The Shape of Wings to Come

摘要

It seems ludicrous to think of an F-16 fighter jet as crude. But spend a few hours at the beach watching the lowly, scavenging seagull as it swoops over the sand, eyes a leftover french fry, pauses a moment, drops earthward, lands, grabs the morsel, and takes wing again. Not an aircraft in the world can match that performance. "And the seagull doesn't even use its tail during steady flight!" says Barry Lazos, a fluid aerodynamicist at NASA's Langley Research Center in Hampton, Virginia. "When a seagull takes off, lands, or makes sharp turns, it makes dramatic movements with its wings, but during steady flight it turns with subtle wing changes mostly at the wing tips. It doesn't even have a rudder," he says, shaking his head in amazement. "How does it change its direction? We don't know. In all my study I've found nothing that tells me how birds maneuver without their tails."