A round parachute may look simple when it is packed, but the process that turns that packed canopy into a pressurized, functional parachute is anything but simple.
Understanding inflation starts with understanding one basic principle: a round canopy needs air to enter the canopy and create pressure inside it. That internal pressure gives the canopy its shape and allows it to produce the drag necessary to slow the jumper’s descent.
Unlike a ram-air canopy, a traditional round canopy does not become pressurized through individual cells. Air enters primarily through the opening around the skirt of the canopy.
During deployment, the canopy begins to move away from the jumper and the fabric starts to catch the surrounding airflow. As the skirt opens, air is able to enter the canopy and begin building pressure.
The relationship between the skirt, the canopy fabric, the suspension lines and the airflow determines how the canopy develops its shape during inflation.
A round canopy does not simply go from packed to fully inflated in one instant.
There is a sequence of events.
The deployment system first extracts the canopy from the container. The canopy then begins to spread and the suspension lines reach their extended position. As the canopy encounters airflow, the fabric begins to take shape and the skirt starts allowing air into the canopy.
As air continues to enter, the canopy expands and becomes increasingly pressurized. Eventually, the round canopy reaches a stable inflated shape capable of producing its intended drag.
This process can involve noticeable changes in canopy shape as the fabric responds to the airflow.
Inflation depends heavily on the airflow surrounding the canopy.
A canopy needs sufficient airflow to develop pressure, but the inflation process is not simply a matter of “more air equals better inflation.” The way the canopy interacts with the airflow is a dynamic process involving the fabric, suspension lines and the changing shape of the canopy.
As the canopy inflates, the airflow around it also changes. The canopy can temporarily deform, expand and settle as it reaches a more stable configuration.
Research into parachute inflation has documented this changing behavior, including repeated expansion and contraction effects sometimes described as a “breathing” motion during the inflation of round parachutes.
For a BASE jumper, understanding parachute behavior is not simply academic.
Every part of a parachute system has a purpose, and understanding how the canopy behaves during deployment helps build a better understanding of the system as a whole.
The goal is not to memorize a sequence of events. The goal is to understand what the equipment is doing, why it is doing it, and how different parts of the system interact during deployment.
That understanding becomes particularly important when considering low-altitude environments, where there is very little time available for a deployment to develop.
Think of a round canopy as a flexible structure that needs airflow to become pressurized.
The deployment process creates the opportunity for the canopy to spread.
The skirt provides the primary entrance for air.
Air entering the canopy creates internal pressure.
That pressure gives the canopy its inflated shape.
The inflated canopy produces drag.
That drag slows the jumper’s descent.
Each stage depends on the previous one, which is why understanding inflation is an important part of understanding parachute deployment.
A round parachute may appear straightforward from the ground, but its inflation is a constantly changing interaction between fabric, airflow, pressure and movement.
The more you understand what happens between the moment the canopy leaves the container and the moment it reaches its inflated configuration, the better you can understand the parachute system you are relying on.
Knowledge of your equipment is part of being prepared.
Founded in 1996 at the Perrine Bridge in Twin Falls, Idaho, Johnny Utah® established the longest running BASE First Jump Course on the planet. Under his expert guidance, three generations of students have safely made their first BASE jumps from the iconic 486-foot Perrine Bridge.
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