Interest in high speed rotorcraft has directed attention toward the slowed-rotor, high advance ratio compound autogyro concept. Inherent features of this concept include partially unloading and slowing the rotor while maintaining autorotation. Unloading of the rotor results from transfer of the lift generation function to the more aerodynamically efficient wing at high flight speed, and slowing of the rotor is required to avoid sonic conditions on the advancing blade. This necessity for a reduction in rotor speed with increasing flight speed results in high advance ratio operation where the retreating side of the rotor is dominated by the reverse flow region. The use of conventional swashplate controls has been proposed as a means to unload and slow the rotor, as well as suppress large hub moments due to cyclic blade flapping. Rotors with low Lock number and high flapping stiffness were investigated in simulated wind tunnel experiments using the FLIGHTLAB rotorcraft modeling software. Performance analysis for rotors trimmed to autorotate with zero average hub pitching and rolling moments indicates that reduced rotor thrust is achieved primarily through rotor speed reduction at a lower shaft incidence angle with respect to the freestream velocity, and imposing hub moment trim constraints results in a thrust increment sign reversal with collective pitch angle above advance ratio my nearly equal 1.0. Rotor control strategies are developed including the use of variable shaft incidence to achieve rotor speed control while hub moment suppression is achieved through cyclic control. Quasi-steady analysis of a commanded rotor speed transition is presented for cases with and without hub moment suppression, further supporting the use of variable shaft incidence.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Performance and trim analysis of lightly loaded rotors in high advance ratio autorotation


    Additional title:

    Leistungs- und Trimmanalyse von schwach belasteten Rotoren im Autorotationsflug mit hohem Steigungsverhalten


    Contributors:


    Publication date :

    2010


    Size :

    23 Seiten, 26 Bilder, 3 Tabellen, 15 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Performance and Trim Analysis of Lightly Loaded Rotors in High Advance Ratio Autorotation

    Rigsby, J. / Prasad, J.V.R. / AHS International | British Library Conference Proceedings | 2010


    Stability and Control Issues Associated with Lightly-Loaded Autorotating Rotors in High Advance Ratio Flight

    Rigsby, J. / Prasad, J. / AHS International | British Library Conference Proceedings | 2008


    Ejection seat landing through autorotation rotors and working method of ejection seat

    WU YUANHANG / LI XIAOGUANG / ZHU QINGHUA et al. | European Patent Office | 2021

    Free access

    Autorotation Concerns

    Online Contents | 2003


    Autorotation of fuselages

    Clarkson, M.H. | Engineering Index Backfile | 1958