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).
I figured everyone's using it since "this stuff's been worked on and worked over for years and thousands upon thousands of tows."
So what makes you believe that 200lb line breaks at 200?
Zack C - 2013/03/05 03:39:52 UTC
A loop of 200 lb Greenspot has been tested to break around 200 lbs. Also, load tests have shown that a loop of any material attached to a Spectra bridle will break at approximately the breaking strength of a single strand of that material.
Jim Rooney - 2013/03/05 05:15:25 UTC
So then how can you claim that a double link of 130lb = a 200lb link?
Zack C - 2013/03/05 15:16:23 UTC
Because it's been experimentally verified that two loops of 130 break around 200. I've already quoted Davis/Quest's results and told you I know people with load testers that have also confirmed this. I've also said that experimental verification has shown a loop of 200 to break at 200.
Just as two strands of line do not have double the breaking strength of a single strand, four strands do not have double the breaking strength of two strands.
You've repeatedly assigned sentiments to me I never expressed, ignored my questions, and asked me questions I've already answered. I'm beginning to wonder if you're actually reading what I'm writing.
Jim Rooney - 2013/03/11 18:59:06 UTC
Now, I pro tow with a 130lb weaklink. I'm 160lbs soaking wet. The protow cuts the force seen by either side of the bridal in 1/2, so I'm overloading the release with over 2X's it's achievable load.
Zack C - 2013/03/11 20:54:09 UTC
You were loading the release directly to 160 lbs, right? If so, that's only 1.2 times it's achievable load with a 130 lb weak link.
Jim Rooney - 2013/03/11 20:57:51 UTC
Sorry, yes it's early... Just under... As you've said many times... 130 breaks at100 right?
I'm 160.
Zack C - 2013/03/11 21:11:28 UTC
I suspect you're trolling, but if not, I've said many times that
- 2 strands of 130 breaks at 130
- 2 strands of 200 breaks at 200
- 4 strands of 130 breaks at 200
Oh, btw... before you go there, cuz it is where you're headed... please note the word "Guidelines".
As I said.
Been through this shit a million freaking times.
Please quit trying to educate me about my job.
Quit trying to educate Rooney about his job. (Like trying to teach a fuckin' pig to sing...) He's been through this shit a million freaking times.
Pity he doesn't have any freaking clue as to actual breaking strengths or, for that matter, what the fuck he's talking about - then he'd probably only have to go through this shit one or two freaking times.
Dr. Lionel D. Hewitt, professor of physics and developer of the 2-to-1 center-of-mass Skyting bridle for surface towing, is well respected for his knowledge of towing, bridles, and weak links. His position on weak link strength for aerotowing of hang gliders seems to be consistent with ours. He has acknowledged that we especially need to avoid inadvertent weak link breaks while aerotowing, because much of aerotowing takes place over unlandable terrain.
BTW, this weaklink as a lifeline comment... any tow pilot that takes you over something you can't get out from should be shot. It is one of the cardinal rules of towing. Again, "I wana believe" rationalization.
Actually up in the northwest, it's a bit more expensive.
Tow rating is $200, including tows and instruction.
Tandems are $125 each. So, it's actually closer to $450 for a tow rating in the northwest. That's if you can somehow convince them to do a tandem as the park is not tandem friendly and makes the tow much more dangerous for everyone, especially the tug pilot.
The thing you have to realize is, adding the tandem requirement to the mix really increased the danger for everyone. For certain flight parks it was safer without this tandem requirement, not even counting the increased costs. Not every flight park is Quest with unlimited room to bail out in an emergency situation. The latest rules are really sad for our sport, but I suppose something is better than nothing.
Tracy Tillman - 2011/02/10 20:36:01 UTC
How do the sailplane clubs do it in the northwest? Have they found dual flights for aerotow instruction more dangerous than solo flights for aerotow instuction? Explain why you think the situation for hang gliding aerotow instruction is different.
Dave Scott - 2011/02/10 20:53:32 UTC
The sailplane clubs do it with a tandem, they always have. I don't think you can compare them, it's apples to oranges.
