High Pressure Bleed for STOL and STO-VL Performance - A Conceptual Examination.

The engines in modern combat aircraft are sized by combat maneuverability considerations. These aircraft therefore have much more thrust available than is needed at normal takeoff and landing speeds. Only the Harrier, which can vector the thrust of the centrally-mounted engine through the center of gravity can use its excess thrust to reduce the takeoff and landing distance to zero at low operating weights. The engines on the others are too far aft for direct thrust vectoring. This paper examines other possibilities. The main emphasis is on the possibility of using bleed air from the high pressure compressor to blow the wing andor a canard for STOL performance. Alternately, the use of this high pressure bleed to drive fold-out fans to achieve STO-VL performance is also examined. Author