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An aircraft is a

vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses), railed vehicles (trains, trams), watercraft (ships, boats), amphibious vehicles ( ...

that is able to

fly Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced mec ...

fly

by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an

airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of a wing; blade of a propeller rotor or turbine; or sail as seen in cross-section. A solid body moving through a fluid produces an aerodynamic force. The ...

, or in a few cases the downward thrust from

jet engine#REDIRECT Jet engine#REDIRECT Jet engine {{R from other capitalisation ...

{{R from other capitalisation ...

s. Common examples of aircraft include

airplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectrum ...

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally-spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allo ...

airship An airship, dirigible balloon or blimp is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In earl ...

s (including

blimp A blimp, or non-rigid airship, is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships (e.g. Zeppelins), blimps rely on the pressure of the lifting gas (usually helium, rather than hydr ...

s), gliders,

paramotors Powered paragliding, also known as paramotoring or PPG, is a form of ultralight aviation where the pilot wears a back-mounted motor (a paramotor) which provides enough thrust to take off using a paraglider. It can be launched in still air, and ...

and

hot air balloon A hot-air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries pas ...

s. The human activity that surrounds aircraft is called ''

aviation Aviation is the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air balloons an ...

''. The science of aviation, including designing and building aircraft, is called ''

aeronautics Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies ...

.'' Crewed aircraft are flown by an onboard

pilot An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Some other aircrew members, such as navigators or flight engineers, are also considered aviators, because they are ...

, but

unmanned aerial vehicle being tested in California. , a hunter-killer surveillance UAV An unmanned aerial vehicle (UAV) or uncrewed aerial vehicle, also known as unmanned aircraft or uncrewed aircraft (UA), commonly known as a drone, is an aircraft without a human ...

s may be remotely controlled or self-controlled by onboard

computers A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as programs. These programs enable computers to perform a wid ...

. Aircraft may be classified by different criteria, such as lift type,

aircraft propulsion A powered aircraft is an aircraft that uses onboard propulsion with mechanical power generated by an aircraft engine of some kind. Aircraft propulsion nearly always uses either a type of propeller, or a form of jet propulsion. Other potential pr ...

, usage and others.

History

Flying model craft and stories of manned

flight Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be ach ...

flight

go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger hot-air balloons developed in the 18th century. Each of the two

World Wars#REDIRECT world war {{Redirect category shell, 1= {{R from ambiguous term {{R from other capitalisation ...

led to great technical advances. Consequently, the history of aircraft can be divided into five eras: * Pioneers of flight, from the earliest experiments to 1914. *

First World War World War I or the First World War, often abbreviated as WWI or WW1, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously known as the Great War or "the war to end all wars", i ...

, 1914 to 1918. *

Aviation between the World Wars Sometimes dubbed the Golden Age of Aviation, the period in the history of aviation between the end of World War I (1918) and the beginning of World War II (1939) was characterised by a progressive change from the slow wood-and-fabric biplanes of Wo ...

, 1918 to 1939. *

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a global war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all the great powers—forming two opposing milit ...

, 1939 to 1945. * Postwar era, also called the

Jet Age The Jet Age is a period in the history of aviation defined by the advent of aircraft powered by turbine engines, and by the social change this brought about. Jet airliners were able to fly much higher, faster, and farther than older pistonpowere ...

, 1945 to the present day.

Methods of lift

Lighter than air – aerostats

Colorado Springs Hot Air Balloon Competition

Aerostat An aerostat (From Greek ἀήρ ''aer'' (air) + στατός ''statos'' (standing) through French) is a lighter than air aircraft that gains its lift through the use of a buoyant gas. Aerostats include unpowered balloons and powered airships. A ...

s use

buoyancy . Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pr ...

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 relatively low-density gas such as

helium Helium (from el, ἥλιος, Helios, lit=Sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boilin ...

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. With a standard atomic weight of , hydrogen is the lightest element in the periodic table. Hydrogen is the most abundant chemical substance in the universe, constitut ...

, or hot air, which is less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, it adds up to the same weight as the air that the craft displaces. Small hot-air balloons, called

sky lantern A sky lantern (), also known as Kǒngmíng lantern (simplified Chinese: 孔明灯; traditional Chinese: 孔明燈), or Chinese lantern, is a small hot air balloon made of paper, with an opening at the bottom where a small fire is suspended. In ...

s, were first invented in ancient China prior to the 3rd century BC and used primarily in cultural celebrations, and were only the second type of aircraft to fly, the first being

kite . This sparless, ram-air inflated kite, has a complex bridle formed of many strings attached to the face of the wing. A kite is a tethered heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create lift an ...

s, which were first invented in ancient China over two thousand years ago. (See

Han Dynasty The Han dynasty () was the second imperial dynasty of China (202 BC – 220 AD), established by the rebel leader Liu Bang and ruled by the House of Liu. Preceded by the short-lived Qin dynasty (221–206 BC) and a warring interregnum known a ...

)

USS Akron (ZRS-4) in flight over Manhattan, circa 1931-1933

balloon A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...

was originally any aerostat, while the term

was used for large, powered aircraft designs — usually fixed-wing. In 1919

Frederick Handley Page Sir Frederick Handley Page, CBE, FRAeS (15 November 1885 – 21 April 1962) was an English industrialist who was a pioneer in the aircraft industry and became known as the father of the heavy bomber. His company Handley Page Limited was bes ...

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". — though none had yet been built. 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. Huge powered aerostats, characterized by a rigid outer framework and separate aerodynamic skin surrounding the gas bags, were produced, the

Zeppelin A Zeppelin is a type of rigid airship named after the German inventor Count Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp. ...

s being the largest and most famous. 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. Then several accidents, such as the

Hindenburg disaster The ''Hindenburg'' disaster was an airship accident that occurred on May 6, 1937, in Manchester Township, New Jersey, United States. The German passenger airship LZ 129 ''Hindenburg'' caught fire and was destroyed during its attempt to dock with ...

in 1937, led to the demise of these airships. Nowadays a "balloon" is an unpowered aerostat and an "airship" is a powered one. A powered, steerable aerostat is called a ''

dirigible An airship, dirigible balloon or blimp is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In earl ...

''. 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). Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. These soon became known as ''

s''. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a global war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all the great powers—forming two opposing milit ...

, this shape was widely adopted for tethered balloons; in windy weather, this both reduces the strain on the tether and stabilizes the balloon. The nickname ''blimp'' was adopted along with the shape. In modern times, any small dirigible or airship is called a blimp, though a blimp may be unpowered as well as powered.

Heavier-than-air – aerodynes

Heavier-than-air aircraft, such as

s, 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. This dynamic movement through the air is the origin of the term ''aerodyne''. There are two ways to produce dynamic upthrust —

aerodynamic lift A fluid flowing around the surface of an object exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the ...