The situation you have with hang gliding is... Couple a Dragonfly with a 582 engine, and you can tow fine with a single pilot and get a good climb rate, however with a Tandem you have a terrible climb rate. Now combine this terrible rate with an already small field and you have a situation that could lead to a death or serious injury of either party. All it takes is one engine out and you're done!
My thoughts are it's safer to NOT require a tandem in this situation.
So, I can already hear the argument on the regulators side. Just get a 912 engine and or a bigger field. Sure, that would solve it, but I think you will find that if that is where it has to go, then it will just be another tow park shutting down.
When I got my rating at this tow field, it was a hundred and fifty bucks, now it's going to be over four hundred bucks, if it's even possible at all now. It may be that anyone on the west coast will have to fly to Quest to get this done.
Weak links don't always break in lockout situations... so lets make them stronger? Are you nuts?
I don't care if they're "Meant" to break in lockout. How the hell is it a bad thing if they do?
You're advocating making tow systems more dangerous for the sake of definitions. Here in reality, weak links work. They may not suit your definitions, but you're on crack if you think they're not doing people good.
And yes, get behind me with a "strong link" and I will not tow you.
Jim Rooney - 2007/07/22 16:59:30 UTC
Go ahead and try to improve your release... whatever. Just don't tell me that weaklinks need to be stronger! That's just flat out ignorant.
Just because you think about something a lot or talk about something a LOT doesn't make you right... you can easily chase the wrong idea around for years.
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).
We had six weaklink breaks in a row at Zapata this year. Russell Brown (tug pilot, tug owner, Quest Air owner) said go ahead and double up (four strands of Cortland Greenspot).
Jim Rooney - 2011/08/31 09:25:57 UTC
You've not heard about strong-link incidents.
Uh, yeah... cuz we don't let you use them.
I'm not sure who you're arguing with Zack, but it's sure not me... cuz man... you've got some pretty big hangups mate.
Ra ra ra... burn the greenspot!!!!
Get real man.
You think that's all we use?
Hell, just in this thread, you seem to have missed the 200lb orange links.
Ah, but your strawman argument lives and breaths by your black and white hyperbole.
When you come back to reality, let me know.
Till then, I'm sick of it.
Yes, there most assuredly are bad situations in which one REALLY needs to stay on tow and not have someone on the other end of the line whose knee-jerk response to every undesirable situation is to squeeze a lever.
Bill/Mike.
At some point during that tow that glider entered the living-on-borrowed-time envelope. It was low and slow. Assuming that the trike was running with a full head of steam - and I'm pretty sure it was - the action that its driver needed to take was to pull in and maintain said steam. That didn't happen.
If tow line tension gets reduced or lost because:
the tug trades in some speed for altitude;
the RPMs diminish or stop advertently or in-;
a lever or lanyard is hit or pulled; or
a weak link pops
the glider goes from having an angle of attack way too high to having one way way too high. Need I continue?
1996/05/11. Rerun - but apparently one needs to say things over and over.
Four glider pilots - one of them cringing behind a piling, another running full tilt for shore, a third locked out and about to slam into the dock right where Ray Dunmyer is cowering and yours truly had been standing, a fourth applying full throttle to the winch.
Contrary to what the crowd present is anticipating, the glider is able to benefit from the reduced AOA provided by Jonny Thompson enough to get the starboard wing tip flying more on par with its mirror image and Lawrence Battaile not only survives but is able to get up and make a few passes soaring the tree line at Colington Island.
Neither a cut engine, flimsy weak link, three-string release, hook knife, nor philosophy of a rope donation being a panacea would have been been a positive contribution to the situation.
Brian Vant-Hull - 2007/08/03 19:34:15 UTC
Now THAT's interesting enough to suck me back in.
Jim... I concede that Tad's saying that staying on tow is sometimes healthier than getting off. Wasn't expecting that, you read it right I read it wrong.
