From my experience, the Highland tug pilots do their very best to take you to lift. Zach is a master at this. My solution to long waits is to get off tow in the first thermal that I can sustain/climb in and allow the tug to quickly return for the next tow. (Tug pilots have that incevtive to get you to a good thermal quickly.) The next guy in line has never thanked me but the Highland crew has expressed appreciation for this practice.
From my experience, the Highland tandem pilots give instruction in calm conditions only while "rides" may be conducted in "trashier" conditions. With instruction the student is likely actively flying the glider. On rides the tandem pilot is expertly flying the glider. I suspect that the expert tamdem pilot will subject the towline to low G since he knows what's he's doing even in mid-day conditions.
I've never been put out or had to wait too long to get tandems out of the way. When Highland anticipates a busy tandem day, they often post that situation on this forum so as to not put anyone off.
Danny Brotto
Weak link question
Moderator: CHGPA BOD
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
>
I suspect that the expert tamdem pilot will subject the towline to low G since he knows what's he's doing even in mid-day conditions.
<
I don't buy this AT ALL.
For starters this view is flatly contradicted by Jim's post of 2008/11/24 (yeah - for what that's worth).
And like I said before... A freakin' Hang II can be as expert a tow pilot after three or four hops as he or anyone else is ever gonna get. There's not that much to it and there's only so much you can do back there. And most of that is fighting the boredom and remaining focused for the duration.
You take an "expert" tandem pilot, stick him on a bladewing, give him a single loop of Greenspot, throw him into a world class competition - he doesn't get up any better or worse than any other similarly equipped top ranked skygod or Hang III also-ran of like weight.
The ones who DO efficiently get where they wanna go are the anorexics and the folk like Davis who are smart enough to double their weak links.
>
I've never been put out or had to wait too long to get tandems out of the way.
<
If ANYONE who is interested in maxing out his airtime is standing in line during the soaring window he is - by definition - being put out by EVERYTHING in front of him - twice as much when a tug is down (read always).
I don't begrudge the tandems the slots they take 'cause - like I said - they're subsidizing my ride. I do however very much take issue with needless weak link breaks gumming up the works. And ALL of the weak link breaks at Ridgely have been needless.
It totally pisses me off when somebody slaps on a 0.5 or 0.6 G weak link, pops for no reason, and gets back in line in front of me or anyone else.
Again, no complaint about the quality of the tug pilots' thermal sniffing abilities. If there's something brain dead to be found they do great jobs of dropping me in it.
I also get off tow as soon as I think I've got something I can use. I do this to give as much break as possible to the icecaps, Highland Aerosports, and the people in line (in that order).
Here is a complete record of my release AGLs over the past two seasons:
2691
1210
2455
2063
2199
1239
2477
1352
2503
1500
0928
1544
2763
1999
1568
1166
1625
2581
2745
1341
1493
1573
2279
1803
1846
2543
1716
2636
2604
If you do the math you find that I'm giving the aforementioned an average of 554 feet per haul.
And they NEVER have to hook me up twice. They NEVER WILL have to hook me up twice.
And, to date, as a direct result of my efforts there are about a half a dozen other people - including Sunny - they never have to hook up twice.
It's a pretty good bet that I've saved Highland multiples of time, gas, and wear and tear what any runner up can make a claim on. But I'm having a hard time recalling any appreciation expressed.
On the other hand... God help me if I cost an extra five seconds of idle-time 'cause I've made it to the pad having forgotten to push the record button on my GPS.
So I guess it just depends a lot on who you are.
I suspect that the expert tamdem pilot will subject the towline to low G since he knows what's he's doing even in mid-day conditions.
<
I don't buy this AT ALL.
For starters this view is flatly contradicted by Jim's post of 2008/11/24 (yeah - for what that's worth).
And like I said before... A freakin' Hang II can be as expert a tow pilot after three or four hops as he or anyone else is ever gonna get. There's not that much to it and there's only so much you can do back there. And most of that is fighting the boredom and remaining focused for the duration.
You take an "expert" tandem pilot, stick him on a bladewing, give him a single loop of Greenspot, throw him into a world class competition - he doesn't get up any better or worse than any other similarly equipped top ranked skygod or Hang III also-ran of like weight.
The ones who DO efficiently get where they wanna go are the anorexics and the folk like Davis who are smart enough to double their weak links.
>
I've never been put out or had to wait too long to get tandems out of the way.
<
If ANYONE who is interested in maxing out his airtime is standing in line during the soaring window he is - by definition - being put out by EVERYTHING in front of him - twice as much when a tug is down (read always).
I don't begrudge the tandems the slots they take 'cause - like I said - they're subsidizing my ride. I do however very much take issue with needless weak link breaks gumming up the works. And ALL of the weak link breaks at Ridgely have been needless.
It totally pisses me off when somebody slaps on a 0.5 or 0.6 G weak link, pops for no reason, and gets back in line in front of me or anyone else.
Again, no complaint about the quality of the tug pilots' thermal sniffing abilities. If there's something brain dead to be found they do great jobs of dropping me in it.
I also get off tow as soon as I think I've got something I can use. I do this to give as much break as possible to the icecaps, Highland Aerosports, and the people in line (in that order).
Here is a complete record of my release AGLs over the past two seasons:
2691
1210
2455
2063
2199
1239
2477
1352
2503
1500
0928
1544
2763
1999
1568
1166
1625
2581
2745
1341
1493
1573
2279
1803
1846
2543
1716
2636
2604
If you do the math you find that I'm giving the aforementioned an average of 554 feet per haul.
And they NEVER have to hook me up twice. They NEVER WILL have to hook me up twice.
And, to date, as a direct result of my efforts there are about a half a dozen other people - including Sunny - they never have to hook up twice.
It's a pretty good bet that I've saved Highland multiples of time, gas, and wear and tear what any runner up can make a claim on. But I'm having a hard time recalling any appreciation expressed.
On the other hand... God help me if I cost an extra five seconds of idle-time 'cause I've made it to the pad having forgotten to push the record button on my GPS.
So I guess it just depends a lot on who you are.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
>
RedBaron
2008/11/24 01:20:25
Brian, I don't know why you feel us bigger guys need to beef things up. Talked to Glen, he gave me permission to drop his name. He hooks to the tow line at an impressive 350 lb. He had a total of 1(!) unexpected weak link break out of all his tows. He knows nothing of this discussion, so I asked him how he felt about using a stronger weak link. His answer was a straight "NO". Both Glen and I veto you on beefing our weak links up based on our good and safe experience with greenspot.
<
So much bullshit through which to wade, so little time...
>
He had a total of 1(!) unexpected weak link break out of all his tows.
<
No shit. One pop out of ALL of his tows. Given this information we're not entirely sure that he's ever actually gotten off the ground. A good and safe experience with Greenspot indeed.
What we do know is that the 1(!) pop was unexpected so it obviously didn't happen under any particular load or for any particular reason. Our goal should be 0(!) pops over a long flying career. And IF we've fucked up so bad we need one - we should definitely be expecting it.
>
...so I asked him how he felt about using a stronger weak link. His answer was a straight "NO".
<
But of course if you ask ANYONE who doesn't know what he's talking about (which is damn near EVERYONE) that same question - from Glen on down to Ayesha (not Karen) grade his answer will also be a straight "NO" - also based on his good and safe experience with Greenspot (no matter how many downtubes he's bent).
Now let's ask Glen how he feels about using a WEAKER weak link.
His answer will AGAIN be a straight "NO" - again based on his good and safe experience with Greenspot.
And we again ask everyone down to Ayesha grade the same question and we will again get nothing but straight "NOs" based on their good and safe experiences with Greenspot.
Each and every one of them has been told that the single loop of 130 pound Greenspot is the PERFECT 1.00 G weak link that God has fashioned precisely for him. And each and every one of them actually BELIEVES THIS!
UN - BE -LIEV - AB - LY STUPID.
RedBaron
2008/11/24 01:20:25
Brian, I don't know why you feel us bigger guys need to beef things up. Talked to Glen, he gave me permission to drop his name. He hooks to the tow line at an impressive 350 lb. He had a total of 1(!) unexpected weak link break out of all his tows. He knows nothing of this discussion, so I asked him how he felt about using a stronger weak link. His answer was a straight "NO". Both Glen and I veto you on beefing our weak links up based on our good and safe experience with greenspot.
<
So much bullshit through which to wade, so little time...
>
He had a total of 1(!) unexpected weak link break out of all his tows.
<
No shit. One pop out of ALL of his tows. Given this information we're not entirely sure that he's ever actually gotten off the ground. A good and safe experience with Greenspot indeed.
What we do know is that the 1(!) pop was unexpected so it obviously didn't happen under any particular load or for any particular reason. Our goal should be 0(!) pops over a long flying career. And IF we've fucked up so bad we need one - we should definitely be expecting it.
>
...so I asked him how he felt about using a stronger weak link. His answer was a straight "NO".
<
But of course if you ask ANYONE who doesn't know what he's talking about (which is damn near EVERYONE) that same question - from Glen on down to Ayesha (not Karen) grade his answer will also be a straight "NO" - also based on his good and safe experience with Greenspot (no matter how many downtubes he's bent).
