“Dragonflies are supremely efficient in all areas of flying,” said UniSA professor Javaan Chahl. “They can turn quickly at high speeds and take off while carrying more than three times their own body weight. They are also one of nature’s most effective predators, targeting, chasing and capturing their prey with a 95% success rate.”
The wings are long, light (2% of the insect’s weight) and rigid, with a high lift-to-drag ratio fir superior aerodynamic performance.
Intact dragonflies are notoriously difficult to capture, said the university, leading the team to mine other resources – including developed an optical technique to photograph the wing geometry of un-touchable museum specimens from outside their display cases, from which 3D models of the wings of 75 different dragonfly species were reconstructed.
Combined with earlier research and mathematical modelling, many subtleties were discovered: such as the way corrugations in the thin wings improve wing stiffness, but also maintain airflow at higher angles of attack than would be possible with a flat wing; and the effect of the abdomen: “Their long abdomen, which makes up about 35% of their body weight, has also evolved to serve many purposes,” said Chahl. It houses the digestive tract, is involved in reproduction, and the abdomen plays a crucial role in their flying ability – it helps with balance, stability and manoeuvrability.”
The researchers believe a dragonfly lookalike drone could do many jobs, including collecting and delivering awkward, unbalanced loads, safely operating near people, exploring delicate natural environments and executing long surveillance missions.
The work is published in the journal Drones as ‘Biomimetic drones inspired by dragonflies will require a systems-based approach and insights from biology‘. Part a review of existing research, part original research, and part mathematical analysis, the paper is extensive, clearly written and can be accessed without payment.