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Heavier than air Heavier than air aircraft, or aerodynes, include autogyros, gyrodynes, helicopters, powered lifts, and conventional fixed-wing aircraft (aeroplanes). Fixed-wing aircraft generally use an internal-combustion engine in the form of a piston engine (with a propeller) or a turbine engine (jet or turboprop), to provide thrust that moves the craft forward through the air. The movement of air over the wings produces lift that causes the aircraft to fly. Exceptions include gliders which have no engines and gain their thrust, initially, from winches or tugs and then from gravity and thermal currents. For a glider to maintain its forward speed it must descend in relation to the air (but not necessarily in relation to the ground). |
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| Helicopters and autogyros use a spinning rotor (a rotary wing) to provide lift; helicopters also use the rotor to provide thrust. Gyrodynes are aircraft intermediate between helicopters and autogyros, whose rotor is sometimes powered (often by a jet at its tips) but which do not have a tail rotor. | |||||||
| Heliplanes are combination aircraft with both a rotor and wings; they can take off and land vertically, and hover, like a helicopter, but use their wings for high speed flight. The abbreviation "VTOL" is applied to aircraft that can take off and land vertically. "STOL" stands for Short Take Off and Landing. Lighter than air Lighter than air aerostats: balloons and airships. Aerostats use buoyancy to float in the air in much the same manner as ships float on the water. In particular, these aircraft use a relatively low density gas such as helium, hydrogen or heated air, to displace the air around the craft. The distinction between a balloon and an airship is that an airship has some means of controlling both its forward motion and steering itself, while balloons are carried along with the wind. |
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| By use The major distinction in aircraft usage is between military aviation, which includes all uses of aircraft for military purposes (such as combat, patrolling, search and rescue, reconnaissance, transport, and training), and civil aviation, which includes all uses of aircraft for non-military purposes. Military aircraft , Civilian aircraft |
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credit : http://en.wikipedia.org/wiki/Aircraft