Now let's ask Glen how he feels about using a WEAKER weak link.
His answer will AGAIN be a straight "NO" - again based on his good and safe experience with Greenspot.
And we again ask everyone down to Ayesha grade the same question and we will again get nothing but straight "NOs" based on their good and safe experiences with Greenspot.
Each and every one of them has been told that the single loop of 130 pound Greenspot is the PERFECT 1.00 G weak link that God has fashioned precisely for him. And each and every one of them actually BELIEVES THIS!
UN - BE -LIEV - AB - LY STUPID.
-
Flying Lobster
- Posts: 1042
- Joined: Fri Feb 25, 2005 4:17 pm
Re: Weak link question
So Tad--
Given your opposition to greenspot and the obvious (to you) dangers inherent in using it--what does that say about all the aerotow parks and tug pilots that use it or permit it's use? You must feel that they are at least complicitly negligent in it's continuing use, right?
marc
Given your opposition to greenspot and the obvious (to you) dangers inherent in using it--what does that say about all the aerotow parks and tug pilots that use it or permit it's use? You must feel that they are at least complicitly negligent in it's continuing use, right?
marc
Great Googly-moo!
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Marc,
That question is ample evidence that this conversation is way way way out of your league (big surprise). You would do well to sit back, lurk, and try to learn something. But, against my better judgment, giving you the benefit of the doubt, and going back to Billy's First Book of Towing basics...
Weak links are all about G ratings. I haven't got time to fully explain that to you so try to find a grownup to ask.
Little gliders - like Karen - need to use relatively light weak links. She's just fine with a single loop of Greenspot on the end of her two point bridle 'cause that puts her at 1.22 Gs - comfortably in the midrange of all established safety ranges.
However, if some clown gives Glen - who's packing 175 percent of Karen's mass - the SAME weak link, that puts him at 0.70 - which is dangerously short of the bottom end of all established safety ranges.
If Glen were smart enough to double the loop he'd be towing at 0.99 Gs which is still low but something we can probably start living with.
In fact if ANY solo two pointer from 174 pounds up (which, of course, means EVERY solo two pointer) were to double his Greenspot he would be with within the 0.8 to 2.0 range.
But I make better weak links that I can fine tune for individual pilots so I can do a lot better than Greenspot for individuals who don't happen to fit very well into the one or two sizes fit all scheme we've been using. Some of the smarter pilots realize this and have incorporated them.
So I don't oppose Greenspot, per se, but yes - the people who are giving both Karen and Glen single loops are and telling them both that they've got 1 G weak links are, if fact, idiots and grossly negligent with respect to the latter's safety. He's not gonna be able to stay on tow in a situation in which tow tension is the only thing keeping him alive.
That clear enough?
That question is ample evidence that this conversation is way way way out of your league (big surprise). You would do well to sit back, lurk, and try to learn something. But, against my better judgment, giving you the benefit of the doubt, and going back to Billy's First Book of Towing basics...
Weak links are all about G ratings. I haven't got time to fully explain that to you so try to find a grownup to ask.
Little gliders - like Karen - need to use relatively light weak links. She's just fine with a single loop of Greenspot on the end of her two point bridle 'cause that puts her at 1.22 Gs - comfortably in the midrange of all established safety ranges.
However, if some clown gives Glen - who's packing 175 percent of Karen's mass - the SAME weak link, that puts him at 0.70 - which is dangerously short of the bottom end of all established safety ranges.
If Glen were smart enough to double the loop he'd be towing at 0.99 Gs which is still low but something we can probably start living with.
In fact if ANY solo two pointer from 174 pounds up (which, of course, means EVERY solo two pointer) were to double his Greenspot he would be with within the 0.8 to 2.0 range.
But I make better weak links that I can fine tune for individual pilots so I can do a lot better than Greenspot for individuals who don't happen to fit very well into the one or two sizes fit all scheme we've been using. Some of the smarter pilots realize this and have incorporated them.
So I don't oppose Greenspot, per se, but yes - the people who are giving both Karen and Glen single loops are and telling them both that they've got 1 G weak links are, if fact, idiots and grossly negligent with respect to the latter's safety. He's not gonna be able to stay on tow in a situation in which tow tension is the only thing keeping him alive.
That clear enough?
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
(Make that "and are".)
Local one-size-fits-all self proclaimed expert on everything idiot tug pilot on Tost weak links:
>
Plastic links...
"Manufactured by Bob" doesn't meet my criteria.
They are not manufactured to tolerances. They're not "manufactured" at all... They are a material that some guy found consistent enough to feel comfortable about. He cuts holes and tests, but it's still Bob in his backyard. He doesn't make the plastic, so he has no control over the quality of it.
That said, I'd feel a whole lot better about these than Tad's stuff.
<
Tost - Flugzeuggerätebau on Tost weak links:
>
Weak links and accessories
After half a Century we have optimized the format of our weak links. While operating dimensions and price remain the same, there are clear benefits:
Longer service life
Correct load group code and manufacturer's mark
Made of high-quality certified aircraft steel
Clear differentiation from inferior copies
Manufacturing tolerance 5%
Like type-approved equipment, our weak links are also manufactured according to EASA-approved production methods. Each batch is tested on computerized test equipment and the results are documented to guarantee consistent quality and traceability.
Notes
Weak links protect your aircraft against overloading.
Use only the weak links stipulated in your aircraft TCDS or aircraft manual.
Checking the cable preamble is mandatory according to SBO; this includes the inspection of weak links.
Replace the weak link immediately in the case of visible damage.
We recommend that the weak link insert be replaced after 200 Starts - an insert is always cheaper than an aborted launch.
...
We also manufacture weak links for special applications with breaking loads up to 50 kN. These are used for bracing loads on aerials, rigging, offshore, tugs or anchorage of hot-air balloons.
<
>
WEAK LINKS PROTECT YOUR AIRCRAFT AGAINST OVERLOADING.
USE ONLY THE WEAK LINKS STIPULATED IN YOUR AIRCRAFT TCDS OR AIRCRAFT MANUAL.
CHECKING THE CABLE PREAMBLE IS MANDATORY ACCORDING TO SBO; THIS INCLUDES THE INSPECTION OF WEAK LINKS.
REPLACE THE WEAK LINK IMMEDIATELY IN THE CASE OF VISIBLE DAMAGE.
WE RECOMMEND THAT THE WEAK LINK INSERT BE REPLACED AFTER 200 STARTS - AN INSERT IS ALWAYS CHEAPER THAN AN ABORTED LAUNCH.
<
I think I've found a portal to that strange Two Plus Two Equals Four Parallel Universe I previously referenced.
In this Two Plus Two Equals Whatever Lord Jim Says It Equals Universe...
Weak links protect the glider from lockout, compensate for shit releases, and prevent the tug from losing control.
Use the same weak link for ALL gliders.
Why bother scaling the weak link to the glider or inspecting for damage? The weaker it is, the safer it is.
Aborted launches? BFD. There are absolutely no costs whatsoever associated with them.
Scotty, do you think you can get your engines to hold long enough to make it through?
Local one-size-fits-all self proclaimed expert on everything idiot tug pilot on Tost weak links:
>
Plastic links...
"Manufactured by Bob" doesn't meet my criteria.
They are not manufactured to tolerances. They're not "manufactured" at all... They are a material that some guy found consistent enough to feel comfortable about. He cuts holes and tests, but it's still Bob in his backyard. He doesn't make the plastic, so he has no control over the quality of it.
That said, I'd feel a whole lot better about these than Tad's stuff.
<
Tost - Flugzeuggerätebau on Tost weak links:
>
Weak links and accessories
After half a Century we have optimized the format of our weak links. While operating dimensions and price remain the same, there are clear benefits:
Longer service life
Correct load group code and manufacturer's mark
Made of high-quality certified aircraft steel
Clear differentiation from inferior copies
Manufacturing tolerance 5%
Like type-approved equipment, our weak links are also manufactured according to EASA-approved production methods. Each batch is tested on computerized test equipment and the results are documented to guarantee consistent quality and traceability.
Notes
Weak links protect your aircraft against overloading.
Use only the weak links stipulated in your aircraft TCDS or aircraft manual.
Checking the cable preamble is mandatory according to SBO; this includes the inspection of weak links.
Replace the weak link immediately in the case of visible damage.
We recommend that the weak link insert be replaced after 200 Starts - an insert is always cheaper than an aborted launch.
...
We also manufacture weak links for special applications with breaking loads up to 50 kN. These are used for bracing loads on aerials, rigging, offshore, tugs or anchorage of hot-air balloons.
<
>
WEAK LINKS PROTECT YOUR AIRCRAFT AGAINST OVERLOADING.
USE ONLY THE WEAK LINKS STIPULATED IN YOUR AIRCRAFT TCDS OR AIRCRAFT MANUAL.
CHECKING THE CABLE PREAMBLE IS MANDATORY ACCORDING TO SBO; THIS INCLUDES THE INSPECTION OF WEAK LINKS.
