Weak links

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

Re: Weak links

Post by Tad Eareckson »

http://www.hanggliding.org/viewtopic.php?t=36636
What is it?
Butch Peachy - 2019/11/09 02:28:49 UTC

Mike Haley, I remember him from 1990s when he worked for UP in Utah. He OKed my sponsorship when Tony Barton and Dave Sharp were the other UP team pilots. We flew the all carbon TRX 160. I didn't know Mike Haley had anything to do with truck towing.
I did static towing in Michigan. That is a setup were a vehicle drives toward you with a long 2000 ft. line that goes through a spindle and out to the pilot. The vehicle has a pressure gauge to monitor line tension as they pull a foot launch pilot into the air.
I was showed how to tie my own weak link which broke as it should on my first ever tow launch attempt .
The second and third launches were successful.
The third tow was into a light rain squall. The vehicle pulled me up. I was kited up in 15-20 wind. The tow vehicle ended up backing up while they watch the pressure gauge. I didn't release off of the tow line as I got higher as they backed up giving me more payout line. After 15 mins on the kiting tow, I was just under the low 1800 ft agl raining cloud base. Again it was a 2000 ft. tow line
The next day my weak line broke at 1000 ft. but I turned downwind and climbed out from 200 ft or so. I flew from central Michigan to Canada 130 miles away.
The first comp I flew for UP was out of Hobbs, NM. The tow system was a truck driving down a runway with a payout winch.
As some of us know, the critical part is the pilot release off the bed of the truck. I hate the initial release. It is like a high wind 4 wire man launch off a cliff. I called it "shotgun launch".
"Ka Bam!"
There are so many things you have to pay attention to in truck towing besides keeping the wings level.
I was first to the 100 mile goal north to Texas. The next pilot landed 45 mins later. Because we were timed from when we got off tow, I was not the fastest to goal.
The only thing I hate more than payout winch towing is added maneuver of step towing. This is were the tow vehicle has to turn around while the pilot is on tow. The purpose is to get more height on a short runway.
You watch the tow vehicle make the 180 degree turn as the line starts to go slack. During the slack time the pilot on tow continues in the opposite direct of the vehicle to minimize the line slack. When the slack is starting to be taken up by the tow vehicle, the pilot now turns 180 degrees and in the new direction of the tow vehicle. Still there is a strong tug and off we go together.
John Heiney and I were contacted to demonstrate the air pressure ballistic rocket to deploy an emergency parachute for a TV show. We had to use step towing with 2-3 turns.
I also hate coming down under half open canopy with a flying glider driving downward way faster than the FAA minimum descent rate of 15 ft a second.
"Ka Slam!"
I did static towing in Michigan. That is a setup were a vehicle drives toward you with a long 2000 ft. line that goes through a spindle...
It goes through a fuckin' PULLEY.
...and out to the pilot.
- Instead of doing things right with a platform payout rig.
- What pilot? A dope on a rope who only survives his first tow because his properly tied own weak link which broke as it should have?
The vehicle has a pressure gauge to monitor line tension as they pull a foot launch pilot into the air.
- Great! So if the line "tension" (we call it pressure now) is right on the money we know the glider's doing fine.

Bullshit. This is Skyting Criteria total crap. "Constant Tension". How many hundreds of thousands of AT launches - in which no one had the slightest clue what was going on with tension (before I went up and measured it myself) and it could jump all over the place in thermal turbulence - did we need to do to discredit that rot?

Whenever you're looking at the fuckin' gauge you're NOT looking at the fuckin' glider. And we have that issue on tape from two camera angles for the 2012/10/03 Bob Buxton Perfect Storm event:

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Fatal - for all intents and purposes. This is analogous to staring at your speedometer to verify that you're driving safely. Pure unadulterated distraction. Legitimate use of gauges: prior to launch to get the pull in the right ballpark and after the glider's well up and out of the kill zone to optimize climb. Pity Sean Buckner put major resources into his goddam gauges and total zilch into a glider release that didn't stink on ice.

- Fuck...

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...foot launching.

- Obvious use of a Tad-O-Link in the above launch. Either that or it was tied improperly such that additional strength was imparted to the fishing line. Any comment anyone?

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The properly tied weak link knew that Robin would be able to salvage this one?
I was showed how to tie my own weak link which broke as it should on my first ever tow launch attempt .
- GREAT!!! Outstanding success! Well done! On your very first effort! Just imagine what would've happened if it HADN'T broken as it should've.

- Any chance you could describe the manner in which you tied your own weak link to achieve such instantaneous and stellar results? 'Cause all the ways people have been tying them subsequently totally suck at performing this function.

- So the only reason you're still alive to tell the tale is because your properly tied weak link broke as it should on your first ever tow launch attempt. But this incident isn't worth your time to recount here. Much more important to tell us how successful your second and third launches were. Bullshit.
The second and third launches were successful.
- As opposed to your ULTRA successful first one.

- Thanks for confirming for us that your first effort was a FAILURE and a FAILURE for only one reason. And if we look at your overall percentage you're at a bit under 67 seven percent. And back when I was in school seventy was the lowest you could go for a D minus.
The third tow was into a light rain squall. The vehicle pulled me up. I was kited up in 15-20 wind. The tow vehicle ended up backing up while they watch the pressure gauge.
What was the pressure gauge reading when your properly tied weak link broke as it should on your first ever tow launch attempt? And how come we never seem to have reports on these figures?

If your truck had a pressure gauge then why did they tow you - a first-timer - all the way up to/through redline?
I didn't release off of the tow line as I got higher as they backed up giving me more payout line.
More PAYOUT line? Then how was this a static tow?
After 15 mins on the kiting tow, I was just under the low 1800 ft agl raining cloud base. Again it was a 2000 ft. tow line
So how come your weak link held as it should've through all of that action but broke as it should've on your first effort?
The next day my weak line broke at 1000 ft...
- As it should've? So why aren't you specifying this time? Can we take this to mean that it broke as it shouldn't have? And why would that have happened? You failed to tie it properly that time?

- You're down to fifty percent now.
...but I turned downwind and climbed out from 200 ft or so. I flew from central Michigan to Canada 130 miles away.
Wow. You can get up from two hundred feet and fly 130 flatland miles into another country. But you can't successfully complete a totally normal conditions tow at a rate better than fifty percent.
The first comp I flew for UP was out of Hobbs, NM. The tow system was a truck driving down a runway with a payout winch.
How'd that work out for Eric Aasletten on 1990/07/05 - the first day of the first Hobbs comp - when his Birrenator...

Image

...kicked in to safely terminate the tow as he launched into a dust devil?
As some of us know...
Oh good. As SOME of us know. A great many of us know that installing a second weak link on the other end of the bridle doubles the tow pressure required for blowing off. Name something in hang gliding that some of us DON'T know.
...the critical part is the pilot release off the bed of the truck.
It wasn't for Eric.
I hate the initial release. It is like a high wind 4 wire man launch off a cliff.
Fuckin' moron...

- You get to pick the optimal instant to execute.

- The airflow is ALWAYS gonna be glassy smooth.

- If you feel like it you can keep the bar stuffed and lift off as gradually as you please.

- I never had the slightest problem with a high wind four wire man launch off a cliff. And it tends to be the light switchy stuff that gets people totaled in cliff, slope environments.
I called it "shotgun launch".
Is it anything like the...

http://www.hanggliding.org/viewtopic.php?t=14230
pro tow set-up
Jim Rooney - 2009/11/10 17:19:54 UTC

It doesn't sound like a problem at first... more speed is good right? As with all things, yes but .... "to a point". See what happens behind a 914 if you use 582 technique is this....