But I see what he's saying. We tow-launch with a nose angle that in nearly all other circumstances would send us into a stall. The only thing that keeps us going is a tug that obstinately refuses to let the increased drag slow us down so much we lose lift. We're going fast enough when we release from tow that we recover from stall before we drop below 1 g of lift, so don't go into a dive.
Maybe if the nose gets too high releasing from tow is dangerous?
Of course not, Brian. If it were would Dennis write:
Towing Aloft - 1998/01
Pro Tip: Always thank the tug pilot for intentionally releasing you, even if you feel you could have ridden it out. He should be given a vote of confidence that he made a good decision in the interest of your safety.
I leave this up to the very experienced tow-meisters to weigh in on.
Of course you do, Brian. Leave it up to the very experienced tow-meisters who've given us inaccessible brake levers velcroed onto downtubes, inaccessible bent pin barrel releases on our shoulders, the better part of two decades worth of One-Size-Fits-All Miracle Fishing Line, and nose high gliders incapable of stalling when...
Wills Wing / Blue Sky / Steve Wendt / Ryan Voight Productions - 2007/03
NEVER CUT THE POWER...
Reduce Gradually
Increase Gradually
...the power is cut.
Fuckin' goddam worm. Take your physics degree and shove it where nothing from the visible light spectrum penetrates.
Except for the normally high nose angle I'd say being off tow is safer too.
Yeah Brian. And except for the normal hypothermia and drowning issues being in the water is safer than being on land. You're much less likely to be trampled to death in a buffalo stampede.
Jim Rooney - 2007/08/04 10:43:15 UTC
No.
If you're that high on tow, you've put ME in harms way.
I watched the glider come almost straight down from about 250 feet. I saw that Jeremiah was doing the takeoff right from the start and I watched him get pretty low on the tow as the tug crossed the road at the end of the runway.
Mike Van Kuiken - 2005/10/13 19:47:26 UTC
The weak link broke from the tow plane side. The towline was found underneath the wreck, and attached to the glider by the weaklink. The glider basically fell on the towline.
Chicago Sun-Times - 2005/10/06
"They're 200 feet in the air, and while normally they would glide to the ground, this hang glider nose-dived to the ground," attorney Matthew Rundio said. "We need to find out why that happened."
Freak accident, Matt. Probably hit an invisible dust devil.
- And, of course, the laws of physics guarantee that you're ALWAYS gonna have...
Last year, at LMFP I saw an incident in aerotow that resulted in a very significant impact with the ground on the chest and face. Resulted in a jaw broken in several places and IIRC some tears in the shoulder.
...Mach 5 takeoff and need the weak link to save your ass.
...you're driving me into the ground (at near stall speeds for me btw).
With ALL DUE RESPECT, Jim... This is an ENTIRELY unfounded fear. As long as the glider isn't using a stronglink...
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.
The problem with strong links (neither Bobby Bailey nor I was aware at the time of the US Nationals that pilots were doing this) is that they endanger the tug pilot. If the hang glider pilot goes into a lock out, and doesn't break the weaklink (because there isn't one), they can stall the tug.
...it's physically impossible for the tug to stall. This is why Dragonflies almost always have a glider with a Rooney Link on it on takeoff. If the glider starts dragging too much the Rooney Link will pop and the tug will automatically accelerate and fly away - just like the glider. Win/Win. And this is from Bobby Bailey - and he's a fucking genius when it comes to this shit.
This is one of the prime situations where I will pass out ropes.
Hey Jim...
- If the glider sits on the cart until the tug lifts off it's going Mach 5. How come the tug is at near stall speed?
- Really amazing the way you guys are always taking off so close to stall speed yet never seeming to actually stall. Really gotta hand it to ya - totally righteous stuff.
The other is low level lockout, in case you're interested.
Goddam right I'm interested!
- Just how many ropes have you given to save somebody's life?
- In my experience and observations the glider tends to go down like a fuckin' brick...
...after it's popped or been popped off of a lockout. What percentage of the people you've saved from low level lockouts have made it to shock trauma with detectable pulses?
- What's causing these low level lockouts:
-- the glider's lack of adequate tandem Cone of Safety training; or
-- your incompetence in launching them into thermals or dust devils?
