Published: February 21, 2021
How Does a Parachute Work?
A parachute works by forcing air into the front and creating a structured 'wing' under which the passenger can fly. Parachutes are controlled by pulling down on steering lines which change the shape of the wing, causing it to turn or to increase or decrease its rate of descent.
Modern skydiving parachutes are 'square' in shape - to look at, they're more like rectangles. This is different to parachutes of old which were round.
The change in shape has enabled skydivers to have much more control over their parachutes. Today, parachute pilots can turn their parachutes, change their rate of descent, flatten their glide and lots more to make parachute landings more accurate than ever.
How Parachutes Fly
Parachutes are a 'semi-rigid wing'. This means that, while they are flying, they are pretty much solid - in fact, skydivers are able to bump their parachutes against each other and even walk over the top of them in a discipline called CRW, or canopy relative work.
If you looked at a parachute from the front, you'd see it is made up if either seven or nine 'cells'. Essentially, the full parachute is actually a series of separate chambers, all of which catch air and work together to make the full wing.
The front of each 'cell' is open and this is where the air enters. As the parachute is flying forwards, air is rammed in through the front and caught inside the cells, giving the parachute its shape. Modern parachutes are also referred to as 'ram air parachutes' for this reason.
How Parachutes Open
The first step to successfully piloting a parachute is to have it open in the first place!
Parachutes are packed into their containers in such a way that the cells are pointing forward as the parachute deploys, allowing air to rush into it straight away. This process means parachute open efficiently and, usually, on heading. Slight variances in the way it is packed can result in off-heading openings, but the design of the parachute means it will always fly front first.
How Parachutes Turn
Parachutes are connected to their containers by lines, which are basically strong string or rope which attaches at various points across the parachute's underside.
The steering lines are situated to the back of the parachute. Their purpose is to allow the skydiver to pull down on one side or both to make the parachute turn. Pulling down on the right steering toggle will make the parachute turn right, pulling down on the left makes it turn left and pulling both makes the canopy slow its rate of descent by flattening it out.
The steering lines have 'toggles' attached to the bottom of them, giving the skydiver handles on which to hold for ease of control.
How Parachutes Descend
The design of parachutes means they descend at a manageable rate toward the ground. Flying a parachute feels like gliding through the air, always getting lower but doing so in a calm way that makes parachute flight a very relaxing experience.
That' assuming we're not doing anything to change that flight characteristic. When a skydiver uses the toggles to pull down on the steering lines to make the parachute turn, it descends a little faster. Much more advanced parachute pilots use a technique called 'swooping' which increases their rate of descent much more and creates a swooshing sound as they come in to land.
How Parachutes Land
As the skydiver comes into land, they use the steering toggles to steer them to the safe landing area. At this point, they need to slow the parachute's descent rate to its minimum, meaning they are able to gently touch down on the ground.
To do this, they pull down on both steering toggles in a controlled yet assertive manoevre called 'flairing'. This pulls down on the back of the parachute, causing it to flatten out and reducing its descent rate to almost nothing. Touchdown is usually a gentle step forward, and the parachute then collapses to the ground as the air stops rushing into it.
All skydivers jump with two parachutes; a main and a reserve. The reason for this is safety; while the main parachute will work 999 times out of 1,000 as a rough average, there is still a chance of things not going to plan. This might be due to user error during the packing process, or a problem with the parachute itself.
All precautions are taken to avoid any issue, but by jumping with two parachutes, skydivers always take a backup.
Parachute packing is an essential skill for experienced skydivers. Becoming a certified parachute packer is part of the skydiving license process. Only certified parachute packers are able to pack parachutes for themselves and others.
Packing the reserve parachute is a slightly different, much longer, process that alleviates almost all risk of the reserve parachute failing to function.
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» Ken K.