How does a Parachute Work

The Parachute:
The word parachute comes from a French-Latin mix – 'para', which is Latin for 'against' and 'chute' which is French for 'fall'. So parachute means 'against the fall', which is pretty much how it does work.

A parachute is a light-weight device – made formerly of linen, canvas and silk, and now of nylon and zero-porosity fabrics – that is meant to slow down the fall of people and objects. It is used both as a safety measure in case of an air accident, for safety plus recreational purposes as with skydivers, for military use, and for aid purposes like when dropping food, medicines, heavy machinery and other items to disaster/war affected areas.

History of the Parachute:
The idea of a parachute has been around for quite a long time. People in Ancient China experimented with large parasols. In 9th century Cordoba, the Arab Arman Firman had the idea that if he jumped from a high place wearing a billowing cape, he would have a safe landing. So he tried it from a tower in the town and luckily didn't get himself killed. He had added wooden struts to his cape, which perhaps may have helped slow his fall, but not to any great workable extent.

Designers during the Italian Renaissance also pondered over the possibility of parachutes and we have an extant example of a conical parachute drawn sometime in 1470 or thereabouts by an anonymous artist. We also have Leonardo da Vinci's parachute drawings that were done in Milan around 1480-1483 – his parachutes too were of a conical shape - he either took inspiration from the previous artists or came up with the similar concept himself. His drawings show a pyramidal parachute framed with a wooden square and he seems to have been convinced that the concept would work out, but there is no evidence that he tried this out himself or ever hired someone else to take the fall.

The first time that a parachute was actually made and tried out with some measure of success was in 1617 when the Croatian inventor Faust Vrančić/Fausto Veranzio, who had studied da Vinci's sketches and designed a parachute of his own – called Homo Volans - for his 1595 book on mechanics 'Machinae Novae', jumped from a Venetian tower. I'm not certain how safely he landed – he died that same year, aged 66.

The modern parachute was invented in 1783 by the Frenchman Louis-Sébastien Lenormand, but its use as a safety measure was explored by another Frenchman Jean-Pierre Blanchard. Blanchard was interested in hot air balloons, which were rather attracting public imagination then, and he wanted something to minimize the risks involved. So he experimented by parachuting a small dog from a balloon in 1785. The dog's fate is shrouded in history, but, given Blanchard's continued interest in parachutes, it probably had a non-parachute-related end. In 1793, Blanchard had the chance to try parachuting himself – with his balloon on fire, the decision was actually forced on him. He landed safely and went on to design a new parachute made of folded silk. Silk was strong and lightweight, so, in short, very feasible for parachutes.It was used for making parachutes right up until modern times.

Another Frenchman, Andre Jacques Garnerin, made a parachute jump over Paris from a balloon in 1797. and then went on to make a series of exhibition jumps – that is, jumping to entertain the crowds below.

With the arrival of the airplane, there was a renewed interest in parachutes. U.S. Army Captain Albert Berry was the first person to parachute from a plane. Parachutes were used in the First World War as a rescue device for observers who scanned enemy territory from hot-air balloons, and began to be used widely by fliers during the Second World War. Modern day parachutes, with improved design and material, are used for assorted purposes.

How the Parachute Works:
A parachute works on the principle of 'air resistance'. To understand this principle, try two things. Drop a stone and drop a feather from a certain height. You will see that the stone plummets down instantly, while the feather kind of floats down. When an object falls through the air, it basically creates a path by pushing aside the atoms and molecules in the air. A stone, with its heavy mass, has no problem doing this and so drops to the ground quickly. But a feather, which has little mass and a larger surface area, finds it harder to shove aside the atoms and molecules and this interference slows down its downward fall. This is exactly how a parachute operates – getting the air molecules to slow down the fall and thus make it safer.

A parachute is packed in a deployment bag or D-bag. The D-bag is placed in a container which is secured by a closing pin. Packing a parachute correctly is very important – when deployed the parachute must unfold in a dependable and systematic way, without twisting or tangling the lines, and at an unhurried pace – if it opens too fast, the sudden decrease in speed can hurt the parachutist and there is also a chance of the equipment getting damaged. For this reason, specially trained and certified people are required to pack parachutes. And parachutes not often in use need to be unpacked and refolded regularly to keep them in good order.

This is how a parachute deploys -

• After the parachutist jumps, he/she releases a small parachute known as the drogue chute from the parachute container's bottom pouch.
• The drogue chute flares open and this action pulls out a very long and strong nylon strip called the bridle.
• As the bridle is pulled out, it releases the closing pin, opens the container and pulls out the deployment bag.
• When the deployment bag is pulled out, the parachute lines unfold and unravel out.
• The unraveling parachute lines in turn pull out the strong connecting straps (the risers) between the lines and the container.
• Finally the parachute canopy itself is pulled out.
• As the parachute opens, a nylon slider slides down the billowing lines. The slider helps in holding the lines together, keeps them from getting entangled and also prevents the parachute from opening too fast.
• Once the parachute has opened – deployed – correctly, the parachutist can land safely.

Sometimes, for unforeseen reasons, a parachute may not open correctly or the lines may break. So, as an additional safeguard, parachutists carry a reserve parachute. Many parachutes nowadays also include an automatic activation device (AAD), which is a small computer programmed to open the reserve parachute at a certain altitude. So in case the parachutist becomes confused or loses consciousness and can't open the main chute, he/she can still count on the reserve chute saving the day.