REPLACE THE WEAK LINK IMMEDIATELY IN THE CASE OF VISIBLE DAMAGE.
WE RECOMMEND THAT THE WEAK LINK INSERT BE REPLACED AFTER 200 STARTS - AN INSERT IS ALWAYS CHEAPER THAN AN ABORTED LAUNCH.
<
I think I've found a portal to that strange Two Plus Two Equals Four Parallel Universe I previously referenced.
In this Two Plus Two Equals Whatever Lord Jim Says It Equals Universe...
Weak links protect the glider from lockout, compensate for shit releases, and prevent the tug from losing control.
Use the same weak link for ALL gliders.
Why bother scaling the weak link to the glider or inspecting for damage? The weaker it is, the safer it is.
Aborted launches? BFD. There are absolutely no costs whatsoever associated with them.
Scotty, do you think you can get your engines to hold long enough to make it through?
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
>
http://www.sonomawings.com/archive/fl2003/florida.htm
Vince Endter
2003/04/12
There were pilots constantly sinking out and landing back at Quest. I landed and got in line again. The third time I was behind a trike that seemed very under-powered or we were in constant sink. They took me over to the west above a swamp, lake and trees. There was nowhere to land if the weak link broke. I looked at my altimeter and I was at 230'. I had set it for 130 before takeoff. You do the math. We continued to fly over unlandable terrain for a couple of minutes before we started any type of climb.
<
>
jimrooney
BTW, this weaklink as a lifeline comment... any tow pilot that takes you over something you can't get out from should be shot.
<
Maybe. But you can't shoot the guy if you've got alligators on both your arms. 0.75 or 1.40?
http://www.sonomawings.com/archive/fl2003/florida.htm
Vince Endter
2003/04/12
There were pilots constantly sinking out and landing back at Quest. I landed and got in line again. The third time I was behind a trike that seemed very under-powered or we were in constant sink. They took me over to the west above a swamp, lake and trees. There was nowhere to land if the weak link broke. I looked at my altimeter and I was at 230'. I had set it for 130 before takeoff. You do the math. We continued to fly over unlandable terrain for a couple of minutes before we started any type of climb.
<
>
jimrooney
BTW, this weaklink as a lifeline comment... any tow pilot that takes you over something you can't get out from should be shot.
<
Maybe. But you can't shoot the guy if you've got alligators on both your arms. 0.75 or 1.40?
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
If the weather's crappy enough people will read anything.
Weak Link Flavors - Pros and Cons
1. Greenspot - 130 pound
Let's put everyone on two point (pilot and glider) Spectra bridles to simplify things. If you wanna adjust for one point you can go with a bit more weight on a given strength.
Nothing magical about it but it's very strong for its very minimal diameter.
If you use a larger diameter line the Fisherman's Knot with which you form the loop starts getting bulky and that can be problematic when the end of the bridle is trying to clear something. Better to just double the Greenspot.
A single loop on gliders up to the low two hundreds range isn't a bad solution. The direct load it will hold maxes out pretty reliably around 140 pounds (rather than the 260 popularly assumed). And on the light kites it tends not to get stressed out so you can also rely on it not falling way below that figure until it gets chewed up by the spinnaker shackle you shouldn't be using anyway.
On that note - I do have photos of a Tim Hinkel prototype release currently up near the top of the stack at:
http://www.flickr.com/photos/aerotowrelease/
(and, for future reference, filed in the Miscellaneous set). I'm hoping that he will be able to get these things in circulation before too long 'cause they're a much better, safer solution.
A double loop holds to a direct load of around 200 pounds and I recommend you start thinking about it as your glider starts getting much over about 225. At that figure you're in good shape at 1.55 Gs and by 248 pounds you're down to the 1.40 sweet spot.
If you stick with a single beyond the low two hundreds you can still be sure that your high end direct load won't exceed 140 but the low end reliability goes straight to hell. Thus Glen's shiny new hypothetical 0.7 G weak link may very well be down to 0.4 by the time he clears the cart (IF he clears the cart).
2. Tost
http://www.tost.de/
Pros...
The tolerances are very good / excellent.
Cost - in the grand scheme of things - is negligible / nothing.
They have to go on the ends of the tow line (can't be incorporated into a bridle - tug or glider) but that's a pretty good thing - You know both planes are protected and the glider pilot is deprived of opportunities to screw things up.
You can drag the back end weak link assembly through the dust all summer long without degrading it.
The critical element(s) - the insert(s) - are subjected only to tension loads.
Cons...
As Danny said... These suckers are HEAVY.
A couple of years ago I ordered a couple of assemblies to check out for use with AT but was chilled a good bit upon opening the box.
The problem is that the bottom end inserts that tow Karen at 0.9 Gs are installed in the same hardware assembly as the ones for a 2250 pound glider towing at 1.0. The peripherals are ridiculously overstrength for what we're trying to do.
The increments available within our range are a bit far apart and based upon this from a previous edition of their website:
>
For weak link inserts with a breaking load less than 3.5 kN always use a reserve-insert weak link.
<
I suspect that they may be pushing the lower limit of that design concept a bit with the four lowest ratings.
I find none of these cons to be particularly big fucking deals - compared to the bullshit way we're doing things now they're totally off the screen.
I could be wrong about this but - using Spectra tow lines - I don't think anybody's getting anything recoiling in his face anyway.
3. Shear Links (My Stuff)
http://www.flickr.com/photos/aerotowrelease/
The number of dental floss stitches with which two elements are held together determines the strength rating.
Predictability is no worse than plus or minus twenty percent up to about 600 pounds direct load. Much after that it goes to hell pretty fast on the minus end.
Increments translate to about 16 to 18 pounds per stitch direct load - depending upon the configuration. (If the shear link is incorporated in a bridle this translates to about twice those figures in terms of tow line tension.)
Shear links may be configured for any bridle at either end of the tow line or on the ends of the tow line.
Pros...
They don't weigh anything.
While the tolerances may not be as good as Tost's, because they are available in finer increments, overall the effective tolerances are better.
As in the Tost weak links, the critical element (thread) is not subjected to interaction with other release system components and does not wear or degrade.
Nor does the critical element fatigue or degrade under stress right up to a shade under the shear link's rating.
All increments of all shear links are identifiable through a system of color coding.
A ribbon bridle - the shear link configuration for a primary bridle - is wrap resistant and features a secondary link at its bottom end which will all but guarantee a blow if a wrap is incurred under just normal tow tension.
Cons...
I don't know how a shear link installed on the back end of the tow line will hold up to repeated landing cycles.
It takes a full day to grind out a ribbon bridle and it's not compatible with a spinnaker shackle release.
Weak Link Flavors - Pros and Cons
1. Greenspot - 130 pound
Let's put everyone on two point (pilot and glider) Spectra bridles to simplify things. If you wanna adjust for one point you can go with a bit more weight on a given strength.
Nothing magical about it but it's very strong for its very minimal diameter.
If you use a larger diameter line the Fisherman's Knot with which you form the loop starts getting bulky and that can be problematic when the end of the bridle is trying to clear something. Better to just double the Greenspot.
A single loop on gliders up to the low two hundreds range isn't a bad solution. The direct load it will hold maxes out pretty reliably around 140 pounds (rather than the 260 popularly assumed). And on the light kites it tends not to get stressed out so you can also rely on it not falling way below that figure until it gets chewed up by the spinnaker shackle you shouldn't be using anyway.
On that note - I do have photos of a Tim Hinkel prototype release currently up near the top of the stack at:
http://www.flickr.com/photos/aerotowrelease/
(and, for future reference, filed in the Miscellaneous set). I'm hoping that he will be able to get these things in circulation before too long 'cause they're a much better, safer solution.
A double loop holds to a direct load of around 200 pounds and I recommend you start thinking about it as your glider starts getting much over about 225. At that figure you're in good shape at 1.55 Gs and by 248 pounds you're down to the 1.40 sweet spot.
If you stick with a single beyond the low two hundreds you can still be sure that your high end direct load won't exceed 140 but the low end reliability goes straight to hell. Thus Glen's shiny new hypothetical 0.7 G weak link may very well be down to 0.4 by the time he clears the cart (IF he clears the cart).
2. Tost
http://www.tost.de/
Pros...
The tolerances are very good / excellent.
Cost - in the grand scheme of things - is negligible / nothing.
They have to go on the ends of the tow line (can't be incorporated into a bridle - tug or glider) but that's a pretty good thing - You know both planes are protected and the glider pilot is deprived of opportunities to screw things up.
You can drag the back end weak link assembly through the dust all summer long without degrading it.
The critical element(s) - the insert(s) - are subjected only to tension loads.
Cons...
As Danny said... These suckers are HEAVY.
A couple of years ago I ordered a couple of assemblies to check out for use with AT but was chilled a good bit upon opening the box.
The problem is that the bottom end inserts that tow Karen at 0.9 Gs are installed in the same hardware assembly as the ones for a 2250 pound glider towing at 1.0. The peripherals are ridiculously overstrength for what we're trying to do.