You accelerate very rapidly of course and gain a lot of speed. I call it leaving the cart at Mach 5.
...Mach 5 takeoffs we used to have behind 914s before the Standard Aerotow Weak Link and Jim Keen-Intellect Rooney totally and permanently vanished from the sport?
"Ka Bam!"
Yeah... Sure...
There are so many things you have to pay attention to in truck towing besides keeping the wings level.
- There'd hafta be - seeing as how you accelerate to launch speed with your wings bolted down level.
- So how come you're not naming - or even hinting at - a single one of them?
I was first to the 100 mile goal north to Texas.
You can't fly from Hobbs - or anywhere else in New Mexico - "NORTH" into Texas.
The next pilot landed 45 mines later. Because we were timed from when we got off tow, I was not the fastest to goal.
The only thing I hate more than payout winch towing is...
http://www.hanggliding.org/viewtopic.php?t=27415
Friday the 19th with Hawks & Friends!
NMERider - 2012/10/24 21:47:05 UTC

I have to say that landing on the wheels is so much fun it's not funny.
...LANDING on wheels? Stands to reason - given your sentiments about the other end of the flight.
...added maneuver of step towing. This is were the tow vehicle has to turn around while the pilot is on tow. The purpose is to get more height on a short runway.
That's why they invented aero.
You watch the tow vehicle make the 180 degree turn as the line starts to go slack. During the slack time the pilot on tow continues in the opposite direct of the vehicle to minimize the line slack. When the slack is starting to be taken up by the tow vehicle, the pilot now turns 180 degrees and in the new direction of the tow vehicle.
I never did vehicle step. But I'd have more than welcomed the opportunity and experience.
Still there is a strong tug...
Like a 914 Dragonfly? Discounting their chintzy tow mast anyway?
...and off we go together.
- Yeah, I can see how you'd really hate it.

- So I guess when you properly tie your weak link it knows that it's not supposed to break in these circumstances - just at the beginning of a foot launch when everything's going along fine.

- How is it possible to note a "STRONG TUG" at altitude in which the focal point of your safe towing system obviously holds just fine and argue for a weak link that will break before you can get into too much trouble / "as it should" on launch?
John Heiney and I were contacted to demonstrate the air pressure ballistic rocket to deploy an emergency parachute for a TV show.
Ya know what I'd like to see any of you motherfuckers - 'specially the ones who really know towing - get contacted to demonstrate on video? An induced low level lockout in which the Standard Aerotow Weak Link succeeds AS IT SHOULD to keep someone from getting his fuckin' neck broken. Something from Davis Dead-On Straub, Ryan Instant-Hands-Free-Release Voight...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=2871
speed link
Jim Rooney - 2007/12/13 18:07:02 UTC

Pics or it didn't happen pal.
...Jim Keen-Intellect Rooney.
The United States Hang Gliding and Paragliding Association, Inc. - 2016/10/22
Standard Operating Procedure
12. Rating System
02. Pilot Proficiency System
11. Hang Gliding Special Skill Endorsements
-A. Special Skills attainable by Novice
05. Aerotow

-f. The candidate must also demonstrate the ability to properly react to a weak link/tow rope break simulation with a tandem rated pilot, initiated by the tandem pilot at altitude, but at a lower than normal release altitude. Such demonstrations should be made in smooth air.
Wish I'd thought of that one a dozen years ago.
We had to use step towing with 2-3 turns.
Really amazing that your properly tied weak link permitted you to get up that high.
I also hate coming down under half open canopy...
So the deployment went really great, huh?
...with a flying glider driving downward way faster than the FAA minimum descent rate of 15 ft a second.
But still well in compliance with respect to the FAA maximum descent rate of 45 feet per second.
"Ka Slam!"
Hope they got some quality footage so you didn't hafta do a second demo to document just how great this stuff functions in staged circumstances.

Fuckin' Infallible Weak Link scam is the biggest embarrassment these idiot sports - hang and para - have ever had to deal with. Looks like now to get a chance at hearing any reference to one ya gotta look at experiences from well over a quarter century back. Let's see just how long it takes for somebody to post anything else relevant. Willing to settle for a "line break".
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<BS>
Posts: 419
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Re: Weak links

Post by <BS> »

Image
- Obvious use of a Tad-O-Link in the above launch. Either that or it was tied improperly such that additional strength was imparted to the fishing line. Any comment anyone?
While this may look like too much trouble, if memory serves, there were no injuries. That's one clever link.
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Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

I stand corrected. It must have been an extremely properly tied weak link. I think we'd all do well to review Dr. Trisa Tilletti's seminal article on the issue in the 2012/06 magazine edition.

Also...
Donnell Hewett - 1982/09

In addition to the above mentioned roll and yaw tendancies, there is some sideways force on the pilot due to the body line. This is illustrated below:

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As can be seen, this sideways force tends to pull the pilot over to the correct side to make the glider turn naturally in the proper direction.
http://www.youtube.com/watch?v=uvhzoVC1UqM
Simple Progression for Teaching Hang Gliding
Ryan Voight - 2015/02/22

As with all hang gliding, it's important to encourage a light touch.

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If you teach them how to pull the glider with the harness they'll learn to steer the glider through weight shift simply by running toward their target.
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See how well the Center Of Mass / autocorrecting Hewett Bridle effect kicks in?
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http://www.hanggliding.org/viewtopic.php?t=36636
What is it?
Mike Bomstad - 2019/11/12 15:41:50 UTC
Butch Peachy - 2019/11/09 02:28:49 UTC

As some of us know, the critical part is the pilot release off the bed of the truck. I hate the initial release. It is like a high wind 4 wire man launch off a cliff. I called it "shotgun launch".
Sounds like the nose angle was too high, and possibly to much speed.

Should be like this Image

http://vimeo.com/32743840

Go to Cruise
Sounds like the nose angle was too high, and possibly to much speed.
- Good job getting "too" right half the time.

- Bullshit. Nobody sets the nose too high and/or comes off with too much speed on platform. He says it's like a high wind four wire man launch off a cliff. It is. It's supposed to be. Both of those are brain-dead easy.
Should be like...
- It was. The guy's a moron.

- Any comment on his weak link bullshit?

http://ozreport.com/forum/viewtopic.php?t=26134
Whipstall almost tumble
Mike Bomstad - 2011/12/26 08:33:15 UTC

Well, how about a weak link......
Just kidding.

- That's a damn good video. Probably need to do another stills project.

AT - ideally - was THE way to do hang gliding. But in reality we let a bunch of dickheaded power drivers come in and take control of the sport. With platform your driver is pretty much always another glider or glider friendly person - and the concern is entirely about getting the glider up safely and efficiently. Constant tension and the fuckin' Infallible Weak Link tends not to factor into the equation.

And the launches are so hard to fuck up that I'm on the brink of saying go ahead and fly with your easily reachable three-string if you want.

Pity that we don't/can't have the long straight empty roads-minus-powerlines where we need them to make this really viable. (And accessible airport runways tend not to be long enough.)
2019/11/09 02:28:49 UTC
That's Mike End-Of-Story Bomstad's actual time stamp format preference. Interesting to see this bozo getting, doing, saying something right every now and then.

