Forums: Skydiving Disciplines: Swooping and Canopy Control:
JVX - loose lines on opening??

 

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pressuremedia  (D 11382)

Oct 10, 2007, 8:36 PM
Post #1 of 41 (3629 views)
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JVX - loose lines on opening?? Can't Post

anyone else get loose lines jumping around on opening? I have messed around with my JVX a bit but at present have a regular lineset and slider. At the moment I have a mix of tight and loose lines on opening. Does anyone else get this?


RickyGood  (D 590)

Oct 11, 2007, 5:44 PM
Post #2 of 41 (3443 views)
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Re: [pressuremedia] JVX - loose lines on opening?? [In reply to] Can't Post

  
Hey whats up Jim.
Where are you jumping now, you missing the Zone?? :)
I heard you had some problems with your jvx openings.
I've had 3 jvx's and they all opened really well, soft but always with tension on the lines.
But, I had an 89vx with jvx lineset and the C's and D's would flap around during opening, I had two chops because of tension knots on it.
Is it the same lines that are flapping on your wing?


pressuremedia  (D 11382)

Oct 11, 2007, 8:04 PM
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Re: [RickyGood] JVX - loose lines on opening?? [In reply to] Can't Post

doing well Ricky. will pm you with a lot more.

Jumping a zp 90JVX
Yes, these lines are flapping around. Changed slider a few times and now not getting the tension knots (yet - a few before) but a lot more flapping lines.

All of your JVX's opened without flapping lines???

Anyone with a JVX and flapping lines?


rhys  (D 95)

Oct 11, 2007, 8:38 PM
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Re: [pressuremedia] JVX - loose lines on opening?? [In reply to] Can't Post

Hi Jim,

I havn't noticed any lines flapping aroud on mine!

To be honest I haven't really been looking though. I have a look this weekend.

Hows the careere change going?

charge on

rhyso


hparrish  (D 25090)

Oct 13, 2007, 9:51 AM
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Re: [pressuremedia] JVX - loose lines on opening?? [In reply to] Can't Post

How many jumps do you have on your JVX?

You need to change your lineset around 250 - 400 jumps. That's one of the reasons they come with a spare line set.

If you're below those numbers, you have a problem.


RMURRAY

Oct 13, 2007, 2:35 PM
Post #6 of 41 (3269 views)
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Re: [hparrish] JVX - loose lines on opening?? [In reply to] Can't Post

In reply to:
How many jumps do you have on your JVX?

You need to change your lineset around 250 - 400 jumps. That's one of the reasons they come with a spare line set.

If you're below those numbers, you have a problem.

is it the original lineset or was it relined....maybe the reline job is the problem. I would talk directly to Jim S about it.

rm


(This post was edited by RMURRAY on Oct 13, 2007, 2:37 PM)


diablopilot  (D License)

Oct 14, 2007, 4:31 PM
Post #7 of 41 (3173 views)
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Re: [hparrish] JVX - loose lines on opening?? [In reply to] Can't Post

In reply to:
How many jumps do you have on your JVX?

You need to change your lineset around 250 - 400 jumps. That's one of the reasons they come with a spare line set.

If you're below those numbers, you have a problem.
That makes no sense what so ever. How is changing to the exact same lineset going to change the amount of slack line he's experiencing? It's HMA, it changes less than 1/2" in a 1000 jumps.


hparrish  (D 25090)

Oct 14, 2007, 8:24 PM
Post #8 of 41 (3152 views)
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Re: [diablopilot] JVX - loose lines on opening?? [In reply to] Can't Post

I'll yield to your experience with JVX's and their Trim Sets. I assume you jump them and understand every aspect of them? But hey thanks for the Flame.

I was not stating that this alone was his problem, but he should take jump numbers into consideration if he has more than 400 jumps on a JVX line set.

It could be that he simply has a poorly trimmed line set, and should take that up with Jim if less than 250 jumps.

