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Kinds of airplanes
People build airplanes that fly at different speeds and do different kinds of work.
Airliners are big planes used by airline companies. Most airlines carry passengers and some cargo, or products. Most airliners fly 500 to 600 miles (800 to 970 kilometers) per hour. The fastest planes are supersonic -- faster than sound. They travel up to 1,350 miles (2,180 kilometers) per hour.
The biggest airliners have four jet engines. Smaller three-engine and twin-engine airliners make shorter flights. Some smaller planes have engines with propellers instead of jet engines. Propellers are rotating blades.
Light planes are small planes with two to six seats. They can take off and land at small airports.
Most light planes have propellers. Some belong to people who use them to travel. Others are used for special jobs. For example, people use them to inspect power lines, fight forest fires, plant seeds, deliver cargo, take pictures from the air and teach students to fly.
Military planes do many kinds of work for the armed forces. Bombers attack targets on the ground. Fighters attack other planes in the air. Fighter-bombers can do both.
Special purpose planes do unusual kinds of work. Seaplanes can take off and land in water. Spray planes are used to spray fertilizer or insect spray on crops.
The parts of an airplane
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Almost all planes have the same main parts. They have a wing, a main section called a fuselage, a tail, landing equipment, and an engine.
The wing sticks out from the sides of the fuselage. It is nearly flat on the bottom and curved on the top. This shape helps create the airflow that raises the plane off the ground and keeps it in the air.
Image to right: This drawing shows the parts of a light airplane called a Piper Cherokee. Credit: World Book illustration by Tom Morgan
Most airplane wings have moving parts that help balance the plane. The ailerons are hinged pieces on the back of the wing. They make the plane bank, or tilt, and turn. Many planes also have flaps that help the plane lift up for takeoff and slow down for landing.
The wing also carries navigation lights. A red light on the left wing tip and a green light on the right wing tip show which way the plane is traveling. Often the engines are on or in the wing.
The fuselage contains the controls, the crew, the passengers, and the cargo. In many small planes, the pilot and passengers sit in the same cabin. Large planes have a cockpit for the pilot and crew and a cabin for passengers and cargo.
The tail is the rear part of the airplane. It helps guide the plane and keep it balanced. Like the wing, it has parts that move. The rudder is a hinged plate on the back of the fin, the upright part of the tail. It helps the plane turn left or right. A flap called the elevator helps raise or lower the plane's nose. It is connected to the stabilizer, which is the part of the tail that looks like a small wing.
All planes have landing gear for taking off and landing. On high-speed planes, the landing gear is pulled up when the plane is flying.
The controls are in the cockpit. Most planes have a yoke, or wheel, for steering. Some planes, such as spray planes, are steered with a stick. Planes also have rudder pedals, engine instruments, and flight instruments that show the plane's height and speed. Three kinds of engines are used in airplanes. Piston engines are like car engines. The power from the engines turns propellers that move the plane through the air.
Jet engines take in air and burn it with fuel. The exhaust, or gases, from the engines creates a huge backward push that drives the plane forward. The exhaust also spins a device called a turbine, with runs the other parts of the engine.
Rocket engines work much like jet engines, but they do not need to take in oxygen.
How planes fly
Gravity is a force that pulls planes toward the Earth. So in order to fly, a plane's wing must create a lifting force that is stronger than gravity.
The lift is made by the air pressure over and under the plane's wing. As a plane moves forward, the air moving over the curved top of the wing travels farther than the air moving under it. It also travels faster. This makes the air pressure above the wing drop. Then the stronger pressure under the wing lifts the plane.
In order to lift, the plane needs to move. The jet engine or the propeller makes the plane move forward so it can take off.
To climb, or go higher, the pilot increases the engine power. To descend, or go lower, the pilot decreases the engine power. To turn, the pilot banks the plane.
History of airplanes
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During the 300s B.C., the Chinese discovered how to make kites. Later, large kites lifted people into the air.
In 1783, two French brothers, the Montgolfiers, made a hot-air balloon. Two other Frenchmen floated over Paris in it. This was the first human flight.
Image to right: The Flyer was the world's first successful airplane. This propeller plane was built and flown by the Wright brothers in 1903. Credit: World Book illustration by Tom Morgan
During the 1800s, many people experimented with gliders. They began to add engines and propellers but these early machines could not be flown. After experimenting with gliders, two brothers, Orville and Wilbur Wright, built a double-winged planed. On Dec. 17, 1903, Orville Wright successfully flew it near Kitty Hawk, North Carolina. After that, many inventors built and flew planes.
Jet planes were developed during World War II (1939-1945). After the war, airliners began to use jet engines.
How to cite this article: To cite this article, World Book recommends the following format: "Airplane." The World Book Student Discovery Encyclopedia. Chicago: World Book, Inc., 2005.
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