One landing in the video - 03:00. Smooth air, fair bit o' headwind, short gentle run-out.

http://www.hanggliding.org/viewtopic.php?t=26854
Skids versus wheels
Andrew Stakhov - 2012/08/11 13:52:35 UTC

So I just came back from flying in Austria (awesome place btw). Stark difference I noticed is a large chunk of pilots choose to fly with skids instead of wheels. Conversations I had with pilots they say they actually work better in certain situations as they don't get plugged up like smaller wheels. Even larger heavier Atosses were all flying with skids. I was curious why they consistently chose to land on skids on those expensive machines and they were saying that it's just not worth the risk of a mistimed flare or wing hitting the ground... And those are all carbon frames etc.
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Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Complement to: / Continuation of:
http://www.kitestrings.org/post11826.html#p11826

http://www.youtube.com/watch?v=nVeI7oiwRwM
Wills Wing Demo Days at Cowboy Up
Thermal Cowboy (Tyson Taylor) - 2016/04/12

Some footage from April and some of the 2016 Cowboy Up Wills Wing Demo Days
mirageg4
Looks like you handled the weak link break like a pro.
Tyson Taylor
Thanks Mark, I couldn't remember if I pulled in or not when it broke. THat was my first WL break and I guess all my training took over
http://ushawks.org/forum/viewtopic.php?f=2&t=3601
angle of attack
Craig Muhonen - 2019/11/15 17:36:39 UTC

Here is a statement to me at age 13, by my father, who was teaching me how airplanes worked, and why they worked. He said "a nose heavy airplane is hard to fly, but a tail heavy airplane....flies once". He taught me all about 'trim', and angle of attack. Later on when I went for my rating as a pilot, my instructors had practiced with me over and over, about these things. Although I was a bit nervous when I 'soloed' and flew my first cross country, I knew that my step by step training would serve me well, so I "stepped" myself into the atmosphere. Flying "wings level" and "turning" at some altitude is remarkably "easy", but close to the ground, getting ready to land, and take off, brought AOA and trim to the forefront.
http://ushawks.org/forum/viewtopic.php?f=27&t=2434
Rethinking towing
Bob Kuczewski - 2019/11/18 11:04:16 UTC

This video from the Houston Club shows a weak link break during an aero tow:

http://www.youtube.com/watch?v=nVeI7oiwRwM


The tow starts at about one minute and 30 seconds (1:30) into the video. The weak link break isn't easily visible, but happens shortly after 2 minutes into the video.

The glider's mild response to the weak link break reminds me of the static tow weak link break demonstrated in one of Bill's videos. It seems obvious that the glider's undesired response to a weak link break will increase with the strength of the weak link.
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Comments on the suspension - now that we have a clear view of it.

- Spreader's in the right place - but let's not go nuts 'cause in this configuration it's not like there's the usual option to fuck it up to the maximum extent possible - à la Chris Valley.

- Total moronic, ugly, sloppy, draggy crap. This asshole's never gonna need:
-- an upper bridle attachment point to trim his glider back into certified configuration
-- a release that doesn't stink on ice
-- the ability to stay on tow in any emergency situation that calls for it (the vast majority of them)
-- the extra performance, glide range he'd have if he hadn't butchered it
But he's gotta have a fuckin' backup loop in case the thirty G primary fails and the keel remains intact.

- Fuck Wills Wing for pandering to these morons. Introduce one element of stupidity and it's a base of operation for undermining the integrity of the entire sport. And those assholes are reaping the benefits of decades of this bullshit now.

- P.S. Good luck on the Board getting things back on track, Steve. (And thanks bigtime for all your past support for Yours Truly.)

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Safety of the towing operation (which totally sucked to begin with) abruptly increases between this frame and the next.

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When you're in Final Cut going frame by frame (or flipping through the individual images in Photoshop) you can see the distinct jolt.

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And now that we've blown at least fifty bucks worth of resources just on the tow itself we get to enjoy the safety increase benefits of an extra landing and - time permitting - launch. (Don't worry... Below a thousand feet it's free and you get to cut back in at the head of the launch line. (Ever wonder why neither you nor your driver had any inclination to terminate the tow before your precision fishing line and Pilot In Command made the call?)

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And now another bar stuff to safely recover from the increase in the safety of the towing operation. (Anybody wonder how much safer the Dragonfly's getting with all these extra launch and landing cycles?)

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Go back up to 094-20529-H and compare horizons.

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Bye-bye Dragonfly. It's sure been fun. Happy landing.

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Sure you're not cutting things too close waiting until this point to go upright to the control tubes?

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

Re: Weak links

Post by Tad Eareckson »

http://www.youtube.com/watch?v=nVeI7oiwRwM
Wills Wing Demo Days at Cowboy Up
Thermal Cowboy (Tyson Taylor) - 2016/04/12

Some footage from April and some of the 2016 Cowboy Up Wills Wing Demo Days
Think you Houston/Cowboy/Wills guys could manage to move the sport backwards a bit faster than you're doing now?
mirageg4

Looks like you handled the weak link break like a pro.
- He IS a pro. Just look at the bridle he isn't using.

- What? For an INCREASE in the safety of the towing operation you need to call on professional level skills? Sounds to me like you're trying to make more of this crappy argument that being on tow is somehow safer than being off tow. And I've always heard that a Standard Aerotow Weak Link success is just an inconvenience at the very worst. You can handle an inconvenience like a pro?

- What do you figure Tyson, who isn't a pro and just benefitted from his first Standard Aerotow Weak Link success, was doing better than Zack Marzec, who IS - sorry, make that WAS - an actual pro? Maybe you could describe the requisite skills and training exercises involved. All I'm seeing him doing is stuffing the bar and waiting for the fuckin' glider to start flying again.
Tyson

Thanks Mark, I couldn't remember if I pulled in or not when it broke.
- You pulled in. Try watching the fuckin' video.
- Why did it break? No, wait. It's supposed to break before you can get into too much trouble. Forget I asked such a stupid question.
THat was my first WL break and I guess all my training took over
Fantastic job Bart and Tiki. Keep up the great work.

http://ushawks.org/forum/viewtopic.php?f=2&t=3601
angle of attack
Craig Muhonen - 2019/11/15 17:36:39 UTC

Here is a statement to me at age 13, by my father, who was teaching me how airplanes worked, and why they worked. He said "a nose heavy airplane is hard to fly, but a tail heavy airplane....flies once". He taught me all about 'trim', and angle of attack. Later on when I went for my rating as a pilot, my instructors had practiced with me over and over, about these things. Although I was a bit nervous when I 'soloed' and flew my first cross country, I knew that my step by step training would serve me well, so I "stepped" myself into the atmosphere. Flying "wings level" and "turning" at some altitude is remarkably "easy", but close to the ground, getting ready to land, and take off, brought AOA and trim to the forefront.
Yeah, a pro toad hang glider is a tail heavy airplane. Every single goddam one of them is a fatality waiting for a well placed thermal blast to happen - somewhat regardless of altitude. The instant you're Rooney Link pops you cease being tail heavy but by the time that happens you may already be too nose high for any chance of survival.

http://ushawks.org/forum/viewtopic.php?f=27&t=2434
Rethinking towing
Bob Kuczewski - 2019/11/18 11:04:16 UTC

This video from the Houston Club shows a weak link break during an aero tow:

http://www.youtube.com/watch?v=nVeI7oiwRwM
A totally illegal tow with the glider in a decertified configuration and using a weak link on the verge of or under minimum legal strength depending on the glider's max certified flying weight.
The tow starts at about one minute and 30 seconds (1:30) into the video.
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The weak link break isn't easily visible...
And whenever something in hang gliding isn't accomplished easily one shouldn't bother pursuing it further.
...but happens shortly after 2 minutes into the video.
Right after here:

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and before the next frame - running 30 fps.

So WHY does it happen? Is the tow out of control any more than at any previous point? Why didn't it happen:

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Is that how we're supposed to be flying? Using a piece of fishing line to override the decisions of both front and back end pilots to continue the tow whenever it feels like it?
The glider's mild response to the weak link break...
Neither the pilot nor the single respondent to the video considered the glider's response to have been so fucking mild. See above. Here's the inconvenience progression:

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Precisely four seconds between the beginning of the undesired event and recovery from it. That is NOT a MILD response - from either the glider or the asshole trying to fly it. When those happen low in mechanical and/or thermal turbulence gliders get crashed and guys trying to be pilots get injured and killed. There's a reason u$hPa specifies the teaching of these fake inconvenience response drills in smooth air way the fuck up with the tandem instructor executing the pop at a time of his choosing.

And if you care to argue that that's a mild event then you show me a four second video sequence from a free flight in which the glider's getting kicked around to that degree - preferably while low on final.
...reminds me of the static tow weak link break demonstrated in one of Bill's videos.
This one?

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No, wait. That's not one of Bill's videos. So we should just ignore it. Sorry.
It seems obvious...
- And if Emperor Bob tells you anything SEEMS OBVIOUS you should just totally disregard basic Newtonian physics, all your personal experiences, decades worth of fatality reports going back to the beginning of time.

