Okay, just wanted to make sure it was clear.
So Janni, either you think my link is dangerously strong, or yours is inconveniently weak. Until some very experienced AT jock pulls me aside and tells me I should be worried about my safety, I'll say your link is inconveniently weak.
Unfortunately, we don't have a material with which to adjust it that every tow pilot will recognize and be comfortable with. The next step up is 3 strands, and that's not 100 lbs below the tug.
Tad is making adjustable links, but the next step would be convincing everyone that they are as reliable as he says (and greenspot wears out, remember), and more importantly, that he's not making any that are stronger than 100 lbs below the tug. I guess that doesn't leave much room to maneuver anyway, does it?
Beef up the tug so it can take a stronger link? Moving into uncharted territory.
No more little debbie cakes for me, gotta keep my g loading down.
Weak link question
Moderator: CHGPA BOD
Re: Weak link question
Brian Vant-Hull
Re: Weak link question
It's not "uncharted territory"... you're just not aware of what's been done. Just as you weren't aware of the reason for 3 strand links on the tug.Beef up the tug so it can take a stronger link? Moving into uncharted territory.
The trouble with Tad's links is not convincing people. It's not an opinion problem. It's a testing problem. Just as a hand made glider would be a problem.
You're probably also not aware that me and Paul had a pretty big argument over his Tad-o-link before he locked out in Texas. All these same arguments. Over and over. No one listens till they scare themselves...
-slaps forehead-Until some very experienced AT jock
Jim
Re: Weak link question
Janni and I fly with the same standard weak link. I was just trying to make Janni's life as easy as mine, but it's harder than I thought it would be.
Brian Vant-Hull
Re: Weak link question
Brian, I never said you were flying with a dangerously strong weak link. I never said I was inconvenienced by mine.
I may break a few more than you do in a season's time, but they may also break sooner than yours when shit hits the fan. I believe that both you and Jim agree with me on that. If not, where am I mistaken?
I may break a few more than you do in a season's time, but they may also break sooner than yours when shit hits the fan. I believe that both you and Jim agree with me on that. If not, where am I mistaken?
#1 Rogue Pilot
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
>
jimrooney
2008/02/06 23:14:48
Eat something else... he copied that design.
A properly constructed Bailey has a stop (a rivet) that prevents this from happening.
How do I know this?... I was one of the guys that pointed out the problem to him (and how a Bailey doesn't have this problem).
So credit where credit is due... the "brilliance" here belongs to Bobby.
<
http://www.liteflite.com.au/ProductsChe ... lease.aspx
On the remaining issue which had not been previously discredited... Apparently not.
--
NEVER TRUST A WEAK LINK!
Expect two things from your weak link:
(1) It will break unexpectedly at the most inopportune time, with no warning adn no indicaiton of a flight problem.
(2) It will hold strong and fast whenever you move into a lockout.
-
Then I switched to the falcon and the birds were singing in tune again. Until the brand new weak link vaporized at about 1000 feet for no apparent reason.
-
At 840 feet I noticed the tug was high and rising so I pushed out a bit to catch up. Broke the weaklink and stalled since I was so nose-high.
-
First try was a notably short flight, with a weak link break moments after lifting from the launch cart. The wind had shifted, so I had a down-wind landing, rolling in. I succeeded in dragging a knee instead of a toe on one side, so I earned a nice strawberry scrape.
-
I got five launches with three full flights on the US. Two weak link breaks. Both were non-issues.
-
Got to Ridgley after 12, late as usual and was one of the last to launch. Broke a weak link. From now on I use a new weak link every time since they're giving us dental floss now.
-
Kristen attached me to the plane and I rose briefly in the air. Pop! My weak link broke. (...The bad part is that sometimes the links just break, for no particular reason.)
-
Just a quick story with good educational value for other tow pilots. Yesterday I was the second of 3 off cart weak link breaks behind a 914 tug. Turbo was kicking in too quick says Bo.
