Weak links

General discussion about the sport of hang gliding
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Hey Bill...

http://ozreport.com/forum/viewtopic.php?t=1143
Death at Tocumwal
Davis Straub - 2006/01/24 12:27:32 UTC

Bill Moyes argues that you should not have to move your hand from the base bar to release. That is because your natural inclination is to continue to hold onto the base bar in tough conditions and to try to fly the glider when you should be releasing.
Ya think that on Tuesday afternoon when Steven Tinoson got just about totaled in your backyard behind one of your ultralights specifically designed for towing hang gliders there was a problem with his natural inclination to continue to hold onto the base bar and try to fly the glider when he should have been releasing?

Dickhead.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Hey Davis...

http://ozreport.com/12.081
Weaklinks - the HGFA rules
Davis Straub - 2008/04/22 14:47:00 UTC

From section 3.4 of the 1999 Hang Gliding Federation of Australia Towing Manual:
Recommended breaking load of a weak link is 1g. - i.e. the combined weight of pilot, harness and glider (dependent on pilot weight - usually approximately 90 to 100 kg for solo operations; or approximately 175 kg for tandem operations).
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.
http://ozreport.com/13.238
Adam Parer on his tuck and tumble
Adam Parer - 2009/11/25

Due to the rough conditions weak links were breaking just about every other tow and the two tugs worked hard to eventually get everyone off the ground successfully.
http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Davis Straub - 2011/08/28 15:26:28 UTC

Then again, Russell Brown had us double up behind him after six breaks in a row at Zapata. We couldn't figure out why we had so many breaks so quickly. Maybe just coincidence.
http://www.hanggliding.org/viewtopic.php?t=31717
Weak link?
Davis Straub - 2014/08/20 19:48:26 UTC

Many of us are now using 200 lb test line from Cortland.
http://www.hanggliding.org/viewtopic.php?t=31747
Lockout
Davis Straub - 2014/09/01 15:22:41 UTC

I can tell you that I fly with a 200lb weaklink on one side of my 750lb pro tow bridle. I am happy with it.
Given that meet organizers have been proven beyond any faint shadow of a doubt to have been monumentally clueless regarding the determination of what appropriate and inappropriate weak links are is there some good reason that hang glider pilots should still be allowing these total douchebags to make equipment determinations for them?

P.S. It's Monday in Sydney.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/12.081
Weaklinks - the HGFA rules
Davis Straub - 2008/04/22 14:47:00 UTC

For many years a number of us (US pilots) have felt that #8 bricklayers nylon line was not an appropriate material to use for weaklinks as it is not as consistent in its breaking strength (as far as we are concerned) as the Greenspot line used in the US. 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://www.hanggliding.org/viewtopic.php?t=31717
Weak link?
Davis Straub - 2014/08/20 19:48:26 UTC

Many of us are now using 200 lb test line from Cortland.
Good thing you're still using Cortland. It's got those really excellent tolerances that are so critical to weak link performance. When you've determined that 130 is the perfect one-size-fits-all weak link it breaks very predictably when it's supposed to. Same thing when many of us are flying and happy with 200.

I'll bet that Steven Tinoson idiot was flying with some of that #8 bricklayers line. That sure didn't break when it was supposed to. Shoulda listened to Bobby. He's a fucking genius when it comes to this shit. Stupid Aussie twats.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Hey Davis...

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.

I'm thinking about doing a bit more testing as there seemed to be some disagreement around here about what the average breaking strength of a loop of Greenspot (or orange) weaklink was.
But what you - and many of you - are actually DOING...

http://www.hanggliding.org/viewtopic.php?t=31717
Weak link?
Davis Straub - 2014/08/20 19:48:26 UTC

Many of us are now using 200 lb test line from Cortland.
http://www.hanggliding.org/viewtopic.php?t=31747
Lockout
Davis Straub - 2014/09/01 15:22:41 UTC

I can tell you that I fly with a 200lb weaklink on one side of my 750lb pro tow bridle. I am happy with it.
...is the precise opposite of what you're SAYING. You're SAYING you're happy to have a relatively WEAK weak link when, in fact, you're happy using a relatively STRONG weak link which will blow the Dragonfly's tow mast breakaway protector - which Quest has been perfecting for twenty years - and leave you with 250 feet of Spectra draped over your basetube.

