In
aviationAviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
, a
stabilizer provides stability when the
aircraftAn aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
is flying straight, and the airfoil of the horizontal stabilizer balances the forces acting on the aircraft.
While the vertical stabilizer and rudder are always placed on the
empennageThe empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...
(the rear of the aircraft or tail), or at the ends of aft-swept wings, the horizontal surfaces can be placed on the front or the rear. When placed at the rear, the horizontal stabilizer is called a
tailplaneA tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...
. When placed at the front, it is called a
canardIn aeronautics, canard is an airframe configuration of fixed-wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", while the latter is the main wing...
. A combined vertical-horizontal stabilizer is used in the
V-tailIn aircraft, a V-tail is an unconventional arrangement of the tail control surfaces that replaces the traditional fin and horizontal surfaces with two surfaces set in a V-shaped configuration when viewed from the front or rear of the aircraft...
configuration.
Tailplane
The
horizontal stabilizer or
tailplaneA tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...
is a fixed or adjustable surface from which an
elevatorElevators are flight 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. In simplified terms, they make the aircraft nose-up or nose-down...
may be hinged. In some aircraft models (mostly jets), the entire horizontal stabilizer rotates and functions as an elevator. This combination is often called a
stabilatorA stabilator is an aircraft control surface that combines the functions of an elevator and a horizontal stabilizer...
(see
Cessna 177The Cessna 177 Cardinal is a light, high-wing general aviation aircraft that was intended to replace Cessna's 172 Skyhawk. First announced in 1967, it was produced from 1968 to 1978.-Development:...
or
Piper CherokeeThe Piper PA-28 Cherokee is a family of light aircraft designed for flight training, air taxi, and personal use. It is built by Piper Aircraft....
for light aircraft applications).
Aircraft with an adjustable stabilizer have the stabilizer hinged so that its setting (
angle of incidenceAngle of incidence is a measure of deviation of something from "straight on", for example:* in the approach of a ray to a surface, or* the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the fuselage.-Optics:In geometric...
) can be altered in flight (see
McDonnell Douglas DC-9The McDonnell Douglas DC-9 is a twin-engine, single-aisle jet airliner. It was first manufactured in 1965 with its maiden flight later that year. The DC-9 was designed for frequent, short flights. The final DC-9 was delivered in October 1982.The DC-9 was followed in subsequent modified forms by...
for an airliner application; see
Cessna 180The Cessna 180 is a four- or six-seat, fixed conventional gear general aviation airplane which was produced between 1953 and 1981. Though the design is no longer in production, many of these aircraft are still in use as personal aircraft and in utility roles such as bush...
for a light aircraft application). The resulting stabilized speed is known as the
trim speed, and the trim is used to set the desired speed without having to hold the elevator out of its trimmed or faired (trail) position. In aircraft with truly fixed stabilators, a trim tab on the trailing edge of the elevator is used to alter the aircraft's trim speed (see
Douglas DC-3The Douglas DC-3 is an American fixed-wing propeller-driven aircraft whose speed and range revolutionized air transport in the 1930s and 1940s. Its lasting impact on the airline industry and World War II makes it one of the most significant transport aircraft ever made...
for an airliner application; see
Cessna 172The Cessna 172 Skyhawk is a four-seat, single-engine, high-wing fixed-wing aircraft. First flown in 1955 and still in production, more Cessna 172s have been built than any other aircraft.-Design and development:...
for a light aircraft application). The
F-86 SabreThe North American F-86 Sabre was a transonic jet fighter aircraft. Produced by North American Aviation, the Sabre is best known as America's first swept wing fighter which could counter the similarly-winged Soviet MiG-15 in high speed dogfights over the skies of the Korean War...
first used a fixed stabilizer and elevators with a trim tab, but later versions used a stabilator.
Canard
When placed on the front, the aircraft is called a
canardIn aeronautics, canard is an airframe configuration of fixed-wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", while the latter is the main wing...
(see
Beechcraft StarshipThe Beechcraft Starship is a twin-turboprop six- to eight-passenger pressurized business aircraft produced by Beech Aircraft Corporation .-Development:...
for a large aircraft and
Rutan Long-EZ-See also:-External links:****...
for a small aircraft with this configuration). The Italian-designed Piaggio P.180 Avanti uses a rear-mounted stabilizer/elevator and a forward stabilizer (fixed, with no control surfaces); this combination arrangement is probably unique in present-day aircraft, although some early airplanes tried such arrangements.
Vertical stabilizer
The
vertical stabilizerThe vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...
or
finA fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
is fixed to the aircraft and supports the
rudderA rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
. The fin nearly always employs a small
filletIn mechanical engineering, a fillet is a concave easing of an interior corner of a part design. A rounding of an exterior corner is called a "round" or a "chamfer".-Applications:...
at its forward base, called a dorsal fin, which prevents a phenomenon called
rudder lock. Rudder lock is where the force on a fully deflected rudder (in a steady
sideslipA slip is an aerodynamic state where an aircraft is moving somewhat sideways as well as forward relative to the oncoming airflow. In other words, for a conventional aircraft, the nose will not be pointing directly into the relative wind .A slip is also a piloting maneuver where the pilot...
) suddenly reverses as the rudder reaches its maximum travel. The phenomenon is usually corrected by addition of a dorsal fin.
V-tail
For aircraft with a
V-tailIn aircraft, a V-tail is an unconventional arrangement of the tail control surfaces that replaces the traditional fin and horizontal surfaces with two surfaces set in a V-shaped configuration when viewed from the front or rear of the aircraft...
, each stabilizer/fin will support a "ruddervator", combining the functions of both the rudder and the elevator.
See also
- Aircraft flight control systems
A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight...
- Elevator (aircraft)
Elevators are flight 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. In simplified terms, they make the aircraft nose-up or nose-down...
- Flight control surfaces
- T-tail
thumb|right|Grob motor gliderA T-tail is an aircraft tail stabilizer configuration in which the horizontal surfaces are mounted to the top of the vertical stabilizer. Traditionally, the horizontal control surfaces are mounted to the fuselage at the base of the vertical stabilizer...
- American Airlines Flight 587
American Airlines Flight 587, an Airbus A300, crashed into the Belle Harbor neighborhood of Queens, a borough of New York City, New York, shortly after takeoff from John F. Kennedy International Airport on November 12, 2001. This is the second deadliest U.S...
, crashed after losing its stabilizers.
- Japan Airlines Flight 123
Japan Airlines Flight 123 was a Japan Airlines domestic flight from Tokyo International Airport to Osaka International Airport on August 12, 1985. The Boeing 747-146SR that made this route, registered , suffered mechanical failures 12 minutes into the flight and 32 minutes later crashed into two...
, stabilizers were blown off in an explosive decompression.
- Alaska Airlines Flight 261
Alaska Airlines Flight 261, a McDonnell Douglas MD-83 aircraft, experienced a fatal accident on January 31, 2000 at the Pacific Ocean about 2.7 miles north of Anacapa Island, California. The two pilots, three cabin crewmembers, and 83 passengers on board were killed and the aircraft was destroyed...
, crashed due to the failure of its stabilizer trim jackscrew.
- Kälvesta air disaster
External links