London, June 25 : Aerospace engineers have determined that the corrugated wings on a dragonfly have an aerodynamic function, which gave the insects a much greater lift than expected in a gliding flight.
According to a report in New Scientist, though the dragonfly Aeschna cyanea can glide for up to 30 seconds without so much as a wingbeat, yet its wings look nothing like the supposedly ideal streamlined, cambered wings of an aeroplane.
Instead, the wing surfaces are highly corrugated, with pleats that stiffen them against bending across their span.
But until now, no one could say for sure whether those pleats have any aerodynamic function, too.
To find out, aerospace engineers Abel Vargas and colleagues at The George Washington University in Washington DC flew detailed virtual models of A. cyanea's wings in a fluid dynamics simulator.
They found that the pleats gave the wings much greater lift than they expected in gliding flight, matching and sometimes bettering that of a similarly sized streamlined wing.
This is because air circulates in the cavities between pleats, creating areas of very low drag that aid the lift-generating airflow across the wing.
According to the researchers, palm-sized reconnaissance aircraft could adopt the design of such pleated wings to gain both strength and extra lift.