Coaxial Cruising

Pretty cool video here of Sikorsky's latest whirlybird, the X2 demonstrator, which has hit 262 knots, or 300 miles an hour, a record for a helo. Nice acceleration too. The coaxial rotors spin in opposite directions to keep the aircraft from stalling at high speeds. It's no easy feat, as this article describes.

http://www.youtube.com/watch?v=gK7ktLXhq88