, and

powered lift A powered lift aircraft takes offs and lands vertically under engine power but uses a fixed wing for horizontal flight. Like helicopters, these aircraft do not need a long runway to take off and land, but they have a speed and performance similar ...

in the form of engine thrust. Aerodynamic lift involving

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed ...

s is the most common, with

fixed-wing aircraft A fixed-wing aircraft is a heavier-than-air flying machine, such as an airplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct f ...

being kept in the air by the forward movement of wings, and

rotorcraft A rotorcraft or rotary-wing aircraft is a heavier-than-air aircraft with rotary wings or rotor blades, which generate lift by rotating around a vertical mast. Several rotor blades mounted on a single mast are referred to as a rotor. The Internatio ...

by spinning wing-shaped rotors sometimes called rotary wings. A wing is a flat, horizontal surface, usually shaped in cross-section as an

aerofoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of a wing; blade of a propeller rotor or turbine; or sail as seen in cross-section. A solid body moving through a fluid produces an aerodynamic force. The ...

. To fly, air must flow over the wing and generate

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Rack lift, a type of elevator ** Ski lift, an aerial or surface lift for uphill transport ** Space elevator, a hypothetical ...

. A ''flexible wing'' is a wing made of fabric or thin sheet material, often stretched over a rigid frame. A ''

'' 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. With powered lift, the aircraft directs its engine thrust vertically downward.

V/STOL A vertical and/or short take-off and landing (V/STOL) aircraft is an airplane able to take-off or land vertically or on short runways. Vertical takeoff and landing (VTOL) aircraft are a subset of V/STOL craft that do not require runways at all. ...

aircraft, such as the

Harrier Jump Jet The Harrier, informally referred to as the Harrier Jump Jet, is a family of jet-powered attack aircraft capable of vertical/short takeoff and landing operations (V/STOL). Named after a bird of prey, it was originally developed by British manuf ...

and Lockheed Martin F-35B take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. A pure

rocket A rocket (from it, rocchetto, , bobbin/spool) is a projectile that spacecraft, aircraft or other vehicle use to obtain thrust from a rocket engine. Rocket engine exhaust is formed entirely from propellant carried within the rocket. Rocket engines ...

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. Rocket-powered missiles that obtain aerodynamic lift at very high speed due to airflow over their bodies are a marginal case.

Fixed-wing

Emirates Airbus A380-861 A6-EER MUC 2015 04

The forerunner of the fixed-wing aircraft is the

. Whereas a fixed-wing aircraft relies on its forward speed to create airflow over the wings, a kite is tethered to the ground and relies on the

wind Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. Winds are commonly classified by their spatial scale, their speed, the types of forces that cause them, the regions in which they ...

blowing over its wings to provide lift. Kites were the first kind of aircraft to fly and were invented in China around 500 BC. Much aerodynamic research was done with kites before test aircraft,

wind tunnel#REDIRECT Wind tunnel#REDIRECT Wind tunnel {{R from other capitalisation ...

{{R from other capitalisation ...
s, and computer modelling programs became available. The first heavier-than-air craft capable of controlled free-flight were gliders. A glider designed by

George Cayley Sir George Cayley, 6th Baronet (27 December 1773 – 15 December 1857) was an English engineer, inventor, and aviator. He is one of the most important people in the history of aeronautics. Many consider him to be the first true scientific aeria ...

carried out the first true manned, controlled flight in 1853. The practical, powered, fixed-wing aircraft (the

or aeroplane) was invented by Wilbur and Orville Wright. Besides the method of

propulsion Propulsion is the action or process of pushing or pulling to drive an object forward. The term is derived from two Latin words: ''pro'', meaning'' before'' or ''forward''; and ''pellere'', meaning ''to drive''. A propulsion system consists of a ...

, fixed-wing aircraft are in general characterized by their

wing configuration The wing configuration of a fixed-wing aircraft (including both gliders and powered aeroplanes) is its arrangement of lifting and related surfaces. Aircraft designs are often classified by their wing configuration. For example, the Supermarine S ...

. The most important wing characteristics are: * Number of wings —

monoplane A monoplane is a fixed-wing aircraft configuration with a single main wing plane, in contrast to a biplane or other multiplane, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing configuratio ...

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a b ...

, etc. * Wing support — Braced or cantilever, rigid, or flexible. * Wing planform — including

aspect ratio The aspect ratio of a geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter sidethe ratio of width to height, when the rectangle is oriented a ...

, angle of sweep, and any variations along the span (including the important class of

delta wing A delta wing is a wing shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta (Δ). Although long studied, it did not find significant applications until the Jet Age, when it proved suitable ...

s). * Location of the horizontal stabilizer, if any. *

Dihedral angle#REDIRECT Dihedral angle#REDIRECT Dihedral angle {{Redirect category shell, 1= {{R from other capitalisation ...

{{Redirect category shell, 1= {{R from other capitalisation ...
— positive, zero, or negative (anhedral). A variable geometry aircraft can change its wing configuration during flight. A ''

flying wing#REDIRECT Flying wing#REDIRECT Flying wing {{R from other capitalisation ...

{{R from other capitalisation ...

'' has no fuselage, though it may have small blisters or pods. The opposite of this is a ''

lifting body A lifting body is a fixed-wing aircraft or spacecraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage wit ...

'', which has no wings, though it may have small stabilizing and control surfaces. Wing-in-ground-effect vehicles are not considered aircraft. They "fly" efficiently close to the surface of the ground or water, like conventional aircraft during takeoff. An example is the Russian ekranoplan (nicknamed the "Caspian Sea Monster"). Man-powered aircraft also rely on

ground effect Ground effect may refer to: * Ground effect (aerodynamics), the increased lift and decreased aerodynamic drag of a wing close to a fixed surface * Ground effect (cars), an effect that creates downforce, primarily in racing cars * Ground effect vehi ...

to remain airborne with minimal pilot power, but this is only because they are so underpowered—in fact, the airframe is capable of flying higher. Flightline at Kabul International Airport

Flightline at Kabul International Airport

Rotorcraft

Rotorcraft, or rotary-wing aircraft, use a spinning rotor with aerofoil section blades (a ''rotary wing'') to provide lift. Types include

autogyro An autogyro (from Greek and , "self-turning"), also known as a gyroplane or gyrocopter, is a type of rotorcraft that uses an unpowered rotor in free autorotation to develop lift. Forward thrust is provided independently, by an engine-driven prop ...

s, and various hybrids such as

gyrodyne A gyrodyne is a type of VTOL aircraft with a helicopter rotor-like system that is driven by its engine for takeoff and landing only, and includes one or more conventional propeller or jet engines to provide forward thrust during cruising flight. ...

s and compound rotorcraft. ''

Helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally-spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allo ...

s'' have a rotor turned by an engine-driven shaft. The rotor pushes air downward to create lift. By tilting the rotor forward, the downward flow is tilted backward, producing thrust for forward flight. Some helicopters have more than one rotor and a few have rotors turned by gas jets at the tips. ''

Autogyro An autogyro (from Greek and , "self-turning"), also known as a gyroplane or gyrocopter, is a type of rotorcraft that uses an unpowered rotor in free autorotation to develop lift. Forward thrust is provided independently, by an engine-driven prop ...

s'' have unpowered rotors, with a separate power plant to provide thrust. The rotor is tilted backward. As the autogyro moves forward, air blows upward across the rotor, making it spin. This spinning increases the speed of airflow over the rotor, to provide lift.

