parachutes

General discussion about the sport of hang gliding
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Tad Eareckson
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Re: parachutes

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http://ozreport.com/forum/viewtopic.php?t=28605
Mart blows up his glider
Jeff Shapiro - 2012/07/20 23:28:14 UTC

Mart,

I was super happy to hear that you were able to do what was necessary to deal with your broken glider and get to the ground reasonably safe. Strong work getting your chute out and having the composure to achieve the best outcome for a scary end to your final glide. I hope your recovery is fast and you get back in the air as quickly as is possible. If I can help you in any way, drop me an email.

Cheers,
Jeff Shapiro
Aren't you gonna say anything about how super happy you are about the Screamer working so well?

Slimeball.
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Re: parachutes

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=28605
Mart blows up his glider
Mart Bosman - 2012/07/22 06:34:46 UTC

The glider was a three year old Airborne C4 in very good nick. Never a bad landing/broken upright. Never fallen from a car or anything like that.

Eyewitnesses said that the wings just folded without a tuck. It seems most likely that the right wing crossbar broke in mid flight. The side cables are still intact.

My GPS shows I was only flying 90 km/h groundspeed at the time.
What does your GPS show about your descent speed prior to and after deployment?
I was flying faster before but I had reduced speed because the air was a bit lively, by no means I would call it turbulent.

We left Gauche with a light cross tailwind and the wind on the landing field was a slight headwind.

I have no idea why the crossbar failed at such a low speed.
Was something like this:
While pushing up on the leading edge between the nose and the crossbar junction, step on the bottom side wire with about 50 lbs. of force. This is a rough field test of the structural security of the side wire loop, the control bar and the crossbar, and may reveal a major structural defect that could cause an in-flight structural failure or loss of control.
included in your preflight checks?
I was wearing a 4fight Icaro helmet. I bought that helmet when it became available at the Europeans in Millau in 2004. I hit the rocky ground very hard with the side of my head. Besides the vertical decent, I was still rotating very quickly under the glider.
I'm guessing you mean under the parachute.

And I'd say that parachute was too small to do the job.
They kept me in hospital for a night because I kept loosing consciousness for short periods of time in hospital when they were checking me out. I have no doubt whatsoever that I would have been a lot worse of if I hadn't been wearing a decent helmet.
And you'd have been a lot better if you'd have had a parachute that have let you down slowly enough to prevent the wreckage from spinning like a top.
The parachute is a Dutch brand Aeronautic Sails and rated for a max pilot weight of 123 kg.
So we can just ignore the weight of the glider.
I had a WW swivel installed when I bought the chute in 1998.
Good thing - you might have been dead otherwise. So how come the parachute didn't come with one? It's almost a no brainer that if you need a parachute what's left of the glider will be spinning.
My harness is a WW Covert. This harness comes with a Screamer to minimize opening shock and I remember being surprised by lack of it when the chute appeared above me.
- I guess it was a lot higher the previous time you threw your chute after a cross spar failure. How many Gs would you guess for with and without?

- You got a concussion upon impact but the opening shock was very comfortable. Super.
Even though the chute is large it looked very small.
It was very small. It was fully deployed and you were wearing a good helmet and you still hit so hard you were losing consciousness at the hospital.
Jerry Furnell - 2012/07/22 07:24:12 UTC

Thanks Mart, that was very helpful.
Have you spoken with Airborne?
It would be interesting to know where the Xbar broke.
Have you had the glider from new?

I'm not familiar with a Screamer... is that part of the chute or an add on?
It's a placebo.
Mart Bosman - 2012/07/22 07:41:11 UTC

Yes, I've had the glider from new. A very good glider, no problem keeping up with anybody but my own limitations.
My sprog settings were not changed from the worlds in Italy last year and were actually a little bit higher then the factory allowed me to have them.
The Screamer is on the harness. I hadn't seen it before on other harnesses. It is basically some double stitching that rips when a chute is deployed.
Jeff can elaborate on it, since he designed the harness.
Yeah Jeff. Let's hear about it.

