Wing configuration

This article is about aircraft wings. For bird wings, see Wing configuration (birds).
The Spitfire wing may be classified as: "a conventional low wing cantilever monoplane with unswept elliptical wings of moderate aspect ratio and slight dihedral".

Fixed-wing aircraft, popularly called aeroplanes, 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 Supermarine 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 extensions (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.

Note on terminology: Most fixed-wing aircraft have left hand and right hand wings in a symmetrical arrangement. Strictly, such a pair of wings is called a wing plane or just plane. However, in certain situations it is common to refer to a plane as a wing, as in "a biplane has two wings", or to refer to the whole thing as a wing, as in "a biplane wing has two planes". Where the meaning is clear, this article follows common usage, only being more precise where needed to avoid real ambiguity or incorrectness.

Number and position of main-planes

Fixed-wing aircraft can have different numbers of wings:

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Low wing
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Mid wing
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Shoulder wing
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High wing
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Parasol wing

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

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Biplane
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Unequal-span biplane
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Sesquiplane
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Inverted sesquiplane
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Triplane
" "
Quadruplane
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Multiplane

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 successful biplanes and triplanes. Backwards stagger is also seen in a few examples such as the Beechcraft Staggerwing.

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Unstaggered biplane
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Forwards stagger
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Backwards stagger

A tandem wing design has two wings, one behind the other: see Tailplanes and foreplanes below. Some early types had tandem stacks of multiple planes—see the article on multiplanes.

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:

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Cantilever
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Strut braced
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Wire braced
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.[3]
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Single-bay biplane
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Two-bay biplane
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Box wing
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Annular box wing
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Cylindrical wing
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Joined wing
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Flat annular wing
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Rhomboidal wing

Wings can also be characterised as:

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Rigid delta wing
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Flexible Rogallo wing

Wing planform

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

See also Variable geometry types which vary the wing planform during flight.

Aspect ratio

Main article: Aspect ratio (wing)

The aspect ratio is the span divided by the mean or average chord.[9] It is a measure of how long and slender the wing appears when seen from above or below.

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Low aspect ratio
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Moderate aspect ratio
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High aspect ratio

Most Variable geometry configurations vary the aspect ratio in some way, either deliberately or as a side effect.

Chord variation along span

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

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Constant chord
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Tapered (Trapezoidal)
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Reverse tapered
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Compound tapered
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Constant chord,
tapered outer
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Elliptical
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Semi-elliptical
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Birdlike
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Batlike
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Circular
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Flying saucer
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Flat annular
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Tailless delta
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Tailed delta
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Cropped delta
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Compound delta
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Ogival delta

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

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

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Straight
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Swept
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Forward swept
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Variable sweep
(swing-wing)
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Variable-geometry
oblique wing

Sweep variation along span

The angle of a swept wing may also be varied, or cranked, along the span:

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Crescent
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Cranked arrow
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M-wing
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W-wing

Asymmetrical

On a few asymmetrical aircraft the left and right wings are not mirror-images of each other:

" " " " " "
Asymmetrical Torque counteraction
by asymmetric span
Variable-geometry
oblique wing

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.

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Conventional
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Canard
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Tandem
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Three surface
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Tailless

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.

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

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Dihedral
 
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Anhedral
 
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Biplane with dihedral
on both wings
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Biplane with dihedral
on lower wing

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

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Gull wing
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Inverted gull wing
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Upward cranked tips
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Downward cranked tips
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Channel wing

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:

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Flying wing
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Blended body
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Lifting body

Some designs may fall into multiple categories depending on interpretation, for example the same design could be seen either as a lifting body with a broad fuselage, or as a low-aspect-ratio flying wing with a deep center chord.

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

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Variable sweep
(swing-wing)
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Variable-geometry
oblique wing
 
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Telescoping wing
 
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Extending wing
 
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Folding wing

Variable chord

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Variable incidence
wing
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Variable camber
aerofoil
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Variable thickness
aerofoil

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 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.

