Professor Julien Peelman breaks down the glide ratio numbers for JYRO canopies, why high-performance wings often have lower glide ratios on full drive, and why canopy performance is a lot more complicated than it first appears.
This is Lesson 4 in our Aerodynamics for Dummies series: breaking down lift, drag, glide ratio, canopy performance, and the science behind modern parachute flight.
Ep. 1: Lift
Ep. 2: Drag
Ep. 3: Glide Ratio
Ep. 4: More Glide Ratio
Lesson 4 Key Points
- JYRO Canopy Glide Ratios
- Why High-Performance Canopies Have Lower Glide Ratios
- How Canopy Trim Affects Glide Ratio
- Pilot Drag and Canopy Size
- What Glide Ratio Means in the Real World
- How Wind Affects Glide Ratio
- Still Curious? Let’s Get Nerdier
A canopy’s glide ratio doesn’t just depend on the wing – it depends on trim, speed, pilot drag, and the winds trying to ruin your day.
JYRO Canopies Glide Ratio
Here are the GR numbers for our JYRO canopies on full drive (within +/-0.3):
- Tandem: 3.0
- Student: 3.2
- Safire 3: 2.8
- Crossfire 3: 2.8
- JFX 2: 2.3
- Leia: 2.1
- Petra: 1.8
Why High-Performance Canopies Have Lower Glide Ratios
As you can see, our high performance canopies have a lower GR on full drive than our more docile range. So why is that? They’re supposed to be more sophisticated, right?! Well, it’s mainly for a couple of reasons.
How Canopy Trim Affects Glide Ratio
The trim is designed differently.
As opposed to paragliders, our wings are not trimmed to fly at their best Glide Ratio. They are trimmed steeper to provide a nice dive and a wide range of speed. This allows for fast flight and soft flare. Exactly what you want from a skydive parachute.
For instance, if you put your Petra on deep brakes, you can fly next to a Student canopy. If you let Petra out on full drive, you can follow a wingsuit. Take it one step further and in a sustained turn, you could follow someone in freefall!
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- Petra flying with Kraken. Photo credit: Logan Donovan
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- Petra, XRW and wingovers. Photo credit: adventuroys
Pilot Drag and Canopy Size
Canopy size and Pilot Drag also factors into determining the Glide Ratio.
All the tests done to record this data, were done with a wing loading (WL) within the recommended range for each canopy. So the most advanced wings have been tested with small sizes (typically a 69 for Petra). While the beginner canopies have been tested on bigger sizes (typically a 139 for a Safire 3). Since the pilot doesn’t scale down, their Drag has a much greater impact on the small canopies than the big ones.
In conclusion, we design more sophisticated wings, not for Glide Ratio, but for a wider speed range. A flat trimmed Petra 139 would certainly out-glide a Safire 3 139, but a Safire 3 69 would be impossible to land!
What Glide Ratio Means in the Real World
So what does that actually mean in the real world?
Another aspect to consider is if you are coming from a long spot. There is not much margin to improve the Student Glide Ratio by the way it is designed. However, for your Leia, changing body position (e.g. leaning back in a Mutant Harness) or using rear risers, you can gain a lot and probably get close to 3.0.
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- Cornelia using her Mutant harness and Petra. Photo credit: Mordace Blq
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- Harness position and body input can dramatically affect glide efficiency and canopy performance. Photo: Mordace Blq
How Wind Affects Glide Ratio
Finally, in the real world, Glide ratio depends heavily on winds. Flying upwind will significantly decrease your Glide Ratio. Anyone landed off because you were dropped downwind? That’s why. On the flip-side, you can cover miles and miles with the right tail winds. Unfortunately, it’s not quite as simple as this, though. To complicate things further, winds have more impact on slower canopies than fast ones.
For example, say your Safire 3 is flying at an airspeed of 50 km/hr facing winds of similar velocity. It will have a GR of 0.0 and will fly straight down. Whilst your mate is flying their Leia at 100 km/hr in the same winds, will still have a ground speed of 50km/hr, giving it a GR around 1.0. So that’s why when you and your mate exit the plane at the same time, you land off, but they arrive back to the PLA.
Basically, knowing your canopy is good, but you also need to know the winds!
Understanding glide ratio in real conditions helps canopy pilots make smarter decisions during long spots, crosswind returns, and high-performance landings. Modern parachute aerodynamics are about more than just wing design — pilot input, speed, body position, and wind conditions all affect canopy efficiency.
To understand all of this better, we would need to introduce the concept of Polar curves. But that’s for another episode…
Speaking of next episodes, we’ll be talking about how to manipulate Drag to your advantage. Think Cornelia Mihai zooming through the Speed course. Or Jason Sanders powering passed the final markers on a Distance round.
Still Curious? Let’s Get Nerdier
Aerodynamics for Dummies: Glide Ratio
Research & Development: Tales from the JYRO Test Jumpers
JYRO Test Pilots: An Introduction
25 Ways to Become a Better Canopy Pilot
Canopy Flight vs Canopy Ride