Weak links

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Scot Trueblood - 2013/07/05 14:25:54 UTC
Paradise Hang Gliding, Inc.
Bonita Springs, Florida

We recently started using the weak links from towmeup and are very happy with them.

Why? Do they meet with your expectations of breaking as early as possible in lockout situations but being strong and reliable enough to avoid frequent breaks from turbulence?

Are you happy with the airbags in your car because they don't deploy when you're driving to the mall or swerving to miss a squirrel but blow instantly whenever you drive into a telephone pole?

If you tie the pre-cut ones as closely as possible to being identical length, it is easy to tell if they have been over-stressed and close to breaking from wear. We simply rig at least two weaklinks to our drogue (usually three or four). When one has been stressed, it stretches noticeably. You can simply remove it, or just not use it until removed.

Sounds to me like you're going to extraordinary lengths to avoid weak link successes. Have you ever considered the ramifications of that if you suddenly find yourself in a nasty lockout and the weak link doesn't succeed when it's supposed to?

I will suggest that many weak link breaks are due to flying with a worn or previously stretched link. Flying with multiples, in our case, helps prevent this, as one can simply gauge the length and easily spot a stretched one.

I will suggest that you're still using and thinking of a weak link as a lockout protector - especially seeing as how you haven't denounced the crap that Stuart has on his idiot website - and you're using a weak link that's seeing tension pretty close to its breaking point and way over its Safe Working Load under normal conditions.

And I will suggest that you use a weak link that blows at about one and a half times the max certified operating weight of your glider. Call the glider five hundred pounds, use a weak link that blows at 750 towline. You'll never have a weak link break, the weak link will never stress out, and as long as it doesn't get abraded you can use it forever.

We are platform towing using a three-string release bridle and have no trouble, not sure how this would work with a barrel release.

Only about half as well as it would work with two barrels with a bridle between them.

If I were using this for aerotowing, it would seem wise to keep a fresh link to compare with and examine for stretching.

You haven't told us anything about Gs or pounds or stated that you're using your weak link as an overload protector and your weak links are too light.

Also, in our case salt water and UV play a major role in premature wear.

I doubt it. You should be using Dacron and Dacron doesn't care much about UV or salt water. If it did there'd be a lot of sailboats in a lot of trouble.

We keep plenty of weak links handy, and if there is the slightest doubt, it is much easier to replace a link rather than give a customer another flight.

- Or kill one, along with the pilot and glider, and have to try to replace all those items. (Like what happened at Hang Glide Chicago on 2005/09/03.)

- Your weak links are too light. Ask your glider manufacturer what you should be using (and why the motherfucker doesn't have that information in the owner's manual).

- So you'd be pretty on board with THIS:

Tost Flugzeuggerätebau

We recommend that the weak link insert are replaced after 200 starts: An insert exchanged in time is always safer and cheaper than an aborted launch.

(Think you've adequately considered the "safer" component of that equation?)

Another observation is, as regards knots and methods of attachments: The double grapevine (or double fisherman's knot) is really the only knot to use.

What if you didn't use a knot? What's your objection to using Tost weak links:



...or Tad's:

http://www.flickr.com/photos/aerotowrelease/8305364731/

http://www.flickr.com/photos/aerotowrelease/8306429930/

http://www.flickr.com/photos/aerotowrelease/8305393601/


Shear Links? Afraid Rooney won't grant you permission?

The link should always break at the knot. We experimented with using a larkshead to attach it to our metal link at the end of the drogue, but found that it greatly increased the chances of breaking the link when it seemed unnecessary, as this configuration breaks the line where it passes around the link, away from the knot. Simply looping it onto our link with no other knots works far better.

Oh. When it DOESN'T BREAK that's far BETTER. Are you sure?

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks

Jim Rooney - 2013/03/05 01:32:20 UTC

Btw, it's nothing to do with you "counting" on the weaklink breaking... Its about me not trusting you to hit the release.
If it were only about what you want, then you could use what you like.
You want the strongest weaklink you can have.
I want you to have the weakest one practical.. I don't care how much it inconveniences you.
I don't trust you as a rule. You Trust you , but I don't and shouldn't.

Is the asshole on the boat OK with this?

I have now done hundreds of tandem tows without breaking a link, sometimes with heavy students and fairly high towline tension such as when hitting thermals.

Wanna express that in pounds?

Happy Landings...!

You too. And let me be the first to thank you for all your participation in the Zack Marzec discussions.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Damien Gates - 2013/07/05 14:30:27 UTC

Davis Straub - 2013/07/05 14:12:25 UTC

I didn't feel that my glider was in danger of being over stressed. I would have pulled the barrel release but the weaklink broke before I could react.

And that is my point (well one of them), ultimately you were not relying on the weaklink to save you.

Don't tell him that. The more that motherfucker relies on his Davis Link, pro tow bridle, and Aussie Method to save him the happier I am.

Damien Gates - 2013/07/05 14:34:44 UTC

Mike Lake - 2013/07/05 13:50:12 UTC

An excellent post. Thank you.

Thank you

Just make sure they're not TOO excellent or you'll get the thread locked down.

Davis Straub - 2013/07/05 15:06:10 UTC

Scott you might look more closely at the results shown in the spread sheet and the testing video from Tracy and Lisa.

Yeah Scot. And then ask Mark and Jim how come they didn't use the Wrap and Tie Method of installing the weak links for their tests so they could get loops that held to twice the test strength of the string.