-
I bent one this year when I had a weak link break right off the cart...
-
I had a weak link break at maybe 50 feet. I thought I was going to have to land in the soybeans -- the very tall soybeans -- when I looked at my angle. But, my glider stalled quite dramatically almost instantly (hard not to stall when you have a break), and dove towards the ground (a bit disconcerting from so low).
-
...I hit enough turbulence to break my weak link. #%*&!
-
Steve had a weak link break on his first launch just after leaving the cart and rode it in on the asphault.
-
A second later, we are horrified to see her weak link has broken. We know she has been well prepared, but we want her first flight to be perfect.
-
...but at 400 feet my pussy-##s weak link broke.
-
I had a late start due to a weak link break.
-
Being a "large and tall" pilot (6' and 225lbs) on a big glider, I don't get pushed around as much by thermals...but then again, I'm pushing the weak link that much closer to it's breaking point (since everyone tends to use the same test-strength line for the link).
-
I've only had one weak link break while aerotowing and it happened while I was still very low and over the runway. I was happy that I automatically pulled in as soon as I heard the snap and got slow.
-
One of the more interesting and poinient ones is the smooth air break. Towing up in smooth air, in position and you have a good weaklink... just towing along straight and level, nice and smooth... when the weaklink breaks. There's no appearent reason. No rough air, no rough glider inputs... it just breaks.
-
Broke the weak link at 100' this time. The tow was a little rowdy, but not that bad. Don't know what caused the break.
-
This time the link broke at 900'. Damn.
-
Broke the weak link at 1000'. And it was a fairly mellow tow.
-
I was in line early but had a green tow pilot. My weak link broke after an extremely fast 350 feet.
-
Anyway, on my first tow, Tex entered a thermal at just over 1100 AGL, and I failed to track properly behind him. I got turned away from him (not badly) and as I was about to get back into position the weak link broke at 1200 AGL.
-
I could feel a huge gust hit right as I came off the cart. Uh oh. I was right behind the tug at maybe 100 feet when my link broke. (Kev said yesterday the weak link might have also broken because of the very powerful tug, which throttled back yesterday.)
-
My weak link broke for no obvious reason at ~2,000' as Zack was pulling me in a wide turn to get back into a thermal he had found earlier.
--
>
jimrooney
Greenspun get's used because it's manufactured. It's a common and standard material. You can get it at a fishing store and everyone knows what it is. This seems trivial, but it's again one of those things that looks small, but isn't.
Argue all you like about the validity of it's consistency in manufacturing (I know Tad will), but here's the rub... it has a testing system in place. And it far exceeds anything any non manufactured article could hope to achieve.
<
Yup, the tolerances of the "standard" 130 pound Greenspot loop are truly incredible. How could one possibly improve on a record like that?
Just two things are important here. "Greenspun" is "manufactured" and "it has a testing system in place".
The testing system in place is, of course, "assume that a link blows at 260 pounds of direct tension, skip the bench testing, slap it on every glider that shows up, ignore the fact that it routinely fails under a direct load of anywhere between 63 and 140 pounds, and assume that - if nobody gets killed - it's record can't be improved upon."
>
And it far exceeds anything any non manufactured article could hope to achieve.
<
And if Sunny is using something else with tolerances of around plus or minus five percent - hell, just ignore the extensive data which undermines your position.
>
jimrooney
Find a material that meets/exceeds greenspot in all aspects and you've got something.
Hand made stuff doesn't cut it. Handmade has no quality control and no standards. It is not identifiable.
I've yet to hear anything from anyone that even comes close. If it's out there, bring it on.
Till then, you're stuck with greenspot.
<
>
jimrooney
Sorry Brian, I don't read Tad's posts.
<
Yup, why bother listening to ANYONE when you've known everything worth knowing since age five?
jimrooney
2008/02/06 23:14:48
Eat something else... he copied that design.
A properly constructed Bailey has a stop (a rivet) that prevents this from happening.