The increments available within our range are a bit far apart and based upon this from a previous edition of their website:
>
For weak link inserts with a breaking load less than 3.5 kN always use a reserve-insert weak link.
<
I suspect that they may be pushing the lower limit of that design concept a bit with the four lowest ratings.
I find none of these cons to be particularly big fucking deals - compared to the bullshit way we're doing things now they're totally off the screen.
I could be wrong about this but - using Spectra tow lines - I don't think anybody's getting anything recoiling in his face anyway.
3. Shear Links (My Stuff)
http://www.flickr.com/photos/aerotowrelease/
The number of dental floss stitches with which two elements are held together determines the strength rating.
Predictability is no worse than plus or minus twenty percent up to about 600 pounds direct load. Much after that it goes to hell pretty fast on the minus end.
Increments translate to about 16 to 18 pounds per stitch direct load - depending upon the configuration. (If the shear link is incorporated in a bridle this translates to about twice those figures in terms of tow line tension.)
Shear links may be configured for any bridle at either end of the tow line or on the ends of the tow line.
Pros...
They don't weigh anything.
While the tolerances may not be as good as Tost's, because they are available in finer increments, overall the effective tolerances are better.
As in the Tost weak links, the critical element (thread) is not subjected to interaction with other release system components and does not wear or degrade.
Nor does the critical element fatigue or degrade under stress right up to a shade under the shear link's rating.
All increments of all shear links are identifiable through a system of color coding.
A ribbon bridle - the shear link configuration for a primary bridle - is wrap resistant and features a secondary link at its bottom end which will all but guarantee a blow if a wrap is incurred under just normal tow tension.
Cons...
I don't know how a shear link installed on the back end of the tow line will hold up to repeated landing cycles.
It takes a full day to grind out a ribbon bridle and it's not compatible with a spinnaker shackle release.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
1999/05/28 14:00
Ridgely
First day of operation of Highland Aerosports.
WNW at 15 on the surface, smooth - straight down Runway 30.
The wind is cranking as Sunny tries to help me load my glider on the cart for my first tow but the brackets won't accommodate my wheels so we have to pull them. I jokingly comment to myself, "OK, just don't turn the glider downwind."
Chad pulls me and the launch is REAL easy 'cause we only need about five miles per hour of groundspeed to crisply lift me off the cart.
The air is glassy smooth, I'm level and centered behind the Dragonfly at 125 feet doing nothing when the weak link decides to fail for no reason.
I'm a confirmed scatterbrain to begin with and a bit rusty on top of that.
I just automatically "turn the glider downwind" to return to base (instead of just maintaining my heading and pretty much hovering straight down).
I pass up one opportunity to turn back into the wind 'cause that was gonna put me down in the proximity of asphalt.
I pass up a second opportunity to turn back 'cause that was gonna put me down in the proximity of parked gliders.
Immediately thereafter it dawns on me that that second opportunity was also my LAST opportunity 'cause now I'm so low that I'm gonna cartwheel and kill myself if I try.
Oh shit. Ground screaming by. No wheels. This is really really bad.
But I used to be a pretty damn good dune pilot and I keep my airspeed up, flare the crap out of it, and get it stopped.
But I've still got a couple of tons of pressure on the back side of the glider so down it goes and, the wheels being in the bag, doesn't roll. The nose stays high and dry but the VG side (of course) downtube folds.
Everybody comes running up to see if I'm dead or just paralyzed from the neck down. I repeat to Sunny, "Just don't turn the glider downwind." and spend the next five minutes trying to convince everyone that I'm not hurt. (I'm pretty comfortable saying that nine out of ten Joe Weekends who had found themselves in that situation would have left the airport in helicopter.)
Then I spend a good chunk of the rest of the afternoon replacing the seventy dollar downtube so's I can get back on the cart and demonstrate to the crew that I'm not a total moron.
Did that totally unnecessary weak link break at 0.39 Gs - in and of itself - nearly get me killed? No.
But it sure as hell didn't make things any safer for me and it's probable that after one or two normal tows my brain would have kicked back into flying mode enough so that I wouldn't have made mistakes like that.
You try to make this game as idiot proof as possible and that damned piece of understrength string was nothing but a major fly in the ointment.
And I'm not the only one who's been more stupid setting up from 125 feet than he would have been from four times that.
Stay tuned - this is gonna get more interesting.
Ridgely
First day of operation of Highland Aerosports.
WNW at 15 on the surface, smooth - straight down Runway 30.
The wind is cranking as Sunny tries to help me load my glider on the cart for my first tow but the brackets won't accommodate my wheels so we have to pull them. I jokingly comment to myself, "OK, just don't turn the glider downwind."
Chad pulls me and the launch is REAL easy 'cause we only need about five miles per hour of groundspeed to crisply lift me off the cart.
The air is glassy smooth, I'm level and centered behind the Dragonfly at 125 feet doing nothing when the weak link decides to fail for no reason.
I'm a confirmed scatterbrain to begin with and a bit rusty on top of that.
I just automatically "turn the glider downwind" to return to base (instead of just maintaining my heading and pretty much hovering straight down).
I pass up one opportunity to turn back into the wind 'cause that was gonna put me down in the proximity of asphalt.
I pass up a second opportunity to turn back 'cause that was gonna put me down in the proximity of parked gliders.
Immediately thereafter it dawns on me that that second opportunity was also my LAST opportunity 'cause now I'm so low that I'm gonna cartwheel and kill myself if I try.
Oh shit. Ground screaming by. No wheels. This is really really bad.
But I used to be a pretty damn good dune pilot and I keep my airspeed up, flare the crap out of it, and get it stopped.
But I've still got a couple of tons of pressure on the back side of the glider so down it goes and, the wheels being in the bag, doesn't roll. The nose stays high and dry but the VG side (of course) downtube folds.
Everybody comes running up to see if I'm dead or just paralyzed from the neck down. I repeat to Sunny, "Just don't turn the glider downwind." and spend the next five minutes trying to convince everyone that I'm not hurt. (I'm pretty comfortable saying that nine out of ten Joe Weekends who had found themselves in that situation would have left the airport in helicopter.)
Then I spend a good chunk of the rest of the afternoon replacing the seventy dollar downtube so's I can get back on the cart and demonstrate to the crew that I'm not a total moron.
Did that totally unnecessary weak link break at 0.39 Gs - in and of itself - nearly get me killed? No.
But it sure as hell didn't make things any safer for me and it's probable that after one or two normal tows my brain would have kicked back into flying mode enough so that I wouldn't have made mistakes like that.
You try to make this game as idiot proof as possible and that damned piece of understrength string was nothing but a major fly in the ointment.
And I'm not the only one who's been more stupid setting up from 125 feet than he would have been from four times that.
Stay tuned - this is gonna get more interesting.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Damn.
This one isn't gonna be quite as smoking gun as it was when I was working off of the recollections people had posted on the skysailingtowing forum three years ago. Unfortunately, this morning I remembered where to look for a source seven years closer to reality.
In any case - we might as well assume that this "premature tow line release" was the result of a weak link failure 'cause:
that's exactly the sort of malfunction we see ALL THE TIME;
it's way more common than a release resulting from a mechanism adjustment problem;
it doesn't substantively matter; and
it probably was anyway.
>
chga Brydens incident column
1999/05/10 08:13:12
gmumford@...
chga@idbdnet.com, wrhgc@cdiprinceton.com
Bill's column:
...
Rob Richardson, a dedicated instructor, died in an aerotowing accident February 27, 1999 at his flight park in Arizona. He was conducting an instructional tandem aerotow flight and were in the process of launching from a ground launch vehicle when the accident occurred.
Rob had started to launch once but a premature tow line release terminated this effort after only a few meters into the launch roll-out. It is suspected the cart was rolled backwards a bit and the tow line was reattached to begin the launch process again. During the tug's roll-out for the second launch attempt, the tug pilot observed the glider clear the runway dust and then begin a left bank with no immediate correction. At that point he notice the launch cart was hanging below the glider and immediately released his end of the 240 ft. tow line. The tug never left the ground and tug pilot watched the glider continue a hard bank to the left achieving an altitude of approximately 25 feet. Impact was on the left wing and then the nose of the glider. Rob was killed immediately from severe neck and head trauma. Rob's body likely cushioned much of the student's impact. She was basically uninjured but suffered short term memory loss (not uncommon in hard crashes) and did not recall the events of the accident.
Of particular note is that the launch cart was not observed dangling from the glider. Rather it was seen positioned below the glider exactly as when the glider is resting upon the cart when on the ground. The cart construction was a rather typical triangle type arrangement. Approximately midway between the rear wheel and two front wheels, a cross member was connected between the two main frame rails running fore and aft. This cross member was parallel to the glider's control bar and located at about the pilot's waist when the pilot is positioned ready to launch. The tug pilot noted after the incident that the tow line was routed under this frame member on the cart and then connected to the release.
It is speculated, that after the aborted first launch, the bridle fell below this frame member and when it was picked up to reattached the tow line, it was pulled up but inadvertently was looped under the cross member. This would be consistent with the tug pilot's observations of the tow line after the crash and would explain how the cart could be held beneath the glider with the glider still positioned in the control bar and keel cradle points while airborn.
