The Science Behind Parachutes

How do parachutes work? Reasonable question if you’re about to make a skydive (or even if you’re just interested in learning the mechanics behind skydiving)! After all, if you’re going to launch yourself out of an airplane and put your trust in a big ball of fabric, it helps to know the science behind parachutes.

You’ll be relieved to know they are much more than a haphazard hodgepodge of material and stitches, there’s a fine-tuned design behind it all. How does a parachute work? The simple answer is with the magic of air resistance and human ingenuity.

Here’s a quick science refresher to get us started on our journey to discover how parachutes work.

The strength of gravity pulls us all to Earth uniformly: whether a stone or a feather, no matter the object, it will have an acceleration of 9.8 m/s ² downward to Earth. In a vacuum with no air, you’d see a feather and a stone hitting the ground at the same time. So, how exactly is it that in the real world the stone reaches the ground first? Well, this is where air resistance makes its appearance. The feather hits the ground after the stone not because it’s lighter, but because the feather catches more air as it falls; the drag of its surface area slows it down.

Air Resistance

In part, the science behind parachutes is that they make clever use of air resistance. You see, though it’s invisible, air is composed of gas molecules and as you move around, they’re pushed aside. The larger space you occupy and the larger surface area you have, a greater amount of air resistance results.

To take advantage of this fact, parachutes are often made from a lightweight nylon that has been specially treated to be less porous (that is, it doesn’t let as much air through). This allows your open parachute to create more air resistance and to drift toward the ground slowly and safely.

Terminal Velocity

Terminal velocity is a point at which there can be no further acceleration. This constant speed is reached when the force of gravity is countered and balanced by the resistance of the medium an object is falling through (like air).

How does this apply? Your parachute allows you to descend more slowly because it lowers terminal velocity by increasing your air resistance. Most parachutes are designed to create a large amount of drag and allow you to land at a safe, low speed.

Parachutes Today

Photos by Animare

Parachutes today are designed for a myriad of functions. Military operations utilize a parachute that is dome-shaped, providing only basic steering and are used by the military for the insertion of paratroopers and gear. On the other hand, civilian jumpers most commonly use a rectangular Ram-air parachute, one constructed with a series of tubular cells that inflate as air is forced into each chamber. The result is a semi-rigid, curved airfoil wing that delivers higher performance and increased maneuverability.

Parachute Deployment Systems

All recreational skydivers’ jump equipment contains a dual-parachute system: a main parachute and a reserve parachute (the back-up). These two parachutes are packed within a single backpack-looking apparatus we call the container.

The main parachute is deployed by a miniature chute, known as the pilot chute. At the appropriate altitude, a jumper will extract the pilot chute from the elastic pouch, where it is securely stored, sewn on the bottom of the container. The pilot chute inflates and creates enough force to extract the main parachute from the container. The main parachute is designed to fill with air and inflate in a slow, efficient manner. The reason for the delayed opening is to avoid too much opening shock on the body. Think coming to a slow, steady stop at a red light versus slamming on the breaks.

Now that you’ve got the physics down low to the science behind parachutes, why not let us show you firsthand? Schedule your skydive with Skydive Paraclete XP today.

How Do Skydiving Parachutes Work?

How Do Skydiving Parachutes Work?

There’s very little chance you’ve ever seen an image of a skydiver under more than one parachute. By that figuring, it might be easy to assume that there’s only one parachute involved on a skydive. Would you be surprised to know that there are two?

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To non- (and new) skydivers, the use of (and differences between) the two parachutes might be something of a mystery. We’ve put this quick FAQ together to help you understand how the two residents of a magical backpack work together to deliver the safest, most-fun skydiving experience you can have.

1. Where Are Those Parachutes Located?

On a normal skydive, which follows USPA guidelines and FAA regulations for gear, each skydiving container (backpack-style harness) holds two parachutes. In fact, we refer to the combination as a “two-parachute system,” which sets it apart from the single-parachute systems used by BASE jumpers. (We’ll get to that later.) The “main parachute,” which the skydiver deploys on every normal skydive, sits in the bottom part of the container. The reserve parachute–which is only deployed in the event of an emergency–sits above it, over the skydiver’s shoulder blades.

2. How Often Is It Necessary To Use A Reserve Parachute?

It’s rare, these days, that a skydiver sees his/her reserve parachute. Skydiving malfunctions, even in cases where the skydiver makes dozens of jumps every week, are generally pretty rare. After all, skydiving technology has advanced to the point where parachutes deploy well, inflate efficiently, and have a much reduced likelihood of entanglements or compromising damage inflicted during the opening process. Modern skydivers are very lucky, in that regard; jumpers in the earlier years of the sport had to manage ugly malfunctions with startling regularity.

