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"Nice" line-dump tandem photo

 


Premier skydiverek  (C 41769)

May 28, 2012, 2:37 PM
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"Nice" line-dump tandem photo Can't Post

https://fbcdn-sphotos-a.akamaihd.net/...061_1099545355_n.jpg


peek  (D 8884)

May 28, 2012, 2:55 PM
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Re: [skydiverek] "Nice" line-dump tandem photo [In reply to] Can't Post


Thank you very much for posting that. I have been trying to find a true line-dump photo for a long time, because it is my contention that true line-dumps seldom if ever happen, especially on non-tandem gear, while many people describe their hard opening as being caused by a line-dump.

Edited: I guess I need to modify that a bit for tandems. I would hate to think this is happening very often.

Now, as to the cause of the line-dump in the photo...
Let the thread begin!


(This post was edited by peek on May 28, 2012, 3:37 PM)


Premier skydiverek  (C 41769)

May 28, 2012, 2:57 PM
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Re: [peek] "Nice" line-dump tandem photo [In reply to] Can't Post

Amazing this happened on the Sigma (meaning that drogue collapses right after it is released, producing relatively 'low' drag).


(This post was edited by skydiverek on May 28, 2012, 2:58 PM)


Premier cpoxon  (D 11665)
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May 28, 2012, 3:13 PM
Post #4 of 20 (4378 views)
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Re: [skydiverek] "Nice" line-dump tandem photo [In reply to] Can't Post

Here's another, in some, err, haze.
Attachments: TandemLineDump.jpg (39.7 KB)


Deyan  (D 322)

May 28, 2012, 3:38 PM
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Re: [peek] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:

Now, as to the cause of the line-dump in the photo...
Let the thread begin!

It could be everything. From too old / weak rubber bands. Normal size rubber bands instead of the tandem size ones. Lazy packer locking the bag with only 2 stows and putting the rest of the lines on the bottom of the container. Too small bites on the line stows ....

And I think that the term for that on the picture should be a "bag strip"


peek  (D 8884)

May 28, 2012, 4:12 PM
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Re: [Deyan] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
And I think that the term for that on the picture should be a "bag strip"

I would not argue vigorously against you about the term. Indeed, in the 2 pictures we have seen, there appears to be both things happening. "Out of sequence" would probably be a good generic term.

I hope that the people that own those rigs have corrected the problem by now.


riggerrob  (D 14840)

May 28, 2012, 9:31 PM
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Re: [skydiverek] "Nice" line-dump tandem photo [In reply to] Can't Post

The last time I saw a photo that ugly was in 1986. The Vector Tandem Examiner described it as a "spaghetti mess!"

Mind you, first-generation tandem mains were the same as reserves, so we probably would not have noticed the difference!
Hah!
Hah!

Seriously, all the tandem manufacturers have struggled with line-dump/bag-strip and they have invented multiple solutions.

RWS/UPT adopted double-wide rubber bands for civilian tandems and triple-wide rubber bands for (heavier and faster) military tandems.

Strong Enterprises sewed on an extra Anti-Line-Slump flap closed with three loops of bungee cord. SEI also wrote precise standards for bungee cord length. SEI insists that if you can close an ALS bag without a pull-up cord, the bungee loops are too long.
Strong packers whine interminably about how hard it is to close ALS bags. They do not seem to understand that - as an FAA Master Rigger and Strong Tandem Examiner - I am "not far enough up the totem pole" to change the length of bungee cords.
One time I was rushing to meet a sunset load ... when a bungee cord broke, I closed the ALS bag with only two bungee cords. The opening was hard and I have never repeated that mistake!
Bottom line: there are two ways to pack Strong's ALS bags: the factory way and wrong way!

Parachutes de France solved line-dump by using more standard rubber bands as locking stows (6 or 8).

Eclipse added an extra row of rubber bands (down the center-line) to achieve the same goal of "balanced" locking stows.

Jump Shack's "Speed Bag makes the most sense because it uses stock MIL SPEC rubber bands as locking stows and they are in a "balanced" stow configuration.


stratostar  (Student)

May 28, 2012, 9:44 PM
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Re: [riggerrob] "Nice" line-dump tandem photo [In reply to] Can't Post

Just had a TI tell me this weekend, that "line dump" was all made up bullshit. And as proof offered up the new stowless bags as the standard now.


riggerrob  (D 14840)

May 28, 2012, 9:52 PM
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Re: [stratostar] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
Just had a TI tell me this weekend, that "line dump" was all made up bullshit. And as proof offered up the new stowless bags as the standard now.

.....................................................................

