Control surfaces

From FlightGear wiki
Revision as of 15:52, 14 March 2009 by Mdsmith2 (talk | contribs)
Jump to navigation Jump to search

Ailerons

Ailerons (red) on the wings of a Cessna C172

Ailerons are hinged control surfaces attached to the trailing edge of the wing of a fixed-wing aircraft. The ailerons are used to control the aircraft in roll. The two ailerons are typically interconnected so that one goes down when the other goes up: the downgoing aileron increases the lift on its wing while the upgoing aileron reduces the lift on the other wing, producing a rolling moment about the aircraft's longitudinal axis. The word aileron is French for "little wing."

Elevators

Elevators on the tail of a Boeing 777-200

Elevators are control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. An increased wing angle of attack will cause a greater lift to be produced by the profile of the wing, and a slowing of the aircraft. A decreased angle of attack will produce an increase in speed (a dive). The elevators may be the only pitch control surface present (and are then called a stabilator), or may be hinged to a fixed or adjustable surface called a stabilizer.

Flaps

Flaps (red) on the wings of a Cessna C172

Flaps are hinged surfaces on the trailing edge of the wings of a fixed-wing aircraft. As flaps are extended the stalling speed of the aircraft is reduced. Flaps are also used on the leading edge of the wings of some high-speed jet aircraft, where they may be called slats.

Flaps reduce the stalling speed by increasing the camber of the wing and thereby increasing the maximum lift coefficient. Some trailing edge flaps also increase the area of the wing and, for any given aircraft weight, this reduces the stalling speed. The Fowler flap is an example of one which increases the area of the wing.

Rudder

Rudder (red) on the tail of a Cessna C172

On an aircraft, the rudder is called a "control surface" along with the rudder-like elevator (attached to horizontal tail structure) and ailerons (attached to the wings) that control pitch and roll. The rudder is usually attached to the fin (or vertical stabilizer) which allows the pilot to control yaw in the vertical axis, i.e. change the horizontal direction in which the nose is pointing. The rudder's direction is manipulated with the movement of foot pedals by the pilot.