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ambience: Birds
From Daedalus to DaVinci and beyond, mankind has dreamed of soaring like a bird. Airplanes and gliders fly, of course but soaring is a communion with the wind. I’m Jim Metzner, and this is the Pulse of the Planet.
“I’ve watched many birds rise in thermals. I love the way that they seem to do it so effortlessly and climb without using any energy at all.”
Michael Allen is an aerospace engineer at Dryden Flight Research Center who’s been developing a computer program that, in effect, teaches lightweight motorized unmanned air vehicles to soar, just like a bird.
“This airplane was named after a bird. It’s called the cloud swift. It’s a strange bird because it stays up in thermals most of day. It rarely comes down. So it’s a very elusive bird.”
Birds soar by riding the currents of air called thermals.
“A thermal forms when the sun heats the ground and the air near the ground becomes hot. Hot air rises because of buoyancy similar to a hot air balloon. So, eventually that hot air breaks free from the ground and begins to rise. If a plane can stay in that bubble of air it will rise with the air.”
And with the help of a computer, an unmanned air vehicle can be taught to do just that.
“The computer takes sensed pressures from the aircraft and accelerations things that it measures about what the airplane is doing, and then it calculates what the aircraft should do next; how it should turn and how it should respond to stay in the lift. I think a lot of it is a mimic of what birds do. Of course, birds are better at it, but we can take a lot of lessons from their techniques for this project.”
An unmanned air vehicle that can stay aloft longer by soaring is useful in a number of ways. We’ll hear more in future programs. Pulse of the Planet is made possible by the National Science Foundation, with additional support from NASA. I’m Jim Metzner.
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