Airplane, engine-driven vehicle that can fly through the air supported by the action of air against its wings. Airplanes are heavier than air, in contrast to vehicles such as balloons and airships, which are lighter than air. Airplanes also differ from other heavier-than-air craft, such as helicopters, because they have rigid wings; control surfaces, such as movable parts of the wings and tail, which make it possible to guide their flight; and power plants, or special engines that permit level or climbing flight. Airplanes fly by employing Bernoulli’s principle to increase lift, air pressure upward acting at the wings of the planes. The weight is circumvented by this lift to help the plane go upward.
Airplanes are adapted to specialized uses. Today there are land planes (aircraft that take off from and land on the ground), seaplanes (aircraft that take off from and land on water), amphibians (aircraft that can operate on both land and sea), and airplanes that can leave the ground using the jet thrust of their engines or rotors (rotating wings) and then switch to wing-borne flight. Airplanes also played a major role during wars and military expeditions as dominating air space is a strategic advantage that any faction should consider to have. With the advent of stealth planes (invisible to radars), airplanes can even drop an atomic bomb in a city without the military security of that country dumbfounded on what hit them.
Posted 2011-01-24 and updated on Jan 24, 2011 2:26pm by crisd