Twin-tail Aircraft
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A twin tail is a type of
vertical stabilizer 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, sta ...
arrangement found on the
empennage The empennage ( or ), 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.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...
of some
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 ...
. Two vertical stabilizers—often smaller on their own than a single conventional tail would be—are mounted at the outside of the aircraft's
horizontal stabilizer A tailplane, also known as a horizontal stabilizer, 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 gyroplan ...
. This arrangement is also known as an H-tail,Schiff, Barry: ''Flying'', page 15. Golden Press, New York, 1971. Library of Congress 78-103424 as it resembles a capital "H" when viewed from the rear. The twin tail was used on a wide variety of World War II multi-engine designs that saw mass production, especially on the American
B-24 Liberator The Consolidated B-24 Liberator is an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and some initial production aircraft were laid down as export models desi ...
and
B-25 Mitchell The North American B-25 Mitchell is an American medium bomber that was introduced in 1941 and named in honor of Brigadier General William "Billy" Mitchell, a pioneer of U.S. military aviation. Used by many Allied air forces, the B-25 served ...
bombers, the British
Avro Lancaster The Avro Lancaster, commonly known as the Lancaster Bomber, is a British World War II, Second World War heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to ...
and
Handley Page Halifax The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its or ...
heavy bombers, and the Soviet Union's
Petlyakov Pe-2 The Petlyakov Pe-2 ( — nickname «Пешка» (Pawn); NATO reporting name: Buck) was a Soviet Union, Soviet twin-engine dive bomber used during World War II. One of the outstanding tactical attack aircraft of the war,Ethell 1996, p. 152. it ...
attack bomber. It can be easily confused for the similarly named
twin-boom A twin-boom aircraft has two longitudinal auxiliary spars, or “auxiliary booms” , that may contain ancillary components such as fuel tanks and/or provide a supporting structure for other items. Typically, twin tailbooms support the tail ...
(or "double tail") arrangement, which has two separate tail-booms from the same fuselage rather than a single tail with twin stabilizers (a singular "twin tail" vs. two identical tails). One variation on the twin tail is the triple tail, but the twin-boom arrangement can also be considered a variation of the twin tail.


Design

Separating the control surfaces allows for additional
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 ...
area or vertical surface without requiring a massive single tail. On multi-engine
propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...
designs twin fin and rudders operating in the propeller
slipstream A slipstream is a region behind a moving object in which a wake of fluid (typically air or water) is moving at velocities comparable to that of the moving object, relative to the ambient fluid through which the object is moving. The term slips ...
give greater rudder authority and improved control at low
airspeed In aviation, airspeed is the speed of an aircraft relative to the air it is flying through (which itself is usually moving relative to the ground due to wind). In contrast, the ground speed is the speed of an aircraft with respect to the sur ...
s, and when
taxiing Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback (aviation), pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term ...
. A twin tail can also simplify
hangar A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...
requirements, give dorsal gunners enhanced firing area, and in some cases reduce the aircraft's weight. It also affords a degree of redundancy: if one tail is damaged, the other may remain functional. Twin tails with canted fins lean outboard of the turbulence created by the that huge, wide fuselage, improving stability and control especially at high angles of attack. Most often, the twin vertical surfaces are attached to the ends of the horizontal stabilizer, but a few aircraft, like the
Armstrong Whitworth Whitley The Armstrong Whitworth A.W.38 Whitley was a British medium/heavy bomber aircraft of the 1930s. It was one of three twin-engined, front line medium bomber types that were in service with the Royal Air Force (RAF) at the outbreak of the World W ...
,
Mitsubishi G3M The was a Japanese bomber and transport aircraft used by the Imperial Japanese Navy Air Service (IJNAS) during World War II. The Yokosuka L3Y (Allied reporting name "Tina"), was a transport variant of the aircraft manufactured by the Yokosu ...
and
Dornier Do 19 The Dornier Do 19 was a German four-engine heavy bomber that first flew on 28 October 1936. Only one prototype flew, and it was converted to a transport in 1938. The other two were scrapped. The ''Luftwaffe'' lacked an efficient heavy bomber f ...
bombers, had their twin vertical surfaces mounted to the upper surface of the fixed stabilizer instead, at some distance ''inwards'' from the horizontal stabilizer's tips.


