A set of coupled periodic nonlinear differential flap-lag-torsional equations of blade motion is described which can simulate a blade having a precone, twist, distributed torsion, root torsion, torque offset, blade-root offsets, and offsets among the elastic axis, the aerodynamic center, and the blade cross-sectional center of mass. It is noted that the aerodynamic loads derived for these equations are applicable to cases of both hover and forward flight. The aeroelastic stability of a hingeless helicopter blade is investigated by linearizing the nonlinear differential equations of motion about a time-dependent equilibrium position of the helicopter in forward flight, using propulsion and moment trim procedures. A comparison of the results with those obtained previously for coupled flap-lag-torsional boundaries in hover indicates that aeroelastic-stability margins are degraded due to forward flight.


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    Title :

    Aeroelastic stability of coupled flap-lag-torsional motion of helicopter rotor blades in forward flight


    Contributors:

    Conference:

    Conference on Structures, Structural Dynamics and Materials ; 1977 ; San Diego, CA, US


    Publication date :

    1977-01-01


    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English





    Aeroelastic characteristics for jet-flap helicopter rotor in forward flight

    White, Jr., R.P. / Trenka, A.R. | Engineering Index Backfile | 1962


    Coupled flap-lag-torsional dynamics of hingeless rotor blades in forward flight

    Friedmann, P. P. / Kottapalli, S. B. R. | NTRS | 1982



    THE AEROELASTIC CHARACTERISTICS OF A JET-FLAP HELICOPTER ROTOR IN FORWARD FLIGHT*

    Trenka, Andrew R. / White, Richard P. | SAE Technical Papers | 1962