Wednesday, November 29, 2006



From Wikipedia, the free encyclopedia

which is lifted and propelled by one or more horizontal rotors. Helicopters are classified as rotary-wing aircraft to distinguish them from conventional fixed-wing aircraft. The word helicopter is derived from the Greek words helix (spiral) and pteron (wing). The first functional helicopter was created by Jan Bahyl in year 1901 of the basis of his patent from August 18, 1895. The helicoper was 6,5 m long, weight was 50 kg and it flew 50 cm over ground. On May 5, 1905 he flew up using his petrol-engine helicopter to a height of four meters for over 1500 meters. His attempt was also recorded by the International Airship Organizement Corpis. The first fully-controllable helicopter was the Focke-Wulf Fw 61 made by Heinrich Focke in 1936. The first single-rotor helicopter - the common configuration today - was made by Igor Sikorsky in 1939.

Compared to conventional fixed-wing aircraft, helicopters are much more complex, more expensive to buy and operate, and are more limited in speed, range, and payload. The compensating advantage is maneuverability: helicopters can hover in place, reverse, and above all take off and land vertically. Subject only to refueling facilities and load/altitude limitations, a helicopter can travel to any location, and land anywhere with enough space (approximately twice the area of the rotor disk).

Compared with other vertical lift aircraft like tiltrotors (V-22 Osprey for example) and vectored thrust airplanes (AV-8 Harrier for example), helicopters are very efficient, carrying more than twice the payload, consuming less fuel in hover and costing considerably less to buy and operate. However these other configurations have a much higher cruise speed than a helicopter (270 km/h for a helicopter, 460 km/h for a tiltrotor, 900+ km/h for a vectored thrust airplane).

Helicopter models and identification

In identifying helicopters during flight it is helpful to know that when viewed from below, the rotor of a French, Russian, or Soviet designed helicopter rotates counter-clockwise, whilst that of a helicopter built in Italy, the UK or the USA rotates clockwise.

Further information: List of helicopter models

Some companies, notably Schweizer Aircraft Corporation in the USA, are developing remotely-controlled variants of light helicopters for use in future battlefields. Rotomotion is currently selling a line of small (less than 50 kg) rotorcraft UAVs, including an all electric helicopter.

Hybrid types that combine features of helicopters and fixed wing designs include the experimental Fairey Rotodyne of the 1950s and the Bell Boeing Osprey, which is on order by the U.S. Marine Corps and will be the first mass produced tiltrotor aircraft to enter service.

A helicopter should not be mistaken for an autogyro, which is a predecessor of the helicopter, that gains lift from an unpowered rotor.

Some common nicknames for helicopters are "copter", "chopper", "whirlybird", "windmill", "helo" (common U.S. Navy usage) or "paraffin Budgie" (the latter term being mostly used in the UK offshore oil industry).

Helicopters are useful for landing in tight spaces.

Many companies have helicopters for transport.