Davis Straub - 2013/07/05 15:11:23 UTC

I don't think that anyone is absolutely relying on their weaklink to save them.

Bullshit.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3391
More on Zapata and weak link

Paul Tjaden - 2008/07/22 04:32:22 UTC

I have never had a lockout situation happen so quickly and dramatically and had no chance to release as I have always thought I could do.

Everybody and his dog knows from experience at altitude that that Industry Standard crap with which you assholes flood the market will be totally useless in real emergencies and that the only way they're gonna get off is if somebody pulls or cuts something on the other end or something breaks in time.

I had the option of pulling the pin.

Bullshit. You had no more option than Paul Tjaden, Marc Fink, Holly Korzilius, or Steve Elliot.

But I have relied on my weaklink to save me when I've been pulled out of the cart and hit the ground, because it worked before I could get to my barrel release.

Bullshit.






You had all fuckin' day to "get to" your barrel release right there on your shoulder or the brake lever "within easy reach" on the downtube. Neither of your hands ever left the basetube because with that total crap equipment the only option you had was to stay on the basetube, wait for the impact, and pray that your head missed the keel - which would've been the precise opposite of what a lot of other people would've been praying for.

I would better rely on a mouth release in that case.

- Describe a case in which you or any other asshole WOULDN'T be better off relying on a "mouth" release - asshole.

- Yeah, but it's been about a month shy of nine years since that happened and you're probably never gonna be in another critical situation like that so just keep using crap releases and waiting for the lockout forces and impacts to blow your Davis Links. And do try to keep a camera running for all your tow launches.

So I am relying on my weaklink to save me before I can get to the barrel release, yes.

And please try to rely on your helmet to save you before you can apply your bicycle brakes.

And I am relying on the weaklink to break before I get too far out of whack too quickly behind a tug so that it breaks before I get to my barrel release.

Yeah, just like Lauren says. Keeps you from getting...

http://www.youtube.com/watch?v=k9fQuDzFuCE


...too far out of whack. And if you can't get too far out of whack there's really no way anything bad can happen to you.

Recently I have pulled the pin they times when way too high on a tug that was too near the ground, but I was not out of whack, just trying to save the tug pilot. I was fine.

What? Don't tell me you were using one of those two hundred pound Morningside Links...

http://ozreport.com/forum/viewtopic.php?t=15716
weak links

Davis Straub - 2009/04/26 22:05:31 UTC

Tad doesn't agree, but the rest of us no doubt do, that we are in a partnership with the tug pilot, and that he needs to be protected also, and therefore our weaklink has to be less than his.

...which exceed and override the tug's weak link and have the potential to stall him or nose him into the runway. Pretty fuckin' callous if you ask me.

[deltaman]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Hey, what the fuck !!?:

Sure, the weaklink will break... if you don't hit the ground first... but it's going to be a seriously dramatic event when it does... which too may precipitate you flying into the ground. Weaklink breaks post lockout account for a high percentage of unintentional wingovers... usually low altitude wingovers... some of which are not survivable.

[Tad Eareckson]

Yeah, they're paving the way for two hundred pound weak links and trying to pull their feet out of their mouths and...

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Jim Rooney - 2013/02/17 10:37:47 UTC

I'm not sure who you're arguing with Zack, but it's sure not me... cuz man... you've got some pretty big hangups mate.

Ra ra ra... burn the greenspot!!!!
Get real man.
You think that's all we use?
Hell, just in this thread, you seem to have missed the 200lb orange links.
Ah, but your strawman argument lives and breaths by your black and white hyperbole.
When you come back to reality, let me know.
Till then, I'm sick of it.

...extract themselves from the corners they've been painting themselves into for a couple of decades and present themselves as tireless innovators and promoters of positive change.

"Well yeah, Rooney Links can HELP - but you're probably gonna slam in after they do anyway... So you have my permission to use this two hundred - for a probationary period anyway. I did extensive testing on it for a month with Mark Knight and we found its tolerances and performance to be within our standards.

"Tad-O-Links? BWA HAHAHAHAAHA! You've gotta be kidding me."

Don't let them get away with ANYTHING. The war ain't gonna be over with a bunch of gliders permitted to tow at 1.2 Gs. This sport has been hijacked and ruined by a lot of really evil people who really need to have their backgrounds and histories exposed and reputations destroyed.

I can't wait to get this one under control so I can get back to demolishing Pat Denevan and his junk equipment, pitch limiters, and cover-up approach to hang gliding safety.

The GoPro camera and YouTube are two of the greatest things that have ever happened to this sport.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Jim Rooney - 2013/07/05 15:48:58 UTC

Hey Tex.
No one said anything about lockouts.
Well, you just did.
So enjoy your argument... just remember, you wanted to have it

He doesn't need to have any arguments. What he mostly needs to do is sever diplomatic relations with you sleazebags.

Davis Straub - 2013/07/05 16:02:03 UTC

Actually, Jim, this was in the article:

My experience in weak links breaking during lock out is that it does not happen very fast.

There are tons of little gems in that article. It would take a year to deal with them all properly. And you motherfuckers made a big mistake blackballing me out of the sport. I was pulling so many punches before.

Damien Gates - 2013/07/05 18:38:18 UTC


and this

I have induced a lockout purposely...

then this

if you have a close to lock out

so three times no one said anything about lockouts

Damien Gates - 2013/07/05 18:40:22 UTC

Davis Straub - 2013/07/05 15:11:23 UTC

I don't think that anyone is absolutely relying on their weaklink to save them.

