Tad -
I'm confused. How can you blame the weaklink in your posted accident report when it clearly says the pilot did not make an attempt to use his release? Maybe I'm missing something, but wouldn't that be pilot error? If you are in lockout, than you as the pilot have made a bad decision in not getting off tow! Yes the weak link broke, but that wasn't the cause of the accident. The cause of the accident was getting into lockout in the first place. The broken weaklink was just a secondary order of effect. Most pilots are obstinate in thinking they can fly themselves out of a pilot induced ocillation, when in fact it would be MUCH safer to release before the PIO gets to the point of lockout. The stronger weaklink that you suggest would just complicate the matter worse in this situation. You'd just do your replication of a "Gayla Bat-Kite" and fly it straight into the ground. Short & simple - The weaklink did what it was supposed to do ... the pilot didn't.
weak links
Moderator: CHGPA BOD
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Flying Lobster
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Chris, Marc,
EXACTLY!!
That was pilot error.
If you are in lockout, then you as the pilot made a bad decision in not getting off tow!
Who said I was blaming the weak link?
The weak link didn't make any difference. It was a single loop of 130, it could have been ten thousand pound steel carabiner, the results would have been exactly the same.
(I don't think he was being obstinate or cocky - I think he was too scared to take his hand off the basetube and, according to Bill Moyes, shouldn't have had to but I don't want to digress right now.)
Chris - The guy died. How could a stronger weak link have made things worse?
Dan (Tomlinson) still thinks that dumbing down the weak link makes things safer. Read the title of Danny (Brotto)'s post -
"Weak links are not a secondary release system..."
(That's DOCTOR Freeman, by the way, I realize now I had taken note of him before as a result of an Oz Report reference.)
If the glider gets crooked low to the ground you need to do whatever it takes to get it straight. When we're free flying we have a reflexive weight shift response. When we're on tow we may need to supplement that action with a reflexive action with respect to a release actuator.
When we understand that dumbing down the weak link doesn't make us safer then we can start using them in the middle of the safe range- 1.4 Gs - rather than off the bottom end of it.
EXACTLY!!
That was pilot error.
If you are in lockout, then you as the pilot made a bad decision in not getting off tow!
Who said I was blaming the weak link?
The weak link didn't make any difference. It was a single loop of 130, it could have been ten thousand pound steel carabiner, the results would have been exactly the same.
(I don't think he was being obstinate or cocky - I think he was too scared to take his hand off the basetube and, according to Bill Moyes, shouldn't have had to but I don't want to digress right now.)
Chris - The guy died. How could a stronger weak link have made things worse?
Dan (Tomlinson) still thinks that dumbing down the weak link makes things safer. Read the title of Danny (Brotto)'s post -
"Weak links are not a secondary release system..."
(That's DOCTOR Freeman, by the way, I realize now I had taken note of him before as a result of an Oz Report reference.)
If the glider gets crooked low to the ground you need to do whatever it takes to get it straight. When we're free flying we have a reflexive weight shift response. When we're on tow we may need to supplement that action with a reflexive action with respect to a release actuator.
When we understand that dumbing down the weak link doesn't make us safer then we can start using them in the middle of the safe range- 1.4 Gs - rather than off the bottom end of it.
I give up ... What exactly is your point in this whole thread? And what relevance did the accident report have to with this thread? Your logic train has derailed and I'm jumping off before it goes over the cliff. Fly how you want, with what equipment you want, blah blah blah. When you start showing empirical data with proven and qualitative results instead of clouding the issue with conjecture, misquotes, and speculation maybe I will be more inclined to listen, but right now it just seems you are grasping at straws and I have no clue what the point in all of this is.
By the way, sailplanes weigh considerably more than hang gliders, yet take off in the same conditions. One could extrapolate that the effect of the turbulence we feel in a HG would be significantly less than the sailplane experiences do to much more inherent stability. You also have moving control surfaces, longer wingspan, etc when make towing a much more controlled experience than HG. I think there are WAY to many variables that you are not including in your simple analysis when trying to compare towing a hang glider vice towing a sailplane. Apples do NOT = Oranges under most circumstances unless you are calling them both fruit.
P.S. Neither Apples nor Oranges have a good glide ration.
By the way, sailplanes weigh considerably more than hang gliders, yet take off in the same conditions. One could extrapolate that the effect of the turbulence we feel in a HG would be significantly less than the sailplane experiences do to much more inherent stability. You also have moving control surfaces, longer wingspan, etc when make towing a much more controlled experience than HG. I think there are WAY to many variables that you are not including in your simple analysis when trying to compare towing a hang glider vice towing a sailplane. Apples do NOT = Oranges under most circumstances unless you are calling them both fruit.
P.S. Neither Apples nor Oranges have a good glide ration.
I think Tad is saying the following:
1. The initial force when the tug begins to accelerate the glider is greater than the force experienced during a lockout.
2. Hence any weak link that would protect you from a lockout would have broken before you get off the ground.
3. Hence we are wasting our time with weak links that keep breaking on us.
The only problem I see is if this reasoning is correct why do weak links keep breaking in the air? If assertion #1 is incorrect then we definitely do not want links that never break.
So explain why weak links break in the air instead of at the initial pull and I'll be satisfied. But it truly needs to be a good explanation.
1. The initial force when the tug begins to accelerate the glider is greater than the force experienced during a lockout.
2. Hence any weak link that would protect you from a lockout would have broken before you get off the ground.
3. Hence we are wasting our time with weak links that keep breaking on us.
The only problem I see is if this reasoning is correct why do weak links keep breaking in the air? If assertion #1 is incorrect then we definitely do not want links that never break.
So explain why weak links break in the air instead of at the initial pull and I'll be satisfied. But it truly needs to be a good explanation.
Brian Vant-Hull
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
OK (sigh), back down into the gutter...
Chris,
I'm not the least bit surprised that you have no clue. Lemme tell you what I told Marc a few posts ago. You have yet to request the documentation I first offered to make available to anyone on the list a couple of weeks shy of two years ago. It's loaded with data.
And, oh yeah Chris, what's the data on the stuff you're currently using?
My points are (listen carefully now)...
1. One size does not fit all (Marc), especially if that size is off the bottom end of the reliability range.
2. We can use high quality weak links in the middle of the safety range and totally eliminate any weak link break which does not involve a pilot who has really fucked up IF we don't continue to behave as a large herd of stupid sheep (fat chance).
With respect to sailplanes...
Last fall I consulted with a sailplane pilot who is also an AT release designer and learned that sail planes are, as you speculate, no brainers to control on tow.
First of all, the upper weak link limits are not mine. They are set by the FAA and the USHGA Towing Committee to cover the planes under their jurisdictions.
And last night we unanimously decided to adopt the FAA's lower limit as our own.
But since hang gliders are a relative bitch to control AND certified to withstand higher loadings...
SHOULDN'T WE BE MOVING THE WEAK LINK RATINGS FOR THESE ORANGES EVEN FARTHER IN THE DIRECTION I AM RECOMMENDING?
Now, back out for some more air...
Brian,
Three is fine, One and Two are not exactly what I'm saying. The rollout and steady state tensions are reasonably low and not that far apart but, yeah, I think that's plenty enough to do it. I'd feel more comfortable saying that we need a .8 G minimum and that minimum will lock out the asses of you and the horse you rode in on.