How do I know this?... I was one of the guys that pointed out the problem to him (and how a Bailey doesn't have this problem).
So credit where credit is due... the "brilliance" here belongs to Bobby.
<
http://www.liteflite.com.au/ProductsChe ... lease.aspx
On the remaining issue which had not been previously discredited... Apparently not.
--
NEVER TRUST A WEAK LINK!
Expect two things from your weak link:
(1) It will break unexpectedly at the most inopportune time, with no warning adn no indicaiton of a flight problem.
(2) It will hold strong and fast whenever you move into a lockout.
-
Then I switched to the falcon and the birds were singing in tune again. Until the brand new weak link vaporized at about 1000 feet for no apparent reason.
-
At 840 feet I noticed the tug was high and rising so I pushed out a bit to catch up. Broke the weaklink and stalled since I was so nose-high.
-
First try was a notably short flight, with a weak link break moments after lifting from the launch cart. The wind had shifted, so I had a down-wind landing, rolling in. I succeeded in dragging a knee instead of a toe on one side, so I earned a nice strawberry scrape.
-
I got five launches with three full flights on the US. Two weak link breaks. Both were non-issues.
-
Got to Ridgley after 12, late as usual and was one of the last to launch. Broke a weak link. From now on I use a new weak link every time since they're giving us dental floss now.
-
Kristen attached me to the plane and I rose briefly in the air. Pop! My weak link broke. (...The bad part is that sometimes the links just break, for no particular reason.)
-
Just a quick story with good educational value for other tow pilots. Yesterday I was the second of 3 off cart weak link breaks behind a 914 tug. Turbo was kicking in too quick says Bo.
-
I bent one this year when I had a weak link break right off the cart...
-
I had a weak link break at maybe 50 feet. I thought I was going to have to land in the soybeans -- the very tall soybeans -- when I looked at my angle. But, my glider stalled quite dramatically almost instantly (hard not to stall when you have a break), and dove towards the ground (a bit disconcerting from so low).
-
...I hit enough turbulence to break my weak link. #%*&!
-
Steve had a weak link break on his first launch just after leaving the cart and rode it in on the asphault.
-
A second later, we are horrified to see her weak link has broken. We know she has been well prepared, but we want her first flight to be perfect.
-
...but at 400 feet my pussy-##s weak link broke.
-
I had a late start due to a weak link break.
-
Being a "large and tall" pilot (6' and 225lbs) on a big glider, I don't get pushed around as much by thermals...but then again, I'm pushing the weak link that much closer to it's breaking point (since everyone tends to use the same test-strength line for the link).
-
I've only had one weak link break while aerotowing and it happened while I was still very low and over the runway. I was happy that I automatically pulled in as soon as I heard the snap and got slow.
-
One of the more interesting and poinient ones is the smooth air break. Towing up in smooth air, in position and you have a good weaklink... just towing along straight and level, nice and smooth... when the weaklink breaks. There's no appearent reason. No rough air, no rough glider inputs... it just breaks.
-
Broke the weak link at 100' this time. The tow was a little rowdy, but not that bad. Don't know what caused the break.
-
This time the link broke at 900'. Damn.
-
Broke the weak link at 1000'. And it was a fairly mellow tow.
-
I was in line early but had a green tow pilot. My weak link broke after an extremely fast 350 feet.
-
Anyway, on my first tow, Tex entered a thermal at just over 1100 AGL, and I failed to track properly behind him. I got turned away from him (not badly) and as I was about to get back into position the weak link broke at 1200 AGL.
-
I could feel a huge gust hit right as I came off the cart. Uh oh. I was right behind the tug at maybe 100 feet when my link broke. (Kev said yesterday the weak link might have also broken because of the very powerful tug, which throttled back yesterday.)
-
My weak link broke for no obvious reason at ~2,000' as Zack was pulling me in a wide turn to get back into a thermal he had found earlier.