The only reason I raised the issue was because I thought some people are absolutely relying on their weaklink to save them. If not then good, REAL GOOD!

Nope.

Safe skies all!

No fuckin' way.

Jim Rooney - 2013/07/05 18:46:53 UTC

Fair enough.

What the fuck would you know or care about fairness?

Yup, the way he mentions it at the very minimum brings up the topic.

I do want to highlight the fact that a weak link should never be associated (even indirectly) with saving you from lock out... It doesn't.

I can't say that I'm a fan of strawman arguments, and this one's a bit of a reach, but I'll concede it.

Anybody who gives a rat's ass about what you are or aren't a fan of and/or what you will or won't concede is a total moron. Whatever you say for the rest of your life will have been flatly contradicted by something else you carved into granite at another time.

I don't agree with him, but you're right... Mark put it on the table.
Sorry Tex

I'da thunk you'd have gotten everything sorted out in all that quality time you spent with your arm breaking colleague. Not that...

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?

Jim Rooney - 2011/08/26 02:44:10 UTC

I find no disagreement in the professional community as to such.

...there should've been anything in need of sorting out anyway.

Now as for the over the top opinion... they very much have saved some people, quite inadvertently, from lockouts.

NO weak link has ever saved anybody from a lockout. A glider locks out, a string breaks, and a glider is or isn't high enough to recover. It's like saying a stretch of highway with no trees along it saved a driver who fell asleep at the wheel.

They've saved me the trouble, on many occasions, from giving people the rope.

- What people?

- How come we're not seeing the videos or hearing them sing the praises of their Rooney Links? It seems like most of the discussion in this thread is - as usual - how to not experience a Rooney Link break.

- If the:

-- people who were saved by their Rooney Links were too incompetent to launch without getting into low level lockouts they couldn't abort why were you towing them and who signed them off?

-- lockouts were inevitable because they were towed into strong thermals or dust devils why were you towing them into strong thermals or dust devils?

- Davis says:

Davis Straub - 2013/07/05 15:11:23 UTC

I would better rely on a mouth release in that case.

So were you ensuring that they were outfitted with the best equipment possible? Or were you towing them on the usual Industry Standard crap like they sell at Quest, Ridgely, and Manquin?

Should they be counted on to do so?
I couldn't care less.

Yeah Jim, It's really hard to find people who...

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks

Jim Rooney - 2013/03/08 02:29:51 UTC

I couldn't care less.

Jim Rooney - 2013/03/11 02:21:14 UTC

I couldn't care less if you like my answers or not.

...care any less than you do.

Do they do it?
You better believe it.

Do they do it in time, all the time?
No way in hell.

So what you're saying is that using a weak link for lockout protection is a dice roll.

And it seems to me that whether or not you survive a lockout - whether terminated by a:
- Rooney, 1.0 G, 1.5 G, or 2.0 G weak link
- glider or tug release
is entirely an accident of altitude. Right?

I know people that get off tow by purposefully breaking the weak link.

I know people with crappy approach skills who stop their gliders by flying them into ponds, fences, and trees at the far end of the field.

Aerotow lockouts are exponential... that little piece of sting is going to let go.

I got news for ya, shithead. When things are going exponential it doesn't matter much what kind of sting is being used. When a 300 pound glider capable of pulling at least six Gs is going in a direction significantly different from what a nine hundred pound Dragonfly is heading it doesn't make much difference what kind of sting you're using to tie the two planes together.

Will it let go before you smash into the ground?
Who knows?
Depends how high you are.
But given enough time... it's going to let go.. and it's going to be dramatic when it does.

Translation... It's totally moronic to try to use or think of a weak link anywhere in or below the legal range in terms of something that keeps the pilot - or glider - safe. The weak link is ONLY gonna be of use to a glider that's:
- being overloaded; and
- considerably high

My personal opinion?

Not interested in opinions.
Interested even less in personal opinions.
If YOUR personal opinion is that Mount Rainier is in Washington I'm gonna start looking for it in Key West.

If you lose the weaklink before you release, you released too late.

If your release actuator is on your downtube or shoulder you're gonna lose the weak link, anything remotely resembling the direction in which you had been headed, a lot of altitude, and quite possibly your life.

And any dumb fuck tug driver who tows people on the kind of shit you sell them is SCUM. And any dumb fuck tug driver who tows people on the kind of shit you sell them and deludes them into thinking that a Rooney Link will INCREASE their safety margins deserves to be stripped naked, smeared with honey, disemboweled, and staked to an anthill.

Pick your poison carefully.
Jim

Capital idea...

The Press - 2006/03/15

The Civil Aviation Authority (CAA) is urgently pushing for new hang-gliding industry standards after learning a hang-gliding pilot who suffered serious injuries in a crash three weeks ago had not clipped himself on to the glider.

Extreme Air tandem gliding pilot James (Jim) Rooney safely clipped his passenger into the glider before departing from the Coronet Peak launch site, near Queenstown, CAA sports and recreation manager Rex Kenny said yesterday.

However, he took off without attaching himself.

In a video, he was seen to hold on to the glider for about fifty meters before hitting power lines.

Rooney and the passenger fell about fifteen meters to the ground.

I'm always telling people the same thing myself.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Jim Rooney - 2013/07/05 18:49:13 UTC

Oh, and one thing definitely not to be missed here (especially as the tired old arguments get going)...

