

Fig 2.6

In a polyhedral wing the dihedral angle varies along the span.

Gull wing: sharp dihedral on the wing root section, little or none on the main section, as

on the PZL P.11 fighter. Sometimes used to improve visibility forwards and upwards and

may be used as the upper wing on a biplane as on the Polikarpov I-153.

Inverted gull: anhedral on the root section, dihedral on the main section. The opposite of

a gull wing. May be used to reduce the length of wing-mounted undercarriage legs or

allow a larger propeller. Two well-known examples of the inverted gull wing are World

War II's American F4U Corsair, and the German Junkers Ju 87 Stuka dive bomber.

Cranked: tip section dihedral differs from the main section. The wingtips may crank

upwards as on the F-4 Phantom II or downwards as on the Northrop XP-56 Black Bullet.

(Note that the term "cranked" varies in usage. Here, it is used to help clarify the

relationship between changes of dihedral nearer the wing tip vs. nearer the wing root.

See also Cranked arrow planform.)

Gull wing Inverted gull wing

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Upward cranked tips

Downward cranked tips

Fig 2.6.1

The channel wing includes a section of the wing forming a partial duct around or

immediately behind a propeller. Flown since 1942 in prototype form only, most notably

on the Custer Channel Wing aircraft.

Channel wing

Fig 2.6.2

2.7 Wings vs. bodies

Some designs have no clear join between wing and fuselage, or body. This may be because

one or other of these is missing, or because they merge into each other:

Flying wing: the aircraft has no distinct fuselage or horizontal tail (although fins and

pods, blisters, etc. may be present) such as on the B-2 stealth bomber.

Bi-directional flying wing: a proposed design in which a low-speed wing and a

high-speed wing are laid across each other in the form of a cross. The aircraft would

take off and land with the low-speed wing facing the airflow, then rotate a quarter-

turn so that the high-speed wing faces the airflow for supersonic flight (see Variable

geometry below).

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Blended body or blended wing-body: a smooth transition occurs between wing and

fuselage, with no hard dividing line. Reduces wetted area and can also reduce

interference between airflow over the wing root and any adjacent body, in both cases

reducing drag. The Lockheed SR-71 spy plane exemplifies this approach.

Lifting body: the aircraft lacks identifiable wings but relies on the fuselage (usually at

high speeds or high angles of attack) to provide aerodynamic lift as on the X-24.

Flying wing

Blended body

Lifting body

Fig 2.7

Some designs may fall into multiple categories depending on interpretation, for example one

design could be seen as a lifting body with a broad fuselage, or as a low-aspect-ratio flying

wing with a deep center chord.

2.8 Variable geometry

A variable geometry aircraft is able to change its physical configuration during flight.

Some types of variable geometry craft transition between fixed wing and rotary wing

configurations. For more about these hybrids, see powered lift.

Variable planform

Variable-sweep wing or Swing-wing. The left and right hand wings vary their sweep

together, usually backwards. The first successful wing sweep in flight was carried out by

the Bell X-5 in the early 1950s. In the Beech Starship, only the canard foreplanes have

variable sweep.

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Oblique wing: a single full-span wing pivot about its midpoint, as used on the NASA

AD-1, so that one side sweeps back and the other side sweeps forward.

Telescoping wing: the outer section of wing telescopes over or within the inner section

of wing, varying span, aspect ratio and wing area, as used on the FS-29 TF glider. The

Makhonine Mak-123 was an early example.

Extending wing or expanding wing: part of the wing retracts into the main aircraft

structure to reduce drag and low-altitude buffet for high-speed flight, and is extended

only for takeoff, low-speed cruise and landing. The GérinVarivol biplane, which flew in

1936, extended the leading and trailing edges to increase wing area.

Bi-directional wing: a proposed design in which a low-speed wing and a high-speed

wing are laid across each other in the form of a cross. The aircraft would take off and

land with the low-speed wing facing the airflow, then rotate a quarter-turn so that the

high-speed wing faces the airflow for supersonic flight.

