Our weak links are not ideal, and I appreciate Tad's efforts to improve our towing safety. These efforts have also included the types of releases we use and their location.
I practiced releasing using varied types of release under load (on the ground) at Highland this year, and found it very educational. When pro-towing the method the pilot uses to release can be very important (something I'd never realized, since I've -- knock on wood - never locked out while pro-towing). I found that the only way to release under strong loads (with either curved or straight pin releases) was to grab the TOP of the barrel instead of just grasping around its sides.
But about the weak links.
My husband, Paul has suffered more weak link breaks than I have, which is certainly due to his weight. (At least that's his excuse. Heeheehee. Paul told me to put in this line.) I have broken one in the last two years, with LOTS of tows.
Tad gave Paul a couple of HIS links while we were at the ECCs this year. Paul used them happily ( without any situation that might cause a problem) until one day at Zapata in rough air while he was attempting to adjust his VG. Paul locked out badly and the link didn't break. The double weak-link attached to the tug plane BROKE because the forces were so extreme. Russell quoted afterward that he'd never had his tail pulled around so violently. Luckily, Paul's glider was not stressed to the point of failure, and Paul was able to drop the rope and landed safely.
My only point here is that Tad's releases have not been extensively tested, and at least in my experience with them, are not safe.
I just don't want pilots to think that his weak links are entirely the answer. Tad is very smart, and is trying to address the problems he sees, so he should get kudos for that. But be very careful before you buy into the "great-new-weak-link-thing."
Lauren
Weak link question
Moderator: CHGPA BOD
Re: Weak link question
That's a very good point: maybe the purpose of the weak link is to set an upper limit on how much force the tug is willing to tolerate, which has nothing to do with the mass on the other end of the line. This would explain one size fits all.
Theory is only as good as the initial assumptions, and in this discussion all assumptions have been directed towards the glider end of the rope.
Theory is only as good as the initial assumptions, and in this discussion all assumptions have been directed towards the glider end of the rope.
Brian Vant-Hull
Re: Weak link question
Are you suggesting to use 2 tug weak links on both ends of the line? I think the purpose of the weak link is to be just strong enough so it won't break all the time. That's exactly what I have. It may and will not safe me from every lockout situation (especially where line tension is irrelevant), but if disintegration of my glider is the alternative I'll be very happy with it.That's a very good point: maybe the purpose of the weak link is to set an upper limit on how much force the tug is willing to tolerate, which has nothing to do with the mass on the other end of the line. This would explain one size fits all.
Theory in this discussion has also been based on the assumption that every pilot always has time to get off tow before things get sour. Those who fail areTheory is only as good as the initial assumptions, and in this discussion all assumptions have been directed towards the glider end of the rope.
. Thanks Tad. I had a lot of fun with you. Stay tuned for my lockout experiments using 0.5 G weak links next season.either incompetent or brain dead or, as is the usual such case, some combination of the two
#1 Rogue Pilot
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Janni,
>
I think there are dangers to increasing their strength and I think there are dangers to flying with understrength weak links as well. It all depends on what risks you're more comfortable taking.
<
The risk you're more comfortable taking is flying with a release that you cannot be sure will be accessible and may not work in an emergency. The safety margin you have already decided to discard is so wide it makes all discussion of weak link strength irrelevant.
>
What you mean here is staying on tow is always safer than landing (you don't climb in a lockout all that great), and that's nonsense as well.
<
No. I meant what I said. Climbing out is ALWAYS safer than landing.
And - yes - you can climb just fine in a lockout. Since you can't ask Rob Kells about this, try running it by John Dullahan.
>
Irrelevant, weak links don't create line tension.
<
I didn't say they created tension. What I'm trying to get you to understand is that if you need more tension than the weak link can transmit you don't get ANY tension. Do you understand that?
>
Perhaps I found the sweet spot?
<
With respect to what you're trying to do - which is dial in a strength which can make decisions for you and supersede the role of the release - THERE IS NO SUCH THING AS A SWEET SPOT.
Jim,
What results did you get for the two, three, and four strand weak link strength tests?
>
In the tandem setup, the "weaklink" in the system is at the tug end, not the glider.
<
So does the tandem glider always end up with the rope when a weak link pops?
>
Paul found this out the hard way in Texas.