Did something happen after all that discussion to influence your "thinking" on the issue? Was there some other discussion that I missed?

It's really confusing to all us muppets...

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/forum/viewtopic.php?t=30971
Zach Marzec
Jim Rooney - 2013/02/15 06:48:18 UTC

Davis has been at an around all this plenty long enough to understand what's what and who's who.
...when we can't understand why the best of the best...

Image
http://ozreport.com/pub/images/fingerlakesaccident2.jpg
http://ozreport.com/pub/images/fingerlakesaccident3.jpg
Image

...are doing what they're doing.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

http://groups.yahoo.com/group/skysailingtowing/message/7230
Towing question
Martin Henry - 2009/06/26 06:06:59 UTC

PS... you got to be careful mentioning weak link strengths around the forum, it can spark a civil war ;-)
Civil War is OVER - motherfucker. Zack Marzec - 2013/02/02 - was Pickett's Charge and we're in Appomattox / mop up mode now. Mention REAL weak link strengths around a forum now and the pro slavery people go DEAD FUCKIN' SILENT. Only took us a bit over eight times as long as the 1861-1865 edition. Oh well, much smaller scale, scope of casualties a lot more limited - although a few of them were just as severe.

Don't expect us to be as magnanimous in victory as Lincoln was, though. There was NOTHING on the other side in the way of courage, chivalry, decency to merit it.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Hey Davis...

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.

I'm thinking about doing a bit more testing as there seemed to be some disagreement around here about what the average breaking strength of a loop of Greenspot (or orange) weaklink was.
http://www.hanggliding.org/viewtopic.php?t=31717
Weak link?
Davis Straub - 2014/08/20 19:48:26 UTC

Many of us are now using 200 lb test line from Cortland.
http://www.hanggliding.org/viewtopic.php?t=31747
Lockout
Davis Straub - 2014/09/01 15:22:41 UTC

I can tell you that I fly with a 200lb weaklink on one side of my 750lb pro tow bridle. I am happy with it.
You - and many of you - are now using 200.

And you're obviously all HAPPY with it. It's not like you've got some brain damaged dickhead like Jim Keen-Intellect Rooney or Davis Dead-On Straub FORCING you to use it - the way things have been since the beginning of time with 130.

So maybe you can explain to us muppets WHY you're HAPPY with it.

You're obviously not using it to protect from overload.
- You:
-- have stated that that's a crappy idea.
-- are using those really slick bent pin releases that you can close over a thick rope without using a weak link.
- There's not a glider on the planet that's anywhere near breaking a sweat at four hundred pounds towline.

So about the only other thing I can think of is exactly what you've stated. You're happy with it's effectiveness as a release. An emergency release, right?

So how many times did you have your life/ass/bacon saved by your two hundred pound emergency release before you decided you were happy with it? How 'bout the many others of you? Anybody have any close enough calls to think a bit about dropping back down to 180?

What was wrong with the 130? Wasn't that giving you much wider safety margins? You'd never had a serious problem with it, just an inconvenience now and then. And it was a proven system that worked with an absolutely astronomical track record.

But maybe all you goddam motherfuckers HAPPY with them for the exact same reason sailplane people are happy with THEIRS...
Dr. Trisa Tilletti - 2012/06

You and I have flown sailplanes for almost as long as we have flown hang gliders. We own two sailplanes and have two airplanes that we use for towing full-size sailplanes. In all the time that we have flown and towed sailplanes, we have not experienced or even seen a sailplane weak link break.

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.
THEY NEVER BREAK.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Hey Davis...

http://www.hanggliding.org/viewtopic.php?t=31811
Weak link material
Davis Straub - 2014/09/12 01:00:16 UTC

Wills Wing T2C 144.
200-210 lb. hook in weight.
http://www.hanggliding.org/viewtopic.php?t=31747
Lockout
Davis Straub - 2014/09/01 15:22:41 UTC

I can tell you that I fly with a 200lb weaklink on one side of my 750lb pro tow bridle. I am happy with it.
I fly maxed out on my HPAT 158 at 320 and I'm not good enough to fly pro toad like you do - and Zack Marzec used to. So using a two point bridle, what you would call a three point (probably 'cause of your fucked up wiring from all those concussions), there's more load on my weak link - as I had to explain to your stupid incompetent ass...

http://ozreport.com/forum/viewtopic.php?t=15716
Weak Links
Tad Eareckson - 2009/04/22 14:38:53 UTC

It's why the cables droop instead of being stretched to horizontal.