Variable sweep

(swing-wing)

Variable-geometry

oblique wing

Telescoping wing

Extending wing Bi-directional flying wing

Fig 2.8

Folding wing: part of the wing extends for takeoff and landing, and folds away for high-

speed flight. The outer sections of the XB-70 Valkyrie wing folded down, to increase lift

and reduce drag through generation of 'compression lift' during supersonic flight. (Many

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aircraft have wings that may be folded for storage on the ground or on board ship. These

are not folding wings in the sense used here).

Folding wing

Fig 2.8.1

Variable chord

Variable incidence: the wing plane can tilt upwards or downwards relative to the

fuselage. The wing on the Vought F-8 Crusader was rotated, lifting the leading edge on

takeoff to improve performance. If powered prop-rotors are fitted to the wing to

allow vertical takeoff or STOVL performance, merges into the powered lift category.

Variable camber: the leading and/or trailing edge sections of the whole wing pivot to

increase the effective camber and sometimes also area of the wing. This enhances

manoeuvrability. An early example was flown on the Westland N.16 of 1917.

Variable thickness: the upper wing centre section can be raised to increase wing

thickness and camber for landing and take-off, and reduced for high speed. Charles

Rocheville and others flew some experimental aircraft.

Variable incidence

wing

Variable camber

aerofoil

Variable thickness

aerofoil

Fig 2.8.2

Polymorphism

A polymorphic wing is able to change the number of planes in flight. The Nikitin-

Shevchenko IS "folding fighter" prototypes were able to morph between biplane and

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monoplane configurations after takeoff by folding the lower wing into a cavity in the upper

wing.

The slip wing is a variation on the polymorphic idea, whereby a low-wing monoplane was

fitted with a second detachable "slip" wing above it to assist takeoff, which was then

jettisoned once aloft. The idea was flown on the purpose-built Hillson Bi-mono before being

applied to a single Hawker Hurricane however it was not continued with.

Polymorphic wing

Slip wing

Fig 2.8.3

Minor independent surfaces

Different kinds of strake

Fig 2.8.4

Aircraft may have additional minor aerodynamic surfaces. Some of these are treated as part

of the overall wing configuration:

Winglet: a small vertical fin at the wingtip, usually turned upwards. Reduces the size of

vortices shed by the wingtip, and hence also tip drag.

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Strake: a small surface, typically longer than it is wide and mounted on the fuselage.

Strakes may be located at various positions in order to improve aerodynamic behaviour.

Leading edge root extensions (LERX) are also sometimes referred to as wing strakes.

Chine: long, narrow sideways extension to the fuselage, blending into the main wing. As

well as improving low speed (high angle of attack) handling, provides extra lift at

supersonic speeds for minimal increase in drag. Seen on the Lockheed SR-71 Blackbird.

Moustache: small high-aspect-ratio canard surface having no movable control surface.

Typically is retractable for high speed flight. Deflects air downward onto the wing root,

to delay the stall. Seen on the Dassault Milan and Tupolev Tu-144.

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LITERATURE REVIEW

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3.LITERATURE REVIEW

3.1 A Review Of Morphing Aircraft Silvestro Barbarino,1,* Onur Bilgen,1 Rafic M. Ajaj,1

Michael I. Friswell1 And Daniel J. Inman2[1]

This article presents a review of the state-of- the-art on morphing aircraft and focuses on

structural, shape-changing morphing concepts for both fixed and rotary wings, with particular

reference to active systems. Inflatable solutions have been not considered, and skin issues and

challenges are not discussed in detail.

Although many interesting concepts have been synthesized, few have progressed to wing tunnel

testing, and even fewer have flown. Furthermore, any successful wing morphing system must

overcome the weight penalty due to the additional actuation systems.

The challenge is to design a structure that is capable of withstanding the prescribed loads, but is

also able to change its shape: ideally, there should be no distinction between the structure and the

actuation system. Morphing is a promising enabling technology for the future, next-generation

aircraft. However, manufacturers and end users are still too sceptical of the benefits to adopt

morphing in the near future.