<
Carlos found out you can get the rope locking out behind a Dragonfly with a two strander at his end. How do you explain this?
>
Ask yourself... are you willing to bet your life on your theory?
<
Janni's willing to bet his life on the theory that his weak link fail in time to keep him from slamming in. Is this a theory to which you also subscribe, despite all the fatality reports supporting another conclusion?
Lauren,
>
I practiced releasing using varied types of release under load (on the ground) at Highland this year, and found it very educational.
<
At the ECC in June I had my test rig configured to allow release actuation under loads up to 388 pounds. I recall Paul taking a spin but not you.
Lotsa other people checked things out and, whereas most had no trouble dumping max load (equivalent to 776 pounds of tow line tension) using only their thumbs and index fingers on my straight pin barrel release, most where unable to budge the curved pin Bailey without prolonged and/or repeated efforts under HALF (194 pounds) the load.
Mark Gregor - age seven late this summer - was also able to dump 388 pounds off the straight pin (albeit with more time and effort than I had hoped).
>
I found that the only way to release under strong loads (with either curved or straight pin releases) was to grab the TOP of the barrel instead of just grasping around its sides.
<
I think Brian can attest that you can blow one of my straight pins under twice the max load anyone's gonna experience in the air in your sleep no matter how you grasp the barrel (suitable for ages ten and up).
>
Tad gave Paul a couple of HIS links while we were at the ECCs this year.
<
Tad recommended and gave Paul a couple of Paul 1.4 G weak links which, to the best of my recollection, limited tow line tension to 420 pounds. Paul could have (and still can) requested weak links of any G rating he wanted.
>
Russell quoted afterward that he'd never had his tail pulled around so violently.
<
Russell determined the violence with which he was willing to have his tail pulled around when he selected the weak link strength for the front end.
>
Luckily, Paul's glider was not stressed to the point of failure...
<
Luck didn't have squat to do with it. Regardless of what was on the front end - which probably failed twenty pounds before the back would have - the glider was stressed to under three Gs (Paul's contribution plus the line tension immediately prior to weak link failure). Hang gliders are good for a minimum of twice that.
The weak link system did EXACTLY what it was supposed to.
The action was violent - It's supposed to be. It's not supposed to be the routine non event to which we've all grown so accustomed. He blew at 1.33 Gs. If Karen tows one point using a one size fits aller she blows at 1.40.
The weak link system is ONLY supposed to protect the planes. The planes were not damaged.
Note also that USHPA defines the upper weak link limit at 2.0 Gs. I gave Paul a 0.6 G / 180 pound margin. If I was out of line then USHPA is WAY out of line.
Paul got the rope 'cause the tug isn't allowing him to operate within established safety standards.
>
Tad's releases have not been extensively tested...
<
I don't know if you meant to say "releases" or "weak links". In any case... They HAVE - in fact - been VERY EXTENSIVELY tested. The summaries have been available online for the better part of a couple of years and the raw data will be provided upon request. Do you know of any other designs for which you can find such data?
>
...and at least in my experience with them, are not safe.
<
Based on what?
>
But be very careful before you buy into the "great-new-weak-link-thing."
<
If you're flying, you've already bought into something. And what virtually everyone has bought into was someone's unqualified say-so.
And with respect to weak links. What virtually everyone as bought into is a magical loop of Greenspot that EVERY solo pilot is told will put him or her at 1.0 Gs.
Brian,
As I've said before - THE TUG IS THERE TO ACCOMMODATE THE GLIDER. It needs - AT THE BARE MINIMUM - to be able to allow me to fly at a weak link rating as good as Karen's.
There is no more THEORY behind the way we've been doing weak links than there is behind using curved pins in barrel releases or mounting release actuators on downtubes. It's all STUPIDITY based.
Do me a favor...
Go back to:
http://www.questairforce.com/aero.html
Read what it says about solo weak links.
Think about it this time. Pretend you're a high school physics teacher evaluating a science project.
THAT'S WHY WE'RE DOING THINGS THE WAY WE ARE - NOT BECAUSE THERE'S INTELLIGENT LIFE ON THIS PLANET.
Janni,
>
Theory in this discussion has also been based on the assumption that every pilot always has time to get off tow before things get sour.
