An aircraft or aerial vehicle is a vehicle that can fly by gaining support from the air. It counters the force of gravity by using either static lift or the dynamic lift of an airfoil, or, in a few cases, direct downward thrust from its engines. Common examples of aircraft include airplanes, drones, rotorcraft (including helicopters), airships (including blimps), gliders, paramotors, and hot air balloons. Part 1 (Definitions and Abbreviations) of Subchapter A of Chapter I of Title 14 of the U. S. Code of Federal Regulations states that aircraft "means a device that is used or intended to be used for flight in the air".
The human activity that surrounds aircraft is called aviation. The science of aviation includes the designing and building of aircraft, which is called aeronautics. A crewed aircraft is flown by an onboard pilot, whereas an unmanned aerial vehicle may be remotely controlled or autonomous, controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, propulsion (if any), usage and others.
History
The history of aviation spans over two millennia, from the earliest innovations like kites and attempts at tower jumping to supersonic and hypersonic flight in powered, heavier-than-air jet aircraft. Kite flying in China, dating back several hundred years BC, is considered the earliest example of man-made flight. In the 15th century, Leonardo da Vinci created flying machine designs incorporating aeronautical concepts, but they were unworkable due to the limitations of contemporary knowledge.
In the late 18th century, the Montgolfier brothers invented the hot-air balloon which soon led to manned flights. At almost the same time, the discovery of hydrogen gas led to the invention of the hydrogen balloon. Various theories in mechanics by physicists during the same period, such as fluid dynamics and Newton's laws of motion, led to the development of modern aerodynamics; most notably by Sir George Cayley. Balloons, both free-flying and tethered, began to be used for military purposes from the end of the 18th century, with France establishing balloon companies during the French Revolution.Hallion (2003)
In the 19th century, especially the second half, experiments with gliders provided the basis for learning the dynamics of winged aircraft; most notably by Cayley, Otto Lilienthal, and Octave Chanute. By the early 20th century, advances in engine technology and aerodynamics made controlled, powered, manned heavier-than-air flight possible for the first time. In 1903, following their pioneering research and experiments with wing design and aircraft control, the Wright brothers successfully incorporated all of the required elements to create and fly the first airplane."Flying through the ages" BBC News. Retrieved 2024-10-18. In 1906 Charles Frederick Page was granted the first U.S. patent for an aircraft. The basic configuration with its characteristic cruciform tail was established by 1909, followed by rapid design and performance improvements aided by the development of more powerful engines.
The first vessels of the air were the rigid steerable balloons pioneered by Ferdinand von Zeppelin that became synonymous with airships and dominated long-distance flight until the 1930s, when large flying boats became popular for trans-oceanic routes. After World War II, the flying boats were in turn replaced by airplanes operating from land, made far more capable first by improved propeller engines, then by jet engines, which revolutionized both civilian air travel and military aviation.
In the latter half of the 20th century, the development of digital electronics led to major advances in flight instrumentation and "fly-by-wire" systems. The 21st century has seen the widespread use of pilotless drones for military, commercial, and recreational purposes. With computerized controls, inherently unstable aircraft designs, such as flying wings, have also become practical.
Methods of lift Lighter-than-air
Lighter-than-air aircraft or aerostats use buoyancy to float in the air in much the same way that ships float on the water. They are characterized by one or more large cells or canopies, filled with a lifting gas such as helium, hydrogen or hot air, which is less dense than the surrounding air. Other gases lighter than air also theoretically work; however, such gases also need to be safe for human use (non-flammable, non-toxic).
Small hot-air balloons, called sky lanterns, were first invented in ancient China prior to the 3rd century BC and used primarily in cultural celebrations, although they also had military purposes. They, along with kites, were two forms of unmanned aircraft that originated from China. Kites were also used in the military, but unlike sky lanterns, their flight is caused by the differences in air pressure beneath and above the kite.
A balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs—usually fixed-wing.US patent 467069 "Air-ship" referring to a compound aerostat/rotorcraft.Ezekiel Airship (1902) wright-brothers.org altereddimensions.net "airship,"—referring to an HTA aeroplane.The Bridgeport Herald, August 18, 1901 —"air ship" referring to Whitehead's aeroplane.Cooley Airship of 1910, also called the Cooley monoplane.—a heavier-than-air monoplane.Frater, A.; The Balloon Factory, Picador (2009), p. 163. Wright brothers' "airship."George Griffith, The angel of the Revolution, 1893 —"air-ship", "vessel" referring to a VTOL compound rotorcraft (not clear from the reference if it might be an aerostat hybrid.) In 1919, Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "Air yachts."Auckland Star, 24 February 1919 "Ships of the air," "Air yachts"—passenger landplanes large and small In the 1930s, large intercontinental flying boats were also sometimes referred to as "ships of the air" or "flying-ships".The Sydney Morning Herald, Monday 11 April 1938—"ship of the airs," "flying-ship," referring to a large flying-boat.Smithsonian, America by air "Ships of the Air" referring to Pan Am's Boeing Clipper flying-boat fleet.
