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Parachute material evolution
The descent of a parachute largely depends on the material, and therefore it is important that the material chosen is windproof, light, flexible, and has a fine texture.
A parachute is an equipment which decelerates the fall of an object in the mid atmosphere by creating a drag. It works on the basic principle of 'air resistance' and 'gravity', and is used in rescue work, recreational activities and extreme sports. The fabric canopy, suspension lines and support tapes are the main components of a parachute; and all of these are made from specialized material.
When the parachute is deployed, air gets trapped inside the canopy, thus making the parachute fabric stretch outwards and resist the fall. At the same time, the person using the chute pulls it down with his weight. Both the activities happen simultaneously and produce a drag, which reduces the speed at which the parachute comes down; and instead of falling with an impact, it smoothly lands on the ground.
What is the Parachute Made From?
Parachute Fabric
When the parachute is deployed, air gets trapped inside the canopy, thus making the parachute fabric stretch outwards and resist the fall. At the same time, the person using the chute pulls it down with his weight. Both the activities happen simultaneously and produce a drag, which reduces the speed at which the parachute comes down; and instead of falling with an impact, it smoothly lands on the ground.
Denser the material of the parachute, faster will be the speed at which the chute will come down.
The rigidity of the material plays is an important role in determining the time taken to complete the fall. It directly affects the shape of the parachute, which, in turn, affects the stability.
If the parachute is stable, it will descend slowly, but if it swings, it will lose air and come down at a greater speed. Other than the shape, the parachute may also start swinging as a result of the movement of the parachutist. The texture of the parachute material also affects the drag, but the impact is minimal.
Canvas, Silk and Nylon
The canopy of the parachute was initially made of canvas, which was eventually replaced by silk, which was thinner, lighter, stronger, fire resistant and easy-to-fold. In late 1930s and early 1940s, the World War affected silk import in the United States.
In order to counter the shortage of silk, innovators tried using different materials to make parachute canopy, and finally came up with the idea of replacing silk with nylon. The fact that it had good elasticity, it was resistant to mildew, and was relatively less expensive, worked in its favor.
The nylon fabric used in parachute is woven in a specialized manner, with extra thick thread, to create a pattern of small squares. The technique proves helpful when the canopy experiences small tears, as these small squares avoid the tears from spreading.
Being strong, flexible, and light, nylon is also used to make harness straps and suspension lines of the parachute. Forged steel is used to manufacture the metal connectors used to gather the suspension lines. This forged steel is coated with cadmium to prevent the connectors from rusting.
Interesting Fact
The 51 ft diameter parachute used by NASA for its Mars Science Laboratory mission was made from nylon and polyester, and weighed a mere 120 lbs.
Though nylon continues to be the first choice for parachute canopies, more recently Terylene (a variety of polyester fabric) and Kevlar (a strong and heat resistant synthetic fiber) have also been used for the same. The canopy of a parachute has come a long way from plain canvas material to Kevlar, and it wouldn't be surprising if we have a better fabric at our disposal in future. Right now though, the stakes are on nylon; and it fulfills all the requirements of a good parachute canopy fabric.