Rotor kite A rotor kite or gyrokite is an unpowered, rotary-wing aircraft. Like an autogyro or helicopter, it relies on lift created by one or more sets of rotors in order to fly. Unlike a helicopter, gyrokites and rotor kites do not have an engine powering ...

s are unpowered autogyros, which are towed to give them forward speed or tethered to a static anchor in high-wind for kited flight. ''

Cyclogyro Concept drawing of a cyclogyro. The cyclogyro, or cyclocopter, is an aircraft configuration that uses a horizontal-axis cyclorotor as a rotor wing to provide lift and sometimes also propulsion and control. In principle, the cyclogyro is capable of v ...

s'' rotate their wings about a horizontal axis. ''Compound rotorcraft'' have wings that provide some or all of the lift in forward flight. They are nowadays classified as ''

'' types and not as rotorcraft. ''

Tiltrotor A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a transverse ...

'' aircraft (such as the

Bell Boeing V-22 Osprey The Bell Boeing V-22 Osprey is an American multi-mission, tiltrotor military aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed to combine the functionality of a conventional ...

tiltwing A tiltwing aircraft features a wing that is horizontal for conventional forward flight and rotates up for vertical takeoff and landing. It is similar to the tiltrotor design where only the propeller and engine rotate. Tiltwing aircraft are typicall ...

tail-sitter The Convair Pogo was one tailsitter design. A tail-sitter, or tailsitter, is a type of VTOL aircraft that takes off and lands on its tail, then tilts horizontally for forward flight. Originating in the 1920s with the inventor Nikola Tesla, the firs ...

, and coleopter aircraft have their rotors/

propellers . A propeller is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral, that, when rotated, performs an action which is similar to Archimedes' screw. It transforms rotational power into linear thrust by ...

horizontal for vertical flight and vertical for forward flight.

Other methods of lift

* A ''

'' is an aircraft body shaped to produce lift. If there are any wings, they are too small to provide significant lift and are used only for stability and control. Lifting bodies are not efficient: they suffer from high drag, and must also travel at high speed to generate enough lift to fly. Many of the research prototypes, such as the

Martin Marietta X-24 The Martin Marietta X-24 was an American experimental aircraft developed from a joint United States Air Force-NASA program named PILOT (1963–1975). It was designed and built to test lifting body concepts, experimenting with the concept of unpow ...

, which led up to the

Space Shuttle The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program name was Space ...

, were lifting bodies, though the Space Shuttle is not, and some

supersonic F/A-18F Super Hornet in transonic flight Image:FA-18 Hornet breaking sound barrier (7 July 1999) - filtered.jpg, 275px, U.S. Navy F/A-18 Hornet, F/A-18 approaching the sound barrier. The white cloud forms as a result of the Prandtl–Meyer expan ...

missile In military terminology, a missile, also known as a guided missile or guided rocket, is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles have four system components: targeting/g ...

s obtain lift from the airflow over a tubular body. * ''

Powered lift A powered lift aircraft takes offs and lands vertically under engine power but uses a fixed wing for horizontal flight. Like helicopters, these aircraft do not need a long runway to take off and land, but they have a speed and performance similar ...

'' types rely on engine-derived lift for vertical takeoff and landing (

VTOL A vertical take-off and landing (VTOL) aircraft is one that can hover, take off, and land vertically. This classification can include a variety of types of aircraft including fixed-wing aircraft as well as helicopters and other aircraft with pow ...

). Most types transition to fixed-wing lift for horizontal flight. Classes of powered lift types include

jet aircraft (such as the

) and

tiltrotor A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a transverse ...

s, such as the

, among others. A few experimental designs rely entirely on engine thrust to provide lift throughout the whole flight, including personal fan-lift hover platforms and jetpacks.

research designs include the

Rolls-Royce Thrust Measuring Rig The Rolls-Royce Thrust Measuring Rig (TMR), was a pioneering vertical take-off and landing (VTOL) aircraft developed by Rolls-Royce in the 1950s. It has the distinction of being "the first jet-lift aircraft to fly anywhere in the world". The d ...

. * The ''

Flettner airplane A Flettner airplane is a type of rotor airplane which uses a Flettner rotor to provide lift. The rotor comprises a spinning cylinder with circular end plates and, in an aircraft, spins about a spanwise horizontal axis. When the aircraft moves for ...

'' uses a rotating cylinder in place of a fixed wing, obtaining lift from the

Magnus effect Magnus effect in a 2D liquid of hard disks The Magnus effect is an observable phenomenon that is commonly associated with a spinning object moving through air or another fluid. The path of the spinning object is deflected in a manner that is not ...

. * The ''

ornithopter An ornithopter (from Greek ''ornithos'' "bird" and ''pteron'' "wing") is an aircraft that flies by flapping its wings. Designers seek to imitate the flapping-wing flight of birds, bats, and insects. Though machines may differ in form, they are usu ...

'' obtains thrust by flapping its wings.

Scale, sizes and speeds

Sizes

The smallest aircraft are toys/recreational items, and even smaller, nano-aircraft. 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, Ivan
"The world's largest aircraft crashes after 2nd test flight"
, 24 August 2016, ''CNN Tech'' on

CNN Cable News Network (CNN) is a multinational news-based pay television channel headquartered in Atlanta. It is owned by CNN Worldwide, a unit of the WarnerMedia News & Sports division of AT&T's WarnerMedia. It was founded in 1980 by American m ...

CNN

, the Cable News Network, retrieved 22 November 2016. The largest aircraft by weight and largest regular fixed-wing aircraft ever built, , is the Antonov An-225 ''Mriya''. That Ukrainian-built six-engine Russian transport of the 1980s is long, with an wingspan. It holds the world payload record, after transporting of goods, and has recently flown loads commercially. With a maximum loaded weight of , it is also the heaviest aircraft built to date. It can cruise at ."Watch the world's biggest plane land in Australia,"
16 May 2016, Fox News, retrieved 22 November 2016.Rumbaugh, Andrea
"World's biggest airplane lands at Bush airport,"
Updated 18 November 2016, ''Houston Chonicle'' / Chron.com, 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 The Smithsonian Institution ( ), also known simply as The Smithsonian, is a trust instrumentality of the United States composed as a group of museums and research centers. It was founded on August 10, 1846, "for the increase and diffusion of kno ...

, Washington, D.C., retrieved 22 November 2016."Ask Us – Largest Plane in the World,"
Aerospaceweb.org, retrieved 22 November 2016. The largest military airplanes are the Ukrainian/Russian Antonov An-124 ''Ruslan'' (world's second-largest airplane, also used as a civilian transport),"World's Second Largest Aircraft,"
28 July 2013,

NASA The National Aeronautics and Space Administration (NASA; ) is an independent agency of the U.S. federal government responsible for the civilian space program, as well as aeronautics and space research. NASA was established in 1958, succeedi ...

, retrieved 22 November 2016. and American

Lockheed C-5 Galaxy The Lockheed C-5 Galaxy is a large military transport aircraft originally designed and built by Lockheed, and now maintained and upgraded by its successor, Lockheed Martin. It provides the United States Air Force (USAF) with a heavy intercontine ...

