Elevator (aeronautics)

Source: Wikipedia, the free encyclopedia.
For other uses, see Elevator (disambiguation).
Elevators' effect on pitch
Elevator and pitch trim tab of a light aircraft

Elevators are

stabilizer. They may be the only pitch control surface present, and are sometimes located at the front of the aircraft (early airplanes and canards) or integrated into a rear "all-moving tailplane", also called a slab elevator or stabilator
.

Elevator control effectiveness

The elevator is a usable up and down system that controls the plane,

center of gravity. The effects of drag and changing the engine thrust
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:

  • an increased downward force, produced by up elevator, forces the tail down and the nose up. At constant speed, the wing's increased angle of attack causes a greater lift to be produced by the wing, accelerating the aircraft upwards. The drag and power demand also increase;
  • a decreased downward force at the tail, produced by down elevator, causes the tail to rise and the nose to lower. At constant speed, the decrease in angle of attack reduces the lift, accelerating the aircraft downwards.

On many low-speed aircraft, a

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 combine ailerons and elevators –and their respective control inputs– into one control surface called an elevon
.

Elevators' location

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 a

three surface aircraft may have both front (canard) and rear elevators (Grumman X-29
).

Research

Several technology research and development efforts exist to integrate the functions of

flaps and flaperons 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), and radar cross section for stealth. These may be used in many unmanned aerial vehicles (UAVs) and 6th generation fighter 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. The

Adaptive Compliant Wing is a military and commercial effort.[3][4][5]

In fluidics, 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 low inertia and response times, and simplicity.

Gallery

  • A drooped elevator, nearly touching the grass, on the horizontal stabilizer of this Currie Wot biplane
    A drooped elevator, nearly touching the grass, on the horizontal stabilizer of this Currie Wot biplane
  • The tail of an Airbus A380, showing the elevators at the rear of the horizontal stabilizer
    The tail of an Airbus A380, showing the elevators at the rear of the horizontal
    stabilizer
  • Pre-installed elevators for a small Airbus. The elevator is the silver surface on the right hand side of the picture, immediately below the red pipes on the factory wall.
    Pre-installed elevators for a small Airbus. The elevator is the silver surface on the right hand side of the picture, immediately below the red pipes on the factory wall.

See also

References

  1. ISBN 978-0-470-53975-0
    .
  2. ^ "3 - Basic Flight Maneuvers". Airplane Flying Handbook. U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration. 2004. FAA-8083-3A. Archived from the original on 2011-06-30.
  3. ^ Scott, William B. (27 November 2006), "Morphing Wings", Aviation Week & Space Technology
  4. ^ "FlexSys Inc.: Aerospace". Archived from the original on 16 June 2011. Retrieved 26 April 2011.
  5. ^ Kota, Sridhar; Osborn, Russell; Ervin, Gregory; Maric, Dragan; Flick, Peter; Paul, Donald. "Mission Adaptive Compliant Wing – Design, Fabrication and Flight Test" (PDF). Ann Arbor, MI; Dayton, OH, U.S.A.: FlexSys Inc., Air Force Research Laboratory. Archived from the original (PDF) on 22 March 2012. Retrieved 26 April 2011.
  6. S2CID 56205932. Archived from the original
    on 2018-05-17.
  7. ^ "Showcase UAV Demonstrates Flapless Flight". BAE Systems. 2010. Archived from the original on 2011-07-07. Retrieved 2010-12-22.
  8. ^ "Demon UAV jets into history by flying without flaps". Metro.co.uk. London: Associated Newspapers Limited. 28 September 2010.

External links

Wikimedia Commons has media related to Elevators (aircraft).
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