what are the uses of parachutes?

Question

i want to know the different applications of parachutes in variety of situations

Answer 1

Types of parachutes:

Round parachutes:

An American paratrooper using an MC1-1C series 'round' parachuteRound parachutes, which are pure drag devices (i.e., they provide no lift like the ram-air types), are used in military, emergency and cargo applications. These have large dome-shaped canopies made from a single layer of cloth. Some skydivers call them "jellyfish 'chutes" because they look like dome-shaped jellyfish. Rounds are rarely used by skydivers these days. The first round parachutes were simple, flat circulars, but suffered from instability, so most modern round parachutes are some sort of concial (i.e Strong 26 foot diameter Mid-Lite found in pilot emergency parachutes) or parabolic (picture a flat circular canopy with an extended skirt) US Army T-10 parachute used for static-line jumps

Some round parachutes are steerable, but not to the extent of the ram-air parachutes. An example of a steerable round is provided in the picture of the paratrooper's canopy; it is not ripped or torn but has a "T-U cut". This kind of cut allows air to escape from the back of the canopy, providing the parachute with limited forward speed. This gives the jumpers the ability to steer the parachute and to face into the wind to slow down the horizontal speed for the landing.


Annular & pull down apex parachutes:

A variation on the round parachute is the pull down apex parachute - invented by a Frenchman named LeMoigne - referred to as a Para-Commander-type canopy in some circles, after the first model of the type. It is a round parachute, but with suspension lines to the canopy apex that applies load there and pulls the apex closer to the load distorting the round shape into a somewhat flattened or lenticular shape.

Often these designs have the fabric removed from the apex to open a hole through which air can exit, giving the canopy an annular geometry. They also have decreased horizontal drag due to their flatter shape, and when combined with rear-facing vents, can have considerable forward speed around 10 mph (15 km/h).


Ribbon and ring parachutes:

Ribbon and ring parachutes have similarities to annular designs, they can be designed to open at speeds as high as Mach 2 (two times the speed of sound). These have a ring-shaped canopy, often with a large hole in the center to release the pressure. Sometimes the ring is broken into ribbons connected by ropes to leak air even more. The large leaks lower the stress on the parachute so it does not burst when it opens.

Often a high speed parachute slows a load down and then pulls out a lower speed parachute. The mechanism to sequence the parachutes is called a "delayed release" or "pressure detent release" depending on whether it releases based on time, or the reduction in pressure as the load slows down.


Ram-air parachutes:

Most modern parachutes are self-inflating "ram-air" airfoils known as a parafoil that provide control of speed and direction similar to paragliders. Paragliders have much greater lift and range, but parachutes are designed to handle, spread and mitigate the stresses of deployment at terminal velocity. All ram-air parafoils have two layers of fabric; top and bottom, connected by airfoil-shaped fabric ribs. The space between the two fabric layers fills with high pressure air from vents that face forward on the leading edge of the airfoil. The fabric is shaped and the parachute lines trimmed under load such that the ballooning fabric inflates into an airfoil shape.



Personnel parachutes:

A U.S. NAVY display jumper landing a 'square' ram-air parachute
Reserves
Paratroopers and sports parachutists carry two parachutes. The primary parachute is called a main parachute, the second, a reserve parachute. The jumper uses the reserve if the main parachute fails to operate correctly.

Reserve parachutes were introduced in World War II by the US Army paratroopers, and are now almost universal. For human jumpers only emergency bail-out rigs have a single parachute and these tend to be of round design on older designs while modern PEPs (i.e P124A/Aviator) contain large, docile ram-air parachutes.


Deployment:
Reserve parachutes usually have a ripcord deployment system, but most modern main parachutes used by sports parachutists use a form of hand deployed pilot chute. A ripcord system pulls a closing pin (sometimes multiple pins) which releases a spring-loaded pilot chute and opens the container, the pilot chute is propelled into the air stream by its spring then uses the force generated by passing air to extract a deployment bag containing the parachute canopy, to which it is attached via a bridle. A hand deployed pilot chute once thrown into the air stream pulls a closing pin on the pilot chute bridle to open the container then the same force extracts the deployment bag. There are variations on hand deployed pilot chutes but the system described is the more common throw-out system. Only the hand deployed pilot chute may be collapsed automatically after deployment by a kill line reducing the in flight drag of the pilot chute on the main canopy. Reserves on the other hand do not retain their pilot chutes after deployment. The reserve deployment bag and pilot chute is not connected to the canopy in a reserve system, this is known as a free bag configuration and the components are often lost during a reserve deployment. Occasionally a pilot chute does not generate enough force to either pull the pin or extract the bag, causes may be that the pilot chute is caught in the turbulent wake of the jumper (the "burble"), the closing loop holding the pin is too tight, or the pilot chute is generating insufficient force, this effect is known as "pilot chute hesitation" and if it does not clear in can lead to a total malfunction requiring reserve deployment.

Paratroopers' main parachutes are usually deployed by static lines which release the parachute yet retain the deployment bag which contains the parachute without relying on a pilot chute for deployment, in this configuration the deployment bag is known as a direct bag system, the deployment is rapid, consistent and reliable. This kind of deployment is also used by student skydivers going through a static line progression, a kind of student program.


