A test was conducted in the NASA Ames 7- by 10-Foot Wind Tunnel to derive aerodynamic spring and damping estimates for free-pitching tips on a semispan wing. The test model was a rectangular planform semispan wing with wing tips that had a single rigid-body pitch degree of freedom with respect to the inboard wing. A number of different tip planform geometries were tested, incorporating a range of quarter-chord sweep angles and taper ratios. The wing-tip dynamic response characteristics were measured at several wing angles of attack and tunnel dynamic pressures. The tip oscillations were initiated by releasing the tips from prescribed angles of attack. A new method to isolate Coulomb damping from aerodynamic damping from these tip-motion time histories is developed and applied. Correlations were performed between the experimentally derived wing-tip aerodynamic spring and damping values and predictions from a semiempirical analysis based on steady-state tip aerodynamic loads.


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    Title :

    Aerodynamic Spring and Damping of Free-Pitching Tips on a Semispan Wing


    Contributors:

    Conference:

    Dynamics Specialist Conference ; 1992 ; Dallas, TX, United States


    Publication date :

    1992-01-01


    Type of media :

    Preprint


    Type of material :

    No indication


    Language :

    English


    Keywords :



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