Dragonfly Flight : II. Velocities, Accelerations and Kinematics of Flapping Flight

TLDR

The study describes wingtip kinematics of dragonfly and damselfly flapping flight. The authors filmed free flapping flight of Sympetrum sanguineum and Calopteryx splendens at 3000 fps in a large enclosure. The damselfly flew at half the dragonfly’s wingbeat frequency, could perform clap‑and‑fling with force proportional to wing proximity, exhibited greater stroke‑plane angle variation, and while both species aligned stroke planes normal to thrust, only the dragonfly’s body alignment correlated with thrust; overall dragonfly velocities and accelerations were higher, but damselfly non‑dimensional velocities and accelerations were greater.

Abstract

The free flapping flight of the dragonfly Sympetrum sanguineum and the damselfly Calopteryx splendens was filmed in a large flight enclosure at 3000 frames s-1. The wingtip kinematics are described for these flights. Despite the two species being similar in size, the damselfly flew with wingbeat frequencies half those of the dragonfly. The damselfly could perform a clap and fling, and the proximity to which the wings approached each other during this manoeuvre correlated with the total force produced during the wingstroke. The dragonfly beat its wings with a set inclination of the stroke planes with respect to the londitudinal body axis; the damselfly, in contrast, showed a greater variation in this angle. Both species aligned their stroke planes to be nearly normal to the direction of the resultant force, the thrust. In order to achieve this, the dragonfly body alignment correlated with the direction of thrust. However, the damselfly body alignment was independent of the thrust direction. Velocities and accelerations were greater for the dragonfly than for the damselfly. However, non-dimensional velocities and accelerations normalised by the wingbeat periods were greater for the damselfly.