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Any additional techniques for preventing line twist?

 

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arm900fj  (B License)

Jan 15, 2013, 11:28 AM
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Any additional techniques for preventing line twist? Can't Post

Assuming being stable and not rotating on main deployment, are there any other techniques that people use to minimize line twists?

Have only had a couple, but was just curious if there are any additional techniques regarding body position. Does slight forward motion help? Thanks in advance. Regards, Dave.


Premier Remster  (C License)

Jan 15, 2013, 11:42 AM
Post #2 of 43 (3154 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

Symmetrical packing, symmetrical body on deployment.


Zlew  (D 21616)

Jan 15, 2013, 11:46 AM
Post #3 of 43 (3144 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

good pilot chute (not worn out), and good throw
stow-less bag


DocPop  (C License)

Jan 15, 2013, 11:49 AM
Post #4 of 43 (3139 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

GEAR AND PACKING
- symmetrical packing and bagging
- an appropriate sized pilot chute in good condition
- equal tension on all linestows (or stowless bag)
- equal tension on legstraps (shrug and feel equal tnsion on shoulders.
- don't over tighten your chest-strap.

DURING OPENING
- good PC throw
- shoulders level with horizon
- feet and knees together as the opening sits you up
- don't look at the canopy
- don't fight the canopy - if it wants to turn, go with it


BrianSGermain  (D 11154)

Jan 15, 2013, 2:19 PM
Post #5 of 43 (3022 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

Be sure that the first three or four line stows to pull out are easily extracted. Double-stowing with a bite of more than 2.5 inches on the first several bites seems to be a mistake in most cases.

Also, make sure there is no less than TWO FEET of unstowed line above the risers. This allows the bag to get some speed before reaching line tension. The line stows are not usually in the middle of the bag, so low speed combined with asymmetrical loading can result in line twists.

Additionally, be sure that the unstowed line goes straight down the side of the rig, from the risers to the base of the rig, to prevent snagging on the bottom of the reserve container during slightly head up deployments.

-BSG-


JohnMitchell  (D 6462)

Jan 15, 2013, 2:40 PM
Post #6 of 43 (2998 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

Thanks for the tips. Smile

Do you recommend stowless bags too?


potatoman  (Student)

Jan 17, 2013, 4:37 AM
Post #7 of 43 (2762 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

Agree with Brian.

From the risers, straight to the bottom of the container, and then S fold the rest of the minimum 2 foot of line.
Check the type of bungees you use. Don't use different sizes. Meaning, 1st 2 bungees to extract, not so tight. Then semi tightfor the rest. Personal one this, but I like to double wrap the ones closing the d-bag, so basically on my config, the last 3 from the risers. You are most likely to get linetwist from the initial bungee releases, rather than the last ones.


BrianSGermain  (D 11154)

Jan 17, 2013, 10:05 AM
Post #8 of 43 (2704 views)
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Re: [JohnMitchell] Any additional techniques for preventing line twist? [In reply to] Can't Post

I love my UPT Vector "semi-stowless" bag. My openings have been fantastic since I switched to this bag. One linetwist in the past several years, and that was a packer that I had not used before.

If the parachute is held in the bag until full line extension, the opening is more likely to be a good one. The rest of the stowes do not seem to matter much. They provide a bit of organization, and that's it.

As far as double-stowing the closing stows with long rubber bands, it may prevent premature bag-dump, but you will go through rubber bands faster than single stowing the small rubber bands. Double-stowing beefy tube stows or similar on the closing bites, well that is called a significant potential for a bag lock.

Great thread!


(This post was edited by BrianSGermain on Jan 17, 2013, 10:09 AM)


Quagmirian  (A 110392)

Jan 17, 2013, 12:12 PM
Post #9 of 43 (2649 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
As far as double-stowing the closing stows with long rubber bands, it may prevent premature bag-dump, but you will go through rubber bands faster than single stowing the small rubber bands. Double-stowing beefy tube stows or similar on the closing bites, well that is called a significant potential for a bag lock.
Hey Brian, just wondering what you make of PD's take on this; I've been doing what they say.

http://youtu.be/4Nsca5add8g


cbassmnm  (C License)

Jan 17, 2013, 12:41 PM
Post #10 of 43 (2630 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

The old vector M-series manual says not to leave more than 15 inches of unstowed line between the bag and connector links. The newer manual says to leave no more than 15 to 20 inches. I guess because they have had lines entangle with container flaps before, but probably is rare.


