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So I thought my sabre2 170 was starting need a reline...

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Noticed that my sabre2 wasn't flying as well as it used to... So I packed her up and sent it down to PD... Based on the stats I knew it was ready for a reline, but never got around to measuring...

A-lines measured:
A5: short 6"
A4: short 3 1/2"
A3: short 2"
A2: short 1 1/4"
A1: short 7/8"

Now I haven't done a lot with line trim, but 6" of shrinkage on the outer A lines? Does that strike anyone as a LOT or is it just par for the course? I think there are about 450-500 on that...

-Michael

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Now I haven't done a lot with line trim, but 6" of shrinkage on the outer A lines? Does that strike anyone as a LOT or is it just par for the course? I think there are about 450-500 on that...



That is about right.

This is why I think Spectra is the worst line medium out there today!

BS,
MEL
Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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I think it was riggerrob who said spectra can be out of trim at 200 jumps. I would go for vectran or hma on any canopy except if you want to guard against a hard opening (ie camera) then perhaps dacron.

edit - don't ever get 550 spectra like I did many years ago.

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This is why I think Spectra is the worst line medium out there today!



Even for people that pack their rig outdoors (under an open sky/sun) with lines more exposed to UV ?

cheers



Disclaimer - I am not a rigger.

That said, I think I'd be more worried about UV exposure to the CANOPY than the lines...
Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

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Disclaimer - I am not a rigger.
That said, I think I'd be more worried about UV exposure to the CANOPY than the lines...



Yep - that too... ;)
But I'm actually wondering how much vectran lines are susceptible to uv rays. How much do they shorten lines lifetime, and if such kind of weakening show up somehow on the lines ?

cheers ;)

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Spectra is actually not that UV sensitive compared to nylon. For my canopy the lines will depreciate about $0.60 per jump. Dacron is not available, just the 2 sizes of spectra. I went with the larger of the two.

I was wondering how badly out of trim those measurements show? The canopy flew very poorly. I may be a rigger but I lack the experience to judge how badly out of trim it was. Old guys with grey hair? Opinions?

-Michael

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Now I haven't done a lot with line trim, but 6" of shrinkage on the outer A lines? Does that strike anyone as a LOT or is it just par for the course? I think there are about 450-500 on that...

-Michael



Normal. My Stiletto 120 (short lines) lost about 6" on the outer lines at 600 jumps and opened wonkier before then.

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so when you lay the canopy out, flat pack style, wouldnt it be easy to see 6" of differential? tony



That would actually be good come-uppins for me since I've helped the old guys with their pro packing a few times I should have gotten one of them to help me with my flat packing...

-Michael

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so when you lay the canopy out, flat pack style, wouldnt it be easy to see 6" of differential? tony



Maybe, but what are you comparing it to?:)
Shrink on a Spectra lined canopy usually happens more or less symmetrically, and unless you have a base line to measure from (the original measurements) it can be hard to tell how much has occurred. Not all the "A" lines are the same length to begin with for example.
----------------------------------------------
You're not as good as you think you are. Seriously.

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Spectra is actually not that UV sensitive compared to nylon. For my canopy the lines will depreciate about $0.60 per jump. Dacron is not available, just the 2 sizes of spectra. I went with the larger of the two



If you need Dacron, we install them. It sure cuts down on those rogue Sabre2 openings......


600lb Technora even works better in some cases!

BS,
MEL
Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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I might be interested on that after I put about 400 jumps on the new lineset. I assume you actually make the sets and install them?

I've been able to tweak the packing so this sabre2 opens beautifully and softly every time... so far. Let's not talk about on-heading openings though!

-Michael

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so when you lay the canopy out, flat pack style, wouldnt it be easy to see 6" of differential? tony



Maybe, but what are you comparing it to?:)
Shrink on a Spectra lined canopy usually happens more or less symmetrically, and unless you have a base line to measure from (the original measurements) it can be hard to tell how much has occurred. Not all the "A" lines are the same length to begin with for example.


The 6" differential should be apparent in a pro-pack as well.

On most canopies, the "A" lines start out within an inch or so of the same length. When they do not start out exactly the same length, the outboard lines are longer.

If all the lines shrink (or elongate) at the same amount, there is not a problem -- but Spectra line sets shrink fastest at the corners, the outboard "A" lines and the brake lines. It is the differential shrink that's the problem, so a quick method of checking trim is to compare the outboard "A" line with the inboard "A" line on the same link.

Mark

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Dacron is not available, just the 2 sizes of spectra.



That's incorrect... PD will put a Dacron line set on that canopy, I know, I had them put a set on my Sabre 2 210.

It's less expensive than Spectra too... :P

"If all you ever do is all you ever did, then all you'll ever get is all you ever got."

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That's about what my Spectre was like after about 500 jumps. Maybe it's because the change in trim is gradual, but I didn't notice it when packing. The openings and flare begin to get worse, so I measured it and sure enough... I had it relined with Dacron.
You don't have to outrun the bear.

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That's incorrect... PD will put a Dacron line set on that canopy, I know, I had them put a set on my Sabre 2 210.:P



All I can do is ask again and get 100% clarification. I was told that the only 2 linesets available were the two I listed. Maybe they just assumed I wouldn't be interested in dacron. I don't remember the disadvantages of dacron so I'll have to open poynter when I get home to see if I actually want it.

-Michael

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Dacron has one main disadvantage - the lines are thicker. That shows up as greater pack volume and greater air resistance. The pack volume is probably not a show-stopper for most people, but for swoopers on small canopies, the significantly greater air resistance is. Let the debate begin!
You don't have to outrun the bear.

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Did you compare each line length with the PD chart. 6" seems a lot. You will really know if your canopy was out of trim when you will fly it with a new set of lines. A lot of people who did it say their canopy with a new set of lines was flying differently (like a new one). I hope you will still like it that way. You should keep the lines like the original ie. Spectra 825.
Learn from others mistakes, you will never live long enough to make them all.

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