Let's hear about how dramatically it reduces opening shock and see some pictures. Let's hear about the valuable information you got back from Yates after their testing. I'm still finding nothing about it on your website.
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Re: parachutes

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=28605
Mart blows up his glider
Lin O'Driscoll - 2012/07/22 17:06:49 UTC
Los Angeles

Some good info on Screamers, and pictures here...
http://www.yatesgear.com/climbing/screamer/index.htm
Yeah Lin, and you can some good info on the new and improved Lookout two point aerotow release and pictures here:
http://estore.hanglide.com/Aerotow_Primary_Release_p/14-9004.htm
But you can get much better info on the new and improved Lookout two point aerotow release at:
http://www.kitestrings.org/post41.html#p41
and
http://www.kitestrings.org/post503.html#p503
Likewise you can get much better info on the Screamer if you start reading at:
http://www.kitestrings.org/post1623.html#p1623
I believe they were initially designed for climbing to take some of the force out of a fall on delicate gear placements, but like the idea of using them with chutes.
So did I - until I got some good help understanding the physics of the issue.
Jeff Shapiro - 2012/07/22 22:11:50 UTC

Covert Screamer

The "screamer" is a load limiter sling designed to reduce impact force to a quickly loaded system thus, adding dynamic relief meant to reduce stress to both the user and the system. They have been used in the climbing industry for years and I have personally experienced the benefits from their use while on difficult mixed ground (for me ;-) while climbing over suspect gear.
Invalid.
It is important to note that because of some of the design limitations I've had to consider, relating to the already tight accommodation common for a standard chute in a competition type harness, include the inability to have the screamer involve a long enough "blow out" section to effectively reduce impact force at, or even close to, terminal.
That's not even close to a sentence.
The screamer in the Covert will not do that and was not designed to do so. In climbing, a long fall might be 36 feet. In that distance, a speed of 32 mph is reached. A huge fall might be considered 63 feet during which 42 mph would be achieved. You can see why the shorter and more compact screamer sold at climbing shops for that sport would be very effective.
No. I can't.
The speeds involved are just not that high and along with other dynamic components (rope, distance from the anchor, the climbers body, etc) most climbing type screamers are very effective.
Cite data.
For a screamer to be effective in a hang gliding system, even one with a longer "blow out" section than a traditional screamer designed for the climbing industry (as in a Covert), it's my opinion...
Not a good sign.
...that the chute would have to come out of a pilots harness while, A: still attached to the glider, greatly adding to the drag, thus causing a slower fall rate and B: added to the dynamics present as the chute achieves line stretch, taking more time than "instantaneous" to open, also helping to keep the impact felt by the chute opening to a minimum.
So what you're saying is that in order for the Screamer to mitigate the opening shock, the opening shock has to be very mild.

Reminds me a lot of the standup landing one breaks arms practicing in ideal conditions to use in emergency situations. Then when you're in an emergency landing situation you're dead if you don't come in on the wheels.
Although this feature is not meant to be a solution for terminal openings in the unfortunate event that a pilot becomes detached from the glider...
It's actually the FORTUNATE pilot who becomes detached from the glider. For example - if Adam Parer hadn't become detached from his glider he'd have been dead. And in REAL aviation it's traditional to get away from your aircraft in a situation requiring a parachute. In fact a lot of the military planes incorporate elaborate and expensive systems to REALLY detach the pilot from his aircraft.

And becoming detached from one's hang glider doesn't put one at terminal. Having a shit container configuration which jams the parachute is what puts one at terminal. Does your Covert harness have any issues in that department? I haven't heard you say that it doesn't.
...in a standard deployment, it was my hope that the screamer would help to reduce the trauma caused by opening shock...
Yeah, that was my HOPE too. Then Jason Rogers walked me through the math and I took it back out of my system.
...(as it seemed to in Mart's case).
Yeah, as it SEEMED. Same way when a tornado rips through the Bible Belt it SEEMS that the prayers of the survivors worked to have their lives spared.
During the design and development phase of the Covert, I spent far more time making sure the harness structure equalized the load properly, directly to the leg loops with the chest strap there, mostly, to hold the pilot in the system securely. This was meant to create less tendency for a chest strap to load the back plate and squeeze around the pilots chest causing potential for broken ribs or lung trauma.
Oh. It was MEANT to. Do you have any indication that it actually DOES? Seeing as how you haven't told us that it DOES, I'm guessing not.
It's my humble opinion that the harness structure and how it carries a load during a deployment event is far more important than having or not having a load limiter as part of the system.
Summary...

- You have a back plate which will distort under the G loading you can expect as a result of the kind of spinning you typically experience after a structural failure.

- The back plate distortion is likely to make parachute deployment difficult or impossible.

- The Screamer's totally useless - in low shocks when you don't need it and in high shocks when you do.

- If your chute opens at terminal you can count on the back plate taking out some ribs and collapsing a lung or two.

Summary of summary...

These racing harnesses are DANGEROUS. In an emergency situation you'd be in a lot better shape in an earlier generation pod, cocoon, or stirrup.
I'm so glad that the intended effect of the screamer helped to make your deployment less traumatic, Mart.
Yeah, right.

