This work presents the aeromechanics analysis and evaluation of an ultralight counter-rotating coaxial rotorcraft using a combined numerical and experimental approach with a focus on turn, climb, and descent flight conditions. The helicopter features a 2-by-2 bladed coaxial rotor system with teeter hinges, 6.5 m in diameter and uniform airfoil sections of the linearly twisted blades. Hover and forward-flight test data are shown with varying turn rates or climb and descent velocities. The predictive capabilities of a CAMRAD II numerical model are used to extend and support the flight test data and evaluate possible flight-envelope limitations in terms of ceiling limits and maximum climb rates. The paper focuses on rotor performance, thrust, horizontal-stabilizer loads, and blade-tip clearance, with special attention on the effects from interactional rotor aerodynamics. Results in terms of rotor performance, rotor thrust, horizontal-stabilizer loads, and rotorcraft aerodynamic angles of attack resulted in satisfactory correlation between the numerical model and the measurements. Rotor–rotor interactional effects contributed to the approaching rotor-blade tips, especially during low-speed descent flights. During turn flight, required rotor power increases with greater bank angles. Maximum axial climb rate of the ultralight coaxial helicopter was at 4.24    m / s , the hover ceiling at 2180 m, and the service ceiling at 4450 m. Ceiling limitations depended on the operating conditions and reduced with greater temperature and rotorcraft weight.


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    Titel :

    Aeromechanics of a Coaxial Ultralight Rotorcraft During Turn, Climb, and Descent Flight


    Beteiligte:
    Feil, Roland (Autor:in) / Hajek, Manfred (Autor:in)

    Erschienen in:

    Journal of Aircraft ; 58 , 1 ; 43-52


    Erscheinungsdatum :

    2020-06-30


    Format / Umfang :

    10 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch




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