<
Your theory is based on the assumption that:
1. A weak link can be dialed in to prevent you from slamming in; and
2. You will never be in a situation such as Danny was and in need of tension to pull you out of trouble.
Good luck.
>
Stay tuned for my lockout experiments using 0.5 G weak links next season.
<
This winter I'm gonna put a lot of effort into making the use of 0.5 G weak links non compliant with the USHPA SOPs and thus illegal under the terms of FAA Aero Tow Exemption #4144.
If I fail and the folks at Highland are dumb enough to let you pursue your Holy Grail I'll only be able to request that you don't gum up the works during the soaring windows any more that the riduculous extent to which they are now. Believe it or not - I like to have an opportunity to fly every once in a great while.
By the way - at 0.5 Gs you're not even gonna be able to get the cart rolling.
>
I think there are dangers to increasing their strength and I think there are dangers to flying with understrength weak links as well. It all depends on what risks you're more comfortable taking.
<
The risk you're more comfortable taking is flying with a release that you cannot be sure will be accessible and may not work in an emergency. The safety margin you have already decided to discard is so wide it makes all discussion of weak link strength irrelevant.
>
What you mean here is staying on tow is always safer than landing (you don't climb in a lockout all that great), and that's nonsense as well.
<
No. I meant what I said. Climbing out is ALWAYS safer than landing.
And - yes - you can climb just fine in a lockout. Since you can't ask Rob Kells about this, try running it by John Dullahan.
>
Irrelevant, weak links don't create line tension.
<
I didn't say they created tension. What I'm trying to get you to understand is that if you need more tension than the weak link can transmit you don't get ANY tension. Do you understand that?
>
Perhaps I found the sweet spot?
<
With respect to what you're trying to do - which is dial in a strength which can make decisions for you and supersede the role of the release - THERE IS NO SUCH THING AS A SWEET SPOT.
Jim,
What results did you get for the two, three, and four strand weak link strength tests?
>
In the tandem setup, the "weaklink" in the system is at the tug end, not the glider.
<
So does the tandem glider always end up with the rope when a weak link pops?
>
Paul found this out the hard way in Texas.
<
Carlos found out you can get the rope locking out behind a Dragonfly with a two strander at his end. How do you explain this?
>
Ask yourself... are you willing to bet your life on your theory?
<
Janni's willing to bet his life on the theory that his weak link fail in time to keep him from slamming in. Is this a theory to which you also subscribe, despite all the fatality reports supporting another conclusion?
Lauren,
>
I practiced releasing using varied types of release under load (on the ground) at Highland this year, and found it very educational.
<
At the ECC in June I had my test rig configured to allow release actuation under loads up to 388 pounds. I recall Paul taking a spin but not you.
Lotsa other people checked things out and, whereas most had no trouble dumping max load (equivalent to 776 pounds of tow line tension) using only their thumbs and index fingers on my straight pin barrel release, most where unable to budge the curved pin Bailey without prolonged and/or repeated efforts under HALF (194 pounds) the load.
Mark Gregor - age seven late this summer - was also able to dump 388 pounds off the straight pin (albeit with more time and effort than I had hoped).
>
I found that the only way to release under strong loads (with either curved or straight pin releases) was to grab the TOP of the barrel instead of just grasping around its sides.
<
I think Brian can attest that you can blow one of my straight pins under twice the max load anyone's gonna experience in the air in your sleep no matter how you grasp the barrel (suitable for ages ten and up).
>
Tad gave Paul a couple of HIS links while we were at the ECCs this year.
<
Tad recommended and gave Paul a couple of Paul 1.4 G weak links which, to the best of my recollection, limited tow line tension to 420 pounds. Paul could have (and still can) requested weak links of any G rating he wanted.
>
Russell quoted afterward that he'd never had his tail pulled around so violently.
<
Russell determined the violence with which he was willing to have his tail pulled around when he selected the weak link strength for the front end.
>
Luckily, Paul's glider was not stressed to the point of failure...
<
Luck didn't have squat to do with it. Regardless of what was on the front end - which probably failed twenty pounds before the back would have - the glider was stressed to under three Gs (Paul's contribution plus the line tension immediately prior to weak link failure). Hang gliders are good for a minimum of twice that.
The weak link system did EXACTLY what it was supposed to.
The action was violent - It's supposed to be. It's not supposed to be the routine non event to which we've all grown so accustomed. He blew at 1.33 Gs. If Karen tows one point using a one size fits aller she blows at 1.40.
