Test flights using a twin-engine, high-wing, light STOL transport plane powered by free turbine engines driving three-bladed propellers, were conducted at the NASA Wallops Flight Center. A ground-based acoustic measuring range was set up, and aircraft tracking information was supplied by a radar system. The noise of the unshrouded propeller was measured under static and forward flight conditions, and the measurements were compared with theory. Under static conditions, the principal noise is related to the unsteady loading associated with the interaction of the propeller with persistent turbulent eddies passing through the propeller disk. Through the use of existing prediction techniques, it was shown that changes in the geometry such as different airfoil thickness distribution can affect the radiated acoustic pressure signatures. This test program confirmed that lower propeller noise levels are produced in forward flight than under static conditions and that the most significant reductions occur at the midfrequencies which dominate perceived and A-weighted noise levels.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen


    Exportieren, teilen und zitieren



    Titel :

    Some measured and calculated effects of forward velocity on propeller noise


    Beteiligte:
    Pegg, R. J. (Autor:in) / Farassat, F. (Autor:in) / Magliozzi, B. (Autor:in)

    Kongress:

    Gas Turbine Conference and Products Show ; 1977 ; Philadelphia, PA


    Erscheinungsdatum :

    1977-03-01


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Keine Angabe


    Sprache :

    Englisch




    Forward Rotor Vortex Location Effects on Counter Rotating Propeller Noise

    Laur, M. N. / Squires, R. L. / Nagel, R. T. et al. | British Library Conference Proceedings | 1992



    Analysis of Calculated and Measured Wake Characteristics of a Propeller-Wing Model

    Veldhuis, L. L. M. / Nebiolo, S. / AIAA | British Library Conference Proceedings | 2000