Aeroplane
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An airplane or aeroplane (informally plane) is a
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 distinc ...
that is propelled forward by
thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...
from a
jet engine A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term ...
,
propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
, or
rocket engine A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordanc ...
. Airplanes come in a variety of sizes, shapes, and
wing configuration The wing configuration of a fixed-wing aircraft (including both glider (aircraft), gliders and powered aeroplanes) is its arrangement of lifting and related surfaces. Aircraft designs are often classified by their wing configuration. For examp ...
s. The broad spectrum of uses for airplanes includes
recreation Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...
,
transportation Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipeline, ...
of goods and people,
military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
, and
research Research is "creativity, creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular att ...
. Worldwide,
commercial aviation Commercial aviation is the part of civil aviation that involves operating aircraft for remuneration or hire, as opposed to private aviation. Definition Commercial aviation is not a rigorously defined category. All commercial air transport and ae ...
transports more than four billion passengers annually on
airliner 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 ...
s and transports more than 200 billion
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
-
kilometer The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ex ...
sMeasured in RTKs—an RTK is one tonne of revenue freight carried one kilometer. of cargo annually, which is less than 1% of the world's cargo movement. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled such as drones. The Wright brothers invented and flew the first airplane in 1903, recognized as "the first sustained and controlled heavier-than-air powered flight".FAI News: 100 Years Ago, the Dream of Icarus Became Reality
posted 17 December 2003. Retrieved: 5 January 2007.
They built on the works of
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 aeri ...
dating from 1799, when he set forth the concept of the modern airplane (and later built and flew models and successful passenger-carrying
glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...
s)"Cayley, Sir George: Encyclopædia Britannica 2007"
''Encyclopædia Britannica Online'', 25 August 2007.
and the work of German pioneer of human aviation
Otto Lilienthal Karl Wilhelm Otto Lilienthal (23 May 1848 – 10 August 1896) was a German pioneer of aviation who became known as the "flying man". He was the first person to make well-documented, repeated, successful flights with gliders, therefore making ...
, who, between 1867 and 1896, also studied heavier-than-air flight. Lilienthal's flight attempts in 1891 are seen as the beginning of human flight. Following its limited use in
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, aircraft technology continued to develop. Airplanes had a presence in all the major battles of
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. The first
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, je ...
was the German
Heinkel He 178 The Heinkel He 178 was an experimental aircraft designed and produced by the German aircraft manufacturer Heinkel. It was the world's first aircraft to fly using the thrust from a turbojet engine. The He 178 was developed to test the jet propul ...
in 1939. The first
jet airliner A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly cl ...
, the
de Havilland Comet The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four d ...
, was introduced in 1952. The
Boeing 707 The Boeing 707 is an American, long-range, narrow-body airliner, the first jetliner developed and produced by Boeing Commercial Airplanes. Developed from the Boeing 367-80 prototype first flown in 1954, the initial first flew on December 20, ...
, the first widely successful commercial jet, was in commercial service for more than 50 years, from 1958 to at least 2013.


Etymology and usage

First attested in English in the late 19th century (prior to the first sustained powered flight), the word ''airplane'', like ''aeroplane'', derives from the French ''aéroplane'', which comes from the
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
ἀήρ (''aēr''), "air" and either
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''planus'', "level", or Greek πλάνος (''planos''), "wandering". "''Aéroplane''" originally referred just to the wing, as it is a
plane Plane(s) most often refers to: * Aero- or airplane, a powered, fixed-wing aircraft * Plane (geometry), a flat, 2-dimensional surface Plane or planes may also refer to: Biology * Plane (tree) or ''Platanus'', wetland native plant * Planes (gen ...
moving through the air."aeroplane
Oxford English Dictionary online.
In an example of
synecdoche Synecdoche ( ) is a type of metonymy: it is a figure of speech in which a term for a part of something is used to refer to the whole (''pars pro toto''), or vice versa (''totum pro parte''). The term comes from Greek . Examples in common Engl ...
, the word for the wing came to refer to the entire aircraft. In the United States and Canada, the term "airplane" is used for powered fixed-wing aircraft. In the United Kingdom and Ireland and most of the
Commonwealth A commonwealth is a traditional English term for a political community founded for the common good. Historically, it has been synonymous with "republic". The noun "commonwealth", meaning "public welfare, general good or advantage", dates from the ...
, the term "aeroplane" () is usually applied to these aircraft.


