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Development of rotorcraft interior noise control concepts. Phase 2: Full scale testing, revision 1The phase 2 effort consisted of a series of ground and flight test measurements to obtain data for validation of the Statistical Energy Analysis (SEA) model. Included in the gound tests were various transfer function measurements between vibratory and acoustic subsystems, vibration and acoustic decay rate measurements, and coherent source measurements. The bulk of these, the vibration transfer functions, were used for SEA model validation, while the others provided information for characterization of damping and reverberation time of the subsystems. The flight test program included measurements of cabin and cockpit sound pressure level, frame and panel vibration level, and vibration levels at the main transmission attachment locations. Comparisons between measured and predicted subsystem excitation levels from both ground and flight testing were evaluated. The ground test data show good correlation with predictions of vibration levels throughout the cabin overhead for all excitations. The flight test results also indicate excellent correlation of inflight sound pressure measurements to sound pressure levels predicted by the SEA model, where the average aircraft speech interference level is predicted within 0.2 dB.
Document ID
19880005387
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Yoerkie, C. A. (United Technologies Corp. Stratford, CT., United States)
Gintoli, P. J. (United Technologies Corp. Stratford, CT., United States)
Moore, J. A. (Cambridge Collaborative, Inc. Mass., United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1986
Subject Category
Acoustics
Report/Patent Number
NASA-CR-172594-REV-1
NAS 1.26:172594-REV-1
SER-760703
Accession Number
88N14769
Funding Number(s)
CONTRACT_GRANT: NAS1-16932
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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