Anti-shock body
Encyclopedia
Leading edge
The leading edge is the part of the wing that first contacts the air; alternatively it is the foremost edge of an airfoil section. The first is an aerodynamic definition, the second a structural one....
or trailing edge
Trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential control surfaces are attached here to redirect the air flow and exert a controlling force by changing its momentum...
of an aircraft's aerodynamic surface to reduce wave drag
Wave drag
In aeronautics, wave drag is a component of the drag on aircraft, blade tips and projectiles moving at transonic and supersonic speeds, due to the presence of shock waves. Wave drag is independent of viscous effects.- Overview :...
at transonic
Transonic
Transonic speed is an aeronautics term referring to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.2, i.e. 600–900 mph...
speeds (Mach
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
0.8–1.2).
Wing trailing edge
Most jet airlinerJet airliner
A jet airliner is an airliner that is powered by jet engines. This term is sometimes contracted to jetliner or jet.In contrast to today's relatively fuel-efficient, turbofan-powered air travel, first generation jet airliner travel was noisy and fuel inefficient...
s have a cruising speed between Mach 0.8 and 0.85. For aircraft operating in the transonic
Transonic
Transonic speed is an aeronautics term referring to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.2, i.e. 600–900 mph...
regime (Mach 0.8-1.2), wave drag can be minimized by having a cross-sectional
Cross section (geometry)
In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...
area which changes smoothly along the length of the aircraft. This is known as the area rule
Area rule
The Whitcomb area rule, also called the transonic area rule, is a design technique used to reduce an aircraft's drag at transonic and supersonic speeds, particularly between Mach 0.75 and 1.2....
, and is the operating principle behind the design of anti-shock bodies. Reducing wave drag improves fuel economy
Fuel efficiency in transportation
The fuel efficiency in transportation ranges from some hundred kilojoule per kilometre for a bicycle to several megajoule for a helicopter.Efficiency can be expressed in terms of consumption per unit distance per vehicle, consumption per unit distance per passenger or consumption per unit distance...
.
On most jet airliners, the mechanisms for deploying the wing flaps
Flap (aircraft)
Flaps are normally hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed an aircraft can be safely flown at and to increase the angle of descent for landing without increasing air speed. They shorten takeoff and landing distances as well as...
are enclosed in fairings, called "flap track fairings", which also serve as anti-shock bodies.
Anti-shock bodies, apparently developed in TsAGI
TsAGI
TsAGI is a transliteration of the Russian abbreviation for Центра́льный аэрогидродинами́ческий институ́т or "Tsentralniy Aerogidrodinamicheskiy Institut", the Central Aerohydrodynamic Institute....
and serving dual purpose as undercarriage bogie's fairings, were first applied to Tupolev Tu-16
Tupolev Tu-16
The Tupolev Tu-16 was a twin-engine jet bomber used by the Soviet Union. It has flown for more than 50 years, and the Chinese license-built Xian H-6 remains in service with the Chinese air force.-Development:...
Badger
Badger
Badgers are short-legged omnivores in the weasel family, Mustelidae. There are nine species of badger, in three subfamilies : Melinae , Mellivorinae , and Taxideinae...
(Type 88), that flew for the first time in April 1952, and were to remain a unique feature of the company's products up to and including the Tu-154.
In the West the theory was developed in the early 1950s by Richard Whitcomb
Richard Whitcomb
Richard T. Whitcomb , was an American aeronautical engineer noted for his significant contributions to the science of aerodynamics....
at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
, and Dietrich Küchemann
Dietrich Küchemann
Dietrich Küchemann CBE FRS FRAeS was a German aerodynamicist who made several important contributions to the advancement of high-speed flight...
at the British Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
. This work led to their appearance on aircraft such as the Convair 990
Convair 990
The Convair 990 Coronado was a narrow-body jet airliner produced by the Convair division of General Dynamics, a "stretched" version of their earlier Convair 880 produced in response to a request from American Airlines. The 990 was lengthened by 10 feet, which increased the number of passengers from...
and the Handley-Page Victor bomber
Handley Page Victor
The Handley Page Victor was a British jet bomber aircraft produced by the Handley Page Aircraft Company during the Cold War. It was the third and final of the V-bombers that provided Britain's nuclear deterrent. The other two V-bombers were the Avro Vulcan and the Vickers Valiant. Some aircraft...
.
Airbus A380
The Airbus A380 is a double-deck, wide-body, four-engine jet airliner manufactured by the European corporation Airbus, a subsidiary of EADS. It is the largest passenger airliner in the world. Due to its size, many airports had to modify and improve facilities to accommodate it...
(Mach 0.85) and the Boeing 777
Boeing 777
The Boeing 777 is a long-range, wide-body twin-engine jet airliner manufactured by Boeing Commercial Airplanes. It is the world's largest twinjet and is commonly referred to as the "Triple Seven". The aircraft has seating for over 300 passengers and has a range from , depending on model...
(Mach 0.84), along with other transonic features like swept wing
Swept wing
A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...
s and supercritical airfoil
Supercritical airfoil
A supercritical airfoil is an airfoil designed, primarily, to delay the onset of wave drag in the transonic speed range. Supercritical airfoils are characterized by their flattened upper surface, highly cambered aft section, and greater leading edge radius compared with traditional airfoil shapes...
s.
Leading edge root
Hawker Sea Hawk
The Hawker Sea Hawk was a British single-seat jet fighter of the Fleet Air Arm , the air branch of the Royal Navy , built by Hawker Aircraft and its sister company, Armstrong Whitworth Aircraft. Although its origins stemmed from earlier Hawker piston-engined fighters, the Sea Hawk became the...
, the first prototypes experienced high tail drag when approaching transonic speeds. To resolve this, an anti-shock body was subsequently fitted to the leading edge of the junction between tail fin and stabiliser.