Flap (aeronautics)
This increases lift-induced drag which can be beneficial during approach and landing because it allows the aircraft to descend at a steeper angle.
The Fowler, Fairey-Youngman and Gouge types of flap increase the wing area in addition to changing the camber.
The de Havilland DH.88 Comet racer had flaps running beneath the fuselage and forward of the wing trailing edge.
The amount of flap used on takeoff is specific to each type of aircraft, and the manufacturer will suggest limits and may indicate the reduction in climb rate to be expected.
The Cessna 172S Pilot Operating Handbook recommends 10° of flaps on takeoff, when the ground is soft or it is a short runway, otherwise 0 degrees is used.
[citation needed] At higher speeds a negative flap setting is used to reduce the nose-down pitching moment.
[citation needed] Negative flap may also be used during the initial stage of an aerotow launch and at the end of the landing run in order to maintain better control by the ailerons.
[4] Some flap track fairings are designed to act as anti-shock bodies, which reduce drag caused by local sonic shock waves where the airflow becomes transonic at high speeds.
Interference in the go-around case while the flaps are still fully deployed can cause increased drag which must not compromise the climb gradient.
[12] Additionally, lift across the entire chord of the primary airfoil is greatly increased as the velocity of air leaving its trailing edge is raised, from the typical non-flap 80% of freestream, to that of the higher-speed, lower-pressure air flowing around the leading edge of the slotted flap.
First used on the Martin 146 prototype in 1935, it entered production on the 1937 Lockheed Super Electra,[15] and remains in widespread use on modern aircraft, often with multiple slots.
[17] When not in use, it has more drag than other types, but is more effective at creating additional lift than a plain or split flap, while retaining their mechanical simplicity.
[18] A type of split flap that slides backward along curved tracks that force the trailing edge downward, increasing chord and camber without affecting trim or requiring any additional mechanisms.
[citation needed] The Zap flap was invented by Edward F. Zaparka while he was with Berliner/Joyce and tested on a General Airplanes Corporation Aristocrat in 1932 and on other types periodically thereafter, but it saw little use on production aircraft other than on the Northrop P-61 Black Widow.
[23] Invented by Werner Krüger in 1943 and evaluated in Goettingen, Krueger flaps are found on many modern swept wing airliners.
A small fixed perpendicular tab of between 1 and 2% of the wing chord, mounted on the high pressure side of the trailing edge of an airfoil.
It was named for racing car driver Dan Gurney who rediscovered it in 1971, and has since been used on some helicopters such as the Sikorsky S-76B to correct control problems without having to resort to a major redesign.
Late marks of the Supermarine Spitfire used a bead on the trailing edge of the elevators, which functioned in a similar manner.
The entire leading edge of the wing rotates downward, effectively increasing camber and also slightly reducing chord.
[24][25] Most commonly found on fighters with very thin wings unsuited to other leading edge high lift devices.
Their purpose is to increase lift during low speed operations such as take-off, initial climb, approach and landing.
While testing was done in Britain and Germany before the Second World War,[26] and flight trials started, the first production aircraft with blown flaps was not until the 1957 Lockheed T2V SeaStar.
A modern interpretation of wing warping, internal mechanical actuators bend a lattice that changes the airfoil shape.
The Continuous Trailing-Edge Flap (CTEF) uses components to change blade camber during flight, eliminating mechanical hinges in order to improve system reliability.
