Leading-edge extension

[citation needed] Many high-performance aircraft use the dogtooth design, which induces a vortex over the wing to control boundary layer spanwise extension, increasing lift and improving resistance to stall.

Some of the best-known uses of the dogtooth are in the stabilizer of the F-15 Eagle and the wings of the F-4 Phantom II, F/A-18 Super Hornet, CF-105 Arrow, F-8 Crusader, and the Ilyushin Il-62.

On a modern fighter aircraft, LERXes induce controlled airflow over the wing at high angles of attack, so delaying the stall and consequent loss of lift.

However, at high angles of attack, as often encountered in a dogfight or during takeoff and landing, the LERX generates a high-speed vortex that attaches to the top of the wing.

[4] Otherwise they operate on the same principles as the LERX system to create lift augmenting leading edge vortices during high angle of attack flight.

[dubious – discuss][citation needed] Additionally, on the Sukhoi Su-57 the LEVCON system is used for increased departure-resistance in the event of TVC failure at a post-stall attitude.