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An experimental investigation of hingeless helicopter rotor-body stability in hoverModel tests of a 1.62 m diameter rotor were performed to investigate the aeromechanical stability of coupled rotor-body systems in hover. Experimental measurements were made of modal frequencies and damping over a wide range of rotor speeds. Good data were obtained for the frequencies of the rotor lead-lag regressing mode. The quality of the damping measurements of the body modes was poor due to nonlinear damping in the gimbal ball bearings. Simulated vacuum testing was performed using substitute blades of tantalum that reduced the effective lock number to 0.2% of the model scale value while keeping the blade inertia constant. The experimental data were compared with theoretical predictions, and the correlation was in general very good.
Document ID
19780021101
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Bousman, W. G.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 3, 2013
Publication Date
June 1, 1978
Subject Category
Aeronautics (General)
Report/Patent Number
AVRADCOM-TR-78-17(AM)
NASA-TM-78489
A-7430
Accession Number
78N29044
Funding Number(s)
PROJECT: RTOP 992-21-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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