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Elevators areflight control surfaces, usually at the rear of anaircraft, which control the aircraft'spitch, and therefore theangle of attack and the lift of the wing. The elevators are usually hinged to thetailplane or horizontalstabilizer. They may be the only pitch control surface present, and are sometimes located at the front of the aircraft (early airplanes andcanards) or integrated into a rear "all-moving tailplane", also called a slab elevator orstabilator.
The elevator is a usable up and down system that controls the plane,horizontal stabilizer usually creates adownward force which balances the nose downmoment created by the wing lift force, which typically applies at a point (the wing center of lift) situatedaft of the airplane'scenter of gravity. The effects ofdrag and changing the enginethrust may also result in pitch moments that need to be compensated with the horizontal stabilizer.
Both the horizontal stabilizer and the elevator contribute to pitch stability, but only the elevators provide pitch control.[1] They do so by decreasing or increasing the downward force created by the stabilizer:
On many low-speed aircraft, atrim tab is present at the rear of the elevator, which the pilot can adjust to eliminate forces on thecontrol column at the desired attitude and airspeed.[2]Supersonic aircraft usually have all-moving tailplanes (stabilators), because shock waves generated on the horizontal stabilizer greatly reduce the effectiveness of hinged elevators during supersonic flight.Delta winged aircraft combineailerons and elevators –and their respective control inputs– into one control surface called anelevon.
Elevators are usually part of the tail, at the rear of an aircraft. In some aircraft, pitch-control surfaces are in the front, ahead of the wing. In a two-surface aircraft this type of configuration is called acanard (theFrench word forduck) or atandem wing. TheWright Brothers' early aircraft were of the canard type;Mignet Pou-du-Ciel andRutan Quickie are of tandem type. Some earlythree surface aircraft had front elevators (Curtiss/AEA June Bug); modernthree surface aircraft may have both front (canard) and rear elevators (Grumman X-29).
Several technology research and development efforts exist to integrate the functions ofaircraft flight control systems such asailerons, elevators,elevons,flaps andflaperons into wings to perform the aerodynamic purpose with the advantages of less: mass, cost, drag,inertia (for faster, stronger control response), complexity (mechanically simpler, fewer moving parts or surfaces, less maintenance), andradar cross section forstealth. These may be used in manyunmanned aerial vehicles (UAVs) and 6th generationfighter aircraft. Two promising approaches are flexible wings, and fluidics.
In flexible wings, much or all of a wing surface can change shape in flight to deflect air flow. TheX-53 Active Aeroelastic Wing is aNASA effort. TheAdaptive Compliant Wing is a military and commercial effort.[3][4][5]
Influidics, forces in vehicles occur via circulation control, in which larger more complex mechanical parts are replaced by smaller simpler fluidic systems (slots which emit air flows) where larger forces in fluids are diverted by smaller jets or flows of fluid intermittently, to change the direction of vehicles.[6][7][8] In this use, fluidics promises lower mass, costs (up to 50% less), and very lowinertia and response times, and simplicity.
