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The wing configuration of a
fixed-wing aircraft A fixed-wing aircraft is a heavier-than-air flying machine, such as an airplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are dist ...
(including both gliders and powered
aeroplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spec ...
s) is its arrangement of lifting and related surfaces. Aircraft designs are often classified by their
wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...
configuration. For example, the
Supermarine Spitfire The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Gri ...
is a conventional low wing cantilever monoplane of straight elliptical planform with moderate aspect ratio and slight dihedral. Many variations have been tried. Sometimes the distinction between them 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). Some are therefore duplicated here under more than one heading. This is particularly so for variable geometry and combined (closed) wing types. Most of the configurations described here have flown (if only very briefly) on full-size aircraft. A few theoretical designs are also notable. ''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 alternatively 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: *
Monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...
: one wing plane. Since the 1930s most aeroplanes have been monoplanes. The wing may be mounted at various positions relative to the
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
: **
Low wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
: 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 A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
: raised clear above the top of the fuselage, typically by
cabane strut In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act i ...
s, pylon(s) or pedestal(s). A fixed-wing aircraft may have more than one wing plane, stacked one above another: *
Biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...
: two wing planes of similar size, stacked one above the other. The biplane is inherently lighter and stronger than a monoplane and was the most common configuration until the 1930s. The very first
Wright Flyer I The ''Wright Flyer'' (also known as the ''Kitty Hawk'', ''Flyer'' I or the 1903 ''Flyer'') made the first sustained flight by a manned heavier-than-air powered and controlled aircraft—an airplane—on December 17, 1903. Invented and flown b ...
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 The Curtiss JN "Jenny" was a series of biplanes built by the Curtiss Aeroplane Company of Hammondsport, New York, later the Curtiss Aeroplane and Motor Company. Although the Curtiss JN series was originally produced as a training aircraft for th ...
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 The Nieuport 17 C.1 (or Nieuport XVII C.1 in contemporary sources) was a French sesquiplane fighter designed and manufactured by the Nieuport company during World War I. An improvement over the Nieuport 11, it was a little larger than earlier ...
of World War I was notably successful. ** Inverted sesquiplane: has a significantly smaller upper wing. The
Fiat CR.1 The Fiat CR.1 was an Italian biplane fighter aircraft of the 1920s. Of wood-and-fabric construction, it was designed by Celestino Rosatelli, from whom it gained the 'CR' designation. Its most distinctive feature was that the lower wings were lon ...
was in production for many years. **
Busemann biplane The Busemann biplane is a theoretical aircraft configuration invented by Adolf Busemann, which avoids the formation of N-type shock waves and thus does not create a sonic boom or the associated wave drag. However in its original form it does not ...
: a theoretical supersonic wing configuration, in which shock waves between the wing planes interfere to reduce their energy and wave drag. *
Triplane A triplane is a fixed-wing aircraft equipped with three vertically stacked wing planes. Tailplanes and canard foreplanes are not normally included in this count, although they occasionally are. Design principles The triplane arrangement ma ...
: three planes stacked one above another. Triplanes such as the
Fokker Dr.I The Fokker Dr.I (''Dreidecker'', "triplane" in German), often known simply as the Fokker Triplane, was a World War I fighter aircraft built by Fokker-Flugzeugwerke. The Dr.I saw widespread service in the spring of 1918. It became famous as th ...
enjoyed a brief period of popularity during the First World War due to their manoeuvrability, but were soon replaced by improved biplanes. *
Quadruplane In aviation, a multiplane is a fixed-wing aircraft-configuration featuring multiple wing planes. The wing planes may be stacked one above another, or one behind another, or both in combination. Types having a small number of planes have specific nam ...
: four planes stacked one above another. A small number of the
Armstrong Whitworth F.K.10 The Armstrong Whitworth F.K.10 was a British two-seat quadruplane (''i.e.'', four wing) fighter aircraft built by Armstrong Whitworth during the First World War. While it was ordered in small numbers for the Royal Flying Corps and Royal Nava ...
were built in the First World War but never saw service. *
Multiplane The multiplane camera is a motion-picture camera that was used in the traditional animation process that moves a number of pieces of artwork past the camera at various speeds and at various distances from one another. This creates a sense of par ...
: 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 Horatio Frederick Phillips (1845 – 1924) was an English aviation pioneer, born in Streatham, Surrey. He was famous for building multiplane flying machines with many more sets of lifting surfaces than are normal on modern aircraft. However h ...
flew successfully with two hundred wing foils. See also the tandem wing, below. 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 The Beechcraft Model 17 Staggerwing is an American biplane with an atypical negative wing stagger (the lower wing is farther forward than the upper wing). It first flew in 1932. Development At the height of the Great Depression, aircraft ...
. * A
tandem wing QAC Quickie Q2 A tandem wing is a wing configuration in which a flying craft or animal has two or more sets of wings set one behind another. All the wings contribute to lift. The tandem wing is distinct from the biplane in which the wings are ...
design has two wings, one behind the other: see Tailplanes and foreplanes below. Some early types had tandem stacks of multiple planes, such as the nine-wing
Caproni Ca.60 The Caproni Ca.60 Transaereo, often referred to as the Noviplano (nine-wing) or Capronissimo, was the prototype of a large nine-wing flying boat intended to become a 100-passenger transatlantic airliner. It featured eight engines and three sets ...
flying boat with three triplane stacks in tandem. * A
cruciform wing A cruciform wing is a set of four individual wings arranged in the shape of a cross. The cross may take either of two forms; the wings may be equally spaced around the cross-section of the fuselage, lying in two planes at right angles, as on a typ ...
is a set of four individual wings arranged in the shape of a
cross A cross is a geometrical figure consisting of two intersecting lines or bars, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a s ...
. The cross may take either of two forms: ** Wings equally spaced around the cross-section of the fuselage, lying in two planes at right angles, as on a typical
missile In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket ...
. ** Wings lying together in a single horizontal plane about a vertical axis, as in the cruciform rotor wing or X-wing.


