Weak links

General discussion about the sport of hang gliding
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Tad Eareckson
Posts: 9153
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

I got asked by the then Towing Committee Chairman to...
Gregg Ludwig - 2009/02/12 00:05:51 UTC

ushpa Tow Committee opportunities

Tad-

Would you be interested in a position on the ushpa Tow Committee? You can participate via e-mail if you can't make it to a BOD meeting. ..or just help me with a single project...

I need to rewrite the aerotow SOP...to include ATP and Sport pilot stuff....weaklinks...or just send me a proposal on weaklink sop ideas...

Gregg
Tow Committee Chair
...help rewrite the useless fucking USHGA AT SOPs...

I rewrote the useless fucking USHGA AT SOPs...
Bill Cummings - 2012/01/10 14:04:59 UTC

Tad's procedures for aerotowing should become part of any training manual.
Tad must have put hour upon hour of gathering together his written procedure.
...into something what would've made aerotowing sane, safe, efficient, fun, and would very likely have kept that bozo alive at Quest a little shy of two weeks ago - and they and I got treated like we didn't exist.

When I went up the chain of command...
Subj: Re: [Tow] AT SOPs - proposed revisions
Date: 2009 May 09 22:10:38
From: cloud9sa@aol.com
To: skysailingtowing@yahoogroups.com
cc: GreggLudwig@aol.com, lisa@lisatateglass.com

Hi Tad.

I'm Tracy Tillman, on the USHPA BOD, on the Tow Committe, and I am an Aviation Safety Counselor on the FAA Safety Team (FAAST) for the Detroit FSDO area. As a rep of both the USHPA and FAA, I would like to help you, USHPA, and the FAA improve safety in flying, towing, and hang gliding.

The FAA gets a lot of letters of complaint from a lot of yahoos...
I got nothing but attacked by these stupid evil pigfuckers who've hijacked the sport.
And from that point on they've done nothing but the precise opposite of what was and is needed.
We need to get control of this sport back from Tim Herr and these USHGA scumbags.
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Tad Eareckson
Posts: 9153
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks
Gerry Grossnegger - 2013/02/14 06:09:09 UTC

"a stronger weak link" than what? A loop of 130lb Cortland Greenspot?
What else could an aerotow weak link POSSIBLY be? Name ONE THING that's got a hundred thousandth of a track record that huge.
Daniel Velez - 2013/02/14 23:25:34 UTC

It's quite difficult to put risk management as a poll.
Why? You just get everyone's opinions and do whatever is most popular. And if anybody gets in the way with physics or anything else unpleasant and/or inconvenient you just ban him and take another poll.
The problem is that what's safer for an accidental low weaklink break is not safer for a non breaking lock out situation...
Yeah, that's why God gave some of us the ability to put devices on our gliders to allow us - as PILOTS - to execute decisions about whether to stay on or abort tows.
...so probably the risk management will led you to conclude that usually one has more incidents of low accidental breaks that lead to a hazardous but uneventful situation than breaking a weaklink during a life and death lock out situation...
Ask Zack Marzec how uneventful his situation was.
This means that the probability of having a problem with an accidental break is more common than having a problem with the lockout. So by probabilities, stronger or not at all weaklinks would be the way to minimize events, but also will lead to tragical lockout situations. So risk management would end up saying that it's better to have a lot of small low speed level wing crashes than one single high speed high bank angle lockout crash...
Earth to Daniel... Earth to Daniel... Come in Daniel...
I'm not a towing expert...
Good. That'll make one less pike we need on which to impale a severed head.
...but I feel confident from the 130 lb weaklink...
Great. In a sport that's all about opinions and feelings you'll fit in just fine.
I'm a light pilot...
Like Zack?
...and it tows me on hard conditions with low breaking events (maybe 5% failures)...
So a:
- one in twenty chance of a potentially lethal equipment failure in the most desirable flying conditions
- 95 percent success rate in maintaining your status as Pilot In Command and executing a flight plan

Keep up the great work, dude!
...and on the only one time that things where getting a little out of control (locking out when Bobby cored to hard on the tow plane) it broke as it was supposed to.
- Locking out - I got news for you - is NOT getting a LITTLE out of control. It's getting TOTALLY out of control. It's progressing to a point at which the tow's over. And you can expect to drop like a brick...

