Editing Flight control surfaces (section)

==Secondary control surfaces==
[[File:klm.fokker70.airbrakes.arp.750pix.jpg|thumb|right|[[KLM]] [[Fokker 70]], showing position of flap and liftdumper flight controls. The liftdumpers are the lifted cream-coloured panels on the wing upper surface (in this picture there are five on the right wing). The flaps are the large drooped surfaces on the trailing edge of the wing.]]

=== Spoilers ===
{{Main|Spoiler (aeronautics)|Spoileron}}
[[File:747-8I-trailing-wing-surfaces.jpg|thumb|right|Wing trailing edge flight control surfaces of a [[Boeing 747-8I|Boeing 747-8]]. Top left: All surfaces at neutral position; Top middle: Right [[Adverse yaw|aileron]] is lowered; Top right:  [[Spoiler (aeronautics)|spoilers]] raised during flight; Middle row: Fowler flaps extended (left), extended more (middle), hinged with inboard slotted part hinged even more (right); Bottom row: spoilers raised during landing]]
On low drag aircraft such as [[sailplanes]], [[Spoiler (aeronautics)|spoilers]] are used to disrupt airflow over the wing and greatly reduce lift.  This allows a glider pilot to lose altitude without gaining excessive airspeed. Spoilers are sometimes called "lift dumpers". Spoilers that can be used asymmetrically are called [[spoileron]]s and can affect an aircraft's roll.

=== Flaps ===
{{main|Flap (aircraft)}}

[[Flap (aircraft)|Flaps]] are mounted on the trailing edge on the inboard section of each wing (near the wing roots). They are deflected down to increase the effective curvature of the wing. Flaps raise the [[Lift coefficient|maximum lift coefficient]] of the aircraft and therefore reduce its stalling speed.<ref>Clancy, L.J. ''Aerodynamics'' Chapter 6</ref>  They are used during low speed, high angle of attack flight including take-off and descent for landing. Some aircraft are equipped with "[[flaperon]]s", which are more commonly called "inboard ailerons"{{Citation needed|date=October 2007}}.  These devices function primarily as ailerons, but on some aircraft, will "droop" when the flaps are deployed, thus acting as both a flap and a roll-control inboard aileron.

=== Slats ===
{{Main|Leading edge slats}}

[[Leading edge slats|Slats]], also known as ''leading edge devices'', are extensions to the front of a wing for lift augmentation, and are intended to reduce the stalling speed by altering the airflow over the wing. Slats may be fixed or retractable - fixed slats (e.g. as on the [[Fieseler Fi 156|Fieseler Fi 156 Storch]]) give excellent slow speed and [[STOL]] capabilities, but compromise higher speed performance. Retractable slats, as seen on most airliners, provide reduced stalling speed for take-off and landing, but are retracted for cruising.

=== Air brakes ===
[[File:Eurowings bae146-300 d-aewb arp.jpg|thumb|right|Air brakes on the rear fuselage of a [[Eurowings]] [[British Aerospace 146|BAe 146-300]]]]
{{Main|Air brake (aeronautics)}}

Air brakes are used to increase drag. Spoilers might act as air brakes, but are not pure air brakes as they also function as lift-dumpers or in some cases as roll control surfaces. Air brakes are usually surfaces that deflect outwards from the fuselage (in most cases symmetrically on opposing sides) into the airstream in order to increase form-drag. As they are in most cases located elsewhere on the aircraft, they do not directly affect the lift generated by the wing. Their purpose is to slow down the aircraft. They are particularly useful when a high rate of descent is required. They are common on high performance military aircraft as well as civilian aircraft, especially those lacking reverse thrust capability.