Weak links

[Tad Eareckson]

http://www.chgpa.org/forums/viewtopic.php?f=2&t=4788
Highland March20?

Ward Odenwald - 2011/03/22 02:15:06 UTC

To echo what others have already posted - Highland had another great season opener on Sunday! Early morning forecasts indicated light easterly winds during the day coupled with a decent lapse rate/thermal index and by noon the soaring forecasters had nailed it.

I flew twice.

My first tow took me to ~20 feet above the deck before my weak link snapped resulting in a fifty yard high-adrenalin flight...

High-adrenalin? For in increase in the safety of the towing operation? How come your adrenalin level didn't immediately drop to checkers mode? Or are you trying to make more of this crappy argument that being on tow is somehow safer than being off tow?

...(in the future, I'll start the new season with new links).

Yeah, who ever heard of a brand new Rooney Link...

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...blowing for no reason on its first flight? Always make sure you have one in top condition so's it will work in accordance with your expectations.

The second flight lasted 1.5 hours with most of that time spent above 2500 feet MSL and climbs up to the inversion layer ceiling which was at ~4300 (judging from my altimeter and photos). As John posted, some of the thermals were well organized, giving us climb rates during consecutive 360s of over 500 ft/min. It's a great feeling when you're circling in solid lift and you can enjoy the view.

Can't really compare to the feeling you get when your Rooney Link increases the safety of the towing operation though, can it?

[Tad Eareckson]

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.

Yeah, just like THIS:

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


one. Instant hands free release.

That that is exactly what has happened to me in a number of situations...

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

...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.

Well that's just great, Davis. But maybe you can cite the relevant references in all that discussion so's the rest of us down here in Muppetland can reach the same conclusions.

I'm a little confused though. I myself decided to go in the precise opposite direction after reading THIS:

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

Brad Gryder - 2013/02/21 23:25:31 UTC

There's also a way to swing your body way outside the control frame so it stays up there while you reach out with one hand and release. Come on - do some pushups this winter. See if you can advance up to some one-arm pushups.

I've worked my way up to one-arm pushups and I'm now thoroughly convinced that, unlike you and the other assholes running Quest, I can use the...

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

Davis Straub - 2011/07/30 19:51:54 UTC

I'm very happy with the way Quest Air (Bobby Bailey designed) does it now.

...bent pin crap they sell in a lockout by swinging my body way outside the control frame so it stays up there while I reach out with one hand and release. So why would ANYONE not wanna go that route and triple their Davis Link strengths to reduce the inconvenience?

Or did you miss that part of the discussion? I've just been assuming you were totally on board with it as you made no comment indicating anything to the contrary.

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.

You've also tried to launch unhooked on...

http://ozreport.com/forum/viewtopic.php?t=18695
How could this accident happen?

Davis Straub - 2010/01/28 06:10:17 UTC

I have tried to launch unhooked on aerotow and scooter tow.

...aero and scooter 'cause you're too much of a total douchebag to do hook-in checks so, obviously, those issues can be no more than inconveniences for anyone else either.

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.

Just revise the rules such that competitors can use whatever the fuck weak links they feel like as long as they can do four one-arm pushups on each arm. If they can't just put them up on 130 pound Greenspot and, if they fail to maintain the correct tow position (centered, with the wheels of the tug on the horizon), it will break before they can get into too much trouble - just like you're saying it will.

How come with all this experience we're gaining and productive discussions we're having and the people with the keenest intellects constantly working to perfect aerotowing everything looks and runs exactly the same way it did over two decades ago?

[Tad Eareckson]

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

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

What material should be used for weaklinks? (Hughenden airport, QLD, Australia)

From section 3.4 of the 1999 HGFA Towing Manual:

Recommended breaking load of a weak link is 1g. - i.e. the combined weight of pilot, harness and glider (dependant on pilot weight - usually approximately 90 to 100 kg for solo operations; or approximately. 175 kg for tandem operations).

Each pilot should have his/her own weak link of appropriate strength.

It is recommended that a new weak link is used for every launch; or a fabric sheath is used to cover the weak link to protect it as it is dragged along the ground.

