Forums: Skydiving: Gear and Rigging:
Mini links stretching on opening

 


RemiAndKaren  (C 2328)

Jun 8, 2001, 7:42 AM
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Mini links stretching on opening Can't Post

I had this missap that could have turned nasty a while ago now. I just wonder how commun it is?

Normal jump, normal landing, but as I was leaving my rig to be packed, I noticed a line hanging around, not connected to anything. On looking closer, I found one of my mini-links completely stretched ; the normal O shape of it was more a C and the lines and riser had managed to just hand on during the canopy ride (i know, lucky).

Could have been real nasty at 500 feet.... and trust me, I check those suckers VERY often now.



Lindsey  (D 17865)

Jun 8, 2001, 7:47 AM
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Re: Mini links stretching on opening [In reply to] Can't Post

That also happened to a friend of mine once.....oh no....nevermind.....wrong incident.....brain fart.....she had a new cut-away handle, and the cable was so short it almost came undone on her ride down, and she landed (if you can call it a landing) holding her riser in her hand! YIKES!



riggerrob  (D 14840)

Jun 8, 2001, 8:35 AM
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Re: Mini links stretching on opening [In reply to] Can't Post

The standard for tightening Maillon Rapide mini links is "finger tight plus 1/4 turn." Any looser and you risk the link unthreading itself. Any tighter and you risk cracking the barrel with similar results.
A drop of Loktite on the threads will help prevent premature loosening as will tight silicone bumpers.



DBTECH  (B 21186)

Jun 8, 2001, 11:34 AM
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Re: Mini links stretching on opening [In reply to] Can't Post

When reading the title of your topic/thread, I assumed that you meant that the link deformed, with the nut properly torqued, because of a gut-wrenching hard opening. Yes, this has happened before!

As far as Rapide link nut tightening/torque is concerned, yes a quarter turn after max finger tightness/torque,
is a "nominal" rule of thumb. I, myself use a torque value/level that is based on my mechanical background/experience.

I am not an advocate of the use of Loctite in this application, as I feel that "proper torque" will assure nut retention, but to each their own. Yes, tight silicone bumpers will act as a "back up."

For your record, here is an excerpt from an earlier topic/thread regarding Mallion Rapide links. db

My new Cobalt 135 came with #4's, which I consider to be the "ideal" Maillon Rapide link.
As far as 3.5 mini's are concerned, I've always felt that they are pushing the envelope to much, with very little strength margin as compared to #4's.

Keep in mind that #5's were the norm before 3.5's.(mini's) 3.5's (mini's) are one half the strength of #5's!
Number 4's fall in the lower middle between 3.5's and 5's.

Note: A #8 Brass or 25mm stainless slider grommet will go over #4's with no problem.

Dave Brownell

Mesa, AZ




Krishan  (D 26361)

Jun 8, 2001, 11:47 AM
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Re: Mini links stretching on opening [In reply to] Can't Post

Question: How is the strength of a soft link or slink compared to that of a 3.5, or a 4 or a 5 for that matter?



DBTECH  (B 21186)

Jun 8, 2001, 1:00 PM
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Excerpt from an earlier post--

I would agree that Slinks would probably fail at a higher number than 3.5 Maillon Rapide links, (mini links) but not likely higher than #4's, and definitely not higher than #5's.

Dave Brownell



weid14  (D 20292)

Jun 8, 2001, 3:41 PM
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Re: Mini links stretching on opening [In reply to] Can't Post

I really think the question ends up being - which will fail first -- the riser or the soft link? I preffer the slinks. I jump mini risers, I think (although I've not researched this) that the riser would fail before the slink so the comparison with the Rapide is moot (in my book anyway)
dave



<FONT SIZE=-1><EM>Edited by weid14 on 6/8/01 03:50 PM.</EM></FONT>


DBTECH  (B 21186)

Jun 8, 2001, 6:45 PM
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Re: Mini links stretching on opening [In reply to] Can't Post

The long term durability of Slinks has yet to be shown/proven.

I would like to see pull test numbers before and after 1000 jumps.
(both pull tests to be done with same size dia pins)

Dave Brownell



spectre230
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Jun 9, 2001, 1:09 AM
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weid14  (D 20292)

Jun 9, 2001, 3:33 AM
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Why would they not last as long as a set of risers? Has their (riser) durability been proven? The load carrying area of the slinks is greater than that of a mini-riser is it not?



DBTECH  (B 21186)

Jun 9, 2001, 1:48 PM
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Re: Mini links stretching on opening [In reply to] Can't Post

My last post read--
The long term durability of Slinks has yet to be shown/proven.

I would like to see pull test numbers before and after 1000 jumps.
(both pull tests to be done with same size dia pins)

Dave Brownell

Spectre230 said--

I think the people that make these links should set a service life for them. I'm sure they don't last forever.
You also need to put a mark with fingernail polish on the link so you can tell when they start to loosen up.
Check them after every jump or make sure your packer does.

DB-- As you can see, I was referring to Slinks here, not Mallion Rapide links, which I consider to have no service time limit in this application.

As far as your comment about the nut on Rapide links needing to be checked on every jump; I totality disagree with this need, as the nut will not loosen up if properly torqued. If your so concerned with this, then use tight silicone slider bumpers that will prevent the nut from turning, or use Loctite.

Dave Brownell

Mesa, AZ











<FONT SIZE=-1><EM>Edited by dbtech on 6/9/01 02:27 PM.</EM></FONT>



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