Description

A parachute is a recreational, sporting, or military device used to slow the descent of falling object or person. The word is derived from the French word "para" which means to shield and the French word "chute" which means to fall.

Modern parachutes are most often ram-air parafoils parachutes. These parachutes are specially designed to allow air to flow through the parachute that creates lift. The ram-air parafoil parachute gets its name from the aerodynamic principals of the air-foil.

History

The first written account of a parachute design was found in Leonardo da Vinci (1452-1519) sketchbook dating back to 1495.

Fauste Veranzio built a device similar to Leonardo’s which he used to jump from a tower in Venice, Italy in 1617.

The Montgolfier brothers successfully dropped animals from their hot-air-balloons in 1783 utilized an early version of the parachute.

All of the parachute devices prior to 1783 were designed using a rigid frame covered in cloth. It wasn’t until Sebastian Lenormand jumped from a tower in 1783 at the Montpelier Observatory in Paris that a device was used that looked similar to the modern parachute. Lenormand constructed his device from a round 14’ piece of linen cloth. Lenormand named the device a parachute.

Jean Pierre François Blanchard (1753–1809) is credited with bringing popularity to parachuting. His fame as a hot-air-balloonist was established when he became the first to pilot a balloon across the English Channel in 1785. He soon began experimenting with parachuting by dropping a dog from his balloon. Between 1797 and 1802, Blanchard became well known for his high altitude jumps in a basket suspended beneath a parachute. His highest jump was from 7900 feet (2400 meters). Blanchard is credited with being the first to use a folded parachute made of light-weight silk.

The first recorded emergency jump with a parachute was from a burning hot-air-balloon on July 14, 1808 by Jordaki Kuparento, a Polish balloonist, over Warsaw, Poland.

In the early 1960’s, American parachutist Pierre Lemoigne was successful in cutting slots in the round parachute canopy to allow for air to flow through the canopy. This had a dramatic effect on the lift to drag ratio and allowed for the pilot to steer the chute in a predictable manner.

In 1964, Domina Jalbert of Florida invented a square canopy called the Ram Air Para Foil. The Ram Air worked by allowing air to pass through the double surface glider allowing for better maneuverability and increased lift. The Ram Air is the most popular sporting parachute today. The Ram Air is used in many air sports such as paragliding, powered parachuting, powered paragliding and skydiving.


Construction

The major parts of the parachute are the canopy, the risers, the container, and the suspension lines.

Canopies are made from a soft fabric such as woven nylon. They come in a variety of shapes ranging from square to round.

When the canopy is not in use it is stored in a container. Skydivers strap the container onto their body with the canopy inside. During freefall the skydiver pulls a rip-cord that releases the canopy from inside the container. The container is also known as a harness.

Directly attached to the container/harness are the risers. The brakes/steering lines are attached to the rear risers. Risers are made from heavy-duty thick fabric.

At the top of the risers are the suspension lines. These lines run from the riser to the canopy. They are often made from Spectra or Vectran which provide little or no stretch.

Control

Parachutes can be steered by pulling on one or both of the brake lines that are attached to the rear risers. Pulling on one of the brake lines causes a turn.

When landing, the pilot will pull on both of the risers simultaneously to increase the angle of attack. The increase in the angle of attack will slow the forward momentum of the parachute. The action of pulling both brake lines during landing is called 'flaring' the chute.


Applications


Photo Credit:
NASA
Parachutes are used for a variety of reason but are most commonly used in skydiving. Skydivers generally leave the aircraft between 3000 feet (900 meters) and 13,000 feet (4000 meters). After a brief freefall the skydiver will deploy the chute and begin to pilot the parachute to the drop zone.

Parachutes are also commonly used for military operations. Most modern militaries have special forces that are deployed behind enemy lines through the use of parachutes. These 'paratroopers' often leave the aircraft at altitudes of 500 feet (150 meters) or less. The chute is deployed by the use of a static line that is attached to the aircraft.

A less common use of a parachute is during disasters. When disaster strikes in remote areas, the use of a parachute can be used to drop logistics into devastated areas that are hard to reach by other means.

Parachutes can also be used to slow the forward momentum of an aircraft of race car. Chutes used to brake the forward momentum are called 'drag chutes' or 'drogue chutes'. The space shuttle brakes with the use of a drag chute after it lands.

Besides skydiving, modified version of the parachute are used in other air sports such as paragliding, powered parachuting, and powered paragliding. The designs are based upon the Ram Air Parafoil design but differ from skydiving parachutes. Skydiving parachutes are designed to handle an impact load when the skydiver deploys their chute at 125 mph. In paragliding, the chute is designed to be more aerodynamic with a better lift to drag ratio. Powered parachutes are designed to carry a large load.