I'll bet if you:
- knew what the fuck you were talking about; and/or
- didn't totally suck at communicating it
there wouldn't be any of these tired old arguments you find to be so burdensome. But since you're O for 2...

...is that if you get close to lockout, replace your weaklink.

Yeah?

- What IS "our" weak link? You tested line from 130 to 300 pounds and 200 is now an "accepted standard".

- What's the towline tension required to put a glider into a lockout?

-- I've measured normal towline tension behind a 914 Dragonfly as 125 pounds.

-- What do you think the glider's gonna do if it feels 125 pounds pulling sideways on it? Autocorrect the way Hewett assures it will?

-- You're calling a loop of 130 154 pounds (although those of us who test it on BRIDLES - rather than quick links - tend to center around 130). On a one point bridle with the towline pulling sideways at 125 pounds this 154 pound Rooney Link of yours is feeling 63 pounds or 41 percent of its breaking strength.

- And you're not even talking about a lockout. You're talking about replacing the weak link if you get CLOSE TO a lockout. So if you can lock out at normal towline tension how much tension do you need to get CLOSE TO a lockout? I'm guessing a lot less.

- So if we can get close to a lockout with less than normal tow tension shouldn't we be replacing the weak link every flight? Hell, shouldn't we be continuously replacing the weak link all the way up?

- What about turbulence? The sweet spot for a weak link is when it meets our expectations of breaking as early as possible in lockout situations but being strong and reliable enough to avoid frequent breaks from turbulence. So turbulence should stress the weak link about the same as a lockout. So shouldn't we replace the weak link after flying through turbulence?

- What about propwash? No, wait...

http://ozreport.com/forum/viewtopic.php?t=27494
The exciting bits

Jim Rooney - 2012/05/28 11:49:58 UTC

Guys
Your questions hold the answers.

What you're writing about and what your seeing are two very different things.
Your theories are what are doing you in.

What you're talking about is coming out of the cart too early and not having enough flying speed.
What you're watching is Davis coming out of the cart at Mach5.
He is absolutely no where near coming out too slow!

I've said it before, I'll say it a million times... a 582 tug is NOT the same thing as a 914.
Using 582 techniques on a 914 will put you in the shit.

All this "hang onto the cart till it's flying" stuff is fine for 582s. It is NOT for 914s.
Why?
In a word... propwash.

I'm not kidding.
It amazes me how people underappreciate the propwash. It's an afterthough... a footnote.
Let me tell ya guys... on a 914, it's the #1 factor when you leave that damn cart.
You SLAM into that propwash.

I'm towing out here in the desert at the moment. Out here, like it or not, you get to see the propwash. You see it in a big way. Even when we're towing on the pavement, you get to see it. It sucks and you know exactly where it is... because it's a big old cloud of dust and rocks. We insist on our passengers wearing glasses because of it (we provide them if they don't have their own).

Crosswinds of course make a huge difference. But again, we see the propwash... it's clear as day. Sometimes we can even steer around it (that's an other topic though).

The reason I make such a big deal about the difference between the 582s and the 914s is because behind a 582, you're still on the ground when you hit the propwash. You're rolling on the cart and you roll right on through it. No big deal.

So when you "wait till you're lifting the cart"... you're WELL BEYOND the propwash.
When you exit at Mach5, it's no big deal.

Now, when you do this behind a 914... it's a huge deal.
As I said, you slam into the prop wash.

And you're wondering why you're breaking weaklinks????
Are you kidding me?

Think about it... you're going a million miles an hour under huge (relatively speaking) line tension as you come blazing out of the cart struggling to "stay down"... as you slam into turbulent air. Hell yes you're going to break weaklinks. That's what they're there for!
You're subjecting them to massive loadings.
(The shock loading a weaklink sees as you hit the propwash is far greater than people appreciate)
That's why we have them... they're doing their job.

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


We WILL be replacing our Rooney Links after slamming into the brick wall of propwash at a million miles an hour under huge (relatively speaking) line tension.

- Who's gonna stress a Rooney Link more? A 200 pound glider coming close to a lockout or a 350 pound glider bouncing through turbulence?

You've stretched it and it's far weaker.

Think of all the corn fields you could fertilize if you diverted just two or three percent of the shit you spew out in hang gliding to agriculture.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Damien Gates - 2013/07/05 19:10:45 UTC

No straw man argument here... I was never arguing anything from the OP just adding something to the discussion. The 'disagreement' came later when Davis mentioned those unnamed others...

Funny how the discussion transpired as it did because I drafted this earlier in the night but never posted it as I got distracted:

I don't think there should be an 'argument'... I believe it is just a safer way to describe what is happening, it wasn't my idea, obviously better minds described it to me.

On that note, just some background in my motivation with this topic: Mainly for inexperienced or ab initio tow pilots they appear to me to be often under the impression that the main purpose of a weaklink is to protect them from a lockout.

Just the...

http://www.wallaby.com/
Wallaby Ranch

Welcome to the one and only Wallaby Ranch!

Wallaby Ranch is the first and largest aerotow hang gliding flight park in the world.

The very concept of a hang gliding school built around two-place in-air instruction was invented here. It was in 1991 when Malcolm Jones, founder and owner of Wallaby Ranch, outfitted tandem hang gliders with wheels for easy take-offs and landings, which in conjunction with aerotowing revolutionized hang gliding instruction and paved the way for a better, safer, and more enjoyable way of learning how to fly.