Image

Yeah, I'm totally cool with Greenspot for pro-tow - for anyone who's gonna be dead from anorexia in a couple of days anyway.
Davis Straub - 2009/04/22 15:00:07 UTC

What are you talking about?
And what does the Golden Gate bridge have to do with anything?
...five and a half years ago.

I too would like to fly at one and a half Gs 'cause I think that would give me happiness equivalent to what you enjoy. But if I use the same weak link many of us are now happy with I don't quite make it up to 1.1 Gs. I need to go up to about 275. Am I allowed to do that or...

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks
Jim Rooney - 2013/03/03 19:37:19 UTC

See, most people are happy with how we do things. This isn't an issue for them. They just come out and fly. Thing's aren't perfect, but that's life... and life ain't perfect. You do what you can with what you've got and you move on.

But then there's a crowd that "knows better". To them, we're all morons that can't see "the truth".
(Holy god, the names I've been called.)

I have little time for these people.
...do I STILL hafta be happy with how "WE" do things - the way I did when everyone was all orgasmic over...

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Davis Straub - 2011/08/28 15:26:28 UTC

Then again, Russell Brown had us double up behind him after six breaks in a row at Zapata. We couldn't figure out why we had so many breaks so quickly. Maybe just coincidence.
...130?

What's the lightest of the many of us who've recently decided they're happier with the 200 than they were with the 130? Are two hundred pound pro toad little girl gliders permitted to be happy with the 200 - maxed out at the top of the FAA legal range? Should weak links vary with glider capacity or flying weight - the way it's always specified in the FAA regulations and USHGA SOPs? Or are we now all headed for 200 Pound Greenspot One-Size-Fits-All Paradise to replace Version 1.0?
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

http://www.questairforce.com/aero.html
Quest Air Aerotow FAQ
Weak Link

The strength of the weak link is crucial to a safe tow. It should be weak enough so that it will break before the pressure of the towline reaches a level that compromises the handling of the glider but strong enough so that it doesn't break every time you fly into a bit of rough air. A good rule of thumb for the optimum strength is one G, or in other words, equal to the total wing load of the glider. 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.

IMPORTANT - It should never be assumed that the weak link will break in a lockout.
ALWAYS RELEASE THE TOWLINE before there is a problem.
http://ozreport.com/5.126
Flytec Dragonfly
USAFlytec - 2001/07/14

Steve Kroop - Russell Brown - Bob Lane - Jim Prahl - Campbell Bowen

The tail section of the Dragonfly is designed so that it can accept in-line as well as lateral loads. Furthermore the mast extension, which is part of the tow system, is designed to break away in the event of excessive in-line or lateral loads. The force required to cause a breakaway is roughly equivalent to the force required to break the double weaklink used on the tail bridle. More simply put, the mast would break away long before any structural damage to the aircraft would occur.
http://ozreport.com/forum/viewtopic.php?t=865
Tandem pilot and passenger death
Martin Henry - 2005/09/09 17:05:50 UTC

What is known, the event (2002/08/17 - William Woloshyniuk/Victor Cox) occurred at or near the departure from the tug. The departure from tow was reported (by the tug operator) to be a violent separation. The tug (Moyes) suffered a failed vertical pylon on the upper portion of the tug end V bridal, just prior to the tug end weak link failure.
FAR 91.309 - 2004/09
91.309(a)(3) The towline used has a breaking strength not less than 80 percent of the maximum certificated operating weight of the glider or unpowered ultralight vehicle and not more than twice this operating weight. However, the towline used may have a breaking strength more than twice the maximum certificated operating weight of the glider or unpowered ultralight vehicle if--

(i) A safety link is installed at the point of attachment of the towline to the glider or unpowered ultralight vehicle with a breaking strength not less than 80 percent of the maximum certificated operating weight of the glider or unpowered ultralight vehicle and not greater than twice this operating weight.