History


Antecedents

Many stories from antiquity involve flight, such as the
Greek legend A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
of
Icarus In Greek mythology, Icarus (; grc, Ἴκαρος, Íkaros, ) was the son of the master craftsman Daedalus, the architect of the labyrinth of Crete. After Theseus, king of Athens and enemy of Minos, escaped from the labyrinth, King Minos suspe ...
and
Daedalus In Greek mythology, Daedalus (, ; Greek: Δαίδαλος; Latin: ''Daedalus''; Etruscan: ''Taitale'') was a skillful architect and craftsman, seen as a symbol of wisdom, knowledge and power. He is the father of Icarus, the uncle of Perdix, an ...
, and the
Vimana Vimāna are mythological flying palaces or chariots described in Hindu texts and Sanskrit epics. The "Pushpaka Vimana" of Ravana (who took it from Kubera; Rama returned it to Kubera) is the most quoted example of a vimana. Vimanas are also mentio ...
in ancient
Indian epics Indian epic poetry is the epic poetry written in the Indian subcontinent, traditionally called ''Kavya'' (or ''Kāvya''; Sanskrit: काव्य, IAST: ''kāvyá''). The ''Ramayana'' and the ''Mahabharata'', which were originally composed in ...
. Around 400 BC in Greece,
Archytas Archytas (; el, Ἀρχύτας; 435/410–360/350 BC) was an Ancient Greek philosopher, mathematician, music theorist, astronomer, statesman, and strategist. He was a scientist of the Pythagorean school and famous for being the reputed founder ...
was reputed to have designed and built the first artificial, self-propelled flying device, a bird-shaped model propelled by a jet of what was probably steam, said to have flown some . This machine may have been suspended for its flight. Some of the earliest recorded attempts with gliders were those by the 9th-century Andalusian and Arabic-language poet
Abbas ibn Firnas Abu al-Qasim Abbas ibn Firnas ibn Wirdas al-Takurini ( ar, أبو القاسم عباس بن فرناس بن ورداس التاكرني; c. 809/810 – 887 A.D.), also known as Abbas ibn Firnas ( ar, عباس ابن فرناس), Latinized Armen ...
and the 11th-century English monk
Eilmer of Malmesbury Eilmer of Malmesbury (also known as Oliver due to a scribe's miscopying, or Elmer, or Æthelmær) was an 11th-century English Benedictine monk best known for his early attempt at a gliding flight using wings. Life Eilmer was a monk of Malmesb ...
; both experiments injured their pilots.
Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, Drawing, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially res ...
researched the wing design of birds and designed a man-powered aircraft in his ''
Codex on the Flight of Birds Codex on the Flight of Birds is a relatively short codex from by Leonardo da Vinci. It comprises 18 folios and measures 21 × 15 centimetres. Now held at the Royal Library of Turin, the codex begins with an examination of the flight behavior o ...
'' (1502), noting for the first time the distinction between the
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 ...
and the center of pressure of flying birds. In 1799,
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 aeri ...
set forth the concept of the modern airplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control. Cayley was building and flying models of fixed-wing aircraft as early as 1803, and he built a successful passenger-carrying
glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...
in 1853. In 1856, Frenchman
Jean-Marie Le Bris Jean Marie Le Bris (March 25, 1817, Concarneau – February 17, 1872, Douarnenez) was a French aviator, born in Concarneau, Brittany who built two glider aircraft and performed at least one flight on board of his first machine in late 1856. His ...
made the first powered flight, by having his glider ''"L'Albatros artificiel"'' pulled by a horse on a beach. Then the Russian
Alexander F. Mozhaisky Mozhaysky, identified as the "Creator of world's first airplane", on a 1963 Soviet postal stamp. Alexander Fedorovich Mozhaysky Pol. Aleksander Teodorowicz Możajski (also transliterated as Mozhayski, Mozhayskii and Mozhayskiy; russian: Алек ...
also made some innovative designs. In 1883, the American
John J. Montgomery John Joseph Montgomery (February 15, 1858 – October 31, 1911) was an American inventor, physicist, engineer, and professor at Santa Clara University in Santa Clara, California, who is best known for his invention of controlled heavier-than-air ...
made a controlled flight in a glider. Other aviators who made similar flights at that time were
Otto Lilienthal Karl Wilhelm Otto Lilienthal (23 May 1848 – 10 August 1896) was a German pioneer of aviation who became known as the "flying man". He was the first person to make well-documented, repeated, successful flights with gliders, therefore making ...
,
Percy Pilcher Percy Sinclair Pilcher (16 January 1867 – 2 October 1899) was a British inventor and pioneer aviator who was his country's foremost experimenter in unpowered flight near the end of the nineteenth century. After corresponding with Otto Lilien ...
, and
Octave Chanute Octave Chanute (February 18, 1832 – November 23, 1910) was a French-American civil engineer and aviation pioneer. He provided many budding enthusiasts, including the Wright brothers, with help and advice, and helped to publicize their flying ...
. Sir
Hiram Maxim Sir Hiram Stevens Maxim (5 February 1840 – 24 November 1916) was an American-British inventor best known as the creator of the first automatic machine gun, the Maxim gun. Maxim held patents on numerous mechanical devices such as hair-curl ...
built a craft that weighed 3.5 tons, with a wingspan that was powered by two steam engines driving two propellers. In 1894, his machine was tested with overhead rails to prevent it from rising. The test showed that it had enough lift to take off. The craft was uncontrollable and it is presumed that Maxim realized this because he subsequently abandoned work on it. In the 1890s,
Lawrence Hargrave Lawrence Hargrave, MRAeS, (29 January 18506 July 1915) was a British-born Australian engineer, explorer, astronomer, inventor and aeronautical pioneer. Biography Lawrence Hargrave was born in Greenwich, England, the second son of John Fletch ...
conducted research on wing structures and developed a
box kite A box kite is a high performance kite, noted for developing relatively high lift; it is a type within the family of cellular kites. The typical design has four parallel struts. The box is made rigid with diagonal crossed struts. There are two sa ...
that lifted the weight of a man. His box kite designs were widely adopted. Although he also developed a type of rotary aircraft engine, he did not create and fly a powered fixed-wing aircraft. Between 1867 and 1896, the German pioneer of human aviation Otto Lilienthal developed heavier-than-air flight. He was the first person to make well-documented, repeated, successful gliding flights. Lilienthal's work led to him developing the concept of the modern wing, his flight attempts in 1891 are seen as the beginning of human flight, the "
Lilienthal Normalsegelapparat The Lilienthal ''Normalsegelapparat'' (German: "Normal soaring apparatus") is a Glider aircraft, glider designed by Otto Lilienthal in Germany in the late 19th century. It is considered to be the first aeroplane to be serially produced, exampl ...
" is considered to be the first airplane in series production and his work heavily inspired the Wright brothers.