Wanna say anything about the concussion he got at the end of his gentle descent to safety?
I'm VERY happy that your recovering well and hope you get back in the air soon. Be safe out there. Look forward to the next time we get to fly together.

Cheers,
Jeff
What a load of crap.
Jeff Shapiro - 2012/07/22 22:20:09 UTC

PS

I should also note that along with sending the screamer I sew (for the Covert) to Yates for testing, feeling that I wanted some personal experience, I jumped off of a platform for a static, factor 2 fall connected to one and what should have broke me in half was quite manageable ;-) Just sayin.
English or metric should have broken you in half and quite manageable?
Again, be safe out there!!
Zack C - 2010/12/13 04:58:15 UTC

I had a very different mindset too back then and trusted the people that made my equipment. Since then I've realized (largely due to this discussion) that while I can certainly consider the advice of others, I can't trust anyone in this sport but myself (and maybe the people at Wills Wing).
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Re: parachutes

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=26702
High Speed
Jack Barth - 2012/07/23 15:02:44 UTC
Southern California

Read on the Oz that a pilot had blown his wing up doing 70 mph. Can you imagine doing 70 and the VG releases? I can because I had mine slip out of my hand while pulled in on a Talon and it got seriously out of control quickly. Had the bar pulled in during strong landing conditions and went to adjust the VG and it slipped out of hand. Wing did a strong turn towards the hill. My only recovery was to increase the turn until I came around heading back into the LZ. Not a good feeling.
He wasn't doing seventy. He was doing 90 kilometers per hour groundspeed with a light headwind. That translates to 56 miles per hour, maybe a bit over sixty airspeed, VNE for the C4 is 53, BFD. I'm guessing Airborne won't be criticizing people flying their gliders in competition for that level of reckless behavior any time soon.
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Re: parachutes

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=28605
Mart blows up his glider
Mart Bosman - 2012/07/23 08:18:43 UTC

Attached you can see a photo with the screamed screamer.

http://ozreport.com/forum/files/dsc02068_185.jpg
Image
So IF you're gonna waste your time with this useless junk why not just throw a stock Screamer in between the swivel and the bridle?
I'll send the harness back to Jeff to see if he can repair it...
Which you wouldn't have had to do if you had just thrown a stock Screamer in between the swivel and the bridle.
.../learn from it.
Did you read his post? There's nothing to learn from it. He just told you it doesn't do anything. The climbers debunked this thing:

http://www.supertopo.com/climbing/thread.php?topic_id=323573
yates screamers
rgold - 2007/11/12 18:49
Poughkeepsie

The Yates site is is not entirely clear about Screamer functionality. Don't expect them to help that much for long falls. Their effect is primarily useful for short falls on crappy gear.
Jason Rogers debunked it for us in hang gliding, and Jeff just admitted that it doesn't do shit.

All you can learn from looking at the ripped stitching is that a pilot plummeting with a broken glider exceeded the activation load which, for the stock Zipper Screamer, is 450 pounds. Two big guys could blow that thing by tying it to a tree and hanging from it. Big fucking surprise.
It has done a very good job.
A four leafed clover in your wallet would have done a job so close to what the Screamer did that you'd never be able to tell the difference.
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Re: parachutes

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=30084
Parachute Bridle Attachment
Michael Grisham - 2012/11/26 15:09:06 UTC

What are the pros and cons of attaching the Parachute Bridle directly to the harness verses the traditional carabineer (Hang Loop)?
Are there safety concerns and performance differences between the two attachment points?
Opinions?
What better place to get OPINIONS about parachutes and carabinEErs than The Davis Show.
Jim Gaar - 2012/11/26 15:55:04 UTC

Quick Links will work.
Yeah. In case your carabiner fails. Think of all the lives that have been needlessly lost because people's carabiners failed and they had nothing left to keep them connected to their parachutes.
I think it's always a good idea to be attached to the parachute, just in case there is a separation.
Name a configuration - other than Bo's and those of the morons who turn their carabiners around backwards to prevent them from getting blown apart from the inside by the portion of the tow force permitted by their standard aerotow weak links - in which the pilot can become separated from the parachute.
It's not that difficult to set up...
Idiot.
Kinsley Sykes - 2012/11/26 21:49:13 UTC

Some comp harnesses attach the parachute directly to the harness backplate up near the shoulders versus the more typical attachment to the carabiner. Brad Koji died in a an accident where just such an attachment point was used. His neck was broken by the parachute bridal.
BridLE.
As far as I know, no one was able to conclusively state if the attachment point was the root cause of his death or just a coincidence.
Bill Bryden - 1999/05

