Weak links

General discussion about the sport of hang gliding
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Tad Eareckson
Posts: 9161
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=30908
Is this accurate?
Tiberiu Szollosi - 2014/03/14 12:47:12 UTC

That's what you call a real "Pro" Tow tooth removal assist Image
That's what I'd call a real Jack Show asshole crudding up the conversation 'cause he's incapable of saying anything halfway intelligent on any issue. (Go back two posts and check out P.S.)

Here's your original avatar, Tiberiu:

Image

Recognize it anywhere in this still:

40-40324
http://farm9.staticflickr.com/8394/8696380718_787dbc0005_o.png
Image

pulled from this video:

http://www.youtube.com/watch?v=-i4owd0akd0


uploaded the day before this news photo:

http://4.bp.blogspot.com/-bRrpHNa68iY/UQ6Pv9gRZyI/AAAAAAAAjTg/Hc22bx5122Q/s2048/20943781_BG1.jpg
Image

was taken?
Jack Axaopoulos - 2014/03/14 13:50:32 UTC

Definitely marketing hype.
Yeah. Marketing hype. You don't need to get the rabies vaccination series after being bitten by that rabid dog. Just take a couple of these Echinacea extract pills. You'll be fine.
I tested this theory once at over 2000 feet on tow.
- As opposed to testing this theory once at over 2000 feet OFF tow.
- Oh. It's a THEORY? Whose theory is it and on what data did he base it?
I caused a lockout with the intent to see how much force it took to break the weak link.
I could've saved ya some trouble there, Jack. The weak link will break when the tension it's feeling reaches its breaking point.
I was so out of line, the tow rope was strongly against my downtube...
No it wasn't.

36-05224
http://farm3.staticflickr.com/2857/11425450323_f9659e0462_o.png
Image

It's pretty much physically impossible to bring the towline in contact with a downtube.
...and building up insane pressure...
How insanely can the PRESSURE build up using THIS:

0:50
http://www.youtube.com/watch?v=JR_4jKLqrus


http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec
Mark Frutiger - 2013/02/08 19:12:21 UTC

Zack hit the lift a few seconds after I did. He was high and to the right of the tug and was out of my mirror when the weak ling broke. The load on the tug was not excessive as with a lockout, but I was not surprised when the weak link broke.
weakling?
...and I still had to add a violent pushout motion to get it to finally snap.
- You mean like THIS?:

http://www.hanggliding.org/viewtopic.php?t=14230
pro tow set-up
Ryan Voight - 2009/11/03 05:24:31 UTC

It works best in a lockout situation... if you're banked away from the tug and have the bar back by your belly button... let it out. Glider will pitch up, break weaklink, and you fly away.

During a "normal" tow you could always turn away from the tug and push out to break the weaklink... but why would you?

Have you never pondered what you would do in a situation where you CAN'T LET GO to release? I'd purposefully break the weaklink, as described above. Instant hands free release Image
Jim Rooney - 2009/11/03 06:16:56 UTC

As for being in a situation where you can't or don't want to let go, Ryan's got the right idea. They're called "weak" links for a reason. Overload that puppy and you bet your ass it's going to break.

You can tell me till you're blue in the face about situations where it theoretically won't let go or you can drone on and on about how "weaklinks only protect the glider" (which is BS btw)... and I can tell ya... I could give a crap, cuz just pitch out abruptly and that little piece of string doesn't have a chance in hell. Take your theory and shove it... I'm saving my a$$.
And then you just flew away? So how come you ran your test at over two thousand feet instead of under two hundred feet? Flat sack issues?

- So how much force did it take to break the Rooney Link? Insane pressure plus violent pushout motion? Is that English or metric?

- So you're saying that Wallaby, Quest, Florida Ridge, Lockout, Kitty Hawk, Ridgely, Cloud 9, Cowboy Up, Wannabe Ranch, all these motherfuckers who are pushing this Rooney Link rot are totally full of shit, right?

http://www.hanggliding.org/viewtopic.php?p=150666&highlight=#150666
pro tow set-up
Jack Axaopoulos - 2009/11/09 14:44:23 UTC

AT, your continual bashing in general and bashing of HG schools has gotten really old. AT parks have solid safety records, so what you say and reality seem to be quite far apart.

You dominate the ignore report here http://www.hanggliding.org/ignorereport.php
Ever ask yourself why???

You do nothing but bring negativity here. My finger is on the ban button.
This is your last warning.