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,

, Washington, D.C., Updated: 6 August 2004, retrieved 22 November 2016. The 8-engine, piston/propeller Hughes H-4 ''Hercules'' "Spruce Goose" — an American

wooden flying boat transport with a greater wingspan (94m/260ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78ft) — flew only one short hop in the late 1940s and never flew out of

. The largest civilian airplanes, apart from the above-noted An-225 and An-124, are the

Airbus Beluga The Airbus A300-600ST (Super Transporter), or Beluga, is a version of the standard A300-600 wide-body airliner modified to carry aircraft parts and outsize cargo. It received the official name of ''Super Transporter'' early on; however, the name ' ...

cargo transport derivative of the

Airbus A300 The Airbus A300 is a wide-body airliner developed and manufactured by Airbus. In September 1967, aircraft manufacturers in the United Kingdom, France, and West Germany signed a memorandum of understanding to develop a large airliner. West Germ ...

jet airliner, the

Boeing Dreamlifter The Boeing 747 Dreamlifter, also known as the Boeing 747-400 Large Cargo Freighter (LCF), is a wide-body cargo aircraft modified extensively from the Boeing 747-400 airliner. With a volume of 65,000 cubic feet (1,840 m³) the Dreamlifter can ho ...

cargo transport derivative of the

Boeing 747 The Boeing 747 is a large, long–range wide-body airliner and cargo aircraft manufactured by Boeing Commercial Airplanes in the United States. After introducing the 707 in October 1958, Pan Am wanted a jet times its size, to reduce its seat ...

jet airliner/transport (the 747-200B was, at its creation in the 1960s, the heaviest aircraft ever built, with a maximum weight of over ), and the double-decker

Airbus A380 The Airbus A380 is a wide-body aircraft manufactured by Airbus. It is the world's largest passenger airliner. Airbus studies started in 1988 and the project was announced in 1990 to challenge the dominance of the Boeing 747 in the long hau ...

"super-jumbo" jet airliner (the world's largest passenger airliner)."Airbus reviews A380 schedule,"
29 April 2008, ''

The New York Times ''The New York Times'' (''NYT'' or ''NY Times'') is an American daily newspaper based in New York City with a worldwide readership. Founded in 1851, the ''Times'' has since won 130 Pulitzer Prizes (the most of any newspaper), and has long be ...

'', retrieved 22 November 2016.

Speeds

The fastest recorded powered aircraft flight and fastest recorded aircraft flight of an air-breathing powered aircraft was of the

NASA X-43 The NASA X-43 was an experimental unmanned hypersonic aircraft with multiple planned scale variations meant to test various aspects of hypersonic flight. It was part of the X-plane series and specifically of NASA's Hyper-X program. It set several ...

A ''Pegasus'', a

scramjet A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully befo ...

-powered,

hypersonic Simulation of hypersonic speed (Mach 5) In aerodynamics, a hypersonic speed is one that greatly exceeds the speed of sound, often stated as starting at speeds of Mach 5 and above. The precise Mach number at which a craft can be said to be flyin ...

experimental research aircraft, at Mach 9.6, exactly . The X-43A set that new mark, and broke its own world record of Mach 6.3, exactly , set in March 2004, on its third and final flight on 16 November 2004."Hypersonic X-43A Takes Flight.htm,"

retrieved November 2016."Fastest aircraft, air-breathing engine,"
Guinness World Records, retrieved 2 December 2016. Prior to the X-43A, the fastest recorded powered airplane flight (and still the record for the fastest manned, powered airplane / fastest manned, non-spacecraft aircraft) was of the

North American X-15A-2

, rocket-powered airplane at Mach 6.72, or , on 3 October 1967. On one flight it reached an altitude of .Jackson, Doug
"Ask Us – Aircraft Speed Records,"
22 April 2001, Aerospaceweb.org, retrieved 22 November 2016."Fastest speed in a non-spacecraft aircraft,"
Guinness World Records, retrieved 2 December 2016.Bergqvist, Pia
"Fastest Airplanes: Top Performers in Their Class,"
17 September 2014, '' Flying'', retrieved 3 December 2016 The fastest known, production aircraft (other than rockets and missiles) currently or formerly operational (as of 2016) are: * The fastest fixed-wing aircraft, and fastest glider, is the

, a rocket-glider hybrid, which has re-entered the atmosphere as a fixed-wing glider at more than Mach 25, equal to .Benson, Tom, ed.
"Speed Regimes: Hypersonic Re-Entry,"
Glenn Research Center,

, retrieved 22 November 2016. * The fastest military airplane ever built:

Lockheed SR-71 Blackbird The Lockheed SR-71 "Blackbird" is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed and manufactured by the American aerospace company Lockheed Corporation. It was operated by both the United States Air Forc ...

, a U.S.

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmishers, ...

jet fixed-wing aircraft, known to fly beyond Mach 3.3, equal to . On 28 July 1976, an SR-71 set the record for the fastest and highest-flying operational aircraft with an absolute speed record of and an absolute altitude record of . At its retirement in the January 1990, it was the fastest air-breathing aircraft / fastest jet aircraft in the world, a record still standing ."Lockheed SR-71A,"
display notes, 29 May 2015,

National Museum of the United States Air Force National may refer to: Common uses * Nation or country ** Nationality – a ''national'' is a person who is subject to a nation, regardless of whether the person has full rights as a citizen ** National (distribution), a type of product or publi ...

retrieved 2 December 2016Trujillo, Staff Sgt. Robert M
"SR-71 Blackbird: Gone but not forgotten,"
26 January 2016, 9th Reconnaissance Wing Public Affairs, U.S. Air Force, retrieved 2 December 2016"Absolute speed record still stands 40 years later," 27 July 2016 ''General Aviation News'', retrieved 22 November 2016.Woolen, Angela
"SR-71 pilots, crew relive absolute speed record,"
9 August 2016, 78th Air Base Wing Public Affairs, United States Air Force, retrieved 2 December 2016 :Note: Some sources refer to the above-mentioned X-15 as the "fastest military airplane" because it was partly a project of the U.S. Navy and Air Force; however, the X-15 was not used in non-experimental actual military operations. * The fastest current military aircraft are the Soviet/Russian

Mikoyan-Gurevich MiG-25 The Mikoyan-Gurevich MiG-25 (russian: Микоян и Гуревич МиГ-25; NATO reporting name: Foxbat) is a supersonic interceptor and reconnaissance aircraft that was among the fastest military aircraft to enter service. It was designed ...

— capable of Mach 3.2, equal to , at the expense of engine damage, or Mach 2.83, equal to , normally — and the Russian

Mikoyan MiG-31 The Mikoyan MiG-31 (russian: Микоян МиГ-31; NATO reporting name: Foxhound) is a supersonic interceptor aircraft that was developed for use by the Soviet Air Forces. The aircraft was designed by the Mikoyan design bureau as a replacemen ...