...
Discussion
These two accidents tend to be more disturbing than some because they happened to very experienced pilots... Rob owned a thriving hang gliding school. He and the tug pilot had performed over 700 aerotows together as a team. If these things can happen to our best pilots, it is indeed sobering and disconcerting for the rest of us...
<
My interpretation...
He was configured the same way just about all tandems are: spinnaker shackle on the keel, brake lever velcroed to the starboard downtube.
Anybody got a problem with anything so far? Good.
So what do we know?
Statistically, like damn near all of us, Rob never in his life been in a situation in which either his weak link or his parachute did him any good.
Assuming that the weak link failed it's a good bet it wasn't one of those deadly 1.4 G jobs that scares everyone so shitless. Understrength weak link pops... BFD - just hook up and start again.
(And JUST ONE MORE opportunity to screw things up - with a little help from the disrupted/nonstandard procedural routine.)
And allowing for the alternative scenario... Some release configurations require a bit of tweaking, but one that can't be relied on to stay secure probably after 700 tows ain't the greatest thing since sliced bread either.
Cory - the tug pilot - observes the glider turning to the left with no effective correction and - as per standard procedure - squeezes the lever.
(Had the glider - with the cart still glued to it - been tracking properly the standard procedure would have been to continue the tow normally to allow the glider time to deal with the problem.)
Rob knew Rob was in deep shit WELL before Cory knew Rob was in deep shit. Rob knew he was in deep shit as soon as he lifted off the cart - and didn't.
When - from a good chunk of a football field away - Cory determined that Rob was in deep shit he immediately hit the release. So why didn't Rob hit the release as soon as the words "OH SHIT!" came to mind? Yeah, you're way ahead of me.
>
FAR Part 91.309
(i) A safety link is installed at the point of attachment of the towline to the glider with A BREAKING STRENGTH NOT LESS THAN 80 PERCENT OF THE MAXIMUM CERTIFICATED OPERATING WEIGHT OF THE GLIDER and not greater than twice this operating weight.
<
>
Skyting Criteria
GROUP 2 - Safe Transition
06: Reliable Releases
THE RELEASE DEVICES AND THEIR ACTIVATION METHODS MUST BE STURDY, RAPID, AND RELIABLE. (RELEASE ACTIVATION MUST BE READILY ACCESSIBLE TO THE PILOT REGARDLESS OF WHERE HIS HANDS ARE OR WHERE HIS BODY HAS SHIFTED.
This one isn't gonna be quite as smoking gun as it was when I was working off of the recollections people had posted on the skysailingtowing forum three years ago. Unfortunately, this morning I remembered where to look for a source seven years closer to reality.
In any case - we might as well assume that this "premature tow line release" was the result of a weak link failure 'cause:
that's exactly the sort of malfunction we see ALL THE TIME;
it's way more common than a release resulting from a mechanism adjustment problem;
it doesn't substantively matter; and
it probably was anyway.
>
chga Brydens incident column
1999/05/10 08:13:12
gmumford@...
chga@idbdnet.com, wrhgc@cdiprinceton.com
Bill's column:
...
Rob Richardson, a dedicated instructor, died in an aerotowing accident February 27, 1999 at his flight park in Arizona. He was conducting an instructional tandem aerotow flight and were in the process of launching from a ground launch vehicle when the accident occurred.
Rob had started to launch once but a premature tow line release terminated this effort after only a few meters into the launch roll-out. It is suspected the cart was rolled backwards a bit and the tow line was reattached to begin the launch process again. During the tug's roll-out for the second launch attempt, the tug pilot observed the glider clear the runway dust and then begin a left bank with no immediate correction. At that point he notice the launch cart was hanging below the glider and immediately released his end of the 240 ft. tow line. The tug never left the ground and tug pilot watched the glider continue a hard bank to the left achieving an altitude of approximately 25 feet. Impact was on the left wing and then the nose of the glider. Rob was killed immediately from severe neck and head trauma. Rob's body likely cushioned much of the student's impact. She was basically uninjured but suffered short term memory loss (not uncommon in hard crashes) and did not recall the events of the accident.
Of particular note is that the launch cart was not observed dangling from the glider. Rather it was seen positioned below the glider exactly as when the glider is resting upon the cart when on the ground. The cart construction was a rather typical triangle type arrangement. Approximately midway between the rear wheel and two front wheels, a cross member was connected between the two main frame rails running fore and aft. This cross member was parallel to the glider's control bar and located at about the pilot's waist when the pilot is positioned ready to launch. The tug pilot noted after the incident that the tow line was routed under this frame member on the cart and then connected to the release.
It is speculated, that after the aborted first launch, the bridle fell below this frame member and when it was picked up to reattached the tow line, it was pulled up but inadvertently was looped under the cross member. This would be consistent with the tug pilot's observations of the tow line after the crash and would explain how the cart could be held beneath the glider with the glider still positioned in the control bar and keel cradle points while airborn.
...
Discussion
These two accidents tend to be more disturbing than some because they happened to very experienced pilots... Rob owned a thriving hang gliding school. He and the tug pilot had performed over 700 aerotows together as a team. If these things can happen to our best pilots, it is indeed sobering and disconcerting for the rest of us...
<
My interpretation...
He was configured the same way just about all tandems are: spinnaker shackle on the keel, brake lever velcroed to the starboard downtube.
Anybody got a problem with anything so far? Good.
So what do we know?
Statistically, like damn near all of us, Rob never in his life been in a situation in which either his weak link or his parachute did him any good.
Assuming that the weak link failed it's a good bet it wasn't one of those deadly 1.4 G jobs that scares everyone so shitless. Understrength weak link pops... BFD - just hook up and start again.
(And JUST ONE MORE opportunity to screw things up - with a little help from the disrupted/nonstandard procedural routine.)
And allowing for the alternative scenario... Some release configurations require a bit of tweaking, but one that can't be relied on to stay secure probably after 700 tows ain't the greatest thing since sliced bread either.
Cory - the tug pilot - observes the glider turning to the left with no effective correction and - as per standard procedure - squeezes the lever.
(Had the glider - with the cart still glued to it - been tracking properly the standard procedure would have been to continue the tow normally to allow the glider time to deal with the problem.)
Rob knew Rob was in deep shit WELL before Cory knew Rob was in deep shit. Rob knew he was in deep shit as soon as he lifted off the cart - and didn't.
When - from a good chunk of a football field away - Cory determined that Rob was in deep shit he immediately hit the release. So why didn't Rob hit the release as soon as the words "OH SHIT!" came to mind? Yeah, you're way ahead of me.
>
FAR Part 91.309
(i) A safety link is installed at the point of attachment of the towline to the glider with A BREAKING STRENGTH NOT LESS THAN 80 PERCENT OF THE MAXIMUM CERTIFICATED OPERATING WEIGHT OF THE GLIDER and not greater than twice this operating weight.
<
>
Skyting Criteria
GROUP 2 - Safe Transition
06: Reliable Releases
THE RELEASE DEVICES AND THEIR ACTIVATION METHODS MUST BE STURDY, RAPID, AND RELIABLE. (RELEASE ACTIVATION MUST BE READILY ACCESSIBLE TO THE PILOT REGARDLESS OF WHERE HIS HANDS ARE OR WHERE HIS BODY HAS SHIFTED.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
>
jimrooney
2008/12/06 20:01:49
Don't ever pull a solo at full throttle... they will not be able to climb with you. You can tow them at 28mph and you'll still leave them in the dust... they just won't be able to climb with you... weaklinks will go left and right.
<
Yeah, the glider itself wouldn't have any trouble - but the weak links will go left and right. ('Cept for mine.)
jimrooney
2008/12/06 20:01:49
Don't ever pull a solo at full throttle... they will not be able to climb with you. You can tow them at 28mph and you'll still leave them in the dust... they just won't be able to climb with you... weaklinks will go left and right.
<
Yeah, the glider itself wouldn't have any trouble - but the weak links will go left and right. ('Cept for mine.)
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
1996/05/09
Steve Kinsley
Personal opinion. While I don't know the circumstances of Frank's death and I am not an awesome tow type dude, I think tow releases, all of them, stink on ice. Reason: You need two hands to drive a hang glider. You 'specially need two hands if it starts to turn on tow. If you let go to release, the glider can almost instantly assume a radical attitude.
-
2006/01/24
Davis Straub
Bill Moyes argues that you should not have to move your hand from the base bar to release. That is because your natural inclination is to continue to hold onto the base bar in tough conditions and to try to fly the glider when you should be releasing.
I'm willing to put the barrel release within a few inches of my hand.
-
2004/08/02
Davis Straub
Finger Lakes Aerosport Flight Park
Hands on the basetube, brake lever on the downtube, trashed demo glider, thirteen stitches in the lip.
-
2008/10/27
Peter Birren
I know about this type of accident because it happened to me, breaking 4 ribs and my larynx... and I was aerotowing using a dolly...
(Editor's note: and a release configuration which necessitated removal of a hand from the basetube.)
