Forums: Skydiving: Gear and Rigging:
Spectra/dacron lines

 


freefaller76  (Student)

Nov 17, 2003, 4:35 PM
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Spectra/dacron lines Can't Post

What's the difference between spectra and dacron lines?


mjosparky  (D 5476)

Nov 17, 2003, 10:52 PM
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Re: [freefaller76] Spectra/dacron lines [In reply to] Can't Post

Look in Poynter's manual, Vol. II page 79.


(This post was edited by mjosparky on Nov 17, 2003, 11:40 PM)


Squeak  (E 1313)

Nov 18, 2003, 2:40 AM
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Re: [mjosparky] Spectra/dacron lines [In reply to] Can't Post

SlySlySly hehehe and if ya havn't got the manualLaughLaughLaugh


darkwing  (D 4164)

Nov 18, 2003, 5:34 AM
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Re: [freefaller76] Spectra/dacron lines [In reply to] Can't Post

spectra is thinner for the same strength. Dacron lasts longer. Most modern canopies use spectra. Higher performance ones use yet other kinds.


mr2mk1g  (C 103449)

Nov 18, 2003, 5:36 AM
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Re: [freefaller76] Spectra/dacron lines [In reply to] Can't Post

dracron are those bigg ass hairy lines you often see on student canopies or CRW rigs.

Spectra are the "micro lines" those thin white ones most sport rigs have today.

if you want a more technical answer I can't help


Premier skydiverek  (C License)

Nov 18, 2003, 7:04 AM
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Re: [freefaller76] Spectra/dacron lines [In reply to] Can't Post

In reply to:
What's the difference between spectra and dacron lines?

Check this thread:

http://www.dropzone.com/...i?post=615050#615050

Smile


mjosparky  (D 5476)

Nov 18, 2003, 12:40 PM
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Re: [Squeak] Spectra/dacron lines [In reply to] Can't Post

In reply to:
SlySlySly hehehe and if ya havn't got the manualLaughLaughLaugh

Then your tech. library is lacking.Tongue


billbooth  (D 3546)

Nov 18, 2003, 5:33 PM
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Re: [skydiverek] Spectra/dacron lines [In reply to] Can't Post

Anyone who doubts that suspension line stretch is a factor in reducing the opening shock felt by a jumper, should make a bungee jump...only replace the normal stretchy bungee cord with a stainless steel cable. What's going to happen when you hit the end of that steel cable? Your leg is going to be torn off, that's what. Now remember, Spectra line stretches about as much a steel cable.


Hooknswoop  (D License)

Nov 18, 2003, 5:46 PM
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Re: [billbooth] Spectra/dacron lines [In reply to] Can't Post

Quote:
--------------------------------------------------------------------------------

Anyone who doubts that suspension line stretch is a factor in reducing the opening shock felt by a jumper, should make a bungee jump...only replace the normal stretchy bungee cord with a stainless steel cable. What's going to happen when you hit the end of that steel cable? Your leg is going to be torn off, that's what. Now remember, Spectra line stretches about as much a steel cable.

I completely agree with that.

How much does Dacron line stretch? How much of an impact does that make on opening with 10-15 feet times 12 lines (not counting B and D lines)?

Along the same lines (pun inteneded), I wouldn't bungee jump with Dacron line either.

Derek


billbooth  (D 3546)

Nov 18, 2003, 7:13 PM
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Re: [Hooknswoop] Spectra/dacron lines [In reply to] Can't Post

My tests show up to a 300% increase in opening shock felt by the jumper using Spectra vs. Dacron suspension lines. It is not always that much different. It depends on how quickly the force is applied...and canopy makers have done a good job of designing canopies that open slowly enough to allow the routine use of Spectra. However, when a rare hard (quick) opening happens, Spectra lines will definitely make it hurt more.


FrogNog  (C 34484)

Nov 18, 2003, 8:31 PM
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Re: [billbooth] Spectra/dacron lines [In reply to] Can't Post

In reply to:
My tests show up to a 300% increase in opening shock felt by the jumper using Spectra vs. Dacron suspension lines. It is not always that much different. It depends on how quickly the force is applied...and canopy makers have done a good job of designing canopies that open slowly enough to allow the routine use of Spectra. However, when a rare hard (quick) opening happens, Spectra lines will definitely make it hurt more.

Ah, Bill, what do _you_ know? Wink

Seriously, though, 4x pain on a slammer sounds really icky. But Dacron lines doesn't impress the girliez. Easier to stow IMO, though.


mjosparky  (D 5476)

Nov 18, 2003, 11:10 PM
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Re: [billbooth] Spectra/dacron lines [In reply to] Can't Post

In reply to:
My tests show up to a 300% increase in opening shock felt by the jumper using Spectra vs. Dacron suspension lines. It is not always that much different. It depends on how quickly the force is applied...and canopy makers have done a good job of designing canopies that open slowly enough to allow the routine use of Spectra. However, when a rare hard (quick) opening happens, Spectra lines will definitely make it hurt more.

Braided nylon has a minimum elongation, stretch, of 20% which can be 100% greater than dacron. But braided nylon is not cool.Tongue


relyon  (D 18973)

Nov 19, 2003, 7:02 AM
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Re: [billbooth] Spectra/dacron lines [In reply to] Can't Post

In reply to:
...only replace the normal stretchy bungee cord with a stainless steel cable. ...

The point about Spectra's modulus being the same as a steel cable is well taken, but bungee jumping and parachute deployment are apples and oranges. Replace the bungee cord with Dacron in the example and the same thing will happen.

Bob


billbooth  (D 3546)

Nov 19, 2003, 10:37 AM
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Re: [relyon] Spectra/dacron lines [In reply to] Can't Post

Believe it or not, someone actually did make a "bungee" jump with a Dacron line, and it did tear his foot off. I only used bungee cord vs. Spectra as an example everyone could understand.



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