Hang Glider Lock-Out!
http://www.youtube.com/watch?v=fnrh9-pOiq4
MorphFX - 2011/03/20
A hang glider pilot learning to aerotow starts a mild PIO that leads into a lock-out.
dead
02-00319
http://farm8.staticflickr.com/7523/15601000807_705ab49977_o.png
Image
Image
http://farm6.staticflickr.com/5606/15600335029_3c234e6828_o.png
14-03708
http://www.kitestrings.org/post6995.html#p6995

...for a while after its conclusion - especially of you wait for your 130 pound Greenspot Pilot In Command do your job for you.

And whether or not you and your glider survive is determined entirely by altitude (read luck).

So lotsa luck, dude.

- The fucking weak link is *NOT* "SUPPOSED TO" break in a lockout - and anybody who told you it was should have his balls cut off and shoved down his throat. It will, eventually, break in a lockout IF you don't slam in first. But, contrary to what you hear all the time from shitheads like Rooney and Ryan and as noted above, there may not be a lot of difference between the consequences of a weak link holding all the way to impact or having it pop a couple hundred feet above impact.

- The fucking weak link is SUPPOSED to break when the line tension exceeds its strength - and will, in fact, do that with one hundred percent reliability. Any other statement about what its SUPPOSED to do is bullshit.
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks
Davis Straub - 2013/02/15 00:34:35 UTC

Bobby never cores too hard. The hang glider pilot just doesn't keep up with him.
Yeah...

http://ozreport.com/3.066
Weaklinks
Davis Straub - 1999/06/06

During the US Nationals I wrote a bit about weaklinks and the gag weaklinks that someone tied at Quest Air. A few days after I wrote about them, Bobby Bailey, designer and builder of the Bailey-Moyes Dragon Fly tug, approached me visibly upset about what I and James Freeman had written about weaklinks. He was especially upset that I had written that I had doubled my weaklink after three weaklinks in a row had broken on me.
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3661
Flying the 914 Dragonfly
Jim Rooney - 2008/12/06 20:01:49 UTC

You will only ever need full throttle for the first fifty feet of a tandem tow. Don't ever pull a solo at full throttle... they will not be able to climb with you. You can tow them at 28 mph and you'll still leave them in the dust... they just won't be able to climb with you... weaklinks will go left and right.
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.)
Go figure.
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec
Deltaman - 2013/02/08 13:57:01 UTC

What lacks to your friend Zack is a good understanding of what should be a weaklink..
Its purpose is not to protect the pilot as every ranches are saying but just to protect the glider from overload.
Davis Straub - 2013/02/08 16:57:42 UTC

All the flight parks that I am aware of are quite aware of this. They tell their pilots that the point of the weak link is save the glider from overload and that they should not rely on the weaklink to save them.
A little more on this outrageous bullshit statement, Davis...

http://www.wallaby.com/aerotow_primer.php

Wallaby...
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.
Ridgely...

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Jim Rooney - 2011/08/26 02:44:10 UTC

The "purpose" of a weaklink is to increase the safety of the towing operation. PERIOD.
http://www.hanggliding.org/viewtopic.php?t=17404
Aerotow barrel release - straight or curved pin?

Manquin...

http://www.hanggliding.org/viewtopic.php?t=17404
Aerotow barrel release - straight or curved pin?
Jim Rooney - 2010/05/31 01:53:13 UTC

BTW, Steve Wendt is exceptionally knowledgeable. Hell, he's the one that signed off my instructor rating.
Steve Wendt - 2007/03

Blue Sky Scooter Towing Method, Equipment & Practices.

