Supermaneuverability - Characteristics - Thrust Vectoring

Thrust Vectoring

Though a high thrust-to-weight ratio and high aerodynamic maneuverability are found on both aerodynamic and supermaneuvering aircraft, the technology most directly linked to supermaneuverability is thrust vectoring, in which the geometry of the exhaust nozzle of a traditional jet engine can be modified to angle the engine's thrust in a direction other than directly to the rear (i.e., upwards or downwards). This applies force to the rear of the aircraft in the opposite direction similar to a conventional control surface, but unlike a control surface the force from the vectored thrust is dependent on current engine thrust, not airspeed; thus thrust vectoring not only augments control surfaces (generally that of the elevators) at speed, but allows the aircraft to retain maximum maneuverability below corner speed and some attitude control below stall speed while in maneuvers. Technology demonstrators such as the X-31, F-16 VISTA and F-15 S/MTD were built to showcase the capabilities of an aircraft using this technology; it has since been incorporated into pre-production and production fighters such as the F-22 Raptor. Eastern Bloc design companies have also introduced this technology into variants of fourth-generation aircraft such as the MiG-29 and Su-27 to produce the MiG-29OVT tech demonstrator and Su-30MKI air superiority fighter respectively, and planned fifth-generation Russian-designed aircraft such as the PAK-FA will use the technology as well. In addition domestic Russian Su-30 fighters will be upgraded with thrust vectoring engines.

Thrust vectoring is most useful while performing maneuvers such as the aerial J-turn, where the nose of the aircraft is pointed upwards (and thus the engine thrust counters gravity as well as providing attitude control). It is generally considered impossible, in fact, to perform a true J-turn maneuver without vectored thrust. Other maneuvers that are considered impossible to perform under control using only aerodynamic maneuvering include the Bell (a 360° loop with negligible altitude change) and the controlled flat spin (360° of yaw around a point of rotation that lies inside the aircraft).