Here's what I think is going on with respect to conventional weak links - to answer your question with my best guess.
First of all - those are steady state numbers. I'm only interested in low numbers 'cause thermals and position irregularities can take you up to and beyond what the weak link will handle. I was flying one point and extremely poorly (all over the sky) and overshooting pitch inputs most of the time. You can REALLY swing the needle pulling that last trick.
The Greenspot is pretty marginal to begin with. And two knots are involved. A Fisherman's Knot joins the ends and the resultant loop is installed at the eye of the bridle with a Double Lark's Head.
Knots involve rather sharp bends in the line and, under loading, the fibers on the outside of the bend are subjected to more stress than those on the inside.
I think that what's happening is that the weak link is degrading in the course of the tow. You lose some outside fibers when you start to roll and little surges and corrections keep snapping away until... SHIT!
That's the best I've got.
This just in from Portugal...
>
Subj: Re: [Tow] Re: Bridles and Releases
Date: 2007 May 22 Tuesday 07:36:16
From: marco_vento ~~ at ~~ yahoo.com
To: skysailingtowing ~~ at ~~ yahoogroups.com
Tad (is this your name?):
We have been using the TOST weak links in association with either KOCH double release (for dolly launch and for foot launch) or MOYES release (for dolly launch or launch on wheels). The great point is the reliability and precision of these weak links. The weak side is the mass, but the pilot side, when the link breaks, is lighter - the protection box keeps attatched to the cable when the link breaks.
We are quite happy with it, although they are expensive, no false breaks occur anymore. The links are available in a wide range of calibrated break loads as well.
Please send us photos and info on your weak links - we are very much interested in it. Please also inform us how we could acquire some samples.
By the way, all my friends call me Vento - it's my family name but it means wind. Quite appropriate, isn't it? Please call me like that as weel:-)
Greetings
Vento
<
Too bad ya hafta hit the western edge of Eurasia to find a pocket of enlightenment relatively free of the fundamentalist nut cases striving to make sure we never crawl out of the dark ages.
Chris,
I'm not the least bit surprised that you have no clue. Lemme tell you what I told Marc a few posts ago. You have yet to request the documentation I first offered to make available to anyone on the list a couple of weeks shy of two years ago. It's loaded with data.
And, oh yeah Chris, what's the data on the stuff you're currently using?
My points are (listen carefully now)...
1. One size does not fit all (Marc), especially if that size is off the bottom end of the reliability range.
2. We can use high quality weak links in the middle of the safety range and totally eliminate any weak link break which does not involve a pilot who has really fucked up IF we don't continue to behave as a large herd of stupid sheep (fat chance).
With respect to sailplanes...
Last fall I consulted with a sailplane pilot who is also an AT release designer and learned that sail planes are, as you speculate, no brainers to control on tow.
First of all, the upper weak link limits are not mine. They are set by the FAA and the USHGA Towing Committee to cover the planes under their jurisdictions.
And last night we unanimously decided to adopt the FAA's lower limit as our own.
But since hang gliders are a relative bitch to control AND certified to withstand higher loadings...
SHOULDN'T WE BE MOVING THE WEAK LINK RATINGS FOR THESE ORANGES EVEN FARTHER IN THE DIRECTION I AM RECOMMENDING?
Now, back out for some more air...
Brian,
Three is fine, One and Two are not exactly what I'm saying. The rollout and steady state tensions are reasonably low and not that far apart but, yeah, I think that's plenty enough to do it. I'd feel more comfortable saying that we need a .8 G minimum and that minimum will lock out the asses of you and the horse you rode in on.
Here's what I think is going on with respect to conventional weak links - to answer your question with my best guess.
First of all - those are steady state numbers. I'm only interested in low numbers 'cause thermals and position irregularities can take you up to and beyond what the weak link will handle. I was flying one point and extremely poorly (all over the sky) and overshooting pitch inputs most of the time. You can REALLY swing the needle pulling that last trick.
The Greenspot is pretty marginal to begin with. And two knots are involved. A Fisherman's Knot joins the ends and the resultant loop is installed at the eye of the bridle with a Double Lark's Head.
Knots involve rather sharp bends in the line and, under loading, the fibers on the outside of the bend are subjected to more stress than those on the inside.
I think that what's happening is that the weak link is degrading in the course of the tow. You lose some outside fibers when you start to roll and little surges and corrections keep snapping away until... SHIT!
That's the best I've got.
This just in from Portugal...
>
Subj: Re: [Tow] Re: Bridles and Releases
Date: 2007 May 22 Tuesday 07:36:16
From: marco_vento ~~ at ~~ yahoo.com
To: skysailingtowing ~~ at ~~ yahoogroups.com
Tad (is this your name?):
We have been using the TOST weak links in association with either KOCH double release (for dolly launch and for foot launch) or MOYES release (for dolly launch or launch on wheels). The great point is the reliability and precision of these weak links. The weak side is the mass, but the pilot side, when the link breaks, is lighter - the protection box keeps attatched to the cable when the link breaks.
We are quite happy with it, although they are expensive, no false breaks occur anymore. The links are available in a wide range of calibrated break loads as well.
Please send us photos and info on your weak links - we are very much interested in it. Please also inform us how we could acquire some samples.
By the way, all my friends call me Vento - it's my family name but it means wind. Quite appropriate, isn't it? Please call me like that as weel:-)
Greetings
Vento
<
Too bad ya hafta hit the western edge of Eurasia to find a pocket of enlightenment relatively free of the fundamentalist nut cases striving to make sure we never crawl out of the dark ages.
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Hellooo? tap tap tap This thing on? cricketchirp cricketchirp cricketchirp
OK, nobody's listening anymore but just for the record...
Here's something Kevin wrote a year and a half ago when he was under the impression that I was defending a release that was inherently prone to premature release (but was, in fact, improperly adjusted).
>
One pilot in the Texas Open had three premature releases in a row with glider damage on all three and different degrees of pilot injury. I myself have had a low level release that caused minor injury.
When you are discussing the acceptable risk of a premature release.....take the blinders off man. It is a real risk that should be minimized and not taken lightly.
<
Now I'm guessing that even a curved pin barrel doesn't suck enough to be responsible for all that carnage so... Lessee, what else could... Oh, yeah.
So now that we have an easy, obvious solution dumped in our laps what should we do? Grab the pitch forks and torches and head for the infidel.
After screaming for "empirical data with proven and qualitative results" Chris has stormed out of the room and slammed the door behind him. And he now has absolutely no more interest in that very data I've had available years now than he ever has or will.
That data now includes reports on the results of 179 tests of weak links of various flavors and configurations, most of which took an hour or two to set up.
But hey, Chris is a Great Pilot and thus already knows everything worth knowing. And the most important thing is that it's not worth even considering unless everybody's doing it that way already.
Marc will not have demonstrably inferior and dangerous equipment pried from his cold dead fingers until the good stuff "passes muster". You could show him in a heartbeat performance tests which would instantly get the "Case Closed" stamp but what he really means is also, "What are the rest of the sheep doing?"
So he retreats from his promise to "be the first to adapt when and if it passes muster". Now he's gonna be the second to adopt it after it passes the muster of a tug pilot.
A TUG PILOT! Jim is a "very experienced commercial aerotow tug pilot" whose ability to evaluate these systems is also limited to the sheep thing. I know several "very experienced commercial aerotow tug pilots" who have absolutely no interest in or understanding of the stuff that goes on the glider.