We have more experience aerotowing hang gliders than any other outfit. No one comes even close. Malcolm is by far the most experienced tandem hang gliding pilot in the world, and has more than 30,000 incident-free tandem flights under his belt.

Wallaby Ranch enjoys a stellar reputation as one of the best hang gliding schools in the nation and around the globe. Numerous 'big name' hang gliding pilots recommend Wallaby Ranch as the best and safest place to learn how to fly hang gliders.
---
A weak link connects the V-pull to the release, providing a safe limit on the tow force. 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.

...ab initios?

I have observed on many occasions pilots locking out on tow and they get given the rope OR after things going real bad the weaklink breaks. They will describe how in the first scenario the weaklink didn't break 'but should have'...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3276
Ridgely Sunday!

Chris McKee - 2008/05/26 12:57:18 UTC

Expecting to add to my long list of sled rides this year, I was surprised just how much thermal turbulance was out there on tow. At 2200 feet, I watched as the Tug rocketed up and my glider joined the space shuttle launch a few seconds later. I fell out of the thermal in a hard right turn and knew I had no chance to get back wings level. As I reached for my release, the weak link snapped (AS IT'S SUPPOSED TO) and suddenly I was off tow.

...or 'the weaklink didn't want to break' even though they were locked out.

Donnell Hewett - 1985/04

And concerning the three other USA fatalities - those involving beginner/novices and apparent lockouts - I would like to know what these inexperienced pilots were doing at altitudes high enough to lockout? Were they being pulled so fast that a lockout which started at only at three to six feet forced them into an arc high enough to roll over? If so, why were they being pulled so fast? What strength of weak link were they using that it didn't break when being pulled that fast?

http://ozreport.com/9.009
2005 Worlds

Davis Straub - 2005/01/11

Rohan Holtkamp did an analysis of the accident, in particular the bridle and weaklink, which never broke.

They fail to realise that when it went bad the tug pilot would have slowed up to reduce tension to help and manoeuvre the tug to assist as well, which to some extent would offset their separation from the tug (stopping a weaklink break) BUT did not give enough to reduce tow tension to regain control from a lockout.

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks

Davis Straub - 2013/03/06 18:29:05 UTC

You know, after all this discussion I'm now convinced that it is a very good idea to treat the weaklink as a release, that that is exactly what we do when we have a weaklink on one side of a pro tow bridle. That that is exactly what has happened to me in a number of situations and that the whole business about a weaklink only for the glider not breaking isn't really the case nor a good idea for hang gliding.

I'm happy to have a relatively weak weaklink, and have never had a serious problem with the Greenspot 130, just an inconvenience now and then.

The scary part for me is they basically 'by default' are just waiting for the weaklink to break, because that is what they believe WILL happen...

Matt Taber - 2009/07/12

If properly used, there is a minimum of three ways to release from the towline. Do not depend on any of these ways by themselves and fly with a back up. The first release is the primary release which under certain situations may fail, second, is the secondary release that works most of the time, if all is set up correctly, and third, the weak link which will break under the right load. You should also fly with a hook knife that will allow you to cut the line if need be.

...when really they should be attempting a release (preferably early) IMO, especially if at a critical altitude (low).

And if we can't afford to take a hand off to effect an easy reach....

http://www.hanggliding.org/viewtopic.php?t=14230
pro tow set-up

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$$.

The way we describe weaklinks and their purpose and lockouts needs special care...

Towing Aloft - 1998/01

A weak link is the focal point of a safe towing system.

...that is all.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Damien Gates - 2013/07/05 19:10:45 UTC

On that note, just some background in my motivation with this topic: Mainly for inexperienced or ab initio tow pilots they appear to me to be often under the impression that the main purpose of a weaklink is to protect them from a lockout.

They APPEAR TO YOU to be often under the impression that the main purpose of a weak link is to protect them from a lockout because that's what ALL OF THEM:
- have been TAUGHT for the past thirty years
- are being TAUGHT now
- will continue to be TAUGHT for the foreseeable future
by assholes like - from just this thread - Davis Straub, Mark Knight, Jim Rooney, Stuart Caruk, and Scot Trueblood.

And if you read this thread - currently stalled/dead at 32 posts - carefully you'll notice that there ZERO real discussion a of the ACTUAL PURPOSE of the weak link. And you yourself are a big part of the problem. You say:

Damien Gates - 2013/07/05 12:29:18 UTC

I do want to highlight the fact that a weak link should never be associated (even indirectly) with saving you from lock out... It doesn't. What it does is possibly save your glider from failure because of the lock out you are in OR getting dragged along the ground behind a tow vehicle.

Already you're talking and thinking about the weak link as an emergency release. It ain't.

And then:

You can enter and remain in a lock out without ever exceeding the strength of your weak link (1g).

A one G "weak link" IS NOT being used to "possibly save your glider from overload". A one G weak link is a classic Hewett lockout and stall protector. A one G Hewett Link is what very clearly provided Zack Marzec protection from a high angle of attack and killed him 22 weeks ago.

Speaking of Zack Marzec... Anybody notice that in this thread:
- the:
-- only Zack return is Zack C?
-- word "stall" appears not once?
- there is no mention of a:
-- negative consequence of coming off tow?
-- minimum safe weak link strength?

And we have:

Mark Knight - 2013/07/04

My calculations and test suggest the 200 lb. is right for me. I weigh 185 pounds, fly a T2 154 (75 lbs), and my harness fully loaded is 35 pounds. Total all up flying weight is 185 + 75+ 35 = 295 lbs. Times 1.4 = 413. I use Pro tow barrel release so divide by 2 = 206.5. I feel the White and purple is a good fit for me.

