United Tech says tests world's fastest helicopter

BOSTON, Aug 27 (Reuters) - Diversified U.S. manufacturer United Technologies Corp, the world's second-largest helicopter maker, conducted the first test flight on Wednesday of what it called the world's fastest helicopter.

The prototype X2 aircraft has an estimated cruising speed of 250 knots, or 288 miles per hour (464 kmph), and has been in development since June 2005, United Tech's Sikorsky unit said.

The fastest helicopters on the market today top out at about 180 knots, or 207 miles per hour (333 kmph), according to Sikorsky officials. Textron Inc's V-22 Osprey tilt- rotor aircraft, which takes off and lands like a helicopter but flies like an airplane, cruises at about 275 knots, or 316 miles per hour (509 kmph).

In its first 30-minute test flight in Horseheads, New York, about 200 miles (320 km) northwest of New York City, the pilot did not attempt to bring the aircraft to its top speed, keeping it to 20 knots, or 23 miles per hour (37 kmph). It is common industry practice to test new aircraft at slower speeds first, said Jim Kagdis, the program manager over the X2 at Sikorsky. He said the company planned to test the aircraft's top speed by next year.

Kagdis estimated it could be another five to eight years before the aircraft is commercially available.

The X2 helicopter features two main rotors atop the cabin, which spin in opposite directions. That both neutralizes the spinning force applied to a traditional single-main-rotor helicopter and provides a speed boost.

Using the two opposing rotors also eliminates the need for the sideways tail rotor used to stabilize traditional helicopters. Instead of that sideways tail rotor, Sikorsky has added a third, backwards-facing tail rotor that provides additional speed.

The world's largest helicopter maker is Eurocopter, a unit of EADS NV. Other helicopter makers include Italy's AgustaWestland, a unit of defense company Finmeccanica SpA, Boeing Co and Textron's Bell unit.

http://www.guardian.co.uk/business/feedarticle/7756815

Fonte: Flight Safety Information 29/08/2008.