E (also capable of Mach 2.83 normally). Both are fighter-interceptor jet airplanes, in active operations as of 2016. Bender, Jeremy and Amanda Macias
"The 9 fastest piloted planes in the world,"
18 September 2015, ''Business Insider'', retrieved 3 December 2016"Fast and furious — the world's fastest military aircraft,"
''Airforce Technology'', retrieved 3 December 2016The Five Fastest Military Jets Ever Made","
2016, Bloomberg, retrieved 3 December 2016 * The fastest civilian airplane ever built, and fastest passenger airliner ever built: the briefly operated

Tupolev Tu-144 The Tupolev Tu-144 (russian: Tyполев Ту-144; NATO reporting name: Charger) is a Soviet supersonic passenger airliner designed by Tupolev in operation from 1968 to 1999. The Tu-144 was the world's first commercial supersonic transport airc ...

supersonic jet airliner (Mach 2.35, 1,600 mph, 2,587 km/h), which was believed to cruise at about Mach 2.2. The Tu-144 (officially operated from 1968 to 1978, ending after two crashes of the small fleet) was outlived by its rival, the ''

Concorde The Aérospatiale/BAC Concorde () is a British–French turbojet-powered supersonic passenger airliner that was operated from 1976 until 2003. It had a maximum speed over twice the speed of sound, at Mach 2.04 ( at cruise altitude), with seat ...

'' (Mach 2.23), a French/British supersonic airliner, known to cruise at Mach 2.02 (1.450 mph, 2,333 kmh at cruising altitude), operating from 1976 until the small Concorde fleet was grounded permanently in 2003, following the crash of one in the early 2000s."Fastest aircraft, airliner,"
Guinness World Records, retrieved 2 December. 2016. * The fastest civilian airplane currently flying: the

Cessna Citation X The Cessna Citation X is an American business jet produced by Cessna and part of the Citation family. Announced at the October 1990 NBAA convention, the Model 750 made its maiden flight on December 21, 1993, received its type certification on Ju ...

, an American business jet, capable of Mach 0.935, or . Its rival, the American

Gulfstream G650 The Gulfstream G650 is a large business jet produced by Gulfstream Aerospace.

business jet, can reach Mach 0.925, or "Cessna rolls out first production unit of new Citation X,"
15 April 2013, ''Wichita Business Journal'', retrieved 22 November 2016. * The fastest airliner currently flying is the

, quoted as being capable of cruising over Mach 0.885, . Previously, the fastest were the troubled, short-lived Russian (Soviet Union)

SST (Mach 2.35; equal to ) and the French/British ''Concorde'', with a maximum speed of Mach 2.23 or and a normal cruising speed of Mach 2 or ."Ask Us – Fastest Airliner and Area Rule,"
Aerospaceweb.org, retrieved 22 November 2016. Before them, the

Convair 990 Coronado The Convair 990 Coronado is an American narrow-body four-engined jet airliner produced by the Convair division of General Dynamics, a stretched version of their earlier Convair 880 produced in response to a request from American Airlines. The 99 ...

jet airliner of the 1960s flew at over .

Propulsion

Unpowered aircraft

Gliders are heavier-than-air aircraft that do not employ propulsion once airborne. Take-off may be by launching forward and downward from a high location, or by pulling into the air on a tow-line, either by a ground-based winch or vehicle, or by a powered "tug" aircraft. For a glider to maintain its forward air speed and lift, it must descend in relation to the air (but not necessarily in relation to the ground). Many gliders can "soar", ''i.e.'', gain height from updrafts such as thermal currents. The first practical, controllable example was designed and built by the British scientist and pioneer

, whom many recognise as the first aeronautical engineer. Common examples of gliders are

sailplanes A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplanes ...

hang gliders Hang gliding is an air sport or recreational activity in which a pilot flies a light, non-motorised foot-launched heavier-than-air aircraft called a hang glider. Most modern hang gliders are made of an aluminium alloy or composite frame covered w ...

and paragliders.

Balloons A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...

drift with the wind, though normally the pilot can control the altitude, either by heating the air or by releasing ballast, giving some directional control (since the wind direction changes with altitude). A wing-shaped hybrid balloon can glide directionally when rising or falling; but a spherically shaped balloon does not have such directional control.

Kite . This sparless, ram-air inflated kite, has a complex bridle formed of many strings attached to the face of the wing. A kite is a tethered heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create lift an ...

s are aircraft that are tethered to the ground or other object (fixed or mobile) that maintains tension in the tether or

kite line In kiting, a line is the string made of cotton, nylon, silk or wire, which connects the kite to the person operating it or an anchor. Kites have a set of wings, a set of anchors, and a set of lines coupling the wings with the anchors. Kite lines per ...

; they rely on virtual or real wind blowing over and under them to generate lift and drag.

Kytoon A kytoon or kite balloon is a tethered aircraft which obtains some of its lift dynamically as a heavier-than-air kite and the rest aerostatically as a lighter-than-air balloon. The word is a portmanteau of kite and balloon. The primary advantage o ...

s are balloon-kite hybrids that are shaped and tethered to obtain kiting deflections, and can be lighter-than-air, neutrally buoyant, or heavier-than-air.

Powered aircraft

Powered aircraft have one or more onboard sources of mechanical power, typically

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many s ...

s although rubber and manpower have also been used. Most aircraft engines are either lightweight

reciprocating engine , internal combustion piston engine. A reciprocating engine, also often known as a piston engine, is typically a heat engine (although there are also pneumatic and hydraulic reciprocating engines) that uses one or more reciprocating pistons to con ...

s or

gas turbine A gas turbine, also called a combustion turbine, is a type of continuous and internal combustion engine. The main elements common to all gas turbine engines are: * an upstream rotating gas compressor * a combustor * a downstream turbine on the sam ...

s. Engine fuel is stored in tanks, usually in the wings but larger aircraft also have additional

fuel tank A fuel tank (also called a petrol tank or gas tank) is a safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled ( ...

s in the

fuselage In aeronautics, the fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, and cargo. In single-engine aircraft, it will usually contain an engine, as well, although in some amphib ...

Propeller aircraft

Propeller aircraft A powered aircraft is an aircraft that uses onboard propulsion with mechanical power generated by an aircraft engine of some kind. Aircraft propulsion nearly always uses either a type of propeller, or a form of jet propulsion. Other potential pr ...

use one or more

(airscrews) to create thrust in a forward direction. The propeller is usually mounted in front of the power source in ''

tractor configuration An aircraft constructed with a tractor configuration has the engine mounted with the airscrew in front of it so that the aircraft is "pulled" through the air, as opposed to the pusher configuration, in which the airscrew is behind and propels th ...

'' but can be mounted behind in ''

pusher configuration In an aircraft with a pusher configuration (as opposed to a tractor configuration), the propeller(s) are mounted behind their respective engine(s). According to British aviation author Bill Gunston, a "pusher propeller" is one mounted behind the en ...

''. Variations of propeller layout include ''

contra-rotating propellers Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston or turboprop engine to drive two coaxial propellers in c ...

'' and ''

ducted fan#REDIRECT Ducted fan#REDIRECT Ducted fan {{R from other capitalisation ...

{{R from other capitalisation ...
s''. Many kinds of power plant have been used to drive propellers. Early airships used man power or

steam engines from Stott Park Bobbin Mill, Cumbria, England A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside ...

. The more practical

internal combustion piston engine An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, t ...

was used for virtually all fixed-wing aircraft until

and is still used in many smaller aircraft. Some types use turbine engines to drive a propeller in the form of a

turboprop A turboprop engine is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air is drawn into the intake and compressed by the compress ...

propfan A propfan, also called an open rotor engine, or unducted fan (as opposed to a ducted fan), is a type of aircraft engine related in concept to both the turboprop and turbofan, but distinct from both. The design is intended to offer the speed and ...