Testing weak links tied from "No 8" builders string line has shown that the type of knot used does not greatly affect the breaking strain of the weak link.



I have chosen only the relevant part of the graphic in the manual. Notice that it uses No. 8 bricklayers twine as the weaklink material. Here is the requirement from the 2007 Worlds local rules (which I wrote) for weaklinks:

Appropriate aerotow bridles

Competitors must use appropriate aerotow bridles as determined by the Meet Director and Safety Director and their designated officials. Bridles must include secondary releases (as determined by the Safety Director). Bridles must be able to be connected to the tow line within two seconds. The only appropriate bridles can be found here:
http://www.ozreport.com/9.039#0

and:
http://ozreport.com/9.041#2



Pilots who have not already had their bridles inspected during the practice days must bring their bridles to the mandatory pilot safety briefing and have them reviewed. Pilots with inappropriate bridles may purchase appropriate bridles from the meet organizer.

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 http://www.cortlandline.com/catalog/braid.html and should be placed at one end of a shoulder bridle. The tow forces on the weaklink will be roughly divided in half by this placement. Pilots will be shown how to tie the weaklink so that it more likely breaks at its rating breaking strength.

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.

If the weaklink is at one end of the bridle then there is little to no reason to replace the weaklink after each flight. The weaklink should be replaced if it shows any signs of wear as its strength may be reduced. The weaklink is constructed using "fisherman's knots."

A single loop of weaklink is used at the end of the V-bridle or the end of the pro tow bridle.

Pilots at the 2007 Worlds were not actually required to use the bridles pictures above unless their bridle couldn't be hooked up quickly to the carabineer at the end of the tow rope. They could have a weaklink (four strands) that connected their bridle to the carabineer. They just had to have the loops of the weaklink available to be hooked to by the ground crew. This would obviously require a carabineer at the end of the tow rope, and would leave the weaklink attached to the carabineer after the pilot releases, requiring that it be taken off by the ground crew before hooking up to the next pilot. Of course, a locking carabineer could be used.

It was required that pilots be able to be connected to the tow line quickly both in order to be fair to all pilots and get them in the air in time to compete with each other, as well as to promote safety. It is safer to have a simple uniform release/bridle system that the ground crew is familiar with and can determine if there is a problem. The simpler and more uniform the safer, system wide.

Getting pilots into the air quickly is also safer as it reduces the stress that pilots feel on the ground and keeps them focused on their job which is to launch safely and without hassling the ground crew or themselves. When we look at safety we have to look at the whole system, not just one component of that system. One pilot may feel that one component is unsafe from his point of view and desire a different approach, but accommodating one pilot can reduce the overall safety of the system.

I look forward to any response from the HGFA or other interested persons. Again, I have a direct personal and minor financial interest in the issues raised by this discussion, but no financial interest when it comes to weaklink material.

Discuss Weaklinks at the Oz Report forum

[Tad Eareckson]

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

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

What material should be used for weaklinks?

Yeah Davis... We don't need to discuss what the purpose of the weak link is, what it can and can't be expected to do, issues involved in varying G ratings, FAA regulations covering hang glider aerotowing weak links... so let's just go ahead and talk about the material we should use.

Recommended breaking load of a weak link is 1g. - i.e. the combined weight of pilot, harness and glider (dependant on pilot weight - usually approximately 90 to 100 kg for solo operations; or approximately. 175 kg for tandem operations).

- Who recommended that breaking strength?

- What are his qualifications?

- Why is that breaking strength recommended? What are the issues going up and down from that recommendation?

- Is there any field data we can review which clearly supports / serves as a foundation for this recommendation?

- Do competent pilots just follow recommendations because some anonymous asshole at HGFA who has difficulty spelling "DEPENDENT" states that it's RECOMMENDED or do they make they're own decisions based upon their understandings of issues?

- USHGA recommends one and a half to two times what HGFA recommends. Is this discrepancy somehow related to the Coriolis Effect?

- Why are you fucking douchebags telling us what flying weights "USUALLY APPROXIMATELY" are?

-- If you're RECOMMENDING one G shouldn't we know EXACTLY what they are?

