An
aircraft is a
vehicleA vehicle is a mechanical means of conveyance, a carriage or transport. Most often they are manufactured , although some other means of transport which are not made by humans also may be called vehicles; examples include icebergs and floating tree trunks.Vehicles may be propelled or pulled by...
which is able to
flyFlight is the process by which an object moves either through the air, or movement beyond earth's atmosphere , by aerodynamically generating lift, propulsive thrust or aerostatically using buoyancy, or by simple ballistic movement.-Buoyant flight:Humans, although not apparently other animals, have...
by being supported by the air, or in general, the
atmosphereAn atmosphere is a layer of gases that may surround a material body of sufficient mass, by the gravity of the body, and are retained for a longer duration if gravity is high and the atmosphere's temperature is low...
of a planet. An aircraft counters the force of gravity by using either
static liftIn physics, buoyancy is the upward force that keeps things afloat. The net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body. This force enables the object to float or at least seem lighter....
(as with balloons, blimps and dirigibles) or by using the
dynamic liftA fluid flowing past the surface of a body exerts a force on it. Lift is defined to be the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is defined to be the component of the fluid-dynamic force parallel to the flow...
of an
airfoilAn airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
(as with vehicles that plane the air with wings in a straight manner, such as airplanes and gliders, or vehicles that generate lift with wings in a
rotary mannerA rotorcraft or rotary wing aircraft is a heavier-than-air flying machine that uses lift generated by wings, called rotor blades, that revolve around a mast. Several rotor blades mounted to a single mast are referred to as a rotor. The International Civil Aviation Organization defines a rotorcraft...
, such as helicopters or gyrocopters).
Although
rocketA rocket or rocket vehicle is a missile, spacecraft, aircraft or other vehicle which obtains thrust by the reaction of the rocket to the ejection of a jet of fast moving fluid exhaust from a rocket engine. Chemical rockets create their exhaust by the combustion of rocket propellant...
s and
missileA missile is a self-propelled projectile used as a weapon. Missiles are typically propelled by rockets or jet engines. Missiles generally have one or more explosive warheads, although other weapon types may also be used...
s also travel through the atmosphere, most are not considered aircraft because they use rocket thrust instead of aerodynamics as the primary means of lift (A
cruise missileA cruise missile is a guided missile that carries an explosive payload and uses a lifting wing and a propulsion system, usually a jet engine, to allow sustained flight; it is essentially a flying bomb. Cruise missiles are generally designed to carry a large conventional or nuclear warhead many...
may be considered to be an aircraft because it relies on a lifting wing).
The
humanHumans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving member of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving...
activity which surrounds aircraft is called
aviationAviation is the activity involving man-made air-borne flying devices , including the people, organizations, and regulatory bodies involved with them.- History :...
. Manned aircraft are flown by an onboard
pilotAn aviator is a person who flies aircraft for pleasure or as a profession. The first recorded use of the term was in 1887 as a variation of the French 'aviation', from the latin 'avis', coined 1863 by G. de la Landelle in "Aviation ou Navigation Aérienne"...
. Unmanned aerial vehicles may be
remotely controlledRemotely Piloted Vehicle is a term used by United States Department of Defense during the 70's and 80's to describe a robotic aircraft flown by a pilot located in a Ground Control Station...
or self-controlled by onboard computers.
Target droneA target drone is an unmanned, remote controlled aerial vehicle, usually used in the training of anti-aircraft crews.In its simplest form target drones often resemble radio controlled model aircraft...
s are an example of UAVs.
Lighter than air – aerostats
AerostatThe word aerostat was originally French and is derived from the Greek aer + statos . An aerostat is a lighter than air object that can stay stationary in the air. Aerostats include free balloons, airships, moored balloons and tethered Helikites...
s use
buoyancyIn physics, buoyancy is the upward force that keeps things afloat. The net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body. This force enables the object to float or at least seem lighter....
to float in the air in much the same way that ships float on the water. They are characterized by one or more large gasbags or canopies, filled with a relatively low density gas such as
heliumHelium is the chemical element with atomic number 2, and is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert monatomic gas that heads the noble gas group in the periodic table...
,
hydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H
2...
or
hot airThe hot air balloon is the oldest successful human-carrying flight technology and is a subset of balloon aircraft.On November 21, 1783, in Paris, France, the first manned flight was made by Jean-François Pilâtre de Rozier and François Laurent d'Arlandes in a hot air balloon created by the...
, 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 lanterns date back to the 3rd century BC, and were only the second type of aircraft to fly, the first being
kiteA kite is a flying tethered aircraft that depends upon the tension of a tethering system. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates...
s.
Originally, a
balloonA balloon is a type of aircraft that remains aloft due to its buoyancy. A balloon travels by moving with the wind. It is distinct from an airship, which is a buoyant aircraft that can be propelled through the air in a controlled manner....
was any aerostat, while the term
airshipAn airship or dirigible is a lighter-than-air aircraft that can be steered and propelled through the air using rudders and propellers or other thrust...
was used for large, powered aircraft designs – usually fixed-wing – 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
rigidA rigid airship was a type of airship in which the envelope retained its shape by the use of an internal structural framework rather than by being forced into shape by the pressure of the lifting gas within the envelope as used in blimps and semi-rigid airships.Rigid airships were produced and...
outer framework and separate aerodynamic skin surrounding the gas bags, were produced, the
ZeppelinFor the English rock group, please see Led Zeppelin. For other meanings please see Zeppelin .A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in 1893...
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 disasterThe Hindenburg disaster took place on Thursday 6 May 1937 as the LZ 129 Hindenburg caught fire and was destroyed within one minute while attempting to dock with its mooring mast at the Lakehurst Naval Air Station, which is located adjacent to the borough of Lakehurst in Manchester Township, New...
in 1937, led to the demise of these airships. Nowadays a "balloon" is an unpowered aerostat, whilst an "airship" is a powered one.