- Does it seem obvious that he should've been using a two point bridle?

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How come we see all these constant control frame gymnastics on the way up but on the way down...

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...everything looks totally sane until he goes upright to the control tubes?
...that the glider's undesired response to a weak link break...
Oh! So you're SAYING that this is an UNDESIRED response! See above about that crappy argument. (I remember the days when you could and would be immediately lynched for making a statement like that. Feel free to thank me at your leisure.)
...will increase with the strength of the weak link.
So then it seems obvious to me that we should be using weak links half the strength of this one. (Looks like this:

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on Amber's bridle. (Looks a bit short to me. Anybody else feel the same way?)). Granted, we'd get twice the number of undesired breaks but the effects would only be half as undesirable. (Right...

http://ozreport.com/forum/viewtopic.php?t=31052
Poll on weaklinks
Jim Rooney - 2013/03/05 01:32:20 UTC

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

Here's another thought...
Dr. Trisa Tilletti - 2012/06

Trisa 1: 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.

Trisa 2: 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.
Use a release that doesn't stink on ice to terminate the tow upon the decision of one of the pilots - preferably the one on the back end - and use the fuckin' weak link to protect from structural overload - the way they've ALWAYS done it in sailplaning and have NEVER done it (on any appreciable scale) in hang and paragliding.

Wanna do obvious? AT weak link strengths started going way the fuck up to Tad-O-Link level after Pete Lehmann sanded his knee down to the bone at Zapata 2011/08/11 and way more so after Zack Marzec's 2013/02/02 fatal Quest inconvenience tumble. Cite one single Tad-O-Link skinned knee incident in the years since from anywhere on the planet. On show me a video.

We aerotow 'cause it's the most effective and efficient and lowest cost means of getting lotsa gliders into the air in prime thermal conditions all the XC comps and world distance record flights are launched AT. There's some mechanical turbulence going on in this one but its just fairly high wind sled conditions. And you can't predict what will happen as a consequence of a Standard Aerotow Weak Link inconvenience in thermal conditions. It can be and usually is just an extremely expensive pain in the ass. But it can be permanently life altering or fatal. And it's a much greater threat than a low level thermal induced lockout is.

If you're not scared about a third shitless every time you AT launch in good soarable conditions you have no business doing it. Ditto for comparable mountain launches. And if you've gotta fly behind some total fucking douchebag like Jim Keen-Intellect Rooney and/or under equipment standards set by Davis Dead-On Straub you're a far superior pilot if you stay home and play checkers. Ask Mike Haas or Jeff Bohl if you don't believe me.

I haven't hooked into a glider for over eleven years now and I'm still a better pilot than any of those CHGA, Ridgely, Flight Park Mafia douchebags can ever dream of being.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Jump to next post:
http://www.kitestrings.org/post11922.html#p11922

This video:

http://www.youtube.com/watch?v=bTa6XL16i0U
SCFR Day 2 Highlights
LAGlide - 2011/09/20
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is a majorly important historical document. (And we're real lucky to have it on Jonathan quality video.)

- Two of Jonathan's pro toad topless launches at the 2011 Santa Cruz Flats Race, Day Two, 2011/09/19.

-- First one illustrates the safety of the towing operation being increased with the topless rock steady in perfect position and the air doing nothing at the cost of a couple inches of 130 pound Greenspot precision fishing line and a bit of inconvenience - for Jonathan, the Dragonfly, two or three totally useless launch crewmen, cart retrieval, all the motherfuckers waiting in line, four or five tugs... The real world cost of this precision fishing line determined increase in the safety of the towing operation at this event is several thousand bucks if it's a nickel.

-- Second one the focal point of Davis's safe towing system and Pilot In Command of Jonathan's and his driver's tow deems it safe enough to continue all the way up to wave-off.

- This is desert and it's dry. All the relevant surfaces - both launches, both landings - are either dust or not enough pavement to matter. We can SEE *ALL* of the relevant air. Wind direction and strength and tug propwash. We can tell that this Dragonfly is a 582 'cause it's just dust - no rocks. It's of course way easier to see what's going on - and isn't - with the air, propwash watching the video sequences but you can see it in the stills. And better if you load them into Photoshop or sumpin' and flip through the sequences. (And if anybody wants the MP4 then let me know.)

- In 004-01819 through 009-02306 on the right side of the frames we're seeing two launch dolly retrieval carts and their drivers in standby position.

- Appropriate easily reachable pro toad release.

- We've never heard a single syllable about this Standard Aerotow Weak Link being in less than pristine condition so it's an extremely safe assumption that it wasn't.

- This weak link is seeing fifteen percent less load on Jonathan's one point bridle than it would've on a two point. And no two point bridle passes the appropriateness muster under Davis comp rules (which at this point likely permit inappropriate weak links with finished lengths of 1.5 inches or less).

- We have Bill Cummings - out west near exactly three hundred crowflight miles from home in Las Cruces. Important early Hewett Skyting Cult member and one of the surviving world's leading authorities on the Hewett Infallible Weak Link.

- This is 39 days after the Zapata World Record Encampment when the Standard Davis Weak Link quickly coincidentally increased the safety of the towing operation six times in row in light morning conditions (2011/08/11) before Russell Brown decided we'd all be happy with the double strength Tad-O-Link - particularly Pete Lehmann whose inconvenience included having his left knee sanded down to the bone.

- This is exactly the same tow configuration which will tumble and kill tandem aerotow instructor Zack Marzec at Quest one year, four months, two weeks later. The only two things missing were the monster thermal breaking off shortly into the tow and the decisions by both pilots to continue the tow into it. Zack had at least 1.5 zillion times as much AT experience as Jonathan, it's a good bet that Mark Frutiger was at least up to par with this unidentified, there's never been the least criticism of the decision to continue the tow by anyone in the mainstream (what could possibly be the point since none of us will ever have the slightest idea of what happened), there was a very heavy Quest influence at this event, it's an excellent bet that Jonathan would've ended up at least as dead as Zack did.

- Jonathan references his "AT instructor" who's present at the event and observing the first launch. So it's a virtual no-brainer that Jonathan’s never done AT before a practice day on Saturday and can count his launches on the fingers of one hand as this Day Two round gets underway.

- Ignoring the total crap excuse for an equipment configuration and consequential issues somebody show me an AT relevant frame in which Jonathan's performance is a hair south of perfection.

- Note that in all frames in which Jonathan's on tow the tug is either dead on the horizon or off to a degree not worthy of mention. At 090-10608 Jonathan's making the easy reach to his easily reachable release and has popped off between 091-10625 and 092-10627. (Probably just after wave-off with the tug throttled back.)

- On neither of Jonathan's landings - the inconvenience response and the planned and set up XC - does he stop with a perfectly timed and executed landing flare.

-- On the inconvenience response he runs out of steam and the starboard control frame corner digs in. (The SCFR Safety Committee doesn't recognize the least safety value of wheels or skids. As long as one takes off with an appropriate weak link with a finished length of 1.5 inches or less what more could one possibly need? Well, a helmet and parachute maybe.) Keeps the nose up anyway.

-- At the conclusion of the XC he slides in on his knees, experiences the slowest and lightest of beaks

-- Zero damage to glider and self on either.

-- Name one instructor who has ever taught or advised Jonathan's XC landing execution under any circumstances. (Although if you listen to Steve Pearson - who's present and competing at this one...) Also name one instructor who has ever allowed himself to be filmed landing in real world circumstances.

- We can see the shadow of the camera that recorded this world treasure in several frames when Jonathan's back on the ground at the conclusion of Flight 2 starting at 146-21716.

I've had this collection sitting at 47 shots for a good many years then two days ago I did things pretty right and went up to 129. Fairly confident now it will stay that way.