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 A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cant ...
: 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 The Fokker ''Eindecker'' fighters were a series of German World War I monoplane single-seat fighter aircraft designed by Dutch engineer Anthony Fokker.Boyne 1988 Developed in April 1915, the first ''Eindecker'' ("Monoplane") was the first purpose ...
, are also braced to save weight. Braced wings are of two types: ** Strut braced: one or more stiff struts help to support the wing, as on the Fokker D.VII. 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 The Boeing P-26 "Peashooter" was the first American production all-metal fighter aircraft and the first pursuit monoplane to enter squadron service with the United States Army Air Corps. Designed and built by Boeing, the prototype first flew in ...
) 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. :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 The de Havilland DH.82 Tiger Moth is a 1930s British biplane designed by Geoffrey de Havilland and built by the de Havilland Aircraft Company. It was operated by the Royal Air Force (RAF) and other operators as a primary trainer aircraf ...
is a single-bay biplane where the Bristol F.2 Fighter is a two-bay biplane. *
Closed wing A closed wing is a wing that effectively has two main planes which merge at their ends so that there are no conventional wing tips. Closed wing designs include the annular wing (commonly known as the cylindrical or ring wing), the joined wing, ...
: two wing planes are merged or joined structurally at or near the tips in some way. This stiffens 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 plane to take off and fly, the
Santos-Dumont 14-bis The ''14-bis'' (french: Quatorze-bis), (), also known as ("bird of prey" in French), was a pioneer era, canard-style biplane designed and built by Brazilian aviation pioneer Alberto Santos-Dumont. In 1906, near Paris, the ''14-bis'' made a m ...
, used this configuration. 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 The Blériot III was an early French aeroplane built by pioneer aviators Louis Blériot and Gabriel Voisin. It was later modified and renamed the Blériot IV, but both versions failed to fly. Design and development The Blériot III was radically ...
, 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 transition to horizontal flight. Examples with the wing mounted on top of the fuselage have been proposed but never built. ** Annular (planar): the wing is shaped like a disc with a hole in it. A number of
Lee-Richards annular monoplane During the pioneer years before the First World War, Cedric Lee and G. Tilghman Richards in the UK built and flew a series of aircraft having a novel flat ring-shaped or annular wing. They built both biplane and monoplane types, and in 1913 thei ...
s flew shortly before the First World War. ** Joined wing: a tandem-wing 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.Henderson, William P. and Huffman, Jarrett K.
Aerodynamic characteristics of a tandem wing configuration of a Mach number of 0.30
NASA, October 1975.
The Ligeti Stratos is a rare example. *** Rhomboidal wing: a joined wing consisting of four surfaces in a diamond arrangement. The
Edwards Rhomboidal The Edwards Rhomboidal was an early British aircraft of extremely unorthodox configuration designed by E.W. Edwards. Design and development The Edwards Rhomboidal was an annular wing biplane with identical upper and lower surfaces consisting of ...
biplane of 1911 had both wings in the same plane but failed to fly. Wings can also be characterised as: * Rigid: stiff enough to maintain the
aerofoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
profile in varying conditions of airflow. A rigid wing may have external bracing and/or a fabric covering. *
Flexible Flexible may refer to: Science and technology * Power cord, a flexible electrical cable. ** Flexible cable, an Electrical cable as used on electrical appliances * Flexible electronics * Flexible response * Flexible-fuel vehicle * Flexible rake re ...
: ** The surface may be flexible, typically a thin membrane. Requires external bracing and/or wind pressure to maintain the
aerofoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
shape. Common types include the
Rogallo wing The Rogallo wing is a flexible type of wing. In 1948, Francis Rogallo, a NASA engineer, and his wife Gertrude Rogallo, invented a self-inflating flexible wing they called the Parawing, also known after them as the "Rogallo Wing" and flexible wing ...
,
parafoil A parafoil is a nonrigid (textile) airfoil with an aerodynamic cell structure which is inflated by the wind. Ram-air inflation forces the parafoil into a classic wing cross-section. Parafoils are most commonly constructed out of ripstop nylon. ...
and most
kite A kite is a tethered heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create lift and drag forces. A kite consists of wings, tethers and anchors. Kites often have a bridle and tail to guide the fac ...
s. ** An otherwise rigid structure may be designed to flex, either because it is inherently aeroelastic as in the aeroisoclinic wing, or because shape changes are actively introduced.


