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Vibration analysis of the SA349/2 helicopterHelicopter airframe vibration is examined using calculations and measurements for the SA349/2 research helicopter. The hub loads, which transmit excitations to the fuselage, are predicted using a comprehensive rotorcraft analysis and correlated with measuring hub loads. The predicted and measured hub loads are then coupled with finite element models representing the SA349/2 fuselage. The resulting vertical acceleration at the pilot seat is examined. Adjustments are made to the airframe structural models to examine the sensitivity of predicted vertical acceleration to the model. Changes of a few percent to the damping and frequency of specific models lead to large reductions in predicted vibration, and to major improvements in the correlations with measured pilot-seat vertical acceleration.
Document ID
19910021764
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Heffernan, Ruth
(NASA Ames Research Center Moffett Field, CA., United States)
Precetti, Dominique
(Service Technique des Programmes Aeronautiques Paris (France)., United States)
Johnson, Wayne
(Johnson Aeronautics Palo Alto, CA., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1991
Subject Category
Aeronautics (General)
Report/Patent Number
NAS 1.15:102794
A-90083
NASA-TM-102794
Accession Number
91N31078
Funding Number(s)
PROJECT: RTOP 505-61-51
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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