Thrust Vectoring

Thrust vectoring can be decribed as the ability of an aircraft to direct thrust, produced by its main engine(s), in a direction that is different than parallel to the aircraft's longitudinal axis. Originally, the technique of thrust vectoring was envisaged to provide upward vertical thrust as a means to give aircraft Vertical Take-Off and Landing or Short Take-Off and Landing ability. Later it was realized that using vectored thrust in combat situations could enable aircraft to perform various maneuvers not available to conventional-engined planes. Basically this means that aircraft that do not utilize thrust vectoring have to rely on aerodynamic control surface deflection, while aircraft that actually do use thrust vectoring depend on control surface operation to a lesser extent.

Most aircraft currently equipped with thrust vectoring ability use turbofans with rotating nozzles or vanes in order to deflect the exhaust stream. This method can successfully deflect exhaust streams through as much as 90 degrees, relative to the aircraft centerline. However, a weight penalty has to be accounted for since the engine must be sized for vertical lift rather than normal flight. Afterburning is also difficult to incorporate and is mostly impractible for take-off and landing as the hot exhaust can damage runway surfaces. At the same time afterburning is necessary to reach supersonic flight speeds.

Thrust Vectored Aircraft

One of the best known examples of thrust vectoring in an engine is the Rolls-Royce Pegasus engine installed in the Hawker Siddeley Harrier. Although thrust vectoring with the Harrier, also called "Vectoring In Forward Flight" or VIFFing, is actively discouraged by the Royal Air Force and Royal Navy, it is encouraged and actively practiced by the United States Marine Corps. This technique has been used in various experimental and development planes, some with vectored thrust in directions other than downwards.

The Lockheed Martin F-35 Lightning, currently in its development stage, incorporates a conventional afterburning turbofan which facilitates supersonic operation, together with a vertically mounted, low pressure shaft-driven remote fan, driven through a clutch during landing from the engine. The exhaust from this fan is deflected by a thrust vectoring nozzle to provide the appropriate combination of lift and propulsive thrust during transition.

The Sukhoi Su-30 MKI, powered by two AI-31FP afterburning turbofans, is an aircraft that employs 2D thrust vectoring, which makes it highly maneuverable. The Su-30 is capable of near-zero airspeed at high angles of attack and dynamic aerobatics in negative speeds up to 200 km/h. The thrust vectoring nozzles of the MKI are mounted 32 degrees outward to the longitudinal engine axis and can be deflected approximately 15 degrees in the vertical plane. This produces the cork-screw effect and enhances the turning capability of the aircraft.

List of Thrust Vectored Aircraft

VTOL ability

  • Boeing V-22 Osprey
  • Boeing X-32
  • Dornier Do 31
  • Harrier Jump Jet
    - BAE Systems/Boeing Harrier II
    - Boeing/BAe Systems AV-8B Harrier II
    - British Aerospace Sea Harrier
    - Hawker Siddeley Harrier
  • Lockheed Martin F-35 Lightning II (B model)
  • Moller Skycar

Two dimension vectoring (pitch)

  • Boeing X-32
  • Lockheed Martin F-22 Raptor
  • McDonnell Douglas F-15S/MTD
  • McDonnell Douglas X-36
  • Sukhoi Su-30MKI
  • Sukhoi Su-37
  • Sukhoi Su-47

Three dimension vectoring

  • Lockheed F-16 MATV
  • McDonnell Douglas F-15 ACTIVE
  • McDonnell Douglas F-18 HARV
  • Mikoyan MiG-29OVT
  • Mikoyan Project 1.44
  • Mitsubishi ATD-X
  • Rockwell-MBB X-31
  • X-44 MANTA
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