With a brain half the size of that of a Turkey Vulture you've got a thousand times the processing power to fly a lot more superbly than any of us ever will at either end of the tow line.
And just what does aerotowing have to do with anything?
Too bad Les isn't around any more. And try running my stuff by Campbell.
Tow park operators? Steve Wendt is a tow park operator. The reason Holly didn't have a weak link when she slammed into the ground was because Steve couldn't have been less interested in the technology I had made a trip to share with him eight months prior.
Marc, it's a freakin' WEAK LINK. Only one of two things can happen.
If it breaks for no reason you're now worse off than the One Size Fits All Miracle Links with which you're currently so enamored.
If you think that a stitch of dental floss holds triple digits, rather than something in the ballpark of 18 pounds, so what? You're a superb tow pilot with the most reliable release system on the planet and you're totally confident that you can get off before you lock out. Besides, you've got a weak link at the other end of the tow line so the worst that could happen would be that you get stuck with the rope.
So exactly what is it that so frightens you?
Take a hint from Vento. He's a pilot, so he knows everything already, but also a mechanical engineer, so he doesn't. He's the only other hang glider person I know of anywhere using a quality weak link system. And, of course, he has totally eliminated premature failures from his operation.
OK, nobody's listening anymore but just for the record...
Here's something Kevin wrote a year and a half ago when he was under the impression that I was defending a release that was inherently prone to premature release (but was, in fact, improperly adjusted).
>
One pilot in the Texas Open had three premature releases in a row with glider damage on all three and different degrees of pilot injury. I myself have had a low level release that caused minor injury.
When you are discussing the acceptable risk of a premature release.....take the blinders off man. It is a real risk that should be minimized and not taken lightly.
<
Now I'm guessing that even a curved pin barrel doesn't suck enough to be responsible for all that carnage so... Lessee, what else could... Oh, yeah.
So now that we have an easy, obvious solution dumped in our laps what should we do? Grab the pitch forks and torches and head for the infidel.
After screaming for "empirical data with proven and qualitative results" Chris has stormed out of the room and slammed the door behind him. And he now has absolutely no more interest in that very data I've had available years now than he ever has or will.
That data now includes reports on the results of 179 tests of weak links of various flavors and configurations, most of which took an hour or two to set up.
But hey, Chris is a Great Pilot and thus already knows everything worth knowing. And the most important thing is that it's not worth even considering unless everybody's doing it that way already.
Marc will not have demonstrably inferior and dangerous equipment pried from his cold dead fingers until the good stuff "passes muster". You could show him in a heartbeat performance tests which would instantly get the "Case Closed" stamp but what he really means is also, "What are the rest of the sheep doing?"
So he retreats from his promise to "be the first to adapt when and if it passes muster". Now he's gonna be the second to adopt it after it passes the muster of a tug pilot.
A TUG PILOT! Jim is a "very experienced commercial aerotow tug pilot" whose ability to evaluate these systems is also limited to the sheep thing. I know several "very experienced commercial aerotow tug pilots" who have absolutely no interest in or understanding of the stuff that goes on the glider.
With a brain half the size of that of a Turkey Vulture you've got a thousand times the processing power to fly a lot more superbly than any of us ever will at either end of the tow line.
And just what does aerotowing have to do with anything?
Too bad Les isn't around any more. And try running my stuff by Campbell.
Tow park operators? Steve Wendt is a tow park operator. The reason Holly didn't have a weak link when she slammed into the ground was because Steve couldn't have been less interested in the technology I had made a trip to share with him eight months prior.
Marc, it's a freakin' WEAK LINK. Only one of two things can happen.
If it breaks for no reason you're now worse off than the One Size Fits All Miracle Links with which you're currently so enamored.
If you think that a stitch of dental floss holds triple digits, rather than something in the ballpark of 18 pounds, so what? You're a superb tow pilot with the most reliable release system on the planet and you're totally confident that you can get off before you lock out. Besides, you've got a weak link at the other end of the tow line so the worst that could happen would be that you get stuck with the rope.
So exactly what is it that so frightens you?
Take a hint from Vento. He's a pilot, so he knows everything already, but also a mechanical engineer, so he doesn't. He's the only other hang glider person I know of anywhere using a quality weak link system. And, of course, he has totally eliminated premature failures from his operation.
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Danny Brotto
- Posts: 708
- Joined: Mon Feb 14, 2005 9:29 pm
Less pull...
Some things to think about…
Depending on set-up, the weak link does not experience the full load provided by the line to the tug. In a bridle like I use (only towing off the shoulders) the load is split between the 2 bridle connect points (where they attach to the harness.) So if the tug pulls at 100 lbs, the weak link only sees only a portion of those pounds; somewhere between 50 and 100 lbs. The exact amount can be calculated based on the span of the harness connect points and the length of the bridle; it’s a 2-D statics problem that a first year mechanical engineer should be able to solve. The short of it however is that the weak link experiences less load than the pull force being presented to the glider. In practice, a weak kinl is not as weak as the simple straight-line breaking strength.
In the more traditional 3 point bridle (harness shoulders and keel connection) the load is shared among 3 points. This is a little more complicated 3D static problem but the point is again that the weak link experiences less load than the pull force presented to the glider.
We set gliders with strong tow pitch pressures up with a keel-forward bridle connect position. While can alleviates pitch tow forces on the pilot to almost nonexistent, it concentrates pressures to the keel/release and onto the weak-link assembly. I would fully expect that gliders set up with 3 point bridles for light tow force pitch pressure to break weak links more readily than the norm.
With the various tow bridle set-ups, a consistent “calibrated” location for a weak-link is in the tow line. The problem here is that we would see weak breakage as the tow rope caught things dragging thru the grass and what not. And then there’s the additional variable of the tow line material. Spectra does not stretch much and does not have much “give”. This presents a different dynamic load than polypro that yields with stretch.
Danny Brotto
Depending on set-up, the weak link does not experience the full load provided by the line to the tug. In a bridle like I use (only towing off the shoulders) the load is split between the 2 bridle connect points (where they attach to the harness.) So if the tug pulls at 100 lbs, the weak link only sees only a portion of those pounds; somewhere between 50 and 100 lbs. The exact amount can be calculated based on the span of the harness connect points and the length of the bridle; it’s a 2-D statics problem that a first year mechanical engineer should be able to solve. The short of it however is that the weak link experiences less load than the pull force being presented to the glider. In practice, a weak kinl is not as weak as the simple straight-line breaking strength.
In the more traditional 3 point bridle (harness shoulders and keel connection) the load is shared among 3 points. This is a little more complicated 3D static problem but the point is again that the weak link experiences less load than the pull force presented to the glider.
We set gliders with strong tow pitch pressures up with a keel-forward bridle connect position. While can alleviates pitch tow forces on the pilot to almost nonexistent, it concentrates pressures to the keel/release and onto the weak-link assembly. I would fully expect that gliders set up with 3 point bridles for light tow force pitch pressure to break weak links more readily than the norm.
With the various tow bridle set-ups, a consistent “calibrated” location for a weak-link is in the tow line. The problem here is that we would see weak breakage as the tow rope caught things dragging thru the grass and what not. And then there’s the additional variable of the tow line material. Spectra does not stretch much and does not have much “give”. This presents a different dynamic load than polypro that yields with stretch.
