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Tonto

Reserve lines

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Be aware that changing from spectra to dacron may be just enough to make your reserve too big for the container if it's a tight fit already. And some of the free bag line pouches these days aren't real big. It may be tough getting dacron lines in some pouches.

Why do you want dacron?
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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All the square reserves built during the 1980s had Dacron lines.
A few manufacturers built a few reserves with Kevlar lines, but Strong Enterprises is the only one who still does (Master 425 reserve). You have to be really careful to keep Kevlar lines away from hook Velcro or they WILL fray. Last year SEI replaced several lines on one of our reserves because of Velcro fraying. Parachutes de France seems to be the only manufacturer to use (Teflon) coated Kevlar lines.
Spectra is by far the most popular suspension line these days.
I wonder how much more experience manufacturers want on HMA, etc. lines before they start installing them on reserves.

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Doesn't Kevlar start to break down due to exposure to tempurature changes within 5 years of manufacturing?

Atleast I know that firefighters have a crapload of Kevlar in their gear and the kevlar is only rated to be safe for something like 5 years, then it has to be replaced.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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Doesn't Kevlar start to break down due to exposure to tempurature changes within 5 years of manufacturing?

Atleast I know that firefighters have a crapload of Kevlar in their gear and the kevlar is only rated to be safe for something like 5 years, then it has to be replaced.



that could very well be the extreme temperature changes that firefighters are more prone than most to be exposed to, yesno?

Do you know of a similar reglation for kevlar helmets vests, etc.. for military and police types?

Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time

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I'm not sure. There are quite a few law enforcement types and military types around on DZ.com that might be able to answer that question. My googling didn't turn anything up, I might try again tonight.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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Doesn't Kevlar start to break down due to exposure to tempurature changes within 5 years of manufacturing?

At least I know that firefighters have a crapload of Kevlar in their gear and the Kevlar is only rated to be safe for something like 5 years, then it has to be replaced.



>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Kevlar is highly resistant to high temperatures. Unlike most other synthetic fibers, Kevlar does not melt, it just "chars" at some high temperature. This charring characteristic makes it great for fire-resistant clothing for air crew and firefighters.
However, Kevlar has poor abrasion resistance, especially the uncoated fibers used in parachute suspension lines.
Kevlar is also rather brittle, in that it cracks after repeated flexing (i.e. stowing in rubber bands). Kevlar lines also did not stand up well to repeated hard openings. This is the main reason Kevlar did not survive as main suspension lines as (early 1980s) users started reporting broken lines after as few as 60 jumps!
Kevlar also deteriorates rapidly when exposed to sunlight.
I suspect that the 5-year life for firefighter's clothing made of Kevlar is more an effort to force the cheap skates in city hall to replace uniforms that have become faded, frayed and filthy from constant wear. Do you expect any piece of a uniform to still be functional after 5-years wear and tear?

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Do you expect any piece of a uniform to still be functional after 5-years wear and tear?



Nope, but I would hope that if the suspension lines of my reserve had kevlar in them or were kevlar, they'd hold up to 5 years worth of repacks and lets say (random number) two reserve rides.

Rob,

Once again, thank you for answering my question with a full explaination and some history. Its cool when you do that, since I tend to learn a lot that way.:)
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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Another possible reason for the 5-year stated lifespan of Firefighting equipment could be the same thing as the 5-year stated lifespan of motorcycle helmets: they may still work fine after 5 years, but there is the possibility of improvements in safety performance after 5 years.

Not sure how much I believe the "5 years" timeframe, though. :|

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However, Kevlar has poor abrasion resistance, especially the uncoated fibers used in parachute suspension lines.

Kevlar is also rather brittle, in that it cracks after repeated flexing (i.e. stowing in rubber bands).

Kevlar lines also did not stand up well to repeated hard openings. This is the main reason Kevlar did not survive as main suspension lines as (early 1980s) users started reporting broken lines after as few as 60 jumps!

Kevlar also deteriorates rapidly when exposed to sunlight.



...so i guess you wouldn't recommend to buy a (15 years old former reserve with 0 rides on it) canopy with kevlar lines to jump it as a main if you would like to put let's say 250 skydives on it?

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Back in the mid-1990s, we had an abysmal malfunction rate on first-generation, tandem mains.
After 20 jumps, we used to take Strong tandem reserves out of service.
We replaced their Kevlar suspension lines with
Dacron and put more than 300 jumps on them before finally retiring them.

