Kinematics of Dragonfly ( Sympetrum flaveolum ) Flight

The kinematics of the flapping flight of the dragonfly Sympetrum flaveolum is investigated. The flapping patterns of the hindwing are recorded and studied thoroughly using a high speed video camera with the highest shuttle speed and resolution as reported so far on study of insect flights. The overall results indicate that the flapping pattern of a dragonfly hindwing at the nodus and the pterostigma can be either a simple figure-eight or a double figure-eight, which is a new discovery. The angle of attack and the wing attitude are studied quantitatively. The relative position of the leading edge and trailing edge implies the presence of lift-enhancing mechanisms after stroke reversal. It is also found that the spanwise leading edge spar of a dragonfly wing is not one rigid piece, but two pieces hinged at the nodus with physical constraint of forty degrees. The elastic modulus of the costa of a hindwing is estimated through vibration tests using a vibrometer.