Following on exploratory developments in flight-testing techniques and data-analysis procedures for helicopter external noise, extensive measurements of noise characteristics and associated flight-path data have been made by RAE on several helicopters in various operational modes, with repeated flight trajectories over longitudinal and lateral arrays of ground-based microphones under quiet airfield conditions. This analysis presents some experimental results from Lynx aircraft with standard rotor configurations, being concerned primarily with the influence of different operating procedures on both main-rotor and tail-rotor noise characteristics and on measurement repeatability during level-flight, oblique landing-approach, and oblique take-off. Some tail-rotor near-field noise signatures have also been derived for correlation purposes, using a microphone mounted with a forward-facing nose-cone just outside the fuselage skin on the tail-boom.


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    Title :

    The Influence of Helicopter Operating Conditions on Rotor Noise Characteristics and Measurement Repeatability


    Contributors:
    M. R. P. Law (author) / J. Williams (author)

    Publication date :

    1982


    Size :

    63 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English