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

The aspect ratio is the span divided by the
mean There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value ( magnitude and sign) of a given data set. For a data set, the '' ar ...
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. Structurally efficient, high instantaneous roll rate, low supersonic drag. They tend to be used on fighter aircraft, such as the
Lockheed F-104 Starfighter The Lockheed F-104 Starfighter is an American single-engine, supersonic air superiority fighter which was extensively deployed as a fighter-bomber during the Cold War. Created as a day fighter by Lockheed as one of the "Century Series" of fi ...
, and on very high-speed aircraft including the
North American X-15 The North American X-15 is a hypersonic rocket-powered aircraft. It was operated by the United States Air Force and the National Aeronautics and Space Administration as part of the X-plane series of experimental aircraft. The X-15 set spee ...
. * Moderate aspect ratio: general-purpose wing, very widely used, for example on the
Douglas DC-3 The Douglas DC-3 is a propeller-driven airliner manufactured by Douglas Aircraft Company, which had a lasting effect on the airline industry in the 1930s to 1940s and World War II. It was developed as a larger, improved 14-bed sleeper versi ...
transport. * High aspect ratio: long and slender wing. More efficient aerodynamically, having less induced drag at subsonic speeds. They tend to be used by high-altitude subsonic aircraft such as the
Lockheed U-2 The Lockheed U-2, nicknamed "''Dragon Lady''", is an American single- jet engine, high altitude reconnaissance aircraft operated by the United States Air Force (USAF) and previously flown by the Central Intelligence Agency (CIA). It provides d ...
spy plane and by high-performance sailplanes such as the
Glaser-Dirks DG-500 The Glaser-Dirks DG-500, and later the DG-505, is a two-seat glider of glass-reinforced plastic and carbon fiber reinforced plastic construction, manufactured in the DG Flugzeugbau GmbH in Bruchsal, Germany. It first flew in 1987. Design The ...
. 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. * Constant chord: parallel leading & trailing edges. Simplest to make, and common where low cost is important, such as on the
Piper J-3 Cub The Piper J-3 Cub is an American light aircraft that was built between 1938 and 1947 by Piper Aircraft. The aircraft has a simple, lightweight design which gives it good low-speed handling properties and short-field performance. The Cub is Pi ...
but inefficient as the outer section generates little lift while adding both weight and drag. Sometimes known in North America as the ''
Hershey Bar The Hershey's Milk Chocolate Bar (commonly called the Hershey's Bar, or more simply the Hershey Bar) is a flagship chocolate bar manufactured by The Hershey Company. Hershey refers to it as "The Great American Chocolate Bar". The Hershey Milk Cho ...
'' wing due to its similarity in shape to a popular chocolate bar. * Tapered: wing narrows towards the tip. Structurally and aerodynamically more efficient than a constant chord wing, and easier to make than the elliptical type. **
Trapezoidal A quadrilateral with at least one pair of parallel sides is called a trapezoid () in American and Canadian English. In British and other forms of English, it is called a trapezium (). A trapezoid is necessarily a convex quadrilateral in Eucli ...
: a tapered wing with straight leading and trailing edges: may be unswept or swept. The straight tapered wing is one of the most common wing planforms, as seen on the
Messerschmitt Bf 109 The Messerschmitt Bf 109 is a German World War II fighter aircraft that was, along with the Focke-Wulf Fw 190, the backbone of the Luftwaffe's fighter force. The Bf 109 first saw operational service in 1937 during the Spanish Civil War an ...
. ** Inverse or reverse tapered: wing is widest near the tip. Structurally inefficient, leading to high weight. Flown experimentally on the
XF-91 Thunderceptor The Republic XF-91 Thunderceptor (originally designated XP-91) is a mixed-propulsion prototype interceptor aircraft, developed by Republic Aviation. The aircraft would use a jet engine for most flight, and a cluster of four small rocket engines ...
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 The Westland Lysander is a British army co-operation and liaison aircraft produced by Westland Aircraft that was used immediately before and during the Second World War. After becoming obsolete in the army co-operation role, the aircraft' ...
army cooperation aircraft to increase visibility for the crew. * Constant chord with tapered outer section: common variant seen for example on many
Cessna Cessna () is an American brand of general aviation aircraft owned by Textron Aviation since 2014, headquartered in Wichita, Kansas. Originally, it was a brand of the Cessna Aircraft Company, an American general aviation aircraft manufacturing ...
types. * Elliptical: leading and trailing edges are curved such that the
chord length A chord of a circle is a straight line segment whose endpoints both lie on a circular arc. The infinite line extension of a chord is a secant line, or just ''secant''. More generally, a chord is a line segment joining two points on any curve, for ...
varies elliptically with respect to span. Sometimes mistakenly said to be the most efficient (in
aerodynamics Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dy ...
theory, the term "elliptical" describes the optimal lift distribution over a wing of given span and not its shape), and also difficult to make. Famously used on the
Supermarine Spitfire The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Gri ...
. ** 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 The Seversky P-35 is an American fighter aircraft built by the Seversky Aircraft Company in the late 1930s. A contemporary of the Hawker Hurricane and Messerschmitt Bf 109, the P-35 was the first single-seat fighter in United States Army Air Co ...
. * 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 The Etrich ''Taube'', also known by the names of the various later manufacturers who built versions of the type, such as the Rumpler ''Taube'', was a pre-World War I monoplane aircraft. It was the first military aeroplane to be mass-produced in ...
where its planform was inspired by the ''zanonia'' ('' Alsomitra macrocarpa'') 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. *
Circular Circular may refer to: * The shape of a circle * ''Circular'' (album), a 2006 album by Spanish singer Vega * Circular letter (disambiguation) ** Flyer (pamphlet), a form of advertisement * Circular reasoning, a type of logical fallacy * Circular ...
: approximately circular planform. The
Vought V-173 The Vought V-173 "Flying Pancake" was an American experimental test aircraft built as part of the Vought XF5U program during World War II. Both the V-173 and the XF5U featured an unorthodox "all-wing" design consisting of flat, somewhat disk-sh ...
used large propellers near the tips, which helped to counteract its strong wingtip vortices, and had an outboard tail plane for stability. ** Flying saucer: circular flying wing. Inherently unstable, as the
Avro Canada Avrocar The Avro Canada VZ-9 Avrocar was a VTOL aircraft developed by Avro Canada as part of a secret U.S. military project carried out in the early years of the Cold War. The Avrocar intended to exploit the Coandă effect to provide lift and thrust ...
demonstrated. ** Disc wing: a variant in which the entire disc rotates. Popular on toys such as the
Frisbee A frisbee (pronounced ), also called a flying disc or simply a disc, is a gliding toy or sporting item that is generally made of injection molded, injection-molded plastic and roughly in diameter with a pronounced lip. It is used recreational ...
. ** Flat annular wing: the circle has a hole in, forming a
closed wing A closed wing is a wing that effectively has two main planes which merge at their ends so that there are no conventional wing tips. Closed wing designs include the annular wing (commonly known as the cylindrical or ring wing), the joined wing, ...
(see above). The
Lee-Richards annular monoplane During the pioneer years before the First World War, Cedric Lee and G. Tilghman Richards in the UK built and flew a series of aircraft having a novel flat ring-shaped or annular wing. They built both biplane and monoplane types, and in 1913 thei ...
s flew shortly before the First World War. * 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
Dassault Mirage III The Dassault Mirage III () is a family of single/dual-seat, single-engine, fighter aircraft developed and manufactured by French aircraft company Dassault Aviation. It was the first Western European combat aircraft to exceed Mach number, Mach 2 ...
series. ** Tailed delta: adds a conventional tailplane, to improve handling. Used on the
Mikoyan-Gurevich MiG-21 The Mikoyan-Gurevich MiG-21 (russian: Микоян и Гуревич МиГ-21; NATO reporting name: Fishbed) is a supersonic jet fighter and interceptor aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. Its nickn ...
. ** Cropped delta: wing tips are cut off. This helps avoid tip drag at high angles of attack. The Fairey Delta 1 also had a tail. At the extreme, merges into the "tapered swept" configuration. ** Compound delta or double delta: inner section has a (usually) steeper leading edge sweep as on the
Saab Draken The Saab 35 Draken (; 'The Kite' or 'The Dragon') is a Swedish fighter-interceptor developed and manufactured by Svenska Aeroplan Aktiebolaget (SAAB) between 1955 and 1974. Development of the Saab 35 Draken started in 1948 as the Swedish air fo ...
. This improves the lift at high angles of attack and delays or prevents stalling. By contrast, the
Saab Viggen The Saab 37 Viggen ( Swedish for ''"the Bolt"'' or ''"the Tufted Duck"'' ( see name)) is a retired Swedish single-seat, single-engine, short-medium range combat aircraft. Development work on the type was initiated at Saab in 1952 and, follow ...
has an inner section of reduced sweep to avoid interference from its canard foreplane. ** 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 The Aérospatiale/BAC Concorde () is a retired Franco-British supersonic airliner jointly developed and manufactured by Sud Aviation (later Aérospatiale) and the British Aircraft Corporation (BAC). Studies started in 1954, and France an ...
supersonic transport.