Early powered flights

The Frenchman
Clement Ader Clement or Clément may refer to: People * Clement (name), a given name and surname * Saint Clement (disambiguation)#People Places * Clément, French Guiana, a town * Clement, Missouri, U.S. * Clement Township, Michigan, U.S. Other uses * A ...
constructed his first of three flying machines in 1886, the '' Éole''. It was a bat-like design run by a lightweight
steam engine 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 a cylinder. This pushing force can be trans ...
of his own invention, with four cylinders developing , driving a four-blade
propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
. The engine weighed no more than . The wings had a span of . All-up weight was . On 9 October 1890, Ader attempted to fly the ''Éole''. Aviation historians give credit to this effort as a powered take-off and uncontrolled hop of approximately at a height of approximately . Ader's two subsequent machines were not documented to have achieved flight. The American Wright brothers flights in 1903 are recognized by the ''
Fédération Aéronautique Internationale The (; FAI; en, World Air Sports Federation) is the world governing body for air sports, and also stewards definitions regarding human spaceflight. It was founded on 14 October 1905, and is headquartered in Lausanne, Switzerland. It maintai ...
'' (FAI), the standard-setting and record-keeping body for
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 ...
, as "the first sustained and controlled heavier-than-air powered flight". By 1905, the
Wright Flyer III The Wright Flyer III was the third powered aircraft by the Wright Brothers, built during the winter of 1904–05. Orville Wright made the first flight with it on June 23, 1905. The Flyer III had an airframe of spruce construction with a wing ...
was capable of fully controllable, stable flight for substantial periods. The Wright brothers credited Otto Lilienthal as a major inspiration for their decision to pursue manned flight. In 1906, the Brazilian
Alberto Santos-Dumont Alberto Santos-Dumont (Santos Dumont, Minas Gerais, Palmira, 20 July 1873 — Guarujá, 23 July 1932) was a Brazilian aeronaut, sportsman, inventor, and one of the few people to have contributed significantly to the early development of both l ...
made what was claimed to be the first airplane flight unassisted by
catapult A catapult is a ballistic device used to launch a projectile a great distance without the aid of gunpowder or other propellants – particularly various types of ancient and medieval siege engines. A catapult uses the sudden release of stored p ...
and set the first world record recognized by the
Aéro-Club de France The Aéro-Club de France () was founded as the Aéro-Club on 20 October 1898 as a society 'to encourage aerial locomotion' by Ernest Archdeacon, Léon Serpollet, Henri de la Valette, Jules Verne and his wife, André Michelin, Albert de Dion, ...
by flying in less than 22 seconds. This flight was also certified by the FAI. An early aircraft design that brought together the modern
monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
tractor configuration In aviation, the term tractor configuration refers to an aircraft constructed in the standard configuration with its engine mounted with the propeller in front of it so that the aircraft is "pulled" through the air. Oppositely, the pusher c ...
was the
Blériot VIII The Blériot VIII was a French pioneer era aeroplane built by Louis Blériot, significant for its adoption of both a configuration and a control system that were to set a standard for decades to come. Design and development The previous year, ...
design of 1908. It had movable tail surfaces controlling both yaw and pitch, a form of roll control supplied either by wing warping or by ailerons and controlled by its pilot with a
joystick A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...
and rudder bar. It was an important predecessor of his later
Blériot XI The Blériot XI is a French aircraft of the pioneer era of aviation. The first example was used by Louis Blériot to make the first flight across the English Channel in a heavier-than-air aircraft, on 25 July 1909. This is one of the most fam ...
Channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...
-crossing aircraft of the summer of 1909.
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
served as a testbed for the use of the airplane as a weapon. Airplanes demonstrated their potential as mobile observation platforms, then proved themselves to be machines of war capable of causing casualties to the enemy. The earliest known aerial victory with a synchronized machine gun-armed
fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...
occurred in 1915, by German
Luftstreitkräfte The ''Deutsche Luftstreitkräfte'' (, German Air Force)—known before October 1916 as (Flyer Troops)—was the air arm of the Imperial German Army. In English-language sources it is usually referred to as the Imperial German Air Service, alt ...
''Leutnant''
Kurt Wintgens ''Leutnant'' Kurt Wintgens (1 August 1894 – 25 September 1916) was a German World War I fighter ace. He was the first military fighter pilot to score a victory over an opposing aircraft, while piloting an aircraft armed with a synchronized mac ...
.
Fighter aces A flying ace, fighter ace or air ace is a military aviator credited with shooting down five or more enemy aircraft during aerial combat. The exact number of aerial victories required to officially qualify as an ace is varied, but is usually co ...
appeared; the greatest (by number of Aerial Combat victories) was
Manfred von Richthofen Manfred Albrecht Freiherr von Richthofen (; 2 May 1892 – 21 April 1918), known in English as Baron von Richthofen or the Red Baron, was a fighter pilot with the German Air Force during World War I. He is considered the ace-of-aces of ...
. Following WWI, aircraft technology continued to develop.
Alcock and Brown British aviators John Alcock and Arthur Brown made the first non-stop transatlantic flight in June 1919. They flew a modified First World War Vickers Vimy bomber from St. John's, Newfoundland, to Clifden, County Galway, Ireland. The Secretary ...
crossed the Atlantic non-stop for the first time in 1919. The first international commercial flights took place between the United States and Canada in 1919. Airplanes had a presence in all the major battles of
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. They were an essential component of the military strategies of the period, such as the German
Blitzkrieg Blitzkrieg ( , ; from 'lightning' + 'war') is a word used to describe a surprise attack using a rapid, overwhelming force concentration that may consist of armored and motorized or mechanized infantry formations, together with close air su ...
, The
Battle of Britain The Battle of Britain, also known as the Air Battle for England (german: die Luftschlacht um England), was a military campaign of the Second World War, in which the Royal Air Force (RAF) and the Fleet Air Arm (FAA) of the Royal Navy defende ...
, and the American and Japanese aircraft carrier campaigns of the
Pacific War The Pacific War, sometimes called the Asia–Pacific War, was the theater of World War II that was fought in Asia, the Pacific Ocean, the Indian Ocean, and Oceania. It was geographically the largest theater of the war, including the vast ...
.


Development of jet aircraft

The first practical
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, je ...
was the German
Heinkel He 178 The Heinkel He 178 was an experimental aircraft designed and produced by the German aircraft manufacturer Heinkel. It was the world's first aircraft to fly using the thrust from a turbojet engine. The He 178 was developed to test the jet propul ...
, which was tested in 1939. In 1943, the
Messerschmitt Me 262 The Messerschmitt Me 262, nicknamed ''Schwalbe'' (German: "Swallow") in fighter versions, or ''Sturmvogel'' (German: "Storm Bird") in fighter-bomber versions, is a fighter aircraft and fighter-bomber that was designed and produced by the Germa ...
, the first operational jet fighter aircraft, went into service in the German
Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...
. The first
jet airliner A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly cl ...
, the
de Havilland Comet The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four d ...
, was introduced in 1952. The
Boeing 707 The Boeing 707 is an American, long-range, narrow-body airliner, the first jetliner developed and produced by Boeing Commercial Airplanes. Developed from the Boeing 367-80 prototype first flown in 1954, the initial first flew on December 20, ...
, the first widely successful commercial jet, was in commercial service for more than 50 years, from 1958 to 2010. The
Boeing 747 The Boeing 747 is a large, long-range wide-body airliner designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2022. After introducing the 707 in October 1958, Pan Am wanted a jet times its size, t ...
was the world's biggest passenger aircraft from 1970 until it was surpassed by the
Airbus A380 The Airbus A380 is a large wide-body airliner that was developed and produced by Airbus. It is the world's largest passenger airliner and only full-length double-deck jet airliner. Airbus studies started in 1988, and the project was annou ...
in 2005. Supersonic airliner flights, including those of the
Concorde The Aérospatiale/BAC Concorde () is a retired Franco-British supersonic airliner jointly developed and manufactured by Sud Aviation (later Aérospatiale) and the British Aircraft Corporation (BAC). Studies started in 1954, and France an ...
, have been limited to over-water flight at supersonic speed because of their
sonic boom A sonic boom is a sound associated with shock waves created when an object travels through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding similar to an explosion or a thunderclap to t ...
, which is prohibited over most populated land areas. The high cost of operation per passenger-mile and a deadly crash in 2000 induced the operators of the Concorde to remove it from service.