- How come you're able to beat the Rooney Link but the glider isn't? You think you have an advantage over them because YOUR dump lever is on the joystick, you just need one hand to fly your plane, and you don't hafta reach for anything? Or is it entirely a matter of the muppets you tow being too stupid to know when to surrender what remaining control they have and execute the easy reach with...
Oh it happens.
I have, all the guys I work with have.
(Our average is 1 in 1,000 tows)
Oh yeah... an other fun fact for ya... ya know when it's far more likely to happen? During a lockout. When we're doing lockout training, the odds go from 1 in 1,000 to over 50/50.
...an under fifty percent expectation of surviving if he makes it that far and the lever doen't rotate around the downtube?
- If all these gliders locking out low are using Rooney Links how are they getting into low level lockouts to the point at which you need to dump them?
- These sound like EXTREMELY serious incidents. How come:
-- you're not reporting them? (I'm guessing it's a modesty issue.)
-- the survivors aren't reporting them?
-- friends, witnesses, tow park operators aren't reporting them?
-- we're not seeing any videos?
- SURELY you're not the ONLY tug driver pulling muppets into dust devils. How come none of your colleagues are reporting these incidents? Is it because they're not as good as you are about giving people the rope and they don't want the word to get out about the high fatality rates of the muppets behind THEIR tugs?
- Did you talk to Tex Forrest after he dumped Holly Korzilius into a near fatal lockout impact to help him improve his technique?
Rest assured, if you get the rope, you've scared the hell out of me.
Really? I can't recall an account of ANY tug driver with a release that wasn't a glider caliber total piece of shit (Chris Bulger, Dave Farkas) having much of a problem while towing someone into a violent lockout at altitude or a violent impact down low...
- Corey Burk - Rob Richardson
- Chad Elchin - Tad Eareckson
- Arlan Birkett - Mike Haas
- Bobby Bailey - Robin Strid
- Neal Harris - Dennis Pagen
- Sunny Venesky - Tad Eareckson
- Tex Forrest - Holly Korzilius
- Lisa Kain - John Dullahan
- Zack Woodall - Carlos Weill
- Mark Frutiger - Zack Marzec
...having any noteworthy control issues.
Are you SURE you're getting so close to the edge of your survival envelope on all these critical low level lockout emergencies that you're pulling out of the fire?
Or are you just imagining that must be what it would be like if it ever ACTUALLY HAPPENED?
I don't want to smash into the earth...
Probably oughta give a bit more thought to...
The Press - 2006/03/15
The Civil Aviation Authority (CAA) is urgently pushing for new hang-gliding industry standards after learning a hang-gliding pilot who suffered serious injuries in a crash three weeks ago had not clipped himself on to the glider.
Extreme Air tandem gliding pilot James (Jim) Rooney safely clipped his passenger into the glider before departing from the Coronet Peak launch site, near Queenstown, CAA sports and recreation manager Rex Kenny said yesterday.
However, he took off without attaching himself.
In a video, he was seen to hold on to the glider for about fifty meters before hitting power lines.
Rooney and the passenger fell about fifteen meters to the ground.
...hook-in checks then. I imagine your passengers aren't all that keen on the idea EITHER.
...and I don't want you to smash in either.
Get your own shit together before you start worrying about the other end of the string - pigfucker.
But losing the line, especially at the decision of a piece of string, may be the worst thing that could happen to a glider in some situations.
This isn't about convenience.
Jim Rooney - 2013/03/05 05:15:25 UTC
Nonsense.
It's completely about convenience.
People like to argue about it and in their arguments, they dig up rationalizations of it not being about convenience, but sorry... it very much is about convenience.
This is hang gliding, hang gliding is a (clueless, warped, corrupt) flavor of aviation, aviation is...
One more thing I'll add...I don't think of this sport as 'an art and a science'. Music and paintings are art. Aviation is pure science. I'm not saying feel and intuition aren't important - in fact I believe they are, but ONLY because they compensate for a lack of understanding of the science.