BrianSGermain  (D 11154)

Jan 17, 2013, 1:11 PM
Post #11 of 43 (2607 views)
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Re: [cbassmnm] Any additional techniques for preventing line twist? [In reply to] Can't Post

Yes, some of the older Vectors with a "floating mid-flap" did have main lines entangle with the middle of the rig. Neither of these two instances were fatal or even injury related, however they were scary. That was several years ago, and as a UPT Vector pilot for many years, I am not concerned. They have addressed the possibility in newer models. I have tested up to six feet, and have extended the experiment to an entire DZ in Canada, Edmonton Skydive Centre, and they have reported nothing but improved openings.

I am not suggesting that you extend the unstowed length to six feet. I am merely working to prove the point that there is no increased danger associated with two or three feet of unstowed line above the risers. There is however, a very real and provable risk to stowing less than two feet. Linetwists can be severely unpleasant. Check out this video on YouTube:

"Parachute Malfunction Recovery"
http://youtu.be/-17AHJQQ8fA


(This post was edited by BrianSGermain on Jan 17, 2013, 1:13 PM)


faulk04  (D 32457)

Jan 17, 2013, 1:23 PM
Post #12 of 43 (2593 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
I love my UPT Vector "semi-stowless" bag. My openings have been fantastic since I switched to this bag. One linetwist in the past several years, and that was a packer that I had not used before.

If the parachute is held in the bag until full line extension, the opening is more likely to be a good one. The rest of the stowes do not seem to matter much. They provide a bit of organization, and that's it.

As far as double-stowing the closing stows with long rubber bands, it may prevent premature bag-dump, but you will go through rubber bands faster than single stowing the small rubber bands. Double-stowing beefy tube stows or similar on the closing bites, well that is called a significant potential for a bag lock.

Great thread!


with the stowless bag do you still leave the 2 feet of excess from the risers out of the pouch on the bag? Or does that not matter with this bag?


BrianSGermain  (D 11154)

Jan 17, 2013, 1:40 PM
Post #13 of 43 (2579 views)
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Re: [faulk04] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
In reply to:
I love my UPT Vector "semi-stowless" bag. My openings have been fantastic since I switched to this bag. One linetwist in the past several years, and that was a packer that I had not used before.

If the parachute is held in the bag until full line extension, the opening is more likely to be a good one. The rest of the stowes do not seem to matter much. They provide a bit of organization, and that's it.

As far as double-stowing the closing stows with long rubber bands, it may prevent premature bag-dump, but you will go through rubber bands faster than single stowing the small rubber bands. Double-stowing beefy tube stows or similar on the closing bites, well that is called a significant potential for a bag lock.

Great thread!


with the stowless bag do you still leave the 2 feet of excess from the risers out of the pouch on the bag? Or does that not matter with this bag?

Really good question. As far as I can tell, leaving less than two feet on the UPT semi-stowless bag does not se to change the openings. I am still playing with that. Anyone else care to weigh in?


faulk04  (D 32457)

Jan 17, 2013, 1:50 PM
Post #14 of 43 (2567 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

I don't do it on either of my rigs with the semi stowless bag... I go pretty much up to the risers and any excess that is needed comes out when I take the dbag and place it into my container. I've put about 300 jumps doing this method and haven't had any problems so far.


cbassmnm  (C License)

Jan 17, 2013, 1:53 PM
Post #15 of 43 (2565 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

Thanks for clearing that up for me, I have seen pics of the old vectors with the middle flap. I always thought that the lines had entangled with one of the side closing flaps... glad to know this now!
I was just stating what the manual said about unstowed line length, they must have put it because they believe they get the best results from it.
I dont doubt your method a bit... you have been jumping longer than I have been alive. Ill probably start leaving a little more unstowed line now after this forum.
I actually have already seen your video where you do the high alt hnp and fight the line twists for a long time, but didnt mind watching it again...impressive! Plus im reading the canopy and its pilot now as well. Thanks for your info, great talking to you.


pchapman  (D 1014)

Jan 17, 2013, 1:58 PM
Post #16 of 43 (2559 views)
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Re: [faulk04] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
I don't do it on either of my rigs with the semi stowless bag... I go pretty much up to the risers

Ditto for me because the lines come out the centre. Seems to work but 1000 jumps on it is still a drop in the statistical bucket. Had a few minor twists (360 or less) on the crossbraced canopy but no big spinups.


arm900fj  (B License)

Jan 17, 2013, 2:03 PM
Post #17 of 43 (2554 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

Does having a little forward motion or slight heads down postion on deployment help or are there any other body position tips other than what has been discussed?.. stable, symetrical, etc.