-
Marc Fink
2007/05/18
Tad...
Please get in touch with Peter Birren and get some info on development and implementation of safety systems.
-
2008/10/27
Peter Birren
Imagine if you will, just coming off the cart and center punching a thermal which takes you instantly straight up while the tug is still on the ground. Know what happens? VERY high towline forces and an over-the-top lockout. You'll have both hands on the basetube pulling it well past your knees but the glider doesn't come down and still the weaklink doesn't break (.8G). SO YOU PULL WHATEVER RELEASE YOU HAVE BUT THE ONE HAND STILL ON THE BASETUBE ISN'T ENOUGH TO HOLD THE NOSE DOWN AND YOU POP UP AND OVER INTO AN UNPLANNED SEMI-LOOP. Been there, done that... at maybe 200 feet agl.
(Editor's note: Imagine if you will, just coming off the cart and NOT center punching that thermal.)
-
Holly Korzilius
2005/05/29
Severe oscillations, bent pin barrel release on shoulder.
-
Lauren Tjaden
2005/03/05
Reaching that handle way out to the side can be challenging in a hard turn.
-
Lauren Tjaden
2008/03/23
When Jim got me locked out to the right, i couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the f'ing release slid around when i tried to hit it. the barrel release wouldn't work because we had too much pressure on it.
-
carweill
2008/11/30
I tried to release but my body was off centered and COULD NOT REACH THE RELEASE. I kept trying and was close to 90 deg. All these happen very quickly, as anyone that has experienced a lock out would tell you. I heard a snap, and then just like the sound of a WWII plane just shut down hurdling to the ground, only the ball of fire was missing. The tug weak link broke off at 1000ft, in less than a second the glider was at 500ft.
-
Mike Haas
2004/06/24
Highly experienced mountain pilot aerotowing a newly-purchased glider experienced a lockout at low altitude. Witness reports indicate that the glider began oscillating immediately after leaving the launch dolly. The weak link broke after the glider entered a lockout attitude. Once free, the glider was reportedly too low (50-65' AGL, estimated) to recover from the unusual attitude and impacted the ground in a steep dive. The pilot suffered fatal injuries due to blunt trauma. There is no evidence that the pilot made an attempt to release from tow prior to the weak link break, the gate was found closed on the Wallaby-style tow release.
-
Skyting Criteria
GROUP 2 - Safe Transition
06: Reliable Releases
The release devices and their activation methods must be sturdy, rapid, and reliable. (Release activation MUST be readily accessible to the pilot regardless of where his hands are or where his body has shifted. Only single-point release systems should be used.)
-
USHPA SOP 12-02.10:B:6
A release must be placed at the hang glider end of the tow line within easy reach of the pilot.
-
2008/12/08
Definition:
AT hang glider - An aircraft that blows off tow constantly when it's trying to stay on but can't buy its way off when the life of the pilot is dependent upon it doing so.
-
Steve Kinsley
Personal opinion. While I don't know the circumstances of Frank's death and I am not an awesome tow type dude, I think tow releases, all of them, stink on ice. Reason: You need two hands to drive a hang glider. You 'specially need two hands if it starts to turn on tow. If you let go to release, the glider can almost instantly assume a radical attitude.
-
2006/01/24
Davis Straub
Bill Moyes argues that you should not have to move your hand from the base bar to release. That is because your natural inclination is to continue to hold onto the base bar in tough conditions and to try to fly the glider when you should be releasing.
I'm willing to put the barrel release within a few inches of my hand.
-
2004/08/02
Davis Straub
Finger Lakes Aerosport Flight Park
Hands on the basetube, brake lever on the downtube, trashed demo glider, thirteen stitches in the lip.
-
2008/10/27
Peter Birren
I know about this type of accident because it happened to me, breaking 4 ribs and my larynx... and I was aerotowing using a dolly...
(Editor's note: and a release configuration which necessitated removal of a hand from the basetube.)
-
Marc Fink
2007/05/18
Tad...
Please get in touch with Peter Birren and get some info on development and implementation of safety systems.
-
2008/10/27
Peter Birren
Imagine if you will, just coming off the cart and center punching a thermal which takes you instantly straight up while the tug is still on the ground. Know what happens? VERY high towline forces and an over-the-top lockout. You'll have both hands on the basetube pulling it well past your knees but the glider doesn't come down and still the weaklink doesn't break (.8G). SO YOU PULL WHATEVER RELEASE YOU HAVE BUT THE ONE HAND STILL ON THE BASETUBE ISN'T ENOUGH TO HOLD THE NOSE DOWN AND YOU POP UP AND OVER INTO AN UNPLANNED SEMI-LOOP. Been there, done that... at maybe 200 feet agl.
(Editor's note: Imagine if you will, just coming off the cart and NOT center punching that thermal.)
-
Holly Korzilius
2005/05/29
Severe oscillations, bent pin barrel release on shoulder.
-
Lauren Tjaden
2005/03/05
Reaching that handle way out to the side can be challenging in a hard turn.
-
Lauren Tjaden
2008/03/23
When Jim got me locked out to the right, i couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the f'ing release slid around when i tried to hit it. the barrel release wouldn't work because we had too much pressure on it.
-
carweill
2008/11/30
I tried to release but my body was off centered and COULD NOT REACH THE RELEASE. I kept trying and was close to 90 deg. All these happen very quickly, as anyone that has experienced a lock out would tell you. I heard a snap, and then just like the sound of a WWII plane just shut down hurdling to the ground, only the ball of fire was missing. The tug weak link broke off at 1000ft, in less than a second the glider was at 500ft.
-
Mike Haas
2004/06/24
Highly experienced mountain pilot aerotowing a newly-purchased glider experienced a lockout at low altitude. Witness reports indicate that the glider began oscillating immediately after leaving the launch dolly. The weak link broke after the glider entered a lockout attitude. Once free, the glider was reportedly too low (50-65' AGL, estimated) to recover from the unusual attitude and impacted the ground in a steep dive. The pilot suffered fatal injuries due to blunt trauma. There is no evidence that the pilot made an attempt to release from tow prior to the weak link break, the gate was found closed on the Wallaby-style tow release.
-
Skyting Criteria
GROUP 2 - Safe Transition
06: Reliable Releases
The release devices and their activation methods must be sturdy, rapid, and reliable. (Release activation MUST be readily accessible to the pilot regardless of where his hands are or where his body has shifted. Only single-point release systems should be used.)
-
USHPA SOP 12-02.10:B:6
A release must be placed at the hang glider end of the tow line within easy reach of the pilot.
-
2008/12/08
Definition:
AT hang glider - An aircraft that blows off tow constantly when it's trying to stay on but can't buy its way off when the life of the pilot is dependent upon it doing so.
-
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
So if you devour as much information on hang glider aerotowing as you can get your hands on, you start seeing patterns.
1. The number of weak link breaks that have positively affected safety for a halfway competent pilot who's been doing his job on the back end of the rope is ZERO.
2. Every single time a release mechanism has failed it has done so for a reason that had been easily predicted far in advance. There has never been a failure of a properly engineered and preflighted release.
3. ALL FATAL AND SERIOUS ACCIDENTS HAVE INVOLVED RELEASES WHICH REQUIRE THE PILOT TO REMOVE A HAND FROM THE BASETUBE.
Rob Richardson, Davis Straub, Holly Korzillius, Mike Haas, Tocumwal, Peter Birren...
(Bill Bennett / Mike Del Signore and Arlan Birkett / Jeremiah Thompson would fit the category but the releases had no bearing on the accidents - the former tandem stalled, the latter was divergent 'cause the luff lines were loose.)
Same with the ones that lucked out 'cause they had or happened to have enough air under them: Larry Bunner, Carlos Weill, Paul and Lauren Tjaden, Peter Birren...
>
http://www.aviationbanter.com/showthread.php?t=40965
Are Weak Links really Necessary for Aero Tow?
#34
2006/09/18 15:30
Bill Daniels
I would like to add, however, that at least my reading of accident reports suggests that a fatal glider accident is more likely when the towline fails prematurely. For that reason, I like to stay near the stronger end of the FAR 80% - 200% range.
Actually, reading the POH for several German gliders, I note the weak link for aerotow is specified as an exact figure. For example, the weak link for both aero tow and winch for my Nimbus 2C is specified as 600 Kg (1323 Lbs) or a blue Tost weak link. The tolerance is + or - 10%. The US Airworthiness Certificate specifies that the Nimbus 2C is to be flown as specified in the Pilots Handbook (POH). Considering the possible flying weights, this ranges between 95% - 160% which is a narrower range than specified in the FAR's.
Makes me wonder if we should be using Tost weak links instead of old bits of rope.
<
Note the convergence of thinking amongst people capable of it.
1. The number of weak link breaks that have positively affected safety for a halfway competent pilot who's been doing his job on the back end of the rope is ZERO.
2. Every single time a release mechanism has failed it has done so for a reason that had been easily predicted far in advance. There has never been a failure of a properly engineered and preflighted release.