Brad Koji, one of our premier competition pilots, experienced a tumble in his glider, presumably due to turbulent conditions during a New Mexico competition. He deployed his parachute but the bridle, which he had attached to his harness shoulder straps to ensure a feet-first landing, entangled around his neck, breaking it upon the chute's opening.
It was the cause of his death. His neck wasn't broken as a consequence of opening shock. (If Adam's neck wasn't broken as a consequence of opening shock nobody's could be, we've got plenty of data from skydiving reserves, and Brad wasn't separated from his glider.) Also... If the medical examiner wasn't able to determine from trauma to the skin that the bridle was the culprit the guy was a total idiot.
Have there been any deployments with the direct attachment method since Brad's accident - at least ones where the glider stayed intact?

Blindrodie,

You are right that it is pretty easy to add a Mallion Rapide...
Try "MAILLON rapide".

Better yet - try QUICK LINK. You're having WAY too much trouble in English to be dabbling in another language.
...between the parachute bridal loop and the harness main as a redundant back up (is redundant back-up an oxymoron?)
Yes. And, in this case, totally unnecessary and stupid.
Jim Gaar - 2012/11/26 22:07:29 UTC

Adam Parar (sic)...
- ParEr

- "(sic)" does not mean "I'm too stupid to know how to spell his name and too lazy to look it up."
...survived a detachment from his wing and lived to tell about it.
- As opposed to surviving a detachment from his wing and NOT living to tell about it.

- He survived BECAUSE he was detached from his wing.
Tore him up pretty bad when the chute opened.
- He got torn up because of a dangerous harness design which prevented him from deploying his chute until after he was going half the speed of sound.

- Nobody's ever addressed that issue.
Brought about a good discussion on the use of "Screamers" that reduce shock loading when the chute opens.
They DON'T. And if you'd had enough in the way of brains to listen to Jason Rogers and me after Adam's incident you'd know that.

If you wanna reduce opening shock:
- get the parachute out before you've plummeted four thousand feet standing upright in your racing pod
- get a bigger parachute
- don't use a PDA
If I was to deploy I would want the initial shock to be taken by the control frame for sure.
The CONTROL FRAME? The control frame consists of two downtubes and a basetube and it won't be taking any shock for you.
I can't imagine a chute that was only connected to the harness, Screamer or not!
We'll just add that to the list of things you can't imagine then.
Seems it would be tough to set up a chute that was attached to both the wing and harness and how one would set it up to load the control frame first...
Why don't you make that you're special little project and get back to us when you have something.
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Re: parachutes

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Re: parachutes

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=33404
Rapid parachute deployment
Dave Jacob - 2015/09/11 16:21:50 UTC

I didn't want to distract the thread on the recent fatality in Spain with a technical discussion but I started to question our parachute system given what we know of the circumstances from that incident. So forgive me for starting a new thread if you think I should have kept things more tidy.

I want to have a parachute that will open quickly in case I'm close to terrain when I deploy.
Fine. Use a smallish PDA with a short bridle and a ballistic deployment system.
I also want it to open readily if I'm in a descent that is slowed by hang glider wreckage. But I don't want to overly shock the system and risk catastrophic failure if I'm moving too quickly.
Pick one.
Selbaer...
...(Marco Weber) is a fuckin' asshole.
...included a very good write up from...
...the late great...
...Adam Parer that also illustrates the risks of a rapid deployment at speed.
What that illustrated - idiot - was the risk of using a shit engineered racing harness with a placebo parachute system.
http://adam-parer.blogspot.com/2009_11_01_archive.html

In the rock climbing world, we are sensitive to shock loads.
Not so much...

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Jim Rooney - 2011/08/28 19:39:17 UTC

One of the biggest bits that seems to be under appreciated is the bit that weaklinks break under shock loading.
...in hang gliding.
They can cause the protective pieces we use to anchor our ropes to the rock to pull out in the event of a fall.
In hang glider aerotowing that sorta phenomenon is considered to be a good thing.
They can also result in gear failure or injury to the climber. The video linked below shows some testing of dyneema and nylon slings. One thing they focus on is how much knots can weaken the system. (Yes, knots weaken the system and should be avoided for shortening hang straps.)
Yeah, you could reduce your suspension capacity from fifty to just twenty-five Gs. You'd thus be twice as likely to plummet to your death. (Make sure you remember to knot your backup loop in a similar manner to keep everything proportional.)
But the other take-away is how the dyneema (despite being equally strong or stronger) will fail because it lacks the ability to stretch forcing all the energy of the fall to be caught in a shorter period therefore making the load it experiences much higher.