Danny Brotto
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Flying Lobster
- Posts: 1042
- Joined: Fri Feb 25, 2005 4:17 pm
Excellent points, Danny. We tow with an elastic polypro system in Maine--which I personally don't like cause I hate the "rubber band effect" (especially on tandems)--but others like the "forgiving nature" of the energy absorbtion.
There's yet a third variable missing from the discussion so far which I think is crucial and gets to the core of this discussion.
That is the drag of the glider itself through the air, which, depending upon many variables, can rapidly increase or decrease the pressures on the tow system.
And I say tow system--because I don't believe that you can look at this problem through one of isolation of just one component and expect that adjusting that one component can adjust for failings in other aspects of the system.
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.
I'm hardly an expert on towing and I tend to do my fare share of wandering around under tow, and occassionally break a weaklink (less than a dozen, ground towing since 1989 and aerotowing since 1996) when I just can't keep things in line when going through an especially strong thermal--which is just as well since I probably should have released anyway to work it--but how often do we find ourselves hanging on to the bitter end of the tow even though the tug pilot has dragged us through the core several times??
I've towed at alot of different airtow parks--and I see alot of pilots do things that contribute to marginalizing the safety of their tows beyond just the string and bridle they are attached to. Proper setup of the gear, attachment points, and angle of the harness can make a big difference in the pilot's ability to make smooth control imputs while under tow.
I see alot of gliders, mostly high performance ones, take off with their AOA set too high in the dolly. This encourages an early liftoff before safe airspeed and increases drag and the likelyhood of an unintended wing up early on. In some cases pilots simply let the glider go off the cart as soon as it starts lifting, rather than holding on while building airspeed and adjusting a lower AOA. The extra speed will increase stability and control, as well as allow the towed glider to rise up to a safe "holding" altitude to let the tug rise up to the same level and at the same time reduce line pressure.
Things happen so fast in the first few seconds of a tow that I'm not sure the average pilot could respond with the correct decision fast enough to take away the necessity of a weaklink--one that might occcassionally break seemingly unpredicatably too early.
My opinion is that if you feel that somehow the system is at fault for repeated weaklink breaks or other mishaps during your tows--then a reassessment of all the equipment and processes--including the most important one--your brain--is in order.
marc
Disclaimer: these are just my opinions based on my experience and observations--always ask your professional tow operator what is best for you given your equipment, experience and conditions.
There's yet a third variable missing from the discussion so far which I think is crucial and gets to the core of this discussion.
That is the drag of the glider itself through the air, which, depending upon many variables, can rapidly increase or decrease the pressures on the tow system.
And I say tow system--because I don't believe that you can look at this problem through one of isolation of just one component and expect that adjusting that one component can adjust for failings in other aspects of the system.
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.
I'm hardly an expert on towing and I tend to do my fare share of wandering around under tow, and occassionally break a weaklink (less than a dozen, ground towing since 1989 and aerotowing since 1996) when I just can't keep things in line when going through an especially strong thermal--which is just as well since I probably should have released anyway to work it--but how often do we find ourselves hanging on to the bitter end of the tow even though the tug pilot has dragged us through the core several times??
I've towed at alot of different airtow parks--and I see alot of pilots do things that contribute to marginalizing the safety of their tows beyond just the string and bridle they are attached to. Proper setup of the gear, attachment points, and angle of the harness can make a big difference in the pilot's ability to make smooth control imputs while under tow.
I see alot of gliders, mostly high performance ones, take off with their AOA set too high in the dolly. This encourages an early liftoff before safe airspeed and increases drag and the likelyhood of an unintended wing up early on. In some cases pilots simply let the glider go off the cart as soon as it starts lifting, rather than holding on while building airspeed and adjusting a lower AOA. The extra speed will increase stability and control, as well as allow the towed glider to rise up to a safe "holding" altitude to let the tug rise up to the same level and at the same time reduce line pressure.
Things happen so fast in the first few seconds of a tow that I'm not sure the average pilot could respond with the correct decision fast enough to take away the necessity of a weaklink--one that might occcassionally break seemingly unpredicatably too early.
My opinion is that if you feel that somehow the system is at fault for repeated weaklink breaks or other mishaps during your tows--then a reassessment of all the equipment and processes--including the most important one--your brain--is in order.
marc
Disclaimer: these are just my opinions based on my experience and observations--always ask your professional tow operator what is best for you given your equipment, experience and conditions.
Great Googly-moo!
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Thanks Danny,
Since the shoulder attachment points are so close together (about nine inches) and the bridles that span them are invariably too long, I cheat a little and just divide by two. For what I'm calling a two point bridle (pilot and glider) the attachment points are, by definition, widely separated, I recommend and assume a bridle length which yields a 60 degree apex angle. I divide by two, blow the dust off a little trig, and multiply each end by 1.15.
I am strongly recommending a weak link which goes between the bridle and the tow line. In the both the Tost and my weak link the critical element is isolated and protected. I'm hoping mine will be able to withstand a virtually unlimited number of landings in the gentle environment of the Ridgely strip.
It's rating will not degrade until/unless the base material is badly worn and I'll be disappointed if it doesn't withstand hundreds of cycles.
If I understood Tom Lanning right, the Australians use a high stretch tow line and a very low rated weak link. He says it takes some getting used to but definitely has some merits worth considering. I think I'll stay with Spectra 'cause I can't imagine the alternative does anything for one's fuel economy.
Marc,
More power to Larry but...
Let's define him as 250 pounds and towing off the shoulders. Put a loop of Greenspot on one end of his Spectra bridle and he's got a 1.12 G weak link.
I'm 310 pounds. Put an identical loop on the top end of my point bridle and I've got a 0.79 G weak link - just off the bottom end.
If you're sitting pretty straight behind the tug in glassy air with a brand new weak link and the thing pops for no reason whatsoever then skill has nothing to do with it. This happens all the time. And world class pilots rain out of the sky at competitions all the time. This happens 'cause their weak links are cheap understrength crap, not because they're deficient in the skill department.
You have selected a G rating for yourself. You have selected it on the sole basis of the material being what everybody else uses regardless of his weight. You tell me what you weigh, in what configuration you're towing, and what kind of bridle (material and material diameter) and I'll tell you what that rating is (when your string is very new, anyway).
Mike Haas, the subject of the accident report I quoted, assuming he was within the hook-in range of his glider, was using a weak link of between 1.11 and 0.79 Gs, i.e., at the low end at best and a little off the low end of the safe range at worst.
HIS RELATIVELY FLIMSY WEAK LINK DIDN'T AND COULDN'T HELP HIM.
You're still thinking of the weak link as an emergency release. It's not! It can't be! You need to reread the link Danny referenced. (Don't worry - it took me years to understand this.)
The only emergency releases that can be counted on are the ones controlled by the pilot (odd how Chris got so furious when we were agreeing on that point). Shit never happens so fast that the pilot can't react faster than the weak link. If the pilot can't make a decision faster than the weak link can kick in he shouldn't connect to the tow line. If he does and shit happens... Shit happens.
I have been flying with a high quality 1.12 G weak link (hmmm... that's exactly what my hypothetical Larry uses) since last season. I'd go a lot higher but the one at the tug end ain't that good. It feels so much better being confident that I'm not on the ragged bottom edge anymore.