But with the towline we use a standard weak link like we would for aerotow...
Lookout...
Lockouts can be prevented by using good technique, light tow pressures, and appropriately-sized weak links--if you get too far off heading, and a lockout begins to develop, a proper weak link will break and release you from tow.
Cloud 9...
We want our weak links to break as early as possible in lockout situations, but be strong and reliable enough to avoid frequent weak link breaks from turbulence. It is the same expectation of performance that we have for the weak links we use for towing sailplanes.
Quest...

http://ozreport.com/forum/viewtopic.php?t=24534
It's a wrap
Lauren Tjaden - 2011/08/01 02:01:06 UTC

For whomever asked about the function of a weak link, it is to release the glider and plane from each other when the tow forces become greater than desirable -- whether that is due to a lockout or a malfunction of equipment or whatever. This can save a glider, a tow pilot, or more often, a hang glider pilot who does not get off of tow when he or she gets too far out of whack.
Cowboy Up...

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Bart Weghorst - 2011/08/28 20:29:27 UTC

Now I don't give a shit about breaking strength anymore. I really don't care what the numbers are. I just want my weaklink to break every once in a while.
It's pretty fuckin' obvious that there's not a single mainstream Dragonfly operation that has a goddam clue what the purpose of a weak link is and is able to think of it and teach people to think of it as anything other than lockout protection for the pilot.

And lemme tell ya, motherfucker...

http://www.hanggliding.org/viewtopic.php?t=26870
weak links
Davis Straub - 2012/08/13 18:08:42 UTC

Used to do 130 lbs. Now do 200 lbs.
Anybody who's using 130 or 200 on a bridle end on ANY glider is NOT using it to protect the glider from being overloaded.

And let's look at just how this "standard aerotow weak link" bullshit...

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec
Jim Rooney - 2013/02/13 19:09:33 UTC
Can you explain, then, exactly how we arrived at the current 130 lb weak link standard?
It was already worked out by the time I arrived.
...was worked out before Jim Keen-Intellect Rooney descended from the heavens to save all of humanity from the lunacy of Tad and anybody else capable of adding two plus two and getting four.

From this link:

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

that was up forever before going dead maybe four years ago...
Quest Air
Aerotow FAQ

Equipment and Accessories

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 the entire history of and extent to which Bobby Fucking-Genius Bailey and the rest of those Quallaby assholes experimented, worked things out, and established this damnable piece of fishing line as Pilot In Command of untold hundreds of thousands of flights - a HUGE percentage of them ending unsuccessfully and much worse...

- Saying that the strength of the weak link is crucial to a safe tow is like saying that the capacity of the parachute or shock absorbing quality of the helmet is crucial to a safe tow. A weak link, parachute, or helmet ONLY become relevant AFTER the pooch has been majorly screwed and shouldn't be counted on to do much good.

The fuckin' weak link is the first thing you'd throw away from your towing system if you were forced to make a sacrifice because it's something you're extremely unlikely to ever need - in contrast to a release which you're gonna need and use EVERY flight.

- These assholes were and are totally incapable of working out the difference between TENSION and PRESSURE.

- There's no such thing as a weak link which is capable of both strong enough to get a glider airborne and weak enough so that a MISALIGNED "pressure" can't compromise the glider's handling enough to kill it in a heartbeat.

- This shit fishing line that these assholes tried to use to achieve this totally fictional goal not only can't handle the least bit of rough air but frequently blows with the glider straight and level in smooth air on medium weight glider and virtually guarantees a kill in a Zack Marzec situation for any glider you wanna name.

- The "good rule of thumb" of one G is a figure that Donnell Hewett pulled out of his ass in 1980 under the INSANE ASSUMPTION that a glider on tow couldn't get into too much trouble with that limitation. (Big thanks to Zack Marzec here for demonstrating just how insane that assumption and rule of thumb was.)

- People who aren't total shitheads understand that weak link rating has NOTHING to do with "the total WING LOAD of the glider" and EVERYTHING to do with the LOAD CAPACITY of the glider.

- There's no fucking such thing as an "optimum" weak link strength because you can't predict what will happen in an emergency / compromised control situation as a consequence of a blow or a continuation of the tow but around one and a half Gs is a reasonable compromise. That's strong enough to pull you through some pretty ugly situations and weak enough such that the combination of stresses on the glider - flying weight, tow tension, centrifugal force - are unlikely to exceed three Gs.

