Sigma Reserve Openings

[Kimblair13 0]

Just curious what peoples experience with Sigma Reserve openings are. I'm seeing some serious stalling, surging scariness and wondering what's up. Have been told "they are supposed to open like that in case of a terminal ride". Is this true. I'm not talking just a little stall or surge either. Pretty bad and continues even after breaks are un-stowed for a bit. I've seen lots of Sigma reserve rides and have had my fair share and am just now seeing this in one place. Anyone?

[indyz 1]

My only Sigma reserve ride opened in a stall (bucking and surging, not collapsing or bow-tieing) and stayed that way until I released the brakes. I mentioned it when I landed and was told by a Sigma I/E that those kind of openings are normal and I should have been told to expect it during my rating course.

Since there is only one possible way to set the brakes on the VTC-III (VR-360) reserve, which is also the only reserve that should ever be assembled into a Sigma, I'm not sure where a difference in flight characteristics with the brakes stowed would come from, other than a difference in suspended weight.

[diablopilot 2]

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which is also the only reserve that should ever be assembled into a Sigma,

On what basis do you make that decision?

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You're not as good as you think you are. Seriously.

[pchapman 280]

I'm interested in hearing replies to this too.

I've only had one Sigma reserve ride but I'm guessing the difference in openings depend on a lot of things: chance, speed, position on opening, perhaps suspended weight, and the jumper's awareness.

Position on opening:
If the tandem pair are opening off the vertical, maybe flung out to the side from a spin and especially using a Skyhook, then the canopy won't be in a stable above-the-jumpers position to start with. A little bit of surging then gets the whole edge-of-stall and recover motion going.

Do people find it is worse on higher speed openings? I could see that happening.

Jumper's familiarity might have a small role too, as to what they report. I occasionally jumped a Parafoil that did the surging thing on opening, but I barely noticed it, since I'm comfortable with stalls and got on the brakes quickly -- "yeah it rocks, big deal". But another jumper, with less experience, was weirded out by what to him was a really scary opening.

[masterrigger1 2]

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which is also the only reserve that should ever be assembled into a Sigma,

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On what basis do you make that decision?

It is not his decision...http://www.unitedparachutetechnologies.com/index.php?option=com_content&task=view&id=108


Cheers,
MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[diablopilot 2]

That's not a FAR.

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You're not as good as you think you are. Seriously.

[tetra316 0]

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That's not a FAR.

So you advocate ignoring the manufacturer's recommendation? Just because you can doesn't mean you should or that's its okay.

[BKR 0]

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That's not a FAR.

This is enough clear in the AS8015/B


5. COMPONENT QUALIFICATIONS:
5.1 Parachutes may be qualified as complete assemblies or as separate components (such as a canopy, a
stowage container [pack], and/or a riser). The airworthiness of a parachute assembly, including other
separately approved nonoriginal components, is the responsibility of the manufacturer who performs the
certificating tests for the parachute assembly. The manufacturer shall publish and make available a list of
interchangeable components which have passed the following tests in 4.3 when tested in conjunction
with the assembly or component(s) being certificated.

Jérôme Bunker
Basik Air Concept
www.basik.fr
http://www.facebook.com/pages/Le-Luc-France/BASIK-AIR-CONCEPT/172133350468

[riggerrob 643]

You just described a normal opening on a PD 360 canopy.

I am so old that I used to jump PD 360s when they were fashionable as main canopies.
Bill Booth explained to me that the only way they could get PD 360s to survive terminal openings was to pull the brakes down into a deep stall, to delay cell inflation.
So all that bucking and rocking backwards and forwards is normal on a PD-360.
The only thing worse is when a lower brake line catches on the end of an L-Bar link!!!
Why UPT doesn't sew an extra steering guide ring at the top of the risers is a mystery to me??????

[diablopilot 2]

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That's not a FAR.

So you advocate ignoring the manufacturer's recommendation? Just because you can doesn't mean you should or that's its okay.

I'm saying that if the manufacturer is setting a "rule" in this case they are over stepping their bounds.

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You're not as good as you think you are. Seriously.

[bclark 0]

I like the way the PD360R flies once the brakes are unstowed. The rock and roll openings are a bit unsettling if you are not prepared for it. The steering line / L bar hangup is also a concern. I hate to think about how that reserve is going to land an unconscious tandem pair with the brakes stowed.

I would like to see the manufacturer put some thought into how to change these two design characteristics.

How to change the reserve to withstand a terminal reserve opening at max gross. weight and not open in a stall. (Providing a more survivable landing for an incapacitated load.)

How to change the steering lines / connector links to make controllability problems on brake release less likely or impossible.

These thoughts based strictly upon the concerns of a TI, not a rigger / designer / engineer or manufacturer.

[irishrigger 32]

i have quiet a few tandem reserve rides(20+),and no i am not chop happy either,just been very unlucky in some cases.and i havent packed any of those myself!
i also find that the vtr-360 does a rock and roll+stall opening in certain situations.normally when cuting away from an almost perfect canopy(broken steering line for example) and especially if you have a SKYHOOK! in the old days before the skyhook,you would have maybe 2sec seconds before the canopy would start to inflate,but with the skyhook that is down to almost .4 of a sec.so you havent had much time to build up some speed.and hence this horrible opening.
when i have been flung aroung the sky( line over or tension know)i dont seem to have the problem.
but when i teach the new guys i drill that in to them and it can be scary indeed.you need to be quick of your mark to get on the reserve riser or brakes depending on the situation.
but i am glad to say i always had a great and soft landing on the vector reserve.indeed to many landings actually.and hopefully something i will not have to do again!
i wonder also if riggers are rolling the nose of the tandem reserve???

my 2cents

rodger

[riggerrob 643]

" ...i wonder also if riggers are rolling the nose of the tandem reserve???

my 2cents

rodger

[Kimblair13 0]

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You just described a normal opening on a PD 360 canopy.

Like I said I've seen quite a few of these open. Yeah they rock and roll a bit before you pop the toggles.
But what I'm talking about is far far far from normal. I wish I had video of them opening cuz you definitely wouldn't think "normal" when you see it. It'd be more along the lines of "holy shit". And continues for quite awhile even after the toggles are popped.

And like I said it's just one place that I'm seeing them this bad...

SO, I guess my real question is...what kinds of things, if any, do you think would/could make the openings surge and stall so much.

[billbooth 10]

I have hundreds of jumps on 360's as a main, and the "rock and roll" opening can be avoided if you simply release the brakes as soon as the slider comes down. I suspect that the Vector 360 tandem reserve is the longest, continually produced ram air reserve there is (over 25 years now)...and it also has well over 10,000 tandem jumps as a main. So far, it has worked damn well. Although I have brough a lot of change to harness and container design, I basically still believe in the old adage, "If it ain't broke...don't fix it". Any new reserve I put out would be starting over from scratch, and it would take at least a decade before I know if it is anywhere as safe as the 360 has proven to be. I have enough "new" designs out there to worry about. I don't need another one, thank you.

[RIGGER 0]

You should know that from your Sigma / Vector Tandem course.

Just release the brakes & all is good.

Be Safe !!!

[feuergnom 29]

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I basically still believe in the old adage, "If it ain't broke...don't fix it". Any new reserve I put out would be starting over from scratch, and it would take at least a decade before I know if it is anywhere as safe as the 360 has proven to be. I have enough "new" designs out there to worry about. I don't need another one, thank you.

if this wasn't bill booth himself stating this but any other manufacturers rep he'd be shredded to pieces instantly

The universal aptitude for ineptitude makes any human accomplishment an incredible miracle

dudeist skydiver # 666