Parachute Materials - Parachute Fabric

A parachute is a device which decelerates the fall of an object in the mid atmosphere by creating a drag. The simple equipment works on the basic principle of 'air resistance' and 'gravity', and is used in rescue work, recreational activities and extreme sports too.

The main components of a parachute includes thin fabric, suspension lines and support tapes. These suspension lines are gathered through the metal connector links located at the end of strong straps known as the 'risers'. These risers are attached to the harness, which contains the load. As the thin fabric is inflated, air gets trapped within the material and makes the parachute fabric stretch outwards and resist the fall. At the same time the person using the parachute pulls the chute down with his weight. Both the activities, which happen simultaneously produce a drag, due to which the speed at which the parachute comes down is decreased considerably, and instead of falling with an impact the person smoothly lands on the ground.

Parachute Materials
The material used in the parachute plays a vital role in its functioning. The foremost property of the material which is chosen to make a parachute should be its resistance to wind. Only a windproof material can sustain the winds blowing at such high altitudes. Another important property is the density of the material. Density and time taken to complete the fall have a direct relationship, i.e. denser the material of the parachute, faster will be the speed at which the chute will come down. Rigidity of the material also plays an important role in determining the time taken to complete the fall. Rigidity directly affects the shape of the parachute, and shape in turn affects the stability. If the parachute is stable, it will descend slowly, but if it swings owing either to the shape or the movement of the parachutist, it will lose air and come down at a greater speed. The texture of the parachute fabric also affects the drag, but the impact is minimal.

The canopy of the parachute was initially made of canvas, and eventually replaced by silk. Silk, being thinner, lighter, stronger, fire resistant and easily foldable, proved to be a better material than canvas. In late 1930s and early 1940s, the United States was not able to import silk required to make parachutes, owing to ongoing World War. During this phase the innovators came up with an idea of replacing silk with nylon. This proved to be beneficial, as nylon had good elasticity, was resistant to mildew, and relatively less expensive.

Although nylon still remains 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, has also been used to make parachutes. The nylon fabric used in parachute is woven in a specialized manner, with extra thick thread, to create a pattern on small squares. The technique proves to be helpful when the canopy experiences small tears, as these small squares avoid the tears from spreading. Even the harness straps and the suspension lines are made of nylon. The ripcord, pulled to open the parachute, is made from stainless steel cable. Forged steel, coated with cadmium, is used to manufacture the metal connectors used to gather the suspension lines. This cadmium coat prevents the connectors from rusting.

The descent of the parachute largely depends on the parachute material, therefore it is important that the material chosen is windproof, light, flexible and has a fine texture. At the same time being inexpensive and abundantly available will also add to its benefits. The parachute canopy has come a long way from plain canvas material to Kevlar, a strong synthetic fiber. May be we will have even better parachute materials someday, but right now the stakes are on nylon, as it covers all the required necessities for a good parachute fabric.