Symmetric steady flapping flight of bird-scale aircraft, using bifurcation and continuation method

The performance and the stability of a flapping wing aircraft in symmetric, steady flight are analysed for a generic model comparable to mid-sized birds. Limit cycles corresponding to symmetric flight are computed using numerical continuation as functions of the elevator deflection and the flapping frequency. Level flight is seen to occur in a small range of frequencies which is almost independent of the elevator deflection and the wing feathering angle profile. Floquet multipliers computed during the continuation process are used to derive the modal decomposition of the dynamics. Bifurcations in the state-parameter space help identify some typical mechanisms for the onset of instability in the individual modes.