Want to see the future of flight? Then visit the beach.
Scientists have found that airplane wings shaped similarly to those of some seagulls may reduce drag during flight.
Drag reduction saves fuel, explains Barry Lazos, an aeronautics research engineer at the NASA Langley Research Center in Hampton, Virginia.
"We can reduce drag [with existing technology], but many techniques are often costly and impractical," he said. "Our idea was to look to nature for feasible techniques that might provide significant drag reduction."
He and his colleagues studied creatures that propel themselves through air and water, which are both fluids, for inspiration. (Related: "Quieter Aircraft Takes Cues From Birds, NASA Expert Says" [August 22, 2006].)
"If we saw an interesting characteristic, say a wing shape or a perturbation at a certain location, then we might consider using that in a wind-tunnel test," Lazos said.
The researcher said the approach was a "shot in the dark" because the team did not know beforehand how fluids would flow around the shapes modeled and tested in the wind tunnel.
"The idea was to determine if we can get a drag benefit and then study the flow characteristics to see if we can make further improvements," he added.
Seagull Breakthrough
The wing designs tested included two that were inspired by seagull wings, one with features found in the back and tail fins of great white sharks, and a wing with features found on the pectoral fins of humpback whales.
The wing inspired by a seagull in gliding flight proved to have the greatest drag reduction—a 4 percent improvement over the theoretically best conventional aircraft wing.
The wing is highly cambered in the span-wise direction—in other words, there's a bend along the length of the wing and the tips point down (see image at left), says Ken Visser, a research collaborator and associate professor of aeronautical engineering at Clarkson University in Potsdam, New York.
|
SOURCES AND RELATED WEB SITES
|
