Hummingbirds Inspire Drone Design

(Source: http://www.audubon.org)  

It’s hard to get a good look at hummingbirds’ wings, given that they’re normally beating so fast they’re a blur. But compared to wings in the human-made world—think helicopters—the birds’ feathered appendages are relatively short and stubby, characteristics that help these expert fliers hover. Now researchers are thinking that if short wings help hummingbirds, they might help drones become more agile, too.

Researchers from Stanford University attached carbon fibre models of different-sized wings (some shorter and fatter; some longer and thinner) to a small hummingbird-inspired flying device. They found that wings 4 times as long as they were wide were the best at generating the small tornado of air needed to keep the bird hovering when taking sharp turns. This is short compared to helicopter wings (which tend to be 10 times as long as they are wide), but comparable to the flappers on bats, other birds, and insects.

Hummingbirds and insects have more than wing length in common. A paper last fall showed that hummingbird flight technique is more similar to that of insects than other birds: They generate lift on both the upstroke and downstroke.

The research into hummingbird flight could help researchers determine the right wing size to help tiny flying drones be more efficient. “If you operate at low angle of attack, you want to use a super-efficient helicopter blade,” says David Lentink, lead researcher of the new work, in a statement, “but if you need to avoid stall at high angles, you better select a stubby hummingbird wing.”

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