New lines and double stows

[haleyes 0]

I just had new Dacron lines (from Spectra) installed, and I'm adjusting to the thickness of them. Should I continue to double stow the beginning set of lines (the ones that close the d-bag) or maybe single stow them instead? What problems can come from the stows being difficult to "release"? Too easy to "release"?

Also, I noticed that my openings (3) have been different with the new lines. Whereas before, the canopy opened "right now", it now takes 4 to 5 seconds to deploy. I see the slider is square, but the canopy takes its time to inflate. Someone suggested that with the new lines, the gromments may be sticking a bit and that in time the canopy will open as fast as it ever did.

True? False? Comments?

larry

[billvon 2,396]

>What problems can come from the stows being difficult to "release"?

In order of severity:

Slow openings, if the PC is small and the main is heavy
Line twist, if the tightness of the stows lets the bag spin during line stretch
Bag lock (rare; they have to be really tight or the PC has to have a problem)

Too easy to "release"?

Hard openings
Tension knots
Line dump (i.e. explosive openings)

[vidiot 0]

Quote

Should I continue to double stow the beginning set of lines (the ones that close the d-bag)

Larry,

I know of one case where a double stowed rubber band knotted up, hooked on the grommet and caused a bag lock. So my advice is to never double stow the rubber bands going through grommets.

Klaus

---

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[AggieDave 6]

Quote

Whereas before, the canopy opened "right now", it now takes 4 to 5 seconds to deploy

That could be due to your canopy being in correct trim with the new lineset, thus it is inflating correctly.

Are you double stowing small rubber bands or using large rubberbands? If you're using large and double stowing them, try switching to small bands.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[skydiverek 54]

Quote

Also, I noticed that my openings (3) have been different with the new lines. Whereas before, the canopy opened "right now", it now takes 4 to 5 seconds to deploy. I see the slider is square, but the canopy takes its time to inflate. Someone suggested that with the new lines, the gromments may be sticking a bit and that in time the canopy will open as fast as it ever did.

Dacron lines have more friction, slowing down the slider descent.

[fudd 0]

Quote

[#003366]I know of one case where a double stowed rubber band knotted up, hooked on the grommet and caused a bag lock. So my advice is to never double stow the rubber bands going through grommets.

Just supporting this statement. I've also been told to NEVER double stow the rubber bands going through the grommets, because it can cause a baglock.[/#003366]

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

[ernokaikkonen 0]

>Just supporting this statement. I've also been told to NEVER double
>stow the rubber bands going through the grommets, because it can
>cause a baglock.

Been there, done that. I had to cut away from a spinning mal that was first briefly bag-locked. I had double-wrapped a locking stow cause I was too lazy to change the band...

I do know a lot of people that double or even triple-stow all their bands without problems... It seems to more of an art than an exact science...

Erno

[riggerrob 558]

I have double-stowed thousands of locking stows and never had a problem.
The trick is matching rubber band tension to line diameter.

[haleyes 0]

large. I've always double-stowed, and I've never had a problem (only 145 jumps though)

[AggieDave 6]

If its not too hard for you to close, try using small rubber bands. It'll give you the advantage of double stowing with out the possible negative side effects.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[PhreeZone 15]

>possible negative side effects.

Like what ones? The band is still connected to the bag at only 2 points and if it fails at either its done.. the whole band fails. If a small band will snap, a large one double stowed will snap in the same place.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[AggieDave 6]

There have been bag locks in the past from double stows and there have been enough pause with them before to cause a wicked spin up, so why play with it when you could just go to a small rubberband? KISS, right?

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[PhreeZone 15]

And there have been bag locks due to small bands. It does'nt really matter what band you use or if you double wrap them or what. All thats really important is if you can break the band. If you can stratch it till it fails, thats all the band is to do.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[AggieDave 6]

Quote

All thats really important is if you can break the band.

Yes I know and understand this point, but when you double stow the band, you're lessening the area available for breakage. Yes, within the double stow the band could and sthould be able to break but with the double wrap, you're reinforcing that area of the band, leaving basically the "ends" of the band where it's looped through the loop on the D-bag. Thus with a new rubberband, by the time it breaks it could have already spun up your canopy, maybe enough to cause a cut away.

With the small band, since it is a single loop of rubber band going over the lines, it is not quite as strong as the double looped at those points, giving a greater chance for breakage over a greater area.

KISS, right?


What are the chances that what I just stated will make a difference? Well, not that great BUT there is that chance.


(I'm assuming you know what KISS stands for

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[slotperfect 7]

Some general comments on stow bands . . .

-Call the manufacturer and see what they recommend. Use that as your starting point and adjust from there.
-Uniformity is important. Don't use "whatever" so you can get packed and manifested. It's OK to use one type of stow band for locking stows (holding the bulk above the cascades) and another for the regular stows, but be uniform from side-to-side.
-If a stow band becomes loose, don't double-wrap it, REPLACE it.
-I jump an almost brand-new Sabre2 190 with 825 microline loaded at 1.32:1, in a Javelin Odyssey with a 3-stow bag. I use standard rubber bands for the locking stows and mini rubber bands for the regular stows.
-Remove any unused stow bands so they are not the potential cause of a malfunction (lines grabbing the open stow band during an asymmetrical bag launch).

Arrive Safely

John

[steve1 5]

This may not be up to the maufacturer's specs., but I use the larger tandem rubber bands for the first two locking stows. The guy I bought my first rig from packed this way for well over a 1,000 jumps without any malfunctions or any signs of a bag lock. I'd appreciate any imput on this practice, but it seems to work well so far. Steve1

[AggieDave 6]

Quote

but I use the larger tandem rubber bands for the first two locking stows

On micro lines? I understand the "if it ain't broke, don't fix it" standpoint, but the idea of using those much stronger tandem rubberbands on a sport rig kinda worries me.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[steve1 5]

Aggie Dave,
I have two rigs. One chute has the larger Dacron lines, and the other is on my Hornet. I think the Hornet's lines are the Micro type. I've been using the tandem bands on both for the first two stows. Both bags are kind of small so there is quite a bit of stretch on the first two locking stows. I'm sure the pull poundage on these stows may be greater than recommended, but all my openings so far have been fine in terms of not having bag lock or line dump. Again one of these rigs has been packed this way for over a 1,000 jumps without problem. I'm no expert, though so I appreciate others ideas on this. Thanks, Steve1

[AggieDave 6]

As stated many times, I am NOT a rigger, although I tend to be around helping with rigging type things with riggers. :) Eitherway, it would make me very nervous. Call up your rigger about it or call the manufacture about it and see what they think.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[haleyes 0]

Thanks for all the good input. I appreciate your help.

larry

[Kirils 1]

You need smaller rubber bands.

"Slow down! You are too young
to be moving that fast!"

Old Man Crawfish

[bobsoutar 0]

I prefer to use single stows for the mouthlock (actually tube stows) and if they are too big just fit smaller ones.
You may well be getting slower openings because of friction on the slider grommets. Also because the bag and lines are heavier than they used to be, the pilot chute has more work to do. You could try a slightly larger pilot chute or leave some extra line unstowed in the bottom of your container.