-- Should a 160 KG glider use a 90 to 100 KG weak link 'cause you've stated that's USUALLY APPROXIMATELY the weight of a solo glider?

-- A Falcon 3 Tandem can fly anywhere between 116 and 259 but 175 is close enough. So 0.66 to 1.48 Gs is close enough to the recommendation. Or do you know of tandem operations that swap out weak links depending upon what's under the glider?

- The FAA says ABSOLUTELY NOTHING about:
-- flying weight
-- recommendations
-- usually approximately bullshit

It MANDATES a range between eighty and two hundred percent of max certified operating weight. How come you say ABSOLUTELY NOTHING about max certified operating weight?

- ALL sailplane manufacturers specify around 1.4 times max certified operating weight for AT weak links. Why that discrepancy?

- Why are there ZERO hang glider manufacturers specifying or recommending ANYTHING in the way of weak link rating?

- The main - virtually only - manufacturer of sailplane, ultralight, hang glider, paraglider weak links states:

Tost Flugzeuggerätebau

Weak links protect your aircraft against overloading.

EVERYBODY understands that and understands the specified ratings. Why do you say NOTHING about the PURPOSE of the weak link and RECOMMEND a rating that has NOTHING to do with overloading ANYTHING?

- Are you RECOMMENDING one G as a lockout protector or mitigator? Do you have ANY data or evidence to indicate that one G is of ANY significant value in protecting ANYONE - at either end of the string - against...

07-1522

11-1814

12-1915


...potentially and actually lethal lockouts?

- Your recommendation of one G is considerably lower than:
-- the middle of the FAA's legal range
-- sailplane manufacturer specifications
-- USHGA recommendations

Sailplanes use the weak links they do because stuff heavier starts overloading the release mounts and lighter stuff is...

http://zweefvliegopleiding.nl/index.php/thermiek


...dangerous.

USHGA recommends 1.5 Gs because:

- none of the bent pin shit...





...they use as releases can:
-- handle more than half that load
-- be actuated in lockouts so their only hope of survival is having the weak link break when they're plenty high

- light weak link breaks are...

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


...inconvenient - in much the same way that light sailplane weak link breaks are dangerous

So are you still maintaining the same recommendation?

[Tad Eareckson]

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

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

Each pilot should have his/her own weak link of appropriate strength.

Really?

- "Appropriate strength" being one G because that's just been RECOMMENDED by some douchebag - who can't spell "dependent" or run a check before publishing it in a critical document - with absolutely no explanation of why that's RECOMMENDED or reference to the purpose of the weak link.

- So how come some total douchebag - who can't spell "Trolling" (which is really ironic given the kind of individual he is) - using your SOPs as a model, immediately below states:

Weaklinks will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line

- I was under the impression that...

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

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

We all play by the same rules, or we don't play.
The law of the land at comps was 130lb greenspot or you don't tow. Seriously. It was announced before the comp that this would be the policy. Some guys went and made their case to the safety committee and were shut down. So yeah, sorry... suck it up.

...we all play by the same rules or we don't play - the same rules meaning heavier gliders fly at lighter weak link ratings and lighter gliders fly at heavier weak link ratings. Can you explain to me how we got to these positions using your document as a foundation?

It is recommended that a new weak link is used for every launch; or a fabric sheath is used to cover the weak link to protect it as it is dragged along the ground.

Why?

- Doesn't an unprotected weak link dragged along the ground...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3600
Weak link question

Jim Rooney - 2008/11/25 19:21:57

Brian,
While I appreciate your quest for the perfect weaklink, didn't we cover this already? (Again?)
Are we to go down the road of debating the quality standards of greenspot again?
Ok, for review, it doesn't matter.
Why?
Because you have nothing else.
Do I have to review why we don't tow handmade gliders?

Listen we're all perfectly aware that greenspot is not laser calibrated to 130lbs. It's bloody fishing line. Get over it. Are you flying below your perfect numbers as a heavy guy. Yes. Yes you are. Get over it.
Why?
Because it's all you've got.

Why lower numbers? Because your choice is lower or higher... and higher is more dangerous than lower.