(ii) A safety link is installed at the point of attachment of the towline to the towing aircraft with a breaking strength greater, but not more than 25 percent greater, than that of the safety link of the towed glider or unpowered ultralight vehicle end of the towline and not greater than twice the maximum certificated operating weight of the glider or unpowered ultralight vehicle.
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3600
Weak link question
Jim Rooney - 2008/11/24 18:54:27 UTC

I'm confused. I never said the tug's ass was endangered. That's why we use 3strand at the tug's end. Using 4 strand can rip things off (it's happened). When forces are achieved that do break a 3 strand, your tail gets yanked around very hard, which does have implications as to the flight characteristics and flightpath. AKA, I have no desire to allow you to have the ability to have that effect on me when I tow you... esp near the ground.
Jim Rooney - 2008/11/24 23:38:01 UTC

It's not "uncharted territory"... you're just not aware of what's been done. Just as you weren't aware of the reason for 3 strand links on the tug.
Yeah Jim. The reason we weren't aware of the three strand on the tug and the "reason" you swapped out the four is 'cause we're all a bunch of hopelessly clueless muppets - not, of course, 'cause you off the scale stupid criminally negligent serial killing pigfuckers dumbed things down to protect the cheap crap on the back of your shitty tug, rather than beef it up to keep more gliders from being killed, and didn't bother telling us what you were doing.

And that bullshit from those total fucking morons at Quest was still up while you were busy impressing us with your keen intellect and knowledge of the issues when it comes to most things in general and hang glider aerotowing in particular.

Fuck you, Mitch. And I've got some bad news for ya...

http://ozreport.com/forum/viewtopic.php?t=22660
What can be learned from this "scooter" towing accident?
Mitch Shipley - 2011/01/31 15:22:59 UTC

Enjoy your posts, as always, and find your comments solid, based on hundreds of hours / tows of experience and backed up by a keen intellect/knowledge of the issues when it comes to most things in general and hang gliding AT/Towing in particular. Wanted to go on record in case anyone reading wanted to know one persons comments they should give weight to.
Nobody's buying YOUR moronic bullshit any more either. Really appreciate you GOING ON THE RECORD with that.
miguel
Posts: 289
Joined: 2011/05/27 16:21:08 UTC

Re: Weak links

Post by miguel »

How does one do this?
"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."

TIA
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Any way you like. When people ACTUALLY TEST weak links...

http://ozreport.com/forum/viewtopic.php?t=32824
Weaklink testing
Mark Knight - 2013/07/04

The knots do not matter so much for just one tow to how they break or the breaking strengths. A double fisherman's knot or a Tandem multi-wrap knot will not give better strength but wears less on the weak link and therefore last longer.
...they all find that there's not enough difference in breaking strengths to be worth mentioning between weak links with the knot totally hidden and totally exposed. 260 pound weak links actually blow at 130 pounds - just like 130 pound weak links.

Nevertheless... Irrespective of breaking strength, THIS:

http://www.flickr.com/photos/aerotowrelease/8313955230/
Image
Image
http://www.flickr.com/photos/aerotowrelease/8312907083/

is the only proper, non stupid, aesthetically pleasing configuration for installing a weak link on a bridle. (Ignore the sailmaker's thimble.)

Form the loop with a Fisherman's Knot - totally bulletproof.

Install the loop on the bridle (bridal - for aerotow professionals) using a Double Lark's Head with the knot position so that it's hidden from the main tension in the link and excluded altogether from the equation. Stays put very nicely during prep. Stays put REALLY nicely during prep after it's been subjected to tow tension (pressure - for aerotow professionals).

Be VERY conservative on material length. It's AMAZING how things elongate when fully seated. Proper way to do it is guess the length on a test loop, install it, fully load it, and see how many millimeters you need to knock off to just adequately accommodate whatever release you're using...

http://www.flickr.com/photos/aerotowrelease/8312900703/
Image

...and no more. (Pretend the 130 pound Greenspot is something - ANYTHING - else.)

http://ozreport.com/forum/viewtopic.php?t=24534
It's a wrap
ImageImageImageImage

Total fuckin' morons. They were total fuckin' morons even BEFORE Lauren moved down there and contributed her IQ to the average.
Post Reply