- Most flight parks use 130 pound braided Dacron line because the kinds of low double digit IQ folk running the flight parks just blindly follow whatever moronic precedent Bobby Fucking-Genius Bailey sets.

- And the moronic precedent Bobby Fucking-Genius Bailey set in this particular instance is based upon that shithead's ASSUMPTION that a Bobby Loop blows at twice the value it does when you go to the trouble to TEST it.

- And Bobby Fucking-Genius Bailey is also too astoundingly stupid to understand that using a bridle to split the load between the pilot and glider or between two attachment points on the pilot's shoulders reduces or halves the strain on the weak link.

- And Bobby Fucking-Genius Bailey is also too stupid to understand that using a bridle to split the load between the pilot and glider necessitates a bridle with a significant apex angle and that introduces a significant increase above half towline to the strain on the weak link.

- And after we've gotten all of the above layers of pig shit ladled onto us we're only concerned about the "TYPICAL" glider - which as we all know, weighs 260 pounds. So we really don't need to worry about 180 and 360 pound gliders. 130 pound Greenspot is "optimal" for them so fuck everybody else.

- As Bobby Fucking-Genius Bailey and his shitheaded buddies are too fucking stupid to be capable of understanding the difference between TENSION and PRESSURE (pounds and pounds per square inch) they are likewise too fucking stupid to be capable of understanding the difference between FLYING WEIGHT and WING LOADING (pounds and pounds per square foot) and that while the flying weight of a tandem tends to be (but isn't always) a lot greater than a solo the wing loading stays around the same.

- And Bobby Fucking-Genius Bailey and his shitheaded buddies are assuming that an average tandem weighs two average solos. It DOESN'T - it weighs considerably less.

- And Bobby Fucking-Genius Bailey and his shitheaded buddies are assuming that the optimal weak link for a solo is twice what they have so meticulously "worked out" is the optimal solo weak link.

- And Bobby Fucking-Genius Bailey and his shitheaded buddies are assuming the way to achieve this optimal tandem weak link is to double the optimal "260" pound solo weak link to get 520 pounds. In reality it blows at around 200.

- Following this lead, operations like Ridgely which were smart enough to realize that when you split the load with a bridle the weak link doesn't see the full load but too stupid to realize that bridle tension goes up with apex angle believed they were towing at 1040 pounds when in fact they were towing at 348, a reality a third of the fantasy world they had fabricated for themselves - and us.

- Anybody who's done any actual TESTING knows that these schemes to "position the knot so that it's hidden from the main tension in the link and excluded altogether from the equation" are bullshit. Loop weak links installed on typical aerotow bridles break at bridle strains around the test rating of the material - regardless of where the fucking knot is "positioned".

- The first time ANY of the assholes in this industry had a clue what kind of tension a tug was pulling on a solo flight is when I took my gear up behind a 914 Dragonfly in the spring of 2007 and got 125 regular and 155 turbo.

- The ONLY statements in that drivel that aren't total crap are that:
-- most flight parks use 130 for solos; and
-- double loops are used for tandems.

- And note that the ACTUAL PURPOSE and ONLY POSSIBLE RELIABLE FUNCTION of the weak link...
Tost Flugzeuggerätebau

Weak links protect your aircraft against overloading.
...ISN'T EVEN MENTIONED OR SO MUCH AS HINTED AT.
Davis Straub - 2013/02/08 16:57:42 UTC

All the flight parks that I am aware of are quite aware of this. They tell their pilots that the point of the weak link is save the glider from overload and that they should not rely on the weaklink to save them.
Sure Davis. Whatever you say.

This, kids, is the ENTIRE HISTORY of...
Jim Rooney - 2013/02/12 18:00:27 UTC

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?
Jim Rooney - 2013/02/13 19:09:33 UTC

It was already worked out by the time I arrived.
The reason it sticks?
Trail and error.

Every now and then someone comes along with the "new" idea of a stronger weaklink. Eventually, they scare themselves with it and wind up back with one that has a very proven track record. I mean really... no exaggeration... hundreds of thousands of tows.