3. ALL FATAL AND SERIOUS ACCIDENTS HAVE INVOLVED RELEASES WHICH REQUIRE THE PILOT TO REMOVE A HAND FROM THE BASETUBE.
Rob Richardson, Davis Straub, Holly Korzillius, Mike Haas, Tocumwal, Peter Birren...
(Bill Bennett / Mike Del Signore and Arlan Birkett / Jeremiah Thompson would fit the category but the releases had no bearing on the accidents - the former tandem stalled, the latter was divergent 'cause the luff lines were loose.)
Same with the ones that lucked out 'cause they had or happened to have enough air under them: Larry Bunner, Carlos Weill, Paul and Lauren Tjaden, Peter Birren...
>
http://www.aviationbanter.com/showthread.php?t=40965
Are Weak Links really Necessary for Aero Tow?
#34
2006/09/18 15:30
Bill Daniels
I would like to add, however, that at least my reading of accident reports suggests that a fatal glider accident is more likely when the towline fails prematurely. For that reason, I like to stay near the stronger end of the FAR 80% - 200% range.
Actually, reading the POH for several German gliders, I note the weak link for aerotow is specified as an exact figure. For example, the weak link for both aero tow and winch for my Nimbus 2C is specified as 600 Kg (1323 Lbs) or a blue Tost weak link. The tolerance is + or - 10%. The US Airworthiness Certificate specifies that the Nimbus 2C is to be flown as specified in the Pilots Handbook (POH). Considering the possible flying weights, this ranges between 95% - 160% which is a narrower range than specified in the FAR's.
Makes me wonder if we should be using Tost weak links instead of old bits of rope.
<
Note the convergence of thinking amongst people capable of it.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Biran,
NOW do ya see why:
spade identification is such a critical part of the process; and that
even if it sounds a little preemptive - I know these folk well enough after all these years to call them consistently and accurately?
David,
Don't worry, this is about the seventh or eighth time Marc has been outta here for good. Unfortunately it never lasts for more than about an hour and a half.
If, however, he goes for as much as a few days this time and you miss his perspectives...
It's always some variation of:
"We're obviously doing everything right 'cause this is the way we've always done it. And even if we weren't, the Shining Path would be revealed to us by someone who flies all the time. It couldn't possibly come from you (me)."
If the departure lasts for longer than you can stand - just lemme know and I'll ghost write a few for you. I've known Marc long enough to know what he's gonna say long before he knows what he's gonna say. You'll never notice the difference.
Now as to this low-tech approach thing... You obviously don't know how this forum works - so lemme set you straight...
You MUST use the "Foe" feature if you don't want to read someone's submissions. Otherwise you are REQUIRED to read every word of each of his posts - as was the case prior to the introduction of this digital wonder.
And, of course, engaging the blocking setting entitles you to comment on what a clueless jerk the blockee is - based entirely upon what you imagine he is saying.
Cragin and Jim really have this system down. They're your go-to guys if you need any tips.
Sparky!
Since when did YOU develop an interest in AT release technology?
NOW do ya see why:
spade identification is such a critical part of the process; and that
even if it sounds a little preemptive - I know these folk well enough after all these years to call them consistently and accurately?
David,
Don't worry, this is about the seventh or eighth time Marc has been outta here for good. Unfortunately it never lasts for more than about an hour and a half.
If, however, he goes for as much as a few days this time and you miss his perspectives...
It's always some variation of:
"We're obviously doing everything right 'cause this is the way we've always done it. And even if we weren't, the Shining Path would be revealed to us by someone who flies all the time. It couldn't possibly come from you (me)."
If the departure lasts for longer than you can stand - just lemme know and I'll ghost write a few for you. I've known Marc long enough to know what he's gonna say long before he knows what he's gonna say. You'll never notice the difference.
Now as to this low-tech approach thing... You obviously don't know how this forum works - so lemme set you straight...
You MUST use the "Foe" feature if you don't want to read someone's submissions. Otherwise you are REQUIRED to read every word of each of his posts - as was the case prior to the introduction of this digital wonder.
And, of course, engaging the blocking setting entitles you to comment on what a clueless jerk the blockee is - based entirely upon what you imagine he is saying.
Cragin and Jim really have this system down. They're your go-to guys if you need any tips.
Sparky!
Since when did YOU develop an interest in AT release technology?
Re: Weak link question
Tad wrote:
Umm...uh...gee, guess I do. There's some...uh...delusional behavior going around...NOW do ya see why...spade identification is such a critical part of the process;
Brian Vant-Hull
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Brian,
OK, that was probably a dig against me. But I'm not sure how the "delusional" thing applies here.
I've been doing some reading on sailplane towing lately - having accidental googled my way into parallel discussions.
The density of intelligent life forms out there is definitely a lot higher and they at least have a real good understanding of what I weak link is (and isn't) - but they're not as ironclad as I had earlier presumed.
For a long time I've wanted to get my hands on a Tost sailplane release to see how "Old Europe" does things (by which, of course, I mean right) and called Tim Mara of Wings And Wheels.
In the course of placing the order I asked him for a guesstimate of sailplane AT weak link failure rates. He came up with one in a thousand. That's about a hundred times better than what we're doing.
We won't be able to match that no matter what 'cause we can't keep our kites under control as well as they do but we could get up to one in a hundred in our sleep if we'd just start reading and following our own rules.
To me "delusional" describes a population which fails to see the release failures experienced and described by Lauren and Carlos as any problem whatsoever yet recoils in horror at the experience Paul had with a weak link of exactly the rating it should have had.
And I'm still waiting to hear a single word explaining how that incident was any more dangerous than a tandem lockout or even - in fact - how it was dangerous in the least anyway.
So how 'bout a different adjective?
>
http://www.aviationbanter.com/showthread.php?t=40965
Are Weak Links really Necessary for Aero Tow?
#31
2006/09/18 02:45
Don Johnstone
Posts: 36
A very good friend of mine died several years ago in a tug upset.
He was aero-towing I believe a Ka6 out of a wave site when turbulence caused the glider to lose sight of the tug at about 300ft. The glider pilot did not release and the tug pilot could not as his inertia reel harness had locked and he was unable to reach the release (conclusion of the AAIB). The uspet was so bad that the tug was hanging vertically from the glider before the rope broke. The resulting dive was irrecoverable and the pilot died when the tug hit the ground, the glider pilot of course survived.
<
OK, that was probably a dig against me. But I'm not sure how the "delusional" thing applies here.
I've been doing some reading on sailplane towing lately - having accidental googled my way into parallel discussions.
The density of intelligent life forms out there is definitely a lot higher and they at least have a real good understanding of what I weak link is (and isn't) - but they're not as ironclad as I had earlier presumed.
For a long time I've wanted to get my hands on a Tost sailplane release to see how "Old Europe" does things (by which, of course, I mean right) and called Tim Mara of Wings And Wheels.
In the course of placing the order I asked him for a guesstimate of sailplane AT weak link failure rates. He came up with one in a thousand. That's about a hundred times better than what we're doing.
We won't be able to match that no matter what 'cause we can't keep our kites under control as well as they do but we could get up to one in a hundred in our sleep if we'd just start reading and following our own rules.
To me "delusional" describes a population which fails to see the release failures experienced and described by Lauren and Carlos as any problem whatsoever yet recoils in horror at the experience Paul had with a weak link of exactly the rating it should have had.
And I'm still waiting to hear a single word explaining how that incident was any more dangerous than a tandem lockout or even - in fact - how it was dangerous in the least anyway.
So how 'bout a different adjective?
>
http://www.aviationbanter.com/showthread.php?t=40965
Are Weak Links really Necessary for Aero Tow?
#31
2006/09/18 02:45
Don Johnstone
Posts: 36
A very good friend of mine died several years ago in a tug upset.
He was aero-towing I believe a Ka6 out of a wave site when turbulence caused the glider to lose sight of the tug at about 300ft. The glider pilot did not release and the tug pilot could not as his inertia reel harness had locked and he was unable to reach the release (conclusion of the AAIB). The uspet was so bad that the tug was hanging vertically from the glider before the rope broke. The resulting dive was irrecoverable and the pilot died when the tug hit the ground, the glider pilot of course survived.
<
Re: Weak link question
Okay, Tad, I was too obvious and you caught me.
The delusional comes in thinking that writing off highly experienced members of our community as mentally handicapped is a useful thing to do. Even if they're wrong (and there's always loopholes to any theory, so I'll never say anyone is completely wrong) these are the people who you're better off having on your side.
The delusional comes in thinking that writing off highly experienced members of our community as mentally handicapped is a useful thing to do. Even if they're wrong (and there's always loopholes to any theory, so I'll never say anyone is completely wrong) these are the people who you're better off having on your side.
Brian Vant-Hull
Re: Weak link question
Awe Brian.... we were taking bets on how long Tad would talk to himself if we all ignored him.
Well, that ends it... 10 unanswered posts is the current record.
I'm not outting the winner... perhaps he'll give it an other go.
Jim
Well, that ends it... 10 unanswered posts is the current record.
I'm not outting the winner... perhaps he'll give it an other go.