Tell him to consider the difference in line weight.

Then tell him to weigh a short, (Vectran, HMA, etc.) line-set for a tiny (sub 100 square foot), solo canopy and compare it with the weight of a long, Dacron line-set for a 400 square-foot tandem canopy.


sundevil777  (D License)

May 28, 2012, 9:54 PM
Post #10 of 20 (4173 views)
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Re: [riggerrob] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
RWS/UPT adopted double-wide rubber bands for civilian tandems and triple-wide rubber bands for (heavier and faster) military tandems.

Using such wide, therefore strong bands reinforces my opinion that it is a lousy philosophy to think that you want locking stows to be able to break so as to prevent a bag lock malfunction. Rubber bands quickly get nicked/cut/flaws that I think may them too likely to break when you don't want them to - right when the most stress is on them.


DaVinciflies

May 29, 2012, 3:11 AM
Post #11 of 20 (4071 views)
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Re: [stratostar] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
Just had a TI tell me this weekend, that "line dump" was all made up bullshit. And as proof offered up the new stowless bags as the standard now.

I believe that the issue here is with the terminology. I use "line dump" to refer to the premature release of non-locking stows, and "bag strip" to mean the premature release of the canopy from the bag. Bag strip is likely to result in a hard opening, whereas line dump is less likely to.

Using the above terminology, both the above photos would fall into the bag strip category.


stratostar  (Student)

May 29, 2012, 5:23 AM
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Re: [riggerrob] "Nice" line-dump tandem photo [In reply to] Can't Post

It was my understanding, his claim is that now UPT is going stow less on their TDM dbags.


koppel  (F License)

Jun 1, 2012, 11:24 PM
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Re: [stratostar] "Nice" line-dump tandem photo [In reply to] Can't Post

I can't speak for UPT but I have seen a Sigma that contained a stowless bag in use for a long period without any apparent complications or issues. The bag was built utilizing tuck flaps for the line pocket and tangs and grommets to close the bag

In many ways some of the stowless bags offer better security against bag strip due to the inherent design.


JohnSherman  (D 2105)

Jun 2, 2012, 6:45 AM
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Re: [sundevil777] "Nice" line-dump tandem photo [In reply to] Can't Post

Quote:
Using such wide, therefore strong bands reinforces my opinion that it is a lousy philosophy to think that you want locking stows to be able to break so as to prevent a bag lock malfunction.

The wide stronger rubber bands did nothing to reduce line/bag strip (the same thing). Line dump is caused by the imbalance of the elements of the stow. See:http://www.jumpshack.com/...OW&SortBy=DATE_D

This was the beginning of our understanding. We don't get line/bag dump anymore.

Note: Bag "snatch" from the container can be as much as 20G's. What ever stow method you are using had better take that kind of loading to avoid the phenomenon.


nitrochute  (D License)

Jun 8, 2012, 6:06 PM
Post #15 of 20 (3031 views)
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Re: [DaVinciflies] "Nice" line-dump tandem photo [In reply to] Can't Post

ya also need to include " canopy slump ''


DaVinciflies

Jun 8, 2012, 6:23 PM
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Re: [nitrochute] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
ya also need to include " canopy slump ''

You have my attention! Explain please.


riggerrob  (D 14840)

Jun 11, 2012, 8:11 AM
Post #17 of 20 (2912 views)
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Re: [nitrochute] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
ya also need to include " canopy slump ''

........................................................................

"Canopy slump" was a common problem back when sleeves were fashionable.


rushmc  (No License)

Jun 14, 2012, 12:38 PM
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Re: [cpoxon] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
Here's another, in some, err, haze.

Did that one open???


sundevil777  (D License)

Jun 14, 2012, 2:12 PM
Post #19 of 20 (2657 views)
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Re: [DaVinciflies] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
In reply to:
ya also need to include " canopy slump ''

You have my attention! Explain please.

Here's a pic demonstrating how ugly things can look as the bag is lifted. I don't think the stretching of the bands is at all typical, wish I knew more about the circumstances of this, it is from a thread back in '07.
Attachments: Yuck.jpg (86.1 KB)


Premier skydiverek  (C 41769)

Jun 14, 2012, 2:44 PM
Post #20 of 20 (2647 views)
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Re: [sundevil777] "Nice" line-dump tandem photo [In reply to] Can't Post

In reply to:
Here's a pic demonstrating how ugly things can look as the bag is lifted. I don't think the stretching of the bands is at all typical, wish I knew more about the circumstances of this, it is from a thread back in '07.

And I believe this is Tandem Vector with the COLLAPSED drogue...!



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