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Subjective field study of response to impulsive helicopter noiseSubjects, located outdoors and indoors, judged the noisiness and other subjective noise characteristics of flyovers of two helicopters and a propeller driven airplane as part of a study of the effects of impulsiveness on the subjective response to helicopter noise. In the first experiment, the impulsive characteristics of one helicopter was controlled by varying the main rotor speed while maintaining a constant airspeed in level flight. The second experiment which utilized only the helicopters, included descent and level flight operations. The more impulsive helicopter was consistently judged less noisy than the less impulsive helicopter at equal effective perceived noise levels (EPNL). The ability of EPNL to predict noisiness was not improved by the addition of either of two proposed impulse corrections. A subjective measure of impulsiveness, however, which was not significantly related to the proposed impulse corrections, was found to improve the predictive ability of EPNL.
Document ID
Document Type
Technical Publication (TP)
Powell, C. A.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 4, 2013
Publication Date
April 1, 1981
Subject Category
Report/Patent Number
Accession Number
Funding Number(s)
PROJECT: RTOP 505-35-13-01
Distribution Limits
Work of the US Gov. Public Use Permitted.
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