Main rotor blades of the dual, counter-rotating, rigid coaxial rotor system exhibit a unique unconventional combination of positive and negative twist gradients in which the rotor system rotor Figure of Merit (hover efficiency) is improved by providing a dissimilar twist distribution between the lower rotor blade (20L) and the upper rotor blades (20U). This improvement is specifically a result of reduced profile drag of the lower rotor system, achieved by driving the effective operating condition of the lower rotor blades to be similar to the upper rotor blade such that the tip drag losses of the lower main rotor have been reduced considerably using a mathematically vigorous approach. While minimal induced power consumption resulted due to the dissimilar lower main rotor twist, a significant profile power benefit is realized, resulting in the improved hover efficiency with essentially no reduction in rotor forward flight performance.


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    Title :

    ROTOR BLADE TWIST DISTRIBUTION FOR A HIGH SPEED ROTARY-WING AIRCRAFT


    Additional title:

    ROTORBLATTTORSIONSVERLAUF FÜR EINEN HOCHGESCHWINDIGKEITSDREHFLÜGLER
    RÉPARTITION DE LA TORSION DE PALE D'AÉRONEF À VOILURE TOURNANTE À GRANDE VITESSE


    Contributors:

    Publication date :

    2019-11-06


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    IPC:    B64C AEROPLANES , Flugzeuge



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