Diagnose this opening problem!

[pilotdave 0]

Any ideas what might cause a stabilizer or end cell to hold the slider up? See attached pics... this has been happening for months now on occasion. It's not something the canopy has always done. I have probably at least 1400 jumps on this canopy. On some openings, it looks pretty much like end cell closure, but one corner of the canopy will hold the slider up. Either on it's own or with a pump of the rear risers, the canopy will pop open and the slider will come down.

The canopy has been inspected by multiple riggers. There doesn't seem to be anything physically wrong with it. Have not had the trim checked... it is most likely a bit out of trim since the lines were replaced a few years ago (2nd lineset). But the lines appear to be in good shape.

The slider stops on the canopy are in place. The only issue found was some stitching on the edge of the slider had come undone. A rigger thought that maybe that side of the slider was inflating a little bit and getting more drag, shoving that side into the slider stops on opening. He fixed the stitching, but the problem continues every now and then.

Hard to believe it's a packing issue since it has happened with multiple packers and I've packed the canopy so many times myself.

It usually seems to happen with the left front corner of the canopy/slider. But I have had it happen on the right side too.

Any ideas? Again, it's been inspected (for this particular issue) by multiple very experienced riggers. It's nothing obvious. It's also not a really big deal since it has always come out and it's fairly tame while happening. But I would like to figure out what's going on.

Edit: to be clear, those are four different openings on four different dates.

Dave

[masterrigger1 2]

That canopy is out of trim!

...and the intersect point of the a-b looks like they are catching the slider and holding it there momentarily.

Try longer risers to flatten the canopy oout some and I bet it will not do it as bad.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[erdnarob 1]

This doesn't look like a line over.
It seems that some lines are caught together at the rear left side grommet of the slider. I would say the problem comes from a tension knot between two lines (one from the rear and one from the front) which keeps the slider (rear left side) in the high position. Prevention of that. Have the right size of of rubber bands. You probably got a partial lines dump on the left side.

Learn from others mistakes, you will never live long enough to make them all.

[ufk22 32]

Have you talked to PD?
They say the most common cause of tension knots (don't know if that is part of the problem) is twists in microlines. I'd walk every line from the canopy back to the risers to check for any twists. They're easy to take out of steering lines, require disconnecting to get out of the other lines.
Have you checked the slider size against what PD recommends? Some of the Sabres were sometimes hard openers when new, and I've known people to put on oversize sliders to soften them up.
Years ago, Charley Mullins was test jumping a really small prototype canopy at our boogie, trying different size sliders. One was big enough that it wouldn't let the canopy inflate and he had to chop it.

This is the paradox of skydiving. We do something very dangerous, expose ourselves to a totally unnecesary risk, and then spend our time trying to make it safer.

[masterrigger1 2]

Quote

I would say the problem comes from a tension knot between two lines (one from the rear and one from the front) which keeps the slider (rear left side) in the high position.

There is no evidence of a tension knot there....look at the pictures!

The reason the nose is folded under is that:
1. The lengths of the A-B's on the outside (PD numbering A5) are too short. Short enough to make the Nose roll under instead of inflating and going to where they need to be.

2. The second problem is that the lowers have shrunk so much that the tail on the outside is pulled into a very deep brake setting, thus not allowing those outside cells to inflate.
The crossporting usually will make the ends cells inflate sooner or later. The problem is that one side usually inflates before the other causing line twists, spins, and on occasion, cutaways!

I've seen this stuff hunderds of times...you just gotta love Spectra!

Change nothing but the lines and problem fixed.

Cheers,
MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[JohnDeere 0]

I had the same happen to my Sabre 2(just not as bad). Outside A lines to short. My rigger showed me how to notice (mine is 150 so may be diff?) that they were to short. When packing, canopy over sholder, that shorter A line whould pull fabric through the slider groment.

Nothing opens like a Deere!

You ignorant fool! Checks are for workers!

[pilotdave 0]

Thanks for the info! Guess it's time for another reline. This beats the couple of hard openings I got before to let me know it was time for a reline. Not sure if I've had even a single hard or even brisk opening since it was relined in 2006 or so.

Dave

[rushmc 18]

Quote

Quote

I would say the problem comes from a tension knot between two lines (one from the rear and one from the front) which keeps the slider (rear left side) in the high position.