...just get safer?

- Here in the States we've found over the course of several decades of experience and hundreds of thousands of tows conducted by numerous aerotow operators across the county single loops of 130 pound Greenspot to be ideal for establishing long track records and working. They put most gliders well under the one G you're recommending. Shouldn't you be dragging your weak links along the ground a bit to bring them more in line with our proven system?

- Weak links that break before their supposed to are mere inconveniences at worst, nobody's ever been so much as scratched because of a break... Why are wasting valuable document space to protect us from inconveniences? You might as well recommend taking a pee before suiting up in our harnesses (only when connected to our gliders...

11-A12819
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...of course).

Testing weak links tied from "No 8" builders string line has shown that the type of knot used does not greatly affect the breaking strain of the weak link.

Sorry, but I couldn't disagree more!

If you read Dr. Trisa Tilletti's fourteen page article on weak links in the issue of Hang Gliding magazine - the most trusted source of information on hang gliding technology on the planet - that came out almost exactly two years ago you will find that the knot you use has a HUGE effect on the strength. With a less than perfect knot the weak link will break inconsistently - sometimes when you want it to, other times when you don't. With the perfect knot the weak link will break consistently at whatever strength you feel like saying it does and it will meet your expectation of breaking as early as possible in lockout situations but being strong and reliable enough to avoid frequent breaks from turbulence.

TESTING weak links on the ground is a total waste of time because the results can have no external validity. You're much better off just making an assumption about the strength of, if that proves too difficult, just pulling a number out of your ass and telling large numbers of people what it is. That's how Quest handles the issue and they've been perfecting aerotowing for twenty years.

[Tad Eareckson]

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

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

I have chosen only the relevant part of the graphic in the manual.

Great! You chose well!



Pretty obvious that a lot of people put a lot of time, work, and thought into that one.

Notice that it uses No. 8 bricklayers twine as the weaklink material.

That's totally fucking insane. Over here 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.

The number of people the Aussies have killed with their No. 8 bricklayers twine is absolutely staggering. When will people ever learn?

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

THANK GOD!!! Competition regulations from somebody who's been at an around all this plenty long enough...

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.

...to understand what's what and...


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


...who's who! It must be wonderful to be Davis and just write whatever crap you want and be in a position - along with your fellow pigfuckers - to shove it down everyone's throats.

[Tad Eareckson]

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

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

Appropriate aerotow bridles

Competitors must use appropriate aerotow bridles as determined by the Meet Director and Safety Director and their designated officials.

Hey Davis...

Any chance the next time these assholes permit someone to write competition rules they could look for candidates not so brain damaged that they're completely unable to differentiate between releases, bridles, weak links, release assemblies?

Bridles must include secondary releases (as determined by the Safety Director).

- BRIDLES CAN'T include secondary releases. A BRIDLE is a PIECE OF ROPE that has a WEAK LINK on any end at which a RELEASE is engaged and feeds out through a TOW RING on the end of a TOWLINE when (if) a RELEASE or WEAK LINK is blown.

- Why do you need a secondary release? Is there some problem with the primary...

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.

...release that should but can't be addressed? Aw, what the hell... If the first release doesn't work you should be able to pull an identical release on the other side and get better results - assuming you haven't already slammed in and broken your fuckin' neck.

Bridles must be able to be connected to the tow line within two seconds.

Well DUH! Why would ANYONE use a "BRIDLE" he couldn't connect to the towline...


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


...within two seconds?

DISconnecting from the towline... Who the fuck cares? You have the rest of the tow...

01-001

04-200

07-300

10-307

15-413


...to worry about that. Sometimes you have...

http://forum.hanggliding.org/download/file.php?id=11565


...the rest of your life. Besides... You have a weak link which, if you fail to maintain the correct tow position (centered, with the wheels of the tug on the horizon), will break before you can get into too much trouble.

The only appropriate bridles can be found here:
http://www.ozreport.com/9.039#0

and:
http://ozreport.com/9.041#2

- What criteria did you use to determine that the cheap bent pin crap you and your brain damaged pigfucker buddies pollute the market with were the only "appropriate" "bridles"?