That's total rot.

- A weak link is not:
-- "RIGHT" for a person
-- even "RIGHT" for a glider

- In our game the closest thing we have to being "RIGHT" is almost always the heaviest weak link our release can safely handle.

- ANYBODY who selects a weak link as a "good fit" to his flying weight is - by definition - trying to use it as a lockout protector / emergency release.

We can see the pattern right here.

- The Industry knows that it needs to get weak links up to two hundred pounds to reduce the probability of another Zack Marzec invisible dust devil fatality but it's still gonna sell the weak link as a lockout protector / emergency release and deny that popping off tow can ever be anything more serious than a minor, easily dealt with inconvenience.
---
P.S. 2013/07/06 21:44:00 UTC

Should've included THIS:

Most reliable sources believe that a weak link should be sized so that it breaks at 75% to 100% of the in-flight load. Light pilots need weak links that break with a lower force than heavy solo or tandem pilots.

from idiot fucking Stuart TowMeUp Caruk's website.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Mark Knight - 2013/07/04

I really like the links being sold at towmeup.com. They test every spool at different areas to assure consistent product is being used. The:
http://www.towmeup.com/weaklink.html
website has good information. I recommend everyone go read it.

Hey Mark...

Did you read THIS part:

THERE IS A HUGE MISCONCEPTION IN THE PILOT COMMUNITY RELATED TO HOW STRONG A TIED WEAKLINK ACTUALLY IS IN PRACTISE! KNOWING WHAT LOAD YOUR WEAKLINKS WILL WITHSTAND BEFORE THEY BLOW OUT IS CRITICAL TO FLIGHT SAFETY. A WEAKLINK THAT BLOWS OUT PREMATURELY CAN IN MANY CASES BE WORSE THAN USING NO WEAK LINK AT ALL!

These two sentences that Stuart had in enlarged, bold, caps locked letters?

You think maybe you could crash a lot of gliders by handing out loops of 130 pound Greenspot stall and lockout protectors and telling everybody they blow at 260 pounds - twice their actual capacity?

Maybe you should get in touch with your former student...

http://www.youtube.com/watch?v=VYe3YmdIQTM


...and get his opinion on the issue.

Davis Straub - 2013/07/04 13:47:57 UTC

From:
http://www.towmeup.com/weaklink.html

A popular misconception uses a very common 135 pound test green spot trolling line...

Hey Davis...

What do the two sentences that Stuart had in enlarged, bold, caps locked letters IMMEDIATELY ABOVE that except say? Since Stuart had them in enlarged, bold, caps locked letters isn't it a fairly safe assumption that he considered them a lot more important than some of the stuff you quoted?

Why did you leave them out? Is it because...

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Davis Straub - 2013/02/13 15:45:22 UTC

We have no agreement that a stronger weaklink would make it safer.

...we have no agreement that a stronger weaklink would make it safer?

A popular misconception uses a very common 135 pound test green spot trolling line. In fact the myths associated with this product are so strong we no longer carry it.

Isn't that the better weaklink material you've been forcing everyone up on...

http://ozreport.com/12.081
Weaklinks - the HGFA rules

Davis Straub - 2008/04/22 14:47:00 UTC

Here is the requirement from the 2007 Worlds local rules (which I wrote) for weaklinks:

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.

...in an effort to improve the safety of aerotowing?

Isn't that the better weak link material Zack Marzec was using...

http://farm9.staticflickr.com/8394/8696380718_787dbc0005_o.png


...in an effort to improve the safety HIS aerotowing? How'd that work out for him?

Here's how the myth goes.

Many, many pilots believe that if you take a 135 pound weaklink line and tie it in a loop that it will break at 270 pounds. The logic is that there are two parallel load paths sharing the load, each one capable of withstanding 135 pounds. They miss the fact that any properly tied weaklink will ALWAYS fail at the knot. The line is pulled tighter and tighter at the knot and should break right at the knot every time.

Depending on the knot used the line will break at 40-60% of its rated strength. Typically a weaklink tied with a double grapevine will break at slightly over the rated strength of the line.

Isn't that the myth that Quest Air - which has been involved in perfecting aerotowing for twenty years - was...

http://www.questairforce.com/aero.html
Aerotow FAQ
Equipment and Accessories
Weak Link

Most flight parks use 130 lb. braided Dacron line, so that one loop (which is the equivalent to two strands) is about 260 lb. strong - about the average wing load of a single pilot on a typical glider. For tandems, either two loops (four strands) of the same line or one loop of a stronger line is usually used to compensate for nearly twice the wing loading. When attaching the weak link to the bridle, position the knot so that it's hidden from the main tension in the link and excluded altogether from the equation.

...perpetrating on all gliders - along with most (all) flight parks - for twenty years?

P.S. I amended a P.S. to the previous post.

[Tad Eareckson]

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3380
Lauren and Paul in Zapata

Lauren Tjaden - 2008/07/21 14:27:04 UTC

Zapata has delivered as promised, day after day with howling winds and good lift, where flights of over 100 miles (and much more) are possible.

