Canopy Durability

[Airviking 0]

I'm just getting back into the sport after a 22-year layoff, and I'm shopping around for some used gear. It seems that canopies are much more durable now than back in the '80s. IIRC, 800-1000 jumps on a main (like my Pegasus), and it was toast. Now, it seems that mains can go 1,500 jumps no problem, provided you maintain them.

1) Do I have my facts right?
2) If yes, is this due to softer openings, ZP fabric, or what?

I believe you have my stapler.

[davelepka 4]

It's the fabirc. F-111 fabric was strong and durable after 1000 jumps, but the porosity went up so much that the canopy didn't perform as needed anymore.

Z-po fabirc is good stuff, but not perfect. Higher time canopies can run into fabric strength problems, and some of this has to do with location. Canopies jumped in the dry, dusty southwest or sandy areas will have a shorter lifespan than one jumped in a dust/sand free environment.

As usual, have all used equipment inspected by a rigger. Things like containers and reserves are typically airworthy or not, so those are easy calls to make. Mains are another story as an airworthy main may have little life left in it or the lines. It may hold together, and survive an opening, but the flare performance or state of trim may be less than desireable. Once a canopy has been deemed airworty, the condition of the fabric and lines becomes a seperate evaluation to determine the market value.

Edit to add - a canopy with good fabric and worn lines is not a bad thing. Provided that the price is such that it accounts for a reline (about $250) then you end up with a canopy where you know the exact number of jumps on the lines, and not just a 'guesstimate' by the previous owner. A fresh line set will typically result in better openings and flare performacne.

[Beatnik 2]

If you want to get technical, F-111 is actually a stronger material than ZP is. This is due to the process that impregnates silicon into the ZP material. The ZP doesn't increase in porosity which why the canopies are lasting longer. A ZP canopy is maintaining its flight characteristics longer than an F-111. So regular maintenance (e.g. relining) will allow for a longer life with a ZP canopy compared to F-111.

Softer openings with newer canopies are due to the way they are being designed not much to do with the material itself. Your information was along the right tracks.

[Airviking 0]

Thanks all,

So, if I understand correctly, F-111 canopies get used up quicker, not because F-111 is less structurally durable than ZP, rather because they increase in porosity at a higher rate than ZP.

What then signals the end of life for a well-maintained ZP canopy? Is it porosity for ZP as well, just further out in time?

I believe you have my stapler.

[pchapman 279]

An old canopy will get easier to pack - so porosity or permeability, whatever you want to say, does go up. I don't know what the contribution is from the fabric itself vs. sewn seams, but if the canopy gets easier to stuff in the bag, then something is letting more air through.

An old canopy may start to show a bunch of pinholes in high wear areas like the top center panel at the back, or eventually just rip. (e.g, as for a 3200 jump Stiletto a friend used to jump.)

Occasionally someone might pull test their canopy, if they'd rather get a rip on the ground than in the air.
(Eg, the center aft panel on an old Stiletto ripped at 20 lbs when I tested it. It could have kept flying. How long? Who knows, but probably quite a while longer.)

Performance will go down a little with age. Although the drop will be less sudden and smaller than for F-111, one then has to decide whether the missing performance was really needed or if one can get away with a little less.

Often a canopy is retired when someone figures they're rather put their money towards a newer canopy, rather than paying for a reline on the old canopy. So you might have a canopy lying around that is basically free to anyone who wants to pay for a reline.

Others will have better info on canopy lifetimes. If one is around a bunch of professionals putting 500+ jumps on a canopy a year, they'll learn more about this than when being around fun jumpers putting 100 jumps a year on a canopy.

[billvon 3,078]

>What then signals the end of life for a well-maintained ZP canopy?

For Amy and I, the indication that the canopy is nearing the end of its life is when the center cell blows out. Generally we get about 1500-2000 jumps out of a canopy with 4-5 line changes along the way.

[DrewEckhardt 0]

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An old canopy will get easier to pack - so porosity or permeability, whatever you want to say, does go up. I don't know what the contribution is from the fabric itself vs. sewn seams, but if the canopy gets easier to stuff in the bag, then something is letting more air through.

Sine you still can't blow through the fabric I assume it's the stitching holes opening up.

[TomSpoon 4]

The ZP canopies of today have a much longer useful life than the F111 canopies you remember.

I have seen ZP canopies with over 6000 documented jumps that PD still considered airworthy.

My Spectre 170 has over 2000 jumps on it, is on it's third line set and still flies and flares very well.

Exposure to Dirt, UV and packer sweat probably have a greater effect on canopy life than the number of jumps.

[Beatnik 2]

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Exposure to Dirt, UV and packer sweat probably have a greater effect on canopy life than the number of jumps.

Sweat seems to be a large factor with canopies. A friend of mine in Brazil says that centre cells are worn out quickly there and they suspect it is because it is hot and a lot of people pack without shirts on.

[TomSpoon 4]

A component of sweat is salt. Salt crystals deteriorate nylon.

Billvon mentioned that he retires his canopies when the center cell blows out. The top of the center cell is most exposed to sweat.

I had the top center skin of my spectre replaced at about 1800 jumps. Cost about $150 at PD.

[fcajump 164]

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Billvon mentioned that he retires his canopies when the center cell blows out. The top of the center cell is most exposed to sweat.

Yea... when you have to replace the PC and D-bag because they handed with 1/2 your center cell, it might be time to replace from risers up...

Always remember that some clouds are harder than others...