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. The use of the parachute was first 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, and in 1793 claimed to have made the first successful human parachute descent. After this time parachutes became a regular part of the equipment of balloonists, and after World War I were adopted as lifesaving devices for the pilots and passengers of aeroplanes.

A parachute designed for human use is typically a canopy about 7.3 m (24 ft) in diameter, composed of about 25 panels, or gores, of nylon or silk. The canopy has a small vent hole in its centre, which is normally held closed by elastic bands but which 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 smaller parachute, which is ejected from the pack when the rip cord is pulled and which drags 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 seconds. 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 has opened, jumpers descend at a rate of about 5.2 m (17 ft) per second, and strike the ground with less force than if they 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 subsequent wars parachutes have been used 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, aeroplanes, and sports cars. In the 1970s sports parachuting, or skydiving became popular.