Flying is unintuitive and a reliance on intuition is dangerous. This is one of the main points of Langewiesche's "Stick and Rudder".
...pure science, and there are no ARGUMENTS about the science. There are people who understand the science and know what the fuck they're talking about attempting to educate the clueless and expose and discredit the liars and frauds such as yourself, Davis, Jack, Bob, Trisa, Dennis. There's no more an argument between the One-Point-Fivers and Rooney Linkers than there is between evolutionary biologists and Southern Baptist creationists.
And your definition of an ARGUMENT is any statement contrary to any of your proclamations from anybody with an IQ in the mid double digits or better who doesn't have his nose stuck up your ass.
When you tell us that we're using Rooney Links because they:
- were worked out through trail and error
- will limit angle of attack
- increase the safety of the towing operation
and we say otherwise, we're not ARGUING with you. We're calling you a liar and telling you you're full of shit.
Take if from the other angle... if it were about safety... if you are truly concerned about your safety... why are you towing?
If YOU are truly concerned about OUR - or your - safety... why are you towing US?
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.
Oh yeah... an other fun fact for ya... ya know when it's far more likely to happen? During a lockout. When we're doing lockout training, the odds go from 1 in 1,000 to over 50/50.
...fail in lockout situations over half the time - even if you CAN get to the actuators.
- Roy Messing proved beyond any shadow of a doubt - in dead morning air - that neither...
Is a weaklink going to save your ass? Who knows? But it's nice to stack the deck in your favour.
...his Rooney Link, Lockout Mountain Flight Park Release, hook knife, or (unnamed) tug driver making a good decision in the interest of his safety are likely to be of much use in a low level lockout.
Yesterday we had our tug crash shortly after takeoff up here at SOGA ontario. From what I understand the plane stalled shortly after takeoff and had a very rough landing. Pilot peter was airlifted out. Tug looks like writeoff. Lets hope our friend recovers ok.
Tug was a dragonfly. Glider was a u2 I believe - flexwing for sure. We took the tug apart this morning its pretty badly damaged. Probably a writeoff. From what I gathered he stalled at about 80ft and came down hard - pilot cage was all mangled when I saw it. pilot had serious injuries but not critical. Very un fortunate
...is proving by spending the rest of his life in a wheelchair that Rooney Links don't provide very good stall protection for Dragonflies. And a bit over fifteen months later Frank Murphy...
...further undermined the position that Rooney Links are of much use in increasing the safety of the towing operation.
And then on 2013/02/02 Zack Marzec proved pretty definitively...
Not only is it realistic, it is also correct.
The pilot suffered a heart attack.
Let it go
Jim Rooney - 2013/06/06 12:39:18 UTC
Looks like my guy that "talked to the examining doctor" was wrong.
Oh well.
...why Charles Matthews' Dragonfly went down at Lockout on 2012/05/26?
The answer of course is that it's not actually about "safety".
Oh. The weak link is...
Towing Aloft - 1998/01
A weak link is the focal point of a safe towing system.
...the focal point of a safe towing system - but we're not supposed to discuss its strength or the effects when it does or doesn't increase the safety of the towing operation.
People get pissed off not because the weaklink breaking made their lives scary...
Nah. Definitely not scary...
Lauren Tjaden - 2003/12/14
This fall at Ridgely, I had a weak link break at maybe fifty feet. I thought I was going to have to land in the soybeans - the very tall soybeans - when I looked at my angle. But, my glider stalled quite dramatically almost instantly (hard not to stall when you have a break), and dove towards the ground (a bit disconcerting from so low).
Last year, at LMFP I saw an incident in aerotow that resulted in a very significant impact with the ground on the chest and face. Resulted in a jaw broken in several places and IIRC some tears in the shoulder.
...in the jaw and shoulder - but just for the muppets with no towing ability whom you don't trust to release when they should and need the Rooney Link to keep them from getting into too much trouble.
They missed the thermal.
And I can't imagine why, given recent incidents...
Ok, as long as we're digging this deeply into it....