Propulsion


Propeller

An
aircraft propeller An aircraft propeller, also called an airscrew,Beaumont, R.A.; ''Aeronautical Engineering'', Odhams, 1942, Chapter 13, "Airscrews". converts rotary motion from an engine or other power source into a swirling slipstream which pushes the propeller ...
, or ''airscrew'', converts rotary motion from an
engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...
or other power source, into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached two or more radial
airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
-section blades such that the whole assembly rotates about a longitudinal axis.Beaumont, R.A.; ''Aeronautical Engineering'', Odhams, 1942, Chapter 13, "Airscrews". Three types of aviation engines used to power propellers include
reciprocating engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...
s (or piston engines),
gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
s, and
electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s. The amount of thrust a propeller creates is determined, in part, by its disk area—the area through which the blades rotate. The limitation on blade speed is the
speed of sound The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At , the speed of sound in air is about , or one kilometre in or one mile in . It depends strongly on temperature as w ...
; as when the blade tip exceeds the speed of sound, shock waves decrease propeller efficiency. The rpm required to generate a given tip speed is inversely proportional to the diameter of the propeller. The upper design speed limit for propeller-driven aircraft is Mach 0.6. Aircraft designed to go faster than that employ jet engines.


Reciprocating engine

Reciprocating engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...
s in aircraft have three main variants,
radial Radial is a geometric term of location which may refer to: Mathematics and Direction * Vector (geometric) In mathematics, physics, and engineering, a Euclidean vector or simply a vector (sometimes called a geometric vector or spatial vector) ...
, in-line and flat or horizontally opposed engine. The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel and was commonly used for aircraft engines before gas turbine engines became predominant. An inline engine is a reciprocating engine with banks of cylinders, one behind another, rather than rows of cylinders, with each bank having any number of cylinders, but rarely more than six, and may be water-cooled. A flat engine is an internal combustion engine with horizontally-opposed cylinders.


Gas turbine

A turboprop gas turbine engine consists of an intake, compressor, combustor, turbine, and a propelling nozzle, which provide power from a shaft through a reduction gearing to the propeller. The propelling nozzle provides a relatively small proportion of the thrust generated by a turboprop.


Electric motor

An
electric aircraft An electric aircraft is an aircraft powered by electricity. Electric aircraft are seen as a way to reduce the environmental effects of aviation, providing zero emissions and quieter flights. Electricity may be supplied by a variety of methods, ...
runs on
electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s with electricity coming from
fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
s,
solar cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.
s,
ultracapacitors A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than other capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and Rechargeable ba ...
,
power beaming Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, ...
, or
batteries Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...
. Currently, flying electric aircraft are mostly experimental prototypes, including manned and
unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
s, but there are some production models on the market.


Jet

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, je ...
are propelled by
jet engine A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term ...
s, which are used because the aerodynamic limitations of propellers do not apply to jet propulsion. These engines are much more powerful than a reciprocating engine for a given size or weight and are comparatively quiet and work well at higher altitude. Variants of the jet engine include the
ramjet A ramjet, or athodyd (aero thermodynamic duct), is a form of airbreathing jet engine that uses the forward motion of the engine to produce thrust. Since it produces no thrust when stationary (no ram air) ramjet-powered vehicles require an ass ...
and the
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 ...
, which rely on high airspeed and intake geometry to compress the combustion air, prior to the introduction and ignition of fuel. Rocket motors provide thrust by burning a fuel with an oxidizer and expelling gas through a nozzle.


Turbofan

Most jet aircraft use
turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...
jet engines, which employ a
gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
to drive a ducted fan, which accelerates air ''around'' the turbine to provide thrust in addition to that which is accelerated ''through'' the turbine. The ratio of air passing around the turbine to that passing through is called the by-pass ratio. They represent a compromise between
turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...
(with no bypass) and
turboprop A turboprop 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 enters the intake and is compressed by the compressor. Fuel ...
forms of aircraft propulsion (primarily powered with bypass air). Subsonic aircraft, such as airliners, employ high by-pass jet engines for fuel efficiency.
Supersonic aircraft A supersonic aircraft is an aircraft capable of supersonic flight, that is, flying faster than the speed of sound (Mach number 1). Supersonic speed, Supersonic aircraft were developed in the second half of the twentieth century. Supersonic airc ...
, such as jet fighters, use low-bypass turbofans. However at supersonic speeds, the air entering the engine must be decelerated to a subsonic speed and then re-accelerated back to supersonic speeds after combustion. An
afterburner An afterburner (or reheat in British English) 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 comba ...
may be used on combat aircraft to increase power for short periods of time by injecting fuel directly into the hot exhaust gases. Many jet aircraft also use
thrust reverser Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft ...
s to slow down after landing.


Ramjet

A ramjet is a form of jet engine that contains no major moving parts and can be particularly useful in applications requiring a small and simple engine for high-speed use, such as with missiles. Ramjets require forward motion before they can generate thrust and so are often used in conjunction with other forms of propulsion, or with an external means of achieving sufficient speed. The
Lockheed D-21 The Lockheed D-21 is an American supersonic reconnaissance drone. The D-21 was initially designed to be launched from the back of an M-21 carrier aircraft, a variant of the Lockheed A-12 aircraft. The drone had maximum speed in excess of at a ...
was a Mach 3+ ramjet-powered reconnaissance drone that was launched from a
parent aircraft An airborne aircraft carrier is a type of mother ship aircraft which can carry, launch, retrieve and support other smaller parasite aircraft. The only dedicated examples to have been built were airships, although existing heavier-than-air airc ...
. A ramjet uses the vehicle's forward motion to force air through the engine without resorting to turbines or vanes. Fuel is added and ignited, which heats and expands the air to provide thrust.