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. * Straight: extends at right angles to the line of flight. The most structurally-efficient wing, it has been common for low-speed designs since the very first days of the
Wright Flyer The ''Wright Flyer'' (also known as the ''Kitty Hawk'', ''Flyer'' I or the 1903 ''Flyer'') made the first sustained flight by a manned heavier-than-air powered and controlled aircraft—an airplane—on December 17, 1903. Invented and flown b ...
. * Swept back (aka "swept wing"): The wing sweeps rearwards from the root to the tip. In early tailless examples, such as the
Dunne aircraft Dunne is an Irish surname, derived from the Irish ''Ó Duinn'' and ''Ó Doinn'', meaning "dark" or "brown." The name Dunne in Ireland is derived from the Ó Duinn and the Ó Doinn Gaelic septs who were based in County Laois, County Meath and Co ...
, this allowed the outer wing section to act like a conventional
empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third e ...
(tail) to provide aerodynamic stability. At
transonic Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transoni ...
speeds swept wings have lower drag, but can handle badly in or near a stall and require high stiffness to avoid
aeroelasticity Aeroelasticity is the branch of physics and engineering studying the interactions between the inertial, elastic, and aerodynamic forces occurring while an elastic body is exposed to a fluid flow. The study of aeroelasticity may be broadly classi ...
at high speeds. Common on high-subsonic and early supersonic designs such as the
Hawker Hunter The Hawker Hunter is a transonic British jet-powered fighter aircraft that was developed by Hawker Aircraft for the Royal Air Force (RAF) during the late 1940s and early 1950s. It was designed to take advantage of the newly developed Rolls-Ro ...
. * 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
aeroelastic flutter Aeroelasticity is the branch of physics and engineering studying the interactions between the inertial, elastic, and aerodynamic forces occurring while an elastic body is exposed to a fluid flow. The study of aeroelasticity may be broadly classif ...
as on the
Sukhoi Su-47 The Sukhoi Su-47 ''Berkut'' (russian: Сухой Су-47 Беркут, translation=Golden Eagle) (NATO reporting name Firkin), also designated S-32 and S-37 (not to be confused with the twin-engined delta canard designButtler, Tony and Gordon, ...
. The
HFB 320 Hansa Jet The HFB 320 Hansa Jet is a twin-engine, ten-seat business jet that was designed and produced by German aircraft manufacturer Hamburger Flugzeugbau between 1964 and 1973. The most recognisable and unconventional feature of the aircraft is its for ...
used forward sweep to prevent the wing spar passing through the cabin. Small
shoulder-wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplane (aeronautics), multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowe ...
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 Aardvark The General Dynamics F-111 Aardvark is a retired supersonic, medium-range, multirole combat aircraft. Production variants of the F-111 had roles that included ground attack (e.g. interdiction), strategic bombing (including nuclear weapons c ...
. *
Oblique wing An oblique wing (also called a slewed wing) is a variable geometry wing concept. On an aircraft so equipped, the wing is designed to rotate on center pivot, so that one tip is swept forward while the opposite tip is swept aft. By changing its swee ...
: 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 The NASA AD-1 was both an aircraft and an associated flight test program conducted between 1979 and 1982 at the NASA Dryden Flight Research Center, Edwards California, which successfully demonstrated an aircraft wing that could be pivoted obli ...
research aircraft.