If you continue rubbing everyone the wrong way with your harsh, know it all tone, you are out of here.
How have these solid safety records been going lately? Notice Mark Knight hasn't been doing a whole lot of posting lately? Aren't we gonna got another Jack Axaopoulos trademark:

http://www.hanggliding.org/viewtopic.php?t=14410
Wallaby fatality
Jack Axaopoulos - 2009/11/16 17:01:31 UTC

Nooooooooooooo! :cry:
http://www.hanggliding.org/viewtopic.php?t=14312
Tow Park accidents
Jack Axaopoulos - 2009/11/10 13:36:53 UTC

I still dont know if I buy into the stronger weak link hypothesis.
Ive broken weak links on purpose at altitude by banking up and pushing out abruptly. That is a mechanism I want to keep, not give up.
The downside is, you will get more weak link breaks while near the ground, early in a tow, or whatever.
BUT... you should be maintaining proper airspeed anyway, then its not an issue.
Fuck you, Jack.
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Tad Eareckson
Posts: 9161
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Re: Weak links

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=30908
Is this accurate?
Steve Seibel - 2014/03/14 16:54:02 UTC
Cool Breeze - 2014/03/14 02:37:24 UTC

Wallaby runs a clean operation. Safety first.
No quarrels with that, but as many have said, the statement about the weak link is not accurate.
Oh. They're publishing and teaching information which is pure unadulterated shit and has gotten tens of thousands of gliders crashed, many people seriously injured, and a good handful killed but they're running a clean operation and putting safety first.

Go fuck yourself Steve. I can't BELIEVE I ever wanted you over here.
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=30908
Is this accurate?
Mike Badley - 2014/03/14 23:44:57 UTC

Hey you guys laugh...
Yeah. I know EXACTLY what you mean.
...but in the old days...
Your USHGA Number is 49316. So just how much do you know about the old days?
...they...
They who? Gimme some names.
...would tow by wrapping the line around the basetube...
Bullshit. Hang gliders evolved out of water skiing. Nobody was doing crap like that. Well... We were doing crap like that with trainers out on the dunes when the wind was cranking and we were bored - but that wasn't exactly mainstream towing and we weren't bending any aluminum doing it.
...no weak-links...
Oh my GOD!!! NO LOCKOUT PROTECTION!!! How was it possible for ANYONE to survive? What would we have ever done if Donnell hadn't come along and taught us all how a weak link of one G or less would keep the glider from getting into too much trouble and when we stalled and crashed it would be entirely our fault?

I hope they at least had the common sense to be using backup loops and locking carabiners.
...just a friction hold on the rope.
Yeah, that was before Bobby Fucking-Genius discovered the bent parachute pin.

Friction hold on the rope or bent parachute pin?

http://www.hanggliding.org/viewtopic.php?t=21033
barrels release without any tension except weight of rope..
Bart Weghorst - 2011/02/25 19:06:26 UTC

I've had it once where the pin had bent inside the barrel from excessive tow force. My weaklink was still intact. The tug pilot's weaklink broke so I had the rope. I had to use two hands to get the pin out of the barrel.
No stress because I was high.
Pick one.
No pussy-tow-dollies neither.
- No Jim Keen-Intellect Rooneys to protect us from our own stupidity which we demonstrate by developing gear with no track records whatsoever.

- Yeah, that's 'cause it was pretty much all over water. So they used water skies and pontoons.

- Pussy-tow-dollies were in use by no later than mid 1983.
Just tie the rope to the bumper of the car and yank the guy up, hoping he didn't face plant.
You mean like:

Image
http://ozreport.com/pub/images/fingerlakesaccident2.jpg
http://ozreport.com/pub/images/fingerlakesaccident3.jpg
Image
http://www.youtube.com/watch?v=VYe3YmdIQTM

http://www.youtube.com/watch?v=u51qpPLz5U0

http://www.youtube.com/watch?v=bj-qBsETXPg
Aerotow launch faliure
Oliver Chitty - 2014/03/02
dead
When you got pulled up over the car, you let go and the rope slithered off the bar.
You're totally full of shit.
Man, I'm glad I didn't learn to tow that way....
- NOBODY learned to tow that way. Yeah, you can find reports of fringers doing stupid shit throughout the history of the sport... BUT:

-- You're presenting that crap as if it were mainstream.

-- It's still really hard to match the stupidity demonstrated by the crowd involved in the 2011/01/15 Shane Smith fatality - and those guys weren't fringers. Not much contest for the Zack Marzec fatality either - and those were the guys who'd spent twenty years perfecting aerotowing and they still haven't figured out why things went wrong.

- And here's how YOU learned to tow:

http://www.hanggliding.org/viewtopic.php?t=28759
Karen Schenck? (I think)
Mike Badley - 2013/04/02 05:08:22 UTC

I don't think a line over the bar would lock you out. I never liked the payout winch launches because you could never tell if you were going to just drift off the mount (because the brake was too loose) or rocket up with PIO's because the brake was barely paying out. Foot launching is so much better - and I use a Hewitt style bridle which has an over/under self adjusting rig. I also use Peter Birren's 'Link-Knife' set up which means a fresh weak link every tow.