--
>
jimrooney
Greenspun get's used because it's manufactured. It's a common and standard material. You can get it at a fishing store and everyone knows what it is. This seems trivial, but it's again one of those things that looks small, but isn't.
Argue all you like about the validity of it's consistency in manufacturing (I know Tad will), but here's the rub... it has a testing system in place. And it far exceeds anything any non manufactured article could hope to achieve.
<
Yup, the tolerances of the "standard" 130 pound Greenspot loop are truly incredible. How could one possibly improve on a record like that?
Just two things are important here. "Greenspun" is "manufactured" and "it has a testing system in place".
The testing system in place is, of course, "assume that a link blows at 260 pounds of direct tension, skip the bench testing, slap it on every glider that shows up, ignore the fact that it routinely fails under a direct load of anywhere between 63 and 140 pounds, and assume that - if nobody gets killed - it's record can't be improved upon."
>
And it far exceeds anything any non manufactured article could hope to achieve.
<
And if Sunny is using something else with tolerances of around plus or minus five percent - hell, just ignore the extensive data which undermines your position.
>
jimrooney
Find a material that meets/exceeds greenspot in all aspects and you've got something.
Hand made stuff doesn't cut it. Handmade has no quality control and no standards. It is not identifiable.
I've yet to hear anything from anyone that even comes close. If it's out there, bring it on.
Till then, you're stuck with greenspot.
<
>
jimrooney
Sorry Brian, I don't read Tad's posts.
<
Yup, why bother listening to ANYONE when you've known everything worth knowing since age five?
-
theflyingdude
- Posts: 358
- Joined: Thu Jan 06, 2005 11:40 pm
- Location: Cumberland, MD
Re:
Now if that's not the pot calling the kettle black, I don't know what is.Tad Eareckson wrote:>
jimrooney
Sorry Brian, I don't read Tad's posts.
<
Yup, why bother listening to ANYONE when you've known everything worth knowing since age five?
JR
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Re: Weak link question
Okay, a lot of people are throwing around how much knowledge they have related to towing. Let's test it.
You are a pilot with hook-in weight of 190 lbs, flying a 70 lb glider. You are handed a loop of commercially tested greenspot by the flight crew. You are flying standard configuration: bridle to each shoulder, release suspended from the keel.
1. based on the rating of the greenspot, what number of G's will the flight crew tell you the loop is good for?
2. based on Tad's tests, what number of G's is the loop good for?
How many of you can pass this test?
You are a pilot with hook-in weight of 190 lbs, flying a 70 lb glider. You are handed a loop of commercially tested greenspot by the flight crew. You are flying standard configuration: bridle to each shoulder, release suspended from the keel.
1. based on the rating of the greenspot, what number of G's will the flight crew tell you the loop is good for?
2. based on Tad's tests, what number of G's is the loop good for?
How many of you can pass this test?
Brian Vant-Hull
Re: Weak link question
Brian, this discussion to me is only relevant for one scenario. Big guys, the major target group of Tad's futile efforts, with greenspot weak links entering a high line tension lockout and not releasing. I don't give a rat's ass about anything else that could and might and will likely never. So, in that particular scenario, Brian or Jim, if you were in my shoes, would you want something that breaks at 0.8 G, 1+ G or 1.4+ G? If I get an answer to that question from either one of you I will gladly leave this discussion and wait for something new to debate you guys on 
#1 Rogue Pilot
Re: Weak link question
Brian,
While I appreciate your quest for the perfect weaklink, didn't we cover this already? (Again?)
Are we to go down the road of debating the quality standards of greenspot again?
Ok, for review, it doesn't matter.
Why?
Because you have nothing else.
Do I have to review why we don't tow handmade gliders?
Listen we're all perfectly aware that greenspot is not laser calibrated to 130lbs. It's bloody fishing line. Get over it. Are you flying below your perfect numbers as a heavy guy. Yes. Yes you are. Get over it.
Why?
Because it's all you've got.