Varieties of personal ram-airs:

Personal ram-air parachutes are loosely divided into two varieties: rectangular or tapered commonly referred to as 'squares' or 'ellipticals' respectively. Medium-performance canopies (reserves, BASE, canopy formation and accuracy) are usually rectangular. High performance ram-air parachutes have a slightly tapered shape to their leading and/or trailing edges when viewed in plan form and are known as ellipticals. Sometimes all the taper is in the leading edge (front). Sometimes all the taper is in the trailing edge (tail). These are usually only used by sports parachutists. Ellipticals often have smaller, more numerous fabric cells and are shallower in profile. Elliptical canopies can be anywhere from slightly elliptical to highly elliptical indicating the amount of taper in the canopy design and this is often an indicator of the responsiveness of the canopy to control input for a given wing loading and the level of experience required to pilot the a canopy safely.

The rectangular parachute designs tend to look like square inflatable air-mattresses with open front ends. They are generally safer to operate because they are less prone to dive rapidly with relatively small control inputs and they are usually flown with lower wing loadings per square foot of area, and glide more slowly. They typically have a less-efficient glide ratio.

Wing-loading of parachutes is measured the same way as aircraft: comparing the number of pounds (exit weight)to square footage of parachute fabric. Typical wing-loadings for students, accuracy competitors and BASE jumpers are less than one pound per square foot (i.e. 0.7 pounds per square foot). Most Student skydivers fly with wing-loadings below one pound per square foot. Most sport jumpers fly with wing loadings between 1.0 and 1.4 pounds per square foot, but many interested in performance landings exceed this wing loading. Professional Canopy pilots compete at wing-loadings of 2 to 2.6 pounds per square foot. While ram-air parachutes with wing loadings higher than four pounds per square foot have been landed, this is strictly the realm of professional test jumpers.

Smaller parachutes tend to fly faster for the same load and ellipticals respond faster to control input. Therefore, small elliptical designs are often chosen by experienced canopy pilots for the thrilling flying they provide. Flying a fast elliptical requires much more skill and experience. Fast ellipticals are also considerably more dangerous to land. With high-performance elliptical canopies, nuisance malfunctions can be much more serious than with a square design and may quickly escalate into emergencies. Flying highly loaded elliptical canopies is a major contributing factor in many skydiving accidents.

Aspect ratio is another way to measure ram-air parachutes. Aspect ratios of parachutes are measured the same way as aircraft wings, by comparing span with chord. Low aspect ratio parachutes (i.e. span 1.8 times the chord) are now limited to precision landig competitions. Popular precision landing parachutes include Jalbert (now NAA) Para-Foils and John Eiff's series of Challenger Classics. While low aspect ratio parachutes tend to be extremely stable - with gentle stall characteristics - they suffer from steep glide ratios and small "sweet spots" for timing the landing flare.

Medium aspect ratio (i.e. 2.1) parachutes are widely used for: reserves, BASE and canopy formation competition because of their predictable opening characteristics. Most medium aspect ratio parachutes have seven cells.

High aspect ratio parachutes have the flattest glide and the largest "sweet spots" (for timing the landing flare) but the least predictable openings. 2.7 is about the upper limit for parachute aspect ratios. High aspect ratio canopies typically have nine or more cells. All reserve ram-air parachutes are of the square variety because of the greater reliability and less-demanding handling characteristics.


General characteristics of ram-airs:

Main parachutes used by skydivers today are designed to open softly. Rapid deployment was an early problem with ram-air designs. The primary innovation that slows the deployment of a ram-air canopy is the slider; a small rectangular piece of fabric with a grommet near each corner. Four collections of lines go through the grommets to the risers. During deployment, the slider slides down from the canopy to just above the risers. The slider is slowed by air resistance as it descends and reduces the rate at which the lines can spread. This reduces the speed at which the canopy can open and inflate.

The overall design of a parachute still has a significant influence on the deployment speed. Modern sport parachutes' deployment speeds vary considerably. Most modern parachutes open comfortably, but individual skydivers prefer different deployment speeds.

The deployment process is inherently chaotic. Rapid deployments can still occur even with well-behaved canopies. On rare occasions deployment can even be so rapid that the jumper suffers bruising, injury, or death.

Emergency and reserve parachutes by design tend to deploy more rapidly than sports main canopies. They still have sliders, but the sliders descend rapidly, and are constructed with less air-resistance than a sports canopy's slider. For example, one method of reducing the air-resistance of a reserve's slider is to make it of open-mesh fabric.

Answer 2

Parachute Uses

Answer 3

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Answer 4

Before World War II parachutes served mainly as lifesaving devices. During the war specially trained combat troops were parachuted into battle. Today food and medical supplies are often dropped by parachute into areas stricken by disasters such as floods and earthquakes. Life rafts and other survival equipment are lowered by parachute in air-sea rescue operations. …


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Answer 5

The game of Badminton applies parachute principles more so than many ball games e.g. Tennis, squash, table tennis.When served high, the shuttle actually falls after reaching the top rather than go forward!!!

Answer 6

A pilot can jump out of a plane with parachute when he is fedup of flying.

Answer 7

Parachutes are used to drop items or personnel into areas whereby vehicles have no accessibility.

Answer 8

They allow objects, equipment and people to jump out of aircraft and reach the ground usually in one piece. They can also be used by dragsters, jet fighters and other very fast vehicles decelerate very quickly on landing. Sometimes they are used to slow the decent of flares.

Answer 9

to drop items like medicals and life rafts to support peoples lives when nearby transpiration is not available

Answer 10

To help you fly in para-gliding

Answer 11

slowing down race cars, airplanes, for people jumping OUT of airplanes.... it is "applied" to the backside !