3.2 “Theoretical and Experimental Study of a Forward Swept Wing” Dr. Ibtisam A.

Hassan, Dr. A. S. Darwish Hayder, M. Jaffal[2]

The aerodynamic characteristics of forward swept wing were studied theoretically and

experimentally .In the present work, theoretically a computer program was constructed to predict

the pressure distribution about surface of the wing using three dimensional Low Order Subsonic

Panel method. The aerodynamic coefficients of the wing were calculated from the pressure

distribution which gained from tangential velocities Experimentally ,test were carried out by

designing and manufacturing a wing model with special arrangement for pressure tapping,

suitable for low wind tunnel testing. The entire wing was rotated rotate about an axis in the plane

of symmetry and normal to the chord to produce different sweep and incidence angles for wing,

by using rotating mechanism. Wind tunnel test was carried out at (U∞=33.23m/s) for different

swept angles and angles of attack.

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Comparisons were made between the predicted and experimental results. It is good and gave

reasonable closeness. It was clear from the present investigation that the lift and drag

characteristics for the forward swept wing are less in values compared with the swept back wing,

therefore a forward swept wing.

3.3 “Conceptual Assessment of An Oblique Flying Wing Aircraft Including Control And

Trim Characteristics” Ryan W. Plumley[3]

A method was developed to assist with the understanding of a unique configuration and

investigate some of its stability and control attributes. Oblique wing aircraft concepts are a

design option that is well understood, but has yet to be used in a production aircraft. Risk

involved in choosing such a design can be averted through additional knowledge early in the

concept evaluation phase.

Analysis tools commonly used in early conceptual level analysis were evaluated for applicability

to a non-standard aircraft design such as an oblique flying wing. Many tools used in early

analyses make assumptions that are incompatible with the slewed wing configuration of the

vehicle.

Using a simplified set of tools, an investigation of a unique configuration was done as well as

showing that the aircraft could be trimmed at given conditions. Wave drag was investigated to

determine benefits for an oblique flying wing. This form of drag was reduced by the distribution

of volume afforded by the slewing of the aircraft’s wing. Once a reasonable concept was

developed, aerodynamic conditions were investigated for static stability of the aircraft.

Longitudinal and lateral trim were established simultaneously due to its asymmetric nature.

3.4 “Aerodynamic Performance and Shedding Characteristics on A Swept-Back Wing”

Shun-Chang Yen [4]

A NACA 0012 finite swept-back wing with a sweep-back angle of 15° was utilized to investigate

the effects of angle of attack (α) and the chord Reynolds number (Rec) on the vortex shedding

and aerodynamic coefficients. A hot-wire anemometer was applied to measure the vortex-

26

shedding frequency. The projected Strouhal number (Std) at various angles of attack was

determined and discussed.

The relationship between Std and α is regressed as: Std = -0.0008 α + 0.209, for 22° < α < 90°.

Four characteristic surface-flow patterns: separation bubble, leading-edge bubble, bubble burst,

and turbulent separation were classified by changing α and Re.

The behavior of surface-flow structures significantly affects the lift, drag, and moment

coefficients. The lift coefficient (CL) increases with α in the separation bubble and leading-edge

bubble regimes. The maximum increase rate of CL with respect to α (d(CL)/dα) is 1.52 π/rad.

Occurring in the leading edge bubble regime. However, the maximum increase rate of drag

coefficient (CD) with respect to α (d(CD)/dα) is 0.49 π/rad. Occurring in the bubble-burst

regime. The steep-drop of moment coefficient at stall in the unswept-wings is not observed in the

swept-back wings.

3.5 “Design, fabrication, and analysis of a 3DOF, 3cm flapping-wing MAV” R.J. Wood [5]

Significant advances in meso-scale prototyping are enabling rigid, articulated, and actuated

micro robotic structures. Here, an elegant manufacturing paradigm is employed for the creation

of a biologically inspired flapping-wing micro air vehicle with similar dimensions to Dipteran

insects. A novel wing transmission system is presented which contains one actuated and two

passive degrees of freedom. The design and fabrication are detailed and the performance of the

resulting structure is elucidated highlighting two key metrics: the wing trajectory and the thrust

generated.