http://vimeo.com/27293337


Yates makes a series of products called Screamers. Unfortunate name.
Fake concept.
But the idea is to stretch out the energy of a fall by blowing out sacrificial stitches that hold a length of webbing into an folded configuration.
Yeah. That's the IDEA.
No longer interested.
I don't know if a currently offered Screamer optimally matches our shock damping requirements.
- Bullshit.
- What, exactly, are "OUR" shock loading requirements?
I think that would take some interfacing with our reserve manufacturers.
If you've come up with this idea and it's valid and our reserve manufacturers haven't then what's that say about our reserve manufacturers?
I don't think it would take too much work to develop proper fit though.
What's a "proper fit"?
And I could see installing one of these in series with our reserve umbilical.
What the fuck is a "reserve umbilical"? Parachute "bridle" kinda sucks 'cause it's not a bridle but why use an even stupider term for it?
That would lessen the shock of the opening without compromising the time it takes to open.
Bullshit. It's all trade-off.
Has anyone out there tried something like this or know of any reason not to do it?
Yeah. I "tried" it the better part of a decade ago. I was the first and probably only person on the planet to try it. I wrote about it and - as usual - got totally ignored. Then after it got explained to me by better physics people how it didn't actually DO anything I untried it.
Red Howard - 2015/09/11 16:40:34 UTC

Dave,

I could see using a Screamer in parallel with our umbilical systems...
Oh good. A new stupid term has successfully entered the hang gliding lexicon.
...but maybe not in series. Then, whether the Screamer works as advertised or not, you have a complete, unmodified umbilical system doing exactly what it is intended to do. If the Screamer works...
Which it DOESN'T.
...it reduces the "opening shock" load as it should.
Why is "opening shock" in quotation marks?
If the Screamer fails in some way...
Fails it WHAT way, asshole? It either holds or it blows apart. And you're fuckin' parachute is gonna blow apart at a fraction of what the Screamer will.
...well, the umbilical system is still going to work normally.
If the "umbilical system" doesn't get wrapped up by the glider wreckage and if you don't hit the ground first.
With the Screamer in parallel to the umbilical, you could not use a very long Screamer (when stretched), unless the umbilical system is lengthened properly, to match.
Get fucked, Red.
Dave Pendzick - 2015/09/11 16:46:18 UTC

A parachute should open fast. Staggering a deployment to prevent injury or "catostrophic failure" is a moot point if you pound in before your parachute is able to open.
So try to have your major catastrophes at altitudes at which you can be arrested with the equipment of your choice with at least twenty or thirty feet to spare.
The more complexity you add to a system offers more chances for things to go wrong.
Which is why FA-18 Hornets are so much more dangerous to operate in turbulence at low altitudes than paragliders. (Asshole.)
A parachute system should be very simple to allow as few Murphy's as possible to enter the equation.
Yeah, take the swivel out if you have one. Also consider dispensing with the deployment bag.
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Re: parachutes

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=33404
Rapid parachute deployment
Dave Jacob - 2015/09/11 17:01:05 UTC

Dave,
Fuck Dave.
The deployment time of the chute would not be effected...
Affected.
...as the activation load for the screamer can be set above the loaded needed to deploy.
No. It can't. The activation load is preset at what it takes to blow the first row of stitching. And there's no fuckin' way any chute can NOT fully deploy before ANY Screamer starts kicking in. (Two kiloNewtons for all of them.)
What it does is reduce any shock load above a certain point once the chute is open.
Not enough to justify installing it in the system.
If the deployment is gentle, the screamer won't activate.
450 pounds. Good luck.
I agree we are adding complexity which is not preferred.
No you don't. You're preferring to add complexity because you believe it would REDUCE likelihood of failure. And if the Screamer actually worked as claimed you'd be right.

Fuckin' parachute system itself is a HUGE increase in the complexity of the glider assembly. And I'd guess about half the deployments are inadvertent result in a lot of carnage. But I'm not hearing any of these KISS assholes advocating its removal or suggesting that inadvertent deployments are inevitable.
I think it's a personal decision...
Fuck personal decisions. If this sport had its shit together and Screamers actually did what they're supposed to they'd be in the same universal use that deployment bags and swivels are.
...but I would be willing to accept some additional complexity if it mitigates the risk of an event I'm not otherwise prepared for.
Just not when considering release systems that actually work with respect to the simple Industry standard ones.
Some will not and that's fine. I for one was glad to have a swivel installed on my parachute when I deployed as it provided a stable descent so I could maneuver my body to a safe position for impact.
- See? (And I hadn't read ahead on this one.)

