Kite Strings

Edit - 2015/11/06 21:30:00 UTC

Ignore this advisory.

There is NOT a problem with this release. There was a maintenance issue with an early version of this release that cropped up, as far as we know, ONCE, and was easily detectable and easily detected on preflight. Read on through these first three posts if you're interested in the details.
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P.S. - 2015/12/05 00:45:00 UTC

There's another release advisory down at:
http://www.kitestrings.org/post8658.html#p8658
and, if this topic reappears as a sticky, beyond.
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Joe Street's two point aerotow release:

http://www.getoffrelease.com/


which is adaptable for many other applications, has an issue which, if it manifests itself, WILL leave the upper bridle end tied to the keel. Apparently the whipping securing the cable housing to the quick link may be inadequate for securing the cable housing to the quick link. And if that happens the cable housing will shift forward and:

http://c1.staticflickr.com/5/4433/35531445133_87c70f9bdf_o.png


And of course (thanks again, God and Murphy) this is most likely to happen late in a lockout approaching weak link tension.

Recommendations...

http://www.flickr.com/photos/aerotowrelease/8318603266/


http://www.flickr.com/photos/aerotowrelease/8306300488/

Publicly blast your criminally negligent hang glider manufacturers and authorized dealers for selling their gliders to aerotowers with no options for towing them safely and legally and advising customers to always use an appropriate weak link with a finished length of 1.5 inches or less - after studiously ignoring for decades solid technology that's been developed by the muppet caste and handed to the motherfuckers for free. Tell them that because of their obscene negligence, hypocrisy, sleaziness in this and similar issues the US glider market is currently standing a significant likelihood of becoming extinct.

DO NOT be in a big rush to swap out Joe's release which MAY fail in an emergency situation for some Industry Standard piece o' total shit from Quallaby or Lockout which WILL fail in an emergency situation. We've very likely got one life saved in a TANDEM (pilot died, passenger lived) worst case scenario (heavy glider, lockout, higher tension) that very likely would've been lost had some Industry Standard piece o' total shit...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3107
I have a tandem rating!!!

Lauren Tjaden - 2008/03/23 22:20:15 UTC

When Jim got me locked out to the right, I couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the F'ing release slid around when I tried to hit it. The barrel release wouldn't work because we had too much pressure on it.

Anyhow, the tandem can indeed perform big wingovers, as I demonstrated when I finally got separated from the tug.

...from Quallaby or Lockout been used.

It may be, and I suspect this is the case, that the cable housing gradually works its way forward over repeated actuation cycles, rather than shifting catastrophically in the course of one hard pull. If this is the case it should be possible to monitor the play and manually work the housing back as required.

Dave Gills has advised addressing the issue PROPERLY:

Weld a cable stop to the quick link.

but this is something the average user will need to have done rather than be able to do.

Other than that, the only safe off the shelf solution for two point aerotowing I can recommend is the adaptation of the Kaluzhin release:
http://mouthrelease.com/
Dave came up with:
https://youtu.be/SpYdb-aIn6I
Draggy but bulletproof.

Also consider one point towing. Several easy, cheap, bulletproof bite controlled solutions - and totally clean 'cause everything's stowable. Substantial safety compromise but you pretty much need a Zack Marzec perfect storm:
- low
- freak monster thermal lift
- easily reachable release
- an appropriate weak link with a finished length of 1.5 inches or less (or tug driver fixing whatever's going on back there by giving you the rope)
to kill you.

What a state of affairs after Quest perfecting aerotowing for a quarter century and over three decades of practical hang glider aerotowing.

Discussion of this issue:
http://www.kitestrings.org/topic87.html
Kaluzhin Release as Primary w/ 2 Pt. Bridle Setup

Please discuss advisory issues on other/dedicated threads. If we start accumulating lotsa discussion posts we reduce the effectiveness of this topic's purpose.

<BS> - 2015/11/06 20:15:43 UTC

What causes the cable housing to move forward to compress the spring and what holds it in place?

Good question. I've had some correspondence with Joe and we can't figure out a good answer. Joe does a quality job with the whipping and I'm not seeing how this mechanism could be in proper condition and looking OK at the beginning of the day when the glider's preflighted and then lock as illustrated and described in the course of a couple dozen cycles through the day.