Sweep variation along span

The angle of a swept wing may also be varied, or cranked, along the span: *
Crescent A crescent shape (, ) is a symbol or emblem used to represent the lunar phase in the first quarter (the "sickle moon"), or by extension a symbol representing the Moon itself. In Hinduism, Lord Shiva is often shown wearing a crescent moon on his ...
: wing outer section is swept less sharply than the inner section, to obtain a best compromise between
transonic Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transoni ...
shock delay and spanwise flow control. Used on the
Handley Page Victor The Handley Page Victor is a British jet-powered strategic bomber developed and produced by Handley Page during the Cold War. It was the third and final '' V bomber'' to be operated by the Royal Air Force (RAF), the other two being the Avr ...
. * Cranked arrow: aerodynamically identical to the compound delta, but with the trailing edge also kinked inwards. Trialled experimentally on the
General Dynamics F-16XL The General Dynamics F-16XL is a derivative of the F-16 Fighting Falcon, with a cranked-arrow delta wing. It was originally conceived as a technology demonstrator, later entered in the United States Air Force's (USAF) Enhanced Tactical Fighte ...
. * M-wing: the inner wing section sweeps forward, and the outer section sweeps backwards. Allows the wing to be highly swept while minimising the undesirable effects of aeroelastic bending. Periodically studied, but never used on an aircraft.Diederich and Foss
''Static Aeroelastic Phenomena of M-, W- and Λ- wings''
NACA 1953.
* W-wing: A reversed M-wing. Proposed for the Blohm & Voss P.188 but studied even less than the M-wing and in the end never used.


Asymmetrical

On a few
asymmetrical aircraft Asymmetrical aircraft have left- and right-hand sides which are not exact mirror images of each other. Although most aircraft are symmetrical, there is no fundamental reason why they must be, and design goals can sometimes be best achieved with an ...
the left and right hand sides are not mirror-images of each other: * Asymmetric layout: the
Blohm & Voss BV 141 The Blohm & Voss BV 141 was a World War II German tactical reconnaissance aircraft, notable for its uncommon structural asymmetry. Although the Blohm & Voss BV 141 performed well, it was never ordered into full-scale production, for reasons t ...
had separate fuselage and crew nacelle offset on either side to give the crew a good field of view. * Asymmetric span: on several Italian fighters such as the
Ansaldo SVA The Ansaldo SVA (named for Savoia-Verduzio-Ansaldo) was a family of Italian reconnaissance biplane aircraft of World War I and the decade after. Originally conceived as a fighter, the SVA was found inadequate for that role. Nevertheless, its ...
, one wing was slightly longer than the other to help counteract engine torque. *
Oblique wing An oblique wing (also called a slewed wing) is a variable geometry wing concept. On an aircraft so equipped, the wing is designed to rotate on center pivot, so that one tip is swept forward while the opposite tip is swept aft. By changing its swee ...
: one wing sweeps forward and the other back. The
NASA AD-1 The NASA AD-1 was both an aircraft and an associated flight test program conducted between 1979 and 1982 at the NASA Dryden Flight Research Center, Edwards California, which successfully demonstrated an aircraft wing that could be pivoted obli ...
had a full-span wing structure with variable sweep.