It is not merely a matter of inconvenience. I was there, and in my oppinion Steve came rather close to breaking his legs. I was getting ready to dial 911.
Sure, being on tow at the wrong time is an extremely bad thing. But don't tell us that being off tow at the wrong time is all sweet and wonderful. Yes, we prepare for it, but that doesn't make it a safe situation. It makes it a manageable situation. There are times where it's better to be on tow than off tow.
...to MANAGEABLE. And "manageable" is when a guy who scored his Four a decade and a half prior - and a dozen years before you arrived on the scene to grace us with your Keen Intellect - is rather close to breaking his legs and you're getting ready to dial 911.
Ask anyone that's dragged a dolly into the air.
But let's not ask Steve Kinsley - who misused a release and fired it prematurely - or Shane Nestle...
So far I've only had negative experiences with weak links. One broke while aerotowing just as I was coming off the cart. Flared immediately and put my feet down only to find the cart still directly below me. My leg went through the two front parallel bars forcing me to let the glider drop onto the control frame in order to prevent my leg from being snapped.
...who found himself in a similar but much worse manageable situation as a sole consequence of a Rooney Link increasing the safety of the towing operation because:
- anybody who isn't a total moron can easily remove the dolly dragged into the air component from the equation
- NOBODY using a Rooney Link can be assured of not getting dumped back on a launch dolly - or on his face on the runway.
Take if from the other angle... if it were about safety... if you are truly concerned about your safety... why are you towing? Why are the people that are arguing about weaklinks towing?
The answer of course is that it's not actually about "safety".
Right.
- rating requirements
- training programs
- glider handling and performance
- sprog settings
- preflight inspections
- maintenance schedules
- hang checks
- Aussie Methodism
- hook-in checks
- launches
- wind indicators
- wire crew coordination
- ramp design
- XC tasks
- site restrictions
- right of way rules
- FARs
- aerobatics
- approach patterns
- landings
- wheels
- skids
- helmets
- release actuator placement
- pro versus muppet towing
- weak link regulations
- funky shit
- parachute design
- incident reports
Anybody who discusses ANY of this issues isn't TRULY concerned about safety... If they were they wouldn't be flying. Hang gliding is just one big crap shoot and we're all best off just doing and using whatever everybody else is because if there were anything better, we'd all be doing and using it already.
In the old threads there was a lot of info from a guy named Tad. Tad had a very strong opinion on weak link strength and it was a lot higher than most folks care for. I'd focus carefully on what folks who tow a lot have to say. Or Jim Rooney who is an excellent tug pilot. I tow with the "park provided" weak links. I think they are 130 pound Greenspot.
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.
Hey Million Comp Pilots...
Really appreciate all the support you gave us back in February and March when we had Rooney, Davis, Paul, Lauren, Russell, Dennis, Trisa, and all these Dragonfly / Flight Park Mafia / USHGA / BHPA / HPAC / 130 pound Greenspot motherfuckers totally on the ropes. Keep up the great work.
In the your "Higher Education" article in the magazine a year ago you wrote:
Dr. Trisa Tilletti - 2012/06
Dr. Lionel D. Hewitt, professor of physics and developer of the 2-to-1 center-of-mass Skyting bridle for surface towing, is well respected for his knowledge of towing, bridles, and weak links.
And Dr. Lionel D. Hewett (if you wanna spell his name right) states on the issue of weak links:
Donnell Hewett - 1985/08
The system must include a weak link which will infallibly and automatically release the glider from tow whenever the tow line tension exceeds the limit for safe operation.
But in the 2011/05, 2011/11, 2012/06 SOPs you include the statement that:
The United States Hang Gliding and Paragliding Association, Inc.
Standard Operating Procedure
12. Rating System
02. Pilot Proficiency System
12. Hang Gliding Aerotow Ratings
-C. Aerotow Equipment Guidelines
-6. The purpose of the weak link is to protect the tow equipment, and may not prevent lockouts or other abnormal flight conditions.
which appears to me to be something of a contradiction and expression of disrespect.
Oh, wait...
