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The empennage of a Boeing 747-200 Aircraft tail.JPG
The empennage of a Boeing 747-200

The empennage ( /ˌɑːmpɪˈnɑːʒ/ or /ˈɛmpɪnɪ/ ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow. [1] [2] [3] The term derives from the French language verb empenner which means "to feather an arrow". [4] Most aircraft feature an empennage incorporating vertical and horizontal stabilising surfaces which stabilise the flight dynamics of yaw and pitch, [1] [2] as well as housing control surfaces.


In spite of effective control surfaces, many early aircraft that lacked a stabilising empennage were virtually unflyable. Even so-called "tailless aircraft" usually have a tail fin (usually a vertical stabiliser). Heavier-than-air aircraft without any kind of empennage (such as the Northrop B-2) are rare, and generally use specially shaped airfoils whose trailing edge provide pitch stability, and rearwards swept wings, often with dihedral to provide the necessary yaw stability. In some aircraft with swept wings, the airfoil section or angle of incidence may change radically towards the tip.


The major components of an airplane's empennage. Empennage components.png
The major components of an airplane's empennage.

Structurally, the empennage consists of the entire tail assembly, including the tailfin, the tailplane and the part of the fuselage to which these are attached. [1] [2] On an airliner this would be all the flying and control surfaces behind the rear pressure bulkhead.

Yaw, pitch, and roll in an aircraft. Flight dynamics with text ortho.svg
Yaw, pitch, and roll in an aircraft.

The front (usually fixed) section of the tailplane is called the horizontal stabiliser and is used to provide pitch stability. The rear section of the tailplane is called the elevator, and is a movable aerofoil that controls changes in pitch, the up-and-down motion of the aircraft's nose. In some aircraft the horizontal stabilizer and elevator are one unit, and to control pitch the entire unit moves as one. This is known as a stabilator or full-flying stabiliser. [1] [2]

The vertical tail structure has a fixed front section called the vertical stabiliser , used to control yaw, which is movement of the fuselage right to left motion of the nose of the aircraft. The rear section of the vertical fin is the rudder , a movable aerofoil that is used to turn the aircraft's nose right or left. When used in combination with the ailerons, the result is a banking turn, a coordinated turn, the essential feature of aircraft movement. [1] [2]

Some aircraft are fitted with a tail assembly that is hinged to pivot in two axes forward of the fin and stabiliser, in an arrangement referred to as a movable tail. The entire empennage is rotated vertically to actuate the horizontal stabiliser, and sideways to actuate the fin. [5]

The aircraft's cockpit voice recorder, flight data recorder and emergency locator transmitter (ELT) are often located in the empennage, because the aft of the aircraft provides better protection for these in most aircraft crashes.


In some aircraft trim devices are provided to eliminate the need for the pilot to maintain constant pressure on the elevator or rudder controls. [5] [6]

The trim device may be:

Multi-engined aircraft often have trim tabs on the rudder to reduce the pilot effort required to keep the aircraft straight in situations of asymmetrical thrust, such as single engine operations. [7]

Tail configurations

Aircraft empennage designs may be classified broadly according to the fin and tailplane configurations.

The overall shapes of individual tail surfaces (tailplane planforms, fin profiles) are similar to wing planforms.


The tailplane comprises the tail-mounted fixed horizontal stabiliser and movable elevator. Besides its planform, it is characterised by:

Some locations have been given special names:

Tail fuselage mounted.svg
Fuselage mounted
Tail cruciform.svg
Tail T.svg
Tail plane flying.svg
Flying tailplane


The fin comprises the fixed vertical stabiliser and rudder. Besides its profile, it is characterised by:

Twin fins may be mounted at various points:

Tail twin tailplane mounted.svg
Tailplane mounted
Tail twin boom.svg
Twin tail boom
Tail twin wing mounted.svg
Wing mounted

Unusual fin configurations include:

Tail fin triple.svg
Triple fins
Tail fin ventral.svg
Ventral fin

V, Y and X tails

An alternative to the fin-and-tailplane approach is provided by the V-tail and X-tail designs. Here, the tail surfaces are set at diagonal angles, with each surface contributing to both pitch and yaw. The control surfaces, sometimes called ruddervators, act differentially to provide yaw control (in place of the rudder) and act together to provide pitch control (in place of the elevator). [1]

Tail V.svg
Tail inverted V.svg
Inverted V-tail
Tail X.svg

Outboard tail

SpaceShipOne at the US National Air and Space Museum Spaceship One at Smithsonian.jpg
SpaceShipOne at the US National Air and Space Museum

An outboard tail is split in two, with each half mounted on a short boom just behind and outboard of each wing tip. It comprises outboard horizontal stabilizers (OHS) and may or may not include additional boom-mounted vertical stabilizers (fins). In this position, the tail surfaces interact constructively with the wingtip vortices and, with careful design, can significantly reduce drag to improve efficiency, without adding unduly to the structural loads on the wing. [11]

