Foundations of Flight | Ram-Air Parachute Anatomy—Cells

Brought to you by Niklas Daniel and Brianne Thompson of AXIS Flight School at Skydive Arizona in Eloy. Images by Bruce Fournier.

In the photo above, the area that makes up the canopy’s center cell is highlighted in red.

It is important for jumpers to have at least a rough understanding of the different areas and features of their ram-air parachutes. Whether you are trying to describe a specific part that needs maintenance to a rigger or you are discussing your last landing with a canopy coach, a common language and terminology can help avoid confusion. The following provides a look at the internal components of your parachute that are hidden from view.

Concept: Cross-Sectional Area

A cross section provides a two-dimensional view of an object as if it were cut in half, revealing details of its inner workings. This can help shed some light on very specific areas, although they will make up only a small piece of the puzzle. There are generally six vantage points from which to view a cross-sectional area. These are typically at right angles to the three axes:

Equipment: Cells (Longitudinal Axis View)

In the previous article we defined what a ram-air parachute is and how to check if it is working properly. Now we will take a closer look at what the air is being rammed into: the cells.

In simplest terms, a cell is the space that is occupied by air when a parachute is inflated. The word “cell” comes from Latin and means “small room.” In the case of a parachute, the ribs make up the walls, the bottom skin is the floor and the top skin is the ceiling. The nose (leading edge) of the parachute has openings that capture the relative wind, pressurizing the internal structure of the wing as the closed trailing edge traps it. We’ll cover more details about these features in the next issue.

A parachute can have any number of cells, but most common sport parachute designs have seven or nine. Most sport parachutes utilize a bi-cell design, meaning there are two rooms per cell. Therefore, each cell has three ribs, two which are called loaded ribs (because they have suspension lines attached to them) and one in the middle of the cell that is not loaded. The purpose of non-loaded ribs is to provide additional connection points between the top and bottom skin. This helps shape the parachute into a more efficient wing.

Information about AXIS’ coaching and instructional services is available at axisflightschool.com. The authors intend this article to be an educational guideline. It is not a substitute for professional instruction.

More educational skydiving content, as well as this free article, is available by downloading the AXIS Skydiving app on your smart device.

AXIS Skydiving App 

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AXIS YouTube Channel

Foundations of Flight | Ram-Air Parachute and Canopy Check

Brought to you by Niklas Daniel and Brianne Thompson of AXIS Flight School at Skydive Arizona in Eloy. Images by Bruce Fournier.

Welcome Back!

After taking a two-year break since the last Foundations of Flight installment, AXIS is excited to announce that it is back with a new focus and look. Past articles (available at axisflightschool.com and parachutist.com) covered a wide range of skills and disciplines, but the new series is focused on specific canopy-piloting concepts. Using illustrations from the AXIS Skydiving app, this column will discuss one aspect—such as construction, a physics concept, a procedure or a flying technique—of a specific piece of equipment. Think of this column as a supplement to professional canopy coaching and a conversation starter rather than a substitute for training.

Introduction

There is much more to a parachute than just a nylon wing and some strings. Each component—which includes the canopy pilot—contributes to the performance of the parachute. A skydiving parachute is first and foremost a lifesaving device that is intended to be deployed at freefall speeds. Therefore, their design and construction are in many ways limited by their primary function. The canopy ride is not a necessary evil that lets you jump again, but instead completes the skydiving experience with a skill set all jumpers share. Developing skill under a wing that is appropriate for your level of experience and currency is much more rewarding than rapidly downsizing or relying on gimmicks. If you are looking for higher performance, approach the progression as growing out of a wing rather than into one.

Equipment: Ram-Air Parachute

A ram-air parachute is a nonrigid-textile wing with an aerodynamic cell structure. Inflated by the relative wind, a parachute requires constant pressurization to produce an airfoil shape. This is accomplished by using the airflow created as a parachute moves through the air, which gives it the name “ram-air.” Most commonly made out of a ripstop nylon, ram-air parachutes are flexible wings which are capable of much more complex behaviors than a ridged fixed wing found on an airplane. Ram-air parachutes have an arc-anhedral design (curved), which places the wing tips below the level of the center of the wing. The arched wing shape has spanwise (side-to-side) bumps, which are the result of the bulging of each cell as they are inflated with air.

Concept: Canopy Check

To determine whether you have a properly functioning main parachute, ask yourself these three questions after you have thrown the pilot chute:

1| There? Visually confirm that there is parachute fabric over your head.

2| Square? Determine if the shape of the wing is symmetrical.

3| Flare? Ensure you can steer and land the parachute using a controllability check. This entails making left and right turns, as well as a full flare (a simulated landing).

If the answer to any of the above questions is “no,” and you are unable to remedy the situation, proceed with emergency procedures at or above your decision altitude.

Information about AXIS’ coaching and instructional services is available at axisflightschool.comThe authors intend this article to be an educational guideline. It is not a substitute for professional instruction.


More educational skydiving content, as well as this free article, is available by downloading the AXIS Skydiving app on your smart device.

AXIS Skydiving App 

Google Play

Apple Store 

AXIS YouTube Channel

“Echoes in Time” Parachutist 75th Anniversary Center Fold

ECHOES IN TIME by Niklas Daniel | D-28906 | At Skydive Arizona in Eloy, David Robinson poses for a photo that reflects skydiving then and now.
Readers can see more of Daniel’s work at https://niklasdaniel.photography
Photos by Brianne Thompson.

View the digial version of Parachutist’s 75th Anniversary issue.

AXIS introduces new HFS dive pools

AXIS Flight School has introduced a new discipline – HFS (Horizontal Formation Skydiving), which is intended for indoor skydiving and utilizes both the belly and back-flying orientations simultaneously. It is therefore related to the horizontal rounds drawn during an MFS advanced event, but with an expanded dive pool in order to facilitate more rounds. These disciplines are a great stepping stone for those with formation skydiving experience and are wanting to explore free-flying. There are two versions to choose from: 2-way and 4-way. Both have been added to the AXIS DrawGenerator.

The 2-way HFS dive pool incorporates some elements from the USPA MFS and Collegiate dive pools, as well as the USIS 2-way VFS event. In addition there are some new formations created by AXIS to further expand the pool.

The 4-way HFS dive pool is an adaptation and was inspired by the 4-way VFS discipline.