Scramjet

A scramjet is a specialized ramjet that uses internal supersonic airflow to compress, combine with fuel, combust and accelerate the exhaust to provide thrust. The engine operates at supersonic speeds only. 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 severa ...
, an experimental unmanned scramjet, set a world speed record in 2004 for a jet-powered aircraft with a speed of Mach 9.7, nearly .


Rocket

Whereas jet aircraft use the atmosphere both as a source of
oxidant An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxid ...
and of mass to accelerate reactively behind the aircraft, rocket aircraft carry the oxidizer on board and accelerate the burned fuel and oxidizer backwards as the sole source of mass for reaction. Liquid fuel and oxidizer may be pumped into a combustion chamber or a solid fuel with oxidizer may burn in the fuel chamber. Whether liquid or solid-fueled, the hot gas is accelerated through a nozzle. In
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, the Germans deployed the Me 163 Komet
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 typicall ...
. The first plane to break the
sound barrier The sound barrier or sonic barrier is the large increase in aerodynamic drag and other undesirable effects experienced by an aircraft or other object when it approaches the speed of sound. When aircraft first approached the speed of sound, th ...
in level flight was a rocket plane – the
Bell X-1 The Bell X-1 (Bell Model 44) is a rocket engine–powered aircraft, designated originally as the XS-1, and was a joint National Advisory Committee for Aeronautics– U.S. Army Air Forces–U.S. Air Force supersonic research project built by Be ...
in 1948. 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 an ...
broke many speed and
altitude records Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...
in the 1960s and pioneered engineering concepts for later aircraft and spacecraft. Military transport aircraft may employ
rocket-assisted take off JATO (acronym for jet-assisted take-off) is a type of assisted take-off for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets. The term ''JATO'' is used interchangeably with the (more specific ...
s for short-field situations. Otherwise, rocket aircraft include
spaceplane A spaceplane is a vehicle that can fly and glide like an aircraft in Earth's atmosphere and maneuver like a spacecraft in outer space. To do so, spaceplanes must incorporate features of both aircraft and spacecraft. Orbital spaceplanes ten ...
s, like
SpaceShipTwo The Scaled Composites Model 339 SpaceShipTwo (SS2) is an air-launched suborbital spaceplane type designed for space tourism. It is manufactured by The Spaceship Company, a California-based company owned by Virgin Galactic. SpaceShipTwo is car ...
, for travel beyond the Earth's atmosphere and sport aircraft developed for the short-lived
Rocket Racing League The Rocket Racing League was a racing league that planned to use rocket-powered aircraft to race a closed-circuit air racetrack. Founded in 2005, the league made its first public flights in 2010 and was working to begin regular racing seasons. ...
.


Design and manufacture

Most airplanes are constructed by companies with the objective of producing them in quantity for customers. The design and planning process, including safety tests, can last up to four years for small turboprops or longer for larger planes. During this process, the objectives and design specifications of the aircraft are established. First the construction company uses drawings and equations, simulations, wind tunnel tests and experience to predict the behavior of the aircraft. Computers are used by companies to draw, plan and do initial simulations of the aircraft. Small models and mockups of all or certain parts of the plane are then tested in wind tunnels to verify its aerodynamics. When the design has passed through these processes, the company constructs a limited number of prototypes for testing on the ground. Representatives from an aviation governing agency often make a first flight. The flight tests continue until the aircraft has fulfilled all the requirements. Then, the governing public agency of aviation of the country authorizes the company to begin production. In the United States, this agency is the
Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
(FAA). In the European Union,
European Aviation Safety Agency The European Union Aviation Safety Agency (EASA) is an agency of the European Union (EU) with responsibility for civil aviation safety. It carries out certification, regulation and standardisation and also performs investigation and monitorin ...
(EASA); in the United Kingdom it is the
Civil Aviation Authority A civil aviation authority (CAA) is a national or supranational statutory authority that oversees the regulation of civil aviation, including the maintenance of an aircraft register. Role Due to the inherent dangers in the use of flight vehicles, ...
(CAA). In Canada, the public agency in charge and authorizing the mass production of aircraft is Transport Canada's Civil Aviation Authority. When a part or component needs to be joined together by welding for virtually any aerospace or defense application, it must meet the most stringent and specific safety regulations and standards.
Nadcap Nadcap (formerly NADCAP, the National Aerospace and Defense Contractors Accreditation Program) is a global cooperative accreditation program for aerospace engineering, defense contractor, defense and related industries. History of Nadcap The Nadc ...
, or the National Aerospace and Defense Contractors Accreditation Program sets global requirements for quality, quality management and quality assurance for aerospace engineering. In the case of international sales, a license from the public agency of aviation or transport of the country where the aircraft is to be used is also necessary. For example, airplanes made by the European company,
Airbus Airbus SE (; ; ; ) is a European Multinational corporation, multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace manufacturer, aerospace products worldwide and manufactures aircraft througho ...
, need to be certified by the FAA to be flown in the United States, and airplanes made by U.S.-based
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...
need to be approved by the EASA to be flown in the European Union. Regulations have resulted in reduced
noise Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...
from aircraft engines in response to increased
noise pollution Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is main ...
from growth in air traffic over urban areas near airports. Small planes can be designed and constructed by amateurs as homebuilts. Other
homebuilt aircraft Homebuilt aircraft, also known as amateur-built aircraft or kit planes, 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.Armstrong, Kenn ...
can be assembled using pre-manufactured kits of parts that can be assembled into a basic plane and must then be completed by the builder.Purdy, Don: ''AeroCrafter - Homebuilt Aircraft Sourcebook, Fifth Edition'', pages 1-164. BAI Communications, 15 July 1998. Few companies produce planes on a large scale. However, the production of a plane for one company is a process that actually involves dozens, or even hundreds, of other companies and plants, that produce the parts that go into the plane. For example, one company can be responsible for the production of the landing gear, while another one is responsible for the radar. The production of such parts is not limited to the same city or country; in the case of large plane manufacturing companies, such parts can come from all over the world. The parts are sent to the main plant of the plane company, where the production line is located. In the case of large planes, production lines dedicated to the assembly of certain parts of the plane can exist, especially the wings and the fuselage. When complete, a plane is rigorously inspected to search for imperfections and defects. After approval by inspectors, the plane is put through a series of
flight test Flight testing is a branch of aeronautical engineering that develops specialist equipment required for testing aircraft behaviour and systems. Instrumentation systems are developed using proprietary transducers and data acquisition systems. D ...
s to assure that all systems are working correctly and that the plane handles properly. Upon passing these tests, the plane is ready to receive the "final touchups" (internal configuration, painting, etc.), and is then ready for the customer.