You can't assume that all HMA lines are constructed the same way and wear at the same rate. You also cannot say that HMA will only wear up to a 1/2 inch in 1000 jumps. You can't state that because many things alone or in combination contribute to line wear and shrinkage or taking a line set out of trim.

We don't know if he has a stock slider, brass or steel slider gromets, or even a knick in one of his grommets. He could have shortened his control lines, or he could just have a bad line set. We don't know.


(This post was edited by hparrish on Oct 14, 2007, 8:37 PM)


frost  (D 25011)

Oct 15, 2007, 6:30 AM
Post #9 of 41 (3100 views)
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Re: [hparrish] JVX - loose lines on opening?? [In reply to] Can't Post

Harry, it has nothing to do with JVX or any other canopy. It's the suggestion that the opening issues are due to worn or "out of trim" HMA lineset that's incorrect. HMA offers some of the best dimensional stability compared to any other line type, it doesnt shrink or go out of trim, at least not sooner then the lines break due to wear and tear :) That is one of the reasons it has become a popular choice for high performance wings.


hparrish  (D 25090)

Oct 15, 2007, 8:04 AM
Post #10 of 41 (3071 views)
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Re: [frost] JVX - loose lines on opening?? [In reply to] Can't Post

Yes I know what's adverstised with regard to HMA, and agree with it for the most part. I agree that HMA is more likely to break than streatch when they are worn, but I don't believe that HMA lines never go out of trim.

Even 1/2 inch out of Trim on A-D lines on a JVX can affect performance. Probably not so much on the control lines.

The OP did not specify how loose his lines were. But I'd agree that if they were significantly loose (4-6") then it's probably a line trim issue or a Control Line setting issue.


pressuremedia  (D 11382)

Oct 16, 2007, 3:17 PM
Post #11 of 41 (2955 views)
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Re: [RMURRAY] JVX - loose lines on opening?? [In reply to] Can't Post

they are vectran lines not HMA. The JVX has 3-400 jumps on. The lineset has not been changed. The JVX was one of the first ones and came with the four flap slider. Since then the brake lines have been changed according to an update and the slider is the correct size with no flaps. Line trim has been checked and does not seem to be out at all.


mmm_peanuts  (D 29215)

Feb 13, 2011, 1:36 PM
Post #12 of 41 (2486 views)
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Re: [pressuremedia] JVX - loose lines on opening?? [In reply to] Can't Post

I too have a zp jvx90 with vectran lines and am experiencing the same loose lines during opening; Specifically it is most drastic just before the slider starts to move down. My lines have around 150 jumps, and I have videos showing this on essentially every opening. When these lines decide to not knot up (happend twice in 150 jumps), the openings are simply amazing; non seaking snivel with center cell inflation spreading out to the endcells, easily staying on heading. This canopy is DOM feb. 2006.

I can post videos with frames showing rogue loose lines forming randomly during inflation upon request.


RMURRAY

Feb 14, 2011, 2:32 PM
Post #13 of 41 (2367 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

In reply to:
Specifically it is most drastic just before the slider starts to move down

I have not noticed this but wonder if it is the slider not moving off the stops "cleanly". I have had a bunch of wild rides which seem to start right at that point. Maybe MEL could comment?


(This post was edited by RMURRAY on Feb 14, 2011, 2:33 PM)


stayhigh  (F 111)

Feb 15, 2011, 6:02 AM
Post #14 of 41 (2294 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

post video frame please.


mmm_peanuts  (D 29215)

Feb 16, 2011, 8:21 PM
Post #15 of 41 (2152 views)
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Re: [stayhigh] JVX - loose lines on opening?? [In reply to] Can't Post

Here is a sample of of 6 openings. Despite what the lines are doing, all of these opened beautifully soft and on heading.

I apologize for the lack of quality of these photos. Just switched to mac, and imovie is refusing to work with anything that touched sony vegas. Screenshots are the best that I could get. Btw I am a very neat packer, and initial snivels show no slack lines on any of these openings.


