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Acoustic test of a model rotor and tail rotor: Results for the isolated rotors and combined configurationAcoustic data from a model scale main rotor and tail rotor experiment in the NASA Langley 14 by 22 Foot Subsonic Tunnel are presented for the main rotor and trail rotor in isolation and for the two rotors operating together. Results for the isolated main rotor show the importance of the rotor flapping conditions on mid-frequency noise content. High levels of main rotor retreating side blade-vortex interaction noise are shown to radiate downstream of the model. The isolated tail rotor noise results show the dominance of harmonic noise in the thrusting direction. The occurrence of tail rotor broadband noise is seen by the broadening of the tail rotor harmonics and is attributed to fuselage wake turbulence. The combined main and tail rotor data are presented to show the dominance of each rotor's different noise sources at different directivity locations.
Document ID
19890011406
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Martin, R. M. (NASA Langley Research Center Hampton, VA, United States)
Burley, C. L. (NASA Langley Research Center Hampton, VA, United States)
Elliott, J. W. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1989
Subject Category
Acoustics
Report/Patent Number
NASA-TM-101550
NAS 1.15:101550
Accession Number
89N20777
Funding Number(s)
PROJECT: RTOP 505-63-51
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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