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Double stowing suspension lines

 

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Poll: Double stowing suspension lines
I'm a big believer in 'double stowing'. The tighter, the better. 33 / 24%
Only if I have to, and never on the locking stows. 55 / 40%
I never 'double stow'. It's not necessary and can create it's own problems. 49 / 36%
137 total votes
 
brettpobastad  (D 12823)

Jul 17, 2005, 2:56 AM
Post #1 of 98 (3384 views)
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Double stowing suspension lines Can't Post

I'm curious as to jumpers and riggers opinions on the relative merits and potential side affects of 'double stowing' canopy suspension lines when packing.


DBCOOPER  (D 24112)

Jul 17, 2005, 5:25 AM
Post #2 of 98 (3309 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

I use to.I find I get better openings using the small rubber bands.


tdog  (D 28800)

Jul 17, 2005, 6:34 AM
Post #3 of 98 (3287 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

The way my bag closes (newer ZP in a tight fit) my locking stows never need a second wrap to make them tight...

But the 2 non-locking ones I always double stow.

I am sure it has been discussed before on other threads, but anyone have any first hand knowledge of this causing mals??? If so, then I will change - as right now the poll seems to show I am in the minority...


klafollette  (D 26795)

Jul 17, 2005, 6:38 AM
Post #4 of 98 (3285 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

My experience has been that small bands on the lower lines get too loose after a couple jumps if single wrapped, and are too tight when double wrapped, so I double wrap large bands, and seems just right. On the locking stows, I single wrap the inside 2, and double wrap the outside two.


linestretch  (D 21060)

Jul 17, 2005, 7:52 AM
Post #5 of 98 (3255 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

have always double stowed. If they are big rubber bands, no problem.


riggerrob  (D 14840)

Jul 17, 2005, 8:38 AM
Post #6 of 98 (3245 views)
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Re: [linestretch] Double stowing suspension lines [In reply to] Can't Post

I prefer small rubber bands, but when they are not available, I just double wrap large bands.
I firmly believe that tight rubber bands can prevent all sorts of nasty out-of-sequence deployments. I don't care whether you use rubber bands, Tube Stows, sili-whatchamacallits, etc. as long as the stretchy things keep a firm grip on the line group.

Double-wrapping makes a negligible different in the incidence of bag-locks.


bob.dino  (E 2185)

Jul 17, 2005, 4:01 PM
Post #7 of 98 (3164 views)
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Re: [riggerrob] Double stowing suspension lines [In reply to] Can't Post

If the big band is too loose I double-stow/knot it on the d-bag, leaving a single stow around the lines.


(This post was edited by bob.dino on Jul 17, 2005, 4:09 PM)


Hooknswoop  (D License)

Jul 17, 2005, 4:06 PM
Post #8 of 98 (3161 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

My one and only bag lock was on a tandem because the packer double stowed the lines. Use the right sized rubber bands. They don't have to hold too tight. Just the locking stows must hold the lines snug.

Derek


mjosparky  (D 5476)

Jul 17, 2005, 7:26 PM
Post #9 of 98 (3116 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

I jump a bag that has just 2 locking stows. The rest of the lines go in a side pocket. As long as the bag is held closed until line stretch what you do with the lines will not effect the opening of the canopy. The tighter your stows the more chance of bag whip which can cause the bag to spin.

Sparky


Hooknswoop  (D License)

Jul 17, 2005, 8:00 PM
Post #10 of 98 (3108 views)
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Re: [riggerrob] Double stowing suspension lines [In reply to] Can't Post

Quote:
I firmly believe that tight rubber bands can prevent all sorts of nasty out-of-sequence deployments.

No-Stow D-bags seem to work OK, as do reserve free-bags.

Derek


mjosparky  (D 5476)

Jul 17, 2005, 8:06 PM
Post #11 of 98 (3103 views)
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Re: [riggerrob] Double stowing suspension lines [In reply to] Can't Post

In reply to:
I firmly believe that tight rubber bands can prevent all sorts of nasty out-of-sequence deployments.

Without some way to stage the deployment you get this. (see attachment)

But you only need the locking stows to keep the bag closed until line stretch to get a staged deployment.

Sparky
Attachments: Deployment.jpg (56.6 KB)


Avion  (Student)

Jul 17, 2005, 8:08 PM
Post #12 of 98 (3102 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

This is one of my posts from another thread.

Quote:
I was having inconsistent openings with my Spectre. Some soft, some harder, with the same packing. I asked some of the PD test jumpers that where around, and they said pull tension on the line stows should be between 7-12lbs. I noticed mine were like 3lbs.

So, with spectra lines, I triple wrap large bands above the cascades, that's the two locking stows and one more, and double wrap small bands on all the rest. I now have good pull tension on all the stows and my openings since have all been consistent. With dacron lines I double wrap large bands above the cascades and single wrap small bands below them.

Apparently, loose stows allow a semi-line dump to happen, and surprisingly that can have a significant effect on the opening.

With some more thought on this, I was wondering if loose stows allow the bag to rise more quickly and the canopy to be more quickly extracted from the bag resulting in a more abrupt inflation of the canopy. This is basically aproximating a case of line dump.

If the stow are made to have the proper tension, line stretch and canopy extraction from the bag progresses in a slower more orderly manner.


(This post was edited by Avion on Jul 17, 2005, 8:17 PM)


mjosparky  (D 5476)

Jul 17, 2005, 8:13 PM
Post #13 of 98 (3098 views)
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Re: [Avion] Double stowing suspension lines [In reply to] Can't Post

In reply to:
This is one of my posts from another thread.

Quote:
I was having inconsistent openings with my Spectre. Some soft, some harder, with the same packing. I asked some of the PD test jumpers that where around, and they said pull tension on the line stows should be between 7-12lbs. I noticed mine were like 3lbs.

So, with spectra lines, I triple wrap large bands above the cascades, that's the two locking stows and one more, and double wrap small bands on all the rest. I now have good pull tension on all the stows and my openings since have all been consistent. With dacron lines I double wrap large bands above the cascades and single wrap small bands below them.

Apparently, loose stows allow a semi-line dump to happen, and surprisingly that can have a significant effect on the opening.

How can anything that happens before the canopy comes out of the bag have any effect on opening. The canopy is still folded up sitting in the bag until the locking stows release. I do not believe there is anything called "line dump" or it would happen on every reserve opening.

Sparky


Avion  (Student)

Jul 17, 2005, 8:20 PM
Post #14 of 98 (3095 views)
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Re: [mjosparky] Double stowing suspension lines [In reply to] Can't Post

I imagine that does happen every reserve deployment. That's one of the reasons that reserves open so fast besides the big hole in the slider and larger cross ports, aye? Wink


(This post was edited by Avion on Jul 17, 2005, 8:22 PM)


tso-d_chris

Jul 17, 2005, 8:29 PM
Post #15 of 98 (3087 views)
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Re: [Avion] Double stowing suspension lines [In reply to] Can't Post

In reply to:
I imagine that does happen every reserve deployment. That's one of the reasons that reserves open so fast besides the big hole in the slider and larger cross ports, aye?

If a reserve deploys properly, there is full line stretch before the canopy comes out of the freebag. It matters not at that point whether there is a slider or cross ports at all.


Avion  (Student)

Jul 17, 2005, 8:38 PM
Post #16 of 98 (3084 views)
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Re: [tso-d_chris] Double stowing suspension lines [In reply to] Can't Post

Are you actually saying that the design of a reserves slider and cross ports lacks any bearing on the speed of a reserves deployment?


(This post was edited by Avion on Jul 17, 2005, 8:40 PM)


Hooknswoop  (D License)

Jul 17, 2005, 8:49 PM
Post #17 of 98 (3076 views)
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Re: [Avion] Double stowing suspension lines [In reply to] Can't Post

Quote:
I imagine that does happen every reserve deployment. That's one of the reasons that reserves open so fast besides the big hole in the slider and larger cross ports, aye?

Ever jump a reserve set up as a main, it opens the same.

Derek


Avion  (Student)

Jul 17, 2005, 8:55 PM
Post #18 of 98 (3072 views)
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Re: [Hooknswoop] Double stowing suspension lines [In reply to] Can't Post

No, but I'm planning on Demoing a PD193 to do that, after I get a little better with my 210. I just jumped with one of my buddies when he was demoing a PD160R, he said he just about sh#t himself evey time it opened, and that was only hop-n-poping it.


(This post was edited by Avion on Jul 17, 2005, 8:59 PM)


Hooknswoop  (D License)

Jul 17, 2005, 8:58 PM
Post #19 of 98 (3065 views)
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Re: [Avion] Double stowing suspension lines [In reply to] Can't Post

Right, that is because tight line stows do not make a canopy open soft and loose stows do not make a canopy open hard. Openings depend on the canopy and airspeed. Only the locking stows need to hold.

Derek


tso-d_chris

Jul 17, 2005, 8:59 PM
Post #20 of 98 (3062 views)
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Re: [Avion] Double stowing suspension lines [In reply to] Can't Post

In reply to:
Are you actually saying that the design of a reserves slider and cross ports lacks any bearing on the speed of a reserves deployment?

Prior to the canopy coming out of the freebag, those things have no bearing. At that stage of the deployment the canopy has yet to be exposed to the relative wind.


sundevil777  (D License)

Jul 17, 2005, 9:01 PM
Post #21 of 98 (3057 views)
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Re: [Avion] Double stowing suspension lines [In reply to] Can't Post

In reply to:
Are you actually saying that the design of a reserves slider and cross ports lacks any bearing on the speed of a reserves deployment?

That does matter to the inflation time, where most of the opening shock of a hard opening exists, but the line stows only affect the snatch force that stands you up before the inflation.


Avion  (Student)

Jul 17, 2005, 9:25 PM
Post #22 of 98 (3045 views)
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Re: [sundevil777] Double stowing suspension lines [In reply to] Can't Post

Well, all I know from my own experience, limited as it is, Wink is that before I started stowing the lines the way I do now, one out of evey 4 or 5 openings would be a little harder than the rest. Less than really hard but noticably harder than usual. As I explained I noticed some stows were looser than recommended, and after I started stowing them so that they all have good tension, my openings have all been about the same, consistently. So, all I'm trying to say is that line stows seem to have at least some influence upon deployments, little as it may be.

I thought that I should add that I'm talking about the difference basically between freestowing the lines in the bottom of the container and stowing the lines with bands so that they have 7-12lbs of pull tension.

An out of sequence deployment, where the canopy come out of the bag and starts inflating before the lines are completely stretched is another issue.


(This post was edited by Avion on Jul 17, 2005, 10:05 PM)


smiler  (D 102162)

Jul 18, 2005, 2:24 AM
Post #23 of 98 (2993 views)
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Re: [Hooknswoop] Double stowing suspension lines [In reply to] Can't Post

Quote:
My one and only bag lock was on a tandem because the packer double stowed the lines.

Can you explain how double stowing can cause a baglock? Was the packer using tube stows or normal bungees?


Hooknswoop  (D License)

Jul 18, 2005, 6:32 AM
Post #24 of 98 (2952 views)
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Re: [smiler] Double stowing suspension lines [In reply to] Can't Post

Normal large bungees. On the ground I put my food on the drogue bridle and pulled on the lines hard and they wouldn't release. The angle the bag was turned to by pulling from the bridle and lines put tension on 2 double wrapped stows so that they shared the force. When seeing how lines un-stow, too many people hold the d-bag and pull the lines off, it is much different if you anchor the container and pull on the bridle.

Canopies open normally without having tight line stows. All the lines stows do is cause the lines to release as the bag moves away from the jumper and tighten the lines every time a stow puts tension on them. Then the lines get some slack when the stow releases. Then they tighten back up as d-bag gets farther from the jumper to the next stow. As long as the canopy stays in the D-bag until after all the lines are out and taut, the canopy will open normally. Too tight of stows and you will get a bag lock. I believe snatch force has more to do with the speed of the jumper and the size of the canopy when it is out of the bag with the slider all the way up against the stops and the size of the slider. The more that comes out the bag, the more snatch force, that initial deceleration.

Derek


Designer  (D 5771)

Jul 18, 2005, 7:13 AM
Post #25 of 98 (2934 views)
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Re: [brettpobastad] Double stowing suspension lines [In reply to] Can't Post

Not sure which is the correct answer?Some customers "Demand" that you never double stow.These are mostly the smaller more high performance parachutes.On the bigger parachutes I don't think it makes much of a difference?thoughts?


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