2020/06/02 - Nope. Needed to add another nine.
2020/06/03 - Nope again. Needed to add another thirteen on top of that. (Total nightmare to re-catalog stuff added to the middle.)

Also fairly confident it'll be a really cold day in Hell before we see another Davis Link induced increase in the safety of a comp towing operation. Think Jeff Bohl, Tad-O-Link, underpowered tug compromised, fatal lockout, just how much discussion we heard about AT weak links as the smoke cleared.

Realized the necessity of the expansion and this first formal stills project for this video (thought I'd done one before and would have had to amend it) as a consequence of the 2020/05/25 marathon phone conversation with Bob.

Major bitch. Had to go through the forum's entire archive updating ID codes, standardizing Flickr URLs and image addresses. Also did a lot of work patching and upgrading posts (dead images, corrections, standardized formatting...). Creeping up on twelve thousand posts now.

Davis Link safety increasing inconvenience occurs between 024-02818 and 025-02819. And that particular sequence was the primary impetus for this current upgrade.

Launch is 32°52'54.67" N 111°51'14.09" W - Runway 30. Landing is 32°41'02.50" N 111°26'59.25" W - about 27.2 miles ESE from getting airborne (partway to Jacksonville along I-10).

The two mountains we see as Jonathan's cruising over the Interstate towards what will be his landing are Newman and Picacho Peaks, 4506 and 3374 feet MSL, left and right respectively. (Launch is 1342, landing is 1690.)

Jonathan's comment (posted on Kite Strings) on the first effort:
NMERider - 2014/11/20 20:02:40 UTC

Launched in a 3mph tailwind and stayed on the cart until I had more than enough airspeed to execute a safe landing in a tow failure.
The weak link broke and I made a smooth transition to the uprights in order to set up a decent landing.
Could have simply flared hard and ran in the slight tailwind. Got lazy and tried a right turn to land crosswind.
Ran out of airspeed and mushed into the ground sliding sideways. Doh! :oops: :lol:
My AT instructor told me I would have been fine just landing in the slight tailwind.
Pilots don't always stay on the cart long enough for situations like this. The cart wheels are good as long as the casters line up.
It's better to hold on to the cart until there's more than enough airspeed to set up a safe landing and then release the cart.
Yes, weak links can be problematic and pilots must be ready for what can and will go wrong.
---
2020/07/11 22:15:00 UTC - From Jonathan on The Jack Show regarding these flights and this comp:

http://www.hanggliding.org/viewtopic.php?t=23199
Santa Cruz Flats Race Day 1 & 2 - Video
NMERider - 2011/09/20 13:23:41 UTC

The highlight of Day 2 was meeting Org member, Bill Cummings in person and having him assist me a whole bunch on the flight line. Unfortunately I could not chat on radio during the flight due to the stress and distraction to my teammates.

Bill has also stepped up to become my first sponsor! I need to start a sponsor page or such and begin passing the hat so I can continue to fly interesting routes and keep up the editing.

So, I broke my first weak link while towing downwind. I had a clean second launch but made a judgment error ten miles or so into the flight and only went less than half the course. I think this will drop me lower from 22/37 flex wing pilots. Live and learn.

In order to stretch my final glide before I hit a bailout, I surfed the 10 freeway for nearly two miles.
NMERider - 2011/09/20 14:04:57 UTC

Lack of sleep; lack of ground streamers; turbulence; and fatigue from difficult (for me) flying. On the weak break, many pilots would have piled in. The skid was the correct way to handle it. My relaxed, pre-comp landings have been fine. I haven't had to time to explain how my left knee went out during flight on Day 1, and I could not stand when I came into land so it buckled.
NMERider - 2011/09/20 16:31:28 UTC

I have only had four solo aero tows in my life and three were in the comp and one the day before. I'm lucky Jamie and Mitch have allowed me to fly. If not for the excellent Scooter Tow instruction from Mark Knight and Bill Bennett followed by the outstanding instruction from Mitch Shipley and the Quest crew, I would not have had been able to fly in the meet.

Also, if not for the thorough instruction of Mitch, weak link break at ten feet may have had an unpleasant outcome. Don't forget that was a downwind launch folks!

Maybe, after today Jamie will let me launch with the Covert. Conditions are so weak that the extra drag of the cocoon is not a handicap. My being in 26th place is entirely due to lack of experience and decision making skills. My equipment and flying skills are on par with 90% of the field.

For my first race comp, I have no complaints at all. I will pay closer attention to my landings, and if I have to, I will moonwalk them unless I'm over an unsafe surface.
---
And Jonathan... If you'd like to participate in the discussion on these two flights I'd be super delighted.

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

Re: Weak links

Post by Tad Eareckson »

This crap:

http://www.ushawks.org/forum/viewtopic.php?f=2&t=1563
Platform Launching (PL) Draft suggestions needed
Bob Kuczewski - 2014/06/06 17:50:48 UTC

As another suggestion, I think the notions of balance and pilot choice should be introduced at some point. The curve of injuries as a function of weak link strength probably looks something like this:

Image

That means there's danger on either end ... and even at the lowest (best) possible point!!

However, the shape of that curve for any particular pilot is based on their choice of equipment, conditions, and their own pilot skill. A pilot with good skills at recovering from weak link breaks (as Bill mentioned above) will be operating with a curve that's much lower (less chance of injury) on the left side than a pilot with poor skills at recovering from weak link breaks. Similarly, a pilot using a good quality release will be operating with a curve that's lower on the right side than a pilot using a poor release.

In the end, I think the best weak link strength will be based on the combination of equipment, conditions, and pilot skill. So one of the goals of this chapter should be to show the full range of those issues so the individual pilot can be educated as to how to weigh them in making their own choice of weak link strength. It's important to remember that the safest weak link strength may differ between two pilots even if they have the same weight, equipment, and conditions. Their skills matter, and I think that is very well said in Bill's post.

Great topic and discussions Bill, Sam, Mike, and Charlie!!!
is what got me thinking and inspired be to spend a few hundred hours (so far) massively upgrading the stills collection off of Jonathan's inadvertent gem of a smoking gun video. I don't know if you just plagiarized Hewett's lunatic crap or would've pulled it out of your own ass if you'd been raised in a vacuum.

Donnell didn't really recognize the left side of the graph. There was absolutely NOTHING bad that could happen to you in free flight subsequent to coming off a tow - as long as your Infallible Weak Link was 1.0 Gs or under. Go up from there and you were still good up to 2.0 if you were a very experienced aerobatic pilot. So for Donnell we'll just use 1.0 for what-bad-thing-could-possibly-happen and the high right end for 2.0 / only Bo-Hagewood-would-come-out-smelling-like-a-rose.

So then, Bob, why is the sailplane graph just an arrow-straight line from low left to high right? The Maximum Certified Operating Weight of your sailplane is X, its manufacturer specifies a Tost weak link of 1.4X. They don't give a rat's ass about your skill level, whether you weigh a hundred pounds and are going up solo in a two-seater or are loading their plane to the max, whether it's an early morning sled or nuclear Owens midafternoon thermal. 1.4 times the Max Certified Operating Weight and it will:
- never blow in a situation that hasn't gone tits up
- safely blow before your plane can be broken but whatever happens next is your problem

So you tell me what's so inherently different between conventional sailplanes and hang gliders towed in HGMA certified configuration (hook-in weight, prone, both hands on the control bar at all times, trimmed for tow in accordance with what Rob Kells has specified for Wills Wing gliders) that there's total zilch correlation between the sailplane graph and the Kuczewski graph?

Also... It's my understanding that you have very little experience in hang glider towing so can you find me a graph similar to yours from Wallaby, Quest, Lockout, Currituck, Ridgely, Trisa, Whitewater, Cowboy Up.

Never mind about the last one actually...

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.
But maybe you could do a graph for us.

I'll tell ya sumpin' else about the sailplane graph...
Dr. Trisa Tilletti - 2012/06

Trisa 1: 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.