Tailplanes and foreplanes

The classic
aerofoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
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 - usually on the horizontal stabilizer. * Conventional: "
tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail ( empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyropl ...
" surface at the rear of the aircraft, forming part of the tail or
empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third e ...
. It did not become the convention for some years after the Wrights, with the
Blériot VII The Blériot VII was an early French aeroplane built by Louis Blériot. Design and development Following the success with the tandem wing configuration of the Blériot VI, he continued this line of development. The rear wing of his new design ...
of 1907 being the first successful example. * 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 The Saab 37 Viggen ( Swedish for ''"the Bolt"'' or ''"the Tufted Duck"'' ( see name)) is a retired Swedish single-seat, single-engine, short-medium range combat aircraft. Development work on the type was initiated at Saab in 1952 and, follow ...
in 1967. *
Tandem Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction. The original use of the term in English was in ''tandem harness'', which is used for two ...
: two or more main wings, one behind the other. Both provide significant lift. An example is the
Rutan Quickie The Rutan Quickie is a lightweight single-seat taildragger aircraft of composite construction, configured with tandem wings. The Quickie was primarily designed by Burt Rutan as a low-powered, highly efficient kit-plane. Its tandem wing desig ...
. To provide longitudinal stability, the wings must differ in aerodynamic characteristics: typically the angle of incidence and/or the aerofoils chosen differ between the two wings. The wings on each side may meet at their tips to form a joined wing (see above). * Three surface: both conventional tail and canard auxiliary surfaces. Modern examples include the
Sukhoi Su-33 The Sukhoi Su-33 (russian: Сухой Су-33; NATO reporting name: ''Flanker-D'') is an all-weather carrier-based twin-engine air superiority fighter designed by Sukhoi and manufactured by Komsomolsk-on-Amur Aircraft Production Association ...
, while pioneer examples include the
Voisin-Farman I The 1907 Voisin biplane (designated the Voisin II by the 1913 edition of ''Jane's All the World's Aircraft''), was the first successful powered aircraft designed by aeronautical engineer and manufacturer Gabriel Voisin. It was used by the F ...
. * Outboard tail: split in two, with each half mounted on a short boom just behind and outboard of a wing tip. It comprises outboard horizontal stabilisers (OHS) and may or may not include additional boom-mounted vertical stabilisers (fins). In this position, the tail surfaces interact constructively with the wingtip vortices to significantly reduce drag. Used for the Scaled Composites
SpaceShipOne SpaceShipOne is an experimental air-launched rocket-powered aircraft with sub-orbital spaceflight capability at speeds of up to 3,000 ft/s (900 m/s, 3240 km/h), using a hybrid rocket motor. The design features a unique " feathering ...
. * 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 The Short SB.4 Sherpa was an experimental aircraft designed and produced by the British aircraft manufacturer Short Brothers. Only a single example was ever produced. The Sherpa was developed during the 1950s for the purpose of testing a nove ...
whose whole wing tip sections acted as
elevon Elevons or tailerons are aircraft control surfaces that combine the functions of the elevator (used for pitch control) and the aileron (used for roll control), hence the name. They are frequently used on tailless aircraft such as flying wings. A ...
s. Alternatively the aerofoil profile may be modified to provide inherent stability, as on the
Dunne D.5 __NOTOC__ The Dunne D.5 was a British experimental aircraft built in 1910. A tailless swept-wing biplane, it was designed by J. W. Dunne and built by Short Brothers at Leysdown for his company, the Blair Atholl Aeroplane Syndicate Ltd. Like it ...
. Aircraft having a tailplane but no vertical tail fin have also been described as "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. * Dihedral: the tips are higher than the root as on the
Santos-Dumont 14-bis The ''14-bis'' (french: Quatorze-bis), (), also known as ("bird of prey" in French), was a pioneer era, canard-style biplane designed and built by Brazilian aviation pioneer Alberto Santos-Dumont. In 1906, near Paris, the ''14-bis'' made a m ...
, giving a shallow 'V' shape when seen from the front. Adds lateral stability. * Anhedral or catahedral: the tips are lower than the root, as on the first
Wright Flyer The ''Wright Flyer'' (also known as the ''Kitty Hawk'', ''Flyer'' I or the 1903 ''Flyer'') made the first sustained flight by a manned heavier-than-air powered and controlled aircraft—an airplane—on December 17, 1903. Invented and flown b ...
; 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. The
Sopwith Camel The Sopwith Camel is a British First World War single-seat biplane fighter aircraft that was introduced on the Western Front in 1917. It was developed by the Sopwith Aviation Company as a successor to the Sopwith Pup and became one of the ...
had a flat upper wing and dihedral on the lower wing, while the
Hanriot HD-1 The Hanriot HD.1 was a French World War I single-seat fighter aircraft. Rejected for service with French squadrons in favour of the SPAD S.VII, the type was supplied to the Belgian Army′s (Belgian Military Aviation) and the (Military Aviatio ...
had dihedral on the upper wing but none on the lower. In a cranked or polyhedral wing the dihedral angle varies along the span. (Note that the description "cranked" varies in usage. See also Cranked arrow planform.) *
Gull wing The gull wing is an aircraft wing configuration, known also as ''Pulaski wings'', with a prominent bend in the wing inner section towards the wing root. Its name is derived from the seabirds which it resembles. Numerous aircraft have incorpora ...
: 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 The Polikarpov I-153 ''Chaika'' (Russian ''Чайка'', "Seagull") was a late 1930s Soviet biplane fighter. Developed as an advanced version of the I-15 with a retractable undercarriage, the I-153 fought in the Soviet-Japanese combats in Mon ...
. * Inverted gull wing: 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 while allowing a raised fuselage, as on the German
Junkers Ju 87 The Junkers Ju 87 or Stuka (from ''Sturzkampfflugzeug'', "dive bomber") was a German dive bomber and ground-attack aircraft. Designed by Hermann Pohlmann, it first flew in 1935. The Ju 87 made its combat debut in 1937 with the Luftwaffe's ...
''Stuka'' dive bomber. * Cranked or canted tip: tip section dihedral differs from the main wing. The tips may have upwards dihedral as on the
F-4 Phantom II The McDonnell Douglas F-4 Phantom II is an American tandem two-seat, twin-engine, all-weather, long-range supersonic jet interceptor and fighter-bomber originally developed by McDonnell Aircraft for the United States Navy.Swanborough and ...
or downwards anhedral as on the Northrop XP-56 Black Bullet. * 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.