Human-powered flight HPAs are aircraft belonging to the class of vehicles known as human-powered vehicles. Early attempts at human-powered flight were unsuccessful because of the difficulty of achieving the high power-to-weight ratio. Prototypes often used ornithopter ...

has been achieved, but has not become a practical means of transport. Unmanned aircraft and models have also used power sources such as

electric motors#REDIRECT Electric motor#REDIRECT Electric motor#REDIRECT Electric motor {{R from other capitalisation ... {{R from other capitalisation ...

{{R from other capitalisation ...
and rubber bands.

Jet aircraft

Jet aircraft A jet aircraft (or simply jet) is an aircraft (nearly always a fixed-wing aircraft) propelled by jet engines. Whereas the engines in propeller-powered aircraft generally achieve their maximum efficiency at much lower speeds and altitudes, jet e ...

use

airbreathing jet engine An airbreathing jet engine (or ''ducted jet engine'') is a jet engine that emits a jet of hot exhaust gases formed from air that is forced into the engine by several stages of centrifugal, axial or ram compression, which is then heated and expanded ...

s, which take in air, burn fuel with it in a

combustion chamber Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

, and accelerate the exhaust rearwards to provide thrust. Different jet engine configurations include the

turbojet The turbojet is an airbreathing jet engine, typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet, a compressor, a combustion chamber, and a turbine (that drives the compressor). T ...

and

turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which achieves mechanical ...

, sometimes with the addition of an

afterburner An afterburner (or reheat U.K.) is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat. Afterburning in ...

. Those with no rotating turbomachinery include the

pulsejet A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need to have air forced into its inle ...

and

ramjet A ramjet, sometimes referred to as a flying stovepipe or an athodyd (aero thermodynamic duct), is a form of airbreathing jet engine that uses the engine's forward motion to compress incoming air without an axial compressor or a centrifugal compr ...

. These mechanically simple engines produce no thrust when stationary, so the aircraft must be launched to flying speed using a catapult, like the

V-1 flying bomb The V-1 flying bomb (german: Vergeltungswaffe 1 "Vengeance Weapon 1")—also known to the Allies as the buzz bomb, or doodlebug, and in Germany as (cherry stone) or (maybug), as well as by its official aircraft designation of Fi 103—was an ...

, or a rocket, for example. Other engine types include the

motorjet A motorjet is a rudimentary type of jet engine which is sometimes referred to as ''thermojet'', a term now commonly used to describe a particular and completely unrelated pulsejet design. Design At the heart the motorjet is an ordinary piston ...

and the dual-cycle

Pratt & Whitney J58 The Pratt & Whitney J58 (company designation JT11D-20) was an American jet engine that powered the Lockheed A-12, and subsequently the YF-12 and the SR-71 aircraft. It was an afterburning turbojet with a unique compressor bleed to the afterburner ...

. Compared to engines using propellers, jet engines can provide much higher thrust, higher speeds and, above about , greater efficiency. They are also much more fuel-efficient than

s. As a consequence nearly all large, high-speed or high-altitude aircraft use jet engines.

Rotorcraft

Some rotorcraft, such as

s, have a powered rotary wing or ''rotor'', where the rotor disc can be angled slightly forward so that a proportion of its lift is directed forwards. The rotor may, like a propeller, be powered by a variety of methods such as a piston engine or turbine. Experiments have also used jet nozzles at the rotor blade tips.

Other types of powered aircraft

* ''

Rocket-powered aircraft A rocket-powered aircraft or rocket plane is an aircraft that uses a rocket engine for propulsion, sometimes in addition to airbreathing jet engines. Rocket planes can achieve much higher speeds than similarly sized jet aircraft, but typically ...

'' have occasionally been experimented with, and the Messerschmitt Me 163 ''Komet'' fighter even saw action in the Second World War. Since then, they have been restricted to research aircraft, such as the

North American X-15 The North American X-15 is a hypersonic rocket-powered aircraft. It was operated by the United States Air Force and the National Aeronautics and Space Administration as part of the X-plane series of experimental aircraft. The X-15 set speed and ...

, which traveled up into space where air-breathing engines cannot work (rockets carry their own oxidant). Rockets have more often been used as a supplement to the main power plant, typically for the rocket-assisted take off of heavily loaded aircraft, but also to provide high-speed dash capability in some hybrid designs such as the

Saunders-Roe SR.53 The Saunders-Roe SR.53 was a British prototype interceptor aircraft of mixed jet and rocket propulsion developed for the Royal Air Force (RAF) by Saunders-Roe in the early 1950s. As envisaged, the SR.53 would have been used as an interceptor air ...

. * The ''

'' obtains thrust by flapping its wings. It has found practical use in a model hawk used to freeze prey animals into stillness so that they can be captured, and in toy birds.

Design and construction

Aircraft are

designed A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process, or the result of that plan or specification in the form of a prototype, product or process. The verb ''to design'' ...

according to many factors such as customer and manufacturer demand,

safety Safety is the state of being "safe", the condition of being protected from harm or other non-desirable outcomes. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk. Meanings There are tw ...

protocols and physical and economic constraints. For many types of aircraft the design process is regulated by national airworthiness authorities. The key parts of an aircraft are generally divided into three categories: * The ''structure'' comprises the main load-bearing elements and associated equipment. * The ''propulsion system'' (if it is powered) comprises the power source and associated equipment, as described above. * The ''avionics'' comprise the control, navigation and communication systems, usually electrical in nature.

Structure

The approach to structural design varies widely between different types of aircraft. Some, such as paragliders, comprise only flexible materials that act in tension and rely on aerodynamic pressure to hold their shape. A

similarly relies on internal gas pressure, but may have a rigid basket or gondola slung below it to carry its payload. Early aircraft, including

s, often employed flexible doped

aircraft fabric covering Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures, the de Havilland Mosquito being an example of this technique, and on ...

to give a reasonably smooth aeroshell stretched over a rigid frame. Later aircraft employed semi-

monocoque Monocoque (), also called structural skin, is a structural system in which loads are supported by an object's external skin, similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, a true monocoq ...

techniques, where the skin of the aircraft is stiff enough to share much of the flight loads. In a true monocoque design there is no internal structure left. With the recent emphasis on sustainability hemp has picked up some attention, having a way smaller carbon foot print and 10 times stronger than steel, hemp could become the standard of manufacturing in the future. The key structural parts of an aircraft depend on what type it is.

Aerostats

Lighter-than-air types are characterised by one or more gasbags, typically with a supporting structure of flexible cables or a rigid framework called its hull. Other elements such as engines or a gondola may also be attached to the supporting structure.

Aerodynes

Heavier-than-air types are characterised by one or more wings and a central

. The fuselage typically also carries a tail or

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third edi ...

for stability and control, and an undercarriage for takeoff and landing. Engines may be located on the fuselage or wings. On a

the wings are rigidly attached to the fuselage, while on a

the wings are attached to a rotating vertical shaft. Smaller designs sometimes use flexible materials for part or all of the structure, held in place either by a rigid frame or by air pressure. The fixed parts of the structure comprise the

airframe The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and exclude the propulsion system. Airframe design is a field of aerospace engi ...

Avionics

The avionics comprise the

aircraft flight control system A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. Aircraft en ...

s and related equipment, including the

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls that enab ...

instrumentation, navigation,

radar Radar is a detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system cons ...