In the 2013/02/07 / latest version - published just five days after Zack Marzec slammed in at Quest after his Hewett Link actually DID prevent him from getting into too unusual an abnormal flight condition - you deleted that disclaimer - along with every existing reference concerning weak link specification and configuration, including the allowance of twice Dr. Hewett's one G limit.
Really appreciate that very definitive show of respect.
I don't know if you heard or not but four and a half months ago a tandem aerotow instructor - shortly after launch and right in the middle of the Cone of Safety - hit a monster thermal, and rocketed up until his standard aerotow weak link popped. Then he whipstalled, tailslid, tumbled, and died doing what he loved.
We really can't figure out what went wrong.
Some of the people from The Flight Park Tad Runs seem to think the standard aerotow weak link may have been a little too light for the situation and that it may have been a relevant factor but...
In the old threads there was a lot of info from a guy named Tad. Tad had a very strong opinion on weak link strength and it was a lot higher than most folks care for. I'd focus carefully on what folks who tow a lot have to say. Or Jim Rooney who is an excellent tug pilot. I tow with the "park provided" weak links. I think they are 130 pound Greenspot.
...Jim Rooney, who is an excellent tug pilot and makes a pretty good case that...
You're afraid of breaking off with a high AOA? Good... tow with a WEAKER weaklink... you won't be able to achieve a high AOA. Problem solved.
...a WEAKER weak link will solve the problem by preventing you from achieving a high angle of attack.
I thought it would be a good idea for me to reread your excellent article on weak links from a year ago, see what I could learn, and brush up on my understanding of the differences between de jure, de facto, nominal and actual loops of 130 pound Greenspot.
In the course of the review I noted many references to USHGA's weak link recommendations:
HIGHER EDUCATION - 2012/06
TIE A (BETTER) WEAK LINK
by Drs. Lisa Colletti and Tracy Tillman
---
In contrast, USHPA aerotow guidelines recommend a weak link breaking strength of 1G, which is 100% of the actual operating weight of the hang glider.
---
I'll explain how that works by comparing FAA weak link requirements with USHPA recommendations for (a) a very light, small hang glider, (b) a larger heavier hang glider, and (c) a tandem glider.
---
If a pilot hooks in at the high limit of 190 lbs., then per USHPA's recommendation of using a 1G weak link, the weak link should have a breaking strength of the actual 235 lb. operating weight of the glider, which is within the FAA required range of 188 to 470 lbs. If a pilot hooks in at the low limit of 120 lbs., then per USHPA's recommendation of using a 1G weak link, the weak link should have a breaking strength of the actual 165 lb. operating weight of the glider, which would be below the FAA required range of 188 to 470 lbs.!
---
As such, USHPA's 1G recommendation for weak link strength for a weak link on a V-bridle is considered a nominal 1G value, rather than an actual 1G value.
---
So when an actual 1G weak link is placed directly in line with the tow rope, it will not be FAA-legal across the pilot hook-in weight range of the glider--but a USHPA-recommended nominal 1G weak link placed on one end of the V-bridle will be legal across the pilot hook-in weight range for the glider and is relatively in the middle of the FAA's required range for breaking strength.
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When we look at gliders and pilots of more average size, the standard 260 lb. weak link placed on the end of the V-bridle is FAA-legal for most gliders and pilots, and closer to the USHPA nominal 1G recommendation.
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There is no specific range of tolerance specified for USHPA's nominal 1G recommendation--it is not meant to be an exact requirement.
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It is a de facto standard, because it works for most pilots and gliders and is usually near the USHPA recommendation of a nominal 1G weak link for most pilots. For example, a mid-size Sport 2 155 with a pilot who has a hook-in weight that is in the middle of the recommended weight range will weigh about 260 lbs., so a loop of 130 lb. line is just right.
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For example, if the total weight of a tandem glider with pilot and student is 416 lbs., then per the USHPA recommendation of using a nominal 1G weak link, the weak link on the tandem glider's V-bridle should be 416 lbs. and no more than 520 lbs. for the V-bridle on the tug.