Variations

Many canard aircraft designs incorporate twin tails on the tips of the main
wing A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...
. Very occasionally, three or more tails are used, as on the
Breguet Deux-Ponts The Breguet 761/763/765 are a family of 1940s and 1950s French double-deck transport aircraft produced by Breguet Aviation. The aircraft were normally called the Deux-Ponts (Double-Decker) but it was not an official name. Design and development ...
,
Lockheed Constellation The Lockheed Constellation ("Connie") is a propeller-driven, four-engined airliner built by Lockheed Corporation starting in 1943. The Constellation series was the first civil airliner family to enter widespread use equipped with a pressurized cab ...
and
Boeing 314 Clipper The Boeing 314 Clipper was an American long-range flying boat produced by Boeing from 1938 to 1941. One of the largest aircraft of its time, it had the range to cross the Atlantic and Pacific oceans. For its wing, Boeing re-used the design fro ...
. A very unusual design can be seen on the
C-2 Greyhound The Grumman C-2 Greyhound is a twin-engine, high-wing cargo aircraft designed to carry supplies, mail, and passengers to and from List of United States Navy aircraft carriers, aircraft carriers of the United States Navy. Its primary mission is ...
and
E-2 Hawkeye The Northrop Grumman E-2 Hawkeye is an American all-weather, carrier-capable tactical airborne early warning (AEW) aircraft. This twin-turboprop aircraft was designed and developed during the late 1950s and early 1960s by the Grumman Aircraft ...
, which has two additional vertical tails fixed to the horizontal stabilizer between the normal vertical twin-tail surfaces. This arrangement was chosen for the stringent size limitations of carrier-based aircraft. A special case of twin tail is the twin-boom tail or double tail, where the aft airframe consists of two separate fuselages, "tail booms", which each have a rudder but are usually connected by a single horizontal stabilizer. Examples of this construction are the twin-engined
Lockheed P-38 Lightning The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps (USAAC) by the Lockheed Corporation, the P-38 incorporated a distinc ...
;
Northrop P-61 Black Widow The Northrop P-61 Black Widow is a twin-engine United States Army Air Forces fighter aircraft of World War II. It was the first operational U.S. warplane designed specifically as a night fighter. Named for the North American spider '' Latrodec ...
;
Focke-Wulf Fw 189 The Focke-Wulf Fw 189 ''Uhu'' (Owl) is a twin-engine twin-boom tactical Aerial reconnaissance, reconnaissance and Liaison aircraft, army cooperation aircraft designed and produced by the Germany, German aircraft manufacturer Focke-Wulf. It was o ...
; the single jet-engined
de Havilland Vampire The de Havilland DH100 Vampire is a British jet fighter which was developed and manufactured by the de Havilland, de Havilland Aircraft Company. It was the second jet fighter to be operated by the Royal Air Force, RAF, after the Gloster Meteo ...
; cargo-carrying
Fairchild C-119 Flying Boxcar The Fairchild C-119 Flying Boxcar (Navy and Marine Corps designation R4Q) is an American military transport aircraft developed from the World War II-era Fairchild C-82 Packet, designed to carry cargo, personnel, Litter (rescue basket), litte ...
and the little known
Transavia PL-12 Airtruk The Transavia PL-12 Airtruk is a single-engine agricultural aircraft designed and built by the Transavia Corporation in Australia. The Airtruk is a shoulder-wing strut braced sesquiplane of all-metal construction, with the cockpit mounted above a ...
.


