https://www.youtube.com/watch?v=WaQB16ZaNI4

What is the fastest RC aircraft? Amazingly, gliders. The non-powered planes can, in skilled hands, whip up a speed of over 300 mph from a relatively slow wind. That's a velocity of around 8x the speed of the air driving it.

It's called Dynamic Soaring, or DS, and it requires some specific land and weather conditions, experience and the cojones to slice your precious RC plane through extreme wind shears. If you have a long hill or ridge and the wind is hitting it at a right angle, the air that moves over the top causes an eddy on the leeward side, a steady, spinning whirlpool of air underneath the wind shooting over the ridge.

If you can hit it right, you can power the glider over the ridge and then dip it down into the torrent of air running in the opposite direction. Flip the plane 180º, over and over, and you'll build up speed. The video above shows a glider clocking an astonishing 392mph from a wind gusting to just 45mph. Think of it as somewhere between surfing a big wave and pumping a skateboard around a half-pipe.

Of course, it's not easy. Bill Patterson, author of the rather splendid site DS Zone, was flying at a relatively sedentary 150mph and "made the mistake of making too large of a correction while the plane was still in the boundary layer at the bottom, and the v-tail blew off." Go take a look at both his very clear Flash animation which explains just how this all works, and catch some of the videos of these gliders in action. Even watching a little thumbnail QuickTime video will tighten your stomach in the same way as staring down a high, steep mountain precipice. As Wired.com editor Dylan Tweney noted when he sent the link, "This is extremely cool."

Dynamic Soaring [DS Zone. Thanks, Paul!]

New Dynamic Soaring World Record – 392mph [YouTube]