The weak link system is ONLY supposed to protect the planes. The planes were not damaged.
Note also that USHPA defines the upper weak link limit at 2.0 Gs. I gave Paul a 0.6 G / 180 pound margin. If I was out of line then USHPA is WAY out of line.
Paul got the rope 'cause the tug isn't allowing him to operate within established safety standards.
>
Tad's releases have not been extensively tested...
<
I don't know if you meant to say "releases" or "weak links". In any case... They HAVE - in fact - been VERY EXTENSIVELY tested. The summaries have been available online for the better part of a couple of years and the raw data will be provided upon request. Do you know of any other designs for which you can find such data?
>
...and at least in my experience with them, are not safe.
<
Based on what?
>
But be very careful before you buy into the "great-new-weak-link-thing."
<
If you're flying, you've already bought into something. And what virtually everyone has bought into was someone's unqualified say-so.
And with respect to weak links. What virtually everyone as bought into is a magical loop of Greenspot that EVERY solo pilot is told will put him or her at 1.0 Gs.
Brian,
As I've said before - THE TUG IS THERE TO ACCOMMODATE THE GLIDER. It needs - AT THE BARE MINIMUM - to be able to allow me to fly at a weak link rating as good as Karen's.
There is no more THEORY behind the way we've been doing weak links than there is behind using curved pins in barrel releases or mounting release actuators on downtubes. It's all STUPIDITY based.
Do me a favor...
Go back to:
http://www.questairforce.com/aero.html
Read what it says about solo weak links.
Think about it this time. Pretend you're a high school physics teacher evaluating a science project.
THAT'S WHY WE'RE DOING THINGS THE WAY WE ARE - NOT BECAUSE THERE'S INTELLIGENT LIFE ON THIS PLANET.
Janni,
>
Theory in this discussion has also been based on the assumption that every pilot always has time to get off tow before things get sour.
<
Your theory is based on the assumption that:
1. A weak link can be dialed in to prevent you from slamming in; and
2. You will never be in a situation such as Danny was and in need of tension to pull you out of trouble.
Good luck.
>
Stay tuned for my lockout experiments using 0.5 G weak links next season.
<
This winter I'm gonna put a lot of effort into making the use of 0.5 G weak links non compliant with the USHPA SOPs and thus illegal under the terms of FAA Aero Tow Exemption #4144.
If I fail and the folks at Highland are dumb enough to let you pursue your Holy Grail I'll only be able to request that you don't gum up the works during the soaring windows any more that the riduculous extent to which they are now. Believe it or not - I like to have an opportunity to fly every once in a great while.
By the way - at 0.5 Gs you're not even gonna be able to get the cart rolling.
Re: Weak link question
As I'm sure I'm referred to in Tad's post, I'd just like to remind our viewers that he's on my "foe" list and I'll neither be reading nor responding to his post.
Jim
Jim
-
Lauren Tjaden
- Posts: 371
- Joined: Tue Mar 01, 2005 6:27 pm
Re: Weak link question
Regarding Tad's last post: I spent at least half an hour on a quiet day before the ECC (I don't think Tad was there)testing releases under load. What I found personally was the straight pin was a little easier than the curved, but it was not really easy. I was shocked at hard both were. I frankly thought it was great training, because to figure out how to get those things to release under pressure might have taken several lifetimes (literally) to figure out in the air. (When I closed my hand over the top of the barrel they would release. I never even realized before that my habit was to just grab the sides of the barrel.)
The weak link Tad gave Paul did not break under pressure that was so violent that it broke the TUG'S weak link. It was a pretty scary incident. (Sometimes regular weak links do not break when they should, either. However, the very first time this particular link should have broken it failed to do so. And yes, when the glider yanks the plane sideways, the link should break. Never did.)
There are also certainly cases where a link breaking early can be dangerous, and it is always a hassle. For heavier pilots on big gliders the standard weak links are a little light. But make no mistake that being stuck to the plane is something that can also be fatal.
When making your choice about this, remember that the tow park has a say in it. Many will not allow you to use anything other than a standard weak link. At many meets your link is checked before you are allowed to launch. Pilots sometimes beef up their links in order to avoid having to relaunch, with sometimes tragic results.