>
Subj: Re: [Tow] Re: Bridles and Releases
Date: 2007 May 24 Thursday 12:19:17
From: marco_vento@...
To: skysailingtowing@yahoogroups.com
Dear Tad:
I've seen the photos, quite clever I might say!
If you want to give a look at our operation see:
http://www.youtube.com/watch?v=K72Ql7Lnb1Q
We use 1500 N and 2000 Newton weak-links. I am very interested in testing your links. Could you send some (let's say 2 of each?) to my adress (work adress):
M. A. Vento
Linde Sogas
Est. Nacional num. 1 km 38,4 Cheganças
Alenquer - Portugal
2580-381
Please tell me the costs and how could I pay you. (Bank transfer, credit card, ??)
Best regards
Vento
<
Since the shoulder attachment points are so close together (about nine inches) and the bridles that span them are invariably too long, I cheat a little and just divide by two. For what I'm calling a two point bridle (pilot and glider) the attachment points are, by definition, widely separated, I recommend and assume a bridle length which yields a 60 degree apex angle. I divide by two, blow the dust off a little trig, and multiply each end by 1.15.
I am strongly recommending a weak link which goes between the bridle and the tow line. In the both the Tost and my weak link the critical element is isolated and protected. I'm hoping mine will be able to withstand a virtually unlimited number of landings in the gentle environment of the Ridgely strip.
It's rating will not degrade until/unless the base material is badly worn and I'll be disappointed if it doesn't withstand hundreds of cycles.
If I understood Tom Lanning right, the Australians use a high stretch tow line and a very low rated weak link. He says it takes some getting used to but definitely has some merits worth considering. I think I'll stay with Spectra 'cause I can't imagine the alternative does anything for one's fuel economy.
Marc,
More power to Larry but...
Let's define him as 250 pounds and towing off the shoulders. Put a loop of Greenspot on one end of his Spectra bridle and he's got a 1.12 G weak link.
I'm 310 pounds. Put an identical loop on the top end of my point bridle and I've got a 0.79 G weak link - just off the bottom end.
If you're sitting pretty straight behind the tug in glassy air with a brand new weak link and the thing pops for no reason whatsoever then skill has nothing to do with it. This happens all the time. And world class pilots rain out of the sky at competitions all the time. This happens 'cause their weak links are cheap understrength crap, not because they're deficient in the skill department.
You have selected a G rating for yourself. You have selected it on the sole basis of the material being what everybody else uses regardless of his weight. You tell me what you weigh, in what configuration you're towing, and what kind of bridle (material and material diameter) and I'll tell you what that rating is (when your string is very new, anyway).
Mike Haas, the subject of the accident report I quoted, assuming he was within the hook-in range of his glider, was using a weak link of between 1.11 and 0.79 Gs, i.e., at the low end at best and a little off the low end of the safe range at worst.
HIS RELATIVELY FLIMSY WEAK LINK DIDN'T AND COULDN'T HELP HIM.
You're still thinking of the weak link as an emergency release. It's not! It can't be! You need to reread the link Danny referenced. (Don't worry - it took me years to understand this.)
The only emergency releases that can be counted on are the ones controlled by the pilot (odd how Chris got so furious when we were agreeing on that point). Shit never happens so fast that the pilot can't react faster than the weak link. If the pilot can't make a decision faster than the weak link can kick in he shouldn't connect to the tow line. If he does and shit happens... Shit happens.
I have been flying with a high quality 1.12 G weak link (hmmm... that's exactly what my hypothetical Larry uses) since last season. I'd go a lot higher but the one at the tug end ain't that good. It feels so much better being confident that I'm not on the ragged bottom edge anymore.
>
Subj: Re: [Tow] Re: Bridles and Releases
Date: 2007 May 24 Thursday 12:19:17
From: marco_vento@...
To: skysailingtowing@yahoogroups.com
Dear Tad:
I've seen the photos, quite clever I might say!
If you want to give a look at our operation see:
http://www.youtube.com/watch?v=K72Ql7Lnb1Q
We use 1500 N and 2000 Newton weak-links. I am very interested in testing your links. Could you send some (let's say 2 of each?) to my adress (work adress):
M. A. Vento
Linde Sogas
Est. Nacional num. 1 km 38,4 Cheganças
Alenquer - Portugal
2580-381
Please tell me the costs and how could I pay you. (Bank transfer, credit card, ??)
Best regards
Vento
<
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
P.S. Marc, just as you have arbitrarily determined that you're gonna tow at X.XX Gs, Hypothetical Larry will be at 1.12, and I'm gonna be dumped off the bottom of the scale, you've also put a new student at the bottom end of a Falcon 140 at 1.50.
So this isn't really about keeping everybody safe by staying within a hair's breadth of involuntarily popping off tow, is it?
So this isn't really about keeping everybody safe by staying within a hair's breadth of involuntarily popping off tow, is it?
here is some raw statistics: I am about 215, loaded up harness 40 and fly a glider that weighs 85, 340 pounds total. I use the same weak link material as every body else, towing off of the shoulders with a weak link on both sides, equaling four starnds.
I break a weak link about once every two years. a little frayed is better in my way of thinking because I like my weak links weak.
If you are in the moderate range and breaking weak links all of the time, I am sorr friend but the evidence would point to technique, not inferior link material. If you are breaking these all of the time, you probably owe your health and safety to the system thay you may feel is failing.
Here is a concept:
When you are preparing to tow, sit on the cart on the runway ready in the position you are going to begin your role in. Now instruct the tug pilot to give you nothing less that full throttle. tell the person launching (who is really here to check your gear and communicate to the tug) not to push you into the role. Now the weak link will take its highest load during the flight and you are barely rolling on terra firma.
If it breaks you are safe. Just push out if you are rolling faster than you like. If it doesn't break than you are likely not to load up the link any more during the entire flight.
Actually I like the weak link a little frayed. And all of us should be ready for the weak link break during every second of every tow. Its part of the launch.
I break a weak link about once every two years. a little frayed is better in my way of thinking because I like my weak links weak.
If you are in the moderate range and breaking weak links all of the time, I am sorr friend but the evidence would point to technique, not inferior link material. If you are breaking these all of the time, you probably owe your health and safety to the system thay you may feel is failing.
Here is a concept:
When you are preparing to tow, sit on the cart on the runway ready in the position you are going to begin your role in. Now instruct the tug pilot to give you nothing less that full throttle. tell the person launching (who is really here to check your gear and communicate to the tug) not to push you into the role. Now the weak link will take its highest load during the flight and you are barely rolling on terra firma.
If it breaks you are safe. Just push out if you are rolling faster than you like. If it doesn't break than you are likely not to load up the link any more during the entire flight.
Actually I like the weak link a little frayed. And all of us should be ready for the weak link break during every second of every tow. Its part of the launch.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Semi recovered from a punishing but rewarding weekend. Great day at Ridgely Saturday - even I could stay up long enough to get hypothermic and nauseous. Next two days were eaten up by a distant wedding and a lot of driving. Apologies to all my adoring fans for the prolonged absence.
Hi John,
The respect I have for anyone with enough brains and independence to say, "There's gotta be a better way of doing this." and start snooping around a West Marine store is equaled only by my contempt for folk whose immutable engineering standard is, "This is the way everybody's always done it." Thus the following flame pains me a bit, but...
