Airplane

An airplane (American English), or aeroplane (Commonwealth English), also plane, is a fixed-wing aircraft that is pushed forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in many sizes and shapes. They are used for recreation, transportation of goods and people, military purposes, and research.

All around the world, commercial aviation carries more than four billion passengers each year on airliners. Most airplanes have a pilot on board, but some are remotely or computer-controlled, such as drones.

The Wright brothers invented and flew the first airplane in 1903. Their flight was recognized as "the first sustained and controlled heavier-than-air powered flight." They built on the work of George Cayley, who described the idea of the modern airplane in 1799 and later built and flew models and gliders that could carry people. They also built on the work of German pioneer of human aviation Otto Lilienthal, who studied flight between 1867 and 1896. Lilienthal's flight attempts in 1891 are seen as the beginning of human flight.

After World War I, aircraft technology kept growing. Airplanes were part of all the major battles of World War II. The first jet aircraft was the German Heinkel He 178 in 1939, and the first jet airliner, the de Havilland Comet, began flying in 1952. The Boeing 707, the first widely successful commercial jet, was used for passenger flights from 1958 to 2019.

This article is about the aircraft. For the comedy film, see Airplane!. For other uses, see Airplane (disambiguation). "Aeroplane" redirects here. For other uses, see Aeroplane (disambiguation).

Etymology and usage

The word airplane was first used in English in the late 1800s, before the first powered flight. Like aeroplane, it comes from the French word aéroplane. That word combines the Greek word for "air" with either the Latin word for "level" or a Greek word meaning "wandering." At first, aéroplane referred only to the wing, which is a plane moving through the air. Through synecdoche, a way of using a part to mean the whole, the word for the wing came to mean the whole aircraft.

In the United States and Canada, "airplane" is used for powered aircraft with fixed wings. In the United Kingdom, Ireland, and most of the Commonwealth, people usually say "aeroplane." According to the Oxford English Dictionary, "airplane" became the standard U.S. term after the National Advisory Committee for Aeronautics started using it in 1916.

History

Main articles: Aviation history and First flying machine

People have told stories about flying for a very long time. One is the Greek legend of Icarus and Daedalus. Another is the Vimana in ancient Indian epics. Around 400 BC in Greece, Archytas was said to have built a bird-shaped flying model. It was pushed forward by a jet of what was probably steam. Early gliders were tried by Abbas ibn Firnas and Eilmer of Malmesbury. Leonardo da Vinci studied bird wings. In his Codex on the Flight of Birds (1502), he designed a flying machine that a person would power. In 1799, George Cayley described the modern airplane. He imagined a fixed-wing machine with separate parts for lift, propulsion, and control. In 1856, Frenchman Jean-Marie Le Bris made the first powered flight. His glider was pulled by a horse along a beach. The Russian Alexander F. Mozhaisky also created new designs. In 1883, the American John J. Montgomery made a controlled glider flight. Otto Lilienthal, Percy Pilcher, and Octave Chanute made similar flights. Lilienthal's work greatly inspired the Wright brothers. His "Lilienthal Normalsegelapparat" is considered the first airplane made in series. Lawrence Hargrave built a box kite that could lift the weight of a man. In 1886, the Frenchman Clement Ader built his first flying machine, the Éole. It had a steam engine of 20 horsepower (15 kW) and a propeller. On 9 October 1890, he tried to fly it. Historians say this was a powered hop of about 50 m (160 ft).

In 1903, the American Wright brothers made flights that are recognized today. The Fédération Aéronautique Internationale (FAI) is the group that sets standards and keeps records for aeronautics. It calls their flight "the first sustained and controlled heavier-than-air powered flight." By 1905, the Wright Flyer III could fly in a controlled and steady way for long periods. In 1906, the Brazilian Alberto Santos-Dumont made what was claimed to be the first airplane flight without a catapult. His flight set a record recognized by the Aéro-Club de France. The Blériot VIII design of 1908 combined the modern monoplane and tractor configuration. It was an important step toward the Blériot XI, which flew across the Channel in 1909. During World War I, people learned that airplanes could be used to watch enemy movements and as war machines. In 1915, German Luftstreitkräfte Leutnant Kurt Wintgens flew the earliest known fighter aircraft with a synchronized machine gun. Fighter aces appeared. The one with the most aerial victories was Manfred von Richthofen, also known as the Red Baron. In 1919, Alcock and Brown crossed the Atlantic without stopping for the first time. Airplanes played a part in all the major battles of World War II. These included the German Blitzkrieg, the Battle of Britain, and the aircraft carrier campaigns of the Pacific War. The first practical jet aircraft, the German Heinkel He 178, was tested in 1939. The Messerschmitt Me 262 entered service in the German Luftwaffe in 1943. The first jet airliner, the de Havilland Comet, arrived in 1952. It was followed by the Boeing 707 and the Boeing 747. The Boeing 747 was the world's biggest passenger airplane until the Airbus A380 in 2005. Supersonic airliner flights, including those of the Concorde, have been limited to flying over water because of their sonic boom. A crash in 2000 and high operating costs led the Concorde's operators to stop flying it.

Propulsion

See also: Powered aircraft and Aircraft engine

Main articles: Propeller (aeronautics) and Aircraft engine

A propeller, also called an airscrew, turns the power from an engine into moving air. This air pushes the aircraft forward or backward. A propeller has a central hub with two or more blades that spin together. Propellers can be powered by reciprocating engines (piston engines), gas turbines, or electric motors. How much push a propeller makes depends partly on how much space its blades cover as they spin. Blades that move faster than the speed of sound do not work as well. Propeller planes are built to fly up to Mach 0.6. Faster planes use jet engines. Piston engines in aircraft come in three main types: radial, in-line, and flat or horizontally opposed. Gas turbine engines that turn propellers are called turboprops. Electric aircraft use electric motors powered by fuel cells, solar cells, ultracapacitors, power beaming, or batteries. Most electric aircraft are still being tested. However, some unmanned aerial vehicles and a few models are already for sale.

