Pugachev's Cobra

[Nawaba]

In aerobatics, Pugachev's Cobra (or Pugachev Cobra) is a dramatic and demanding manoeuvre 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.[1] The manoeuvre supposedly has some use in close range combat,[2] and 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 manoeuvre is named after the Soviet test pilot Viktor Pugachev, who first performed the manoeuvre publicly in 1989 at the ParisLe Bourgetair show.

Pugachev's Cobra - Wikipedia, the free encyclopedia

Sources claim thrust vectoring makes the effort redundant and a chore.

Please discuss

@Oscar @Manticore

 

[gambit]

There is nothing to discuss.

John Boyd - USAF, The Fighter Pilot Who Changed the Art of Air Warfare

Boyd was famous for a maneuver he called "flat-plating the bird." He would be in the defensive position with a challenger tight on his tail, both pulling heavy Gs, when he would suddenly pull the stick full aft, brace his elbows on either side of the cockpit, so the stick would not move laterally, and stomp the rudder. It was as if a manhole cover were sailing through the air and then suddenly flipped 90 degrees. The underside of the fuselage, wings, and horizontal stabilizer became a speed brake that slowed the Hun from 400 knots to 150 knots in seconds. The pursuing pilot was thrown forward and now Boyd was on his tail radioing "Guns. Guns. Guns."

Boyd did it before Pugachev and he did it with an older aircraft.

 

[Nawaba]

There is nothing to discuss.

John Boyd - USAF, The Fighter Pilot Who Changed the Art of Air Warfare

Boyd did it before Pugachev and he did it with an older aircraft.

What are your thoughts about thrust vectoring? Does TVC make such maneuvers obsolete or easier for less experienced pilots?

 

[Pulsar]

It's a useless manoeuvre! It just looks sexy during air shows and on You Tube!

These are the words of a chief test pilot I spoke to.

 

[Ray_of_Hope]

Pugachev Cobra manoeuvre has no dog fight implications.Its just a stunt for people in air shows to enjoy.Am i right @Oscar

 

[gambit]

What are your thoughts about thrust vectoring? Does TVC make such maneuvers obsolete or easier for less experienced pilots?

What Boyd did may have worked in less technologically advanced era but would not work today. Against an F-16 that have much greater maneuverability and shorter response time, Boyd would be quite virtually 'dead' with that trick.

How Things Work: Thrust Vectoring | Flight Today | Air & Space Magazine

One common misconception about thrust vectoring involves the flashy cobra maneuver, also known as Pugachev’s cobra, after Russian pilot Viktor Pugachev, who first wowed crowds with it in a Sukhoi Su-27 at the 1989 Paris Air Show. The maneuver is not an example of thrust vectoring. If the pilot is skilled enough, he can do the cobra in nearly any type of U.S. jet fighter. In essence, the pilot abruptly pulls the control yoke full aft while flying around 300 knots—about 345 mph—and thus pitches the nose up dramatically so the airplane is nearly standing on its tail. Just as abruptly, the pilot pushes the stick forward, dropping the nose back down. When the maneuver is flown correctly, with little change in altitude, the effect is like the striking of a cobra’s head.

Thrust vectoring does have its use, but only in very narrow circumstances. For that airshow, if Pugachev used the -27's TVC, and let us assume he did, it was to recover, not to initiate the pitch (nose) up action. In other words, he probably used the -27's TVC to prevent the jet from flipping completely back and most likely leaving controlled flight.

In modern software dominated flight controls system, surface deflections are governed by complex calculations based upon airspeed, altitude, command (pilot), rate of change, degree of change, and feedback. All of these are continuously monitored and adjust in real time, as in pico-seconds. So when I already have forward momentum, a combination of TVC and surface deflection to have that radical a pitch up maneuver would be outright suicidal, as in leaving controlled flight. Of those six factors, ALL of them matters equally. Airspeed is not the most important. Altitude is not the most important. And so on. ALL of them are equally important in that calculating loop. So if surface deflections are enough to turn my jet over it maximum safe angle-of-attack, any additional TVC to that would be redundant and unnecessarily dangerous.

Here is what most non-pilots do not understand: ALL maneuvers are dangerous.

Even in a prop jobber like the Cessna 150, of which I learned to fly, a simple aileron roll involves complex subconscious awareness of those six factors. The pilot -- me -- is in place of complex avionics. When I initiate the aileron roll, I have to compensate for an initial loss of altitude and adjust throttle to compensate. Same awareness for making a coordinated turn: An aileron and rudder combination. Modern avionics take most of that 'grunt' work from the pilot.

Pugachev was an exceptional pilot and I do not want to take any of his hard earned skills from him. But if he is an exceptional pilot, it is because he knows the precisely the combination of commands and responses (from the jet) to execute dangerous maneuvers without departing controlled flight. The -27 is already an exceptional jet in terms of maneuverability so there was no need for TVC to initiate the pitch up, and from watching the maneuver many times and what I know of flight controls avionics, I am convinced that he used flight control surfaces to initiate the maneuver, then used TVC to recover/prevent the -27 from completely flipping over.

How effective is this capability ? If against an opponent that cannot go above 4-5g which would require a lot of airspace to make a turn, then the maneuver would be advantageous in repositioning the -27 for a good shot. But against an F-16 class fighter ? The loss of speed which equals to loss of energy to maneuver, the -27 would be as good as dead.

Thrust vectoring can be helpful in combat maneuvers but the Cobra maneuver is NOT for combat.