Knot slippage on Reserve Closing Loop, BUT only on MY Jav

[ZigZagMarquis 9]

Okay, here's a weird one for all my brother and sister riggers out there in the verse.

I've experienced this a couple of times, but only when packing MY Javelin... not anyone else's Jav, just MINE.

When doing an I&R on the reserve in my Jav, I make a new Cypres closing loop (actually I do so each and every repack cycle on all reserve pack-jobs I do).

I make the closing loop (finger trap), tie it off with a figure-8 and then a regular overhand knot afert that, route it through the Cypres washer... blah blah... all as per the instructions. Before putting it in the rig, I "pre-stress" it as best I can, holding the washer between two fingers in my fist in one hand and pulling on a screwdriver passed through the loop on the other to tighten / set the knots as much as possible... the goal being the "finished" length to be slightly less then the desired reserve closing loop length. Install the new loop, goop it and off with the rest of the reserve pack-job.

I get to the point where I've got the reserve bagged, lines stowed, canopy within freebag in the reserve pack-tray, reserve risers routed, 1st and 2nd flaps closed... etc. etc... and when compressing the pilot chute or more likely when closing the 3rd flap / bottom flap on top of the pilot chute, the knots in the Cypres loop / reserve closing loop "slip" and now the reserve loop is now like a 3/4" too long and I have to go back and shorten it, make a new one, or tie another knot in it above the initial two.

Its really infuriating!

OBTW, I do not use a positive tension device... just one of those Sandy Reed / R.I. strap w/ an old B12 hook sans gate specials.

AND like I said, this has happend a coupld of times, but only on MY RIG. Never on any other rig I've packed a reserve on INCLUDING a buddy of my that has the same model Jav (J3K) and Reserve (PD160R)... although I can't believe the reserve type has anything to do with it.

Okay, I don't have 1000s and 1000s of reserve I&Rs like some of y'all out there, but I do have about 100 reserve I&Rs... w/ 3 saves.
Anyway.... y'all's

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[Hooknswoop 19]

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I make the closing loop (finger trap), tie it off with a figure-8 and then a regular overhand knot afert that, route it through the Cypres washer... blah blah... all as per the instructions. Before putting it in the rig, I "pre-stress" it as best I can, holding the washer between two fingers in my fist in one hand and pulling on a screwdriver passed through the loop on the other to tighten / set the knots as much as possible... the goal being the "finished" length to be slightly less then the desired reserve closing loop length. Install the new loop, goop it and off with the rest of the reserve pack-job.

The manual calls for a sureon's knot, not a figure 8. That might be part of it.

I start with a long loop with a singleknot at the end with the washer already on it. To pre-stretch it, I use a stainless steel knee plate and packing paddle as the anchor and a T-bar through the loop to pull on it. I pull it hard to get it set. Then I mark where the knot should be, slider the washer past the mark and tie the knots. Then I pre-stretch it again.

Makes for exactly the same length loop every time.

Derek
Derek

[mark 107]

Sometimes there's a little silicon gel on the underside of the closing loop plate grommet. Shouldn't affect the pack job at first, but could wick down to the knot over time. Doesn't sound like that's the case for you.

I bought a batch of pre-made loops once. There was so much gel that some squeezed out while I tied the knots; the knots would just roll off the end of the loop. Since you are making your own loops, this doesn't sound likely either.

You might try using the Aerodyne Icon knot/washer method, which traps the knot under part of the loop and is more resistant to slipping.

Mark

[JustChuteMeNow 0]

The cypress manual calls for a double overhand knot (which is the first part of a surgeons knot) and then another overhand knot to lock the first ones in place. I also finger trap the crpress loop all the way down to where I do the knot.

I prestretch the knot by placing the loop in the leg of my sewing machine and this allows me to get some great leverage for the prestretch. I have not had a knot come loose yet doing this. I did have problems when I just tried to use a screwdriver and my hand for the prestretch.

Like you said blah blah blah there are many ways to ensure the correct length blah blah blah

Think of how stupid the average person is and realize that statistically half of them are stupider than that.

[Hooknswoop 19]

I thought the manual called it a surgeon's knot, oops. Definately not a figure 8 knot though.

I think that is the secret, putting a lot of force on it to pre-stretch it.

Derek

[ZigZagMarquis 9]

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HnS said:
The manual calls for a sureon's knot, not a figure 8. That might be part of it.

Yes, I tie the knot as per the manual, but was explaining it badly...