- Obviously you're making this rule, not to advertise, promote, sell the cheap bent pin crap you and your brain damaged pigfucker buddies sell, but because you're deeply concerned with the safety of the competitors and you've had some really ugly experiences with inappropriate bridles. So...

-- How come there are any of these lethal pieces of crap still in circulation? Surely advisories have gone out, been published in the magazine, announced at the Jack and Davis Shows, and responsible pilots and operations have made sure they've all been grounded.

-- Where are these advisories? The only one I can recall was the Moyes/Quallaby spinnaker shackle release which snagged the focal point of the safe towing system and killed Robin Strid. And you fixed that problem by banning it (for a short while) from the 2005 Worlds at Hay. And now it's fine and everyone and his dog is using it with outstanding results.

-- How 'bout publishing some photos of inappropriate bridles with descriptions of the lethal flaws and defects so's we can sell them on eBay, replace them with bent pin barrel releases with long track records and blacklist and boycott the callous motherfuckers who are putting them on the market? How 'bout the one Steve Elliot was using - for starters? Or did you just show us some photos of that one?

- What was it that got all two point systems eliminated from any chance of consideration? The fact that the users...

01-1225
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03-1304
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...would have all the pro toads....

03-02421
http://farm8.staticflickr.com/7200/14097626583_03972773c6_o.png


...at grotesquely unfair survivability disadvantages?

Pilots who have not already had their bridles inspected during the practice days must bring their bridles to the mandatory pilot safety briefing and have them reviewed.

- Why don't you just publish the specs and performance standards your ace bridle inspectors are looking for so's everyone can just breeze through the process on comp day? Or would that decrease the profitability of the ace bridle inspectors condemning equipment and forcing competitors to buy the crap they're selling?

- Why will any mention of wheels and weak links proportional to glider weights and capacities be conspicuously absent from the discussion at the safety briefing?

Pilots with inappropriate bridles may purchase appropriate bridles...

Just like the one Zack Marzec was using at Quest...

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


...on 2013/02/02 or Ben Dunn was using at Luling...



...a bit over four months later.

...from the meet organizer.

Why don't you have Moyes people running the show and checking competitors for inappropriate gliders? Then when somebody shows up from halfway around the world with some piece of crap from Wills Wing he'll be able to purchase an appropriate glider from the meet organizers.

[Tad Eareckson]

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

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

Weaklinks

Pilots must use weaklinks provided by the meet organizers and in a manner approved by the meet organizers.

Well great! That way when a pilot's mandated sacred piece of piece of fishing line breaks at the worst possible time, when the glider is climbing hard in a near stall situation, the meet organizers won't be hurt and will be able to continue providing weak links and making sure they're used in a manner they approve.

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.

Well yeah! Inappropriate weak links could be REALLY DANGEROUS. They might not break when they're supposed to or break when they're NOT supposed to. And extra inappropriate weak link would probably do both on the same flight! Chances are that Jim Keen-Intellect Rooney would have to sacrifice a lot of his valuable time visiting such an individual in the hospital.

And a tug towing a solo glider with an inappropriate weak link on it is capable of STALLING! (A stall is what results for the glider when the weak link breaks. But those are GOOD things for the glider because if the weak link hadn't dumped the glider into a stall it would've locked out within the next five seconds. And there's no way to abort a tow using an appropriate bridle. And the tug pilot's ability to fix whatever's going on back there by giving you the rope is totally neutralized when an inappropriate weak link is being used.)

(It's OK for tandems to use inappropriate weak links. While they ARE stronger than the tug's appropriate weak link they WON'T override it - and thus the tug will be stall-proof. (Just make sure both carabiners are properly engaged because if somebody falls out the glider becomes a solo with an inappropriate weak link and all hell will break loose.))

If somebody got to the front of the line with an inappropriate weak link at a meet *I* was organizing I wouldn't require him to go to the end of the launch line to change the weak link - I'd splash him a faceful of acid. Then see just how many pilots would try to endanger themselves and their tug pilots with inappropriate weak links.

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.