Notable twin-tail aircraft

Significant aircraft with twin tails include the
Consolidated B-24 Liberator The Consolidated B-24 Liberator is an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and some initial production aircraft were laid down as export models desi ...
,
Handley Page Halifax The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its or ...
,
Avro Lancaster The Avro Lancaster, commonly known as the Lancaster Bomber, is a British World War II, Second World War heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to ...
, and P-38 Lightning. The arrangement is not limited to
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
-era aircraft, however. Many
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 ...
, like the
Grumman F-14 Tomcat The Grumman F-14 Tomcat is an American carrier-capable supersonic aircraft, supersonic, twinjet, twin-engine, Tandem#Aviation, tandem two-seat, twin-tail, all-weather-capable variable-sweep wing fighter aircraft. The Tomcat was developed for t ...
,
McDonnell Douglas F-15 Eagle The McDonnell Douglas F-15 Eagle is an American twin-engine, all-weather fighter aircraft designed by McDonnell Douglas (now part of Boeing). Following reviews of proposals, the United States Air Force (USAF) selected McDonnell Douglas's desi ...
,
Sukhoi Su-27 The Sukhoi Su-27 (; NATO reporting name: Flanker) is a Soviet Union, Soviet-origin twinjet, twin-engine supersonic Supermaneuverability, supermaneuverable fighter aircraft designed by Sukhoi. It was intended as a direct competitor for the lar ...
,
MiG-29 The Mikoyan MiG-29 (; NATO reporting name: Fulcrum) is a twinjet, twin-engine fighter aircraft designed in the Soviet Union. Developed by the Mikoyan design bureau as an air superiority fighter during the 1970s, the MiG-29, along with the large ...
, and
Fairchild Republic A-10 Thunderbolt II The Fairchild Republic A-10 , also infamously known under the nickname , is a single-seat, twin-turbofan, straight-wing, subsonic attack aircraft developed by Fairchild Republic for the United States Air Force (USAF). In service since 19 ...
, make use of twin tail configurations, as do civilian and cargo designs like the
Antonov An-14 The Antonov An-14 Pchelka or Pchyolka, Bdzhilka (, "Little Bee", NATO reporting name: Clod)Taylor 1976, pp. 404–405. is a Soviet utility aircraft which was first flown on 15 March 1958.Stroud 1968, p. 65. It was a twin-engined light STOL ut ...
,
Antonov An-22 The Antonov An-22 "Antei" (; ; NATO reporting name: "Cock") is a heavy military transport aircraft designed by the Antonov Design Bureau in the Soviet Union. Powered by four turboprop engines, each driving a pair of contra-rotating propellers, ...
,
Antonov An-28 The Antonov An-28 (NATO reporting name Cash) is a twin-engined light turboprop transport aircraft, developed from the Antonov An-14M. It was the winner of a competition against the Beriev Be-30, for use by Aeroflot as a short-range airliner. It ...
,
Antonov An-38 The Antonov An-38 is a stretched and upgraded version of Antonov's earlier An-28. It is a twin-engined turboprop transport aircraft, designed by the Antonov Design Bureau in Kyiv, Ukraine. Production is in Novosibirsk, Russia, but some crucial ...
,
Antonov An-225 The Antonov An-225 Mriya (; NATO reporting name: Cossack) was a large strategic airlift cargo aircraft designed and produced by the Antonov Design Bureau in the Soviet Union. It was originally developed during the 1980s as an enlarged derivat ...
,
Beechcraft 18 The Beechcraft Model 18 (or "Twin Beech", as it is also known) is a 6- to 11-seat, twin-engined, low-wing, tailwheel light aircraft manufactured by the Beech Aircraft Corporation of Wichita, Kansas. Continuously produced from 1937 to Novembe ...
,
Beriev Be-12 The Beriev Be-12 ''Chayka'' (, NATO reporting name: Mail) is a Soviet turboprop-powered amphibious aircraft designed in the 1950s for anti-submarine and maritime patrol duties. Design and development The Beriev Be-12 was a successor to the B ...
,
ERCO Ercoupe The ERCO Ercoupe is an American low-wing monoplane aircraft that was first flown in 1937. It was originally manufactured by the Engineering and Research Corporation (ERCO) shortly before World War II; several other manufacturers continued its ...
,
Short 330 The Short 330 (also SD3-30) is a small turboprop transport aircraft produced by Short Brothers. It seats up to 30 people and was relatively inexpensive and had low maintenance costs at the time of its introduction in 1976. The 330 was based on ...
,
Rutan Long-EZ The Rutan Model 61 Long-EZ is a tandem 2-seater homebuilt aircraft designed by Burt Rutan's Scaled Composites. The Long-EZ has a canard layout, a swept wing with wingtip rudders, and a pusher engine and propeller. The tricycle landing gear ha ...
and
SpaceShipOne SpaceShipOne is an experimental air launch, air-launched rocket-powered aircraft with sub-orbital spaceflight capability at speeds of up to / using a hybrid rocket motor. The design features a unique "Feathering (reentry), feathering" atmosph ...
. The
V-22 Osprey The Bell Boeing V-22 Osprey is an American multi-use, tiltrotor military transport aircraft, military transport and cargo aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed ...
uses a twin tail arrangement.


See also

*
Cruciform tail The cruciform tail is an aircraft empennage configuration which, when viewed from the aircraft's front or rear, looks much like a cross. The usual arrangement is to have the tailplane, horizontal stabilizer intersect the vertical tail somewhere ...
*
Pelikan tail The Pelikan tail is an experimental tail design for fighter jets. It was originally conceived by Ralph Pelikan, who was hired by McDonnell Aircraft, later worked for McDonnell Douglas after the merger of McDonnell with Douglas and, after another ...
*
T-tail A T-tail is an empennage wikt:configuration, configuration in which the tailplane of an aircraft is mounted to the top of the vertical stabilizer, fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs fr ...
*
V-tail The V-tail or ''vee-tail'' (sometimes called a butterfly tail or Rudlicki's V-tailGudmundsson S. (2013). "General Aviation Aircraft Design: Applied Methods and Procedures" (Reprint). Butterworth-Heinemann. p. 489. , 9780123973290) of an aircraf ...


References

{{DEFAULTSORT:Twin Tail Aircraft tail configurations