Several noise sources combine to make up the total helicopter noise spectrum. The sources that are most important to community annoyance are the tail rotor (discrete), main rotor (unsteady), and engine (unsteady). The periodic and broadband noise components of the helicopter rotor were enumerated, and an approach to rotorcraft noise prediction was discussed. Helicopter noise sources were prioritized, and design improvements to reduce noise were reviewed. Main rotor noise is believed to be the key to quieter helicopters since there are proven and relatively inexpensive ways to handle the tail rotor. Blade Vortex Interaction (BVI) noise is a problem to some extent with all helicopters, particularly in the descent mode. Methodology must be developed to allow forecast and control of this type of noise. Additional means of controlling it, such as reduced rotor speeds for terminal operations should also be pursued because they may be the most effective means of control and they apply to all helicopter models. Main rotor broadband noise is the limiting factor in overall helicopter noise generation. Development of semi-empirical methods to predict its behavior is necessary if results are to be achieved in the short time period available.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Priority for empirical methods development


    Contributors:
    King, R. J. (author)


    Publication date :

    1982-07-01


    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English


    Keywords :


    Empirical Evaluation of Transit Signal Priority

    Feng, Wei / Figliozzi, Miguel / Bertini, Robert L. | Transportation Research Record | 2019


    Road Safety Benefits from Bus Priority: An Empirical Study

    Goh, Kelvin Chun Keong | Online Contents | 2013




    Analytical and Empirical Evaluation of Freight Priority System in Connected Vehicle Environment

    Talukder, Md Abu Sufian / Tedla, Elsa G. / Hainen, Alexander M. et al. | ASCE | 2022