- That's not what a swivel does. A swivel prevents spinning glider wreckage from twisting the shrouds and strangling the canopy. People used to die as a consequence of that phenomenon. (Fuckin' incredible that that's what it took to get The Industry thinking about swivels.)
Dave Jacob - 2015/09/11 17:16:23 UTC

That's a good point Red.
All of Red's points have been good since T** at K*** S****** was banned and unable to post that he's full o' shit and explain why.
I think we'd need a special umbilical anyway to do it your way as you are probably going to bar stitch an attachment loop into it.
I showed you how to do it already:

http://www.flickr.com/photos/aerotowrelease/8321440784/
Image

But I failed to refer to it as a special umbilical so I guess it's not legitimate.
So perhaps the extra length isn't an issue. I certainly like that your approach keeps the Screamer from adding a new failure point.
Me too. Red's really excellent at proposing solutions to nonexistent problems.
Brian Scharp - 2015/09/11 17:34:20 UTC

http://www.hanggliding.org/viewtopic.php?t=14607
Parachutes and free fall.
http://www.hanggliding.org/viewtopic.php?t=14592
Opening Shock
http://www.kitestrings.org/topic45.html
parachutes
Cool Breeze - 2015/09/11 18:20:00 UTC

The screamer is just tubular webbing sewn together in "rolling loops" the stitching needs to rip apart, and that's what absorbs the load.
In "theory".
So in theory...
See above.
...the screamer could be made of webbing that is stronger than the rest of the bridal- meaning that you would not have to use in tandem/parallel to the bridal.
- See? It's a bridal - not an umbilical.

- The weak link is the fucking parachute - not any of the fucking webbing. (But trying to explain the concept of a weak link to hang glider people...)

- After the Screamer's blown it's a loop of one inch tubular webbing - 5845 pounds. For a 250 pound payload that's over 23 Gs. What's the chute good for?
If the shock load is not severe enough... screamer does not activate. If the shock load is severe... it activates.
Severe. A little less than what I'd be pulling in a sixty degree banked coordinated turn.
One could design a screamer that could be x amount of feet long to get the job done...
Or one could just use a bigger chute that opened slower.
Red Howard - 2015/09/11 18:54:50 UTC

Cool Breeze,

CAUTION: Tubular webbing should not be used in a parachute bridle, due the the way it is made.
Tubularly.
This is an extremely serious design flaw, in older gear.
But the standard aerotow weak link wasn't. At least not one not worth worrying about. At least not until after one whipstalled Zack Marzec into a tumble at 150 feet.
Consult a parachute rigger or manufacturer for the right stuff.
Nah, do it right and consult Jeff Shapiro.
If an inspection reveals any tubular webbing in any HG reserve bridle, immediately have that webbing replaced with the correct modern webbing.
Or use your fucking brain and install it between the swivel and the parachute where it's not an issue.
Older parachutes may still be found with tubular bridles, so let the buyer beware.
And don't worry that everybody and his fucking dog is now using a Tad-O-Link in conjunction with a Bobby Fucking-Genius Bailey bent pin barrel release.
It may be possible to make a Screamer strong enough to meet our...
...idiot imaginary...
...needs, but until somebody...
...other than T** at K*** S******...
...steps up to say so publicly, I would not assume that any available units will do the job, for now.
Course not. That would require looking at specs and doing grade school level arithmetic. Why do that when we can just wait for somebody - preferably Jim Keen-Intellect Rooney or Ryan Instant-Hands-Free-Release Voight - to step up and say something publicly?
Cool Breeze - 2015/09/11 20:35:47 UTC

Scratch the word "Tubular", just think webbing. You old birds don't take kindly to fresh ideas.
Or intelligent decades old ones.
A screamer type device is the solution to our problem. Simple idea that works.
Like the Rooney Link with its huge track record. 'Cept without any track record.
2015/09/12 00:04:35 UTC - Sink This! -- NMERider
Brian Scharp - 2015/09/11 22:35:19 UTC

Fresh? A 2009 debunking is provided in the links above.
Huh? What? Thought I heard something. Must've just been the wind. Now where was I?
Dave Jacob - 2015/09/11 23:57:45 UTC

