The design of a helicopter is based on an understanding of many parameters and their interactions. For example, in the design stage of a helicopter, the weight, engine, and rotor speed must be considered along with the rotor geometry when considering helicopter operations. However, the relationship between the noise radiated from the helicopter and these parameters is not well understood, with only limited model and full-scale test data to study. In general, these data have shown that reduced rotor speeds result in reduced far-field noise levels. This paper reviews the status of a recent helicopter noise research project designed to provide experimental flight data to be used to better understand helicopter rotor-speed effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a McDonnell Douglas model 500E helicopter operating with the rotor speed as the control variable over the range of 103% of the main-rotor speed (NR) to 75% NR, and with the forward speed maintained at a constant value of 80 knots.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Helicopter main-rotor speed effects on far-field acoustic levels


    Contributors:

    Publication date :

    1987-10-01


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English


    Keywords :


    Helicopter Main-Rotor Speed Effects on Far-Field Acoustic Levels

    A. W. Mueller / O. S. Childress / M. Hardesty | NTIS | 1987


    HELICOPTER MAIN ROTOR

    KORZH NIKOLAJ AFANASEVICH | European Patent Office | 2017

    Free access



    Helicopter far-field acoustic levels as a function of reduced main-rotor advancing blade-tip Mach number

    Mueller, Arnold W. / Smith, Charles D. / Lemasurier, Philip | NTRS | 1990