3.6 “Design And Fabrication Of Delta Wing Shape Mav” Aghil Yousefi Koma, Sepideh

Afshar1, Hesam Maleki, Donya Mohammadshahi, Hossein Shahi [6]

Design and fabrication of a body less MAV is presented in this paper. Body less MAVs take

advantage of more lift and less drag. A triangular wing is chosen to this end and two models are

fabricated to investigate winglet effect in aerodynamic properties, especially roll and yaw

stability. The results show that this wing form can provide the requirements of a conventional

27

model. Besides, the model proves good maneuverability characteristics. On the other hand, lake

of winglets lead to a decrease in stability characters in designed MAV.

3.7 “Design and test of a UAV blended wing body Configuration” Kai lehmkuehler , kc

wong and dries verstraete [7]

This paper presents the design and test of a UAV blended wing body configuration. It is the

result of a global student design project between the University of Sydney, the University of

Colorado and the University of Stuttgart. Firstly, the design methodology and constraints are

introduced.

Then the wind tunnel test setup is described and the data presented. Finally, an engineering

method to predict the propulsion effects on this unusual airframe is described. Comparison

between the wind tunnel data and panel code predictions shows good agreement, also reinforced

by successful flight tests.

Propulsion effects on a low stability airframe can be serious and need to be considered during the

design to avoid possible instabilities. The method presented allows for a quick estimate without

tedious computations or tests.

3.8 “Design of a turbulent wing for small aircraft Using multidisciplinary optimisation”

W. Stalewski, j. Żołtak[8]

Design process of a turbulent wing for small aircraft, using multidisciplinary and multi-objective

optimisation, based on a genetic algorithm was presented. A generic parametric model of small

aircraft wing geometry was developed. In the model, a wide class of wing geometries, with and

without high lift devices, was described by a relatively small number of parameters. The

optimisation method used the objectives and constraints typical for multidisciplinary wing

design, and was applied to the design and optimisation of turbulent wing dedicated for small,

two-propeller aircraft. The research was conducted within European Project CESAR. The results

of the research have been discussed.

28

3.9 “Velocity Distribution on Thin Tapered Wings with Fore-and-aft Symmetry and

Spanwise Constant Thickness Ratio at Zero lncidence” S. N~.UMARK, Techn.Sc.D.,

A.F.R.Ae.S., and J. COLLINGBOURNE, B.Sc.[9]

This report is a continuation of three earlier ones by the present authors 1' 2, a (1947-9) and

contains a theoretical investigation of subsonic flow past thin tapered unswept wings (of full or

cropped-rhombus plan form), at zero incidence. Only the case of spanwise constant thickness

ratio is considered in this first attempt although alternative cases also merit attention. The first

order method of linear perturbation based on continuous systems of sources and sinks is shown

to be still applicable to tapered wings, although mathematical difficulties are greatly increased.

These have been overcome, at least in the simple case of the biconvex parabolic profile, so as to

give general solutions and computable formulae for the velocity distribution over the entire wing

area. Complete detailed solutions for the mid-chord line have been worked out numerically and

two examples of complete numerical solutions, with corresponding isobar patterns, for the entire

wing area are presented. These results are sufficient to illustrate the effect of uniform taper on

the velocity field of unswept wings, and lead to a number of general conclusions. The most

important of these is that, although taper brings about noticeable decrease of super velocities at

the centre, higher values are encountered further outboard so that, for cropped plan forms, two

symmetrically placed maximum suction areas arise inside the two half-wings. These are relevant

for determining critical Mach numbers, and the effect of taper may be, according to choice of

geometrical parameters, either beneficial or detrimental as to the values of Motet, but practically

never very considerable.