A powered, steerable aerostat is called a
dirigible. 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
blimpsA blimp, or non-rigid airship, is an airship without an internal supporting framework or keel. A non-rigid airship differs from a semi-rigid airship and a rigid airship in that it does not have any rigid structure, neither a complete framework nor a partial keel, to help the airbag maintain its...
. During the
Second World WarWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
, 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 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 liftAerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
, and
powered liftPowered lift or powered-lift refers to a type of aircraft that can take off and land vertically and functions differently from a rotorcraft in horizontal flight.-Definition:...
in the form of engine thrust.
Aerodynamic lift is the most common, with
fixed-wing aircraftA fixed-wing aircraft, usually called an airplane, aeroplane or plane, is an aircraft capable of flight using forward motion that causes air to pass over its wings to generate lift. Planes include jet engine and propeller driven vehicles propelled forward by thrust, as well as unpowered aircraft...
being kept in the air by the forward movement of wings, and
rotorcraftA rotorcraft or rotary wing aircraft is a heavier-than-air flying machine that uses lift generated by wings, called rotor blades, that revolve around a mast. Several rotor blades mounted to a single mast are referred to as a rotor. The International Civil Aviation Organization defines a rotorcraft...
by spinning wing-shaped rotors sometimes called rotary wings. A wing is a flat, horizontal surface, usually shaped in cross-section as an
aerofoilAn airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
. To fly, air must flow over the wing and generate
liftA fluid flowing past the surface of a body exerts a force on it. Lift is defined to be the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is defined to be the component of the fluid-dynamic force parallel to the flow...
. A
flexible wing is a wing made of fabric or thin sheet material, often stretched over a rigid frame. A
kiteA kite is a flying tethered aircraft that depends upon the tension of a tethering system. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates...
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
verticallyIn astronomy, geography, geometry and related sciences and contexts, a direction passing by a given point is said to be vertical if it is locally aligned with the gradient of the gravity field, i.e., with the direction of the gravitational force at that point.-Discussion:Although the word vertical...
downwards.
The
initialismAcronyms and initialisms are abbreviations that are formed using the initial components in a phrase or name. These components may be individual letters or parts of words . There is no universal agreement on the precise definition of the various terms , nor on written usage...
VTOLVTOL is an abbreviation for Vertical Take-Off and Landing aircraft. See also V/STOL. This classification includes fixed-wing aircraft that can hover, take off and land vertically as well as helicopters and other aircraft with powered rotors, such as tiltrotors...
(
vertical
take
off and
landing) is applied to aircraft that can take off and land vertically. Most are rotorcraft. Others, such as the Hawker Siddeley Harrier, take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. Similarly,
STOLSTOL is an acronym for short take-off and landing, a term used to describe aircraft with very short runway requirements.The formal NATO definition is:...
stands for
short
take
off and
landing. Some VTOL aircraft often operate in a
short
take
off/
vertical
landing mode known as
STOVLSTOVL is an acronym for Short Take Off and Vertical Landing.This is the ability of some aircraft to take off from a short runway or take off vertically if it does not have a very heavy payload and land vertically...
.
A pure
rocketA rocket or rocket vehicle is a missile, spacecraft, aircraft or other vehicle which obtains thrust by the reaction of the rocket to the ejection of a jet of fast moving fluid exhaust from a rocket engine. Chemical rockets create their exhaust by the combustion of rocket propellant...
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 which obtain aerodynamic lift at very high speed due to airflow over their bodies, are a marginal case.
Fixed-wing aircraft
Airplanes or
aeroplanes are technically called
fixed-wing aircraftA fixed-wing aircraft, usually called an airplane, aeroplane or plane, is an aircraft capable of flight using forward motion that causes air to pass over its wings to generate lift. Planes include jet engine and propeller driven vehicles propelled forward by thrust, as well as unpowered aircraft...
.
The forerunner of the fixed-wing aircraft is the
kiteA kite is a flying tethered aircraft that depends upon the tension of a tethering system. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates...
. 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
windWind is the flow of air or other gases that compose an atmosphere . On Earth, wind consists of the bulk movement of air...
blowing over its wings to provide lift. Kites were the first kind of aircraft to fly, and were invented in
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
around 500 BC. Much aerodynamic research was done with kites before test aircraft, wind tunnels and computer modelling programs became available.
The first heavier-than-air craft capable of controlled free flight were gliders. A
gliderGlider aircraft are heavier-than-air craft that are supported in flight by the dynamic reaction of the air against their lifting surfaces, and whose free flight does not depend on an engine...
designed by
CayleySir George Cayley, 6th Baronet was a prolific English engineer, one of the most important people in the history of aeronautics. Many consider him the first true scientific aerial investigator and first person to understand the underlying principles and forces of flight...
carried out the first true manned, controlled flight in 1853.
Besides the method of propulsion, fixed-wing aircraft are generally characterized by their
wing configurationThis article summarises the wing configurations of fixed-wing aircraft, popularly called aeroplanes, airplanes or just planes.Sometimes the distinction between types is blurred, for example the wings of many modern combat aircraft may be described either as cropped compound deltas with swept...
. The most important wing characteristics are:
- Number of wings – Monoplane
A monoplane is an aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...
, biplaneA biplane is a fixed-wing aircraft with two main wings. The Wright brothers' Wright Flyer used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing...
, etc.
- Wing support – Braced or cantilever, rigid or flexible.
- Wing planform – including aspect ratio
The aspect ratio of a shape is the ratio of its longer dimension to its shorter dimension. It may be applied to two characteristic dimensions of a three-dimensional shape, such as the ratio of the longest and shortest axis, or for symmetrical objects that are described by just two measurements,...
