Meeting Abstract

P3.15  Thursday, Jan. 6  Effect of leg feathers on the gliding performance and aerodynamic stability of a small dinosaur TISBE, A. R.*; GUENTHER-GLEASON, E. ; EVANGELISTA, D. J.; KOEHL, M. A. R.; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley atisbe@berkeley.edu

Discoveries during the last decade of a diversity of feathered dinosaurs from the Cretaceous of China have led to considerable speculation about the roles that the feathers played on these extinct animals. The aerodynamic hypotheses can be tested empirically by measuring defined aspects of the gliding performance of physical models of the fossils in a wind tunnel. Feathers can be added or removed from the models to quantify their effects on aspects of performance such as glide distance, and also the stability and maneuverability that affect a falling animal’s ability to navigate through complex habitats. We focused on Microraptor gui, a cat-sized dromaeosaur that had flight feathers on both its fore and hind limbs and tail. We compared the lift, drag, and side forces, and the pitch, roll, and yaw moments on models with vs. without leg feathers, and we tested the models in different symmetric and asymmetric postures that have been proposed by various researchers. In some cases leg feathers had no effect, and in others they did (e.g. leg feathers reduced drag for some postures at some angles of attack). Therefore, whether or not leg feathers affected gliding, parachuting, or maneuvering performance depended on the posture and orientation of the dinosaur. These results will contribute to our understanding of the role of aerodynamic surfaces aft of a gliding animal’s center of mass.