The forerunner of the fixed-wing aircraft is the kite. Rocket-powered missiles that obtain aerodynamic lift at very high speed due to airflow over their bodies are a marginal case.Īn Airbus A380, the world's largest passenger airliner V/STOL aircraft, such as the Harrier Jump Jet and Lockheed Martin F-35B take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight.Ī pure rocket is not usually regarded as an aerodyne because it does not depend on the air for its lift (and can even fly into space) however, many aerodynamic lift vehicles have been powered or assisted by rocket motors. With powered lift, the aircraft directs its engine thrust vertically downward. A kite is tethered to the ground and relies on the speed of the wind over its wings, which may be flexible or rigid, fixed, or rotary. A flexible wing is a wing made of fabric or thin sheet material, often stretched over a rigid frame. To fly, air must flow over the wing and generate lift. A wing is a flat, horizontal surface, usually shaped in cross-section as an aerofoil.
There are two ways to produce dynamic upthrust - aerodynamic lift, and powered lift in the form of engine thrust.Īerodynamic lift involving wings is the most common, with fixed-wing aircraft being kept in the air by the forward movement of wings, and rotorcraft by spinning wing-shaped rotors sometimes called rotary wings. This dynamic movement through the air is the origin of the term. Heavier-than-air aircraft, such as airplanes, must find some way to push air or gas downwards so that a reaction occurs (by Newton's laws of motion) to push the aircraft upwards. In modern times, any small dirigible or airship is called a blimp, though a blimp may be unpowered as well as powered. The nickname blimp was adopted along with the shape. During World War II, this shape was widely adopted for tethered balloons in windy weather, this both reduces the strain on the tether and stabilizes the balloon. Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. Sometimes this term is applied only to non-rigid balloons, and sometimes dirigible balloon is regarded as the definition of an airship (which may then be rigid or non-rigid). Nowadays a "balloon" is an unpowered aerostat and an "airship" is a powered one.Ī powered, steerable aerostat is called a dirigible. Then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, so "airship" came to be synonymous with these aircraft.
#XAIRCRAFT FLIGHT CONTROL SYSTEM SKIN#
Huge powered aerostats, characterized by a rigid outer framework and separate aerodynamic skin surrounding the gas bags, were produced, the Zeppelins being the largest and most famous. The advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. In 1919, Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "Air yachts." In the 1930s, large intercontinental flying boats were also sometimes referred to as "ships of the air" or "flying-ships". Airship USS Akron over Manhattan in the 1930sĪ balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs - usually fixed-wing.