Image
http://www.hanggliding.org/viewtopic.php?t=27396
Scooter tow faillure... or Never Land On Your Face
Mike Badley - 2013/04/02 05:20:24 UTC

I like this rig for foot launch - it's called a Hewitt Style and it also uses Peter Birren (Chicago) Link-Knife which actually severs the weak link every time. The weak link material is that industrial kite string (can't remember which size) which you make into a big loop that is doubled over through the eye of the tow rope and then fit through the shackle on the bridle. Works great.

Image
and still do. And I'd have WAY more confidence in the ability of someone who'd wrap a rope around his basetube than anyone who was still subscribing to Skyting Theory and using a Hewett Bridle much more than a couple days after the introduction to the public.

And anybody who was still using a Hewett Bridle after the introduction of the Koch two stage release in the mid Eighties is a total moron.

And I totally despise assholes who use something that "works great" and totally ignore the death and destruction that result when it fails miserably.
Steve Davy
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Re: Weak links

Post by Steve Davy »

I'm confused.

Michael Badley's photos show a closed bridle with a release at the apex. This video:

Hang gliding - Dan explains the double-threaded tow bridle system
http://www.youtube.com/watch?v=2dvr9P_w5VQ
jwm239 - 2011/05/02
dead

shows an opening bridle with a release near the keel.

Which one is a Hewett bridle?
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

They're both Hewett/Skyting/2:1 Bridles. Any bridle - the others being two and one point - can be opening/threading or closed. But only surface towers and idiots are using closed bridles.

Donnell's first bridle was a deadly Rube Goldberg job. I almost got my head taken off by one, 1984/05/12, kiting way the hell up from the dunes at Jockey's Ridge on a stationary payout winch in a thirty mile per hour southwest wind. You released by pulling a panic snap at your waist and, if you were lucky, that auto triggered another panic snap at the keel and the whole bridle/release assembly shot off and went down with the towline. People who weren't lucky got their gliders destroyed on the way back to the surface.

You needed enough tension to keep it from falling through the wires and/or control frame and weld you onto tow but not so much that the upper panic snap would take your head off. You were supposed to twist your body prior to pulling the release to take your head out of the line of fire but I guess that didn't register during the briefing.

At a thousand feet I was oscillating a bit and nervous and thought, "What the hell, let's see how this thing functions under tension." My helmet got slammed like you wouldn't believe. Without one I'd have probably been knocked unconscious and blown well out into the Atlantic.

I think the next version had a lanyard going to the keel release such that the sequence was reversed and then apex releasing - with the assembly staying with the glider - became dominant.

And all this time Donnell was studiously ignoring the fact that all the death and destruction he was predicting would be resulting from one point and one to one two point towing - that had been invented and was evolving in Europe - wasn't happening.

http://www.kitestrings.org/post125.html#p125
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

Hang gliding - Dan explains the double-threaded tow bridle system
http://www.youtube.com/watch?v=2dvr9P_w5VQ
jwm239 - 2011/05/02
dead
Dan Guido - 1:30

Now, again, what this does... It puts a two to one pull on the... on the pilot so that it might help, uh, it might help, um, deterring a lockout situation.
Catch the tell? If you string all that lunatic crap onto your glider it's supposed to make it impossible for it to lock out. And if you use it in conjunction with a weak link of one G or less it's supposed to make it impossible times two. But it didn't thirty-three years ago and it still doesn't now.

Dan was on the Skyting bandwagon within a half hour of the first publication hitting the mailbox. He knows things aren't adding up but he'll never be able to figure out why so he stutters through a semblance of an explanation and hopes for the best.

And the tell on THIS one?:

Wills Wing - Scooter Tow Resources
http://www.willswing.com/learn/scooterTow/#video
Steve Wendt - 08:26

But with the towline we use a standard weak link like we would for aerotow... Uh... This... In this particular case it's 130 greenline, 130 pound test.
Focal point of a safe towing system, the standard weak link like we would use for aerotow which puts everyone at about one G which is a good rule of thumb and keeps everyone from getting into too much trouble. He's got a pretty good idea that a single flavor of fishing line probably DOESN'T put everyone at one G and keep people...
Wills Wing / Blue Sky / Steve Wendt / Ryan Voight Productions - 2007/03

NEVER CUT THE POWER...

Image

Reduce Gradually
Increase Gradually
...so he pretends that he's using other flavors of fishing line to keep things proportional.

Dr. Trisa Tilletti eat up fourteen pages of the magazine on an intro to the focal point of safe towing systems, Steve Exceptionally-Knowledgeable Wendt covers the essence of the same disinformation in nine seconds. The time he spends covering the weak link from A to Z is four percent of what he uses to discuss his turnaround pulley.