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 A flying wing is a tailless fixed-wing aircraft that has no definite fuselage, with its crew, payload, fuel, and equipment housed inside the main wing structure. A flying wing may have various small protuberances such as pods, nacelles, blis ...
: 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 The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying wi ...
. * Blended body or blended wing-body: a smooth transition occurs between wing and fuselage, with no hard dividing line. Reduces
wetted area The surface area that interacts with the working fluid or gas. In maritime industry, maritime use, the wetted area is the area of the hull (watercraft) which is immersed in water. This has a direct relationship on the overall hydrodynamic drag of ...
and can also reduce interference between airflow over the wing root and any adjacent body, in both cases reducing drag. The
Lockheed SR-71 The Lockheed SR-71 "Blackbird" is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed and manufactured by the American aerospace company Lockheed Corporation. It was operated by the United States Air Force ...
spyplane exemplifies this approach. *
Lifting body A lifting body is a fixed-wing aircraft or spacecraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage ...
: 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. Some designs may fall into multiple categories depending on interpretation, for example many
UAV An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
s or drones can be seen either as a tailless blended wing-body or as a flying wing with a deep centre 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 A powered lift aircraft takes off and lands vertically under engine power but uses a fixed wing for horizontal flight. Like helicopters, these aircraft do not need a long runway to take off and land, but they have a speed and performance simila ...
.


Variable planform

*
Variable-sweep wing A variable-sweep wing, colloquially known as a "swing wing", is an airplane wing, or set of wings, that may be swept back and then returned to its original straight position during flight. It allows the aircraft's shape to be modified in fli ...
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 The Beechcraft Starship is a twin-turboprop six- to eight-passenger pressurized business aircraft produced by Beech Aircraft Corporation. Development Development of the Starship began in 1979 when Beech decided to explore designs for a succe ...
, only the canard foreplanes have variable sweep. *
Oblique wing An oblique wing (also called a slewed wing) is a variable geometry wing concept. On an aircraft so equipped, the wing is designed to rotate on center pivot, so that one tip is swept forward while the opposite tip is swept aft. By changing its swee ...
: a single full-span wing pivots about its midpoint, as used on the
NASA AD-1 The NASA AD-1 was both an aircraft and an associated flight test program conducted between 1979 and 1982 at the NASA Dryden Flight Research Center, Edwards California, which successfully demonstrated an aircraft wing that could be pivoted obli ...
, 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. * Detachable wing. The WS110A study proposed a long wing for subsonic takeoff and cruise, which then detached the outer panels to drop away, leaving a short-span wing for supersonic flight. (See also Slip wing below.) * 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 Gérin Varivol biplane, which flew in 1936, extended the leading and trailing edges to increase wing area. * 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 The North American Aviation XB-70 Valkyrie was the prototype version of the planned B-70 nuclear-armed, deep-penetration supersonic strategic bomber for the United States Air Force Strategic Air Command. Designed in the late 1950s by North Ame ...
wing folded down during supersonic cruise. (Many 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.)


Variable section

* 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 A short take-off and vertical landing aircraft (STOVL aircraft) is a fixed-wing aircraft that is able to take off from a short runway (or take off vertically if it does not have a heavy payload) and land vertically (i.e. with no runway). The ...
performance, merges into the
powered lift A powered lift aircraft takes off and lands vertically under engine power but uses a fixed wing for horizontal flight. Like helicopters, these aircraft do not need a long runway to take off and land, but they have a speed and performance simila ...
category. * Variable camber: the leading and/or trailing edge sections of the whole wing pivot to increase the effective camber of the wing and sometimes also its area. 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.Boyne, W.J.; ''The best of Wings magazine'', Brassey's (2001)


Polymorphism

A polymorphic wing is able to change the number of planes in flight. The
Nikitin-Shevchenko IS The Nikitin-Schyevchyenko IS series, (''Istrebitel Skladnoi'' – folding fighter), were single seat polymorphic fighters designed and produced in the USSR from 1938. Development Nikitin's test pilot, Vladimir Vasiloyevich Schyevchyenko, in ...
"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 first flown on the experimental Hillson Bi-mono.


Minor independent surfaces

Aircraft may have additional minor aerodynamic surfaces. Some of these are treated as part of the overall wing configuration: *
Winglet Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...
: a small fin at the wingtip, usually turned upwards. Reduces the size of vortices shed by the wingtip, and hence also tip drag. *
Strake On a vessel's hull, a strake is a longitudinal course of planking or plating which runs from the boat's stempost (at the bows) to the sternpost or transom (at the rear). The garboard strakes are the two immediately adjacent to the keel on ea ...
: 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 A chine () is a steep-sided coastal gorge where a river flows to the sea through, typically, soft eroding cliffs of sandstone or clays. The word is still in use in central Southern England—notably in East Devon, Dorset, Hampshire and the Is ...
: sharp-edged profile running along the fuselage. When used aerodynamically it is extended outwards to form a lifting surface, typically blending into the main wing. As well as improving low speed (high angle of attack) handling, provides extra lift at high supersonic speeds for minimal increase in drag. Seen on the
Lockheed SR-71 Blackbird The Lockheed SR-71 "Blackbird" is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed and manufactured by the American aerospace company Lockheed Corporation. It was operated by the United States Air Force ...
. * 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.


