stows on mains vs reserve

[rendezvous 0]

How differently are the lines stowed on a reserve. Is it true that only locking stows are made on it, the rest of the line is packed in
a pouch. If so why isn't a similar thing adopted for the main. What are the advantages and disadvantages of the two techniques.

[billvon 3,072]

>How differently are the lines stowed on a reserve. Is it true that only locking
>stows are made on it, the rest of the line is packed in
>a pouch.
On most freebags, yes.
>If so why isn't a similar thing adopted for the main.
Such a system is used on CRW mains and BASE mains, although the pocket is generally on the tail, not the bag. It is also used in the Marta sleeve, a "bag" used for BASE jumping. It gives somewhat better on-heading performance. It's a bit harder to pack. The velcro that most pouches are closed with wears out eventually.
-bill von

[polarbear 1]

I've always thought of it as fewer line stows=less chance of a baglock. Having only two line stows in the center of the bag (as opposed to the outside of the bag, where most main bags have stows) translates to greater chance of an on-heading (or un-twisted) opening.
Also, reserves are designed so that they have a chance to open in a horseshoe condition. This is why the reserve bridle is so wide and may have some sort of assist device like nylon pockets sewn on it. The idea is that if the reserve PC gets caught/tangled on some part of the jumper, the bridle is supposed to supply enough drag to unstow the lines and alow the reserve to deploy. It takes more force (in my opinion) to strip lines from a line stow rather than a pouch, meaning that the bridle may have an "easier" time getting the reserve out.
Stowing lines in a pouch takes a bit more finese/time to keep them organized. I would also expect that lines in a pouch *may* be more susceptible to line dump.
This is all speculation on my part...I don't really know for sure.

[rendezvous 0]

When the lines from the pouch are extracted all in one go doesnt their sudden extension at terminal cause some kind of a slamming action on the jumper. Also is there any possibility that the lines may get knoted when they leave the pouch or is there something done to prevent that from happening.

[billbooth 10]

I think the main reason most us manufacturers use the free bag system for reserve deployment is inertia. ParaFlite tested and introduced the first square reserve, the Safety Flyer, with it. It worked well, and nobody (except Jump Shack) has seen much reason to change. I also believe that there is less chance of a bag lock with the system.
Why not use it as a main bag system? Some people did at first, but the following problems soon became evident. 1. It takes longer to pack. 2. The Velcro, which holds the line stow pouch shut, wears out quickly, is a pain to replace, and over time, would cause suspension line wear.
Let me clear up one myth right now. The free bag system WILL NOT pull your reserve bag out of its container in the event of a horse shoe malfunction. A horse shoed 16 foot long, 2 inch wide, free bag bridle generates only about 2 pounds of force on the bag at terminal velocity. Most reserve canopies weigh over 5 pounds, not counting force required to extract them from the reserve container, especially if the main container is still closed. What the long wide bridle will do, however, is stabilize the bag, (if you reach back and throw it out of the container) so that it won't tumble through its own lines as it deploys.
So, if you ever experience a horseshoe malfunction of your reserve, don't just lie there and wait to hit the ground, sit up until you feel the reserve bridle hit you in the back of the head, reach back and pull on it until the free bag is out of the container, and then let go. The drag of the bag itself, helped out by the bridle, will then carry it to line stretch. I put out a film about this about 15 years ago, but a lot of people seem to have forgotten.

[polarbear 1]

Interesting...I guess I believed the propaganda that the wider reserve bridle might provide enough drag to deploy a horseshoed reserve. Thank you, that is worth knowing.

[polarbear 1]

Ideally, the lines don't unstow from a freebag pouch all at once. They should be carefully s-folded into the pouch such that they unstow in a smooth, controlled fashion, one layer of the s-fold at a time. It isn't too difficult to pack the reserve in this manner, but in my experience it takes a bit more time and patience then using the rubber bands on a main bag.

[rendezvous 0]

what film would this be ? I'm very new here so I don't really know what all exists out there.

[rendezvous 0]

How much of an affect if any does S folding the lines in the pouch as oppose to using rubber bands to stow them have on the deployment time. I understand that reserves typically deploy much faster than the main. Am I right on that. If so, does that have anything to do with the use of the free bag or is there something else to it too.