The method will still be applicable to the more general, and more important, case of tapered

swept-back wings, especially for delta wings, and a general solution for the velocity distribution

in the central sections of such wings is given and shown to be consistent with the earlier solution

for untapered swept wings. However, for applying the method successfully (up to detailed

numerical investigation) to the more general case, automatic high-speed integrating machinery

seems indispensable--to replace classical methods of transforming integrals and manual

computing, as used in the past and in the present report.

29

3.10 “Experimental Investigation of Bistable Winglets to Enhance Wing Lift Takeoff

Capability” A. Gatto, F. Mattioni and M. I. Friswell [10]

An experimental investigation into the use of a bistable winglet to enhance the lift characteristics

of a wing transitioning from lower to higher subsonic flow speeds is presented in this paper. The

concept centres on the use of a specifically designed composite winglet, manufactured with an

asymmetric layup, which, when increasingly loaded, snaps between two stable states. Initially,

during low-speed operation, the winglet is fixed in one stable state that is specifically designed to

be cambered, thus enhancing the lift capability of the wing. At higher dynamic pressures, the

winglet snaps to a configuration more intuitive and conventional to current winglet design.

Results presented in this paper show the concept to be viable at enhancing the lift produced by a

swept wing as aerodynamic loading increases before snap-through. During snap-through,

however, the absence of any method of controlling the snap-through process generated

significant dynamic loading that was transmitted, unhindered, throughout the entire test rig.

3.11. “A review of bird-inspired flapping wing miniature air vehicle designs”. J.W. Gerdes,

S.K. Gupta, and S. Wilkerson [11]

Physical and aerodynamic characteristics of the bird in flight offer benefits over typical propeller

or rotor driven miniature air vehicle (MAV) locomotion designs in certain applications. A

number of research groups and companies have developed flapping wing vehicles that attempt to

harness these benefits. The purpose of this paper is to report different types of flapping wing

miniature air vehicle designs and compare their salient characteristics. This paper is focused on

mechanical design aspects of mechanisms and wings. The discussion presented will be limited to

miniature-sized flapping wing air vehicles, defined as 10 to 100 grams total weight. The

discussion will be focused primarily on designs which have performed at least one successful test

flight.

This paper provides representative designs in each category, rather than providing a

comprehensive listing of all existing designs. This paper will familiarize a newcomer to the field

with existing designs and their distinguishing features. By studying existing designs, future

designers will be able to adopt features from other successful designs. This paper also

30

summarizes the design challenges associated with the further advancement of the field and

deploying flapping wing vehicles in practice.

3.12 “Wing morphing design utilizing macro fiber composite smart materials” Lauren

butt, steve day, joseph weaver, craig sossi1 and artur wolek, Onur bilgen, Dr. William

mason, Dr. Daniel inman [12]

Demonstrate the abilities of morphing materials technology by modifying a current remote

controlled aircraft model using an electric propulsion system and designing and fabricating

control surfaces that use Smart Materials micro-fiber-composites (MFCs). The design must be

marketable in the R/C community.

The requirements for this project as described above contain basic guidelines for this Senior

Design project. First and foremost, it shows a way to replace tradition servo controlled surfaces

with MFC actuated surfaces in an effective manner. Not only will the control surfaces need to

respond as well as, if not better than, the classic servo-motor system, but it will also need to be a

fairly simple, potentially cost effective design that can easily be reproduced. The overall goal of

this project is to showcase the capabilities of MFCs on an aircraft that could be reproduced on a

large scale in today’s R/C market.

3.13 “Interdisciplinary Wing Design – Structural Aspects” Christian Anhalt, Hans Peter

Monner, Elmar Breitbach [13]

The paper describes a multidisciplinary approach to design a wing with almost optimal

aerodynamic efficiency during the entire cruise flight. Therefore a tight collaboration between

structural mechanics and aerodynamics is necessary. Aerodynamic aspects are described here to

illustrate the interdisciplinary nature of the design process, but they are not explained very

deeply. The paper focuses on structural aspects, e.g. description of the tasks of the wings

structural members, their placement within the wing and the modelling of the actual wing

structure.