There is no evidence of a tension knot there....look at the pictures!

The reason the nose is folded under is that:
1. The lengths of the A-B's on the outside (PD numbering A5) are too short. Short enough to make the Nose roll under instead of inflating and going to where they need to be.

2. The second problem is that the lowers have shrunk so much that the tail on the outside is pulled into a very deep brake setting, thus not allowing those outside cells to inflate.
The crossporting usually will make the ends cells inflate sooner or later. The problem is that one side usually inflates before the other causing line twists, spins, and on occasion, cutaways!

I've seen this stuff hunderds of times...you just gotta love Spectra!

Change nothing but the lines and problem fixed.

Cheers,
MEL

Wow, what a very clearly written explination!!

We were having some issues with some tandems earlier this year. One of our video guys (Doc John) got a GREAT video of one of the suspect openings and then pulled a (another) great still out of the video. Sent the info to the manufacturer and with in 10 minutes I had an explanation nearly duplicating your post.

The still is going to be used by the manufacturer as well as maybe the video.

Anyway, more for kudos to the clarity of your explanation. That can be hard to do

"America will never be destroyed from the outside,
if we falter and lose our freedoms,
it will be because we destroyed ourselves."
Abraham Lincoln

[piisfish 135]

Quote

since it was relined in 2006 or so.

How many jumps on the lineset ?

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[erdnarob 1]

Thanks for the clear explanation, I was assuming the lines had the right length. Unfortunately, people posting their problem not always give us important info like the no. of jumps on the canopy or else.

Learn from others mistakes, you will never live long enough to make them all.

[riggerrob 558]

Yes, I have seen that problem on SET 400 - tandem mains - if the A lines are allowed to shrink more than 4 inches.
A line attachment points get sucked into the slider grommets, Openings get ugly and the A line attachment points fray so badly they need to be replaced.
If you stick with Strong Enterprises' recommendations and reline after 300 jumps - or when A lines get 3 inches out of trim - then you never have to deal with frayed A line attachment points.

IOW If you try to save money by delaying re-lining canopies, you spend the money somewhere else!
Tee!
Hee!

[irishrigger 31]

i have to agree with master rigger,the line trim seems to be way out.so its not suprising if yoou where getting some funky opening on it.
you might also check the grommets on your slider to see if there is any sharp edges or burrs on them.i had that happen to me on my canopy last year.
so a reline and possiby a new slider should solve that problem very quick.
also send those pics to PD,but i think they will give you the same answer.
cherrio

rodger

[douwanto 22]

I had a similar problem a few years back on a nova. It looks like the stabilizer line tabs are getting pulled threw the grommet catching the lines in the process. try flaking the stabilizer out and pulling the slider off the tabs a little.



I know it will go back up on opening but the canopy will separate some before it does. This helped my openings.

Your grommets may be worn or distorted. Some canopy have slider stops at the tabs to keep this from happening. It wont matter if the canopy is in trim if it goes far enough threw the grommet to pinch some lines and impede the sliders decent.

Uncle/GrandPapa Whit
Unico Rodriguez # 245
Muff Brother # 2421

[hookitt 0]

No, don't do that. I don't recall how the Nova was configured... other than poorly. There are stops on the canopy in the pictures and under no circumstances should the slider be pulled away from the stops prior to closeing the D-Bag. That's exactly how really fast openings occur.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[douwanto 22]

so 1 inch will make the canopy open extremely fast????
Most times the slider will move that far off the stop during packing. In picture 4 it looks like a peice of the stablizer is threw the grommet. I enlarged the picture to be sure and it is there. May not be a problem.

Uncle/GrandPapa Whit
Unico Rodriguez # 245
Muff Brother # 2421

[billvon 2,400]

>so 1 inch will make the canopy open extremely fast????

Yes, if it stays there! What saves people sometimes is that the wind hits the slider first and forces it up against the canopy before the canopy has time to try to inflate on its own. But if it doesn't, or if the slider gets further away than the wind can get it to move, openings can be very, very hard.

[airnutt 8]

if jumping a canopy with spectra lines check outer a & c lines for shrinkage and then check steering and readjust to factory length