, angle of sweepA swept wing is a wing planform with a wing root to wingtip direction angled beyond the spanwise axis, generally used to delay the drag rise caused by fluid compressibility. Swept wings provide lateral stability and it was for this reason that the concept was first employed in the designs of...
and any variations along the span (including the important class of delta wingThe delta wing is a wing planform in the form of a triangle, named after the Greek uppercase delta which is a triangle .Conception of this wing and its name have been suggested in the 17th century by Polish inventor Kazimierz Siemienowicz. Its use in the so called "tailless delta", i.e...
s).
- Location of the horizontal stabiliser, if any.
- Dihedral angle – positive, zero or negative (anhedral).
A
variable geometryVariable geometry may refer to:* Various different ways to alter the shape of an aircraft's wings in flight in order to alter their aerodynamic properties: Variable-sweep wings or 'swing wings', variable camber wings, variable-incidence wings, and Oblique wings.* Multi-speed Europe, a proposed...
aircraft can change its wing configuration during flight.
A
flying wingA flying wing is a fixed-wing aircraft which has no definite fuselage, with most of the crew, payload and equipment being housed inside the main wing structure....
has no fuselage, though it may have small blisters or pods. The opposite of this is a
lifting bodyThe lifting body is an aircraft configuration where the body itself produces lift. It is related to flying wing which is a wing without a conventional fuselage. A lifting body is a fuselage that generates lift without the shape of a typical thin and flat wing structure. A flying wing seeks to...
which has no wings, though it may have small stabilising and control surfaces.
Most fixed-wing aircraft feature a tail unit or
empennageEmpennage is an aviation term used to describe the tail portion of an aircraft. The empennage is also known as the tail or tail assembly; all three terms may be interchangeably used. The empennage gives stability to the aircraft and controls the flight dynamics of pitch and yaw...
incorporating vertical, and often horizontal, stabilising surfaces.
SeaplaneA seaplane is a fixed-wing aircraft capable of taking off and landing on water. Seaplanes are usually divided into two categories: floatplanes and flying boats...
s are aircraft that land on water, and they fit into two broad classes:
Flying boatA flying boat, properly known as an aquatic plane, is a specialised form of aircraft that is designed to take off from and land on water, using its fuselage as a floating hull. Such aircraft are sometimes stabilised on water by underwing floats or by wing-like projections from the fuselage...
s are supported on the water by their
fuselageThe fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
. A float plane's fuselage remains clear of the water at all times, the aircraft being supported by two or more floats attached to the fuselage and/or wings. Some examples of both
flying boatA flying boat, properly known as an aquatic plane, is a specialised form of aircraft that is designed to take off from and land on water, using its fuselage as a floating hull. Such aircraft are sometimes stabilised on water by underwing floats or by wing-like projections from the fuselage...
s and float planes are
amphibiousAn amphibious or amphibian aircraft is an aircraft that can take off and land on either land or water. Amphibious aircraft are typically flying boats and floatplanes with retractable wheels.-Design:...
, being able to take off from and alight on both land and water.
Some people consider wing-in-ground-effect vehicles to be fixed-wing aircraft, others do not. These craft "fly" close to the surface of the ground or water. An example is the Russian ekranoplan (nicknamed the "Caspian Sea Monster"). Man-powered aircraft also rely on ground effect to remain airborne, but this is only because they are so underpowered—the airframe is theoretically capable of flying much higher.
Rotorcraft
Rotorcraft, or rotary-wing aircraft, use a spinning rotor with
aerofoilAn airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
section blades (a
rotary wing) to provide lift. Types include
helicopterA helicopter is an aircraft that is lifted and propelled by one or more horizontal rotors, each rotor consisting of two or more rotor blades. Helicopters are classified as rotorcraft or rotary-wing aircraft to distinguish them from fixed-wing aircraft because the helicopter achieves lift with the...
s,
autogyroAn autogyro, also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which utilises an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust...
s and various hybrids such as gyrodynes and compound rotorcraft.
HelicopterA helicopter is an aircraft that is lifted and propelled by one or more horizontal rotors, each rotor consisting of two or more rotor blades. Helicopters are classified as rotorcraft or rotary-wing aircraft to distinguish them from fixed-wing aircraft because the helicopter achieves lift with the...
s have powered rotors. The rotor is driven (directly or indirectly) by an engine and pushes air downwards to create lift. By tilting the rotor forwards, the downwards flow is tilted backwards, producing thrust for forward flight.
AutogyroAn autogyro, also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which utilises an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust...
s or
gyroplanes have unpowered rotors, with a separate power plant to provide thrust. The rotor is tilted backwards. As the autogyro moves forward, air blows upwards through it, making it spin.(cf.
AutorotationIn aviation, the word autorotation is applied to operation of fixed-wing aircraft and rotary-wing aircraft. The word has significantly different meanings in each of these two applications....
)
This spinning dramatically increases the speed of airflow over the rotor, to provide lift.
Juan de la CiervaJuan De la Cierva was a Spanish Civil Engineer and pilot. His most famous accomplishment was the invention in 1920 of the Autogiro, a single-rotor type of aircraft that came to be called autogyro in the English language...
(a Spanish civil engineer) used the product name
autogiro, and
BensenThe Bensen Aircraft Corporation was established by Dr Igor Bensen at Raleigh-Durham International Airport in North Carolina in 1952 to develop and market a variety of helicopters and autogyros of Bensen's own design....
used
gyrocopter.