31

3.14 “A High-Altitude Test of Inflatable Wings for Low-Density Flight Applications”

Suzanne Weaver Smith and Jamey D. Jacob and Robert J. Jones, Stephen E. Scarborough

and David P. Cadogan [14]

Recent projects involving unfolding rigid-wing aircraft have demonstrated high-altitude, low-

density flight capabilities, moving the concept of an unmanned aircraft exploring Mars or Venus

nearer to reality. Motivated by the requirement for a minimal packed-volume to weight ratio, an

alternate approach for the wing design is an inflatable wing. Two previous balloon-launched

high-altitude experiments have successfully demonstrated the feasibility of deploying and curing

inflatable/rigidizable wings. Rugged inflatable wings constructed of materials used for the Mars

Lander airbags with maintained internal pressurization are also a viable alternative for low-

density flight applications. Low-altitude flight tests have demonstrated high reliability, along

with their unique ability for wing shaping to expand flight capabilities.

This paper presents the development and results of a successful high altitude test to demonstrate

the feasibility of rugged inflatable wings for planetary exploration. Flexible solar cells were

mounted on the wing surface to illustrate the potential for multifunctional inflatable structures

with power generation capabilities as well. The balloon-launched experiment concept is

described, along with details of test article design, fabrication and ground testing. The flight test

was conducted on April 30, 2005.

The wings were deployed at approximately 96,000 ft, reaching a maximum altitude of 97,987 ft.

The test article descended under parachute to recovery. Flight results, including onboard images,

temperatures, pressures and solar cell power are included.

3.15 “Multidisciplinary Wing Optimisation” E. Kesseler, M. Laban and W.J. Vankan [15]

In wing design various disciplines are involved. Presently wing design involves a top-level

design, which allocates design targets to each discipline. These disciplines perform their designs,

using discipline specific methods and tools.

The objective of the described multidisciplinary design optimisation is to base the early wing

design on a harmonised set of models and tools. NLR participates in the large European Union

sponsored VIVACE (Value Improvement through a Virtual Aeronautical Collaborative

32

Enterprise) project, which aims to reduce costs and time-to-market for aircraft and engine design.

This paper focuses on the early design of wings.

An automated framework has been realised which couples a number of disciplines tools into an

integrated multidisciplinary design analysis system. The realised framework prototype includes

geometry generation, engine sizing, based on a rubberised engine, weight bookkeeping, Finite

Element Method based structural optimisation (for a JAR/FAR 25 specified load case), high-

fidelity CFD based aerodynamic analysis, mission analysis. A first version of this

multidisciplinary design analysis framework has been realised.

33

PRE-PROCESSING AND CONCEPT FORMULATION

34

4 PRE-PROCESSING AND CONCEPT FORMULATION

4.1 UNDERSTANDING WING CONFIGURATION:

Wing is the main component that enables flight. Wing produces aerodynamic forces which keep

the aircraft airborne. The wing location plays a vital role which affects centre of gravity

placement and other key features’ design.

Wing dominates the stability and performance characteristics of the aircraft.

The location and orientation of a wing determines what type of performance can be achieved,

along with the degrees of freedom that can be implemented on the wing.

Here a new concept is introduced to place and orient the wing as desired by the pilot.

This concept will help and enable different regimes of flight, incorporation of various advantages

found and employed in different wing configurations.

By understanding the wing stability and performances, the wings are pivoted at a certain scale on

the fuselage and can be rotated to five individual motions with the fixed pivot.

The motion will be programmed to the remote control; an attempt of the model can be made to

fly at different wing configurations.

4.2 FUTURE PHASE II WORKS

A scale model is fabricated with the complex mechanism of pivot.

It will be tested in subsonic wind tunnel to find out the aerodynamic forces .

It is further modeled in design software and analysed for the performance of lift in a

suitable analyzing software at different wing configurations and data are compared and

results established.

