Parachute

Parachute (French para,”preventing”; chute,”fall”), large, umbrella-shaped fabric canopy used to reduce the speed of a person or object falling through the air, and carried as an escape device in aircraft. Parachute use may have occurred in China by the 1100s. The use of the parachute was also suggested by Leonardo da Vinci, but the first practical parachute was invented in the 1780s. The French aeronaut Jean Pierre Blanchard dropped a dog equipped with a parachute from a balloon in 1785. Twelve years later, on October 22, 1797, André-Jacque Garnerin jumped from a hot air balloon over Parc Monceau in Paris and descended using a cloth parachute. After this time parachutes became a regular part of the equipment of balloonists, and after World War I they were adopted as lifesaving devices for the pilots and passengers of airplanes.

A parachute designed for human use is typically a canopy about 7.3 m (about 24 ft) in diameter composed of about 25 panels, or gores, of nylon or silk. The canopy has a small vent hole in its center that is normally held closed by elastic bands but that expands when the canopy opens, so as to lessen the initial shock of deceleration. So-called shroud lines are sewn into the seams between the panels, passing over the top of the canopy, and are connected at their ends to two metal rings. The parachutist is equipped with a harness of strong webbing that passes over the shoulders, around the body, and between the legs; this harness, in turn, is attached to the rings. When not in use, the parachute is folded compactly into a canvas container worn by the parachutist. The pack is so arranged that it flies open with the aid of rubber bands and metal springs when a metal closing line called the rip cord is pulled. The parachute is also equipped with a small parachute, which is ejected from the pack when the rip cord is pulled and which pulls the main parachute out of the container.

A parachutist dives, jumps, or steps from the plane and pulls the rip cord after an interval of about 3 sec. This interval enables the parachutist to fall far enough to ensure that the parachute will be clear of the plane when it opens. Once the parachute opens, the jumper descends at a rate of about 5.2 m (about 17 ft) per sec and strikes the ground with about the same force as if he or she had jumped freely from 3 m (10 ft).

During World War II, armies made extensive use of paratroops, or parachute troops, who were often flown behind the enemy lines in transport planes; they were usually landed from low altitudes and their parachutes were arranged to open automatically, as the soldiers jumped, by means of long straps attached to the carrying plane. In the Korean War the U.S. Air Force also used parachutes to drop heavy equipment, such as tanks, trucks, and field guns. The canopy of a heavy-equipment parachute may measure up to 30 m (100 ft) in diameter.

The design of parachutes has become increasingly sophisticated; especially designed parachutes control the rate of descent, reduce the effect of winds, and maintain stability according to the weight and shape of the object being carried. Other parachutes, called drogue chutes, are used to decelerate spacecraft, experimental rockets, airplanes, and sports cars. In the 1970s sport parachuting, or skydiving, became popular.