Trisa 2: 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.
So that means that in all those experiences and observations the tension was never getting up to 1.4 Gs. They could've all been 3.0 G weak links and there'd have been zero difference. So if you're forced with a gun to your head to go high or low...
Tost Flugzeuggerätebau

We recommend that the weak link insert are replaced after 200 starts: AN INSERT EXCHANGED IN TIME IS ALWAYS SAFER AND CHEAPER THAN AN ABORTED LAUNCH.
...which way? Which way do the people in the sport who actually fly these things...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=2467
weak links
Jim Rooney - 2007/07/22 22:30:28 UTC

I've heard it a million times before from comp pilots insisting on towing with even doubled up weaklinks (some want no weaklink). I tell them the same thing I'm telling you... suck it up. You're not the only one on the line. I didn't ask to be a test pilot. I can live with your inconvenience.
...wanna go? Which way did The Industry...

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...go. And WHY? Seeing as how we had a proven system that worked with an extremely long track record. (And the Tad-O-Link now has a track record getting on to nine years now? How come we never here about it? Is it not working? Is it's track record not long enough to really say one way or the other? (I think the only report of a Tad-O-Link working we've had so for was Jeff Bohl's - 2016/05/21. And he wasn't in too much trouble until after the tow was safely terminated.))

But anyway...
Bob Kuczewski - 2014/06/08 04:14:46 UTC

My entire hang gliding towing experience consists of one tandem aero-tow at Wallaby Ranch ... where I was the passenger (thanks for the flight Malcolm). So my comments come more from an attempt to understand towing than any pretence of authority on the subject.

One of my thoughts while mulling this all over is that the severity of the glider's response to a line break must be related to the amount of tension in the line when it broke. In other words, if the tension is very close to zero before the break, then the glider's response will be very close to zero after the break. Is that generally true?

Similarly, if the tension is very high at the time of the break, then that means that the force diagram before the break shows a large force along the tow line and an equally large force opposing it. At the moment of the line break, the tow line force becomes zero, and the opposing force is converted to acceleration (actually deceleration in this case) according to Sir Newton's F=ma. So the greater the line tension at the time of the break, the greater that thrust change and subsequent deceleration will be. Is that generally true as well?

Thanks for the great discussion. It's great to see all aspects of a topic like this being explored!!
My entire hang gliding towing experience consists of one tandem aero-tow at Wallaby Ranch ... where I was the passenger (thanks for the flight Malcolm).
- Yeah Bob, pretty much everybody who participates in back end Flight Park Mafia aerotowing is a passenger.

- It's been a violation of FAA regulations since the beginning of time for passengers to go up on hang gliders. It's NOT a violation of any FAA regulation or any intelligible u$hPa SOP to be kiting a paraglider minus a "Helmet". And what are the relevant fatality stats?

- You were a fucking Hang Four. And Malcolm STILL didn't allow you to touch the control bar?
So my comments come more from an attempt to understand towing than any pretence of authority on the subject.
- Yeah, right.
- And it always helps diffuse accusations of pretentiousness when one spells pretense that way.
One of my thoughts while mulling this all over is that the severity of the glider's response to a line break must be related to the amount of tension in the line when it broke.
THIS rot is what got me fired up over this Jonathan SCFR video project.
In other words, if the tension is very close to zero before the break...
If the tension were very close to zero before the break then HOW THE FUCK DID:
- YOU MANAGE TO GET UP THERE? HELIUM?
- THE WEAK LINK MANAGE TO BREAK?

Do find us a video or two of some of these sequences - preferably stuff from Planet Earth.
...then the glider's response will be very close to zero after the break.
Since it's still parked motionless on the cart... Yeah, pretty safe bet.
Is that generally true?
Totally nailed it. Amazing, given that you have very little experience towing.
Similarly, if the tension is very high at the time of the break, then that means that the force diagram before the break shows a large force along the tow line and an equally large force opposing it.
Newton sure nailed that one, didn't he?
At the moment of the line break, the tow line force becomes zero, and the opposing force is converted to acceleration (actually deceleration in this case) according to Sir Newton's F=ma.
Yeah, it's a lot like when your engine seizes up on your Cessna. That's why you always wanna take off at minimum possible power. Either that or adhere to maintenance schedules to make sure your engine doesn't seize up on takeoff.
So the greater the line tension at the time of the break, the greater that thrust change and subsequent deceleration will be. Is that generally true as well?
Your talents are being so wasted at slope launch sites.
Thanks for the great discussion. It's great to see all aspects of a topic like this being explored!!
Yeah, hard to imagine where hang glider towing might be now without The Bob Show where free speech is so highly valued.

This is twenty times more deranged than I remembered based on a not nearly careful enough reading a little over five days shy of six years ago. I'll end this post and then get back to the Jonathan Launch One sequence which deals with the take on this at just the average level of derangement.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

One of the standard Flight Park Mafia lines on the focal point of our safe towing system - the one considerably less lunatic than Bob's but which he was obviously trying to make and what I'd thought he was making - was that the ideal AT weak link was six ounces over normal tow tension (whatever the hell that was) 'cause then you'd have to deal with minimal "RECOVERY" issues WHEN it decided to increase the safety of the towing operation while the tow was proceeding with zero problems. And this is pretty much straight out of the Hewett cult book.
Donnell Hewett - 1980/12

A properly designed weak link must be strong enough to permit a good rate of climb without breaking, and it must be weak enough to break before the glider gets out of control, stalls, or collapses. Since our glider flies level with a 50 pound pull, climbs at about 500 fpm with a 130 pound pull, and retains sufficient control to prevent stalling if a weak link breaks at 200 pounds pull, we selected that value. Of course, a pilot could deliberately produce a stalled break at 200 lbs, just as he can stall a glider in free flight. But if he is trying to limit his climb rate and the forces exceed the break limit, the glider simply drops its nose to the free flight attitude and continues flying. If the weak link breaks (or should the towline break) at less than the 200 pound value, the effect is even less dramatic and controlled flight is still present.
It's supposed to be an overload protector and never in the first several decades of hang glider towing was a weak link EVER considered an overload protector. At the beginning - even with primitive pre HGMA gliders, towing frame only - they checked everything every other tow at a minimum to make goddam sure that NOTHING would break. But it's critical for the Hewett Infallible Weak Link to succeed at a point at which the glider simply drops its nose to the free flight attitude and continues flying. And thus began the arms race which concluded with the Standard Aerotow Weak Link.

And this one's TEXTBOOK.

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Smooth as glass. If you're designing for a seamless transition it can't get any better than this.

But - fly in the ointment - there's supposed to be something going wrong for the Infallible Weak Link to have had to have worked.

We don't see the slightest wobble from turbulence. And the tug's not doing anything. (Besides, all tug drivers are superb pilots - beyond reproach for anything under any circumstances.) So that leaves...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=2467
weak links
Marc Fink - 2007/05/25 00:26:39 UTC

I suspect he'll kill me for mentioning it--but Larry Huffman has never broken a weaklink in 11 years of aerotowing. Is he lucky, beating the odds somehow, or only goes and tows in perfect calm conditions? I think not. Rather, he recognizes that safe towing is not a question of where you keep the tug or glider as an absolute priority--but that the overall safety of the tow has to do with towline pressure management. Thus, the pilot needs to anticipate what will happen to the pressure on the line and take whatever corrective action is necessary to correct a potential overbuild of pressure. It takes alot of skill to be able to respond with the right degree at the right time to prevent oscillations in tow pressures. These typically happen when transitioning spots of lift/turbulence where most likely the rising and falling of the tug and glider will be out of synch and therefore the proper input needs to be in anticipation of that lag.
...the glider pilot.

And the GoPro was the worst thing that ever happened to the Flight Park Mafia and its operatives. If Jonathan's not doing this right it can't be done right. (Pity we don't have any videos of Larry Huffman towing and the only video we have of Bo Hagewood is him in a another body cast asking for donations to replace the Florida Ridge Dragonfly he recently totaled. (That's not going real well by the way. Been stalled at $3822 since 2020/05/31.))