Main article: Jet engine

Jet aircraft are powered by jet engines. Jet engines are stronger than piston engines of the same size or weight. They are also quieter and work well at high altitude. Most jet aircraft use turbofan engines. These engines push air both through and around the engine's turbine. The ratio between these two airflows is called the by-pass ratio. Airliners use engines with a high by-pass ratio to save fuel. Supersonic aircraft, such as jet fighters, use turbofans with a low by-pass ratio. Combat aircraft may use an afterburner to add power for short periods. Many jets use thrust reversers to slow down after landing. A ramjet has no major moving parts. It needs to be moving forward before it can make thrust. The Lockheed D-21, a Mach 3+ reconnaissance drone, worked this way. It was launched from a parent aircraft. A scramjet is a special kind of ramjet that works only at supersonic speeds. The NASA X-43 set a jet-powered speed record in 2004, reaching Mach 9.7. Rocket motors make thrust by burning fuel with an oxidizer. They push out gas through a nozzle. Rocket aircraft carry their own oxidizer, while jets take it from the air. During World War II, the Germans used the Me 163 Komet, a rocket-powered aircraft. The Bell X-1 became the first plane to break the sound barrier in level flight in 1948. The North American X-15 set many speed and altitude records in the 1960s. Some rocket planes are designed as spaceplanes, such as SpaceShipTwo, for travel beyond the Earth's atmosphere.

Design and manufacture

Main article: Aerospace manufacturer

Companies usually build airplanes to make many of them for customers. Designing and planning a plane, including safety tests, can take up to four years for small turboprops and even longer for larger planes. Engineers use drawings, math, computer simulations, wind tunnel tests, and past experience to predict how the plane will behave. When the design is ready, the company builds a few prototypes for testing on the ground. A representative from an aviation agency often watches the first flight. Flight tests continue until the plane meets all the requirements. Then the country's aviation agency allows production to begin. In the United States, this agency is the Federal Aviation Administration (FAA). In the European Union, it is the European Aviation Safety Agency (EASA). In the United Kingdom, it is the Civil Aviation Authority (CAA). In Canada, it is the Civil Aviation Authority of Transport Canada. Welded parts for aerospace and defense must meet very strict safety rules. Nadcap sets global quality standards for aerospace engineering.

When planes are sold to other countries, the country where the plane will fly must also approve it. For example, Airbus planes need FAA approval to fly in the United States, and Boeing planes need EASA approval to fly in the European Union. Rules have also been made to make engines quieter. This is because air traffic over cities near airports can make a lot of noise pollution. Some people build small planes at home as homebuilt aircraft, sometimes from kits of parts. Few companies make planes on a large scale. Instead, dozens or even hundreds of companies make the parts, which are sent to the main factory for assembly. Finished planes are carefully inspected and go through flight tests to check that all systems work and that the plane handles well. The plane may then be customized for a customer's needs.

Characteristics

The main frame of an airplane is called the airframe. Early planes were mostly made of wood with fabric on the wings. As engines and speeds got better, more parts were made of metal. Today, composite materials are also used. The large wings have a curved airfoil shape, like a bird's wing. As the plane moves forward, the wings push air downward. This creates lifting force, which holds the plane up. The wings also help keep the plane steady from roll. Wings come in different designs. A monoplane has one wing level. A biplane has two wings stacked on top of each other, and a triplane has three. The delta wing and swept wing shapes help planes fly faster. A variable-sweep wing can change shape during flight.

The fuselage is the long, thin body of the plane. It is usually shaped with pointed or rounded ends so air flows smoothly around it. The fuselage aerodynamically helps the plane move through the air. It holds the flight crew, passengers, cargo or payload, fuel, and engines. Pilots fly the plane from a cockpit. At the tail, a vertical stabilizer helps control yaw. It holds the rudder. A horizontal stabilizer or tailplane helps control pitch. It holds the elevators. The landing gear supports the plane on the ground. On water, floats support it instead. Some designs are unusual. A flying wing has no clear fuselage. A blended wing body joins the wings smoothly into the body. A lifting body makes lift with its body. Some planes also have a [canard](/wiki/Canard_(aeronautics) foreplane ahead of the main wing. Airplanes use flight control systems and cockpit instruments to help pilots fly safely.

Further information: Fixed-wing aircraft § Aircraft controls, and Fixed-wing aircraft § Cockpit instrumentation

Safety

Main article: Aviation safety

When safety is measured by distance traveled, air travel is about 10 times safer than travel by bus or train. However, when safety is measured by each trip, air travel is more dangerous than travel by car, train, or bus. For this reason, insurance for air travel is fairly expensive, because insurers usually look at the risk for each trip.

There is also a big difference between airliners and smaller private planes. Using the same kind of measure, airliners are 8.3 times safer than smaller planes.

Environmental impact

Main article: Environmental impact of aviation

Like many things that burn fuel, planes that run on fossil fuel release soot and other pollutants into the air. They also make greenhouse gases, such as carbon dioxide (CO₂). Large jet airliners that fly high, near the tropopause, release particles and leave contrails. These can help more cirrus cloud form. Cloud cover may have grown by up to 0.2% since aviation began. These planes can also release nitrogen compounds, which react with ozone and increase the amount of ozone in the air.

Most small piston planes burn avgas, which contains tetraethyllead (TEL). Some piston engines with lower compression can run on unleaded mogas. Turbine and diesel engines do not need lead, and some newer light aircraft use them. Some electric aircraft that do not pollute are already being made. Airplanes also cause noise pollution, mostly when they take off and land.