The aerodynamic performance of the feathertail glider, Acrobates pygmaeus (Marsupialia: Acrobatidae)

摘要

Photographic and videographic investigations of the aerodynamic performance of four captive adult Acrobates pygmeus are described. During short (1-4 m) glides, steep angles of descent (>45 degrees) and large angles of attack (up to 50 degrees) were used mid-flight, and the possums failed to achieve steady velocities. During longer (>10 m) glides steady velocities of 5.3-7.5 m s(-1) were achieved, and glide angles of 21-42 degrees and angles of attack between 36 degrees and 45 degrees were used. The best (lowest) glide angles used at steady velocity were similar to those documented in sugar gliders, but involved lower air speeds. During steady gliding the forelimbs of Acrobates assumed an 'elbows-out' disposition similar to that of Petauroides volans, and unlike that of petaurid gliders. A glide polar for Acrobates shows that it uses lower air speeds and higher sinking speeds than other gliding animals for which polars are available (several birds and one bat). Few data on the radius of turn and sinking speed were obtained; nevertheless, in accord with theory, sinking speeds were higher during tighter turns. During flight the feather-like tail was used to generate pitching movements and adjust the angle of attack and hence glide angle. However, the control of turns seems to be achieved primarily through limb adjustments.C1 Pridmore, Peter A.; La Trobe Univ, Dept Environm Management and Ecol, Albury Wodonga Campus,POB 821, Wodonga, Vic 3689, AustraliaSC Physiology