BrianSGermain  (D 11154)

Jan 17, 2013, 2:21 PM
Post #18 of 43 (2537 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
Does having a little forward motion or slight heads down postion on deployment help or are there any other body position tips other than what has been discussed?.. stable, symetrical, etc.

Although head-down attitude seems imprudent on deployment, I do notice more on-heading openings when I have a bit of forward coast left over from my tracking. This is not high decent rate, mind you, just forward movement. It seems to give the canopy a place to go. If anyone else does this as well, please chime in.


Deyan  (D 322)

Jan 17, 2013, 2:39 PM
Post #19 of 43 (2519 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
I am not suggesting that you extend the unstowed length to six feet. I am merely working to prove the point that there is no increased danger associated with two or three feet of unstowed line above the risers. There is however, a very real and provable risk to stowing less than two feet.

I couldn't disagree more.
Take a slow motion footage of the deployment. Look at the free lines right after the d-bag leave the container . No tension on the lines inside the burble area is a really bad idea. I agree that the opening feels better with longer unstowed lines, but ( IMO )the risk of a line half hitching behind your side flap stiffener ( or pin cover, or... whatever is there ) is not worth.

Before I started testing stow less and semi stow less bags I've had about 300 + jumps without line twist. In all those jumps the free stowed lines were 40 cm or less. Before that I've had many twists using whatever rubber bands I could find, PC's not sized for the weight of the bag etc. The key is a good PC , rubber bands located in the middle of the bag and equal line stow tension.

Get those things right and you don't have to use the two,three or six feet unstowed lines "magic".


BrianSGermain  (D 11154)

Jan 17, 2013, 4:33 PM
Post #20 of 43 (2465 views)
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Re: [Deyan] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
In reply to:
I am not suggesting that you extend the unstowed length to six feet. I am merely working to prove the point that there is no increased danger associated with two or three feet of unstowed line above the risers. There is however, a very real and provable risk to stowing less than two feet.

I couldn't disagree more.
Take a slow motion footage of the deployment. Look at the free lines right after the d-bag leave the container . No tension on the lines inside the burble area is a really bad idea. I agree that the opening feels better with longer unstowed lines, but ( IMO )the risk of a line half hitching behind your side flap stiffener ( or pin cover, or... whatever is there ) is not worth.

Before I started testing stow less and semi stow less bags I've had about 300 + jumps without line twist. In all those jumps the free stowed lines were 40 cm or less. Before that I've had many twists using whatever rubber bands I could find, PC's not sized for the weight of the bag etc. The key is a good PC , rubber bands located in the middle of the bag and equal line stow tension.

Get those things right and you don't have to use the two,three or six feet unstowed lines "magic".

You are free to disagree with my logic, but I am also free to lovingly fire back. The slow motion video of deployment is not in an of itself a reason to change packing methods. There is chaos in every phase of the deployment, but this is not a reason to take an alarmist position. If you can prove to me that significant freedom is correlated with horse-shoe entanglements with the rig, I will believe you. However, the data that I have seen does not suggest this at all.

I, like you, have arrived at the conclusion that a semi-stowless bag is the way to go for me. I have also started to leave only about a foot an a half of free line (similar to your 40 cm). So, regardless of what got us there, we seem to have arrived at the same conclusion.

Is there really an argument at all?

I love skydivers.
Especially ones who think.


JohnSherman  (D 2105)

Jan 17, 2013, 5:47 PM
Post #21 of 43 (2426 views)
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Re: [arm900fj] Any additional techniques for preventing line twist? [In reply to] Can't Post

Quote:
Assuming being stable and not rotating on main deployment, are there any other techniques that people use to minimize line twists?

Have only had a couple, but was just curious if there are any additional techniques regarding body position. Does slight forward motion help? Thanks in advance. Regards, Dave.

"Sit up and Dump". Keep your shoulders level to the ground as you sit up and don't look over you shoulder to check or clear the pilot chute. Dropping a shoulder will cause the air flow to come off your back in a spiral. This will cause the bag to spin. If you need to check or clear your pilot chute look straight up over your head, this will put you in a sitting position ready to accept the opening in your saddle and get the air flowing up over your back. This also locates you feet so thay are not near the direction of deployment.


Divalent  (C 40494)

Jan 17, 2013, 5:56 PM
Post #22 of 43 (2421 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
... I, like you, have arrived at the conclusion that a semi-stowless bag is the way to go for me. I have also started to leave only about a foot an a half of free line (similar to your 40 cm). So, regardless of what got us there, we seem to have arrived at the same conclusion.

