bag dump/bag strip and why it might happen

[Mountainsky1 0]

Don't have a video, here are a couple of recent published pictures from Parachutist. Note the tandem main out of the bag. Note the line dump.

[JohnDeere 0]

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I don't know whether it happens or not, I'm just skeptical. Ultimately if this happened a fraction of the time that it's credited, we'd be seeing direct evidence of it including video.

There was a video posted a several months ago of a tandem bag-strip. It was pretty nasty. I don't have time to search for it, but IIRC it was misidentified as a "line dump" in the thread subject.

I remember the same one but dont know where it was.

Nothing opens like a Deere!

You ignorant fool! Checks are for workers!

[sundevil777 93]

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>I understand what you and billvon are saying, but the condition of relatively
> stretched out locking stows is a common reality, even if it is not the ideal.

Agreed. But you need a pretty pathologic combination of very short bights, very loose stows and a loose canopy to get anything like bag strip. Even with very loose stows, properly sized bights will keep the canopy from coming out, since the loads on the lines will tend to keep the bag closed during acceleration away from the container.

(Not to say that it can't happen, but I think it's far less common than people think.)

No, all it might take is for the first locking stow to break.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[davelepka 4]

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I jump a Hornet 170 with spectra lines. It is in a Javelin J3. I psycho pack (personal reasons). When I get the canopy in the bag, it fits so neatly that I can pull the flap right up to the locking stow bands with no effort. I use small rubber bands for my locking stows (actually for all my stows). The only tension on the locking stows is after I insert the lines into the rubber band.
QUESTION: Is this too loose of a pack job or is this ok?

Keep in mind that what I was talking about was the opposite, bags that are too tight and where the flap doesn't reach the rim of the bag. The lockign stow is then pulled tight to bridge the gap and hold the bag shut. Now the locking stow is under much more tension than usual, and if it was to break, the bag is already halfway open.

That said, your setup sounds fine. The same tension that keeps all of your other stows secure, will keep your locking stows secure as well. You want to make sure you have a nice 2.5" or 3" bight of line in the locking stows, to ensure that they hold tight, even in the event of a little slippage.

There is an extreme opposite, where the bag is too big, and the fit is very loose. In those cases, the canopy itself has too much room to move around inside the bag and during deployment things don't stay the way you packed them.

I don't think that a 170 in a J3 would be that loose. It's probably a vey reasonable fit, and makes for easy packing and a lot of control over what you're putting into the bag.

Keep in mind that the majority of rigs out there have too much canopy stuffed into them. Having a small rig seems to appeal to everyone, not just the guys with the sub 100 main/reserve combos. Even the guys jumping 170s will usually try to buy the smallest rig they can stuff them into. Even if they say it's so they can downsize their canopy with buying a new container, the majority of them will buy a smaller container when they downsize, and end up stuffing a 150 into a rig made for a 135.

If your canopy is on the smaller end of what the manufacturer says will fit, you're on the right track. Very few people can eyeball the difference between a J2 or a J3, but when you get down to packing them, the difference becomes clear. Fast forward that to the 8th pack job on a 90 degree day, and it's that much more of a benefit, and it allows you to bag a cleaner pack job.

[glgflyer 0]

Thanks for that explanation Dave. I now understand what you were saying. I too have seen pack jobs where there appeared to be more canopy outside the bag than inside. Never made sense to me either. Anyway, I really appreciate you answering my question in such a detailed manner.

[JohnSherman 1]

Read:
http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Speedbag&SortBy=DATE_D
and:
http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Rubberbands&SortBy=DATE_D
and:
http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Reserve_Speedbag&SortBy=DATE_D
At our shop we used the Speed Bag on our mains for some number or years. I called my staff together (About 5 masters & 2 seniors at that time) and suggested that we release it as a Reserve free bag. They had all already done that.
Most reciently we recieved a report from the USAF where they started using SPEED bags in 2006. The year before they had had 14 malfunctions on their mains for 850 jumps/year. In 2007 & 2008 they had ZERO malfunctions and in 2009 they had one (A line knot). Marty correct me if I have anything wrong on this.

John Sherman

[ljwobker 2]

I've been the unfortunate recipient of an incredibly hard opening that was almost certainly due to line dump, in turn caused by rubber bands that were too loose. The opening blacked me out and did some nontrivial and permanent damage to my shoulder, so I can very very highly recommend that you NOT put yourself in this position. While not impossible, it would be very difficult for a normal jumper to set the rubber bands tight enough that a properly functioning pilot chute wouldn't deploy them correctly.