, monitoring, and

communications system 400px, Communication system A communications system or communication system is a collection of individual telecommunications networks, transmission systems, relay stations, tributary stations, and terminal equipment usually capable of interconn ...

Flight characteristics

Flight envelope

The flight envelope of an aircraft refers to its approved design capabilities in terms of

airspeed Aircraft have pitot tubes for measuring airspeed. Airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are indicated airspeed ("IAS"), calibrated airspeed ("CAS"), equivalent airspeed ("EAS ...

, load factor and altitude. The term can also refer to other assessments of aircraft performance such as maneuverability. When an aircraft is abused, for instance by diving it at too-high a speed, it is said to be flown ''outside the envelope'', something considered foolhardy since it has been taken beyond the design limits which have been established by the manufacturer. Going beyond the envelope may have a known outcome such as

flutter

or entry to a non-recoverable spin (possible reasons for the boundary).

Range

The range is the distance an aircraft can fly between

takeoff Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a tr ...

and

landing of Ryanair makes a smoky landing at Bristol Airport (2016) lands on a moving trailer as part of an airshow. File:F-18 - A 3-wire landing.ogv">F-18 landing on an aircraft carrier Landing is the last part of a flight, where a flying ...

, as limited by the time it can remain airborne. For a powered aircraft the time limit is determined by the fuel load and rate of consumption. For an unpowered aircraft, the maximum flight time is limited by factors such as weather conditions and pilot endurance. Many aircraft types are restricted to daylight hours, while balloons are limited by their supply of lifting gas. The range can be seen as the average ground speed multiplied by the maximum time in the air. The

Airbus A350 The Airbus A350 is a long-range, wide-body jet airliner developed by Airbus. The first A350 design proposed by Airbus in 2004, in response to the Boeing 787 Dreamliner, would have been a development of the A330 with composite wings and new ...

is now the longest range airliner.

Flight dynamics

Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the

angles of rotation 250px, The angle of rotation from the black ray to the green segment is 60°, from the black ray to the blue segment is 210°, and from the green to the blue segment is . A complete °,_or_2pi.html" style="text-decoration: none;"class="mw-redirec ...

around three axes which pass through the vehicle's

center of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may b ...

, known as ''

pitch Pitch may refer to: Acoustic frequency * Pitch (music), the perceived frequency of sound including "definite pitch" and "indefinite pitch" ** Absolute pitch or "perfect pitch" ** Pitch class, a set of all pitches that are a whole number of octaves ...

'', ''

roll Roll or Rolls may refer to: Arts, entertainment and media * ''Roll'' (Anne McCue album), 2004 * ''Roll'' (Emerson Drive album), 2012 * "Roll", a song by Flo Rida from the 2008 album ''Mail on Sunday (album)'' * Roll (''Mega Man''), a character in ...

,'' and '' yaw''. * Roll is a rotation about the longitudinal axis (equivalent to the rolling or heeling of a ship) giving an up-down movement of the wing tips measured by the roll or bank angle. * Pitch is a rotation about the sideways horizontal axis giving an up-down movement of the aircraft nose measured by the

angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. ...

. * Yaw is a rotation about the vertical axis giving a side-to-side movement of the nose known as sideslip. Flight dynamics is concerned with the stability and control of an aircraft's rotation about each of these axes.

Stability

An aircraft that is unstable tends to diverge from its intended flight path and so is difficult to fly. A very stable aircraft tends to stay on its flight path and is difficult to maneuver. Therefore, it is important for any design to achieve the desired degree of stability. Since the widespread use of digital computers, it is increasingly common for designs to be inherently unstable and rely on computerised control systems to provide artificial stability. A fixed wing is typically unstable in pitch, roll, and yaw. Pitch and yaw stabilities of conventional fixed wing designs require horizontal and vertical stabilisers,Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', p. 194. Aviation Supplies & Academics, 1997. Aviation Publishers Co. Limited, ''From the Ground Up'', p. 10 (27th revised edition) which act similarly to the feathers on an arrow. These stabilizing surfaces allow equilibrium of aerodynamic forces and to stabilise the

flight dynamics Flight dynamics is the study of the performance, stability, and control of vehicles flying through the air or in outer space. It is concerned with how forces acting on the vehicle determine its velocity and attitude with respect to time. For a fi ...

of pitch and yaw. They are usually mounted on the tail section (

), although in the

canard Canard is French for duck, a type of aquatic bird. In both English and French, ''canard'' may mean an unfounded rumor or story. Canard may also refer to: Aviation *Canard (aeronautics), a small wing in front of an aircraft's main wing *Aviafib ...

layout, the main aft wing replaces the canard foreplane as pitch stabilizer.

Tandem wing QAC Quickie Q2 A tandem wing aircraft has two main wings, with one located forward and the other to the rear. Both wings contribute to lift. Tandem wing aircraft may be distinguished from: * A biplane whose wings are stacked more or less vertic ...

and

tailless aircraft A tailless aircraft has no tail assembly and no other horizontal surface besides its main wing. The aerodynamic control and stabilisation functions in both pitch and roll are incorporated into the main wing. A tailless type may still have a conven ...

rely on the same general rule to achieve stability, the aft surface being the stabilising one. A rotary wing is typically unstable in yaw, requiring a vertical stabiliser. A balloon is typically very stable in pitch and roll due to the way the payload is slung underneath the center of lift.

Control

Flight control surfaces Aircraft flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude. Development of an effective set of flight control surfaces was a critical advance in the development of aircraft. Earl ...

enable the pilot to control an aircraft's flight attitude and are usually part of the wing or mounted on, or integral with, the associated stabilizing surface. Their development was a critical advance in the history of aircraft, which had until that point been uncontrollable in flight.

Aerospace engineers Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is simil ...

develop

control system A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial contro ...

s for a vehicle's orientation (attitude) about its

center of mass In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may b ...

. The control systems include actuators, which exert forces in various directions, and generate rotational forces or moments about the

aerodynamic center The torques or moments acting on an airfoil moving through a fluid can be accounted for by the net lift and net drag applied at some point on the airfoil, and a separate net pitching moment about that point whose magnitude varies with the choice ...

of the aircraft, and thus rotate the aircraft in pitch, roll, or yaw. For example, a

pitching moment In aerodynamics, the pitching moment on an airfoil is the moment (or torque) produced by the aerodynamic force on the airfoil if that aerodynamic force is considered to be applied, not at the center of pressure, but at the aerodynamic center of the ...

is a vertical force applied at a distance forward or aft from the aerodynamic center of the aircraft, causing the aircraft to pitch up or down. Control systems are also sometimes used to increase or decrease drag, for example to slow the aircraft to a safe speed for landing. The two main aerodynamic forces acting on any aircraft are lift supporting it in the air and drag opposing its motion. Control surfaces or other techniques may also be used to affect these forces directly, without inducing any rotation.

