twisty sigma drogues

[tsalnukt 1]

We just put 2 brand new sigma drogues into service and they keep twisting up in drogue fall to the point that it won't collapse at opening.

Has anyone experienced this?? Anyone have any idea what could be causing it (besides possibly being unsymmetrical). Anyone know of any easy fixes??

I'm calling the UPT tomorrow but I figured I would ask 'the people' first. Thanks

[skydivekc 0]

Yes, they are calling it a "spinning drogue".... I have a couple that did this and UPT will send you out a replacement.

[Kimblair13 0]

Yup...just send them back. Sucks to realize you have a bad one when you get cracked on opening.

[parachutist 1]

tsalnukt

Anyone know of any easy fixes??

We had a batch of 4 of these spinners recently. I called UPT and was told of some new cutting machine messing up the parts, causing the panels to stretch unevenly. Maybe that happened, but I don't believe that caused the crazy tight spinning for our drogues. We sent the first one in for replacement, then decided to test the others before exchanging them.

We measured the kill lines and they were about 3.5" shorter than they should be on these new drogues. I hooked each of our new bridles onto a peg, pulled with about 20 lbs of force, and the larks head would hit the grommet. I added a 3.5" extension to each kill line, and they work now (we still get some twists, but now it's a typical amount).

It's an easy test at least, to see of your kill lines are too short.

Chris

[michaelted57 1]

That's a very easy test and a great idea (which should probably be done anyway). Thanks!

If it comes easy, I'm automatically suspicious

[RIGGER 0]

Hi

the pull force should be 10 lb. & the knot should be set at 1 1/2" above the bridle top grommet.

Safe Jump !!!

[parachutist 1]

RIGGER

Hi

the pull force should be 10 lb. & the knot should be set at 1 1/2" above the bridle top grommet.

Safe Jump !!!

I disagree on that. UPT wrote the original instructions at a time when their bridles were built of Kevlar. It says "Apply equal tension (at least 10 pounds) against the drogue bridle and kill line, with each hand."

Kevlar stretches about as much at 10 lbs as it would if you applied 30 lbs. Currently UPT makes the bridles of TY-12, which stretches a lot more than Kevlar. I believe 40-50 lbs of pressure should be used when sizing for the kill line. Do you believe that during droguefall there is only 10 lbs of pressure on that bridle? Do you think it's ok for the lark's head knot to hit the grommet?
(edited)

IMO, UPT was either not observant enough to realize the difference between Kevlar and TY-12, or they were just too lazy to create an addendum for the Sigma manual.

blue skies,
Chris

[RIGGER 0]

Hi

Thanks for that.

I know the points you point on : Kevlat & Nylon - you didn't point on the
drogue bridle material.

The larks should not impact the grommet at any time but that could happaned when the spectra 1000 get shorter with use.
The kill line should be calibrated at about 100 jumps or sooner.

UPT went back to Kevlar, the Ty.12 have some issues.

Cheers

[parachutist 1]

RIGGER

UPT went back to Kevlar, the Ty.12 have some issues.

Cheers

UPT reminds me of a Katy Perry song... changing their minds faster than a girl changes clothes. I recently had an e-mail discussion with UPT about their TY-12 bridles. The last message was Jun 19... about 5 weeks ago. UPT was adamant about their 1-piece TY-12 bridles being the solution to all problems.

I was complaining about the 1-piece version because I was saying the disc attachment area was going to wear out long before the drogue envelope. They told me the Ty-12 1-piece was here to stay.

Are they definitely shipping Kevlar again?

regards,
Chris

[RIGGER 0]

Hi Chris

Thanks.

Yes, they went back to the Kevlar & I heard about the one piece long bridle - you are right, the disc area always has
wear issues with the spectra webbing/tape & the spectra safety lines.

Let's see it in action.

Cheers

Shlomo

[RIGGER 0]

Hi

I just got few new Sigma 54" drogues with Ty.12 one piece bridle.

Lets see how that will work.

In the past I asked why not to attached the bridle to the drogue canopy with slinks so if the bridle wear out before the drogue canopy it could be easy replaced. (that was on the Atom / Galaxy tandem systems from PdF but they use SS Rapide links)

Time will tell on the new UPT's drogues.

Cheers

[Scrumpot 1]

Is replacement ease, really affected dependent upon whether you're attaching via rapide, versus slink? Not that this would (conceivably) have any influence on the OP subject, but just where you mention it - I am now curious, as I cannot envision what would make using one over the other, materially more difficult (or not) to replace.

coitus non circum - Moab Stone