For starters, the fact that you've got weak links on both ends of your one point bridle is not relevant to the discussion. It doesn't hurt anything but, unless your bridle is excessively long (by which I mean anything over seven inches), it isn't helping anything either. What's pertinent to this discussion is that you've got one end of your bridle retained by two strands.
One can't tell from the data you've presented that you've ever actually made it up to twenty feet before your weak link pops.
OK, I'm assuming that you tow a lot more frequently than once every two years and that what you meant was that the overwhelming proportion of your tows are successful? But you should be having zero breaks in a two year period no matter how much you tow. I'm taking a wild guess that that one average break does nothing to enhance your safety?
Also, when - not if, but when - that weak link gives up the ghost I want you to pay for the full tow and go to the back of the line so you're encouraged to use a better system and won't keep the next twenty gliders waiting.
I myself have had 224 tows of any kind dating back to 1980/11/14. Of those my ascent was limited by a dozen weak link breaks. Two of those were consequences of lockouts at altitude where safety wasn't much of an issue. In both cases I elected to allow the break - I could and should have released but had neither been instructed nor figured out that that was the proper course of action. (It is not known whether either of those lockouts was preventable).
So now we're down to ten relevant breaks - all of which were completely unnecessary and undesired. All of of those constituted pains in the ass of various degrees and at least one cost me a really good flying day.
Last season I started developing the concept of stitching based weak links and incorporated it in my bridles. I ain't never gonna have no more weak link breaks.
I didn't start this thread 'cause I was, am, or will be "breaking these all of the time". I'm writing this 'cause everyone else is. As a consequence my lift ticket is too expensive, the wait for a cart is too long, and my flight park is operating inefficiently. To date I owe NOTHING to weak links - the "standard" version owes me big time.
In all of my research to date I know of ZERO weak link breaks which have prevented AT accidents and challenge everyone to provide a blemish to that record.
When I take over as Supreme Dictator of Planet Earth, the first thing I'm gonna do (after, of course, summarily executing all the single occupancy Hummer drivers) is mandate a 0.8 G lower limit for weak links (I'll probably raise that number later). You're struggling to hold onto the bottom end with new weak links and the fuzz is definitely gonna put you out of specs - so be forewarned.
I never said that ability to survive the roll qualifies a weak link for any part of the tow. It most assuredly does not. I need something slightly south of 175 pounds to get me - 310 pounds - moving and I sure don't want to be hovering around that figure. I need 248 pounds to get to the bottom of specs.
But, for arguments sake, let's say that a fuzzy loop of 130 pound Cortland is the ideal weak link for you. Are you gonna give a new loop of the same string to a 162 pound Falcon 140? Like Marc does?
Finally, how 'bout this... Lose your parachute pins and tweak your velcro so you automatically deploy when you hit three Gs positive. It's analogous. Like the idea?
I'm the freakin' pilot. I don't want some goddam lousy piece of shoestring telling me when it's time to get off tow. I will be the one to make that decision.
Hope you will be showing up for the ECC again this year. If you do, could you bring that side pull snap shackle release you developed? I'd like to see and play with it 'cause I think it would be quite compatible with the form of the shear link I'm using in conjunction with my own rig. A spinnaker shackle doesn't cut it, figuratively, 'cause it does, literally.
Although I couldn't disagree with your positions more I really do appreciate your positive contributions to the discussion.
Hi John,
The respect I have for anyone with enough brains and independence to say, "There's gotta be a better way of doing this." and start snooping around a West Marine store is equaled only by my contempt for folk whose immutable engineering standard is, "This is the way everybody's always done it." Thus the following flame pains me a bit, but...
For starters, the fact that you've got weak links on both ends of your one point bridle is not relevant to the discussion. It doesn't hurt anything but, unless your bridle is excessively long (by which I mean anything over seven inches), it isn't helping anything either. What's pertinent to this discussion is that you've got one end of your bridle retained by two strands.
One can't tell from the data you've presented that you've ever actually made it up to twenty feet before your weak link pops.
OK, I'm assuming that you tow a lot more frequently than once every two years and that what you meant was that the overwhelming proportion of your tows are successful? But you should be having zero breaks in a two year period no matter how much you tow. I'm taking a wild guess that that one average break does nothing to enhance your safety?
Also, when - not if, but when - that weak link gives up the ghost I want you to pay for the full tow and go to the back of the line so you're encouraged to use a better system and won't keep the next twenty gliders waiting.
I myself have had 224 tows of any kind dating back to 1980/11/14. Of those my ascent was limited by a dozen weak link breaks. Two of those were consequences of lockouts at altitude where safety wasn't much of an issue. In both cases I elected to allow the break - I could and should have released but had neither been instructed nor figured out that that was the proper course of action. (It is not known whether either of those lockouts was preventable).
So now we're down to ten relevant breaks - all of which were completely unnecessary and undesired. All of of those constituted pains in the ass of various degrees and at least one cost me a really good flying day.
Last season I started developing the concept of stitching based weak links and incorporated it in my bridles. I ain't never gonna have no more weak link breaks.
I didn't start this thread 'cause I was, am, or will be "breaking these all of the time". I'm writing this 'cause everyone else is. As a consequence my lift ticket is too expensive, the wait for a cart is too long, and my flight park is operating inefficiently. To date I owe NOTHING to weak links - the "standard" version owes me big time.
In all of my research to date I know of ZERO weak link breaks which have prevented AT accidents and challenge everyone to provide a blemish to that record.
When I take over as Supreme Dictator of Planet Earth, the first thing I'm gonna do (after, of course, summarily executing all the single occupancy Hummer drivers) is mandate a 0.8 G lower limit for weak links (I'll probably raise that number later). You're struggling to hold onto the bottom end with new weak links and the fuzz is definitely gonna put you out of specs - so be forewarned.
I never said that ability to survive the roll qualifies a weak link for any part of the tow. It most assuredly does not. I need something slightly south of 175 pounds to get me - 310 pounds - moving and I sure don't want to be hovering around that figure. I need 248 pounds to get to the bottom of specs.
But, for arguments sake, let's say that a fuzzy loop of 130 pound Cortland is the ideal weak link for you. Are you gonna give a new loop of the same string to a 162 pound Falcon 140? Like Marc does?
Finally, how 'bout this... Lose your parachute pins and tweak your velcro so you automatically deploy when you hit three Gs positive. It's analogous. Like the idea?
I'm the freakin' pilot. I don't want some goddam lousy piece of shoestring telling me when it's time to get off tow. I will be the one to make that decision.
Hope you will be showing up for the ECC again this year. If you do, could you bring that side pull snap shackle release you developed? I'd like to see and play with it 'cause I think it would be quite compatible with the form of the shear link I'm using in conjunction with my own rig. A spinnaker shackle doesn't cut it, figuratively, 'cause it does, literally.
Although I couldn't disagree with your positions more I really do appreciate your positive contributions to the discussion.
You are right about the multitude of gliders that are subjected to the same system, and I can clearly see that one size probably doesn't fit all.
The snap shackle system I built never failed, and never had to be fixed or repaired during the time that I used it. The hardware is designed to release without any sharp or forged edges meeting the line upon release. if you have a spare shackle of that sort, bring it. I probably have a few in my sailing gear...
The release that I made (with the snap shackle), I gave it away to a pilot named Todd. He needed it to learn how to aerotow. The $150 for the Wallaby Ranch style releases hurts the flying budget... BTW the snap shackle is less than half of the cost of the spinnaker shackle, and the snap shackle ($22) is the most costly component of the rig.