Hey Brian,

Are you referring to Jason's analysis from 12/29?
The one that shows that the Screamer doesn't actually do anything? Yeah, that one. But just ignore it 'cause we've just established that it's a simple idea that works.
Brian Scharp - 2015/09/12 00:53:05 UTC

Yes, and this one posted:
2009/11/28 19:52:17 UTC
Red Howard - 2015/09/12 01:59:22 UTC

Cool Breeze,

YOU dredge up a nightmare from our HG past, tubular webbing.
Bull fucking shit. Tubular webbing is ONLY problematic when it's under tension and within range of the flying wires.
I give a serious Caution on that stuff, and so I get "You old birds don't take kindly to fresh ideas"? REALLY? Then you dismiss that deadly concern, rather too casually.
You give serious Cautions at every opportunity to never do preflight stomp tests on the sidewires and then when a motherfucker gets killed right after launch 'cause he didn't do a preflight stomp test (ever) you're nowhere to be found.
If you re-read my posts here, I gave the Screamer concept some careful consideration, and suggested a way that it could help (if it works), and nothing goes bad if it does not. I see that scenario as the best of all possibilities.
Yeah? How 'bout rigging one up and taking some pictures so the rest of us can get things right - the way the sport did with the aerotow release Paul Hurless designed.
For the record, I DO take "kindly" to any new ideas that might improve the safety of my flying community.
I shudder to think where the sport would be without all of your endorsements of new ideas that might improve the safety of YOUR flying community.
Fair and frank discussion (including possible flaws or benefits of an idea) is what we do here.
"WE" certainly do. That's Jack's Living Room has always been such a cauldron of evolutionary progress for the sport. And you've still got time left over to jerk each other off at satisfactory intervals.
Not every idea meets instant approval...
Well, a standard aerotow weak link with a huge track record only comes along about once in a generation.
...but with a little tweaking of the operation, these things may become life-savers.
And ain't it great that we have an institution like The Jack Show to continually drive the sport forward - succeeding where all the equipment manufacturers have failed so miserably.
It can be your mission to present new ideas, and that is fine, but it is not your job to shoot down any "opposition" that you may perceive (wrongly, in this case).
'Course not. It's YOUR job to shoot down any "opposition" to any established Jack Show theology.
Dave Jacob - 2015/09/12 02:24:42 UTC

Hey Brian,

First of, thanks for digging up the threads. But I think 'debunked' is too absolute of a term for this case.
No it's not. It's totally on the money.
I realize its the best we can do in the absence of real data but correlating steady state loads to dynamic events can leave huge uncertainties. Further, every hand calc I saw in your links assesses existing products designed for rock climbers which rely on a dynamic rope (stretchy) and a much shorter fall than we'd experience.
So multiply your Screamer by ten. Then multiply that result by zero.
The concept of using load limiter is a correct approach for minimizing shock loading.
The concept of using a bigger chute and a longer bridle is the correct approach for minimizing shock loading. But then you have to figure out how to get yourself into an Adam Parer situation to justify the extra weight you'll hafta carry around on all the flights you don't get yourself into an Adam Parer situation and hope you don't get yourself into a low altitude situation in which you need to stop on a dime.
I spent six weeks recently analyzing a split rotor failure in a high speed turbine. The resulting torque spike was dropped by a factor of three with a crush zone that collapsed in three miliseconds. It got us down to something we could manage. I believe you are technical so you know system rigidity is the dominant driver in setting the shock load magnitude which in-turn is what causes the damage. The question is not so much whether a load limiter will work. The question is what are the loads and what is the proper design for the load limiter.
Here's another question... Where are the incidents that indicate that this load limiting bullshit is worth spending any time and energy on?
The problem as I'm beginning to understand it (thanks to the help of an unspecified manufacturer) is the relative obscurity of this type of failure (and we are still not sure what happened in Spain)...
One thing we're totally sure about with respect to what happened in Spain... Didn't have shit to do with any shock loading issues. Another thing we're totally sure about... Whatever it was a halfway decent preflight inspection would've handled the problem(s).
...does not justify pulling engineering resources off other programs which have a more significant impact on pilot safety.
Goddam fuckin' right. Preflight stomp tests, hook-in checks, belly landings, releases that don't stink on ice. And think how much better off Craig Pirazzi would've been if just one of the individuals involved in this useless discussion had donated a minute's worth of wire assistance to the launch.
In short, a pilot can add a Screamer or similar device. Assuming they do it properly, they will lower the maximum load provided the deployment generates enough force to activate the device.
And if the deployment DOESN'T generate the approximate two Gs needed to activate the device ya don't really need the device, do ya? ("Damn! Wish I'd been going eighty miles per hour faster so my device would've worked." ""Damn! Fuckin' airbag didn't inflate! Next time I'm heading for a tree I'm gonna stomp on the gas instead of the brake.")
But there is no guarantee it will sufficiently damp the system to avert a failure.
There are no guarantees of ANYTHING good happening after you've done a lot of stupid stuff in aviation.
Until a solution...
...to this nonexistent problem...
...is properly engineered, I think the best policy is to make sure you can get your chute out fast even if that means you have go with a less aerodynamic harness.
Oh! You mean we maybe SHOULDN'T use a harness with a frame that bends and chokes off the deployment port in a tumble? That we should maybe give some thought to properly engineered harnesses before going nuts about properly engineering Screamers? So maybe it would be better to get a chute out at forty miles per hour without a properly engineered Screamer than at two hundred miles per hour with a properly engineered Screamer?

