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Improvement of the predicted aural detection code ICHIN (I Can Hear It Now)Acoustic tests were conducted to study the far-field sound pressure levels and aural detection ranges associated with a Sikorsky S-76A helicopter in straight and level flight at various advancing blade tip Mach numbers. The flight altitude was nominally 150 meters above ground level. This paper compares the normalized predicted aural detection distances, based on the measured far-field sound pressure levels, to the normalized measured aural detection distances obtained from sound jury response measurements obtained during the same test. Both unmodified and modified versions of the prediction code ICHIN-6 (I Can Hear It Now) were used to produce the results for this study.
Document ID
Document Type
Conference Paper
Mueller, Arnold W.
(NASA Langley Research Center Hampton, VA, US, United States)
Smith, Charles D.
(Lockheed Engineering and Sciences Co., Hampton, VA US, United States)
Lemasurier, Phillip
(Sikorsky Aircraft Co., Stratford, CT US, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
ISSN: 0736-2935
Subject Category
Accession Number
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