Meeting Abstract

21.4  Sunday, Jan. 4  Scaling of passive damping and maneuverability in flying animals HEDRICK, TL*; DENG, X; CHENG, B; University of North Carolina at Chapel Hill; University of Delaware; University of Delaware thedrick@bio.unc.edu

Most analyses of animal locomotion dynamics place stability and maneuverability on opposite poles; factors that enhance capability one are expected to reduce capability in the other. Here we show that flying animals at scales ranging from fruit flies to large birds benefit from substantial damping of angular velocity through a passive aerodynamic mechanism termed flapping counter-torque (FCT). Furthermore, changes to wing kinematics or morphology that enhance FCT are also expected to enhance maneuverability, allowing flying animals to simultaneously specialize in both maneuverability and a form of passive stability, at a predicted cost of increasing the amount of energy required for flight. We demonstrate these effects by developing a simplified analytic model for FCT, then using it to predict the scaling of damping for 4 species: fruit flies (Drosophila melanogaster), hawkmoths (Manduca sexta), hummingbirds (Archilochus colubris), and cockatoos (Eolophus roseicapillus). These predictions were then compared to yaw turns or perturbations recorded from each species. Turn dynamics were consistent with the FCT predictions. Finally, we show that this wide range of flying animals experiences similar passive damping on a per-wingbeat timescale, suggesting that all flying animals may make substantial use of passive mechanisms when reducing angular velocity following a maneuver or when recovering from an unexpected perturbation.