Characteristics


Airframe

The structural parts of a fixed-wing aircraft are called the airframe. The parts present can vary according to the aircraft's type and purpose. Early types were usually made of wood with fabric wing surfaces, When engines became available for powered flight around a hundred years ago, their mounts were made of metal. Then as speeds increased more and more parts became metal until by the end of WWII all-metal aircraft were common. In modern times, increasing use of
composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
s has been made. Typical structural parts include: * One or more large horizontal ''wings'', often with an
airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
cross-section shape. The wing deflects air downward as the aircraft moves forward, generating
lifting force A fluid flowing around 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 flow directi ...
to support it in flight. The wing also provides stability in
roll Roll or Rolls may refer to: Movement about the longitudinal axis * Roll angle (or roll rotation), one of the 3 angular degrees of freedom of any stiff body (for example a vehicle), describing motion about the longitudinal axis ** Roll (aviation), ...
to stop the aircraft from rolling to the left or right in steady flight. * A ''
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
'', a long, thin body, usually with tapered or rounded ends to make its shape
aerodynamically Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
smooth. The fuselage joins the other parts of the airframe and usually contains important things such as the pilot, payload and flight systems. * A ''
vertical stabilizer A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...
'' or fin is a vertical wing-like surface mounted at the rear of the plane and typically protruding above it. The fin stabilizes the plane's yaw (turn left or right) and mounts the
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...
, which controls its rotation along that axis. * A ''
horizontal stabilizer A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplan ...
'' or
tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplane ...
, usually mounted at the tail near the vertical stabilizer. The horizontal stabilizer is used to stabilize the plane's pitch (tilt up or down) and mounts the
elevators An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They are ...
, which provide pitch control. * ''
Landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...
'', a set of wheels, skids, or floats that support the plane while it is on the surface. On seaplanes, the bottom of the fuselage or floats (pontoons) support it while on the water. On some planes the landing gear retracts during flight to reduce drag.


Wings

The wings of a fixed-wing aircraft are static planes extending either side of the aircraft. When the aircraft travels forwards, air flows over the wings, which are shaped to create lift. This shape is called an
airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
and is shaped like a bird's wing.


Wing structure

Airplanes have flexible wing surfaces which are stretched across a frame and made rigid by the lift forces exerted by the airflow over them. Larger aircraft have rigid wing surfaces which provide additional strength. Whether flexible or rigid, most wings have a strong frame to give them their shape and to transfer lift from the wing surface to the rest of the aircraft. The main structural elements are one or more spars running from root to tip, and many ribs running from the leading (front) to the trailing (rear) edge. Early airplane engines had little power, and lightness was very important. Also, early airfoil sections were very thin, and could not have a strong frame installed within. So, until the 1930s, most wings were too lightweight to have enough strength, and external bracing struts and wires were added. When the available engine power increased during the 1920s and 30s, wings could be made heavy and strong enough that bracing was not needed any more. This type of unbraced wing is called a cantilever wing.


Wing configuration

The number and shape of the wings varies widely on different types. A given wing plane may be full-span or divided by a central
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
into port (left) and starboard (right) wings. Occasionally, even more wings have been used, with the three-winged
triplane A triplane is a fixed-wing aircraft equipped with three vertically stacked wing planes. Tailplanes and canard foreplanes are not normally included in this count, although they occasionally are. Design principles The triplane arrangement may ...
achieving some fame in WWI. The four-winged
quadruplane In aviation, a multiplane is a fixed-wing aircraft-configuration featuring multiple wing planes. The wing planes may be stacked one above another, or one behind another, or both in combination. Types having a small number of planes have specific nam ...
and other
multiplane The multiplane camera is a motion-picture camera that was used in the traditional animation process that moves a number of pieces of artwork past the camera at various speeds and at various distances from one another. This creates a sense of par ...
designs have had little success. A
monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
has a single wing plane, a
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 ...
has two stacked one above the other, a
tandem wing QAC Quickie Q2 A tandem wing is a wing configuration in which a flying craft or animal has two or more sets of wings set one behind another. All the wings contribute to lift. The tandem wing is distinct from the biplane in which the wings are s ...
has two placed one behind the other. When the available engine power increased during the 1920s and 30s and bracing was no longer needed, the unbraced or cantilever monoplane became the most common form of powered type. The wing
planform In technical drawing and computer graphics, a multiview projection is a technique of illustration by which a standardized series of orthographic two-dimensional pictures are constructed to represent the form of a three-dimensional object. Up to ...
is the shape when seen from above. To be aerodynamically efficient, a wing should be straight with a long span from side to side but have a short chord (high aspect ratio). But to be structurally efficient, and hence light weight, a wing must have a short span but still enough area to provide lift (low aspect ratio). At transonic speeds (near the speed of sound), it helps to sweep the wing backwards or forwards to reduce drag from supersonic shock waves as they begin to form. The
swept wing A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction. Swept wings have been flown since the pioneer days of aviation. Wing sweep at high speeds was first investigate ...
is just a straight wing swept backwards or forwards. The
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 suitabl ...
is a triangle shape that may be used for several reasons. As a flexible
Rogallo wing The Rogallo wing is a flexible type of wing. In 1948, Francis Rogallo, a NASA engineer, and his wife Gertrude Rogallo, invented a self-inflating flexible wing they called the Parawing, also known after them as the "Rogallo Wing" and flexible wing ...
, it allows a stable shape under aerodynamic forces and so is often used for ultralight aircraft and even
kites A kite is a tethered heavier than air flight, heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create Lift (force), lift and Drag (physics), drag forces. A kite consists of wings, tethers and anchors. ...
. As a supersonic wing, it combines high strength with low drag and so is often used for fast jets. A variable geometry wing can be changed in flight to a different shape. The
variable-sweep wing A variable-sweep wing, colloquially known as a "swing wing", is an airplane wing, or set of wings, that may be swept back and then returned to its original straight position during flight. It allows the aircraft's shape to be modified in fli ...
transforms between an efficient straight configuration for takeoff and landing, to a low-drag swept configuration for high-speed flight. Other forms of variable planform have been flown, but none have gone beyond the research stage.