Rotor kites, such as the
Focke Achgelis Fa 330The Focke Achgelis FA 330 Bachstelze was a type of rotary-wing kite, known as a gyroglider or rotor kite. They were towed behind German U-boats during World War II to allow a lookout to see farther, giving the submarines a better chance of escape in a war that was becoming increasingly dangerous...
are unpowered autogyros, which must be towed by a tether to give them forward ground speed or else be tether-anchored to a static anchor in a high-wind situation for kited flight.
Gyrodynes are a form of helicopter, where forward thrust is obtained from a separate propulsion device rather than from tilting the rotor. The definition of a 'gyrodyne' has changed over the years, sometimes including equivalent autogyro designs. The most important characteristic is that in forward flight air does not flow significantly either up or down through the rotor disc but primarily across it. The
Heliplane is a similar idea.
Compound rotorcraft have wings which provide some or all of the lift in forward flight. Compound helicopters and compound autogyros have been built, and some forms of gyroplane may be referred to as compound gyroplanes.
TiltrotorA tiltrotor aircraft utilizes a pair or more of powered rotors mounted on rotating shafts or nacelles at the end of a fixed wing for lift and propulsion, and combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft...
aircraft (such as the
V-22 OspreyThe Bell-Boeing V-22 Osprey is a multi-mission, military, tiltrotor aircraft with both a vertical takeoff and landing and short takeoff and landing capability. It is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop...
) have their rotors horizontal for vertical flight, and pivot the rotors vertically like a
propellerA propeller is a type of fan which transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and air or water is accelerated behind the blade...
for forward flight. The
ColeopterA coleopter is a type of Vertical Take-Off and Landing aircraft design where the fuselage is surrounded by an annular wing. The aircraft is intended to take off and land on its tail...
had a cylindrical wing forming a duct around the rotor. On the ground it sat on its tail, and took off and landed vertically like a helicopter. The whole aircraft would then have tilted forward to fly as a propeller-driven fixed-wing aircraft using the duct as a wing (though this transition was never achieved in practice.)
Some rotorcraft have reaction-powered rotors with gas jets at the tips, but most have one or more lift rotors powered from engine-driven shafts.
Other methods of lift
- A lifting body
The lifting body is an aircraft configuration where the body itself produces lift. It is related to flying wing which is a wing without a conventional fuselage. A lifting body is a fuselage that generates lift without the shape of a typical thin and flat wing structure. A flying wing seeks to...
is the opposite of a flying wingA flying wing is a fixed-wing aircraft which has no definite fuselage, with most of the crew, payload and equipment being housed inside the main wing structure....
. In this configuration the aircraft body is 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-24The X-24 was an experimental US aircraft developed from a joint USAF-NASA program named PILOT . It was designed and built to test lifting body concepts, experimenting with the concept of unpowered reentry and landing, later used by the Space Shuttle.-X-24A Development:The X-24 was one of a group of...
, which led up to the Space ShuttleThe Space Shuttle, part of the Space Transportation System , is a spacecraft operated by NASA for orbital human spaceflight missions. It began operations in the 1980s and is scheduled to be retired from service in 2010 after 134 launches...
were lifting bodies (though the shuttle itself is not), and some supersonicThe term supersonic is used to define a speed that is over the speed of sound . In dry air at 20 °C , the threshold value required for an object to be traveling at a supersonic speed is approximately 343 m/s, . Speeds greater than 5 times the speed of sound are often referred to as hypersonic...
missileA missile is a self-propelled projectile used as a weapon. Missiles are typically propelled by rockets or jet engines. Missiles generally have one or more explosive warheads, although other weapon types may also be used...
s obtain lift from the airflow over a tubular body.
- Powered lift
Powered lift or powered-lift refers to a type of aircraft that can take off and land vertically and functions differently from a rotorcraft in horizontal flight.-Definition:...
types rely on engine-derived lift for vertical takeoff and landing (VTOLVTOL is an abbreviation for Vertical Take-Off and Landing aircraft. See also V/STOL. This classification includes fixed-wing aircraft that can hover, take off and land vertically as well as helicopters and other aircraft with powered rotors, such as tiltrotors...
). Most types transition to fixed-wing lift for horizontal flight. Classes of powered lift types include VTOLVTOL is an abbreviation for Vertical Take-Off and Landing aircraft. See also V/STOL. This classification includes fixed-wing aircraft that can hover, take off and land vertically as well as helicopters and other aircraft with powered rotors, such as tiltrotors...
jet aircraft (such as the Harrier jump-jet) and tiltrotors (such as the V-22 OspreyThe Bell-Boeing V-22 Osprey is a multi-mission, military, tiltrotor aircraft with both a vertical takeoff and landing and short takeoff and landing capability. It is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop...
), among others. A few examples rely entirely on engine thrust to provide lift throughout the flight. There are few practical applications. Experimental designs have been built for personal fan-lift hover platforms and jetpacks or for VTOLVTOL is an abbreviation for Vertical Take-Off and Landing aircraft. See also V/STOL. This classification includes fixed-wing aircraft that can hover, take off and land vertically as well as helicopters and other aircraft with powered rotors, such as tiltrotors...
research (for example the flying bedsteadThe Flying Bedstead was a nickname given to two different experimental vertical take-off and landing aircraft, both receiving the nickname because each comprised a skeletal platform raised on four legs that resembled a bedstead....
).
- The FanWing
FanWing or fan wing is a concept for a type of aircraft. It is distinct from existing types of aircraft such as airplanes and helicopters in that it uses a fixed wing with a forced airflow produced by cylindrical fans mounted above the wing....
is a recent innovation and represents a completely new class of aircraft. This uses a fixed wing with a cylindrical fan mounted spanwise just above. As the fan spins, it creates an airflow backwards over the upper surface of the wing, creating lift. The fan wing is (2005) in development in the United KingdomThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
.
