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SSkydiver

Repack or not???

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Moving the rig from the living room to the closet sounds like good conditions... Pack it if you want to, Personally I'd pack it after you jumped it.

There are lots of parachutes out in the world. A large portion of them sit packed for months on end. Lots of the people who own those rigs don't have internet access and just go jump them :P
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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I'd repack it.



For those of you advocating that the main be repacked, does this also mean that you don't trust your reserve repack after it's five weeks old?

The industry has done experiments with rigs that have been packed for *years*. The results, as I recall, were that the openings were as normal and variable as freshly packed chutes.

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I'd repack it. GRANTED, i barely have 100 jumps, but it's good practice, and if it was 5 weeks for me, i probably wouldn't be able to remember if i rushed it, or if i took a decent time packing it.



Does it make a difference if it was packed sloppy 5 minutes ago or 5 weeks ago? If it's too sloppy to jump (is there such a thing??), it's too sloppy to jump. Time shouldn't really matter.

I'm also very much a non-believer that the amount of time it will take to open will be noticeably different. Maybe I'm wrong but I'd like to see proof.

Dave

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Because the ZP material has a memory



I'm sure it's not very long term if at all.



If it didn't have "memory", it would just lie there on the floor like "F-111". When you pack a ZP main and set it on the floor and squeeze the air out with your body and get up doe's it just sit there or grow? The newwer the canopy, the more pronounced the "memory". When I say slower it may be a second or so.












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So you're saying F111 doesn't have "memory" but ZP does? You'd agree that if it was an F111 canopy, it would open in the same time no matter how long it was packed for?

Eh, I just don't believe it. Any material has a certain amount of stiffness, but memory is a very odd property of some materials. I saw a demonstration a few months ago of something called a shape memory alloy. It's a metal that can be deformed but will return to its original shape when heat is applied. THATs memory. I simply don't believe the fact that ZP seems to grow when you let it sit is anything other than air moving around in it. Then again, I could be wrong.

Dave

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So you're saying F111 doesn't have "memory" but ZP does? You'd agree that if it was an F111 canopy, it would open in the same time no matter how long it was packed for?

Agreed.

Eh, I just don't believe it. Any material has a certain amount of stiffness, but memory is a very odd property of some materials. I saw a demonstration a few months ago of something called a shape memory alloy. It's a metal that can be deformed but will return to its original shape when heat is applied. THATs memory. I simply don't believe the fact that ZP seems to grow when you let it sit is anything other than air moving around in it. Then again, I could be wrong.


It's the stiffness that is the inherent "memory". The air inside is not under pressure to "move around". The stiffness of the material is trying to flatten back out. Thats the memory.













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Memory or not, no one has yet been able to show any difference in openings between a years-old (and well cared for) packjob and one that's only a few days old. I've opened a lot of reserves that have been in rigs for 120 days to several years, and they all look pretty much the same - like bricks of compressed nylon. About the only time they don't look like that is when I pull the pack job back out of the freebag because I don't like it - then you get some reinflation.

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At 5 weeks it wouldn't occur to me to repack it. I've certainly gone longer, with Z-po and with F111, with no issues.

If the rig's been sitting in the sun, or doing anything else that makes you wonder about the integrity of the pack job, then it's time for a repack and inspection of your reserve, as well -- it's most likely been subject to the same conditions.

Wendy W.
There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

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If it was me I would just jump it, but you have to make your own decision. In the amount of time it takes to read all these posts about to pack it or not you could have repacked it.:)

__________________________________________________
Don't take life too seriously. You'll never get out alive.

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ZP is basically F111 with some extra processing done it it. Why ZP spreads is not a "memory" its because its surface is slick. It just slides on its self. New F111 does the same.

Reserves tend not to reinflate like mains do since they get compressed more then a main does and in a more organized manor. If you packed the main in such a way that you were needing positive tension devices to close it and were using something like a plate/spring to spread that level pressure out over the entire pack job it would sit there and be a brick too.

Time is completely meaningless to a pack job openings accourding to 3 major manufactors that I've spoken to about this.
Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

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ZP is basically F111 with some extra processing done it it. Why ZP spreads is not a "memory" its because its surface is slick. It just slides on its self. New F111 does the same.

OK SA,
Roll some alluminum foil and set it down! NO fu##ing memory. Got it>??????? It does't move right????????????????? No f##kiing memory , right????? That's F-111! So some extra processing on the fabrick on ZP makes it stiffer. D'oh! It doesn't f##king move because it's slicker. it moves because it wants to expand because it wants to straighten out! Right????

Reserves tend not to reinflate like mains do since they get compressed more then a main does and in a more organized manor. If you packed the main in such a way that you were needing positive tension devices to close it and were using something like a plate/spring to spread that level pressure out over the entire pack job it would sit there and be a brick too.

Time is completely meaningless to a pack job openings accourding to 3 major manufactors that I've spoken to about this.














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All metal has some amount of springiness. No, a crumpled piece of foil wont return to a flat sheet when you let go, but if you took a strip of it, oiled it up, and bent it into a ring, overlapping a little bit onto itself, I guarantee the diameter would change when you let go. I don't believe that ZP fabric has any special property that causes it to return to the previous shape it was in.

Just like phreezone said, it's all about the slipperiness of it. You're relying on friction to hold the canopy into the cacoon shape when you're packing. ZP has less, therefore if there's any air in it, it'll slip and move. Even in a vacuum I'm sure it would move because of the forces on the material giving way as the material slides over itself.

Dave

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I sometimes repack if I haven't jumped in a while. Not because it's been sitting on the ground for a while, but because I don't remember how I packed.
Sometimes I do a really sloppy packjob at the end of a weekend, just to get it packed quick for transport.
Not a very clever thing to do, but sometimes there's even a little beer involved:P

If I'm lazy I'll jump it anyway, expecting a funky opening.:S

There are only 10 types of people in the world. Those who understand binary, and those who don't.

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