Yesterday I chased Paul again. The tow rope weak link broke when Paul locked out and the weak link he got from Tad did not break. Russell said it was about the worst he has ever had his tail pulled around. Anyhow, I would advise against those weak links, though Tad's barrel releases do seem better able to release under stress. After Russell got a new rope and Paul recovered, he was late leaving and got trapped under some cirrus.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3391
More on Zapata and weak link

Paul Tjaden - 2008/07/22 04:32:22 UTC

The lockout Lauren mentioned was precipitated by my attempt to pull on more VG while on tow. I have done this before but this time the line wouldn't cleat properly and while I was fighting it, I got clobbered and rolled hard right in a split second. There was a very large noise and jerk as the relatively heavy weak link at the tug broke giving me the rope. I recovered quickly from the wingover and flew back to the field to drop the line and then relaunched after changing to a normal weak link. I have never had a lockout situation happen so quickly and dramatically and had no chance to release as I have always thought I could do. Had the tug's link not broken, things could have gotten very ugly very fast. I still don't like weak links breaking when they shouldn't, but the one I was using was way too strong.

Paul Tjaden goes up on, if I recall correctly, a 432 pound Bridle Link - a little heavier than a double loop of 130 pound Greenspot - which puts him at 1.4 Gs flying weight or 1.2 Gs max certified operating weight.

This killer Tad-O-Link:
- fails in its primary function of keeping Paul from locking out while he's flying:
-- in violent thermal conditions
-- with one hand and inaccessible releases
- breaks Russell's tow mast breakaway protector after almost killing Russell
- destroys Paul's chances of setting a five hundred mile world distance record

Paul vows never again to question Jim Rooney's Keen Intellect and returns to the proven system with a huge track record forever.

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?

Jim Rooney - 2011/08/26 08:24:31 UTC

Thought I already answered that one... instead of quoting myself (have a look back if you don't believe me), I'll just reiterate it.

I don't advocate anything.
I use what we use at the flight parks. It's time tested and proven... and works a hell of a lot better than all the other bullshit I've seen out there.

130lb greenspot (greenspun?) cortland fishing line.
In stock at Quest, Highland, Eastern Shore, Kitty Hawk Kites, Florida Ridge, and I'm pretty sure Wallaby, Lookout and Morningside.
Not sure what Tracy up at Cloud Nine uses, but I'll put bets on the same.

Did I miss any?
Is it clear what I mean by "We"?
I didn't make the system up.
And I'm not so arrogant to think that my precious little ideas are going to magically revolutionise the industry.
There are far smarter people than me working this out.
I know, I've worked with them.
(Bobby's a fucking genius when it comes to this shit... for example.)

Flight parks coast to coast are in lockstep using only the very safest of weak link material - 130 pound tournament fishing line which works a hell of a lot better than all the other bullshit Rooney's seen out there.

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?

Davis Straub - 2011/08/26 14:04:52 UTC

We had six weaklink breaks in a row at Zapata this year. Russell Brown (tug pilot, tug owner, Quest Air owner) said go ahead and double up (four strands of Cortland Greenspot).

When the Rooney Links work so incredibly much better than all the other bullshit Rooney's seen out there Russell tells people to use a weak link that only works half as well. These weak links are effectively identical to the killer Tad-O-Link because in either configuration the triple strand protector of Bobby Fucking-Genius Bailey's tow mast breakaway is now THE system's weak link and what's on the glider is totally irrelevant.

Dr. Trisa Tilletti - 2012/06

It's not that it doesn't happen, but it is a rare occurrence. Russell Brown, a founder of Quest Air in Florida and a well-known Dragonfly tug pilot, is also a sailplane pilot, tug pilot, and A&P mechanic for a large commercial sailplane towing operation in Florida. He told us that, like us, he has never seen a sailplane weak link break, either. Russell owned the first 914-powered Dragonfly ever made--he helped us build the second one, which we still fly. He is the one who, many years ago, showed us the method for making a WT weak link and suggested we use polypropylene rather than Spectra for hang glider V-bridles.

Trisa reveals that Russell has taught them the secret of tying a loop of 130 pound Greenspot to hold to 520 pounds towline - twenty percent heavier than the Tad-O-Link that didn't break when it was supposed to and allowed Paul to go into a lockout and Russell to have his tail pulled around about the worst he has ever had it.

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Paul Tjaden - 2013/02/07 23:47:58 UTC

Zach was conscious immediately after the accident but died in route to the hospital.

Beyond these facts anything else would be pure speculation. I have personally had numerous weak link breaks on tow, both low and high, after hitting turbulence and have never felt in danger of a tumble. I have witnessed countless others have weak link breaks with no serious problems. We train aero tow pilots how to handle this situation and I am certain that Zach had also encountered this situation many times before and knew how to react properly. Apparently, Zach simply hit strong low level turbulence, probably a dust devil that could not be seen due to the lack of dust in Florida, the nose went too high and he tumbled at a very low altitude.

Strong dust devils in Florida definitely do exist even though they are rare. My wife had a near miss when she encountered a severe dusty a couple years ago and I almost lost a brand new $18,000 ATOS VX when it was torn from its tie down and thrown upside down.

I wish I could shed more light on this accident but I am afraid this is all we know and probably will know. Zach was a great guy with an incredible outlook and zest for life. He will be sorely missed.

While managing the inconvenience and enjoying the increased safety of a normal Rooney Link pop upon entering a thermal Zack Marzec is tragically struck by an invisible dust devil during his landing approach and fails to survive.

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Davis Straub - 2013/02/13 15:45:22 UTC

We have no agreement that a stronger weaklink would make it safer.

We have no agreement that a stronger weaklink would make it safer.