I do have a story where a trike pilot towed me at Quest---Weak link worked---Everybody warned me about the trike pilot's style---Really glad to be here.
I'll save the details for the poker table next week.
JC
The snap shackle system I built never failed, and never had to be fixed or repaired during the time that I used it. The hardware is designed to release without any sharp or forged edges meeting the line upon release. if you have a spare shackle of that sort, bring it. I probably have a few in my sailing gear...
The release that I made (with the snap shackle), I gave it away to a pilot named Todd. He needed it to learn how to aerotow. The $150 for the Wallaby Ranch style releases hurts the flying budget... BTW the snap shackle is less than half of the cost of the spinnaker shackle, and the snap shackle ($22) is the most costly component of the rig.
I do have a story where a trike pilot towed me at Quest---Weak link worked---Everybody warned me about the trike pilot's style---Really glad to be here.
I'll save the details for the poker table next week.
JC
-
Flying Lobster
- Posts: 1042
- Joined: Fri Feb 25, 2005 4:17 pm
Tad, I'm truly dismayed at the prospect of you showing up at the ECC's--flying in that in environment is stressful enough without having someone walking around preaching imminent death to someone who aerotows with present systems.
If you don't think you can control your impulse to denigrate others for using something other than what you personally approve of, I'd just as soon not show up.
You gonna be a good and leave it alone during the comp?
marc
If you don't think you can control your impulse to denigrate others for using something other than what you personally approve of, I'd just as soon not show up.
You gonna be a good and leave it alone during the comp?
marc
Great Googly-moo!
-
Kurt Hirrlinger
- Posts: 30
- Joined: Sat Aug 27, 2005 3:18 am
weak links
What situations are the current weak links designed to resolve Is it possible to apply an automatic release to HG
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
And speaking of contempt for folk whose immutable engineering standard is, "This is the way everybody's always done it." - Heeeeere's MARC!!
If you had had education in reading and arithmetic enough to be able to follow this thread you would have understood from Post 1 that it's not about imminent death and what meets my personal approval. It's about getting gliders to altitude reliably on good days and based on accepted aviation standards.
It is indeed unfortunate that when, in an earlier post, you abdicated your "thought" processes to unspecified tug pilots you did not relinquish your posting rights along with them.
Just as Chris, obviously at this point, does not represent the unified voices of all on the list server, you most assuredly do not speak for the mass of the ECC participants - they're not ALL morons.
Equipment I have noted present at competitions past has included spinnaker shackles, twin and straight pin barrel releases, and redundant weak links. Those are all technologies introduced by yours truly. (I'll back off to "independently developed" on the first one if anyone can cite a reference prior to 1994/09/04).
At last year's competition Dennis Pagen said, "I agree." and went up with a pair of my barrels. The current and recently deposed Ridgely XC record holders fly with my design. PK was very happy recently after his maiden tow with the set he acquired from me at the end of last season. I suspect that Bob Lane's design I recently saw referenced in the Oz Report owes something to the secondary bridle assembly I sent down to Kevin a year prior.
Saturday night Sunny stated that the points I've made in this discussion sound solid and declared his intention to start flying with the shear link I provided.
(I hope everyone notices how Marc always slinks back under his rock without responding to questions like "By what standards is the equipment you use proven?")
John,
Yeah, I was afraid I remembered that you said you had given your release away. Believe you had incorporated a Ronstan snap shackle but I can't recall which one. Can you take a look at:
http://www.apsltd.com/Tree/d270000/e267100.asp
and see if you can find a match?
I look forward to the account of the trike tow and will keep an open mind but you gotta convince me that the weak link failure was necessary and would have occurred before I would have hit a vowel in whatever expletive I would have been uttering at the time.
By the way, I can provide you with a weak link of any strength up from the equivalent of a 123 pound loop of string that will maintain its integrity until your tow line tension hits that rating (245 pounds).
Tim (Kurt),
The current weak links are "designed" to pop for no reason whatsoever when you'd much prefer to be continuing up to a workable altitude and hold on to the death when your hands are frozen onto the basetube.
People think they're designing them to prevent lockouts. They're not and can't.
They should be designed as a failsafe to protect the glider up high - only the release can reliably protect the pilot down low.
Yeah, I think an automatic release would be doable but I also think you'd have to incorporate gyros and spend a lot of tow ten packs. As it is we've got people with releases at both ends of the tow line and that should (but, yeah, doesn't always) work.
I think that if you want to spend money the best bang for the buck would be in the development of a computer simulator called "Lockout!" It's the area in which proficiency is most critical and the opportunity to practice is extremely rare.
If you had had education in reading and arithmetic enough to be able to follow this thread you would have understood from Post 1 that it's not about imminent death and what meets my personal approval. It's about getting gliders to altitude reliably on good days and based on accepted aviation standards.
It is indeed unfortunate that when, in an earlier post, you abdicated your "thought" processes to unspecified tug pilots you did not relinquish your posting rights along with them.
Just as Chris, obviously at this point, does not represent the unified voices of all on the list server, you most assuredly do not speak for the mass of the ECC participants - they're not ALL morons.
Equipment I have noted present at competitions past has included spinnaker shackles, twin and straight pin barrel releases, and redundant weak links. Those are all technologies introduced by yours truly. (I'll back off to "independently developed" on the first one if anyone can cite a reference prior to 1994/09/04).
At last year's competition Dennis Pagen said, "I agree." and went up with a pair of my barrels. The current and recently deposed Ridgely XC record holders fly with my design. PK was very happy recently after his maiden tow with the set he acquired from me at the end of last season. I suspect that Bob Lane's design I recently saw referenced in the Oz Report owes something to the secondary bridle assembly I sent down to Kevin a year prior.
Saturday night Sunny stated that the points I've made in this discussion sound solid and declared his intention to start flying with the shear link I provided.
(I hope everyone notices how Marc always slinks back under his rock without responding to questions like "By what standards is the equipment you use proven?")
John,
Yeah, I was afraid I remembered that you said you had given your release away. Believe you had incorporated a Ronstan snap shackle but I can't recall which one. Can you take a look at:
http://www.apsltd.com/Tree/d270000/e267100.asp
and see if you can find a match?
I look forward to the account of the trike tow and will keep an open mind but you gotta convince me that the weak link failure was necessary and would have occurred before I would have hit a vowel in whatever expletive I would have been uttering at the time.
By the way, I can provide you with a weak link of any strength up from the equivalent of a 123 pound loop of string that will maintain its integrity until your tow line tension hits that rating (245 pounds).
Tim (Kurt),
The current weak links are "designed" to pop for no reason whatsoever when you'd much prefer to be continuing up to a workable altitude and hold on to the death when your hands are frozen onto the basetube.
People think they're designing them to prevent lockouts. They're not and can't.
They should be designed as a failsafe to protect the glider up high - only the release can reliably protect the pilot down low.
Yeah, I think an automatic release would be doable but I also think you'd have to incorporate gyros and spend a lot of tow ten packs. As it is we've got people with releases at both ends of the tow line and that should (but, yeah, doesn't always) work.
I think that if you want to spend money the best bang for the buck would be in the development of a computer simulator called "Lockout!" It's the area in which proficiency is most critical and the opportunity to practice is extremely rare.