Gliders
Heavier-than-air unpowered aircraft such as
gliderUnpowered aircraft are a group of aerial vehicles that can fly without propulsion. They can be classified as gliders, balloons and kites. In this instance, 'flight' means a trajectory that is not merely a vertical descent such as a parachute. In the case of kites, the flight is not free, but...
s (i.e. sailplanes), hang gliders and paragliders, and other gliders usually do not employ propulsion once airborne. Take-off may be by launching forwards and downwards from a high location, or by pulling into the air on a tow-line, 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). Some gliders can 'soar'- gain height from updrafts such as thermal currents. The first practical, controllable example was designed and built by the British scientist and pioneer
George CayleySir George Cayley, 6th Baronet was a prolific English engineer, one of the most important people in the history of aeronautics. Many consider him the first true scientific aerial investigator and first person to understand the underlying principles and forces of flight...
, who many recognise as the first aeronautical engineer.
Balloons
Balloons 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.
Kites
Kites are aircraft that are tethered to the ground or other object (fixed or mobile) that maintains tension in the tether or
kite lineKites have a wing and a kite line , or sometimes more than one line. Kite systems may have more than one kite and more than one kite line. Solar kites have a gravity mass-less line; but the most common type of kite line has mass; the kite line may be flexible or rigid as in a contemporary speed...
; they rely on virtual or real wind blowing over and under them to generate lift and drag. Kytoons are balloon kites that are shaped and tethered to obtain kiting deflections, and can be lighter-than-air, neutrally buoyant, or heavier-than air.
Propeller aircraft
A
propellerA propeller is a type of fan which transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and air or water is accelerated behind the blade...
comprises a set of small, wing-like aerofoils set around a central hub which spins on an axis aligned in the direction of travel. Spinning the propeller creates aerodynamic lift, or thrust, in a forward direction. A
contra-prop arrangement has a second propeller close behind the first one on the same axis, which rotates in the opposite direction.
A
tractor design mounts the propeller in front of the power source, and a
pusher design mounts it behind. Although the pusher design allows cleaner airflow over the wing, tractor configuration is more common because it allows cleaner airflow to the propeller and provides a better weight distribution.
A variation on the propeller is to use many broad blades to create a fan. Such fans are traditionally surrounded by a ring-shaped fairing or duct, as
ducted fans.
Many kinds of power plant have been used to drive propellers.
The earliest designs used man power to give dirigible balloons some degree of control, and go back to
Jean-Pierre BlanchardJean-Pierre Blanchard was a French inventor, most remembered as a pioneer in aviation and ballooning.-Biography:...
in 1784. Attempts to achieve heavier-than-air man-powered flight did not succeed until
Paul MacCreadyPaul B. MacCready, Jr. was an American aeronautical engineer. He was the founder of AeroVironment and the inventor of the first practical flying machine powered by a human being...
's
Gossamer CondorThe Gossamer Condor was the first human-powered aircraft capable of controlled and sustained flight, able to win the Kremer prize.-History:...
in 1977.
The first powered flight was made in a
steam-poweredSteam aircraft are aircraft that are propelled by steam engines. They were unusual devices because of the difficulty in producing a powerplant with a high enough power to weight ratio to be practical...
dirigible by
Henri GiffardHenri Giffard was a French engineer.Giffard invented the injector and the powered airship with a steam engine weighing over 180 kg ; it was the world's first passenger-carrying airship . Both practical and steerable, the hydrogen-filled airship was equipped with a 3 hp steam engine that drove a...
in 1852. Attempts to marry a practical lightweight
steam engineA steam engine is a heat engine that performs mechanical work using steam as its working fluid.The idea of using boiling water to produce mechanical motion has a long history, going back about 2000 years...
to a practical fixed-wing airframe did not succeed until much later, by which time the internal combustion engine was already dominant.
From the first controlled powered fixed-wing aircraft flight by the
Wright brothersThe Wright brothers, Orville and Wilbur , were two Americans who are generally credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903...
until
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
, propellers turned by the
internal combustion piston engineThe internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine the expansion of the high temperature and pressure gases, which are produced by the combustion, directly applies force to a movable...
were virtually the only type of propulsion system in use. (See also:
Aircraft engineAn aircraft engine is a propulsion system for an aircraft. Aircraft engines are almost always either lightweight piston engines or gas turbines. This article is an overview of the basic types of aircraft engines and the design concepts employed in engine development for aircraft.- Engine design...
.) The piston engine is still used in the majority of smaller aircraft produced, since it is efficient at the lower altitudes and slower speeds suited to propellers.
Turbine engines need not be used as jets (see below), but may be geared to drive a propeller in the form of a
turbopropTurboprop engines are a type of aircraft powerplant that use a gas turbine to drive a propeller. The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
. Modern helicopters also typically use turbine engines to power the rotor. Turbines provide more power for less weight than piston engines, and are better suited to small-to-medium size aircraft or larger, slow-flying types. Some turboprop designs (see below) mount the propeller directly on an engine shaft, and are called
propfanAn unducted fan or propfan is a modified turbofan engine, with the fan placed outside of the engine nacelle on the same axis as the compressor blades. Propfans are also known as ultra-high bypass engines and, most recently, open rotor jet engines...
s.
Since the 1940s, propellers and propfans with swept tips or curved "scimitar-shaped" blades have been studied for use in high-speed applications so as to delay the onset of shockwaves, in similar manner to wing sweepback, where the blade tips approach the speed of sound. The
Airbus A400M turboprop transport aircraft is expected to provide the first production example: note that it is not a propfan because the propellers are not mounted direct on the engine shaft but are driven through reduction gearing.
Other less common power sources include:
- Electric motors, often linked to solar panels to create a solar-powered aircraft.
- Rubber bands, wound many times to store energy, are mostly used for flying models.