Jim
Re: Weak link question
hah! i was considering having a parallel thread counting off the days.
there's something perverse about that brian. he gets a perverse pleasure in being perverse.
( i used that line already haven't i)
garyD
there's something perverse about that brian. he gets a perverse pleasure in being perverse.
( i used that line already haven't i)
garyD
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Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Brian,
Here's some of the stuff I've got on my side so far - mostly or entirely...
documentation:
FAA FAR Part 91.309
USHPA SOP 12-02.10:B:5
Sailplane Pilots' Operating Handbooks
Skyting Criteria - Group 2 - 07
Donnell Hewett - 2008/11/05 concession letter
flight parks, tow operators, schools:
Dynamic Flight - Australia
Tow Me Up - US
Marco Vento - Portugal
pilots who figured it out on their own:
Dr. James Freeman - Dynamic Flight
Davis Straub - Oz Report
Campbell Bowen - Quest Air
Steve Kroop - Quest Air Office Manager; Flytec USA
Jim Lamb - ATOS, US Distributor
Danny Brotto
The million comp pilots told by Jim Rooney to "suck it up".
pilots I've converted, enabled, and/or equipped:
Sunny Venesky - Highland Aerosports
Campbell Bowen - Quest Air
Steve Kinsley
Steve Padgett
Hugh McElrath
Rich Cizauskas
Brian Vant-Hull
Christy Huddle
Tim Hinkel
Here's the stuff that's keeping us locked in the Dark Ages:
-
highly experienced members of our community.
-
When a community starts off doing something wrong from Day 1 (as you very well know we have) - The most highly experienced members are the most dangerous and recalcitrant elements.
Jim Rooney - as he never tires of telling us - has such a high level of experience that it dwarfs what the rest of us have combined.
Like damn near all of us he was indoctrinated with the misconception that a hang check is a required preflight procedure.
Steve Kinsley - several deaths ago - had correctly identified the hang check as the problem - not the solution. I don't like them, I don't do them. I follow the rules (decades before I realized those were - in fact - the rules) and do hook-in checks.
So I was a little irritated when Jim - in the course of checking me out on the flight line three seasons ago - insisted that I perform one. At Ridgely, no less, where it's even more useless than it is at the Pulpit.
He had never gone to source material - the SOPs / Pilot Proficiency System - to learn what he was SUPPOSED to be doing and thus found himself in a coma a few months afterwards.
And we're gonna keep on killing people like this 'cause of all these members of our community highly experienced in doing things wrong.
I want highly experienced people on my side but just the ones with brains. I can absolutely guarantee you that if Chad's parachute canister had been aimed in a better direction half a dozen years ago this conversation would have been OVER about 225 posts ago.
Instead - here we are in pure unadulterated Catch 22 Hell with our highly experienced resident expert on everything tug pilot simultaneously insisting that Janni fly at 1.0 Gs and refusing to tow him if he goes that high.
>
Even if they're wrong (and there's always loopholes to any theory, so I'll never say anyone is completely wrong)...
<
Well, it's a dirty job but somebody's gotta do it.
"It's just as safe to fly without wheels as with them."
"There is a perfectly good reason for the pin to be bent in a Bailey release."
"A single loop of Greenspot works just great for Karen and Glen and everyone in between."
"It's OK to mount a release actuator on a downtube."
Anyone who tells you that you won't kill more people with release actuators for which you have to reach is an idiot. We've had the body counts - in both sailplaning and hang gliding - to flatly refute that position for a very long time.
THERE ARE -NO- LOOPHOLES IN THESE ISSUES. That's why we have rules that no one follows.
Yeah - Janni is totally, one hundred percent, absolutely, completely WRONG!
>
Are Weak Links really Necessary for Aero Tow?
Bill Daniels
I would like to add, however, that at least my reading of accident reports suggests that a fatal glider accident is more likely when the towline fails prematurely.
<
We should be having a heated debate about which is best - 1.2, 1.4, or 1.6. Instead we're tolerating Janni's position of going to a THIRD of that range 'cause he's too lazy to undo the velcro on his brake lever and move it from his downtube to his basetube in the mistaken belief that this clueless tack can compensate for substandard equipment, decision making ability, and overall pilot competence. This flies in the face of every sane aircraft towing standard that's been established in the past century. It even contradicts a statement form There's-No-Such-Thing-As-Too-Weak Jim. People like that need to be protected from themselves.
The sailplane people don't go through this bullshit. You buy a plane, you open the owner's manual, it says use a Number 04 / 600 decaNewton / Blue / 1.4 G Tost weak link, there's one in the glove box - and you do it. End of problem.
We need to fix the rules that are obviously broken and start following the ones that obviously aren't.
Here's some of the stuff I've got on my side so far - mostly or entirely...
documentation:
FAA FAR Part 91.309
USHPA SOP 12-02.10:B:5
Sailplane Pilots' Operating Handbooks
Skyting Criteria - Group 2 - 07
Donnell Hewett - 2008/11/05 concession letter
flight parks, tow operators, schools:
Dynamic Flight - Australia
Tow Me Up - US
Marco Vento - Portugal
pilots who figured it out on their own:
Dr. James Freeman - Dynamic Flight
Davis Straub - Oz Report
Campbell Bowen - Quest Air
Steve Kroop - Quest Air Office Manager; Flytec USA
Jim Lamb - ATOS, US Distributor
Danny Brotto
The million comp pilots told by Jim Rooney to "suck it up".
pilots I've converted, enabled, and/or equipped:
Sunny Venesky - Highland Aerosports
Campbell Bowen - Quest Air
Steve Kinsley
Steve Padgett
Hugh McElrath
Rich Cizauskas
Brian Vant-Hull
Christy Huddle
Tim Hinkel
Here's the stuff that's keeping us locked in the Dark Ages:
-
highly experienced members of our community.
-
When a community starts off doing something wrong from Day 1 (as you very well know we have) - The most highly experienced members are the most dangerous and recalcitrant elements.
Jim Rooney - as he never tires of telling us - has such a high level of experience that it dwarfs what the rest of us have combined.
Like damn near all of us he was indoctrinated with the misconception that a hang check is a required preflight procedure.
Steve Kinsley - several deaths ago - had correctly identified the hang check as the problem - not the solution. I don't like them, I don't do them. I follow the rules (decades before I realized those were - in fact - the rules) and do hook-in checks.
So I was a little irritated when Jim - in the course of checking me out on the flight line three seasons ago - insisted that I perform one. At Ridgely, no less, where it's even more useless than it is at the Pulpit.
He had never gone to source material - the SOPs / Pilot Proficiency System - to learn what he was SUPPOSED to be doing and thus found himself in a coma a few months afterwards.
And we're gonna keep on killing people like this 'cause of all these members of our community highly experienced in doing things wrong.
I want highly experienced people on my side but just the ones with brains. I can absolutely guarantee you that if Chad's parachute canister had been aimed in a better direction half a dozen years ago this conversation would have been OVER about 225 posts ago.
Instead - here we are in pure unadulterated Catch 22 Hell with our highly experienced resident expert on everything tug pilot simultaneously insisting that Janni fly at 1.0 Gs and refusing to tow him if he goes that high.
>
Even if they're wrong (and there's always loopholes to any theory, so I'll never say anyone is completely wrong)...
<
Well, it's a dirty job but somebody's gotta do it.
"It's just as safe to fly without wheels as with them."
"There is a perfectly good reason for the pin to be bent in a Bailey release."
"A single loop of Greenspot works just great for Karen and Glen and everyone in between."
"It's OK to mount a release actuator on a downtube."
Anyone who tells you that you won't kill more people with release actuators for which you have to reach is an idiot. We've had the body counts - in both sailplaning and hang gliding - to flatly refute that position for a very long time.
THERE ARE -NO- LOOPHOLES IN THESE ISSUES. That's why we have rules that no one follows.
Yeah - Janni is totally, one hundred percent, absolutely, completely WRONG!
>
Are Weak Links really Necessary for Aero Tow?
Bill Daniels
I would like to add, however, that at least my reading of accident reports suggests that a fatal glider accident is more likely when the towline fails prematurely.
<
We should be having a heated debate about which is best - 1.2, 1.4, or 1.6. Instead we're tolerating Janni's position of going to a THIRD of that range 'cause he's too lazy to undo the velcro on his brake lever and move it from his downtube to his basetube in the mistaken belief that this clueless tack can compensate for substandard equipment, decision making ability, and overall pilot competence. This flies in the face of every sane aircraft towing standard that's been established in the past century. It even contradicts a statement form There's-No-Such-Thing-As-Too-Weak Jim. People like that need to be protected from themselves.
The sailplane people don't go through this bullshit. You buy a plane, you open the owner's manual, it says use a Number 04 / 600 decaNewton / Blue / 1.4 G Tost weak link, there's one in the glove box - and you do it. End of problem.
We need to fix the rules that are obviously broken and start following the ones that obviously aren't.
-
davidtheamazing1
- Posts: 306
- Joined: Wed Jan 26, 2005 1:26 am
- Location: DC Area - Hang 3!!
- Contact:
Re: Weak link question
245 Posts and counting... Jerry! Jerry!