Can't get any gliders airborne in light morning conditions using appropriate weak links. Everybody double them and we'll see what happens. Light morning conditions today only!

Weaklinks will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line http://www.cortlandline.com/catalog/braid.html and should be placed at one end of a shoulder bridle.

- Well yeah that's PERFECTLY consistent with:

Recommended breaking load of a weak link is 1g. - i.e. the combined weight of pilot, harness and glider (dependant on pilot weight - usually approximately 90 to 100 kg for solo operations; or approximately. 175 kg for tandem operations).

Each pilot should have his/her own weak link of appropriate strength.

Like a fucking game of telephone in a fucking lunatic asylum.

- Since APPROPRIATE bridles:





all have cheap shoddy bridles ten times longer than the bridles of INAPPROPRIATE bridles:

http://www.flickr.com/photos/aerotowrelease/8306152861/

http://www.flickr.com/photos/aerotowrelease/8306164803/

http://www.flickr.com/photos/aerotowrelease/8313526097/


...and are known to wrap at the tow ring...

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

Jim Rooney - 2009/11/02 18:58:13 UTC

Oh it happens.
I have, all the guys I work with have.
(Our average is 1 in 1,000 tows)

Oh yeah... an other fun fact for ya... ya know when it's far more likely to happen? During a lockout. When we're doing lockout training, the odds go from 1 in 1,000 to over 50/50.

over half the time in emergency simulations, could you please explain to me what your "thinking" is in not putting weak links on BOTH ends of the appropriate bridle's bridle? Is the problem that...

http://www.hanggliding.org/viewtopic.php?t=27393
Pro towing: 1 barrel release + weak link or 2 barrel release

Juan Saa - 2012/10/18 01:19:49 UTC
Boca Raton

The normal braking force in pounds for a weak link is around 180, at least that is the regular weak link line used at most aerotow operations. By adding a second weak link to your bridal you are cutting the load on each link by half, meaning that the weak link will not break at the intended 180 pounds but it will need about 360.
If that is what you use and is what your instructor approved then I have no business on interfering, i dont know if you are using the same weak link material but there shoul be only ONE weak link on a tow bridle for it to be effective in breaking before higher loads are put into you and the glider should the glider gets to an attitude or off track so much that the safety fuse of the link is needed to break you free from the tug.

I made the same mistake on putting two weak links thinking that I was adding protection to my setup and I was corrected by two instructors on separate occacions at Quest Air and at the Florida RIdge.

...that will double the towline tension required to blow tow like the people who've been perfecting aerotowing for twenty years say it will?

No, wait. If you put weak links on BOTH ends of the bridle that wouldn't be in a manner approved by the meet organizers. Sorry, wasn't really paying attention.

- Any chance you could tell us what:

-- the PURPOSE -- sorry...

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

Jim Rooney - 2011/08/28 10:15:12 UTC

Oh, in case it's not obvious (which it doesn't seem to be), once someone starts telling me what the "sole" purpose of a weaklink is, I tune them out as they have no clue what they're talking about.

Weaklinks are there to improve the safety of the towing operation, as I've stated before.

Any time someone starts in on this "sole purpose" bullshit, it's cuz they're arguing for stronger weaklinks cuz they're breaking them and are irritated by the inconvenience. I've heard it a million times and it's a load of shit. After they've formed their opinion, then they go in search of arguments that support their opinion.

...PURPOSES of this weak link are supposed to be?

-- the breaking strength of a single loop of Cortland 130 pound Greenspot braided Dacron Tolling line is and how you determined it - given that...

Dr. Trisa Tilletti - 2012/06

We could get into details of lab testing weak links and bridles, but this article is already getting long. That would be a good topic for an article in the future. Besides, with our backgrounds in formal research, you and I both know that lab tests may produce results with good internal validity, but are often weak in regard to external validity--meaning lab conditions cannot completely include all the factors and variability that exists in the big, real world.

...lab testing is completely useless for weak links?

-- range of gliders is put at the recommended one G by a single loop of Cortland 130 pound Greenspot braided Dacron Tolling line placed at one end of a shoulder bridle?