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks

Jim Rooney - 2013/03/04 19:31:36 UTC

The accepted standards and practices changed.
I still won't tow people with doubled up weaklinks. You don't get to "make shit up". I don't "make shit up" for that matter either.

We all play by the same rules, or we don't play.
Morningside decided that they were happy with 200lb weaklink. They changed their tug's link and they don't just pass the stuff out either. If you'd like to know more about it... go ask them.

We learn that we now have an additional accepted standard - 54 percent more dangerous that our previous proven system that works.

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Jim Rooney - 2013/03/05 21:40:02 UTC

You're afraid of breaking off with a high AOA? Good... tow with a WEAKER weaklink... you won't be able to achieve a high AOA. Problem solved.

The person with the keenest intellect and the comments to which we should give the most weight finally solves the problem for us by recommending safer weak links - Rooney Juniors.

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Davis Straub - 2013/07/04 13:47:57 UTC

Mark Knight and Jim Rooney put the loops through the wringer
(Francisco Grande, Casa Grande, Arizona)

Weak Link loops breaking test - April 2013
All knots tied with single fisherman's unless specified.

Breaking Lbs - Material

463 - Spectra Line used for Aero-towing (taken from used tow line, NOT NEW)

000 - (http://www.towmeup.com/weaklink.html)

330 - White with Black striker 300 lb.
308 - White with Red Striker 250 lb.
253 - White with Purple Striker 200lb 1knot
255 - White with Purple Striker 200lb 2knots

220 - Black Dacron fishing line 160 lb.
330 - Actual Tug Weaklink (Doubled Black) Black Dacron fishing line 160 lb.
286 - 205 Leach Line
154 - Courtland Greenspot 130 lb. (From Quest Air Florida)
099 - Cabellas Greenspot 130 lb.

187 - Double Loop Cabellas Greenspot
077 - Cabela's Greenspot No Lark's head
198 - Tandem Knot Cabela's Greenspot

Cabela's Green spot did not give consistent results) Not recommended

Mark Knight and Jim Keen-Intellect Rooney forego the hundreds of thousands of trail and error tows that were used to select 130 pound Greenspot that best meets our expectation of breaking as early as possible in lockout situations but being strong and reliable enough to avoid frequent breaks from turbulence and settle on bench testing - which may produce results with good internal validity but are often weak in regard to external validity.

Weak link material:
- safer than 130 pound Cortland Greenspot was rejected because it didn't give "consistent" results
- 1.23, 1.54, 1.58, 1.92, and 2.31 times as dangerous as 130 pound Cortland Greenspot was retained for consideration

Mark Knight - 2013/07/04

My calculations and test suggest the 200 lb. is right for me. I weigh 185 pounds, fly a T2 154 (75 lbs), and my harness fully loaded is 35 pounds. Total all up flying weight is 185 + 75+ 35 = 295 lbs. Times 1.4 = 413. I use Pro tow barrel release so divide by 2 = 206.5. I feel the White and purple is a good fit for me.

Mark Knight found weak link material 1.54 times as dangerous as 130 pound Cortland Greenspot to be a good fit for himself.

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing

Mark Dowsett - 2013/07/04 21:41:52 UTC

I left Quest with some of the towmeup.com material when I was there in April and they were going to do testing as well. I'm not sure what they are now using.

We learn that at some point within about a ten week period following Zack Marzec's invisible dust devil induced tumble Quest has acquired weak link material from Stuart Caruk - who only supplies 150, 200, 250, and 300.

- We know that they didn't have it before or at the time of Zack's freak accident Quest didn't have the material because....

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Jim Rooney - 2013/02/12 18:00:27 UTC

I just buried my friend and you want me to have a nice little discussion about pure speculation about his accident so that some dude that's got a pet project wants to push his theories?

Deltaman loves his mouth release.
BFD

I get tired as hell "refuting" all these mouth release and "strong link" arguments. Dig through the forums if you want that. I've been doing it for years but unfortunately the peddlers are religious in their beliefs so they find justification any way they can to "prove" their stuff. This is known as "Confirmation Bias"... seeking data to support your theory... it's back-asswards. Guess what? The shit doesn't work. If it did, we'd be using it everywhere. But it doesn't stand the test of reality.

AT isn't new. This stuff's been worked on and worked over for years and thousands upon thousands of tows. I love all these egomaniacs that jump up and decide that they're going to "fix" things, as if no one else has ever thought of this stuff?

But back to the root of my anger... speculation.
Much like confirmation bias, he's come here to shoehorn his pet little project into a discussion. Please take your snake oil and go elsewhere.

Tune him up?
Yeah, sorry... no.

These motherfuckers are flying 200 now and keeping it under heavy wraps.

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec

Paul Tjaden - 2013/02/07 23:47:58 UTC

Beyond these facts anything else would be pure speculation. I have personally had numerous weak link breaks on tow, both low and high, after hitting turbulence and have never felt in danger of a tumble. I have witnessed countless others have weak link breaks with no serious problems. We train aero tow pilots how to handle this situation and I am certain that Zach had also encountered this situation many times before and knew how to react properly. Apparently, Zach simply hit strong low level turbulence, probably a dust devil that could not be seen due to the lack of dust in Florida, the nose went too high and he tumbled at a very low altitude.

I wish I could shed more light on this accident but I am afraid this is all we know and probably will know.

I'm not all that thrilled when I look in a mirror but at least I'm not seeing anybody from Quest, Currituck, or Cloud 9 looking back.