Wow... this thread is still going?
Hahahahaha... as if this is shocking?
Guys, take all your equations and stuff them. We all know bumbelbees don't fly right?
Any tug pilot will tell you that this is all bunk. Weaklinks don't "protect" you from lockout, but I'll be damned if I listen to someone tell me that they don't break during lockout.
Try to get behind me without a weaklink... try... I will not tow you.
Jim
Hahahahaha... as if this is shocking?
Guys, take all your equations and stuff them. We all know bumbelbees don't fly right?
Any tug pilot will tell you that this is all bunk. Weaklinks don't "protect" you from lockout, but I'll be damned if I listen to someone tell me that they don't break during lockout.
Try to get behind me without a weaklink... try... I will not tow you.
Jim
Thread Advice
Weaklink - a bundle of threads tied in a loop.
Is this thread weak enough?
Here's a reading suggestion for at least some of the folks who have been playing in or reading this thread.
You can decide for yourselves who really needs to read it.
http://tinyurl.com/2ltzsw
Is this thread weak enough?
Here's a reading suggestion for at least some of the folks who have been playing in or reading this thread.
You can decide for yourselves who really needs to read it.
http://tinyurl.com/2ltzsw
Cragin
Douglas.Cragin(AT)iCloud(DOT)com
Weather - https://sites.google.com/site/hgweather/
Flying - http://craginsflightblog.blogspot.com/
Kay's Stuff- http://kayshappenings.blogspot.com/
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It is with great trepidation and against my better judgment that i enter this thread - but since when have I ever listened to my better judgment? In all the discussion about weak links, I think what has gotten lost is the idea of a primary release that can be actuated without removing a hand from the basetube - particularly in a panic situation approaching a lockout. I am quite happy with the one I have with a loop of line that goes around the palm - just slide the hand inboard 1/2 to 1 inch. I have accepted samples of Tad's and Steve's mouth-release prototypes, but confess I have yet to tow with them - primarily because I want the inventor to assist me in rigging it the first time. Also, last year I was still getting used to towing the U2 without a strap-on fin and didn't want any extra novelties. I seem to be pretty solid towing the U2 (finally) and will bring the samples. If I'm not in too much of a hurry during the comp, I'll be willing to try an alternate tow release. - Hugh
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Jim,
People like me have to use equations so that people like you will have something to fly.
I'm quite sure that you know that bumblebees don't fly but the equation crowd figured out that they catch the tip vortices on the backstroke.
The strength and performance of the design of that pair of barrel releases I wasted four hours making for you last fall was verified using equations.
And to waste a little more time (somebody who hasn't bothered to listen the first dozen times is highly unlikely to bother paying attention the thirteenth)...
Weak links do not necessarily break during lockout. Sometimes the glider slams into the ground first. A weak link will always break if the ground doesn't get there first.
I'd like you to provide a single QUOTE from this thread in which ANYONE suggested eliminating a weak link. Something a little more specific than the "You said..." vague accusations of which you and Marc are so fond.
By the way...
The best weak link protected two point gliders you tow are the ones using bridle systems I've designed and assembled. If the bridle wraps at the carabiner after failure of the primary weak link, the secondary at the bottom end blows instantly.
If your Dragonfly weak link pops and the lower bridle component wraps - you're out of ammo (see my first post).
Cragin,
A weak link does not have to and assuredly should not be "a bundle of threads tied in a loop" that you can "NEVER TRUST".
You can't make friends with or influence Jerry Falwell 'cause he don't need no stinking data, evidence, formulae, logic, common sense... He already knows The Truth.
Marc,
Look Marc! An ECC competitor who thinks a safety enhancement might be worth looking into.
Hugh,
In your case (two point) it's not really an alternate - just a supplement.
Since you're still towing in that configuration I'm starting to question my decision to talk you out of going with my full installation.
Look forward to seeing you.
People like me have to use equations so that people like you will have something to fly.
I'm quite sure that you know that bumblebees don't fly but the equation crowd figured out that they catch the tip vortices on the backstroke.
The strength and performance of the design of that pair of barrel releases I wasted four hours making for you last fall was verified using equations.
And to waste a little more time (somebody who hasn't bothered to listen the first dozen times is highly unlikely to bother paying attention the thirteenth)...
Weak links do not necessarily break during lockout. Sometimes the glider slams into the ground first. A weak link will always break if the ground doesn't get there first.
I'd like you to provide a single QUOTE from this thread in which ANYONE suggested eliminating a weak link. Something a little more specific than the "You said..." vague accusations of which you and Marc are so fond.
By the way...
The best weak link protected two point gliders you tow are the ones using bridle systems I've designed and assembled. If the bridle wraps at the carabiner after failure of the primary weak link, the secondary at the bottom end blows instantly.
If your Dragonfly weak link pops and the lower bridle component wraps - you're out of ammo (see my first post).
Cragin,
A weak link does not have to and assuredly should not be "a bundle of threads tied in a loop" that you can "NEVER TRUST".
You can't make friends with or influence Jerry Falwell 'cause he don't need no stinking data, evidence, formulae, logic, common sense... He already knows The Truth.
Marc,
Look Marc! An ECC competitor who thinks a safety enhancement might be worth looking into.
Hugh,
In your case (two point) it's not really an alternate - just a supplement.
Since you're still towing in that configuration I'm starting to question my decision to talk you out of going with my full installation.
Look forward to seeing you.
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Correction -
With respect to the report:
"Yesterday I was LUCKY that my weak link broke on my first launch..."
Although there can be a couple of ways to interpret that passage a very careful reading reveals what Daniel Broxterman meant.
I had assumed that he was about to die but after an inquiry at Ridgely last weekend understood that getting involuntarily deposited back on the ground set him up to take advantage of a later lift cycle. The pop off was due not to the low level lockout onset I had envisioned but rather to some moderate turbulence and shouldn't have happened.
So move that one from the category of "Potentially Catastrophic" to the one which would normally have been "Moderately Annoying".
With respect to the report:
"Yesterday I was LUCKY that my weak link broke on my first launch..."
Although there can be a couple of ways to interpret that passage a very careful reading reveals what Daniel Broxterman meant.
I had assumed that he was about to die but after an inquiry at Ridgely last weekend understood that getting involuntarily deposited back on the ground set him up to take advantage of a later lift cycle. The pop off was due not to the low level lockout onset I had envisioned but rather to some moderate turbulence and shouldn't have happened.
So move that one from the category of "Potentially Catastrophic" to the one which would normally have been "Moderately Annoying".
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theflyingdude
- Posts: 356
- Joined: Thu Jan 06, 2005 11:40 pm
- Location: Cumberland, MD
Tad Eareckson wrote:Correction -
With respect to the report:
"Yesterday I was LUCKY that my weak link broke on my first launch..."
Although there can be a couple of ways to interpret that passage a very careful reading reveals what Daniel Broxterman meant.
I had assumed that he was about to die but after an inquiry at Ridgely last weekend understood that getting involuntarily deposited back on the ground set him up to take advantage of a later lift cycle. The pop off was due not to the low level lockout onset I had envisioned but rather to some moderate turbulence and shouldn't have happened.
So move that one from the category of "Potentially Catastrophic" to the one which would normally have been "Moderately Annoying".
Why don't you give it a rest, Tad. You moved past the "Moderately Annoying" category several posts ago.
jR
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am