Why lower numbers? Because your choice is lower or higher... and higher is more dangerous than lower.
Plain and simple. Janni, 1G, but please stay.
Now, my turn.
Name one commercially available strength rated material that can be used as a weaklink OTHER than greenspot.
While I appreciate your quest for the perfect weaklink, didn't we cover this already? (Again?)
Are we to go down the road of debating the quality standards of greenspot again?
Ok, for review, it doesn't matter.
Why?
Because you have nothing else.
Do I have to review why we don't tow handmade gliders?
Listen we're all perfectly aware that greenspot is not laser calibrated to 130lbs. It's bloody fishing line. Get over it. Are you flying below your perfect numbers as a heavy guy. Yes. Yes you are. Get over it.
Why?
Because it's all you've got.
Why lower numbers? Because your choice is lower or higher... and higher is more dangerous than lower.
Plain and simple. Janni, 1G, but please stay.
Now, my turn.
Name one commercially available strength rated material that can be used as a weaklink OTHER than greenspot.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Re: Weak link question
I posted the quiz to point out that most people don't feel comfortable analyzing the situation in the first place. Plus one would think when you loop 130 lb test greenspot you get 260 lbs minus some small amount for wrapping it around a bridle (hiding the knot from direct tension), but most people would be surprised to find that Tad tested the loops to be around 140 lbs. Most professionals don't even know that. And it abrades with time.
It's not kept because it's reliable or even well understood, it's kept because folks recognize it so they feel comfortable.
Tad has posted a site that has plastic strips for weak links, with holes cut in them to decrease the strength as needed. Seems better than the stuff we use now, with more room for adjustment. Made by a company focussed on towing.
I think heavier pilots should have a choice to increase the weak link strength to within the specified 100 lbs below the tug weak link. The links will be more expensive, but also replaced less often.
It's not kept because it's reliable or even well understood, it's kept because folks recognize it so they feel comfortable.
Tad has posted a site that has plastic strips for weak links, with holes cut in them to decrease the strength as needed. Seems better than the stuff we use now, with more room for adjustment. Made by a company focussed on towing.
I think heavier pilots should have a choice to increase the weak link strength to within the specified 100 lbs below the tug weak link. The links will be more expensive, but also replaced less often.
Brian Vant-Hull
Re: Weak link question
It's not kept because it's reliable
There are a couple thousand successful tows that tend to contradict that statement.
I work with a lot of people that would tend to disagree with that.or even well understood
Just because the solo pilot crowd isn't aware, please do not assume this.
One criteria is of course that they are recognizable... to me... not you.
But that's not it. They are kept because they have a huge track record. That's really hard to argue with.
I've yet to hear anyone successfully do so.
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.
Jim
Re: Weak link question
Oh come on, you think the makers of greenspot start with the raw materials? they get stuff from other folks they don't control.
Of course the community has to use something they feel comfortable with, and can't go switching willy nilly. But if something is out there that everyone has access to and it would allow some more control, isn't it worth looking at?
Granted, it's a small company in a niche market that could go belly up any time. I'd prefer something like greenspot that is weaker so a multiple loop method could be used with more room for adjustment. No doubt the towing community has already been through this and settled on the best they could do. But it's worth looking every few years, isn't it?
Anyway, I don't see much more to say unless the tug link can be made stronger.
Of course the community has to use something they feel comfortable with, and can't go switching willy nilly. But if something is out there that everyone has access to and it would allow some more control, isn't it worth looking at?
Granted, it's a small company in a niche market that could go belly up any time. I'd prefer something like greenspot that is weaker so a multiple loop method could be used with more room for adjustment. No doubt the towing community has already been through this and settled on the best they could do. But it's worth looking every few years, isn't it?
Anyway, I don't see much more to say unless the tug link can be made stronger.
Brian Vant-Hull
Re: Weak link question
Agreed, it seems trivial, but it's actually a large difference.
(Notice a trend?)
