This study starts with the design of a reversible airfoil rib for stopped-rotor applications, where the sharp trailing-edge morphs into the rounded leading-edge, and vice-versa. A NACA0012 airfoil is approximated in a piecewise linear manner and straight, rigid outer profile links used to define the airfoil contour. The end points of the profile links connect to control links, each set on a central actuation rod via an offset. Chordwise motion of the actuation rod moves the control and the profile links and reverses the airfoil. The paper describes the design methodology and evolution of the final design, based on which two reversible airfoil ribs were fabricated and used to assemble a finite span reversible rotor/wing demonstrator. The profile links were connected by Aluminum strips running in the spanwise direction which provided stiffness as well as support for a pre-tensioned elastomeric skin. An inter-rib connector with a curved-front nose piece supports the leading-edge. The model functioned well and was able to reverse smoothly back-and-forth, on application and reversal of a voltage to the motor. Navier–Stokes CFD simulations (using the TURNS code) show that the drag coefficient of the reversible airfoil (which had a 13% maximum thickness due to the thickness of the profile links) was comparable to that of the NACA0013 airfoil. The drag of a 16% thick elliptical airfoil was, on average, about twice as large, while that of a NACA0012 in reverse flow was 4–5 times as large, even prior to stall. The maximum lift coefficient of the reversible airfoil was lower than the elliptical airfoil, but higher than the NACA0012 in reverse flow operation.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Reversible airfoils for stopped rotors in high speed flight


    Weitere Titelangaben:

    Reversible Tragflügel für angehaltene Rotoren beim Hochgeschwindigkeitsflug


    Beteiligte:

    Erschienen in:

    Smart Materials and Structures ; 23 , 11 ; 115013/1-115013/12


    Erscheinungsdatum :

    2014


    Format / Umfang :

    12 Seiten, 14 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch




    Reversible Airfoils for Stopped Rotors in High Speed Flight

    Niemiec, R. / Jacobellis, G. / Gandhi, F. et al. | British Library Conference Proceedings | 2014


    CONVERTIPLANE WITH STOPPED ROTORS, AND REPOSITIONABLE ROTOR BLADES

    BROWN GERALD E | Europäisches Patentamt | 2023

    Freier Zugriff

    Blade response simulations of flap controlled stopped rotors

    Yillikci, Y. / Prasad, J. / Hanagud, S. et al. | AIAA | 1993