Noise evaluation of four exhaust nozzles for afterburning turbojet engine

Sea level static tests were made of three different nozzle designs suitable for applica- T y p e o f Report and Period Covered Technical Memorandum Sponsoring Agency Codetion to a supersonic cruise aircraft.At military power, results obtained with a plug nozzle, a variable flap ejector, and an auxiliary inlet ejector were compared with that of a convergent primary nozzle.At maximum afterburning only the primary and two ejector nozzles were tested.Based on the noise measurements made, it was calculated that for a flyover at 1000 f t (304.8 m) altitude, the maximum perceived noise level on the ground would be 6 dB less with the plug nozzle than with the auxiliary inlet ejector.17.K a y Words ( S u g g e s t e d by Author(s)) J e t noise Variable flap ejector Exhaust nozzle Perceived noise Afterburning turbojet takeoff evaluation Plug nozzle Auxiliary inlet Supersonic cruise ejector 18.