This paper presents a fundamental, analytical study that identifies the sources that contribute to helicopter rotor hub inplane vibratory shears. One of the major approaches to helicopter vibration reduction is to reduce these inplane vibratory shears through the addition of external mechanical devices (bifilar pendulum absorbers, etc.). For example, Sikorsky Aircraft has achieved its goal by adding on two sets of bifilars to its S-76 hub. The present goal is to provide a fundamental understanding of the inplane shear problem. A systematic approach is presently followed which attacks the basic inplane hub shears and dissects them for a four-bladed articulated rotor. It is noted that the blade chordwise inplane shear is the important shear. This chordwisse inplane shear has three major components, namely, the aerodynamic component, the Coriolis contribution, and the inertial component. Based on simplified equations and numerical estimation, it is subsequently found that the chordwise inplane shear, and consequently, the hub inplane shears are strongly dependent on the out-of-plane response. The present paper explains this new, analytical finding.


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    Title :

    Sources of helicopter rotor hub inplane shears


    Additional title:

    Der Grund für Schubbeanspruchungen an Hubschrauberrotoren innerhalb der Nabenebene


    Contributors:


    Publication date :

    1993


    Size :

    8 Seiten, 4 Tabellen, 6 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English








    STIFF INPLANE ELASTROMERIC ROTOR HEAD

    SCHMALING DAVID N / D ANNA FRANK P | European Patent Office | 2015

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