Is there really an argument at all?

But in your post above, you state "Also, make sure there is no less than TWO FEET of unstowed line above the risers."

Since 2 feet = ~61 cm, (and 40 cm is absolutely less than 61 cm), I'm not seeing the agreement between the two of you.

I'm interested in the topic, and appreciate everyone who is weighing in on it.


Skydivesg  (D 10938)

Jan 17, 2013, 6:52 PM
Post #23 of 43 (2396 views)
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Re: [BrianSGermain] Any additional techniques for preventing line twist? [In reply to] Can't Post


Really good question. As far as I can tell, leaving less than two feet on the UPT semi-stowless bag does not se to change the openings. I am still playing with that. Anyone else care to weigh in?
I've been using the UPT semi-stowless bag since it was a proto type. I have about 1200 jumps on it and love it. It has made my openings much more predictable.

I use tandem bands for my locking stows and double wrap them with no more than 1.5 inches of line bite.

I love the fact that I don't have to try to measure as I'm stowing my lines to get just the right amount left over.

I always sucked at that and either had too much or not enough excess.

Now I stack the lines all the way to my risers and then pull out just enough to run the risers and lines down to the corners of my pack tray. It's awesome. I'm thrilled with that bag and with the openings that I know it has helped give me.

Line twists are pretty much a thing of the past.

.


Premier DSE  (D 29060)

Jan 17, 2013, 8:22 PM
Post #24 of 43 (2361 views)
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Re: [Skydivesg] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:

Now I stack the lines all the way to my risers and then pull out just enough to run the risers and lines down to the corners of my pack tray. It's awesome. I'm thrilled with that bag and with the openings that I know it has helped give me.

Line twists are pretty much a thing of the past.

.

I do the same. Zero excess. Works great with the WS and non-WS jumps.


airtwardo  (D License)

Jan 17, 2013, 9:19 PM
Post #25 of 43 (2334 views)
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Re: [Deyan] Any additional techniques for preventing line twist? [In reply to] Can't Post

In reply to:
In reply to:
I am not suggesting that you extend the unstowed length to six feet. I am merely working to prove the point that there is no increased danger associated with two or three feet of unstowed line above the risers. There is however, a very real and provable risk to stowing less than two feet.

I couldn't disagree more.
Take a slow motion footage of the deployment. Look at the free lines right after the d-bag leave the container . No tension on the lines inside the burble area is a really bad idea. I agree that the opening feels better with longer unstowed lines, but ( IMO )the risk of a line half hitching behind your side flap stiffener ( or pin cover, or... whatever is there ) is not worth.

Before I started testing stow less and semi stow less bags I've had about 300 + jumps without line twist. In all those jumps the free stowed lines were 40 cm or less. Before that I've had many twists using whatever rubber bands I could find, PC's not sized for the weight of the bag etc. The key is a good PC , rubber bands located in the middle of the bag and equal line stow tension.

Get those things right and you don't have to use the two,three or six feet unstowed lines "magic".

In the F1-11 days I use to flat-pack & stow the lines up to the links, line twist was rare & not critical given the size & performance of the canopy.

With my 1st X-brace canopy I was told to PRO pack only & leave 16 to 18 inches unstowed, line twist was still somewhat rare - but certainly more of a problem when it did occur.

I got to thinkin'...back in the 70's I had several canopies that used a 'Raeper' which is like a 'Frap-Strap' but with room for more than just one stow...instead of a bag.

The Raeper was sewn to the outside of the right endcell, the idea basically was to 'shake & flake' the canopy like step 1 of a PRO pack. The Raeper was a flap of para-pack that went around the base of the cocoon and was held shut with a couple of line stows... rubber-bands through grommets like on a bag.

The lines were then free-stowed into the container, just coiling them up against the backpad, the 'cocooned' canopy was S folded on top of the lines and the container closed as is done today. You could literally pack in 2 minutes before walking in.

I absolutely NEVER had a line twist of any kind using a raeper, openings were crisp but not hard...I believe the lack of a bag 'staging' the lines - getting the bag rocking & twisting right after snatch was the reason.

A few years back I started leaving between 2 to 2.5 feet unstowed on my current canopies in hope it would have the same basic effect, and it certainly seems to...have not had a line twist since I started doing that.
Attachments: Launch.JPG (47.5 KB)
  two feet.JPG (46.0 KB)
  no twist.JPG (52.4 KB)
  Cleared the bag.JPG (53.5 KB)


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