Jet aircraft
Air-breathing
jet engineA jet engine is a reaction engine that discharges a fast moving jet of fluid to generate thrust in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and pump-jets...
s provide thrust by taking in air, burning it with fuel in a
combustion chamber-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber. This pressure can be used to do work, for example, to move a piston on a crankshaft or a turbine...
, and accelerating the exhaust rearwards so that it ejects at high speed. The reaction against this acceleration provides the engine thrust.
Jet engines can provide much higher thrust than propellers, and are naturally efficient at higher altitudes, being able to operate above . They are also much more fuel-efficient at normal flight speeds than
rocketA rocket or rocket vehicle is a missile, spacecraft, aircraft or other vehicle which obtains thrust by the reaction of the rocket to the ejection of a jet of fast moving fluid exhaust from a rocket engine. Chemical rockets create their exhaust by the combustion of rocket propellant...
s. Consequently, nearly all high-speed and high-altitude aircraft use jet engines.
The early
turbojetTurbojets are the oldest kind of general purpose jet engines. Two engineers, Frank Whittle in the United Kingdom and Hans von Ohain in Germany, developed the concept independently into practical engines during the late 1930s, although credit for the first turbojet is given to Whittle who submitted...
and modern
turbofanA turbofan is a type of aircraft gas turbine engine that provides propulsion using a combination of a ducted fan and a jet exhaust nozzle. Part of the airstream from the ducted fan passes through the core, providing oxygen to burn fuel to create power. However, the rest of the air flow bypasses...
use a spinning turbine to create airflow for takeoff and to provide thrust. Many, mostly in military aviation, use afterburners which inject extra fuel into the exhaust.
Use of a turbine is not absolutely necessary: other designs include the crude
pulse jetA pulse jet engine is a very simple type of jet engine in which combustion occurs in pulses. Pulsejet engines can be made with few or no moving parts, and are capable of running statically....
, high-speed
ramjetA ramjet, sometimes referred to as a stovepipe jet, or an athodyd, is a form of jet engine using the engine's forward motion to compress incoming air, without a rotary compressor...
and the still-experimental supersonic-combustion ramjet or
scramjetA scramjet is a variation of a ramjet distinguished by supersonic combustion. A scramjet, like a ramjet, essentially consists of a constricted tube through which inlet air is compressed by the high speed of the vehicle, a combustion chamber where fuel is combusted, and a nozzle through which the...
. These designs require an existing airflow to work and cannot work when stationary, so they must be launched by a catapult or rocket booster, or dropped from a mother ship.
The bypass turbofan engines of the
Lockheed SR-71The Lockheed SR-71 is an advanced, long-range, Mach 3 strategic reconnaissance aircraft developed from the Lockheed A-12 and YF-12A aircraft by the Lockheed Skunk Works as a Black project. The SR-71 was unofficially named the Blackbird, and called the Habu by its crews, referring to an Okinawan...
were a hybrid design – the aircraft took off and landed in jet turbine configuration, and for high-speed flight the afterburner was lit and the turbine bypassed, to create a ramjet.
The
motorjetA 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. At the heart the motorjet is always an ordinary piston engine , but instead of this driving a propeller, it drives...
was a very early design which used a piston engine in place of the combustion chamber, similar to a
turbochargedA turbocharger, or turbo, is a gas compressor that is used for forced-induction of an internal combustion engine. A form of supercharger, the purpose of a turbocharger is to increase the density of air entering the engine to create more power...
piston engine except that the thrust is derived from the turbine instead of the crankshaft. It was soon superseded by the turbojet and remained a curiosity.
Helicopters
The rotor of a helicopter, may, like a propeller, be powered by a variety of methods such as an internal-combustion engine or jet turbine. Tip jets, fed by gases passing along hollow rotor blades from a centrally mounted engine, have been experimented with. Attempts have even been made to mount engines directly on the rotor tips.
Helicopters obtain forward propulsion by angling the rotor disc so that a proportion of its lift is directed forwards to provide thrust.
Other forms of propulsion
- Rocket-powered aircraft
A rocket-powered aircraft or rocket plane is an aircraft that uses a rocket for propulsion, sometimes in addition to airbreathing jet engines. Rocket planes can achieve much higher speeds than similarly-sized jet aircraft, but typically for at most a few minutes of powered operation, followed by a...
have occasionally been experimented with, and the Messerschmitt KometThe Messerschmitt Me 163 Komet, designed by Alexander Martin Lippisch, was a German rocket-powered fighter aircraft. It was the only operational rocket-powered fighter aircraft to date. It was a revolutionary design, capable of performance unrivaled at the time.Messerschmitt test pilot Rudy Opitz...
fighter even saw action in the Second World War. Since then they have been restricted to rather specialised niches, such as the Bell X-1The Bell X-1, originally designated XS-1, was a joint NACA-U.S. Army Air Forces/US Air Force supersonic research project and the first aircraft to exceed the speed of sound in controlled, level flight...
which broke the sound barrier or the North American X-15The North American X-15 rocket-powered aircraft was part of the X-series of experimental aircraft, initiated with the Bell X-1, that were made for the USAF, NASA, and the USN. The X-15 set speed and altitude records in the early 1960s, reaching the edge of outer space and returning with valuable...
which travelled up into space where no oxygen is available for combustion (rockets carry their own oxidant). Rockets have more often been used as a supplement to the main powerplant, typically to assist takeoff of heavily loaded aircraft, but also in a few experimental designs such as the Saunders-Roe SR.53The Saunders-Roe SR.53 was a prototype interceptor aircraft of mixed jet and rocket propulsion developed for the Royal Air Force in the early 1950s...
to provide a high-speed dash capability.
