Vibration levels have a problem in helicopters since their inception. The reason for this lies in the method whereby the helicopter generates its lift, namely, the rotor system. As the rotor blades rotate they encounter a continuously changing aerodynamic environment which results in a continuously changing environment which results in a continuously changing aerodynamic loading on the blades. This changing environment is repeated on each revolution of the rotor. Hence, the rotor develops aerodynamic loads which are oscillatory in nature. These oscillatory loads are transferred directly to the helicopter airframe through the mechanical connection of the rotor to the airframe, i.e., the rotor-shaft/transmission attachment. Oscillatory loads are also transmitted to the airframe by impingement of the rotor wake on the upper portion of the airframe, but the mechanically transferred loads are in most cases much more significant than the aerodynamically transferred loads.


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    Title :

    On the use of active higher harmonic blade pitch control for helicopter vibration reduction


    Additional title:

    Anwendung eines hoeheren, harmonischen Blattwinkels und seiner Kontrolle zur Verringerung der Vibration bei Hubschraubern


    Contributors:
    Hammond, C.E. (author) / Cline, J.E. (author)

    Published in:

    Publication date :

    1980


    Size :

    17 Seiten


    Type of media :

    Report


    Type of material :

    Print


    Language :

    English