35

REFERENCES

1. “A Review Of Morphing Aircraft” Silvestro Barbarino, Onur Bilgen, Rafic M. Ajaj, Michael

I. Friswell And Daniel J. Inman college Of Engineering, Swansea University, Singleton

Park, Swansea Sa2 8pp, Uk center For Intelligent Material Systems And Structures, Virginia

Tech, Blacksburg, Va 24061, Usa

2. “Theoretical and Experimental Study of a Forward Swept Wing” Dr. Ibtisam A. Hassan Dr.

A. S. Darwish Hayder M. Jaffal The University of Technology, The University of

Mustansiriyah, Anbar Journal for Engineering Sciences, AJES-2010, Vol.3, No.2

3. “Conceptual Assessment Of An Oblique Flying Wing Aircraft Including Control And Trim

Characteristics” Ryan W. Plumley, Virginia Polytechnic Institute And State University.

4. “Aerodynamic performance and Shedding characteristics on a Swept-back wing” Shun-

chang yen, Journal of marine science and technology, vol. 19, no. 2, pp. 162-167 (2011)

5. “Design, fabrication, and analysis of a 3DOF, 3cm flapping-wing MAV” R.J. Wood School

of Engineering & Applied Sciences Harvard University Cambridge, MA 02138

6. “Design and fabrication of delta wing shape MAV” Aghil yousefi koma, sepideh afshar1,

hesam maleki, donya Mohammadshahi, hossein shahi, Advanced dynamic and control

system laboratory (adcsl), Department of mechanical engineering, university of Tehran,

Tehran, Iran

7. “Design and test of a uav blended wing body Configuration” Kai lehmkuehler_ , kc wong_

and dries verstraete, school of aerospace, mechanical and mechatronic engineering, the

university of sydney, Australia

8. “Design of a turbulent wing for small aircraft Using multidisciplinary optimisation” W.

Stalewski, j. Żołtak Instutut lotnictwa (institute of aviation) Aleja krakowska 110/114 02-

256 warszawa, Poland.

36

9. Velocity Distribution on Thin Tapered Wings with Fore-and-aft Symmetry and Spanwise

Constant Thickness Ratio at Zero Incidence “ NgUMARK, Techn.Sc.D., A.F.R.Ae.S., and J.

COLT~NGBOt~RN~, B.Sc. AERONAUTICAL RESEARCH COUNCIL REPORTS AND

MEMORANDA, 1954

10. “Experimental Investigation of Bistable Winglets to Enhance Wing Lift Takeoff Capability”

A. Gatto Brunel University, Uxbridge, Middlesex, England, UB8 3PH, United Kingdom and

F. Mattioni and M. I. Friswell University of Bristol, Bristol, England, BS8 1TR, United

Kingdom. JOURNAL OF AIRCRAFT, Vol. 46, No. 2, March–April 2009

11. “A review of bird-inspired flapping wing miniature air vehicle designs”. J.W. Gerdes, S.K.

Gupta, and S.Wilkerson. Journal of Mechanism and Robotics, 4(2), 021003.1-021003.11,

2012.

12. “Wing morphing design utilizing macro fiber composite Smart materials” Lauren butt, steve

day, joseph weaver, craig sossi and artur wolek,, Onur bilgen, Dr. William mason, dr. Daniel

inman Virginia tech, blacksburg, va, 24061, The society of allied weight engineers, inc,

Virginia beach, virginia, may 23-26, 2010

13. “Interdisciplinary Wing Design – Structural Aspects” Christian Anhalt, Hans Peter Monner,

Elmar Breitbach German Aerospace Center (DLR), Institute of Structural Mechanics

Copyright © 2003 SAE International.

14. “A High-Altitude Test of Inflatable Wings for Low-Density Flight Applications” Suzanne

Weaver Smith* and Jamey D. Jacob† and University of Kentucky, Lexington, KY 40506 and

Robert J. Jones,‡ Stephen E. Scarborough§ and David P. Cadogan ** ILC Dover, Inc.,

Frederica, DE 19946

15. “Multidisciplinary Wing Optimisation” E. Kesseler, M. Laban and W.J. Vankan, September

2005