Accession Number : ADA134612

Title :   Aeromechanical Stability of a Hingeless Rotor in Hover and Forward Flight: Analysis and Wind Tunnel Tests.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER

Personal Author(s) : Yeager,William T , Jr ; Hamouda,M-Nabil H ; Mantay,Wayne R

PDF Url : ADA134612

Report Date : Aug 1983

Pagination or Media Count : 21

Abstract : A research effort of analysis and testing has been conducted in the NASA-Langley Transonic Dynamics Tunnel to investigate the ground resonance phenomenon of a soft in-plane hingeless rotor. Experimental data were obtained using a 9 ft. (2.74 m) diameter model rotor in hover and forward flight. Eight model rotor configurations were investigated. Configuration parameters included pitch-flap coupling, blade sweep and droop, and precone of the blade feathering axis. An analysis based on a comprehensive analytical model of rotorcraft aerodynamics and dynamics was used for this study. The moving-block method was used to experimentally determine the regressing lead-lag mode damping. Good agreement has been obtained between the analysis and test. Both analysis and experiment indicated ground resonance instability in hover. The paper presents an outline of the analysis, a description of the experimental model and procedures, and comparison of the analytical and experimental data. (Author)

Descriptors :   *Rotor blades(Rotary wings), *Helicopter rotors, *Resonance, Stability, Coupling(Interaction), Oscillation, Airframes, Hingeless, Helicopters, Hubs, Flexural properties, Excitation, Resonant frequency, Vibration, Damping, Hovering, Flight paths, Ground level, Aerodynamic loading, Mechanics, Wind tunnel tests, Computer programs

Subject Categories : Aerodynamics
      Helicopters
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE