Meeting Abstract
Hummingbirds are capable of a repertoire of aerobatic maneuvers that are unmatchable in both natural and man-made fliers. Within this repertoire, escape maneuvers are arguably the most unique in that they are characterized by rapid and large-angle rotations about all three body axes. This poses challenging flight control and stabilization problems that interest both biologists and engineers. Kinematic analyses show that hummingbirds are able to rapidly change the three degree-of-freedom wing motion on stroke-by-stroke basis, therefore equipped with extraordinary control authorities for flight control. In addition, hummingbirds also flare their tails to the maximum degree through the entire course of the escape maneuver. In this study, we investigate the force production from both wings and tails of hummingbirds from four different species and evaluate their flight stability and performance. It was found that, similar to insect flight, hummingbird flight is inherently unstable; however, a flared tail enhances the flight stability by producing counter torques, especially in hummingbird species with relatively large tails (e.g. magnificent hummingbird). Estimation of mass-specific power suggests that hummingbirds need to at least double their muscle power output in order to accomplish the escape maneuver. The results also suggest potential scaling effect in hummingbird flight, which can only be understood by integrating flight dynamics, muscle performance and neural control.
