Predictions and measurements of stability, control angles and loads for an isolated hingeless rotor are presented to illustrate the effects of aerodynamic modeling. The test model has four soft-inplane, soft-torsion blades and was tested at a realistic tip speed in the range of existing flight vehicles. Key measurements in the database include the cyclic pitch controls, steady root-flap moment and regressive lag-mode damping for two coning angles with advance ratio, shaft angle and collective pitch variations. A modal approach with both nonrotating and rotating modes, the ONERA dynamic stall models of lift, drag and pitching moment, and a three-dimensional finite-state wake model are used. The cyclic pitch controls and the corresponding periodic responses are predicted by the periodic shooting method with damped Newton iteration; this method is based on the fast-Floquet theory and generates the equivalent Floquet transition matrix (EFTM) as a by-product. The eigenvalues and eigenvectors of the EFTM provide the frequencies and damping levels. The steady root-flap moment is calculated by both the force-integration and mode-deflection methods. A major finding is that including a finite-state wake model dramatically improves the prediction of the lateral cyclic pitch control.


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    Titel :

    Correlation of several aerodynamic models and measurements of hingeless-rotor trim and stability


    Beteiligte:
    Subramanian, S. (Autor:in) / Ma, G. (Autor:in) / Gaonkar, G.H. (Autor:in) / Maier, T.H. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    2000


    Format / Umfang :

    12 Seiten, 12 Bilder, 8 Tabellen, 20 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch