Newbie question re: line stows

[JoeG 0]

Why are all the lines stowed together rather than each side being stowed seperately, either on each side or zig zagging kind of like how shoes are laced?
By this I mean each side crossing the other side between stows.

It seems like since the bridle pulls the deployment bag at the center, when the lines are stowed together it would cause the bag to "dance" back and forth during deployment because of the force being off center, whereas if each side were stowed opposite the other the bag would come out straight, pulling two opposite stows at the same time.

I probably am not explaining this very well, but, if you can picture a shoe being a d-bag and the grommets being stows, if both laces were stowed on the same side at the same time, the shoe is going to tip to the next stow when it is pulled, whereas if it were laced normally it would pull evenly.

Is there any reason why bags aren't stowed this way? Would it make any difference whatsoever? Thanks for your time in answering this newbie's questions!

_________________________________________
"Knowledge is Power!"

[Hooknswoop 19]

I understand what you are saying and you may be on to something. The downside is it would take twice as long to stow the lines and it would be difficult to get them even. Next time I pack a main, I'll mess around with this and see what I come up with.

Cool idea!

Derek

[skybytch 273]

I wonder what potential issues could come of having the line groups crossing each other repeatedly.

Definitely an interesting idea.

[Frenchy68 0]

Quote

I wonder what potential issues could come of having the line groups crossing each other repeatedly.

Definitely an interesting idea.

I'm wondering: if a "stow" takes longer to release than its oposing one, wouldn't the force generated by the "releasing" side make it harder for the stuck one to release?

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

[NWPoul 1]

What will happen if there will be delay of unstowing of one line group relative to other (say left group leave his second stows a bit earlier than the right group leave his second stows)?

Why drink and drive, if you can smoke and fly?

[Stumpy 284]

If i am seeing this right, are you not also going to need twice as many stows, as you only have one half of the lines going through each stow? That is creating a lot of extra complication on top of the bag, not to mention the extra time and care needed to do it. I like the idea but i think it would probably increase the chances of tension knots/ other strange mals.

I guess they are trying for the same end results with these stowless bags by reducing the force needed to free the lines therefore less dancing and a cleaner deployment.

Never try to eat more than you can lift

[mr2mk1g 10]

One DZ I jump at asks packers for their static line gear (direct bag) to do something vaguely similar. The lines are split into their respective sides for the last couple of stows and there are further stows on the actual container for each side of lines. This supposedly helps the bag stay straight as it starts to come away from the student in the first few moments after exit. They're take quite an interest in everything they can do to keep the bag straight during deployment since they're static lining students out of a Let 410 with a relatively high run-in speed.

As for the bag "dancing" with normal stows, that is indeed a known possible source of problems. I think it's Wings for example who have recently developed a bag where the bridle attaches to a triangular extension of the D-bag rather than simply straight to a grommet to help transfer the force of the pilot chute to each edge of the bag in an effort to keep it straight in the air flow and reduce the "dancing" effect.

In recent years a number of manufacturers have moved their stows from the outside edge of the bag to near the outside of the center flap of the D-bag (or at least provided both options on the same bag). This is supposed to help reduce the "dancing" as the bag rotates less before reaching the next stow and starting to rotate the back other way. The downside to this as pointed out by Bill Booth recently is that there are more stows, closer together and thus more potential for lines to become confused or loop over an adjacent stow causing a malfunction. As Stumpy points out above, this would also be a drawback of your idea... although there is no shortage of people wanting to use the middle stow method described above despite Mr. Booth's concerns.

I think if your idea works there may well be people who would try it as they see the risk of their canopy spinning up because of a dancing bag to be greater than the risk of a baglock due to confused lines stows and thus the risk/benefit equation would swing in favor of using it.

[Stumpy 284]

The other issue that just occurred to me (hey, work is boring) is that if the stows on either side do not release at exactly the same time, you run the risk of the stows for the other half of lines beginning to release out of sequence due to the tension from the set "underneath" pulling upwards. That probably doesn't make any sense but i know what i mean.

This would be negated, and the end result the same, by having 4 rows of stows, so you have the left lineset down the left side of the bag and the right set down the right side. The stows would be really short though!!!

Interesting exercise! Don't think i will ever end up being a skydiving gear designer though!

Never try to eat more than you can lift

[Joellercoaster 6]

Or go one better and replace the whole stows/pack tray idea with something like a really big cotton reel, with channels to put the line groups in

--
"I'll tell you how all skydivers are judged, . They are judged by the laws of physics." - kkeenan

"You jump out, pull the string and either live or die. What's there to be good at?

[riggerrob 643]

With static-lines, it helps to make the last couple of stows "short" between the corners of the D-bag and the risers. This helps lift the main risers early in the deployment process, preventing them from entangling with the reserve container.

[riggerrob 643]

If you are really worried about the main d-bag "dancing" then get a line stow pocket similar to a reserve freebag. Line stow pockets meter line out neatly from the center line and only the last two or three stows involve rubber bands. As long as you use the correct size of rubber bands, Tube Stows, Sky Bands, etc. the chance of line dump are insignificant.
I made hundreds of jumps - with my main lines stowed in a pocket - back in the 1980s and some people (i.e. MJOSparky) have thousands of good openings with line stow pockets.
Remember that line stow pockets are standard on the most critical canopies: reserves and BASE.

[wmw999 2,452]

I've been experimenting with making one stow for each line group for the very last one (i.e. just at the riser) so that I can have as little line as possible free in the container. About 15 jumps this way, no problems, but, well, I wasn't getting line twists anyway.

This was in response to a Bill Booth post where he said that film of deploying freestowed lines scared him.

Wendy W.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[CReWLL 0]

We've done just that on some drop tests, for the exact reason you mention. It does work, but the down sides are considerably more wear on the lines from whipping against themselves, plus more complex and longer line-stowing time.

[JoeG 0]

Hey, I was just going through some of my old posts and realized I didn't thank anyone for their time in answering this. Thank You all for your time and thoughts and sorry it took so long to reply.

Hopefully I will get to finish my AFF at Dublin. I kind of lost interest briefly, then it was too cold for me, but im back.

Joe

_________________________________________
"Knowledge is Power!"