I think this was a problem with the operator - who's demonstrated some major competence issues by not reporting on this and:

Joe Gregor - 2006/05

2005/07

An extremely experienced pilot was launching a new Falcon 2 via scooter tow. The bridle system used employed two lines: one attached high on the harness for the initial climb-out, and one attached lower for the high altitude portion of the tow. The pilot failed to hook in prior to launch and held onto the control frame (assisted by the upper towline hanging over the bar) until he released at approximately fifty feet. The glider was locked out by this time as the pilot let go with one hand to effect the release. The pilot was propelled through a pine tree, dislocating his shoulder and breaking an arm. The reporter listed a number of factors contributing to this accident including: moving the glider while wearing the harness unhooked; failure of pilot to perform a hook-in check, perhaps due to shared responsibility for the launch; fatigue at the end of a long day; use of a double release system that is difficult to locate in an emergency; poor radio communication with the tow operator; and possible lack of a weak link. An additional factor may have been the high experience level of the accident pilot leading all involved to worry less about backup safety checks.

Until/Unless we get some better information on this and some corroborative test results or info from the field my recommendation now is to do reasonable preflight inspections at reasonable intervals and otherwise not worry about this single second hand account of an issue.

And bear in mind that the mainstream crap fails at such astonishing frequencies that none of the commercial operations patrons think release failures are anything but harmless and inevitable glitches that pop up a dozen or so times a good weekend and totally unworthy of mention - or consideration as relevant issues whenever a Mike Haas, Roy Messing, Steve Elliot buys a farm.

This just in from Joe:

Joe Street - 2015/11/06 21:07:15 UTC

Why did I find out through this channel? Wouldn't it be logical to report any issue directly to the manufacturer?

I sold that release on the 3rd of May of 2012 and I didn't start whipping them till early the following year. Likely that release looked like this photo.

http://c1.staticflickr.com/1/592/22415258538_4823877b8d_o.jpg


I don't think the whipped and glued cable would move unless it became severely abraded and actually started to come unwound. I pulled so hard on these that the PVC on the outside of the housing stretched and the inner metal deformed but the whipping didn't budge.

Gotta consider our sources. Total fucking nonissue as far as I'm concerned. If we need an advisory mine would be to stay the hell away from John - as well as the rest of the Industry Standard Industry.

Joe Street - 2015/11/07 02:03:27 UTC

Mystery solved.

John received a release which was an early version but after the problem with the cable ties was discovered. I used industrial grade heat shrink with internal adhesive and I tested the idea to failure, which, again, was on the cable housing, not adhesive failure. See photo of the attachment method.

http://c2.staticflickr.com/6/5666/22829034512_5c4e38f058_o.jpg


It was so much better than the cable ties I couldn't see it ever being a problem, but I guess over time the adhesive failed. John fixed this with hose clamps (see next photo):



and continued to use the release for a while and said it worked well but he eventually decided to switch to a LMFP release because he liked the bicycle handle.

You mean the LMFP release with the brake lever LMFP gets from Wallaby that they use on their own gliders versus the LMFP without the brake lever that isn't warranted as suitable for towing anything that they sell to us muppets.

Anyways I had a devil of a time getting the thick walled heat shrink on the quick link (to the point of damaging my hands) so I decided to go for the whipping and gluing, despite it being more time consuming and laborious (I remember discussing it with you at the time)...

Yeah:

Joe Street - 2013/04/14 20:52:49 UTC

I made some changes to the releases. I tried to find a production friendly way of securing the cable at the release end but eventually had to resort to the time proven method of whipping. I did the same at the lanyard end. It adds a bunch of labour and time to each unit but what the heck, it's the best solution I think.

...and John was the only one who got a heat shrink one as well as I can determine.

So it seems that John didn't deserve to be blasted for having a catastrophic failure and not reporting it. Sorry John.

What the hell. Well intentioned. Good drill for us. No harm done. Now we have a better understanding of the engineering and mechanics of this mechanism.

And John should've put out an immediate advisory on the issue.