3. How Is A Reserve Parachute Used?

In both sport (solo) and tandem skydiving, the deployment of a reserve is pretty much the same. In the event of a malfunction, the responsible skydiver determines that his/her main parachute is unlandable. Upon that determination, he/she uses a handle on the skydiving rig to detach (“cut away”) the malfunctioning main. The cut-away main then comes free of the system and sails off into the sky for later retrieval. The skydiver then uses the handle on the other side to deploy the reserve parachute.

4. How Is The Reserve Parachute Different From The Main?

The main is “a nine-celled ram-air canopy,” which means that it is an airfoil designed in nine segments and built to fly with agility, glide far and deliver a fun in-flight experience for the passenger. A reserve is built with the emphasis on one aspect of its performance: a fast, stable, on-heading opening, with the understanding that the canopy pilot’s single concern is getting a good parachute overhead for a safe landing. Reserve parachutes do this job very, very well.

5. How Does The Instructor Know When The Main Parachute Is Unlandable?

Competent, licensed, professional instructors–as all of our instructors are, here at Skydive Long Island–are thoroughly trained in the use of reserve parachutes. Your instructor has definitely deployed a reserve, has definitely landed a reserve and is the living proof that reserve parachutes work. If you have questions about the experience, ask! You’ll get a thorough (and exciting!) answer, for sure.

Do you have additional questions about how skydiving works? View our Frequently Asked Questions page where we answer top queries on skydiving or check out one of our most popular articles: How Dangerous is Tandem Skydiving.

Do Parachutes Go Up When Opened?

Skydiving Parachutes Are Designed to Descend

Once skydivers have fallen to 2,500 ft, they usually deploy their parachutes and we have all watched videos where it looks like the skydiver goes up during the deployment process. But is this actually true, do parachutes go up when opened?

Skydivers do not go up during the opening process of their parachutes. Although opening the parachute feels like an upward acceleration, skydivers still move in a downward direction towards the earth. That being said, there are ways how skydivers can move upward with their parachutes.

In addition, I have summarized my three most favorite sports in which you can go up with a parachute.

Why Parachutes Do Not Go up During the Opening Process

In order to understand why parachutes do not go up upon deployment let us take a closer look at the opening process:

  • Skydivers should deploy their parachute at 2,500 ft in a belly-to-earth position. Depending on his weight and flying position, the skydiver will have a speed of 100 to 120 mph.
  • Once the skydiver deploys the parachute (by pulling the parachute ripcord), the pilot chute starts catching air and inflates. The pilot chute stabilizes the skydiver and helps him to stay in the right position.
  • If the skydiver is unable to pull the ripcord, the Automatic Activation Device (AAD) will open his parachute at a preset altitude.
  • The pilot chute starts slowing the skydiver down and pulls the canopy out of its bag. Once the canopy leaves its bag, it starts inflating and decelerates the skydiver even more.
  • When the canopy is fully open, the speed of the skydiver will be reduced to 17 mp/h (28 km/h).

Once the canopy is open and has reduced the falling speed of the skydiver, he can start steering it and navigate to the dropzone. Skydiving canopies are designed in such a way that they allow for a slow and comfortable height descent and not for an ascent.

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In order for the parachute to go up, the skydiver would either need to steer the parachute in areas of ascending air that will lift him up or create so much speed and air buoyancy that allow him to move upward in a diagonal direction.

The first approach is possible if the skydiver jumps in certain weather conditions. The second approach is impossible because every part of the parachute is designed for speed deceleration and safety maximization.

Why It Feels Like Going up When Opening the Parachute

Nonetheless, the sudden speed reduction from 120 mph to 17 mph can feel like an upward move for the skydiver. This is mostly due to the deceptive feeling of free fall and visual illusion.

Skydivers reach terminal velocity during their freefall when the air resistance is as strong as the gravitational pull from the earth. This air resistance does not only keep skydivers at a constant speed but moreover feels like an air cushion, that stabilizes one in the air. Once terminal velocity is reached, it does not feel like falling anymore, rather like floating in the air.

The opening maneuver of the parachute only takes three seconds from activating the opening mechanism to fully inflating the parachute. During the inflation process, the skydiver will be decelerated at a fast rate. More specifically, the skydiver feels a strong tug from the harness around his shoulders.

Because it feels like floating beforehand, the tug and sudden speed deceleration can feel like being pulled upward. This impact is even increased because your eyes do not have any fixed points for reference besides other skydivers.

However, if your eyes use other skydivers as fixed points they will be deceived by a visual illusion – specifically when the other skydivers fall at a similar speed. If you fall together at a similar speed, it looks like you are not moving. This is intensified because the objects on earth are so far away and seem so small that it does not look like moving towards them.

When the skydiver deploys his parachute before the other skydivers, they will continue to fall. As they used to be the fixed points, it does not look like they are falling but that you are lifted upwards.

It is quite comparable to a train ride. If you are on a train and do not look outside the window, it looks like nothing is moving. However, they are moving – only at the same speed. If you were now to be decelerated suddenly, it would also look like you go backward.