Fuselage

A ''
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
'' is a long, thin body, usually with tapered or rounded ends to make its shape
aerodynamically Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
smooth. The fuselage may contain the
flight crew Aircrew, also called flight crew, are personnel who operate an aircraft while in flight. The composition of a flight's crew depends on the type of aircraft, plus the flight's duration and purpose. Commercial aviation Flight deck positions ...
, passengers, cargo or
payload Payload is the object or the entity which is being carried by an aircraft or launch vehicle. Sometimes payload also refers to the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight. Depending on the nature of ...
, fuel and engines. The pilots of manned aircraft operate them from a ''
cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...
'' located at the front or top of the fuselage and equipped with controls and usually windows and instruments. A plane may have more than one fuselage, or it may be fitted with booms with the tail located between the booms to allow the extreme rear of the fuselage to be useful for a variety of purposes.


Wings vs. bodies


Flying wing

A flying wing is a
tailless aircraft In aeronautics, a tailless aircraft is an aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin (vertical stabilizer), and/or vertical rudder. Theoretical advantages of the ...
which has no definite
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
. Most of the crew, payload and equipment are housed inside the main wing structure.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 224. Aviation Supplies & Academics, 1997. The flying wing configuration was studied extensively in the 1930s and 1940s, notably by
Jack Northrop John Knudsen Northrop (November 10, 1895 – February 18, 1981) was an American aircraft industrialist and designer who founded the Northrop Corporation in 1939. His career began in 1916 as a draftsman for Loughead Aircraft Manufacturing Com ...
and
Cheston L. Eshelman Eshelman was a marque of small American automobiles (1953–1961) and other vehicles and implements including motor scooters, garden tractors, pleasure boats, aircraft, golf carts, snowplows, trailers, mail-delivery vehicles and more. The ...
in the United States, and
Alexander Lippisch Alexander Martin Lippisch (November 2, 1894 – February 11, 1976) was a German aeronautical engineer, a pioneer of aerodynamics who made important contributions to the understanding of tailless aircraft, delta wings and the ground effect, and a ...
and the
Horten brothers Walter Horten (born 13 November 1913 in Bonn; died 9 December 1998 in Baden-Baden, Germany) and Reimar Horten (born 12 March 1915 in Bonn; died 14 March 1994 in Villa General Belgrano, Argentina), sometimes credited as the Horten Brothers, were ...
in Germany. After the war, several experimental designs were based on the flying wing concept, but the known difficulties remained intractable. Some general interest continued until the early 1950s but designs did not necessarily offer a great advantage in range and presented several technical problems, leading to the adoption of "conventional" solutions like the
Convair B-36 The Convair B-36 "Peacemaker" is a strategic bomber that was built by Convair and operated by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built. It had the longest win ...
and the
B-52 Stratofortress The Boeing B-52 Stratofortress is an American long-range, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the United States Air ...
. Due to the practical need for a deep wing, the flying wing concept is most practical for designs in the slow-to-medium speed range, and there has been continual interest in using it as a tactical
airlift An airlift is the organized delivery of supplies or personnel primarily via military transport aircraft. Airlifting consists of two distinct types: strategic and tactical. Typically, strategic airlifting involves moving material long distanc ...
er design. Interest in flying wings was renewed in the 1980s due to their potentially low
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
reflection cross-sections.
Stealth technology Stealth technology, also termed low observable technology (LO technology), is a sub-discipline of military tactics and passive and active electronic countermeasures, which covers a range of methods used to make personnel, aircraft, ships, subm ...
relies on shapes which only reflect radar waves in certain directions, thus making the aircraft hard to detect unless the radar receiver is at a specific position relative to the aircraft - a position that changes continuously as the aircraft moves. This approach eventually led to the Northrop
B-2 Spirit The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying ...
stealth bomber. In this case, the aerodynamic advantages of the flying wing are not the primary needs. However, modern computer-controlled
fly-by-wire Fly-by-wire (FBW) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires, and flight control co ...
systems allowed for many of the aerodynamic drawbacks of the flying wing to be minimized, making for an efficient and stable long-range bomber.


Blended wing body

Blended wing body aircraft have a flattened and airfoil shaped body, which produces most of the lift to keep itself aloft, and distinct and separate wing structures, though the wings are smoothly blended in with the body. Thus blended wing bodied aircraft incorporate design features from both a futuristic fuselage and flying wing design. The purported advantages of the blended wing body approach are efficient high-lift wings and a wide
airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
-shaped body. This enables the entire craft to contribute to
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...
generation with the result of potentially increased fuel economy.


Lifting body

A lifting body is a configuration in which the body itself produces
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...
. In contrast to a
flying wing A flying wing is a tailless fixed-wing aircraft that has no definite fuselage, with its crew, payload, fuel, and equipment housed inside the main wing structure. A flying wing may have various small protuberances such as pods, nacelles, blis ...
, which is a wing with minimal or no conventional
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
, a lifting body can be thought of as a fuselage with little or no conventional wing. Whereas a flying wing seeks to maximize cruise efficiency at
subsonic Subsonic may refer to: Motion through a medium * Any speed lower than the speed of sound within a sound-propagating medium * Subsonic aircraft, a flying machine that flies at air speeds lower than the speed of sound * Subsonic ammunition, a type o ...
speeds by eliminating non-lifting surfaces, lifting bodies generally minimize the drag and structure of a wing for subsonic,
supersonic Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
, and
hypersonic In aerodynamics, a hypersonic speed is one that exceeds 5 times 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 flying at hypersonic speed varies, since in ...
flight, or,
spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...
re-entry Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the entr ...
. All of these flight regimes pose challenges for proper flight stability. Lifting bodies were a major area of research in the 1960s and 70s as a means to build a small and lightweight manned spacecraft. The US built several famous lifting body rocket planes to test the concept, as well as several rocket-launched re-entry vehicles that were tested over the Pacific. Interest waned as the
US Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
lost interest in the manned mission, and major development ended during the
Space Shuttle design process Before the Apollo 11 Moon landing in 1969, NASA began studies of Space Shuttle designs as early as October 1968. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific. The primary intended u ...
when it became clear that the highly shaped fuselages made it difficult to fit fuel tankage.