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You have to be really careful to keep Kevlar lines away from hook Velcro or they WILL fray. Last year SEI replaced several lines on one of our reserves because of Velcro fraying.



Rob,
The same problem exsists on the PD reserves that have uncoated 725 Spectra as well. I have had to replace several lines over the years from Velcro damage.

The damage can occur from packing, but most riggers do a really good job of keeping the hook Velcro covered while packing and stowing the lines.

Most of the damage I have found was after use of the parachute.That makes me wonder why PD uses the stuff uncoated. No one else does.

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Spectra is by far the most popular suspension line these days.



As far as reserves, I believe that to be true also.

As far as mains, I believe that to be not true these days.


MEL
Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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Back in the mid-1990s, we had an abysmal malfunction rate on first-generation, tandem mains.
After 20 jumps, we used to take Strong tandem reserves out of service.
We replaced their Kevlar suspension lines with
Dacron and put more than 300 jumps on them before finally retiring them.



thanks for your answer.

well, there is this guy who would sell his raven (as already mentioned: 15 years old former reserve with 0 rides on it) and told me that in his opinion/experience the KEVLAR-lines are without doubt not as robust as spectra lines, but should allow 400 skydives as a main...

...untrustworthy?

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Why do you want dacron?



I bet Tonto's thinking about opening shock.

Honestly I know that my chance of opening at terminal with a reserve is very, very slim for several reasons so spectra lines do not bother me on a reserve.

Said that I would not BASE jump (packed jumps) and do CRW with a canopy with lines other than Dacron.
Memento Audere Semper

903

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The main reason (I apologize for the pun) our old (20 jump) reserves with Dacron was that the fashion for F-111 tandem mains. We just cut new line to the same dimensions as tandem mains.
Thankfully, that entire generation of F-111 tandem mains has quietly faded from the skies.

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The damage can occur from packing, but most riggers do a really good job of keeping the hook Velcro covered while packing and stowing the lines.

Most of the damage I have found was after use of the parachute.That makes me wonder why PD uses the stuff uncoated. No one else does.



Can anyone from PD explain?

It is one of the few reasons that I don't like working with their reserves. (The other is white thread on white fabric being hard to inspect... but I digress).

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

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The coated line sticks together. Over time it changes the deployment times. But I guess it's not something we should worry about because everyone repacks their reserve at or before 120 days and they never see the heat from the trunk of a car or anything crazy like that. :)
We have tested reserves that were packed for 1 day, 30 days, 120 days, up to two years (not saying you can jump a rig for 2 years and be fine without repacking it, because there are a lot of other problems that can happen with a rig in operation, these things were just on a shelf) and with the uncoated fabric and uncoated lines, they were all the same deployment times. Start putting sticky stuff in there and things change...

Isaiah

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Isaiah,
I personally have never seen any sticky lines in the field on any other reserve canopy that would cause a problem with a deployment or it's deployment times.

Actually, the slicker coated lines should help speed up the openings!

I do know that you guys use a synthetic coated 725 Spectra (which you guys call 825 in-house) on your mains rather than the standard coating that everyone else uses.

I get the same line from CSR (synthetic coating) to reline PD canopies, but still have not noticed any stickiness in the lines. The same applies to the standard coating.

Maybe you guys need to use the standard coating instead. Again, no other reserve manufacturer has had a problem with their products and that is what they use.

One of the first rules in engineering is "real" damage problems (damaged lines) take precedence over theoretical damage (probable sticky lines) always.

You would make most riggers happier!;)

It is the biggest complaint of your reserves. And in fact, probably the only one now! So why not fix it?


Blue ones,
MEL
Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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The coated line sticks together.



Have you actually seen this happen? Out of all the reserves I've inspected and packed, and all the reserves my colleagues have inspected and packed, the sticky line phenomenon has yet to rear its ugly head.

Oh, I'm sure it's possible, but I've heard about it since the beginning of my career and have yet to see any form of proof that it occurs.

I’m a big fan of PD reserves but I’m not a fan of the lines.
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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sorry to butt in, im still a newbie (and buying a reserve soon)

i am slightly confused by all these line coatings.

what is it exactly you dont like about PD reserve lines? should i seriously consider this when buying a reserve? (i mean, so many people have PDs)

if you want, PM me so i dont interrupt your discussion too much.

many thanks,

caspar
"When I read about the evils of drinking, I gave up reading."

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