# Can the HAL Lca Tejas perform Pugachev's Cobra maneuver?

Can any variant of the HAL Lca Tejas (either the naval variant, the mark 1, mark 2 or later) perform Pugachev's Cobra? If not, why?

• Please clarify - do you mean this aircraft? en.wikipedia.org/wiki/HAL_Tejas
– Andy
Sep 9 '15 at 10:43
• Yes, of course! Mar 26 '17 at 9:07

No.

With that delta wing shape it will have pitch control problems at higher angles of attack. The Cobra maneuver requires a small pitch-down moment over the post-stall region up to 110° angle of attack. I very much doubt that this wing planform will have such pitch characteristics, and without thrust vector control a docile pitch behavior is a prerequisite for the Cobra maneuver.

In the development of the LCA a high lift coefficient without leading edge devices was the main goal of the wing design. It should be able to operate in the vicinity of flocks of birds - birdstrike is a real risk on many Indian Air Force bases. At the same time, the small aircraft should be able to fly supersonically, which lead to the double-delta wing as the best way to achieve both goals, and poor post-stall pitch response had to be accepted.

When HAL switched from MBB to Dassault for technical support, leading edge devices were added in order to fulfil the take-off and landing requirements. Post-stall flight was not seriously considered at any point in the development.

• You are genius! Mar 26 '17 at 5:13
• Clear and lucid explanation, Thank you very much for your precious time! Mar 26 '17 at 5:24
• I read here that it does have thrust vectoring. May 28 at 22:04
• @TomMcW I've read it too but cannot find a second source. The nozzle on Tejas pictures looks awfully conventional to me, so I suspect the AFTech writer has got it wrong. May 29 at 4:38

No known variant of the HAL Tejas can perform the Cobra Maneuver.

This is for the simple reason that the aircraft was not designed nor was it expected to perform such a maneuver.

In a Cobra, the plane suddenly raises the nose to the veritical position (or beyond, usually 90$^{\circ}$ to 120$^{\circ}$) before dropping it back to the normal flight, maintaining more or less the same altitude through the entire maneuver.