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.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

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


    Contributors:

    Published in:

    Journal of Aircraft ; 58 , 1 ; 43-52


    Publication date :

    2020-06-30


    Size :

    10 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Flight Testing of a Coaxial Ultralight Rotorcraft

    Feil, R., Rinker, M., Hajek, M. | BASE | 2017

    Free access

    Rotorcraft aeromechanics

    Johnson, Wayne | TIBKAT | 2013


    Milestones in Rotorcraft Aeromechanics

    Johnson, Wayne | NTRS | 2011