A jet-diffuser ejector for a V/STOL fighter

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A jet-diffuser ejector for a V/STOL fighter

Alperin, M. / Wu, J.J.

The jet-diffuser was integrated into the General Dynamics Corp. E205 fighter/attack aircraft to provide a VTOL capability for the aircraft. Some modifications of the ejector design were required to achieve the integration and stowage required for avoidance of deleterious effects on the aircraft performance during conventional flight. The ejector is designed to operate at a nozzle pressure ratio of 3 with an expected thrust augmentation of 1.95. The necessary thrust force for transition to conventional flight was to be achieved by a unique system consisting of vector control jets and a diffuser flap. This system was intended to provide a rearward deflection of the effluent flow and a corresponding thrust force in the flight direction. A single ejector equipped with only one vector control jet and a diffuser flap was installed close to the leading edge of aircraft, without wing, canard or tail surface. Tests of the system at a nozzle pressure ratio of 1.24 indicated a thrust augmentation of 1.92 and a thrust in the flight direction of about 12 % of the total thrust under static conditions. An ejector stall occurred at a ratio of tunnel dynamic pressure to nozzle gage pressure of about 0.008. Ejector stall speed can be delayed by using a boundary layer control jet at the front inlet lip of the ejector. (DePo)