Additional minor features

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


High lift

High-lift device In aircraft design and aerospace engineering, a high-lift device is a component or mechanism on an aircraft's wing that increases the amount of lift produced by the wing. The device may be a fixed component, or a movable mechanism which is deplo ...
s maintain lift at low speeds and delay the stall to allow slower takeoff and landing speeds: * Slat and
slot Slot, the slot or Slots may refer to: People * Arne Slot (born 1978), Dutch footballer * Gerrie Slot (born 1954), Dutch cyclist * Hanke Bruins Slot (born 1977), Dutch politician * Tonny Bruins Slot (born 1947), Dutch association football coach ...
: a Leading edge slat is a small aerofoil extending in front of the main leading edge. The spanwise gap behind it forms a leading-edge slot. Air flowing up through the slot is deflected backwards by the slat to flow over the wing, allowing the aircraft to fly at lower air speeds without flow separation or stalling. A slat may be fixed or retractable. *
Flap Flap may refer to: Arts, entertainment, and media * ''Flap'' (film), a 1970 American film * Flap, a boss character in the arcade game ''Gaiapolis'' * Flap, a minor character in the film '' Little Nemo: Adventures in Slumberland'' Biology and he ...
: a hinged aerodynamic surface, usually on the trailing edge, which is rotated downwards to generate extra lift and drag. Types include plain, slotted, and split. Some, such as
Fowler Flaps A flap is a high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing ...
, also extend rearwards to increase wing area. The
Krueger flap Krueger flaps, or Krüger flaps, are lift enhancement devices that may be fitted to the leading edge of an aircraft wing. Unlike slats or droop flaps, the main wing upper surface and its nose is not changed. Instead, a portion of the lower wing ...
is a leading-edge device. *
Cuff A cuff is a layer of fabric at the lower edge of the sleeve of a garment (shirt, coat, jacket, etc.) at the wrist, or at the ankle end of a trouser leg. The function of turned-back cuffs is to protect the cloth of the garment from fraying, an ...
: an extension to the leading edge which modifies the aerofoil section, typically to improve low-speed characteristics.


Spanwise flow control

On a swept wing, air tends to flow sideways as well as backwards and reducing this can improve the efficiency of the wing: *
Wing fence Wing fences, also known as boundary layer fences and potential fences are fixed aerodynamic devices attached to aircraft wings. Often seen on swept-wing aircraft, wing fences are flat plates fixed to the upper surfaces parallel to the wing ch ...
: a flat plate extending along the wing chord and for a short distance vertically. Used to control spanwise airflow over the wing. * Dogtooth leading edge: creates a sharp discontinuity in the airflow over the wing, disrupting spanwise flow. * Notched leading edge: acts like a dogtooth.''Wing vortex devices''
/ref>


Vortex creation

Vortex devices maintain airflow at low speeds and delay the stall, by creating a vortex which re-energises the
boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary cond ...
close to the wing. *
Vortex generator A vortex generator (VG) is an aerodynamic device, consisting of a small vane usually attached to a lifting surface (or airfoil, such as an aircraft wing) or a rotor blade of a wind turbine.
: small triangular protrusion on the upper leading wing surface; usually, several are spaced along the span of the wing. Vortex generators create additional drag at all speeds. *
Vortilon Vortilons are fixed aerodynamic devices on aircraft wings used to improve handling at low speeds. The vortilon was invented by aerodynamicists working at Douglas Aircraft who had previously developed the engine pylons for the Douglas DC-8. The o ...
: a flat plate attached to the underside of the wing near its outer leading edge, roughly parallel to normal airflow. At low speeds, tip effects cause a local spanwise flow which is deflected by the vortilon to form a vortex passing up and over the wing. *
Leading-edge root extension A leading-edge extension (LEX) is a small extension to an aircraft wing surface, forward of the leading edge. The primary reason for adding an extension is to improve the airflow at high angles of attack and low airspeeds, to improve handling a ...
(LERX): generates a strong vortex over the wing at high angles of attack, but unlike vortex generators it can also increase lift at such high angles, while creating minimal drag in level flight.


Drag reduction

* Anti-shock body: a streamlined pod shape added to the leading or trailing edge of an aerodynamic surface, to delay the onset of
shock stall A shock stall is a stall created when the airflow over an aircraft's wings is disturbed by shock waves formed when flying at or above the aircraft's drag divergence Mach number The drag-divergence Mach number (not to be confused with critical Mach ...
and reduce transonic
wave drag In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (re ...
. Sometimes called a ''Küchemann carrot''. * Fairings of various kinds, such as blisters, pylons and wingtip pods, containing equipment which cannot fit inside the wing, and whose only aerodynamic purpose is to reduce the drag created by the equipment. * Fillet, a type of fairing: a small curved infill at the junction of two surfaces, such as a wing and fuselage, blending them smoothly together to reduce drag.


See also

* Wing § Design features *
Aircraft design process The aircraft design process is a loosely defined method used to balance many competing and demanding requirements to produce an aircraft that is strong, lightweight, economical and can carry an adequate payload while being sufficiently reliable to ...


References


Notes


Bibliography

* Kermode, A. C.; ''Mechanics of Flight'', Eighth (metric) edition, Pitman, London, 1972. * Taylor, John W. R. ''The Lore of Flight'', Universal Books, London, 1990. . *
Archive
.


External links



��''Flight'' article on the merits of wing position {{DEFAULTSORT:Wing Configuration Aircraft configurations Aircraft wing design de:Tragfläche