
Elevators are
flight control surfaces, usually at the rear of an
aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
, which control the aircraft's
pitch, and therefore the
angle of attack and the lift of the wing. The elevators are usually hinged to the
tailplane or horizontal
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,
horizontal stabilizer usually creates a ''downward'' force which balances the nose down
moment created by the wing lift force, which typically applies at a point (the wing center of lift) situated
aft of the airplane's
center of gravity. The effects of
drag and changing the engine
thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...
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. 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
trim tab is present at the rear of the elevator, which the pilot can adjust to eliminate forces on the
control column at the desired attitude and airspeed.
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
canard (the
French word for
duck) or a
tandem wing. The
Wright Brothers
The Wright brothers, Orville Wright (August 19, 1871 – January 30, 1948) and Wilbur Wright (April 16, 1867 – May 30, 1912), were American aviation List of aviation pioneers, pioneers generally credited with inventing, building, and flyin ...
' early aircraft were of the canard type;
Mignet Pou-du-Ciel and
Rutan Quickie are of tandem type. Some early
three surface aircraft had front elevators (
Curtiss/AEA June Bug); modern
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
aircraft flight control system
A conventional Fixed-wing aircraft, fixed-wing aircraft flight control system (AFCS) consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's di ...
s such as
ailerons, elevators,
elevons,
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 vehicle
An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...
s (UAVs) and 6th generation
fighter aircraft
Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...
. 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
X-53 Active Aeroelastic Wing is a
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
effort. The
Adaptive Compliant Wing is a military and commercial effort.
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.
In this use, fluidics promises lower mass, costs (up to 50% less), and very low
inertia and response times, and simplicity.
Gallery
Image:elevator.curriewot.arp.750pix.jpg, A drooped ''elevator'', nearly touching the grass, on the horizontal stabilizer of this Currie Wot biplane
File:Tail of a conventional aircraft.svg, The tail of an Airbus A380, showing the ''elevators'' at the rear of the horizontal stabilizer
Image:Airbus-Höhenruder.jpg, Pre-installed elevators for a small Airbus
Airbus SE ( ; ; ; ) is a Pan-European aerospace corporation. The company's primary business is the design and manufacturing of commercial aircraft but it also has separate Airbus Defence and Space, defence and space and Airbus Helicopters, he ...
. 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
*
Rudder
A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...
*
Aileron
References
External links
Aircraft Pitch Motion(elevator function explanation,
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
website)
{{DEFAULTSORT:Elevator (Aircraft)
Aircraft controls
Attitude control