Say what you will, but if you want to argue with *that* much history, well, you better have one hell of an argument... which you don't.
...how this stuff was already worked out by the time Jim Keen-Intellect Rooney arrived. An asshole in Florida made a whole bunch of idiot bullshit assumptions, put into a formula a loop of fishing line he thought would fit the bill for the fantasy world his substandard deranged little brain had concocted, and forced everybody to fly with to the exclusion of anything else for the past couple dozen years REGARDLESS of the results he was getting.

We have to gut these motherfuckers and get things back under control NOW.
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=31053
Poll on releases
Deltaman - 2013/02/15 08:24:44 UTC

Sorry but ask by poll on releases and poll on weaklink in two differents threads isn't the right way.
A thought on the weaklink calibration is undissociable with the choice of the release.
That's why I would prefer that :

Would you prefer to use a release..

1 - that works everytime at all loads with few effort
with a quick actuation lanyard already in your hand or mouth, that let your both hands on the basebar
..WITH a reliable (strong) link with the tug

2 - with a bent pin, at least 3.5 times heavier to release, that need you to quit the glider control an instant and get worse
..WITH a weak weaklink that cannot prevent attitudes that could be catastrophic near the ground but can break uselessly and dangerously more often, at any times you don't want, and force you to take risks of a take off and a landing at least 2 times, and will cost you more..

3 - that works everytime at all loads with few effort
with a quick actuation lanyard already in your hand or mouth, that let your both hands on the basebar
..WITH a weak weaklink that cannot prevent attitudes that could be catastrophic near the ground but can break uselessly and dangerously more often, at any times you don't want, and force you to take risks of a take off and a landing at least 2 times, and will cost you more..

4 - with a bent pin, at least 3.5 times heavier to release, that need you to quit the glider control an instant and get worse
..WITH a reliable (strong) link with the tug
Quinn Cornwell - 2013/02/15 15:57:43 UTC

You don't like it, run your own poll. Any user can do it.
Yeah Quinn, let's dilute this issue and confuse people as much as we possibly can to make sure our hallowed Greenspot stays enshrined in our operations for all eternity.
By the way, I stopped reading half way through your first poll option.
Of course you did, you useless goddam brain dead little shit. Took me about twenty seconds and that would be 33 percent over your normal fifteen second attention span. It's a fuckin' miracle you made it as far as you did.
I'm guessing most people will.
In Davis's intellectually castrated little cult screened out of public view? No doubt whatsoever?
Polls should be short and simple.
http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Davis Straub - 2011/08/26 14:04:52 UTC

Greenspot is now black.
Which 130 pound Cortland Dacron braided fishing line do you think makes the better aerotow weak link?

A) Green.
B) Black.
C) Dark green - if they ever make it available.
D) Heck I don't know, I just use what they gave me.

Fuck you, Quinn. Your second grade teacher needs to be hunted down and have a stake driven through her heart.
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks
Brad Gryder - 2013/02/15 16:09:46 UTC
Foothills Flight Park
Hiddenite, North Carolina

Dang it, globalwarming, or whatever the cause.
The tadpoles came out early this year. :(
Fuck you too, Brad.
Zack C
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Re: Weak links

Post by Zack C »

Take your theory and shove it. The shit works in reality. Seriously...hundreds of thousands of tows.

So did Bobby introduce Greenspot? I've got no information on how it came into use.

Awesome post, by the way (3740).

Zack
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

Take your theory and shove it. The shit works in reality. Seriously...hundreds of thousands of tows.
Theory free, opinion poll and track record based aviation. Just what we need.
So did Bobby introduce Greenspot?
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.
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

The tow line to release interface

Jim, as I am starting to play with Elektra Tow (ET) at Quest Air (the battery powered "scooter" tow system you and Adam got me jazzed up about up at Highland) I've watched this thread closely. We all can learn.