(This post was edited by mmm_peanuts on Feb 16, 2011, 8:22 PM)
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AggieDave  (D License)

Feb 16, 2011, 8:23 PM
Post #16 of 41 (2148 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

It looks like the outside lines, the ones that aren't under tension because that part of the canopy is still inflating.


mmm_peanuts  (D 29215)

Feb 16, 2011, 8:30 PM
Post #17 of 41 (2145 views)
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Re: [AggieDave] JVX - loose lines on opening?? [In reply to] Can't Post

Thats what I thought. Is anyone seeing this on other hp canopies, or is this specifically jvx? I love this canopy, and would hate to change due to increased malfunction rate; my only cutaway was a tension knot after an ideal snivel on this canopy. I also only noticed this after reviewing videos, and have never seen it during jumps.


(This post was edited by mmm_peanuts on Feb 16, 2011, 8:34 PM)


raymod2  (D 25630)

Feb 16, 2011, 9:16 PM
Post #18 of 41 (2135 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

For what it's worth I have about 1000 jumps on my JVX 90 and I have never had a malfunction on it. I don't watch my openings and I have no video of them.


flow  (D 3019)

Feb 17, 2011, 6:23 AM
Post #19 of 41 (2086 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

I've had that happen both on my Velocity and (J)VX. Only on vectran lines though, not on HMA, or it's just not as visible to be seen on video.


rem

Feb 17, 2011, 10:09 AM
Post #20 of 41 (2056 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

on my FX, 94, 89 and 84, ten years old and a few thousand jumps each, the sliders are "perforated" at the point where these outside-lines seem rub and burn.


masterrigger1  (D 14167)

Feb 18, 2011, 4:10 PM
Post #21 of 41 (1936 views)
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Re: [RMURRAY] JVX - loose lines on opening?? [In reply to] Can't Post

Quote:
I have not noticed this but wonder if it is the slider not moving off the stops "cleanly". I have had a bunch of wild rides which seem to start right at that point. Maybe MEL could comment?

Sorry, just saw this post! I am still in Reno had just had a moment to log on....


The lines are loose because of exactlt what Aggie spoke of. The canopy has not yet pressurized fully and extended the line.

With Technora this becomes an issue as the slider is trying to come downward, causing excess BELOW the slider of the not yet extended lines. Technora has a lot of "grip" in reference to the slider.


BS,
MEL


mmm_peanuts  (D 29215)

Feb 18, 2011, 9:04 PM
Post #22 of 41 (1917 views)
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Re: [masterrigger1] JVX - loose lines on opening?? [In reply to] Can't Post

These lines are vectran.


(This post was edited by mmm_peanuts on Feb 18, 2011, 9:16 PM)


masterrigger1  (D 14167)

Feb 21, 2011, 3:58 AM
Post #23 of 41 (1843 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

Quote:
These lines are vectran

Vectran would usually act the same as it is not as smooth as Spectra.

Even more so if it is a little worn. As it wears, it becomes more like Technora as far as grip in relation to the slider grommets.

A high aspect ratio canopy is short on chord and long on wing span.

So during inflation is is going to inflate from the center out during a normal opening (hopefully).

The only way to reduce the delay the inflation of the end cells is to open up the crossports WHICH is NOT recommended.

Cheers,
MEL


mmm_peanuts  (D 29215)

Feb 21, 2011, 2:18 PM
Post #24 of 41 (1803 views)
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Re: [masterrigger1] JVX - loose lines on opening?? [In reply to] Can't Post

Is there any line type you would recommend to minimize this problem? These lines are still quite new to feel and appearance, with little wear to the lines and grommets.


masterrigger1  (D 14167)

Feb 22, 2011, 4:46 AM
Post #25 of 41 (1767 views)
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Re: [mmm_peanuts] JVX - loose lines on opening?? [In reply to] Can't Post

Quote:
Is there any line type you would recommend to minimize this problem? These lines are still quite new to feel and appearance, with little wear to the lines and grommets.

No, not really.

I would suggest looking at how you pack and maybe try something a little different to speed up the end cells inflation process.

Cheers,
MEL


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