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Evaluation of helicopter noise due to b blade-vortex interaction for five tip configurationsThe effect of tip shape modification on blade vortex interaction induced helicopter blade slap noise was investigated. Simulated flight and descent velocities which have been shown to produce blade slap were tested. Aerodynamic performance parameters of the rotor system were monitored to ensure properly matched flight conditions among the tip shapes. The tunnel was operated in the open throat configuration with treatment to improve the acoustic characteristics of the test chamber. Four promising tips were used along with a standard square tip as a baseline configuration. A detailed acoustic evaluation on the same rotor system of the relative applicability of the various tip configurations for blade slap noise reduction is provided.
Document ID
19800006582
Document Type
Technical Publication (TP)
Authors
Hoad, D. R.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 4, 2013
Publication Date
December 1, 1979
Subject Category
Acoustics
Report/Patent Number
L-13207
NASA-TP-1608
AVRADCOM-TR-80-B-1
Accession Number
80N14840
Funding Number(s)
PROJECT: RTOP 505-10-23-05
PROJECT: DA PROJ. 1L2-62209-AH-76
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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