[polarbear 1]

I'm afraid I don't know that. I would guess that lines in a pouch would be a little faster, but that is only a guess. Maybe Bill Booth will pay us another visit and answer the question.
And yes, a reserve should deploy faster than a main...they are designed to open fast, while most mains these days are designed to open slower. Part of the difference is in the design of the canopy. Part of the difference is in the way the canopy is packed. I would also expect that part of the difference is in the way that the canopy is deployed (ie extracted from the container, lines unstowed, canopy out of the container but not yet inflated)

[billvon 3,072]

>When the lines from the pouch are extracted all in one go doesnt their sudden
>extension at terminal cause some kind of a slamming action on the jumper.
It is definitely a faster opening than rubber band stowed lines, since the force to unstow the lines is a lot less. At the very least the bag will reach the end of the lines sooner.
> Also is there any possibility that the lines may get knoted when they leave the
> pouch or is there something done to prevent that from happening
Unlikely. Watch a video of a BASE jump and you'll see the lines pay out in a pretty orderly fashion. They don't just "dump out" all at once (at least, not usually.)
>How much of an affect if any does S folding the lines in the pouch as oppose to
> using rubber bands to stow them have on the deployment time.
See above. Not 100% sure for reserves, but that's one of the reasons they are used for BASE - faster, more on-heading openings.
-bill von

[alan 1]

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I would also expect that lines in a pouch *may* be more susceptible to line dump.

My understanding of line dump is that situation occurs when the canopy has exited the bag before line stretch. I've also heard it referred to as canopy dump. So, as long as the locking stows perform their job, the lines stowed in the pouch can dump with no real ill effects. In practice, as billvon, has pointed out, they generally deploy in a fairly orderly manner. My concern would be that the locking stows are secure enough to prevent bag strip and yet not be susceptable to bag lock.
alan

[polarbear 1]

I suspect you're right. That was the reason behind the *may* in my previous post. It was a BIG maybe.

[billbooth 10]

When asked, "all else being equal, would rubber bands on a freebag slow the reserve opening, compared to a line stow pouch?"...The answer, at least on a low speed opening (such as after a breakaway), is yes. If you ever need to open your main on the ground, pull your bag across the floor slowly and see how each rubber band stow "grabs" the lines as they unstow, and therefore "slows" the bags progress. The pouch on a freebag lets the lines out "easier". Also notice that the rubber bands grab the "outside" lines in each stow group, but not the "inside" lines, causing the "inside" lines to leave the stow first. This rather uneven release pattern looks a lot more "messy" on high speed films of deployments than the lines coming out of a free stow pouch do. Ram air canopies don't malfunction, their lines do. Therefore, it would follow that the "cleaner" the lines deploy, the better the chance of a good opening.

[skydiverek 63]

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what film would this be ? I'm very new here so I don't really know what all exists out there.

Inability of the wide bridle to extract a freebaged canopy has been shown in "Mike McGowan's Greatest Hits" movie.

[riddler 0]

It seems that I've also seen reserve bridles that have small pouches sewn to them to assist with pulling on the bridle. Improvement or gimmick? Seems like if you have enough of them, you can easily tip the scales from 2 pounds to the 5 pounds needed to begin to pull up on the reserve, and if you can get the processes started, the extra surface area should be able to finish pulling it out.

[skydiverek 63]

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It seems that I've also seen reserve bridles that have small pouches sewn to them to assist with pulling on the bridle. Improvement or gimmick? Seems like if you have enough of them, you can easily tip the scales from 2 pounds to the 5 pounds needed to begin to pull up on the reserve, and if you can get the processes started, the extra surface area should be able to finish pulling it out.

Rigging Innovations makes such bridles on their Talon rigs (and maybe Voodoo too). Basically, there are small assisting pockets on the bridle that should catch air, adding some drag. Another solution was an additinal reserve PC (with no spring in it) sewn to the bridle - the Catapult system on Reflex. Basically it was a huge pouch added to the bridle. It was a very controversial solutions, debated here many times...

[skydiverek 63]

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A horse shoed 16 foot long, 2 inch wide, free bag bridle generates only about 2 pounds of force on the bag at terminal velocity. Most reserve canopies weigh over 5 pounds, not counting force required to extract them from the reserve container, especially if the main container is still closed.