The difference is when the quality control happens, and to what extent. Commercially available material that's sold as load tested is held to standards. There is a huge difference between a backyard production run and something that's available quite literally around the world. The volume difference is absolutely massive. The quality control sampling is far far greater than whatever a single person, or even a single outfit can muster. It's simply night and day.
See the fishing line isn't being made from raw materials with an assumption of quality. The testing happens after it's produced. And happens on an absolutely massive scale. There is no assumption of quality of the raw materials.
The plastic links are assumed to be made to a certain tolerance and then tested by Bob in very limited quantities. The quality of the raw materials is assumed. Big big difference.
And yep... thanks for pointing out the futility of all this... You're confined to certain parameters (tug's link), so discussing things outside those parameters is pretty darn pointless.
(Notice a trend?)
The difference is when the quality control happens, and to what extent. Commercially available material that's sold as load tested is held to standards. There is a huge difference between a backyard production run and something that's available quite literally around the world. The volume difference is absolutely massive. The quality control sampling is far far greater than whatever a single person, or even a single outfit can muster. It's simply night and day.
See the fishing line isn't being made from raw materials with an assumption of quality. The testing happens after it's produced. And happens on an absolutely massive scale. There is no assumption of quality of the raw materials.
The plastic links are assumed to be made to a certain tolerance and then tested by Bob in very limited quantities. The quality of the raw materials is assumed. Big big difference.
And yep... thanks for pointing out the futility of all this... You're confined to certain parameters (tug's link), so discussing things outside those parameters is pretty darn pointless.
Re: Weak link question
I won, I won!!!Why lower numbers? Because your choice is lower or higher... and higher is more dangerous than lower.
Plain and simple. Janni, 1G
What was your point about nylon vs. dacron in harness suspensions again, Tad?
#1 Rogue Pilot
Re: Weak link question
Jim;
From the website Tad found:
"In 2005, we celebrated the company's 60th anniversary. All these years, our business has been located on the same site in the heart of Munich..."
This company has been manufacturing towing products longer than hang gliding has been in existence. Gee, somebody trusts their products, and its a larger community than hang gliding. Maybe it's time to get less provincial?
Janni - I wouldn't say it's settled that weaker is safer. Try a link that's just enough to lift you partway off the cart then dump you. And do it without wheels. Two opposing safety standards, there's got to be a sweet spot, even if we haven't found a way to know for sure where it is.
From the website Tad found:
"In 2005, we celebrated the company's 60th anniversary. All these years, our business has been located on the same site in the heart of Munich..."
This company has been manufacturing towing products longer than hang gliding has been in existence. Gee, somebody trusts their products, and its a larger community than hang gliding. Maybe it's time to get less provincial?
Janni - I wouldn't say it's settled that weaker is safer. Try a link that's just enough to lift you partway off the cart then dump you. And do it without wheels. Two opposing safety standards, there's got to be a sweet spot, even if we haven't found a way to know for sure where it is.
Brian Vant-Hull
Re: Weak link question
Otto Lilienthal, wasn't he out there back in the day running the hills? I can't recall what airport I was in, there was a replica glider hanging from the ceiling. I wonder if they utilized weak links back then.
Gene
Gene
Re: Weak link question
Fair enough... there you have it then.... grab one of their weaklinks at your appropriate size and dispense with all this drama an all these silly hand made weaklinks.
Those "toast" weaklinks fit all the criteria then?... Tad's still do not, btw... nothing's changed there. So... if Tad really is seeking to improve safety... will he now give up making weaklinks and instead start pushing these?
Jim
Those "toast" weaklinks fit all the criteria then?... Tad's still do not, btw... nothing's changed there. So... if Tad really is seeking to improve safety... will he now give up making weaklinks and instead start pushing these?
Jim
Re: Weak link question
Good enough. I'm done. Sorry for hanging in here for so long, I just wanted to show Tad that if you didn't treat a discussion like a street brawl you could actually make progress. He may actually have more up his sleeve, but now it's his turn.