I'll be continuing this discussion and addressing more of this post starting at:
http://www.kitestrings.org/post8653.html#p8653

The purpose of this thread is to advise about issues for which Kite Strings related people bear some responsibility. For issues for which enemy forces are responsible there's the rest of the forum.

The first item addressed here turned out to be a pretty much total false alarm. For the first REAL issue...

http://www.flickr.com/photos/aerotowrelease/8305333309/


This one's pretty painful 'cause it's largely my baby - although an adaptation of a concept of Steve Kinsley's - and I really loved it.

The four-string has too much force step-down to blow at normal tow tension and thus can't be relied on to blow in a lockout when towing one point or when used as a secondary in a two point system after a bridle wrap (although a bridle wrap is likely to blow a proper secondary weak link).

Needs to be a three-string.

Incident report and discussion at:

http://www.kitestrings.org/topic61.html
4strings release

Pretty confident this'll be the last issue that needs to be publicized here.
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2015/12/05 00:00:00 UTC

I (Tad) will shortly be unsticking this topic and letting it fade back in the normal lineup of topics.
- The first issue turned out to be - for all intents and purposes - a total false alarm.
- The second issue wasn't a real biggie and there's probably only one copy in circulation and that's the one in which the issue was discovered.
- I don't feel that issue merits peperpetual top billing in the main active section of the forum.
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2015/12/09 14:46:09 UTC

Unstuck - precisely one month after the appearance of this post.

Don't pull your inventory, ferchrisake. Just wait until one of these kills somebody...

http://ozreport.com/pub/images/robinsshacklebig.jpg



Then...

http://ozreport.com/9.009
2005 Worlds

Davis Straub - 2005/01/11

This type of release mechanism...

...has been banned (at least for a short while) from the Worlds at Hay.

...have it banned for three or four days at the relevant venue. Problem solved.

Crap. A bit bummed out by this development. My previous only issue with this hardware has been that it's overbuilt - a lot more robust/heavier than it needs to be. And it was never refined. It wasn't broke so nobody ever fixed it. And now...

Compare/Contrast:

http://www.flickr.com/photos/aerotowrelease/8306258400/


No one would be able to make Tad's Rube Goldberg job fail with a million dollar prize and a gun to his head. Gimme a pin with a bit more length and thickness and I can give you a thousand pound direct load capability.

The unit in the photo... Yech. Three relevant ways for tow equipment to kill a glider: easily reachable, locks on tow, dumps off tow during an argument that the glider's climbing hard in a near stall situation. The visible/top inside edges of the fixed arm look like hacksaw blades and the pivoting lever arm has square edges it shouldn't. Addressed easily enough with some filing.

Fix/Workaround for this issue...

- This release - in whatever application it's being employed - SHOULD be used in conjunction with a short, fat, wrap proof bridle. Doubles the load capacity at zero cost.

- It SHOULD directly engage a primary weak link - string loop or Bridle Link. Best configuration.

- Restrict the weak link loop diameter to the minimum which will cleanly clear the pin upon actuation. That should be the rule on weak links...



...anyway. This malfunction apparently requires "some manipulation" and my guess is that some manipulation will no longer be possible. How 'bout running the experiment and getting back to us?

I'd resume making this release available with notification about this issue and advisory. There are undoubtedly hundreds, probably thousands of these things in circulation, they've been used for at least a couple decades, we have ONE report of an inadvertent failure, and the alternative easily reachable, bent pin, Western crap that floods the Western market fails with such regularity that no one considers incidents worthy of mention and the kill track records are too long to keep in memory. Most other hardware choices are Russian roulette with one bullet and six chambers while the Kaluzhin - WITH the overlength weak link - is Russian roulette with one bullet and ten thousand chambers.

I currently see no Kaluzhin advisories on the Jack or Davis Shows. Good. Keep it that way. Fuck any English speaker who doesn't tune into Kite Strings. Jack degrades accessibility for nonmembers, bans anyone he doesn't want in his Living Room with zero justification, and is a major enemy of First Amendment principles. And the Davis Show is all of the above and not even publicly accessible.

If someone feels he MUST alert these cocksuckers to the issue in these venues then just post links to this topic on Kite Strings and let Jack and Davis delete them.