- The flapping-wing ornithopter
An ornithopter 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 usually built on the same scale as these flying creatures...
is a category of its own. These designs may have potential, but no practical device has been created beyond research prototypes, simple toys, and a model hawk used to freeze prey into stillness so that it can be captured.
Classification by use
The major distinction in aircraft types is between
military aircraftA military aircraft is any fixed-wing or rotary-wing aircraft that is in the current employ of a military power. Fixed-wing military aircraft are also known as Warplanes....
, which includes not just combat types but many types of supporting aircraft, and
civil aircraftCivil 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 and work together to establish common standards and recommended practices...
, which include all non-military types.
Military aircraft
Combat aircraft divide broadly into
fightersA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
and
bomberA bomber is a military aircraft designed to attack ground and sea targets, primarily by dropping bombs on them.-Classifications of bombers:...
s, with several in-between types such as fighter-bombers and ground-attack aircraft (including
attack helicopterAn attack helicopter is a military helicopter specifically designed and built to carry weapons for attacking targets on the ground, such as enemy infantry, armored vehicles and structures. Weapons used on attack helicopters can include autocannons, machine-guns, rockets, and guided missiles such...
s).
Other supporting roles are carried out by specialist patrol, search and rescue, reconnaissance, observation, transport, training and
TankerAerial refueling, also called air refueling, in-flight refueling , air-to-air refueling or tanking, is the process of transferring fuel from one aircraft to another during flight. Applied to helicopters, it is known as HAR for Helicopter Aerial Refueling...
aircraft among others.
Many civil aircraft, both fixed-wing and rotary, have been produced in separate models for military use, such as the civil
Douglas DC-3The Douglas DC-3 is an American fixed-wing, propeller-driven aircraft whose speed and range revolutionized air transport in the 1930s and 1940s. Because of its lasting impact on the airline industry and World War II it is generally regarded as one of the most significant transport aircraft ever made...
airliner, which became the military
C-47The Douglas C-47 Skytrain or Dakota is a military transport aircraft that was developed from the Douglas DC-3 airliner. It was used extensively by the Allies during World War II and remained in front line operations through the 1950s with a few remaining in operation to this day.-Design and...
/C-53/R4D transport in the U.S. military and the "Dakota" in the UK and the
CommonwealthThe Commonwealth of Nations, often referred to as the Commonwealth and previously as the British Commonwealth, is an intergovernmental organisation of fifty-three independent member states. Most of them were formerly part of the British Empire. They co-operate within a framework of common values...
. Even the small fabric-covered two-seater
Piper J3 CubThe Piper J-3 Cub is a small, simple, light aircraft that was built between 1937 and 1947 by Piper Aircraft. With tandem seating, it was intended for flight training but became one of the most popular and best-known light aircraft of all time...
had a military version, the L-4 liaison, observation and trainer aircraft.
GliderMilitary gliders have been used by the military of various countries for carrying troops and heavy equipment to a combat zone, mainly during the Second World War...
s and
balloonA balloon is an inflatable flexible bag filled with a type of gas, such as helium, hydrogen, nitrous oxide or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were sometimes made of dried animal bladders...
s have also been used as military aircraft; for example, balloons were used for observation during the
American Civil WarThe American Civil War , also known as the War Between the States and several other names, was a civil war in the United States of America. Eleven Southern slave states declared their secession from the United States and formed the Confederate States of America...
and
World War IWorld War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
, and
military gliderMilitary gliders have been used by the military of various countries for carrying troops and heavy equipment to a combat zone, mainly during the Second World War...
s were used during
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
to land troops.
Civil aircraft
Civil aircraftCivil 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 and work together to establish common standards and recommended practices...
divide into
commercial and
general types, however there are some overlaps.
Commercial aircraft
Commercial aircraftCommercial aviation is the part of civil aviation that involves operating aircraft for hire...
include types designed for scheduled and charter
airlineAn airline provides air transport services for passengers or freight, generally with a recognized operating certificate or license. Airlines lease or own their aircraft with which to supply these services and may form partnerships or alliances with other airlines for mutual benefit.Airlines vary...
flights, carrying both passengers and cargo. The larger passenger-carrying types are often referred to as
airlinerAn airliner is a large fixed-wing aircraft for transporting passengers and cargo. Such planes are owned by airlines....
s, the largest of which are
wide-body aircraftA wide-body aircraft is a large airliner with two passenger aisles, also known as a twin-aisle aircraft. The typical fuselage diameter is . In the typical widebody economy cabin, passengers are seated seven to ten abreast, allowing a total capacity of 200 to 600 passengers...
. Some of the smaller types are also used in
general aviationGeneral aviation is one of two categories of civil aviation. It refers to all flights other than military and scheduled airline flights, both private and commercial. General aviation flights range from gliders and powered parachutes to large, non-scheduled cargo jet flights...
, and some of the larger types are used as VIP aircraft.
General aviation
General aviationGeneral aviation is one of two categories of civil aviation. It refers to all flights other than military and scheduled airline flights, both private and commercial. General aviation flights range from gliders and powered parachutes to large, non-scheduled cargo jet flights...
is a catch-all covering other kinds of private and commercial use, and involving a wide range of aircraft types such as
business jets (bizjets)Business jet, private jet or, colloquially, bizjet is a term describing a jet aircraft, usually of smaller size, designed for transporting groups of business people or wealthy individuals. Business jets may be adapted for other roles, such as the evacuation of casualties or express parcel...
,
trainersA trainer is an aircraft used to develop piloting, navigational or war-fighting skills in flight crew.Civilian pilots are normally trained in a light aircraft, with 2 or more seats to allow for student and instructor. The aircraft may be modified to withstand the flight conditions imposed by...
,
homebuiltAlso known as amateur-built aircraft or kit planes, homebuilt aircraft are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch," from plans, or from assembly kits....