Brian Vant-Hull
Re: Weak link question
I checked the site out, those are indeed neat. Thanks for finding that, Tad.
I'll be in Germany over Christmas and think I could buy a few of those if there is interest. Let me know.
I'll be in Germany over Christmas and think I could buy a few of those if there is interest. Let me know.
#1 Rogue Pilot
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Brian,
Thanks much for taking the heat off me for a while and greatly amending the rational component of this discussion. Above and beyond the call of duty.
But - as to making PROGRESS?
Did you catch this...
>
RedBaron
So, in that particular (lockout) scenario, Brian or Jim, if you were in my shoes, would you want something that breaks at 0.8 G, 1+ G or 1.4+ G?
<
>
jimrooney
Plain and simple. Janni, 1G
<
>
RedBaron
I won, I won!!!
<
Did you catch that? Want me to play it again? Nah, waste of bandwidth, just go back and reread it a couple of times.
(Let's first remember that that dialog occurred in an exchange that was meant to conceal the fact that neither correspondent had any idea how to calculate the solution to the quiz question you posed and that the one who isn't Janni has no concept of what G loading is to begin with anyway.)
If Janni goes up to the flight line and asks for a weak link to put on the end of his two point bridle, Jim hands him a single loop of Greenspot and says, "Here ya go - One G."
If Karen goes up to the flight line and asks for a weak link to put on the end of her one point bridle, Jim hands her a single loop of Greenspot and says, "Here ya go - One G."
Of course Janni's translates to 0.76 Gs - but that figure is only good before the cart starts rolling. By the time he releases the hold-downs the weak link has degraded and he's down to point five or six.
Karen's loop is 1.4 Gs and tends to stay that 'cause she's got a lot of margin before she's stressing and degrading it.
What I'm trying to do is get a floor defined. I can live with 0.8 (FAA and everybody else) IF, in fact, the 0.8 STAYS 0.8 for the duration of the tow. But I'd like to see 1.0 (just like Jim).
Again - that's the MINIMUM I'm talking about.
But I'm RECOMMENDING folk fly 1.4 - Karen with the magic "1.0" weak link towing off her shoulders.
So - recap - Janni asks Jim if it's safe to go below 1.0. Jim says "NO WAY!" but nevertheless WILL NOT ALLOW him to tow anywhere above half to three quarters of that.
(Bear in mind that a double loop puts him at 1.09.)
So you'd think it was more like - I won, I won!!! - but that would only apply in a strange parallel universe in which two plus two equals four.
Don't worry. This thread won't go on much longer. As soon as this cold spell is over they're not gonna have much trouble finding the storm drain into which I stuffed the body of my court appointed anger management therapist. After they run the DNA analysis on the tissue they'll find underneath her fingernails my story about being attacked by the Black Bear that was raiding my garbage can is going to unravel even faster than that fishing line I used to fly.
Janni,
Enjoy Christmas if you're going back to Germany anyway but don't make a special trip for the weak links - you can order them from Tim of Wings and Wheels in Lakewood, New York. That's how I got a couple of assemblies and the first six of the low end of the insert series a couple of years ago.
However, given the constraints outlined earlier in this discussion, they won't really do anyone much good.
Right now it's a pretty good bet that I'm the only one who understands WHY 'cause it's a pretty good bet I'm the only one who's actually done the testing.
You can probably rely on Jim's clairvoyance to come through once again however. Run it by him and we'll compare/contrast.
Thanks much for taking the heat off me for a while and greatly amending the rational component of this discussion. Above and beyond the call of duty.
But - as to making PROGRESS?
Did you catch this...
>
RedBaron
So, in that particular (lockout) scenario, Brian or Jim, if you were in my shoes, would you want something that breaks at 0.8 G, 1+ G or 1.4+ G?
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jimrooney
Plain and simple. Janni, 1G
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RedBaron
I won, I won!!!