The configuration was first developed during World War II by Richard Vogt and George Haag at Blohm & Voss. The Skoda-Kauba SL6 tested the proposed control system in 1944 and, following several design proposals, an order was received for the Blohm & Voss P 215 just weeks before the war ended. [12] [13] The outboard tail reappeared on the Scaled Composites SpaceShipOne in 2003 and SpaceShipTwo in 2010. [14]

Tailless aircraft

The DH108 Swallow DH 108 Swallow tg283.jpg
The DH108 Swallow

A tailless aircraft (often tail-less) traditionally has all its horizontal control surfaces on its main wing surface. It has no horizontal stabiliser - either tailplane or canard foreplane (nor does it have a second wing in tandem arrangement). A 'tailless' type usually still has a vertical stabilising fin (vertical stabiliser) and control surface (rudder). However, NASA adopted the 'tailless' description for the novel X-36 research aircraft which has a canard foreplane but no vertical fin.[ citation needed ]

The most successful tailless configuration has been the tailless delta, especially for combat aircraft.[ citation needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Tailplane</span> Small lifting surface of a fixed-wing aircraft

A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplanes. Not all fixed-wing aircraft have tailplanes. Canards, tailless and flying wing aircraft have no separate tailplane, while in V-tail aircraft the vertical stabiliser, rudder, and the tail-plane and elevator are combined to form two diagonal surfaces in a V layout.

<span class="mw-page-title-main">T-tail</span> Aircraft empennage configuration

A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs from the standard configuration in which the tailplane is mounted to the fuselage at the base of the fin.

<span class="mw-page-title-main">Flight control surfaces</span> Surface that allows a pilot to adjust and control an aircrafts flight attitude

Aircraft flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude.

<span class="mw-page-title-main">V-tail</span> Type of aircraft tail

The V-tail or Vee-tail of an aircraft 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. It is not widely used in aircraft design. The aft edge of each twin surface is a hinged control surface called a ruddervator, which combines the functions of both a rudder and elevator.

<span class="mw-page-title-main">Elevator (aeronautics)</span> Aircraft flight control surface

Elevators are flight control surfaces, usually at the rear of an aircraft, 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 or integrated into a rear "all-moving tailplane", also called a slab elevator or stabilator.

<span class="mw-page-title-main">Stabilator</span>

A stabilator is a fully movable aircraft horizontal stabilizer. It serves the usual functions of longitudinal stability, control and stick force requirements otherwise performed by the separate parts of a conventional horizontal stabilizer and elevator. Apart from reduced drag, particularly at high Mach numbers, it is a useful device for changing the aircraft balance within wide limits, and for reducing stick forces.

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<span class="mw-page-title-main">Vertical stabilizer</span> Aircraft component

A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, stability and trim in yaw. It is part of the aircraft empennage, specifically of its stabilizers.

<span class="mw-page-title-main">Mach tuck</span> Aerodynamic effect

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<span class="mw-page-title-main">Stabilizer (aeronautics)</span> Aircraft component

An aircraft stabilizer is an aerodynamic surface, typically including one or more movable control surfaces, that provides longitudinal (pitch) and/or directional (yaw) stability and control. A stabilizer can feature a fixed or adjustable structure on which any movable control surfaces are hinged, or it can itself be a fully movable surface such as a stabilator. Depending on the context, "stabilizer" may sometimes describe only the front part of the overall surface.

<span class="mw-page-title-main">Trailing edge</span> Rear edge of an aerodynamic surface

The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets. Essential flight control surfaces are attached here to control the direction of the departing air flow, and exert a controlling force on the aircraft. Such control surfaces include ailerons on the wings for roll control, elevators on the tailplane controlling pitch, and the rudder on the fin controlling yaw. Elevators and ailerons may be combined as elevons on tailless aircraft.

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Pterodactyl was the name given to a series of experimental tailless aircraft designs developed by G. T. R. Hill in the 1920s and early 1930s. Named after the genus Pterodactylus, a well-known type of Pterosaur commonly known as the pterodactyl, all but the first were produced by Westland Aircraft Ltd after Hill joined them.

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In aeronautics, a tailless aircraft is an aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin, and/or vertical rudder.

<span class="mw-page-title-main">Wing configuration</span> Describes the general shape and layout of an aircraft wing

The wing configuration of a fixed-wing aircraft is its arrangement of lifting and related surfaces.

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<span class="mw-page-title-main">Outboard tail</span>

An outboard tail is a type of aircraft tail or empennage which is split in two, with each half mounted on a short boom just behind and outboard of each wing tip. It comprises outboard horizontal stabilizers (OHS) and may or may not include additional boom-mounted vertical stabilizers (fins). OHS designs are sometimes described as a form of tailless aircraft.

The Blohm & Voss P215 was an advanced jet night fighter project by Blohm & Voss during the Second World War. With a crew of three and twin jet engines, it featured a tailless swept-wing layout and heavy armament. An order for three prototypes was received just weeks before the war ended.


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