Birds of a feather:

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The Standard Aerotow Weak Link isn't fuzzed. Only appropriate weaklinks are permitted and an appropriate weaklink will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line placed at one end of a shoulder bridle. And these weaklinks are provided by the meet organizers in a manner approved by the meet organizers and are checked. And any use of inappropriate weaklinks require the pilot to go to the end of the launch line to change the weaklink.

Bloody well right. You certainly don't wanna have fuzzy inappropriate weaklinks succeeding six times in a row in light morning conditions and inconveniencing pilots back down on the paved runway.

Seriously folks. This WAS a single loop of 130 pound Greenspot and it WAS NOT fuzzed.

And...

http://ozreport.com/forum/viewtopic.php?t=27494
The exciting bits
Jim Rooney - 2012/05/28 11:49:58 UTC

Guys
Your questions hold the answers.

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

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

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

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

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

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

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

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

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

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

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

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

Let's give the little twat the benefit of the doubt and call this a 582. And there's a substantial right cross - let's call it NNE and no more than ten. But look at the propwash. We can see it pretty distinctly from 016-02707 through 020-02726. Most of it drifts on by the glider to the left but look how dispersed it is - high and wide. Can we imagine being able to FEEL what we're seeing?

- But Little Twat portrays this as a routine occurrence. So we shouldn't have too much trouble finding a representative video and no trouble at all finding personal accounts. Where are they? I launched through plenty of propwash dust clouds - and at Ridgely it was pretty much all 914s. And I don't recall ever having felt anything or noticing any change in wind noise.

Little Twat always pictured himself as a Top Gun fighter jock locked into the steam catapult with his F-14 afterburners blazing into the blast deflector behind him ready to go back up once again to put his life on the line to protect our liberties and way of life from the evil Tad-O-Linkers. Really disgusting the way we never expressed proper appreciation and so quickly forgot about him after the second time he was shot down over the SE slope of Coronet Peak.

Furthermore... Jonathan - with zilch previous AT experience - takes off exactly as one's supposed to. Waits on the cart until his wing has speed, trims, clears the keel cradle then allows the hold-downs to slip free of his grasps. There's zilch going on with drag/tension increase at this stage. And if there is then somebody please explain to me why the focal point of his safe towing system increases the safety of the towing operation at:

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and not:

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Boy do I love Go Pro, YouTube, Final Cut, Photoshop. Think how much more fun I could've had ripping that little shit to shreds on the Capitol rag back in 2008 with this kind of power at my fingertips. Oh well, better postmortem than never. And it's a no-brainer that the more effective I'd been the quicker those motherfuckers would've cut my wire.
User avatar
Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

First off...

As I started composing this one I revisited:

http://www.youtube.com/watch?v=fnrh9-pOiq4
Hang Glider Lock-Out!
MorphFX - 2011/03/20
A hang glider pilot learning to aerotow starts a mild PIO that leads into a lock-out.
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I reviewed my archived copy, started noticing stuff on which I hadn't picked up before, checked the Kite Strings stills archive at:

http://www.kitestrings.org/post6995.html#p6995

It was 23 frames. And now after several days of hell it's one shot shy of five times that. DO check it out. Major smoking gun gold mine. It pretty definitively drives a stake through the heart of decades of the AT industry snake oil of a Standard Aerotow Weak Link being able to work any better than a tinker's cuss in the event of a low level lateral lockout. (And the LAST thing we want it doing is working in a vertical.) It's about the best documentation we're likely to ever have and I have little doubt that BHPA had it taken down for that reason.

We know that the top of the BHPA AT weak link range just barely noses up into the bottom of the FAA legal range and we watch that glider locking out and getting - for the purpose of the exercise - totally vaporized with their Infallible Weak Link doing just fine. Ditto for the tug. I doubt that asshole is ever even aware that anything out of the ordinary is going on behind him. (I have the last frame he's on and the first frame - a thirtieth of a second later - that he's off. Christmas in June.)

And there's never been the slightest dispute about anything in the video or the reports we had at the time.
---
Donnell Hewett - 1980/12

A properly designed weak link must be strong enough to permit a good rate of climb without breaking, and it must be weak enough to break before the glider gets out of control, stalls, or collapses. Since our glider flies level with a 50 pound pull, climbs at about 500 fpm with a 130 pound pull, and retains sufficient control to prevent stalling if a weak link breaks at 200 pounds pull, we selected that value. Of course, a pilot could deliberately produce a stalled break at 200 lbs, just as he can stall a glider in free flight. But if he is trying to limit his climb rate and the forces exceed the break limit, the glider simply drops its nose to the free flight attitude and continues flying. If the weak link breaks (or should the towline break) at less than the 200 pound value, the effect is even less dramatic and controlled flight is still present.
There it is. Ground Zero. Pure unadulterated lunacy. It will break before the glider gets out of control - just as long as you have the glider under full control at the time. If you don't the glider will stall. If you do the glider will recover (from the dangerous under control attitude at which you were flying). He doesn't even say anything about LOCKOUTS. Am I the only one out there who was thinking that he was? Primarily? 'Cause we're all scared shitless of lockouts and not scared in the least by...

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...steep climbs? The reason he doesn't say anything about lockouts is 'cause his Center Of Mass Skyting bridle...
Donnell Hewett - 1982/09

In addition to the above mentioned roll and yaw tendancies, there is some sideways force on the pilot due to the body line. This is illustrated below:

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As can be seen, this sideways force tends to pull the pilot over to the correct side to make the glider turn naturally in the proper direction.
...took that issue totally out of the equation. The more sideways you get the more effective the Skyting bridle is at pulling you back to center. (Not working effectively enough? Radio your driver and tell him to hit the gas.

Back in the day, even in that era of frame towing the inconvenience stall was still the killer that scared people most shitless.

http://www.ushawks.org/forum/viewtopic.php?f=2&t=1563
Platform Launching (PL) Draft suggestions needed
Bob Kuczewski - 2014/06/06 17:50:48 UTC

As another suggestion, I think the notions of balance and pilot choice should be introduced at some point. The curve of injuries as a function of weak link strength probably looks something like this:

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That means there's danger on either end ... and even at the lowest (best) possible point!!

However, the shape of that curve for any particular pilot is based on their choice of equipment, conditions, and their own pilot skill. A pilot with good skills at recovering from weak link breaks (as Bill mentioned above) will be operating with a curve that's much lower (less chance of injury) on the left side than a pilot with poor skills at recovering from weak link breaks. Similarly, a pilot using a good quality release will be operating with a curve that's lower on the right side than a pilot using a poor release.

In the end, I think the best weak link strength will be based on the combination of equipment, conditions, and pilot skill. So one of the goals of this chapter should be to show the full range of those issues so the individual pilot can be educated as to how to weigh them in making their own choice of weak link strength. It's important to remember that the safest weak link strength may differ between two pilots even if they have the same weight, equipment, and conditions. Their skills matter, and I think that is very well said in Bill's post.

Great topic and discussions Bill, Sam, Mike, and Charlie!!!
Sure Bob.

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This guy is STILL on tow, his weak link is at the absolute bottom of the US legal range (and top of the UK legal range (which has no bottom)), he's in the process of swatting his Koch release paddle, he'll be off in less than a thirtieth of a second, both his weak link and tug driver are oblivious to any problem with the tow and are doing just fine.

Rooney used to shoot his mouth off about using safer weak links but never once either flew with or had anybody go up behind him with one. John Claytor used to babble about liking to fly with substantially fuzzed Standard Aerotow Weak Links but rearranged his neck in Ridgley's only low level lockout - the result of the 2014 East Coast Championship Safety Committee assholes decision to run the comp in insane crosswind conditions - and permanently crippled himself out of the sport.

So...

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How 'bout showing us the severity of this guy's injuries as a function of weak link strength on your graph if this glider locks out below 150 feet? And maybe you can recommend a good Helmet for this situation if you have an extra moment or two.