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It could be hard on the equipment and could be illegal if the tug is using a weaker weak link. It is also far beyond USHPA's nominal 1g recommendation.
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The climb angles were shallow and the tow forces were lighter, so an actual 1G weak link used in-line with the tow rope was practical--and likely the basis for creation of the original 1G USHGA recommendation for weak link strength.
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The USHPA recommendation of making a weak link with a 1G breaking strength still applies, but the 1G weak link is now normally placed on one end of the V-bridle instead of onto or in line with the tow rope. The current 1G recommendation is a nominal value, whereas the original 1G recommendation was an actual value.
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This is near to what actually results when a USHPA-recommended nominal 1G weak link is placed at the top end of a V-bridle used for aerotowing.
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But when I pulled up the current version of the SOPs I could find ABSOLUTELY NOTHING in the way of any recommendations. I noted that the revision was made just five days after the tragedy occurred and my best guess is that the new recommendation will be for something thirty or forty pounds lighter. But I'm feeling like I'm flying a bit blind now.
Any idea when the testing will be complete enough to give us some idea of what strength fishing line we should be stocking up on? I certainly don't wanna rush the project any but we're already a fair bit through the season and there are a lot of people looking for some kind of guidance from the people they've always known they could trust.
Two or three decades ago before the sport was totally infested with and taken over by parasites, dregs, and frauds like you we had a few good people in key positions here and there getting things right, taking positions, and saying the right things...
Doug Hildreth - 1981/04
Just before the first step of your launch run, lift the glider and make certain that the straps become tight when you do so.
...even if the parasites, dregs, and frauds who constituted a healthy majority of the sport made sure...
Doug Hildreth - 1990/03
The other significant increase is in failure to hook in. Typically there are about the same number of non-hook-ins in the questionnaire group, so that it is safe to say that there were at least ten failures to hook in this year. It has occurred in the tandem sector too, both pilot and passenger.
The instructional programs to assure hook-in within fifteen seconds of launch have apparently not caught up with the masses.
...very little good ever came of their efforts.
And we also had people with reasonable levels of integrity...
Gil Dodgen - 1983/05
The early days of hang gliding were marred by numerous towing accidents. During this period this aspect of our sport established a hopelessly bad reputation. And, indeed, last year, as you may have noted in Doug Hildreth's recent accident review, there was a towing fatality by a totally inexperienced Texas pilot.
Some time ago I received a series of four articles on a new towing system from Texas experimenter and inventor Donnell Hewitt. I ran the first in the series of four articles. Editors learn from experience and if I could roll back the calendar I would run all four at once in condensed form. In fact, what happened was that the first article - which made seemingly outrageous claims without outlining the actual technique or hardware - inflamed the then towing establishment...
...at least TRYING to do the right thing - even if they were mostly off target.
For over thirty years now that idiot goddam piece of fishing line that constitutes the focal point of Donnell's idiot goddam safe towing system has been...
Donnell Hewett - 1981/10
Now I've heard the argument that "Weak links always break at the worst possible time, when the glider is climbing hard in a near stall situation," and that "More people have been injured because of a weak link than saved by one."
...crashing gliders left and right by dumping them off of tow and into manageable situations.
And four and a half months ago a Tandem Aerotow Instructor flying dead center in the Cone of Safety - and, within the confines of his Industry Standard equipment, doing everything right - several seconds later found himself in a manageable situation tumbling to his death.
And the primary reason he found himself in such an extremely manageable situation was so obvious that you parasites, dregs, and frauds had to invent a dust devil to hold your story together.
And to cover your sleazy asses you deleted from the USHGA Aerotowing SOPs every reference to standards for the focal point of our safe towing system - along with every reference to every lesser component.
There is no fuckin' way that's not an indisputable first in the entire world history of aviation. And so far - thanks to over three decades of lowering the expectations of and dumbing down the participant population - you've gotten pretty much clean away with it.
Congratulations.
What have you got in store for us next? An Aerotowing SOP outlawing launching into dust devils and a fourteen page magazine article explaining why this formerly common practice is no longer acceptable?
