Development of a Technique for Realistic Prediction and Electronic Synthesis of Helicopter Rotor Noise
ROCHESTER APPLIED SCIENCE ASSOCIATES NY
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A helicopter rotor noise prediction program was developed so that the acoustic characteristics of new, untested rotor designs could be evaluated as well as the effects of basic rotor design changes on the acoustic signature of existing rotors. The prediction program is general enough to be able to consider future designs in hover and steady state flight for any observer location. The program output is the digital pressure time history produced by the helicopter rotors at the observer location. This pressure time history corresponds to that which would be recorded by a microphone place at the observer location. The program output can be Fourier analyzed so that the noise spectrum can be generated. The digital pressure time history can also be converted to an analog signal for subjective evaluation.