Elevator (aircraft)
From Wikipedia, the free encyclopedia
- For other meanings of "elevator" see Elevator (disambiguation).
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 angle of attack will cause a greater lift to be produced by the profile of the wing, and (if no power is added or available), a slowing of the aircraft. A decreased angle of attack will produce an increase in speed (a dive). There may be separate elevators on each side, operating in unison. The elevator or elevators may be the only pitch control surface present, or may be hinged to a fixed or adjustable surface called a stabilizer.
The rearwing which elevators are attached to have the opposite affect to a wing, which is they create a downward pressure which counters the moment created by the centre of gravity pivoting aroung the centre of pressure. An elevator decreases or increases the lift created by this wing. A decreased lift forces the tail down and the nose up so you climb, increased lift lifts the tail up and forces the nose down.
In some aircraft the elevator is in the front, ahead of the wing; this type of configuration is called a canard, the French word for duck. The Wright Brothers' early aircraft were of this type. The canard type is more efficient, since the forward surface produces upward lift. The main wing is also less likely to stall, as the forward control surface is configured to stall before the wing, causing a pitch down and reducing the angle of attack of the wing.
Supersonic aircraft lack elevators, because early supersonic flight research revealed that shock waves generated on the tailplane rendered hinged elevators ineffective. Instead, supersonic aircraft combine both aileron and elevator inputs into one control surface, called an elevon.
