Pugachev's Cobra



In aerobatics, Pugachev's Cobra (or Pugachev Cobra) is a dramatic and demanding maneuver in which an airplane flying at a moderate speed suddenly raises the nose momentarily to the vertical position and slightly beyond, before dropping it back to normal flight. It uses potent engine thrust to maintain approximately constant altitude through the entire move. Some have speculated that the maneuver may have use in close range combat, although it has never been used in combat. It is an impressive trick to demonstrate an aircraft's pitch control authority, high angle of attack (AOA) stability and engine-versus-inlet compatibility, as well as the pilot's skill. The maneuver is named after the Soviet test pilot Viktor Pugachyov, who performed it in 1989 at the Paris Le Bourget air show. It is claimed that a similar maneuver was performed in the 1960s, by Swedish Air Force pilots in the Saab 35 Draken.

Description
In the case of the Su-27, the pilot initially disengages the angle of attack limiter of the plane, normally set at 26°. This action also disengages the g limiter. After that the pilot pulls back on the stick hard. The aircraft reaches 90–120° angle of attack with a slight gain of altitude and a significant loss of speed. When the elevator is centered, the drag at the rear of the plane causes torque, thus making the aircraft pitch forward. At that time the pilot adds power to compensate for the lift loss. In a properly performed Pugachev's Cobra, the plane maintains almost straight flight throughout the maneuver; the plane does not roll or yaw in either direction. Proper entry speed is significant because, if entering at too low a speed, the pilot might not be able to accomplish the maneuver; entering at too high a speed might result in airframe damage due to the high g-force or for the pilot to lose consciousness.

While Pugachev's Cobra can be executed using only standard aerodynamic controls, it could be achieved more easily with modern thrust vectoring. In the latter case it would be an example of supermaneuverability, specifically poststall maneuvering. The Herbst maneuvering and the helicopter maneuver are other examples of the recent growing use of vectored thrust in 4.5 and fifth-generation jet fighters, manned as well as unmanned.

Potential Employment in combat
The maneuver has never been used in combat. It has been speculated that the maneuver could theoretically be useful when a combatant is being pursued closely by an opponent at a somewhat higher altitude. By executing the cobra, a sufficiently closely pursued aircraft may suddenly slow itself to the point that the pursuer may overshoot it, allowing the previously pursued aircraft to complete the Cobra behind the other. This may give the now-pursuing aircraft an opportunity for firing its weapons, particularly if a proper pointing aspect (facing toward the former pursuer) can be maintained. Maintenance of the proper aspect can be facilitated when the aircraft employs thrust vectoring and/or canard control surfaces.

The disadvantage of performing this maneuver is that it leaves the airplane in a low speed/low energy state, which can leave it vulnerable to attack from opposing aircraft. It can also be countered by maneuvers such as high yo-yo.

Production aircraft

 * Sukhoi Su-27 and variants (Su-30/Su-30MKI/Su-30MKM, Su-33, Su-34, Su-35, Su-37 and Shenyang J-11)
 * Sukhoi PAK FA/Su-50 variant SUKHOI T-50/PAK FA
 * Mikoyan MiG-29M OVT and Mikoyan MiG-35
 * Saab 35 Draken
 * Lockheed F-22 Raptor

Experimental aircraft

 * Rockwell-MBB X-31
 * McDonnell Douglas F/A-18 HARV
 * McDonnell Douglas F-15 STOL/MTD
 * General dynamics F-16 VISTA