Saturday, September 4, 2010

Fastest helicopter in the world

Found on IEEE Spectrum:

If you try to get a helicopter to go fast, the blades start to mess with the lift of the helicopter. On a moving helicopter, when the blades swing around forwards, they experience faster air than when they swing backwards. It's like throwing a baseball on a moving car. If you throw forwards, the baseball will go faster and experience all that wind hitting it; if you throw backwards, it's moving more with the wind and experiences less. This becomes dramatic as the helicopter moves faster and the blades move even faster to get it to do so. Quote from article: "[when the helicopter is moving] 300 km/h, the wind on the advancing side would reach 1100 km/h, while the wind on the opposite side would be 500 km/h." There comes a point where the helicopter can't balance this difference in lift and can't go faster.

Sikorsky's X2 has been designed with two sets of rotors that spin in opposite directions, countering this problems. It has broken the record of 400 km/h at a speed of 435 km/h (248.5 mph and 270.3 mph respectively). (They still need to do a couple things with the record keeper organization to make it official).

If you want to read more, the article is quite long, has lots of details, and a bunch of history.

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