I know that most reserve canopies weigh 5 pounds on the ground, but don't they weigh less when situated on the falling object (freefalling jumper). Their mass would still be the same, but their weight would be different in this freefalling environmnet, I think. It's like standing on a scale, being in an elevator that descends very quickly - I think our bodies weigh less then, since the "ground" or "base", and the scale is running away from our feet... I know that it is a theory and that reality check - Mike McGowan's movie - shows that wide bridles do not help much in this case, but I was just wondering...

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[riddler 0]

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Rigging Innovations makes such bridles on their Talon rigs (and maybe Voodoo too).

That's probably where I saw it - repacking my Voodoo reserve I've only done it once, so I don't remember too much about it. Question is, how much additional extraction force can this provide?

[Hooknswoop 19]

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I know that most reserve canopies weigh 5 pounds on the ground, but don't they weigh less when situated on the falling object (freefalling jumper). Their mass would still be the same, but their weight would be different in this freefalling environmnet, I think. It's like standing on a scale, being in an elevator that descends very quickly - I think our bodies weigh less then, since the "ground" or "base", and the scale is running away from our feet...

Once we are terminal, we weight the same. Once the elevator stops acclerating (which doesn't take very long), the scale would read our body weight.

Derek

[mjosparky 4]

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When asked, "all else being equal, would rubber bands on a freebag slow the reserve opening, compared to a line stow pouch?"...The answer, at least on a low speed opening (such as after a breakaway), is yes. If you ever need to open your main on the ground, pull your bag across the floor slowly and see how each rubber band stow "grabs" the lines as they unstow, and therefore "slows" the bags progress. The pouch on a freebag lets the lines out "easier". Also notice that the rubber bands grab the "outside" lines in each stow group, but not the "inside" lines, causing the "inside" lines to leave the stow first. This rather uneven release pattern looks a lot more "messy" on high speed films of deployments than the lines coming out of a free stow pouch do. Ram air canopies don't malfunction, their lines do. Therefore, it would follow that the "cleaner" the lines deploy, the better the chance of a good opening.

When a bag with stows deploys the lines, it starts to whip back and forth going from the stow on one side to the stow on the other side. The high speed film that Bill mentioned shows that this can get real ugly at times. With the pouch the lines come straight out and little if any whip. I have been jumping a main "D" bag with a pouch for nearly 5 years. Yes the velcro does wear out, but so far no problems.
Sparky

My idea of a fair fight is clubbing baby seals

[ZigZag 0]

Some years ago there was concern that the snatch force of the reserve P/C might cause bag strip, in other words the two locking stows on the reserve free-bag might break, resulting in an out of sequence deployment.
At that time rubber o-rings were used, instead of the shock-cord (safety-stow ) now found on reserve free-bags. This was also known as the
"table cloth trick effect".
Paraflite Corp. conducted some tests which alleviated
many of the concerns. The o-rings held.
As with base canopies and some CRW configurations,
the d-bag is absent. In this case the canopy is extracted from the container first with subsequent deployment of the suspension lines, hence the tail-pocket.( Very similar to the deployment of sleeveless round canopies). And there have been many jumpers that place the main canopy into the d-bag, apply the locking stows, and then free-stow the lines into the main packtray, with good results.

There are some main d-bags based on the design of the reserve free-bag in circulation. They are being jumped by experienced jumpers, and it is more of an evaluation at this time. Their use is believed to enhance on-heading openings.
This particular design does raise the issue of an out of sequence deployment and partial but not complete bag strip, as the main d-bag is affixed to the main canopy in contrast to a freebag.
My main concern is the combination of snatch force and weak or worn rubber bands on locking stows, commonly used for main packing. Many of us have seen that rubber bands only get replaced when they brake, rather at signs of wear and tear. Other issues may be incompatible pack volume of the canopy in relation to the d-bag, ie., too small a d-bag, stretching the rubber bands to their limits...using stronger bands or shockcord may cause other problems,(baglock?), and the use of the safety-stow
method may be impractical, since one would loose it frequently on deployment.
Evaluations take time, and often problems don't manifest themselves until a large and varied data base is available.