,
aerobatic typesAerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in normal flight. Aerobatics are performed in airplanes and gliders for training, recreation, entertainment and sport...
,
racersthumb|250px|A pair of Sport Class racers passing the finish pylon at the Reno AirRaces.Air racing is a sport that involves small aircraft.- History :...
,
gliderUnpowered aircraft are a group of aerial vehicles that can fly without propulsion. They can be classified as gliders, balloons and kites. In this instance, 'flight' means a trajectory that is not merely a vertical descent such as a parachute. In the case of kites, the flight is not free, but...
s,
warbirdWarbird is a term used to describe vintage military aircraft. Although the term originally implied piston driven aircraft from the World War II era, it is now often extended to include all military aircraft, including jet powered aircraft, that are no longer in military service...
s,
firefightersAerial firefighting is the use of aircraft and other aerial resources to combat wildfires. The types of aircraft used include fixed-wing aircraft and helicopters. Smokejumpers and rappellers are also classified as aerial firefighters, delivered to the fire by parachute from a variety of fixed-wing...
,
medical transportsMedical evacuation, often termed MEDEVAC or medivac, is the timely and efficient movement and en route care provided by medical personnel to the wounded being evacuated from the battlefield or to injured patients being evacuated from the scene of an accident to receiving medical facilities using...
, and
cargoA cargo aircraft plane is a fixed-wing aircraft designed or converted for the carriage of goods, rather than passengers. They are usually devoid of passenger amenities, and generally feature one or more large doors for the loading and unloading of cargo...
transports, to name a few. The vast majority of aircraft today are general aviation types.
Within general aviation, there is a further distinction between
private aviationPrivate aviation is the part of civil aviation that involves flying not for hire. In most countries, private flights are always general aviation flights, but the opposite is not true: many general aviation flights are commercial in that the pilot is hired and paid...
(where the pilot is not paid for time or expenses) and commercial aviation (where the pilot is paid by a client or employer). The aircraft used in private aviation are usually light passenger, business, or recreational types, and are usually owned or rented by the pilot. The same types may also be used for a wide range of commercial tasks, such as flight training, pipeline surveying, passenger and freight transport, policing, crop dusting, and medical evacuations. However the larger, more complex aircraft are more likely to be found in the commercial sector.
For example, piston-powered propeller aircraft (single-engine or twin-engine) are common for both private and commercial general aviation, but for aircraft such as turboprops like the
Beechcraft King AirThis article is about 90 and 100 Series King Airs. For 200 and 300 Series King Airs, see the Beechcraft Super King Air article.The Beechcraft King Air family is part of a line of twin-turboprop aircraft produced by the Beech Aircraft Corporation...
and helicopters like the
Bell JetRangerThe Bell 206 is a family of two-bladed, single- or twin-engine helicopters, manufactured by Bell Helicopter at its Mirabel, Quebec plant. Originally developed for the United States Army's Light Observation Helicopter program, the 206 failed to be selected. Bell redesigned the airframe and...
, there are fewer private owners than commercial owners. Conventional business jets are most often flown by paid pilots, whereas the new generation of smaller jets are being produced for private pilots.
Experimental aircraft
Experimental aircraftIn generic use, an experimental aircraft is an aircraft that has not yet been fully proven in flight. Often, this implies that new aerospace technologies are being tested on the aircraft, though the label is more broad. Experimental aircraft is also a specific term referring to an aircraft flown...
are one-off specials, built to explore some aspect of aircraft design and with no other useful purpose. The
Bell X-1The Bell X-1, originally designated XS-1, was a joint NACA-U.S. Army Air Forces/US Air Force supersonic research project and the first aircraft to exceed the speed of sound in controlled, level flight...
rocket plane, which first broke the sound barrier in level flight, is a famous example.
The formal designation of "experimental aircraft" also includes other types which are "not certified for commercial applications", including one-off modifications of existing aircraft such as the
modified Boeing 747The Shuttle Carrier Aircraft are two extensively modified Boeing 747 airliners that NASA uses to transport Space Shuttle orbiters...
which NASA uses to ferry the space shuttle from landing site to launch site, and aircraft
homebuiltAlso known as amateur-built aircraft or kit planes, homebuilt aircraft are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch," from plans, or from assembly kits....
by amateurs for their own personal use.
Model aircraft
A
model aircraftModel aircraft are flying or non-flying models of existing or imaginary aircraft, often scaled down versions of full size planes, using materials such as balsa wood, foam and fiberglass. Designs range from simple gliders, to accurate scale models, some of which can be very large.Models may be built...
is a small unmanned type made to fly for fun, for static display, for aerodynamic research (cf
Reynolds numberIn fluid mechanics, the Reynolds number is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions...
) or for other purposes. A
scale modelA scale model is a representation or copy of an object that is larger or smaller than the actual size of the object . Very often the scale model is smaller than the original and used as a guide to making the object in full size...
is a replica of some larger design.
History
See also:
Timeline of aviationThis is a timeline of aviation history, and a list of more detailed aviation timelines.*Timeline of aviation - pre-18th century*Timeline of aviation - 18th century*Timeline of aviation - 19th century*Timeline of aviation - 20th century...
The history of aircraft development divides broadly into five eras:
- Pioneers of flight
- First World War
World War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
- The Golden Age
- Second World War
World War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
- Postwar era, also called the jet age
The Jet Age is a period of history defined by the social change brought about by the advent of large aircraft powered by turbine engines. These aircraft are able to fly much higher, faster, and farther than older piston-powered propliners, making transcontinental and inter-continental travel...
Manufacturers and types
Within any general category, aircraft are usually listed according to manufacturer and production type.
- See also: List of aircraft
Lists
Topics
External links
History
Information