vertical takeoff and landing aircraft
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vertical takeoff and landing aircraft(VTOL), craft capable of rising and descending vertically from and to the ground, thus requiring no runway. While a balloonballoon,
lighter-than-air craft without a propulsion system, lifted by inflation of one or more containers with a gas lighter than air or with heated air. During flight, altitude may be gained by discarding ballast (e.g.
..... Click the link for more information. or an airshipairship,
an aircraft that consists of a cigar-shaped gas bag, or envelope, filled with a lighter-than-air gas to provide lift, a propulsion system, a steering mechanism, and a gondola accommodating passengers, crew, and cargo.
..... Click the link for more information. has obvious VTOL capability, both are very inefficient at moving parallel to the earth's surface. The autogiroautogiro
, type of aircraft supported in the air by a horizontally mounted airfoil similar to that of a helicopter but unpowered. Invented by the Spaniard Juan de la Cierva, it was first flown successfully in Jan., 1923, in Spain.
..... Click the link for more information. and the helicopterhelicopter,
type of aircraft in which lift is obtained by means of one or more power-driven horizontal propellers called rotors. When the rotor of a helicopter turns it produces reaction torque which tends to make the craft spin also.
..... Click the link for more information. offer some improvement in this respect, but still have very limited performance. A large number of VTOL designs have been produced and tried. The pogo-stick, or tail-sitting, type was similar in appearance to a conventional airplane except for a special tail on which it took off and landed. This type was abandoned, partly because of the difficulty in maintaining fine control when its fuselage was positioned vertically, e.g., during a landing. Convertiplanes are VTOL craft that can fly horizontally with the same effectiveness as a conventional airplane. Some convertiplanes are conventional-looking aircraft that can tilt their rotors, or oversize propellors, so that the rotors' axes are vertical during takeoff and landing and are horizontal during forward flight. The best-known such tilt-rotor aircraft is the V-22 Osprey, which first flew in 1989. The Harrier is a jet fighter convertiplane that uses vanes to direct the thrust of its engine upward or forward and is capable of flight at approximately the speed of sound; it proved its ability to control a battlefield despite the absence of airports and runways during the 1982 Falklands conflict.
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