The entirety of the junk he's putting on the glider and calling tow equipment gets under half the time the pulley does. And he dedicates only about about a second less to the "NEVER CUT THE POWER" message than the standard weak link seminar gets.
Steve Davy
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Re: Weak links

Post by Steve Davy »

http://www.youtube.com/watch?v=wdfLkTMi1eU


It appears that the tug driver is unconcerned that he's got a glider on tow and is flying like he doesn't have a care in the world. And the dude on the aft end of the line seems mystified by what's happening, just sort of waiting for things to work themselves out.

Is that what you see happening, Tad?
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

Much as I despise those motherfuckers down there (and everywhere else) this one - ignoring the Industry Standard crap equipment, which isn't really relevant here - isn't anything to worry about.

The tug finds a thermal to the right and makes an abrupt turn into it - as he should.

The glider - who's previously been working hard to stay in position - doesn't do shit in response to that move and gets lifted pretty good while pointed away from the tug. Semi-lockout, blows the Rooney Link, still doesn't turn into the lift.

Single surface, big training wheels, obviously a scared/nervous new kid with crappy training. But with the glider popping off in a hard roll at altitude there's no possibility of anything bad happening. He'll do better next time - if the weak link meets his expectation of being strong and reliable enough to avoid frequent breaks from turbulence, like this one at Zack Marzec Memorial Airport just up the road from Wallaby:

http://www.youtube.com/watch?v=bo1dDbb-bG4


doesn't. (Thanks for that find. One can't have too many of these.)
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://www.wallaby.com/aerotow_primer.php
Aerotow Primer for Experienced Pilots
Wallaby Ranch - 2014/03/31

If you fail to maintain the correct tow position (centered, with the wheels of the tug on the horizon), the weak link will break before you can get into too much trouble.
http://www.youtube.com/watch?v=wdfLkTMi1eU
Aerotowing - Weak Link Break

Shohei Asai - 2014/01/05 - Wills Wing Falcon 170 - Wallaby Ranch:

12-10013
Image

http://www.willswing.com/articles/ArticleList.asp#AerotowRelease
Aerotow Release Attachment Points for Wills Wing Gliders
Always use an appropriate weak link with a finished length of 1.5 inches or less.
http://groups.yahoo.com/group/skysailingtowing/message/4633
Weaklinks and aerotowing (ONLY)
Steve Kroop - 2005/02/10 04:50:59 UTC

Davis,

Your weak link comments are dead on. I have been reading the weak link discussion in the Oz Report with quiet amusement. Quiet, because weak links seem to be one of those hot button issues that brings out the argumentative nature of HG pilots and also invokes the "not designed here" mentality and I really did not want to get drawn into a debate. Amusement, because I find it odd that there was so much ink devoted to reinventing the wheel. Collectively I would say that there have been well over a 100,000 tows in the various US flight parks using the same strength weak link with tens of thousands of these tows being in competition. Yes I know some of these have been with strong links but only the best of the best aerotow pilots are doing this.
http://ozreport.com/12.081
Weaklinks - the HGFA rules
Davis Straub - 2008/04/22 14:47:00 UTC
Pilots must use weaklinks provided by the meet organizers and in a manner approved by the meet organizers. All weaklinks will be checked and use of inappropriate weaklinks will require the pilot to go to the end of the launch line to change the weaklink.

Weaklinks will consist of a single loop of Cortland 130 lb. Greenspot braided Dacron Tolling line and should be placed at one end of a shoulder bridle.
At the 2008 Forbes Flatlands Greenspot for the first time was used as the standard weaklink material (thanks in large part to the efforts of Bobby Bailey). We applaud these efforts to improve the safety of aerotowing by using a better weaklink material.
http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Jim Rooney - 2011/08/26 02:44:10 UTC

The "purpose" of a weaklink is to increase the safety of the towing operation. PERIOD.
Dr. Trisa Tilletti - 2012/06

Based on several decades of experience and hundreds of thousands of tows conducted by numerous aerotow operators across the county, the de facto standard has become use of a 260 lb. weak link made as a loop of 130 lb. green spot IGFA Dacron braided fishing line attached to one end of the pilot's V-bridle. It is a de facto standard, because it works for most pilots and gliders and is usually near the USHPA recommendation of a nominal 1G weak link for most pilots.

We want our weak links to break as early as possible in lockout situations, but be strong and reliable enough to avoid frequent weak link breaks from turbulence. It is the same expectation of performance that we have for the weak links we use for towing sailplanes.
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

Falcon 3 170 max certified operating weight:
- 268 pounds
Towline tension limitation of an unfuzzed Wallaby Link on a two point bridle:
- 226 pounds
Minimum legal weak link rating:
- 0.80 Gs
Wallaby Link on a Falcon 3 170:
- 0.84 Gs
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