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.
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.)
The Wallaby and Bailey "releases" are his. I can't, with what I have now CONFIRM that he was the first asshole to slap it on behind a Dragonfly, but if I had a gun to my head I wouldn't worry too much about saying Bobby. He's revered as a God, he and Bill Moyes were forcing everybody up on insanely light stuff immediately post Robin Strid, he's never done a goddam thing to disclaim credit, and he's never done a goddam thing to get any heavier weak links or better equipment into the air.

And he's been as silent after Zack Marzec as he was after he pulled Robin to his death.
Awesome post, by the way (3740).
- With material from Quest THAT GOOD this stuff rights itself.

- Thanks. Took me DAYS with all the interruptions from stuff coming off the wires. I'm totally exhausted - constantly now. (And for the period around Zack's final weekend I was dealing with The Abscessed Molar From Hell plus a fairly considerable flu thing on top of it. I'm just about back up to speed now.)

Keep the heat on. There's a not inconsiderable chance that you could dethrone all these frauds and Ponzi schemers and emerge as THE English speaking world authority on aerotowing - especially if you keep getting some of the covering fire (miguel) you have been.

And I think that Antoine has a pretty good beachhead in continental Europe. (That's cheating a bit though. I don't think he's got a tiny fraction of the entrenched stupidity and corruption to deal with that we do.)
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Tad Eareckson
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Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec
Davis Straub - 2013/02/15 04:39:38 UTC

I remember back to January 1997.
I remember back to 1957 - but I haven't had as many concussions as you have.
I was at the pre-Worlds in Forbes. We had just received a shipment of Laminar ST's from Icaro 2000. No one had flown them before so they were all new to us. I was aerotowing.

The first day I took, if I recall this correctly, seven tows. They were all very exciting. I broke the weak link every time.
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.
Davis Straub - 2011/08/28 15:26:28 UTC

We couldn't figure out why we had so many breaks so quickly. Maybe just coincidence.
http://ozreport.com/forum/viewtopic.php?t=27494
The exciting bits
Steve Davy - 2012/04/27 03:13:52 UTC

Kinda seems like you guys that do a lot of towing would be able to figure this out. Guess not.
Davis Straub - 2012/04/27 11:51:33 UTC

I wrote about Zapata because what happened is very unusual.
Define "unusual", Davis. My concept seems to be a bit at odds with yours.
Don't remember exactly what the weaklink was.
- Lessee... You blew the weak link SEVEN times IN A ROW and you don't remember exactly what it was. I think I'm starting to ping in on part of the problem here.

- What do you "THINK" they were, asshole?

- Hell, none of you fucking assholes had the slightest clue what the Sacred Loop was doing until...

http://ozreport.com/9.049
Weaklinks
Davis Straub - 2005/03/01

The standard in the US is 130 lb test line in one loop with a fisherman's knot.

We were thinking and talking about weaklinks the other day here at Quest Air, given all the discussion about them on the Tow Group on the Oz Report forum and in the Oz Report since the Worlds (search for '"Volume 9" weaklinks' in the Oz Report search box).

Steve Kroop, Bob Lane, and Rhett Radford decided to do a few quick and dirty tests just to see if a looped 130 lbs test line (IGFA DACRON TROLLING LINE) would hold 260 pounds with or without tying the loop so that the knot was "hidden."

We looped one end of a weaklink loop to the loop of a spectra bridle (part of a pro-tow and available here at Quest Air) and the other end to a loop of webbing approximately as thick as the loops that you would find on the shoulders of your harness. Tying the spectra to the hang gliding real life simulator outside the Quest Air and Flytec office entrance, Steve Kroop, and then Rhett Radford, slowly raised themselves up from a seated position by slowly pulling on the loop.

The weaklink broke before they were able to get their weigh off the ground. Steve and Rhett are quite a bit less than 200 pounds. The weaklink broke whether the knot was hidden or not.

