Forced oscillation tests over a large angle-of-attack range for an F-18 model are conducted in the NASA Langley 12-foot low-speed tunnel. The resulting dynamic longitudinal data are analyzed with an unsteady aerodynamic modeling method based on Fourier functional analysis and the indicial formulation. The method is extensively examined and improved to automate the calculation of model coefficients, and to evaluate more accurately the indicial integral. The results indicate that the general model equation obtained from harmonic test data in a range of reduced frequency is capable of accurately modeling the nonlinear responses with large hysteresis effect, except in the region where a delayed flow reattachment occurs at low angles of attack in down strokes. The indicial formulation is used to calculate the response to harmonic motion, harmonic ramp motion, constant-rate pitching motion and smaller-amplitude harmonic motion. The results show that more accurate results can be obtained when the motion starts from a low angle of attack where hysteresis effect is not important.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Unsteady aerodynamic models for maneuvering aircraft


    Contributors:
    Hu, Chien-Chung (author) / Lan, C. E. (author) / Brandon, Jay (author)


    Publication date :

    1993-01-01


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English




    Unsteady aerodynamic models for maneuvering aircraft

    HU, CHIEN-CHUNG / LAN, C. / BRANDON, JAY | AIAA | 1993


    Unsteady Aerodynamic Models for Maneuvering Aircraft

    Hu, C.-C. / Lan, E. / Brandon, J. et al. | British Library Conference Proceedings | 1993


    Identification of aerodynamic models for maneuvering aircraft

    Chin, Suei / Lan, C. Edward | NTRS | 1990