Lighter-than-air aircraft don't typically require a pilot's license in the United States. In most countries in Europe, standards for flying Lighter-than-air aircraft tend to be stricter compared to the United States.Balloon and other aircraft certifications or regulations. https://www.easa.europa.eu/en/regulations#regulations-balloons
Heavier-than-air Heavier-than-air aircraft or aerodynes are denser than air and thus must find some way to obtain enough lift that can overcome the aircraft's weight. There are two ways to produce dynamic upthrust—aerodynamic lift by having air flowing past an aerofoil (such dynamic interaction of aerofoils with air is the origin of the term "aerodyne"), or powered lift in the form of reactional lift from downward engine thrust.
Aerodynamic lift involving wings is the most common, and can be achieved via two methods. Fixed-wing aircraft (airplanes and gliders) achieve airflow past the wings by having the entire aircraft moving forward through the air, while rotorcraft (helicopters and autogyros) do so by having mobile, elongated wings spinning rapidly around a mast in an assembly known as the rotor.
Fixed-wing aircraft
Gliders were one of the first forms of a fixed-wing aircraft. They are a special type of aircraft that doesn't require an engine. The first person to successfully build a human-carrying glider was George Cayley, who also was the first to discover the four major aerodynamic forces. The first powered aircraft (Airplane) was invented by Wilbur and Orville Wright.
Rotorcraft
A rotary-wing aircraft, rotorwing aircraft or rotorcraft is a heavier-than-air aircraft with rotary wings that spin around a vertical mast to generate lift. The assembly of several rotor blades mounted on a single mast is referred to as a rotor. The International Civil Aviation Organization (ICAO) defines a rotorcraft as "supported in flight by the reactions of the air on one or more rotors"."ICAO Annex 7." Retrieved on 30 September 2009.
Rotorcraft generally include aircraft where one or more rotors provide lift throughout the entire flight, such as helicopters, gyroplanes, autogyros, and gyrodynes. Compound rotorcraft augment the rotor with additional thrust engines, propellers, or static lifting surfaces. Some types, such as helicopters, are capable of vertical takeoff and landing. An aircraft that uses rotor lift for vertical flight but changes to solely fixed-wing lift in horizontal flight is not a rotorcraft but a convertiplane.
Other methods of lift
A lifting body is an aircraft that produces lift through the shape of its body, rather than its wings or rotors, like conventional aircraft. Lifting bodies were first used experimentally by NASA in the 1960s and 1970s, but the idea was conceived in the 1950s. A powered lift aircraft is one which has the capability of vertical takeoff and landing. These aircraft must transition from vertical to lateral movement, which is considered the most dangerous phase of a flight. Classes of powered lift types include VTOL jet aircraft (such as the Harrier jump jet) and tiltrotors, such as the Bell Boeing V-22 Osprey, among others. An ornithopter is an aircraft that produces lift through the movement of its wings, akin to how a bird flies.
Size and speed extremes Size The largest aircraft by dimensions and volume (as of 2016) is the long British Airlander 10, a hybrid blimp, with helicopter and fixed-wing features, and reportedly capable of speeds up to , and an airborne endurance of two weeks with a payload of up to ."World's largest aircraft the Airlander makes maiden flight in UK," 16 August 2016, London 'Daily Telegraph' via Telegraph.co.uk. Retrieved 22 November 2016."Airlander 10, the world's largest aircraft, takes off for the first time," 19 August 2016, CBS News (TV) retrieved 22 November 2016.Kottasova, Ivana "The world's largest aircraft crashes after 2nd test flight" , 24 August 2016, CNN Tech on CNN, the Cable News Network. Retrieved 22 November 2016.
The largest aircraft by weight and largest regular fixed-wing aircraft ever built, , was the Antonov An-225 Mriya. That Soviet-built (Ukrainian SSR) six-engine transport of the 1980s was long, with an wingspan. It holds the world payload record, after transporting of goods, and has flown loads commercially. With a maximum loaded weight of , it was also the heaviest aircraft built to date. It could cruise at ."Watch the world's biggest plane land in Australia," 16 May 2016, Fox News. Retrieved 22 November 2016.Lewis, Danny, "The World's Largest Aircraft Might Lose its Title to a Blimp,", 18 September 2015, Smart News, Smithsonian.com, Smithsonian Institution, Washington, D.C.. Retrieved 22 November 2016."Ask Us—Largest Plane in the World," Aerospaceweb.org. Retrieved 22 November 2016. The aircraft was destroyed during the Russo-Ukrainian War.
The largest military airplanes are the Ukrainian Antonov An-124 Ruslan (world's second-largest airplane, also used as a civilian transport),"World's Second Largest Aircraft," 28 July 2013, NASA. Retrieved 22 November 2016. and American Lockheed C-5 Galaxy transport, weighing, loaded, over .Loftin, Laurence K., Jr., "Wide-Body Transports" , in Chapter 13, "Jet Transports," in Part II, "The Jet Age," in Quest for Performance: The Evolution of Modern Aircraft, NASA SP-468, 1985, Scientific and Technical Information Branch, NASA, Washington, D.C., Updated: 6 August 2004. Retrieved 22 November 2016. The 8-engine, piston/propeller Hughes H-4 Hercules "Spruce Goose"—an American World War II wooden flying boat transport with a greater wingspan (94m/260 ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78 ft)—flew only one short hop in the late 1940s and never flew out of ground effect.