Empennage and foreplane

The classic
airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...
section wing is unstable in flight and difficult to control. Flexible-wing types often rely on an anchor line or the weight of a pilot hanging beneath to maintain the correct attitude. Some free-flying types use an adapted airfoil that is stable, or other ingenious mechanisms including, most recently, electronic artificial stability. To achieve stability and control, most fixed-wing types have an
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 ed ...
comprising a fin and rudder which act horizontally and a tailplane and elevator which act vertically. These control surfaces can typically be trimmed to relieve control forces for various stages of flight. This is so common that it is known as the conventional layout. Sometimes there may be two or more fins, spaced out along the tailplane. Some types have a horizontal " canard" foreplane ahead of the main wing, instead of behind it.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 86. Aviation Supplies & Academics, 1997. Aviation Publishers Co. Limited, ''From the Ground Up'', page 10 (27th revised edition) This foreplane may contribute to the lift, the trim, or control of the aircraft, or to several of these.


Controls and instruments

Airplanes have complex
flight control system A conventional Fixed-wing aircraft, 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 ...
s. The main controls allow the pilot to direct the aircraft in the air by controlling the
attitude Attitude may refer to: Philosophy and psychology * Attitude (psychology), an individual's predisposed state of mind regarding a value * Metaphysics of presence * Propositional attitude, a relational mental state connecting a person to a pro ...
(roll, pitch and yaw) and engine thrust. On manned aircraft,
cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...
instruments provide information to the pilots, including flight data, engine output, navigation, communications and other aircraft systems that may be installed.


Safety

When risk is measured by deaths per passenger kilometer, air travel is approximately 10 times safer than travel by bus or rail. However, when using the deaths per journey statistic, air travel is significantly more dangerous than car, rail, or bus travel. Air travel insurance is relatively expensive for this reason—insurers generally use the deaths per journey statistic. There is a significant difference between the safety of airliners and that of smaller private planes, with the per-mile statistic indicating that airliners are 8.3 times safer than smaller planes.


Environmental impact

Like all activities involving
combustion 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. Combusti ...
, fossil-fuel-powered aircraft release
soot Soot ( ) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed ...
and other pollutants into the atmosphere.
Greenhouse gas A greenhouse gas (GHG or GhG) is a gas that Absorption (electromagnetic radiation), absorbs and Emission (electromagnetic radiation), emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse ...
es such as
carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
(CO2) are also produced. In addition, there are environmental impacts specific to airplanes: for instance, * Airplanes operating at high altitudes near the
tropopause The tropopause is the atmospheric boundary that demarcates the troposphere from the stratosphere; which are two of the five layers of the atmosphere of Earth. The tropopause is a thermodynamic gradient-stratification layer, that marks the end of ...
(mainly large
jet airliner A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly cl ...
s) emit aerosols and leave
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 ar ...
s, both of which can increase
cirrus cloud Cirrus ( cloud classification symbol: Ci) is a genus of high cloud made of ice crystals. Cirrus clouds typically appear delicate and wispy with white strands. Cirrus are usually formed when warm, dry air rises, causing water vapor deposition on ...
formationcloud cover may have increased by up to 0.2% since the birth of aviation. * Airplanes operating at high altitudes near the tropopause can also release chemicals that interact with greenhouse gases at those altitudes, particularly
nitrogen compounds The chemical element nitrogen is one of the most abundant elements in the universe and can form many compounds. It can take several oxidation states; but the most oxidation states are -3 and +3. Nitrogen can form nitride and nitrate ions. It also fo ...
, which interact with ozone, increasing ozone concentrations. * Most light piston aircraft burn
avgas Avgas (aviation gasoline, also known as aviation spirit in the UK) is an aviation fuel used in aircraft with spark-ignited internal combustion engines. ''Avgas'' is distinguished from conventional gasoline (petrol) used in motor vehicles, w ...
, which contains
tetraethyllead Tetraethyllead (commonly styled tetraethyl lead), abbreviated TEL, is an organolead compound with the formula Pb( C2H5)4. It is a fuel additive, first being mixed with gasoline beginning in the 1920s as a patented octane rating booster that al ...
(TEL). Some lower-compression piston engines can operate on unleaded mogas and turbine engines and diesel enginesneither of which require leadare used on some newer
light aircraft A light aircraft is an aircraft that has a maximum gross takeoff weight of or less.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 308. Aviation Supplies & Academics, 1997. Light aircraft are used as utility aircraft c ...
. Some non-polluting light
electric aircraft An electric aircraft is an aircraft powered by electricity. Electric aircraft are seen as a way to reduce the environmental effects of aviation, providing zero emissions and quieter flights. Electricity may be supplied by a variety of methods, ...
are already in production. Another environmental impact of airplanes is
noise pollution Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is main ...
, mainly caused by aircraft taking off and landing.


See also

*
Aircraft flight mechanics Aircraft flight mechanics are relevant to fixed wing ( gliders, aeroplanes) and rotary wing (helicopters) aircraft. An aeroplane (''airplane'' in US usage), is defined in ICAO Document 9110 as, "a power-driven heavier than air aircraft, deriving i ...
*
Aviation Aviation includes 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 ...
*
Fuel efficiency Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, wh ...
*
List of altitude records reached by different aircraft types This listing of flight altitude records are the records set for the highest aeronautical flights conducted in the atmosphere, set since the age of ballooning. Some, but not all of the records were certified by the non-profit international avia ...
*
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 Internati ...


References


Bibliography

* Blatner, David. ''The Flying Book: Everything You've Ever Wondered About Flying On Airplanes''.


External links


The Aeroplane centre

Airliners.net

Aerospaceweb.org


{{DEFAULTSORT:Airplane Aircraft categories Aircraft configurations American inventions Vehicles introduced in 1903