Wow! The Jack Show really DOES have all the really great new ideas that might improve the safety of Red's flying community!
2015/09/12 02:32:39 UTC - 3 thumbs up - Red Howard
Yeah Red. Totally agree. Your flying community is the BEST!
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: parachutes

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=33404
Rapid parachute deployment
NMERider - 2015/09/12 04:47:26 UTC

I'm going to chime in with my two cents.

There is nothing wrong with the current reserve deployment systems.
There sure was with Adam's. That crap damn near killed him.
The thing that is wrong is twofold:
1 - Too few pilots do enough practice tosses on a regular basis.
2 - Too many pilots freeze when it's time to toss their reserves.
Yeah, I've heard EXACTLY THE SAME THING about pilots who need to make the easy reaches to their Industry Standard releases. Maybe we could secure our parachutes with some fishing line which would break before our gliders get out of control. It could increase the safety of the flying operation at the cost of a bit of inconvenience every now and then.
I removed the Screamer from my Covert harness because it's made from a type of webbing that flying wires can cut through too easily.
Oh. So what you're saying is that rather than fix the problem of the dangerous harness design Jeff used a fake solution to fix the fake fix for the dangerous harness design and made the harness even more dangerous.
I would never run a Screamer in parallel with my normal reserve bridle for the following reasons: If the Screamer does not fully rip open then the reserve shrouds are more likely to tangle with the wreckage of my glider.
Fuck you, Jonathan. red had the best idea for a parachute Screamer umbilical the world has ever seen and you're just pissing all over it.
There is a reason that hang glider reserve bridles are the length they are. Running a parallel system that could significantly shorten that bridle puts the pilot at needless risk. Furthermore by having a partially limp reserve main bridle it too can get tangled up in the glider wreckage and result in a fouled up reserve.
So? We've already got hang checks, upright flying, spot no-steppers, Infallible Weak Links, easily reachable bent pin releases, pro toad bridles, tug pilots who can fix whatever's going on back there by giving us the rope, backup loops... Why not have everything as consistent as possible?
I would never attach my reserve bridle to my internal harness webbing directly so there is nylon to nylon contact. During deployment there is a chance for friction build-up that will melt the webbing and I will free-fall with no reserve.
How 'bout running a secondary bridle through the lower eye of a primary bridle minus a thimble?
I always use a Mallion Rapide link...
Translation: Quick Link link. (It's "maillon", by the way.)
...of 7 or 8mm.

The Screamer was attached to the internal webbing of my Covert harness in this manner so that there may have been nylon to nylon friction build up and so I removed it for that reason too.
So why do you think idiot fucking Jeff Shapiro didn't just put a stock Zipper Screamer between the swivel and the parachute? Wouldn't be able to use this snake oil feature to help sell his harness as it wouldn't be a unique integral feature?
I have video of two friends of mine going to their deaths and both friends had ample opportunity to throw their reserves but failed to do so.
I have a track log of a Master rated tandem instructor and his eleven year old skydiving student plummeting to their deaths when the former had a window of all fuckin' afternoon to throw his reserve. But he was a u$hPa FOCUSED PILOT focusing on prying his shitrigged "release" open all the way into the lakebed.

http://farm9.staticflickr.com/8819/18267685796_64156e9c91_o.png
Image
Every time I fly I grab that reserve handle and mentally go through the deployment process. This way I can hopefully get the deployment bag in my hand without any hesitation. I don't even have to throw it in the event that the glider rights itself. I can land with it in my hand as long as the bridle doesn't snag on anything.
Well yeah, if ya like landing in those Happy Acres putting greens with all the girls and faggots. Not MY idea of flying though.
YMMV.
Damn right it does.
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