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Polymorphic wing
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Slip wing

Minor independent surfaces

Different kinds of strake

Aircraft may have additional minor aerodynamic surfaces. Some of these are treated as part of the overall wing configuration:

Additional minor features

Additional minor features may be applied to an existing aerodynamic surface such as the main wing:

High lift

High-lift devices

High-lift devices maintain lift at low speeds and delay the stall to allow slower takeoff and landing speeds:

Spanwise flow control

Spanwise flow control device

On a swept wing, air tends to flow sideways as well as backwards and reducing this can improve the efficiency of the wing:

Vortex creation

Vortex devices

Vortex devices maintain airflow at low speeds and delay the stall, by creating a vortex which re-energises the boundary layer close to the wing.

Drag reduction

Drag-reduction devices

Notes

  1. Taylor, J. (Ed.), Jayne's all the world's aircraft 1980-81, Jane's (1980)
  2. Green, W.; Warplanes of the second world war, Vol. 5, Flying boats, Macdonald (1962), p.131
  3. Taylor, 1990. p. 76
  4. Kroo, I. (2005), "Nonplanar Wing Concepts For Increased Aircraft Efficiency", VKI lecture series on Innovative Configurations and Advanced Concepts for Future Civil Aircraft June 6–10, 2005
  5. "Nonplanar Wings: Closed Systems". Aero.stanford.edu. Retrieved 2012-03-31.
  6. Airliners.net, Lee Richards Annular, 2012, retrieved 31 March 2012
  7. Ligeti Stratos joined wing aircraft
  8. Angelucco, E. and Matrciardi, P.; World Aircraft Origins-World War 1, Sampson Low, 1977
  9. Kermode, A.C., Mechanics of Flight, Chapter 3 (p.103, eighth edition)
  10. Garrison, Peter (2003-01-01). "Rectangular Wings | Flying Magazine". Flyingmag.com. Retrieved 2012-03-31.
  11. 3-view of the Piper J-3 Cub
  12. Tom Benson; Wing Area, NASA
  13. Ilan Kroo ; AA241 Aircraft Design: Synthesis and Analysis Wing Geometry Definitions, Stanford University.
  14. G. Dimitriadis; Aircraft Design Lecture 2: Aerodynamics, Université de Liège.
  15. "Alexander de Seversky". centennialofflight.net. Retrieved 2012-03-31.
  16. Potts, J.R.; Disc-wing aerodynamics, University of Manchester, 2005.
  17. letter from Hall-Warren, N.; Flight International, 1962, p 716.
  18. "swept wing | avro vulcan | 1953 | 0030 | Flight Archive". Flightglobal.com. 1952-12-05. Retrieved 2012-05-29.
  19. 1 2 Diederich and Foss; Static Aeroelastic Phenomena of M-, W- and Λ- wings, NACA 1953.
  20. "Aerodynamics at Teddington", Flight: 764, 5 June 1959
  21. 1 2 Katz, Marley, Pepper, NACA RM L50G31 (PDF), NACA
  22. P180 Avanti-Specification and Description. See page 55, Appendix A: "Notes about the 3-Lifting-Surface design".
  23. Ernst-Heinrich Hirschel; Horst Prem; Gero Madelung. Aeronautical research in Germany: from Lilienthal until today. Retrieved 2012-03-31.
  24. Benoliel, Alexander M., Aerodynamic Pitch-up of Cranked Arrow Wings: Estimation, Trim, and Configuration Design, Virginia Polytechnic Institute & State University, May 1994, retrieved 31 March 2012
  25. "Boeing Sonic Cruiser ousts 747X". Flightglobal.com. 2001-04-03. Retrieved 2012-03-31.
  26. "WHAT IS IT? Aircraft Characteristics That Aid the Spotter Classified : A Simple Guide for Basic Features in Design the Beginner", Flight: 562, 4 June 1942
  27. "fs 29 - "TF"". Uni-stuttgart.de. 2012-02-05. Retrieved 2012-03-31.
  28. "Telescoping Wings On Plane Add To Its Speed", November 1931, Popular Mechanics
  29. "Plane With Expanding Wing, Flies In Tests" Popular Science, November 1932, article center of page 31
  30. Lukins, A.H.; The book of Westland aircraft, Aircraft (Technical) Publications Ltd, (1943 or 1944).
  31. "Adjustable Airplane's Wings Are Changed In Flight", January 1931, Popular Mechanics left-bottom of page 55
  32. Flight, August 15 1929
  33. Boyne, W.J.; The best of Wings magazine, Brassey's (2001)
  34. 1 2 Wing vortex devices

References

See also

There is a Wikipedia Book on Aircraft wing configurations

External links

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