Airplane

, also called AEROPLANE, or PLANE, any of a class of fixed-wing aircraft that is heavier than air, propelled by a screw propeller or a high-velocity jet, and supported by the dynamic reaction of theair against its wings. Two kinds of aircraft without fixed wings that are classified as airplanes are the STOL airplane and the VTOL airplane. A brief treatment of airplanes follows.

For treatmentof historical aspects, see Transportation; for manufacturing technology, see Industries, Manufacturing; for military aspects, see War, The Technology of.

The essential components of an airplane area wing system to sustain it in flight, tail surfaces to stabilize the wing, movable surfaces (ailerons, elevators, and rudders) to control the attitude of the machine in flight, and a power plant toprovide the thrust to push the craft through the air.

An enclosed body (fuselage) houses the crew, passengers, and cargo, as well as the controls and instruments used by the navigator. An airplanealso requires a support system (such as wheels or pontoons) when it is at rest on a surface and during takeoff and landing.

Most airplanes in use today are monoplanes (i.e., aircraft with a singlepair of wings). They are termed high-wing when the wing is attached at the top of the fuselage, midwing when it extends from or near the centre of fuselage section, and low-wing when the wingstructure fastens to the fuselage structure at the bottom. The multiplane with two or more horizontal wing systems, one above the other, connected by a series of struts and wires, has virtually disappeared.The few biplanes still in service are used mainly for sport flying or for agricultural crop dusting. Monoplanes may be characterized by the planform (top view) of their wings, which may berectangular, tapered, swept-back, or delta. A so-called variable-geometry concept incorporating adjustable sweepback is a compromise to obtain good high- and low-speed characteristics from the same wing....