Why It Looks Like Skydivers Go up When Opening Their Parachute

The effect is quite similar in skydiving videos and movies. The skydiver deploys his parachute first and will start to decelerate while the videographer is still falling down at a faster speed. The videographer will then turn around towards the skydiver and the angle of the shot is now upward which creates an illusion that the diver is moving up because of the opened parachute.

If you want to know more about this effect, you should watch sky surfing videos on YouTube. In addition, to the normal skydiving harness, skysurfers are equipped with a surfboard. The surfboard helps them move around and it really looks like they would surf in the air.

How Skydivers Can Go up With Their Parachutes

As mentioned earlier, it is possible for skydivers to go up with their parachutes if they jump in the right (and dangerous) weather conditions.

During thunderstorms, high winds, and dust devils skydivers encounter very strong and erratic winds that are strong enough to push the parachute to fly backward. This backward lift can push the skydiver up to extreme and dangerous heights which is extremely unsafe.

Being lifted to extreme heights can be dangerous, divers might be blown off course from the drop zone or the parachute might collapse due to the strong force of the wind. In some cases, jumpers can be seriously injured or even result in fatalities if they land on unsafe areas with power lines, trees, infrastructure or near bodies of water.

Due to these risks, it can also be extremely dangerous to deploy the parachute too early at a high altitude. If you want to know more about the three underestimated risks of early parachute deployment, check this article.

For example, on the 21st of April 2019, Sgt. 1st Class Justin Goff from the US Army died due to a parachuting accident in North Carolina. As per the Police investigation, he was able to deploy his parachute but he ran into high winds which caused him to plummet towards the ground.

As a result, it’s not advisable to jump during inclement weather especially if the winds are more than 30 mph (26 knots). The recommended wind limit for student jumpers is around 18 mph (15 knots) while licensed holders can jump with winds between 20-29 mph (17-20 knots).

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Skydivers can also be lifted up by strong winds on the ground. In order to avoid such unplanned take-offs and being dragged around at the dropzone, it is advisable the skydivers fold their canopy immediately after landing.

Sports in Which You Can Go up With a Parachute

As discussed, skydiving parachutes are only used for descending purposes after jumping from an aircraft or other high places. However, small changes to the parachute can allow it to move upward. Here are three examples of aerial sports that allow athletes to move from the ground up.

Parasailing, also known as parakiting or parascending, is a recreational sport wherein you will use a specially designed canopy called parasail while being towed behind a vehicle (usually a motorboat or a truck). The parasailor has zero or no steering control over the parachute since it is attached to the moving vehicle.

You just need to lean back and enjoy the parachute ride while 500 feet above sea level. The parasail canopies also come in different colors and designs since it is usually being offered to tourists on vacation.

Paragliding on the other hand, is also a recreational aerial sport that uses a free-flying, lightweight foot-launched aircraft called paraglider. To launch a paraglider, you can either do a forward launch by running down a slope or reverse launch wherein the pilot is facing the wind then bringing it to a flying position by turning around and running under the wing. The paraglider sits in a harness suspended below a parachute which will allow them to fly for many hours, gain height and cover long distances.

Paramotoring, also known as Powered Paragliding (PPG), uses the same principle of paragliding but way faster since it is powered by a paramotor (which includes an engine, fuel tank and propeller). A powered paraglider can go as fast as 15 to 50 mph (24 to 80 km/h) and can reach an altitude of about 18,000ft or more depending on the engine used. The use of powered paragliders varies from personal or recreational use.

Highest Altitude Reached by an Ascending Parachute

On 23rd July 2016, a French paraglider Antoine Girard ascended from 16,404ft (5,000m) and set the World Record of the highest altitude of a voluntary ascent by a paraglider pilot. He reached the height of 26,762 ft (8,157 m) while flying over the summit of Broad Peak. The Broad Peak is the twelfth highest peak in the world and located between the border of China and Pakistan.

The entire flight took 7 hours and covered 120 km before safely landing near Skardu City in Pakistan. It also took Antoine Girard a year of planning and preparation. It was also originally planned to be a team expedition rather than a solo adventure. His expedition partner canceled five days before the planned start – which did not stop Girard from completing the project and becoming the world’s record holder for the highest paragliding altitude.

In conclusion, no matter which aerial sport you choose, the main purpose of the parachute is to safely land the wearer to the ground from any given altitude. A skydiver can practice different canopy exercises to help them be prepared for any situation that might arise during the free fall.

Having said that, enjoy your freefall!

Hi, I’m Kai. The first time I jumped out of an airplane and experienced free fall was one of the most amazing moments of my life. For me, skydiving does not only stand for freedom and independence but being present in the moment and being respectful to others and oneself. Now I want to share what I’ve learned with you.

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ABOUT ME

Hi, I’m Kai. The first time I jumped out of an airplane and experienced free fall was one of the most amazing moments of my life. For me, skydiving does not only stand for freedom and independence but being present in the moment and being respectful to others and oneself. Now I want to share what I’ve learned with you.

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