Therefore I assume that the single loop of 130 lbs test line is providing a weaklink strength of about 1/2 G , about 120-150 pounds.
...over eight years (and how many tows - yours and all the ones you set policy for?) later.
Pretty sure it was protow.
No doubt, Mister Pro Toad. MUCH safer - especially when you're having problems with new batches of gliders.
All the breaks, except maybe one or two were up high enough to allow me to fly back to the launch spot and try again.
Great! So...
- How bad were the five or six lockouts up high that necessitated these blows?
- Good job handling the one or two low level lockouts. Takes a real pro to survive stuff like that.
- How come you weren't able to get to your Davis Mini Barrels in any of those incidents?
I recall a number of them seemed to happen with the glider doing dutch rolls.
So what G rating weak link do you think we should use to prevent Dutch rolls?
I remember holding on and doing my best to keep the glider upright and flying behind the Dragonfly and then instantly I would be turned 90 degrees in a roll.
Ninety degrees?
Towing Aloft - 1998/01

Speed controlled towing is when the speed of the device doing the towing is maintained at a reasonably constant value. Controls, such as throttle, are used to keep the speed of the tow vehicle or tow winch operating at a constant speed. Towline tension can vary dramatically in response to thermals, sink, pilot corrections, etc. Aerotowing is clearly in this category as the tug needs to maintain a minimum speed to prevent stalling. Many of the early towing efforts of the '70s where the vehicle drove at a fixed speed would also fall into this category. Weak links very clearly will provide protection from excessive angles of attack, high bank turns and the like for this form of towing.
DUDE! Too bad you didn't get that info to the authors of the excellent book, Towing Aloft, before they went to press with it.
How I kept towing seven times I have no idea.
You didn't.
The first day I took, if I recall this correctly, seven tows. They were all very exciting. I broke the weak link every time.
So how far rolled were you - if at all - when your weak links blew?

So what the fuck does any of this hafta do with the issue of weak links and Zack Marzec other than to add to the mountain of evidence that what USHGA and all your pigfucker flight buddies are feeding people is a crock of shit, that there's no such thing as a weak link which will blow to keep you from getting rolled on your ear but hold when you're under control and trying to complete the tow?
User avatar
Tad Eareckson
Posts: 9153
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

http://ozreport.com/forum/viewtopic.php?t=30971
Zach Marzec
Zack C - 2013/02/14 06:27:16 UTC
Marc Fink - 2013/02/13 16:20:07 UTC

Generally the argument boils down to whether or not the pilot would be better off staying on tow during an incipient lock-out or other situation where the glider is significantly "out-of-line" with the tug, the reasoning being that a failure at that moment makes the glider vulnerable to catastrophic stalls etc.
I don't think so. It's usually better to get off the line sooner in a bad situation than later. Weak link breaks are primarily a danger when they occur near the ground when the glider's angle of attack is high. The glider doesn't have to be in an incipient lock-out or significantly "out-of-line" with the tug for its angle of attack to be high - hitting strong lift is enough to do it.
REALLY? Can you cite a real life example of something like that happening?
If a requirement for stronger weaklinks were promulgated for all solo aerotowing--I'd immediately stop aerotowing.
Well, 130 lb weak links are in violation of FAA regulations for pretty much everyone towing two (three) point and many towing one point (pro tow)...
We'll be expecting your resignation in tomorrow's mail. Don't let the door hit you in the ass on your way out.
Jim Rooney - 2013/02/13 19:09:33 UTC

The shit works. It works in reality and it works consistently.
Works to do what? If by 'works' you mean ensures an efficient operation by getting pilots to altitude reliably...
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.
...we disagree. If by 'works' you mean protects pilots from unusual attitudes...

