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Supercritical airfoil A supercritical airfoil is anairfoildesigned, primarily, to delay the

onset ofwave dragin thetransonicspeed range.

Supercritical airfoils are characterized by their flattened uppersurface, highlycambered(curved) aft section, and greaterleadingedgeradius compared with traditional airfoil shapes.

It has since been mainly applied to increase the fuel efficiency ofmany high subsonic aircraft. The supercritical airfoil shape is

incorporated into the design of a supercritical wing.

Due to the airfoil shape used, supercritical wings experience theseproblems (traditional airfoil induced excessivewave dragand a form

of stability loss calledMach tuck.) less severely and at much higherspeeds, thus allowing the wing to maintain high performance at

speeds closer to Mach 1.

Supercritical airfoils feature four main benefits: they have ahigherdrag divergence Mach number,they developshock

wavesfurther aft than traditional airfoils, they greatly reduce shock-

inducedboundary layerseparation, and their geometry allows for

more efficient wing design (e.g., a thicker wing and/or reduced wing

sweep, each of which may allow for a lighter wing). In addition to improved transonic performance, a supercritical wing's

enlarged leading edge gives it excellent high-lift characteristics.

Consequently, aircraft utilizing a supercritical wing have superior

takeoff and landing performance. This makes the supercritical wing a

favorite for designers of cargo transport aircraft. The supercritical airfoils were designed in the 1960s, by

thenNASAengineerRichard Whitcomb, and were first tested on a

modifiedNorth American T-2C Buckeye. A notable example of one such heavy-lift aircraft that uses a

supercritical wing is theC-17 Globemaster III. Others are Airbus

A300andBoeing 777to theMcDonnell Douglas AV-8B Harrier II.

http://en.wikipedia.org/wiki/Airfoilhttp://en.wikipedia.org/wiki/Airfoilhttp://en.wikipedia.org/wiki/Airfoilhttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Transonichttp://en.wikipedia.org/wiki/Transonichttp://en.wikipedia.org/wiki/Transonichttp://en.wikipedia.org/wiki/Camber_(aerodynamics)http://en.wikipedia.org/wiki/Camber_(aerodynamics)http://en.wikipedia.org/wiki/Camber_(aerodynamics)http://en.wikipedia.org/wiki/Leading_edgehttp://en.wikipedia.org/wiki/Leading_edgehttp://en.wikipedia.org/wiki/Leading_edgehttp://en.wikipedia.org/wiki/Leading_edgehttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Mach_tuckhttp://en.wikipedia.org/wiki/Mach_tuckhttp://en.wikipedia.org/wiki/Mach_tuckhttp://en.wikipedia.org/wiki/Drag_divergence_Mach_numberhttp://en.wikipedia.org/wiki/Drag_divergence_Mach_numberhttp://en.wikipedia.org/wiki/Drag_divergence_Mach_numberhttp://en.wikipedia.org/wiki/Shock_waveshttp://en.wikipedia.org/wiki/Shock_waveshttp://en.wikipedia.org/wiki/Shock_waveshttp://en.wikipedia.org/wiki/Shock_waveshttp://en.wikipedia.org/wiki/Boundary_layerhttp://en.wikipedia.org/wiki/Boundary_layerhttp://en.wikipedia.org/wiki/Boundary_layerhttp://en.wikipedia.org/wiki/NASAhttp://en.wikipedia.org/wiki/NASAhttp://en.wikipedia.org/wiki/NASAhttp://en.wikipedia.org/wiki/Richard_Whitcombhttp://en.wikipedia.org/wiki/Richard_Whitcombhttp://en.wikipedia.org/wiki/Richard_Whitcombhttp://en.wikipedia.org/wiki/North_American_T-2_Buckeyehttp://en.wikipedia.org/wiki/North_American_T-2_Buckeyehttp://en.wikipedia.org/wiki/North_American_T-2_Buckeyehttp://en.wikipedia.org/wiki/C-17_Globemaster_IIIhttp://en.wikipedia.org/wiki/C-17_Globemaster_IIIhttp://en.wikipedia.org/wiki/C-17_Globemaster_IIIhttp://en.wikipedia.org/wiki/Airbus_A300http://en.wikipedia.org/wiki/Airbus_A300http://en.wikipedia.org/wiki/Airbus_A300http://en.wikipedia.org/wiki/Boeing_777http://en.wikipedia.org/wiki/Boeing_777http://en.wikipedia.org/wiki/Boeing_777http://en.wikipedia.org/wiki/McDonnell_Douglas_AV-8B_Harrier_IIhttp://en.wikipedia.org/wiki/McDonnell_Douglas_AV-8B_Harrier_IIhttp://en.wikipedia.org/wiki/McDonnell_Douglas_AV-8B_Harrier_IIhttp://en.wikipedia.org/wiki/Boeing_777http://en.wikipedia.org/wiki/Airbus_A300http://en.wikipedia.org/wiki/Airbus_A300http://en.wikipedia.org/wiki/C-17_Globemaster_IIIhttp://en.wikipedia.org/wiki/North_American_T-2_Buckeyehttp://en.wikipedia.org/wiki/Richard_Whitcombhttp://en.wikipedia.org/wiki/NASAhttp://en.wikipedia.org/wiki/Boundary_layerhttp://en.wikipedia.org/wiki/Shock_waveshttp://en.wikipedia.org/wiki/Shock_waveshttp://en.wikipedia.org/wiki/Drag_divergence_Mach_numberhttp://en.wikipedia.org/wiki/Mach_tuckhttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Leading_edgehttp://en.wikipedia.org/wiki/Leading_edgehttp://en.wikipedia.org/wiki/Camber_(aerodynamics)http://en.wikipedia.org/wiki/Transonichttp://en.wikipedia.org/wiki/Wave_draghttp://en.wikipedia.org/wiki/Airfoil