Impacts of aircraft use

Aircraft permit long distance, high speed

travel Travel is the movement of people between distant geographical locations. Travel can be done by foot, bicycle, automobile, train, boat, bus, airplane, ship or other means, with or without luggage, and can be one way or round trip. Travel can ...

and may be a more

fuel efficient A fuel is any material that can be made to react with other substances so that it releases energy as heat energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has ...

mode of transportation in some circumstances. Aircraft have environmental and climate impacts beyond fuel efficiency considerations, however. They are also relatively noisy compared to other forms of travel and high altitude aircraft generate

contrail Contrails (; short for "condensation trails") or vapor trails are line-shaped clouds produced by aircraft engine exhaust or changes in air pressure, typically at aircraft cruising altitudes several miles above the Earth's surface. Contrails are ...

s, which experimental evidence suggests may alter weather patterns.

Uses for aircraft

Aircraft are produced in several different types optimized for various uses;

military aircraft A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat: * Combat aircraft are designed to destroy enemy equipme ...

, which includes not just combat types but many types of supporting aircraft, and

civil aircraft Civil aviation is one of two major categories of flying, representing all non-military aviation, both private and commercial. Most of the countries in the world are members of the International Civil Aviation Organization (ICAO) and work together ...

, which include all non-military types, experimental and model.

Military

A military aircraft is any aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat: * Combat aircraft are aircraft designed to destroy enemy equipment using its own armament. Combat aircraft divide broadly into fighters and

bomber A bomber is a combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped from an aircraft occurred ...

s, with several in-between types, such as

fighter-bomber A fighter-bomber is a fighter aircraft that has been modified, or used primarily, as a light bomber or attack aircraft. It differs from bomber and attack aircraft primarily in its origins, as a fighter that has been adapted into other roles, whe ...

s and

attack aircraft An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers, and is prepared to encounter strong low-level air defenses while pressing ...

, including

attack helicopter#REDIRECT Attack helicopter#REDIRECT Attack helicopter {{R from other capitalisation ...

{{R from other capitalisation ...
s. * Non-combat aircraft are not designed for combat as their primary function, but may carry weapons for self-defense. Non-combat roles include search and rescue, reconnaissance, observation, transport, training, and

aerial refueling Aerial refueling, also referred to as air refueling, in-flight refueling (IFR), air-to-air refueling (AAR), and tanking, is the process of transferring aviation fuel from one military aircraft (the tanker) to another (the receiver) during flight ...

. These aircraft are often variants of civil aircraft. Most military aircraft are powered heavier-than-air types. Other types, such as gliders and balloons, have also been used as military aircraft; for example, balloons were used for observation during the

American Civil War The American Civil War (also known by other names) was a civil war in the United States from 1861 to 1865, fought between northern states loyal to the Union and southern states that had seceded to form the Confederate States of America. Th ...

and

World War I World War I or the First World War, often abbreviated as WWI or WW1, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously known as the Great War or "the war to end all wars", i ...

, and

military glider Military gliders (an offshoot of common gliders) have been used by the militaries of various countries for carrying troops (glider infantry) and heavy equipment to a combat zone, mainly during the Second World War. These engineless aircraft were to ...

s were used during

to land troops.

Civil

Civil aircraft divide into ''commercial'' and ''general'' types, however there are some overlaps.

Commercial aircraft An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an air ...

include types designed for scheduled and charter airline flights, carrying passengers,

mail The mail or post is a system for physically transporting postcards, letters, and parcels. A postal service can be private or public, though many governments place restrictions on private systems. Since the mid-19th century, national postal syste ...

and other

cargo In economics, the word cargo refers in particular to goods or produce being conveyed—generally for commercial gain—by water, air or land. "Freight" is the money paid to carry cargo. ''Cargo'' was originally a shipload. Cargo now covers ...

cargo

. The larger passenger-carrying types are the airliners, the largest of which are

wide-body aircraft A wide-body aircraft, also known as a twin-aisle aircraft, is an airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is . In the typical wide-body economy cabi ...

. Some of the smaller types are also used in

general aviation General aviation (GA) represents all civil aviation "aircraft operation other than a commercial air transport or an aerial work operation". Definition The International Civil Aviation Organization (ICAO) defines civil aviation aircraft ope ...

, and some of the larger types are used as VIP aircraft.

General aviation General aviation (GA) represents all civil aviation "aircraft operation other than a commercial air transport or an aerial work operation". Definition The International Civil Aviation Organization (ICAO) defines civil aviation aircraft ope ...

is a catch-all covering other kinds of

private Private or privates may refer to: Music * "In Private", by Dusty Springfield from the 1990 album ''Reputation'' * Private (band), a Denmark-based band * "Private" (Ryōko Hirosue song), from the 1999 album ''Private'', written and also recorded by ...

(where the pilot is not paid for time or expenses) and commercial use, and involving a wide range of aircraft types such as business jets (bizjets),

trainers Sneakers (also called trainers, athletic shoes, tennis shoes, gym shoes, kicks, sport shoes, flats, running shoes, skate shoes, or runners) are shoes primarily designed for sports or other forms of physical exercise but that are now also wide ...

homebuiltA hand-crafted, coal-fired, 1:8 scale 2-10-0 'live steam' locomotive in gauge, built in 14,000 hours over a period of 15 years. Homebuilt machines are machines built outside of specialised workshops or factories. This can include different things su ...

, gliders,

warbird A warbird is any vintage military aircraft now operated by civilian organizations and individuals or, in some instances, by historic arms of military forces, such as the Battle of Britain Memorial Flight, the RAAF Museum Historic Flight or the So ...

s and

s to name a few. The vast majority of aircraft today are general aviation types.

Experimental

An experimental aircraft is one that has not been fully proven in flight, or that carries a

Special Airworthiness Certificate A standard certificate of airworthiness is a permit for commercial passenger or cargo operation, issued for an aircraft by the national aviation authority in the state/nation in which the aircraft is registered. For other aircraft such as crop-spra ...

, called an Experimental Certificate in United States parlance. This often implies that the aircraft is testing new aerospace technologies, though the term also refers to amateur-built and kit-built aircraft, many of which are based on proven designs. MiniCeline ultralight aircraft

Model

A model aircraft is a small unmanned type made to fly for fun, for static display, for aerodynamic research or for other purposes. A

scale model A scale model is most generally a physical model of an object that maintains accurate relationships between its important aspects, although absolute values of the original properties need not be preserved. This enables it to demonstrate some beha ...

is a replica of some larger design.

References

External links

History

The Evolution of Modern Aircraft (NASA)

Smithsonian Air and Space Museum
nbsp;— Online collection with a particular focus on history of aircraft and spacecraft
Amazing Early Flying Machines
slideshow by ''

Life Life is a characteristic that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased (they have died), or because the ...

'' magazine

Information

Airliners.net

Aviation Dictionary
Free aviation terms, phrases and jargons
''New Scientist's'' Aviation page
{{Authority control

History

Methods of lift

Lighter than air – aerostats

Heavier-than-air – aerodynes

Fixed-wing

Rotorcraft

Other methods of lift

Scale, sizes and speeds

Sizes

Speeds

Propulsion

Unpowered aircraft

Powered aircraft

Propeller aircraft

Jet aircraft

Rotorcraft

Other types of powered aircraft

Design and construction

Structure

Aerostats

Aerodynes

Avionics

Flight characteristics

Flight envelope

Range

Flight dynamics

Stability

Control

Impacts of aircraft use

Uses for aircraft

Military

Civil

Experimental

Model

See also

Lists

Topics

References

External links

History

Information