http://www.youtube.com/watch?v=27yFcEMpfMk


...we disagree. (That flight ended in a release...the weak link did not break.) If by 'works' you mean keeps the glider from breaking, sure, but you could use much stronger stuff for that job.
Oh, ferchrisake Zack. How can I explain this to you?
- This stuff's been worked on and worked over for years and THOUSANDS upon THOUSANDS of tows.
- It's kept because it has a huge track record. That's really hard to argue with. I've yet to hear anyone successfully do so.
- We've got a proven system that works.
- It stands the test of reality.
- It's manufactured. It's a common and standard material. You can get it at a fishing store and everyone knows what it is.
- It works a hell of a lot better than all the other bullshit I've seen out there.
- That other bullshit is the fire that the "other side" is made of. Best not to play with it.
- Some of that other bullshit even has a number of tows behind it... but hundreds of thousands is a very large number.
- If anything worked better, we'd be using it everywhere.
- I have no desire whatsoever to have a pilot smashing himself into the earth on my watch.
- I've had these exact same arguments for years and years and years. Nothing about them changes except the new faces spouting them.
- I get tired as hell "refuting" all these mouth release and "strong link" arguments.
- I just buried my friend and you're seizing the moment to preach your bullshit? GO FUCK YOURSELF!!!!!!!!
- There is NOTHING out there that performs like 130 pound Cortland Greenspot better than 130 pound Cortland Greenspot.
Every now and then someone comes along with the "new" idea of a stronger weaklink. Eventually, they scare themselves with it and wind up back with one that has a very proven track record.
I guess we can expect Davis will scare himself eventually.
I wonder if he'll scare himself as much as a pro toad who has a tail slide at 150 feet after pitching up in a monster thermal.
You can scare yourself pretty easily waiting for a 130 lb link to break...

http://www.youtube.com/watch?v=F_n5B3-MIC4


...and have no issues waiting for a 'strong' one to break.
deltaman - 2012/05/25 19:45:39 UTC

I miss opportunity to be aerotowed in my mountains but 2 months ago we spent 4 days teaching AT to 12 pilots in 2 points. All had 190kg weaklink (220kg on tug side).
One of them oscillate and start to lockout. I said by radio : (time to) release, he did it (JoeStreet release), but 1ms to late.. the weaklink was just blowed.
and no unexpected wl failure in 90 AT.
I'm confident in this way to think wl..
Hey Deltaman.
Get fucked.
Why? Because lockouts are a function of alignment, not tension, and weak links can only limit tension. Yes, tension will eventually increase in a lockout and eventually break the weak link, but there's no telling what the glider's attitude will be when that happens - no matter how weak your weak link is. A stronger weak link might make the required recovery altitude a little greater. Thus, there's only a narrow lockout altitude range in which the weak link strength even matters - below that, waiting for either weak link to break results in a crash; above that, the glider has enough altitude to recover if either weak link breaks.
Another possibility...

The glider's in a climbing lockout - in which case the pop and recovery altitudes could be higher for some of that other bullshit I've seen out there.
By using a stronger link I wager I won't need it to break in this altitude band in exchange for not having to worry about it breaking at a bad time. But whatever I use as a weak link, I make sure I'll never have to rely on it anyway by using a good release - because relying on any weak link can be fatal.
And, if Zack's opinion upsets you, shop around until you find somebody who tells you what you wanna hear.
Jim Gaar - 2013/02/13 19:59:19 UTC

After 5 years as Safety and Launch Marshall for Adventure AirSports and towing (with a Dragonfly 582 BH) every type of wing class available on 3 different styles of carts and using Pro-tow and COM bridles and over 400 incident and accident free tows I feel it's pretty much the standard.
So I take it you arrived at that conclusion after extensively testing stronger material and finding it was less safe?
Oh yeah, right. Like if everybody just did stupid shit like that 130 Greenspot would have the huge track record it does now?
Bill Cummings - 2013/02/13 20:04:07 UTC

Lighter pilots with lighter gliders may worry that they may be pitched into a break stall with the breaking of the too strong of a "standard" in their case.
Are you implying that lighter weak links provide protection from excessive angles of attack? Is it not apparent from Zack M's incident that this is not the case? There's nothing stopping a glider's angle of attack from getting high prior to a spike in tension - and when that spike happens, the last thing you'll want is for the weak link to break.
Be gentle with him. His exposure to Hewett Theory has been a lot longer than most of the rest of us have endured.
If the flight parks insist on the use of a standard, each pilot still has the ability to blow the pilots weaklink with more tow force or less tow force just by increasing or decreasing the length of the shoulder to shoulder pro tow bridle.
Because of its already narrow apex angle, increasing the length of the shoulder bridle will make no significant difference in the tension of each bridle strand. (And the longer a bridle, the greater the chance of it wrapping on the tow ring/primary bridle.)
And his high school physics teacher really sucked.
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