<
Did you catch that? Want me to play it again? Nah, waste of bandwidth, just go back and reread it a couple of times.
(Let's first remember that that dialog occurred in an exchange that was meant to conceal the fact that neither correspondent had any idea how to calculate the solution to the quiz question you posed and that the one who isn't Janni has no concept of what G loading is to begin with anyway.)
If Janni goes up to the flight line and asks for a weak link to put on the end of his two point bridle, Jim hands him a single loop of Greenspot and says, "Here ya go - One G."
If Karen goes up to the flight line and asks for a weak link to put on the end of her one point bridle, Jim hands her a single loop of Greenspot and says, "Here ya go - One G."
Of course Janni's translates to 0.76 Gs - but that figure is only good before the cart starts rolling. By the time he releases the hold-downs the weak link has degraded and he's down to point five or six.
Karen's loop is 1.4 Gs and tends to stay that 'cause she's got a lot of margin before she's stressing and degrading it.
What I'm trying to do is get a floor defined. I can live with 0.8 (FAA and everybody else) IF, in fact, the 0.8 STAYS 0.8 for the duration of the tow. But I'd like to see 1.0 (just like Jim).
Again - that's the MINIMUM I'm talking about.
But I'm RECOMMENDING folk fly 1.4 - Karen with the magic "1.0" weak link towing off her shoulders.
So - recap - Janni asks Jim if it's safe to go below 1.0. Jim says "NO WAY!" but nevertheless WILL NOT ALLOW him to tow anywhere above half to three quarters of that.
(Bear in mind that a double loop puts him at 1.09.)
So you'd think it was more like - I won, I won!!! - but that would only apply in a strange parallel universe in which two plus two equals four.
Don't worry. This thread won't go on much longer. As soon as this cold spell is over they're not gonna have much trouble finding the storm drain into which I stuffed the body of my court appointed anger management therapist. After they run the DNA analysis on the tissue they'll find underneath her fingernails my story about being attacked by the Black Bear that was raiding my garbage can is going to unravel even faster than that fishing line I used to fly.
Janni,
Enjoy Christmas if you're going back to Germany anyway but don't make a special trip for the weak links - you can order them from Tim of Wings and Wheels in Lakewood, New York. That's how I got a couple of assemblies and the first six of the low end of the insert series a couple of years ago.
However, given the constraints outlined earlier in this discussion, they won't really do anyone much good.
Right now it's a pretty good bet that I'm the only one who understands WHY 'cause it's a pretty good bet I'm the only one who's actually done the testing.
You can probably rely on Jim's clairvoyance to come through once again however. Run it by him and we'll compare/contrast.
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Danny Brotto
- Posts: 709
- Joined: Mon Feb 14, 2005 9:29 pm
Re: Weak link question
My glider port uses Tost weak link rig. I tow with one just about every weekend so I’m familiar with it. They are really not for “individual” use. The entire rig is metal and weighs a good bit. It’s ment to go inline between the tug and the glider not within the bridle. I would want it to be well in font of me too so as to not get whacked with all that metal flinging around. The weak-link itself is encased between two slabs of metal.
We used to use a length of polypro line; essentially the entire line was the weak link. We found that after a weekend’s of use the strength was severely degraded by abrasion. We moved over the Tost system that uses a strong line that’s resistant to abrasion coupled with the Tost weak link assembly. Our weak link sports a one-size-fits-all break strength within the specifications of the FARs.
We do have a Sparrowhawk ultralight glider and we uses his own lighter-weight weak link.
Danny Brotto
We used to use a length of polypro line; essentially the entire line was the weak link. We found that after a weekend’s of use the strength was severely degraded by abrasion. We moved over the Tost system that uses a strong line that’s resistant to abrasion coupled with the Tost weak link assembly. Our weak link sports a one-size-fits-all break strength within the specifications of the FARs.
We do have a Sparrowhawk ultralight glider and we uses his own lighter-weight weak link.
Danny Brotto