Inspired by Feathers, New Wing Design Takes Flight

To better equip unmanned aircraft for turbulence, a GW professor is turning to the experts: birds.

More than a century after Wilbur and Orville Wright launched the era of human flight, a GW researcher is going back to the original flyers—birds—for inspiration in designing the next generation of unmanned aircraft.

Military drones and other unmanned aircraft fly much closer to the ground than commercial jets, where the wind has more surfaces to interact with and turbulence is far less predictable, said Adam Wickenheiser, a professor in the Department of Mechanical and Aerospace Engineering.

While commercial aircraft try to sense and dodge turbulence, for the low-flying unmanned aircraft “in many situations you have no choice but to run right into it.”

Birds are in a similar bind, with solutions hammered out by evolution. Now Dr. Wickenheiser is hoping to borrow from their biological blueprints to create a feather-inspired wing that could allow aircraft to run more efficiently and with tighter control.

The idea is to attempt to “mimic some of the benefits but not necessarily mimic the exact same form and structure,” he said. Bird bodies, though primed for flight, don’t suit all of mankind’s aerial needs.

“There are some things that we can do better,” said Dr. Wickenheiser. “No bird can lift tens of thousands of pounds and fly it across the country in six hours.”

Dr. Wickenheiser, who is among the engineers expected to be moving into GW’s new Science and Engineering Hall, is working this summer from Eglin Air Force Base, in Florida, as part of the U.S. Air Force’s Summer Faculty Fellowship Program.

Rather than using a few, large mechanical control elements—such as flaps on the wings and tail—to steer, Dr. Wickenheiser plans to use smaller panels in greater numbers. The panels will move in clusters that emulate a feathered wing.

A bird in flight “isn’t actively saying, ‘OK, Feather 1 go up, Feather 2 go down.’ It’s kind of all moving together fluidly and continuously,” he said.

Birds splay apart their wing feathers to let sudden gusts of wind pass through. It's an ability Dr. Wickenheiser is hoping to recreate in his design for the wings of unmanned aircraft. (Images courtesy Adam Wickenheiser)

The result, he thinks, will be a nimble wing that can have its “feathers” flared to brake, or splayed apart to allow a sudden gust to pass through, and be capable of maneuvering through turbulence to give sensitive onboard cameras and other equipment a smoother ride.

In order to do that, the concept involves shifting some of the aircraft’s brains—sensors and controls—into the wings, allowing the response to be local and faster; more predictive and less reactionary.

Instead of responding only after turbulence is felt centrally, sensors in the wings could detect a change in air pressure or wind direction and the wings could begin adjusting in anticipation of turbulence, relying on a catalog of pre-programmed, local responses.

Dr. Wickenheiser equates that to the fluidity of thought and movement in animals, in which some responses are instinctive. “If I step on an uneven piece of ground, I don’t really think about it. I just adjust automatically and walk over it.”

The main onboard computer then is freed to work on overarching functions, like maintaining course and determining whether the wings should be configured for stability or maneuverability.

The added control could mean energy savings—if an aircraft handles turbulence better, it will be thrown off-course less—and further testing could find that the wing design also offers greater agility, such as a tighter turning radius, said Dr. Wickenheiser.

This summer at the Air Force base, Dr. Wickenheiser is running computer simulations and building the catalog of responses to possible scenarios, like gusts of various strengths hitting the aircraft from all directions.

He and a graduate student, Chris Blower, also are planning experiments for later this summer that will pit a model section of the wing design against real gusts in the small-scale wind tunnel at GW’s Virginia Science and Technology Campus, in Ashburn.

The smarter wing design, Dr. Wickenheiser said, could be a step toward “self-healing or more modular” robotics that also is inspired by biology. If a bird loses a feather “it’s not the end of the world,” he said, “whereas if a chunk comes off of an aircraft, it basically spells disaster.”

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