Hey Bob... His skills in recovering from the increase in the safety of the towing operation look to me like they could use a bit o' work...

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Shouldn't he be pushing out a bit more at this point to keep the glider from going upside down? Oh, I forgot. You have very little experience towing so you couldn't possibly comment. But keep up with the great graphs. No telling how many more lives those will save over the years.

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

"A bad flyer won't hurt a pin man but a bad pin man can kill a flyer." - Bill Bennett
"Never take your hands off the bar." - Tom Peghiny
"The greatest dangers are a rope break or a premature release." - Richard Johnson
Dennis Pagen - 1993/04
Performance Flying

Towline wear is also a problem since the line is typically dragged along the ground during restaging.
Next to a low stall and line break due to a gust, the event most likely to maim on tow is a lockout.
Dennis Pagen - 1998/01
Towing Aloft

The biggest danger in towing today is that which was the main problem from the start: the lockout.
---
As the towline wears from abrasion and UV exposure, its breaking strength diminishes. Typically pilots continue using a line until it begins to break on a regular basis at normal tow tensions. Given the general tendency by pilots to save money, it is probable that you will experience a line failure during a towing career.

The use of lighter tensions until some altitude has been achieved greatly reduces the probability of this occurring immediately after launch. The event is similar to a weak link break or release disengagement. Recover as you would with those occurrences. However, you will likely still have a length of line connected to your release.
Even in the era of frame towing the inconvenience stall was a more serious threat than the lockout.

In 1993 after a dozen years with the / the lower connection to the pilot and the advent of the Dragonfly the rope break is STILL the bigger threat.

But by 1998... :idea: :idea: :idea:

If we make the Infallible Weak Link a totally GOOD thing then the commercial operator is totally off the hook for anything that happens to the glider. Move the lockout to Threat Numero Uno and dumb the Infallible Weak Link down to barely sustainable then if your engine seizes, front end weak link blows, towline disintegrates; you fix whatever's going on back there it's the crash is the pilot's fault. He's supposed to be managing the flight so that he can handle an instantaneous loss of two to five hundred pounds of towline pressure no matter what else is going on at the time. And if it's the upper range flying with the Tad-O-Link was a poor judgment issue.
Zack C - 2012/06/02 02:20:45 UTC

I just cannot fathom how our sport can be so screwed up.
That's why.

http://www.hanggliding.org/viewtopic.php?t=2467
weak links
Jim Rooney - 2007/07/22 22:30:28 UTC

I've heard it a million times before from comp pilots insisting on towing with even doubled up weaklinks (some want no weaklink). I tell them the same thing I'm telling you... suck it up. You're not the only one on the line. I didn't ask to be a test pilot. I can live with your inconvenience.
It's not the back enders who are controlling the sport.

Bob spews the same rot 'cause...

http://www.ushawks.org/forum/faq.php
Frequently Asked Questions
Bob Kuczewski - 2010/08/13

For now, I'm going to take the US Hawks in the direction that I believe is right. If people want to go along, then they're welcome. If not, there are at least two other alternatives. :)
...he also likes monopolizing power.

Competence scares the crap outta all these motherfuckers and they're never gonna tolerate any significant level of it. Yeah, big fuckin' surprise but it's kinda fun really understanding the dynamics.
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Tad Eareckson
Posts: 9149
Joined: 2010/11/25 03:48:55 UTC

Re: Weak links

Post by Tad Eareckson »

Another UK AT incident:

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We know the weak link can't be much more than 0.8 Gs at most dangerous... So why doesn't it break? Is that glider not locked out sufficiently? It looks like Ollie Chitty thinks it is 'cause he's given up on flying it and is working on prying his easily reachable pro toad release open with one hand while flying the glider with the other.

How 'bout the tug weak link? Does it also not feel there's a problem worth addressing?

Would he have come out any worse with a 2.0 G Tad-O-Link?

Guess the tug thinks Ollie's doing fine 'cause he can blow the glider in a millisecond with a foot tripped actuator.

Good thing Ollie wasn't using one of these Kaluzhin jobs...

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Can you even imagine what it would be like to crash like that with one of those clips in your teeth?

One of those Koch chest crushers like we saw aborting that Plumpton lockout? One shudders to think.

Why do you think the tug doesn't blow him? People usually bring it back from that situation and it would be a pain to hafta do a go-around and set back up again?

And I JUST figured out how we got into this Ollie bullshit situation.

Here's Jonathan on his fourth and fifth ever (yeah, I'm making up these numbers but I'll leave it to Jonathan to set me straight if necessary) AT launches - which are nearly as brain dead safe and easy as platform launches:

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as described just two posts above. You hold yourself down on the cart, wing starts flying, trims nose down / keel lifts clear of the support, wait until you have crisp airspeed, gently nose up a wee bit until you lift out of the control bar supports as you let the hold-downs slip through your grips, lose the cart and wait for the tug to get off the ground.

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Starboard hold-down is dangling down and back free as a bird. This is a stupid blown launch kinda like:

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with much more serious results despite the extremely aircraft friendly environment and launch method. Who gives a rat's ass? 'Specially since the motherfucker can't be bothered to tell us how and why he got into that situation.

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Jim Rooney - 2011/08/28 10:40:24 UTC

Is a weaklink going to save your ass? Who knows? But it's nice to stack the deck in your favour.
This scenario DOES NOT EXIST. Never has, never will. If you rely on your Standard Aerotow Weak Link as lockout protection your recovery looks like:

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If you're nice and high you'll come out smelling like a rose. Otherwise you're DEAD. (Pity this motherfucker:

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Marc Fink - 2011/08/28 21:11:09 UTC

I once locked out on an early laminarST aerotowing. went past vertical and past 45 degrees to the line of pull-- and the load forces were increasing dramatically. The weaklink blew and the glider stalled--needed every bit of the 250 ft agl to speed up and pull out. I'm alive because I didn't use a stronger one.
didn't start out ten feet lower.)

In this day and age we have videos of EVERYTHING. If we don't have an example it doesn't exist in the real world. There's not a single reliable report from anywhere on the planet to support the use of a weak link as lockout protection.

Is a Rooney Link gonna save our ass? Neither Jim Keen-Intellect Rooney nor anybody else really knows. But we're stacking the deck in our favour with it.

http://www.hanggliding.org/viewtopic.php?t=14230
pro tow set-up
Jim Keen-Intellect Rooney - 2009/11/03 23:42:15 UTC

Ryan, Ryan, Ryan.... Hasn't anyone let you know that Tad knows everything?... and that the rest of us are complete morons?

I'll put Highland's (perfect) track record of over 60,000 successful tandem aerotows (yes, by this I mean ALL of them) against Tad's rantings.

Remember kids... always blame the equipment.
So then where are all the crashes we'd have when the stacked deck wasn't enough? If a tandem locks out at 250 and the weak link succeeds just in time to allow a pullout without a foot to spare does that count as a successful tow?

Actual PILOTS don't do stacked deck bullshit. If we think there will be a dice roll element in any particular flight we stay on the ground. The only serious launch incident in Highland Aerosports history occurred 'cause they were launching for a comp on shit dice roll equipment in shit dice roll conditions and they got a neck broken. And they scrubbed immediately afterwards - and if had been simple pilot error/incompetence rather than Safety Committee / Launch Director incompetence they wouldn't have scrubbed.

And another measure they didn't take was to continue with fifteen percent safer weak links. The one time in the history of hang glider towing in which we've seen that happen was at the 2005 Worlds after the clusterfuck Robin Strid lockout fatality which had absolutely nothing to do with anything above normal tow tension and the Bailey-Moyes douchebag response was to immediately mandate one-size-fits-all weak links incapable of getting the gliders airborne.

And if that doesn't prove beyond a shadow of a reasonable doubt that the actual cause of the fatality was massive incompetence at the top level I don't know what will.
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