-- happens to gliders, if any, not put at the recommended one G by a single loop of Cortland 130 pound Greenspot braided Dacron Tolling line placed at one end of a shoulder bridle?

- It's TROLLING line - asshole. A TOLLING line is what forms behind a booth exiting a turnpike at the end of a holiday weekend.
---
2014/05/28 03:50:00 UTC

I seem to have accidentally and unknowingly submitted this one while it was still under construction and didn't catch the problem for quite some time. If you're reading this and interested please give things another review for fixes, changes, additions. Sorry 'bout that.

[Tad Eareckson]

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

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

The tow forces on the weaklink will be roughly divided in half by this placement.

Really?

http://www.questairforce.com/aero.html
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.

That's not what Quest Air says. And...

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

Davis Straub - 2011/07/30 19:51:54 UTC

I'm very happy with the way Quest Air (Bobby Bailey designed) does it now.

...you're very happy with the way Quest Air (Bobby Bailey designed) does it now.

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

Pilots will be shown how to tie the weaklink so that it more likely breaks at its rating breaking strength.

- So that it MORE LIKELY breaks at its rating breaking strength?

-- So that would be 260 pounds according to Quest/Bobby. Rating is 130, two strands - 260, knot positioned so that it's hidden from the main tension in the link and excluded altogether from the equation. And then you tell us - as Ridgely told me on their first weekend of operation - that its only seeing half the towline tension so 520 pounds. How many solo competition gliders do you know who are flying at 520 pounds? Sounds to me like you're putting a lot of gliders up at TWICE the recommended one G.

-- Define "MORE LIKELY". HGFA says that its testing indicated that the manner of tying does not greatly affect the breaking strain of the weak link - which is consistent with what EVERYBODY who ACTUALLY TESTS weak links have found. What did you find in YOUR testing?

-- What happens if it LESS LIKELY breaks at its rating breaking strength. Can the glider:

--- fold up or lock out if it breaks ABOVE its rating breaking strength?

--- be otherwise...

Manned Kiting
The Basic Handbook of Tow Launched Hang Gliding
Daniel F. Poynter
1974

"The greatest dangers are a rope break or a premature release." - Richard Johnson

...endangered if it breaks BELOW its rating breaking strength?

- Why the fuck can't you show us all NOW how to tie the weak link so that it MORE LIKELY breaks at its rating breaking strength - whatever the fuck that's supposed to be and accomplish - ASSHOLE? Are the only people worthy of being blessed with such important and critical safety information the dickheads who show up for your pecker measuring contests? These knots don't have names and you can't illustrate them?

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


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

Loop formed with a Fisherman's Knot. Installed on the bridle with a Double Lark's Head and on the thimble with a Single. You're too fuckin' brain damaged to do something like that?

This weak link must be a real focal point of a safe towing system and one G and consistent breaking strengths must be very important issues. Real bummer that you don't seem to be able to give us the slightest sane hint of an explanation as to how and why. Short version of the fourteen page dose of total rot Dr. Trisa Tilletti is gonna pour into the magazine in another half dozen years.

Why zero interest in issues of wheels, skids, eye protection, helmets, parachutes, gloves, protective clothing, inappropriate "bridles" that can blown in emergencies...? Guess there's not much space left after you've so thoroughly dealt with the weak link issue.
---
P.S. See note at the end of the previous.

[Tad Eareckson]

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

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

For many years...

How many years?

...a number...

How big a number?

...of us...

Who's US? Give us some names.

...(US pilots)...

You're not a PILOT. You're just some brain damaged asshole who flies a lot. And I can count the people in the US who qualify as hang glider PILOTS on one hand - and none of them would be on speaking terms with you.

...have felt that #8 bricklayers nylon line was not an appropriate material to use for weaklinks...

Course not. It would be totally out of sync with the high standards you set for your appropriate bridles.



And Wills Wing tells us to...

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.

...always use an appropriate weak link with a finished length of 1.5 inches or less. And how are ya gonna always use an appropriate weak link with a finished length of 1.5 inches or less if you're using #8 bricklayer's nylon line that some of you (US pilots) feel is not an appropriate material to use for weak links? Duh!

