NASA LaRC personnel have conducted a strudy of the predicted acoustic detection ranges associated with reduced helicopter main rotor speeds. This was accomplished by providing identical input information to both the aural detection program ICHIN 6, (I Can Hear It Now, version 6) and the electronic acoustic detection program ARCAS (Assessment of Rotorcraft Detection by Acoustics Sensing). In this study, it was concluded that reducing the main rotor speed of the helicopter by 27 percent reduced both the predicted aural and electronic detection ranges by approximately 50 percent. Additionally, ARCAS was observed to function better with narrowband spectral input than with one-third octave band spectral inputs and the predicted electronic range of acoustic detection is greater than the predicted aural detection range.
Helicopter Main-Rotor Speed Effects: A Comparison of Predicted Ranges of Detection from the Aural Detection Program ICHIN and the Electronic Detection Program ARCAS
1991
16 pages
Report
No indication
English
Aircraft , Acoustic Detection , Lifting rotors , Noise prediction (Aircraft) , Noise reduction , Rotor speed , Applications programs (Computers) , Noise threshold , Signal to noise ratios , Aircraft detection , Computerized simulation , Narrowband , Noise spectra , Oh-6 helicopter , Prediction analysis techniques
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