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Supercritical airfoil Mach Number/pressure coefficient diagram. The sudden

increase in pressure coefficient at mid chord is due to the shock. (y-axis :Mach

number (or pressure coefficient, negative up); x-axis: position along chord, leading

edge left)

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Some Pictures

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Split Flap

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Strake A strakeis anaerodynamicsurface generally mounted on

thefuselageof anaircraftto improve the flight characteristics either

by controlling the airflow (acting as largevortex generators) or by

simple stabilising effect.

Leading edge root extensions(LERX) are also sometimes referred toas wing strakes. A leading-edge root extensions (LERX) is a smallfillet, typically

roughly triangular in shape, running forward from the leading edge

of thewing rootto a point along the fuselage.

http://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Fuselagehttp://en.wikipedia.org/wiki/Fuselagehttp://en.wikipedia.org/wiki/Fuselagehttp://en.wikipedia.org/wiki/Aircrafthttp://en.wikipedia.org/wiki/Aircrafthttp://en.wikipedia.org/wiki/Aircrafthttp://en.wikipedia.org/wiki/Vortex_generatorhttp://en.wikipedia.org/wiki/Vortex_generatorhttp://en.wikipedia.org/wiki/Vortex_generatorhttp://en.wikipedia.org/wiki/Leading_edge_root_extensionhttp://en.wikipedia.org/wiki/Leading_edge_root_extensionhttp://en.wikipedia.org/wiki/Fillet_(mechanics)http://en.wikipedia.org/wiki/Fillet_(mechanics)http://en.wikipedia.org/wiki/Fillet_(mechanics)http://en.wikipedia.org/wiki/Wing_roothttp://en.wikipedia.org/wiki/Wing_roothttp://en.wikipedia.org/wiki/Wing_roothttp://en.wikipedia.org/wiki/Wing_roothttp://en.wikipedia.org/wiki/Fillet_(mechanics)http://en.wikipedia.org/wiki/Leading_edge_root_extensionhttp://en.wikipedia.org/wiki/Vortex_generatorhttp://en.wikipedia.org/wiki/Aircrafthttp://en.wikipedia.org/wiki/Fuselagehttp://en.wikipedia.org/wiki/Aerodynamics

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On a modernfighter aircraftLERX provide usableairflowover thewing at highangles of attack, so delaying the stall and consequent

loss of lift. In cruising flight the effect of the LERX is minimal.

However at high angles of attack, as often encountered in a dog

fightor during takeoff and landing, the LERX generates a high-speedvortexthat attaches to the top of the wing. The vortex action

maintains a smooth airflow over the wing surface well past the

normalstallpoint at which the airflow would otherwise break up,

thus sustaining lift at very high angles.

Condensation vortex flows along an F/A-18's LERX

http://en.wikipedia.org/wiki/Fighter_aircrafthttp://en.wikipedia.org/wiki/Fighter_aircrafthttp://en.wikipedia.org/wiki/Fighter_aircrafthttp://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Angle_of_attackhttp://en.wikipedia.org/wiki/Angle_of_attackhttp://en.wikipedia.org/wiki/Angle_of_attackhttp://en.wikipedia.org/wiki/Dog_fighthttp://en.wikipedia.org/wiki/Dog_fighthttp://en.wikipedia.org/wiki/Dog_fighthttp://en.wikipedia.org/wiki/Dog_fighthttp://en.wikipedia.org/wiki/Vortexhttp://en.wikipedia.org/wiki/Vortexhttp://en.wikipedia.org/wiki/Vortexhttp://en.wikipedia.org/wiki/Stall_(flight)http://en.wikipedia.org/wiki/Stall_(flight)http://en.wikipedia.org/wiki/Stall_(flight)http://en.wikipedia.org/wiki/Stall_(flight)http://en.wikipedia.org/wiki/Vortexhttp://en.wikipedia.org/wiki/Dog_fighthttp://en.wikipedia.org/wiki/Dog_fighthttp://en.wikipedia.org/wiki/Angle_of_attackhttp://en.wikipedia.org/wiki/Aerodynamicshttp://en.wikipedia.org/wiki/Fighter_aircraft

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