Supermaneuverability
However, post-stall analyses have been increasingly used in recent years to advance maneuverability via the use of thrust vectoring engine nozzles.
[2] Russian emphasis on close-range slow-speed supermaneuverability runs counter to Western energy–maneuverability theory, which favors retaining kinetic energy to gain an increasingly better array of maneuvering options the longer an engagement endures.
[3] The USAF abandoned the concept as counter-productive to BVR engagements as the Cobra maneuver leaves the aircraft in a state of near-zero energy, having bled off most of its speed without gaining any compensating altitude in the process.
The speed at which an aircraft is capable of its maximum aerodynamic maneuverability is known as the corner airspeed; at any greater speed the control surfaces cannot operate at maximum effect due to either airframe stresses or induced instability from turbulent airflow over the control surface.
Some aircraft are capable of performing Pugachev's Cobra without the aid of features that normally provide post-stall maneuvering such as thrust vectoring.
Advanced fourth generation fighters such as the Su-27, MiG-29 along with their variants have been documented as capable of performing this maneuver using normal, non-thrust vectoring engines.
The ability of these aircraft to perform this maneuver is based in inherent instability like that of the F-16; the MiG-29 and Su-27 families of jets are designed for desirable post-stall behavior.
[4] The key difference between a pure aerodynamic fighter and a supermaneuverable one is generally found in its post-stall characteristics.
The F-16 has this flaw, due in part to its fly-by-wire controls, which under certain circumstances limit the ability of the pilot to point the nose of the aircraft downward to reduce angle of attack and recover.
This is achieved largely by designing an aircraft that is highly maneuverable, but will not deep stall (thus allowing quick recovery by the pilot) and will recover predictably and favorably (ideally to level flight; more realistically to as shallow a nose-down attitude as possible).
To that design, features are then added that allow the pilot to actively control the aircraft while in the stall, and retain or regain forward level flight in an extremely shallow band of altitude that surpasses the capabilities of pure aerodynamic maneuvering.
In particular, a thrust-to-weight ratio greater than 1:1 is a critical threshold, as it allows the aircraft to maintain and even gain velocity in a nose-up attitude; such a climb is based on sheer engine power, without any lift provided by the wings to counter gravity, and has become crucial to aerobatic maneuvers in the vertical (which are in turn essential to air combat).
Features such as large control surfaces which provide more force with less angular change from neutral which minimizes separation of airflow, lifting body design including the use of strakes, which allow the fuselage of the aircraft to create lift in addition to that of its wings, and low-drag design, particularly reducing drag at the leading edges of the aircraft such as its nose cone, wings and engine intake ducts, are all essential to creating a highly maneuverable aircraft.
Placement below the wings (common on many fighters) exposes the elevators to even greater turbulence from under-wing ordnance.
The original solution to such problems, the T-tail, has been largely discredited as being prone to dangerous "deep stalls".
Canards are not a requirement, and can have disadvantages including reduced pilot visibility, increased mechanical complexity and fragility, and increased radar signature, although radar cross-section can be reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.
It is generally considered impossible, in fact, to perform a true J-turn maneuver without vectored thrust.