...as it is not as consistent in its breaking strength (as far as we are concerned)...

Well! As far as YOU'RE concerned. End of story. Fuck stuff like data when it conflicts with any totally clueless ASSUMPTIONS *YOU'VE* made. We should all be operating under the safety standards YOU'VE mandated for us because of your FEELINGS about stuff.

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

Kinsley Sykes - 2013/02/11 17:46:12 UTC

Because this has been beaten to death - google Tad Eareckson and try to read the mind-numbing BS. Most of the folks who have been towing for decades have worked this stuff out.

Fuck you, Kinsley.

...as the Greenspot line used in the US.

- Well yeah! If something is being used in the US it just has to be the best! If it weren't everybody would be using something else!

- OH!

-- So this was all about the FEELINGS of you and a few other unidentified incestuous US douchebags who are considered to be PILOTS and could stand to be within a fifty mile radius of you without blowing lunch and breaking out in a rash!

-- Not one of you disgusting pieces of shit bothered to TEST a single loop of 130 pound Greenspot with the knot positioned so that it was hidden from the main tension in the link and excluded altogether from the equation, thus yielding a rating of 260 pounds - plus or minus 0.3 percent.

-- You just FELT that this material would break more CONSISTENTLY at the load which:
--- Quest specified as being 260 pounds
--- you refer to only as its "rating strength"
--- Industry twats specify as whatever the fuck they feel like
--- 99.9 percent of the assholes in flight lines waiting for relights know puts each and every one of them at 1.0 Gs

-- Not ONE of you disgusting pieces o' shit had an IQ high enough up in the lower double digits to understand that weak links on TWO point bridles...

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

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?

...see fifteen percent more load than they do when pro toad.

-- You Industry twats FELT that the improvement in CONSISTENCY which would put everybody in the flight line - 200 to 350 pounds, two point and pro toad - within one percent of 1.0 Gs and thus make it WORK much better than what the Aussies were using.

-- With guns to your heads none of you motherfuckers will tell us:
--- what:
---- the purpose of the weak link is supposed to be
---- you mean by the word "work"
--- why one G has the very special significance it does for hang glider towing
--- who pulled one G out of his ass and decided that it should be "recommended"
--- why Nazi level enforcement of the 130 Greenspot standard aerotow weak link dwarfs or eliminates all other aerotow safety considerations
--- the horror stories resulting from people using weak links which broke inconsistently on the high side
--- the ACTUAL horror stories resulting from 130 pound Greenspot breaking consistently at one out of five tows

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.

At the 2009 Forbes Flatlands for the second time using 130 pound Greenspot as the standard weak link material (thanks in large part to the efforts of Bobby Bailey) and an Approved Bridle like this:



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.

...total piece of shit (thanks ENTIRELY to the efforts of Bobby Bailey and the other Questie shits who control this aspect of the sport), Steve Elliot, sailmaker for Moyes Delta Gliders, came off the cart crooked JUST LIKE THIS:

01-001

04-200

05-215


('cept without the cored out golf ball over the fat stubby little barrel so there was no point at all in attempting to release...

07-300

08-301

09-304


...not that releasing in the time it takes to complete the easy reach is gonna do ya much good anyway), slammed in JUST LIKE THIS:

11-311

15-413


'cept a little harder, and was choppered out with a broken neck to die in an induced coma in Sydney two days later.

And NOBODY is gonna ask the slightest hint of a question about why:
- he was unable to abort the tow
- his standard aerotow weak link didn't work the way it was supposed to

And if he'd been flying one of Tad's home made inappropriate aerotow bridles and/or a heavy one and a half G Tad-O-Link I one hundred percent guarantee you that there'd have been an international feeding frenzy which would've totally dwarfed what we saw after Jon Orders dropped Lenami and swallowed the video card.

I wonder who was driving the tug? Any chance it was the same dude who was driving the tug when Robin Strid was killed by the appropriate bridle everybody and his dog uses - including people and dogs who fly tandem with other people and dogs (thanks in large part to the efforts of Bobby Bailey)?

http://www.flickr.com/photos/aerotowrelease/8318769461/