Canopy Downsizing Chart by Brian Germain

[BrianSGermain 1]

Many folks believe that we need better guidelines for canopy downsizing. I have spent a great deal of time putting together a chart for exactly that purpose, along with 21 pages of ideas that make sense of the chart.

Here is the link:

http://www.bigairsportz.com/pdf/bas-sizingchart.pdf

Instructional Videos:www.AdventureWisdom.com
Keynote Speaking:www.TranscendingFEAR.com
Canopies and Courses:www.BIGAIRSPORTZ.com

[frost 1]

Thank you! This should be a locked sticky for all future new jumpers.

[ianmdrennan 2]

Suggestion noted

Performance Designs Factory Team

[rmarshall234 14]

AWESOME!

I haven't digested it all yet but what a nice piece of work. Also, kudos for having the guts to do what needs to be done. Thank you.

[BrianSGermain 1]

If you look at the numbers carefully, you will see that the wingloading recommendations are not linear. Smaller canopies match you with a somewhat lighter loading, while big ones suggest a heavier load, to reflect the non-linear nature of scale effects.

Instructional Videos:www.AdventureWisdom.com
Keynote Speaking:www.TranscendingFEAR.com
Canopies and Courses:www.BIGAIRSPORTZ.com

[dragon2 2]

This should also be a sticky: Downsizing Checklist By Bill von Novak

ciel bleu,
Saskia

[Cornholio 0]

Sweet!! According to the chart at exit wt 235 (don't laugh) and 500+ jumps, I should be jumping between a 150 and 139.

Kidding aside, I'm very happy with my 190 and have no plans to downsize anytime soon. However, much thanks Brian for putting that together. That should help a lot in helping the young (and stupid) from jumping a canopy that's too small for them.

Butthead: Whoa! Burritos for breakfast!
Beavis: Yeah! Yeah! Cool!
bellyflier on the dz.com hybrid record jump

[GLIDEANGLE 1]

I think you misunderstand the chart. The chart is describing the MINIMUM canopy size.

Note the following direct quote from the chart:

*Jumpers are welcome to use a larger parachute than the chart suggests.

The choices we make have consequences, for us & for others!

[Hausse 0]

Gllideangle, I think you misunderstand irony

[jf951 1]

HOLY HELPFUL!!!!
ur awesome!!!

Jump more, Bitch less.

[EXTremeWade 0]

Awesome..I really am impressed. Brain, do you have a degree in AE?

wade

[regulator 0]

It looks like my canopy choice was correct according to Mr. Germain. I currently have 35 jumps with my Sabre2 190 and I weigh 155 lbs. I guess I payed attention after all!

[anycz100 0]

I just tried to stall my 168 Pilot loaded at 1.17. I pulled the brakes all the way down and held it for good 10s. It did not collapse or anything like that. It was square, stable and slow. I already shortened the brakes cause it had no flare. Is it normal? Are the brakes still too long?

[phoenixlpr 0]

Quote

I pulled the brakes all the way down and held it for good 10s. It did not collapse or anything like that. It was square, stable and slow. I already shortened the brakes cause it had no flare. Is it normal? Are the brakes still too long?

What is the connection? How would anyone able to tell if they are long or not from this info you provided?

[BrianSGermain 1]

Canopies over 150 square feet often run into this conundrum. Either you can stall it or you can front riser it, but not both. It is generally less costly to be unable to stall a large wing, since the slow flight prior to the stall is sufficiently slow to allow for good landings. If you tighten the brakes too much in order to reach the stall, you will sacriice the ability to front riser effectively and may be in brakes when you arms are all the way up. It is possible that the optimum configuration for this canopy is right where you are, or even slightly
longer.

Instructional Videos:www.AdventureWisdom.com
Keynote Speaking:www.TranscendingFEAR.com
Canopies and Courses:www.BIGAIRSPORTZ.com

[anycz100 0]

Thanks Brian, my instructor told me a similar thing. I was looking for a second opinion.

[linebckr83 3]

My Pilot 188 was the same way. I had to take a wrap to stall it out on toggles. Like Brian said, the stall speed on those bigger canopies is low enough that the speed you can slow down to with the toggle stroke is more than enough to flare correctly.

"Are you coming to the party?
Oh I'm coming, but I won't be there!"
Flying Hellfish #828
Dudist #52

[bluetwo 0]

Saved the chart to my desktop so I can check it out more later. Can't say I understand all the info there (below the chart that is), but it should be interesting to figure out.

Thanks

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[Scubadivemaster 3]

Nicely presented.

I just had a very heads-up newer jumper ask me to explain to his 150 jump, 88lb girlfriend that she would be fine jumping a Nitro 108 because her geared up wingloading was only .98 to 1. He was surprised when I told him absolutely not. He was operating on the limited information that is readily available that wingloading is the most important (or only) consideration. We are failing new jumpers by giving them incomplete information.

The "Non-linear Nature of Parachute Performance" should be required reading for every new jumper and anyone who advises jumpers on the canopy they should fly.

[bluetwo 0]

Help please. I did a search for the Non-linear Nature of Parachute Performance but all I got was this thread...

Can somebody point me to it please?

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[Scubadivemaster 3]

The link in the original post. Its a few pages down.

[Blink 1]

Quote

Help please. I did a search for the Non-linear Nature of Parachute Performance but all I got was this thread...

Can somebody point me to it please?

http://www.bigairsportz.com/pdf/bas-sizingchart.pdf
Page 4.

[pchapman 279]

Quote

Quote

Can somebody point me to it please?

http://www.bigairsportz.com/pdf/bas-sizingchart.pdf
Page 4.

That seems to touch on the subject but nothing more. (But I just skimmed it.) I believe it was Performance Designs / John Leblanc who have the full article on wing loading vs. overall weight. Must be at PD's web site.

[bluetwo 0]

Holy crap, I got three people helping me?

That's cool though. Thanks for recommending students read that. It does seem like a lot at first but surely it's good to know.

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[castrodavidd 0]

BG,
I have 125 jumps and fly a Heatwave 190 loaded at 1.4. I have been working on 90 degree landings and carving. I have read your book, down sizing chart, and Novack's checklist. I am wondering at what point can a jumper disregard the jump numbers for down sizing and use the ability of the pilot. I would like to get a recomendation from you for a canopy coach in the midwest " Oklahoma Area" that could evaluate me on my ability and not the jump numbers. I would like someones honest opinion weather I could be safe on a smaller canopy.

Also, I was reading about the non-linear nature of scale effect. Your book says that aerodynamics don't scale, and I can't understand why they wouldn't. Having taught aerodynamics for airplanes and helicopters I thought I knew this subject pretty well. Airplane manufactures in the past used scale models to determine stall speeds, stability characteristics, and drag ratios prior to ever building a prototype. If it works on a rigid airfoil how does that differfrom a nonrigid canopy? Are there any theoretical differences between a canoy and an airplane wing?