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HnS said:
I start with a long loop with a singleknot at the end with the washer already on it. To pre-stretch it, I use a stainless steel knee plate and packing paddle as the anchor and a T-bar through the loop to pull on it. I pull it hard to get it set. Then I mark where the knot should be, slider the washer past the mark and tie the knots. Then I pre-stretch it again.

Ooooohh! That's a good idea / technique... thanks!

I have to repack the reserve in my B/U rig tomorrow, I'll try this then.

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Mark said:
Sometimes there's a little silicon gel on the underside of the closing loop plate grommet. Shouldn't affect the pack job at first, but could wick down to the knot over time. Doesn't sound like that's the case for you.

I bought a batch of pre-made loops once. There was so much gel that some squeezed out while I tied the knots; the knots would just roll off the end of the loop.

Well, too much of a good thing isn't always better... over gooping the loop may be a factor.

[Hooknswoop 19]

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OooooHhh! That's a good idea / technique... thanks!

I wish I could take credit for it, but I didn't come up with it. I picked it up a long time ago, don't remember from who.

Derek

[tuffyjensen 0]

Sewing machine leg works great, but not every rigger has one. Another way to pre-stretch. If you have a positive closing device, stick the cyrpes loop with the washer on it, through the hole and then use the handle through the loop. This gives you the handle and the closing device to pull on (behind your head works best). Before opening the reserve note if you feel the loop should be shorter or longer. Measure the old loop from washer to loop tip (example 3"). To make the new loop the correct length you tie the knot close to the washer, it will usually stretch about a 1/2 so start a 1/2 inch short of the desired length (2 1/2 in this example). You will figure out your stretch distance after a few times and end up real close every time.

Holding on to the washer with your fingers just won't get it stretched, unless you're incredibly strong

Be Safe and Have Fun, in that order!
Tuffy

[riggerrob 643]

Yes, Javelins are very fussy about loop length.

Since my knots usually "set" 1/2 an inch to 3/4 of an inch - during the first pack job - I usually tie a new loop 1/2 an inch to 3/4 of an inch shorter than the loop it replaces.
It also takes an hour or so for the loop to full stretch. So I usually compress the pilot chute and leave a sand bag on the rig for a half hour - while I do something else productive (i.e. paperwork). Then I close the bottom flap and leave the sand bag on it for another half hour (while I straighten out the main), etc.

[riggerrob 643]

OBTW, I do not use a positive tension device... just one of those Sandy Reed / R.I. strap w/ an old B12 hook sans gate specials.

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

Hey!
I taught Sandy that trick.
In exchange, Sandy taught me a few hundred rigging tricks when we worked together.

[ZigZagMarquis 9]

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OBTW, I do not use a positive tension device... just one of those Sandy Reed / R.I. strap w/ an old B12 hook sans gate specials.

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

Hey!
I taught Sandy that trick.

So YOU'RE the one to blame for that neck-breaker tourture device!!

[riggerrob 643]

I tired adding an old leg pad, but it seems that only girls and sissies need padding around their necks!
Hee!
Hee!

[ZigZagMarquis 9]

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I tired adding an old leg pad, but it seems that only girls and sissies need padding around their necks!
Hee!
Hee!

Well, it doesn't hurt like a helmet glued to your head or anything like that...

[mnealtx 0]

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Well, it doesn't hurt like a helmet glued to your head or anything like that...

That almost sounds like a "it happened to me" story....

Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

[seal_S49 0]

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Sometimes there's a little silicon gel on the underside of the closing loop plate grommet.

yep

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There was so much gel that some squeezed out while I tied the knots

yep

These types of contamination have been my only source of knot slippage if the loops have been fingertrapped & tied properly.

For that matter, any source of any lubricant can lead to knot slippage. That's why I take these precautions when making loops:

1) Clean all used "smiley" washers with solvent and dry w/ compressed air before re-use.

2) De-grease my hands (& tools) before making/handling loops to remove any possible: CYPRES lube, sewing-machine oil, cut-away cable lube, body oil or sweat, cooking oil from those greasy fries I ate for lunch--you get the idea.

3) Apply a just-adequate amount of silicone lube only after the loop is installed, prior to feeding thru cutter or closing any flaps of course.

[ZigZagMarquis 9]

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Quote

Well, it doesn't hurt like a helmet glued to your head or anything like that...

That almost sounds like a "it happened to me" story....

It didn't happen to me... but close...