BTW, the tandem at Quest certainly has a weak link on the glider side. As far as I know, all of them do.
Again, Tad is smart, and no one can accuse him of being apathetic. His desire to improve safety should be applauded. However, these are simply my personal experiences.
Lauren
The weak link Tad gave Paul did not break under pressure that was so violent that it broke the TUG'S weak link. It was a pretty scary incident. (Sometimes regular weak links do not break when they should, either. However, the very first time this particular link should have broken it failed to do so. And yes, when the glider yanks the plane sideways, the link should break. Never did.)
There are also certainly cases where a link breaking early can be dangerous, and it is always a hassle. For heavier pilots on big gliders the standard weak links are a little light. But make no mistake that being stuck to the plane is something that can also be fatal.
When making your choice about this, remember that the tow park has a say in it. Many will not allow you to use anything other than a standard weak link. At many meets your link is checked before you are allowed to launch. Pilots sometimes beef up their links in order to avoid having to relaunch, with sometimes tragic results.
BTW, the tandem at Quest certainly has a weak link on the glider side. As far as I know, all of them do.
Again, Tad is smart, and no one can accuse him of being apathetic. His desire to improve safety should be applauded. However, these are simply my personal experiences.
Lauren
Re: Weak link question
my dearest tad,
over the course of our online affair we've experienced many ups and downs, consistent with any passionate relationship.
albeit with a few lapses, it's apparent that you've been attempting to live clean and sober and you must certainly see that the results have been beneficial to both you, your cause and those who so desperately have attempted to be a part of your life, a part of your quest.
people obviously are feeling safer about approaching you, particularly when in disagreement.
so if i can offer you these words of encouragement at this critical juncture - don't fricking blow it now! keep on keepin on.
love and kisses,
gary D
over the course of our online affair we've experienced many ups and downs, consistent with any passionate relationship.
albeit with a few lapses, it's apparent that you've been attempting to live clean and sober and you must certainly see that the results have been beneficial to both you, your cause and those who so desperately have attempted to be a part of your life, a part of your quest.
people obviously are feeling safer about approaching you, particularly when in disagreement.
so if i can offer you these words of encouragement at this critical juncture - don't fricking blow it now! keep on keepin on.
love and kisses,
gary D
Re: Weak link question
oh yeah, best if read with the voice of Barry White (deep soulful bass r&b singer) in mind.
garyD
garyD
Re: Weak link question
You are right. My mistake. FYI, I never had any problems catching up to the tug when I got too low and slow using understrength weak links.I didn't say they created tension. What I'm trying to get you to understand is that if you need more tension than the weak link can transmit you don't get ANY tension. Do you understand that?
As did the guy in the video and as did Paul when he almost stretched the sail of his $10,000 glider to the point where he'd have to consider competing with Falcon pilots.And - yes - you can climb just fine in a lockout.
...and belong in the trash after thatthe glider was stressed to under three Gs (Paul's contribution plus the line tension immediately prior to weak link failure). Hang gliders are good for a minimum of twice that.
Thanks. I'm looking forward to collaborating with you.This winter I'm gonna put a lot of effort into making the use of 0.5 G weak links non compliant with the USHPA SOPs and thus illegal under the terms of FAA Aero Tow Exemption #4144.
#1 Rogue Pilot
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Janni,
>
FYI, I never had any problems catching up to the tug when I got too low and slow using understrength weak links.
<
If you have every had a weak link - understrength by definition - pop for no other apparent reason - as I'm rather certain you have - then it doesn't matter whether or not you've had one break in a potentially dangerous situation. You are vulnerable and operating in dice roll mode (which seems to be your style of choice anyway).
>
As did the guy in the video...
<
The guy in the video was NOT climbing in a lockout. The guy in the video decided he wanted to get as good a view as possible in as short a time as possible. Upon attaining that goal his remaining options were to go straight down or down with one of two sidewise options. Since the guy was obviously not a control freak he allowed the decision to be made for him.
Have you noticed that you seem to be the only person on the planet who considers this near fatality to be a weak link issue?
This - of course - would be consistent with your inability to recognize that you had a problem in your own near fatal situation which resulted from your own total failure to control the glider in totally benign conditions.
You, Tog, and MG oughta get together for a few beers and some "There I was!" stories. I'm sure the three of you will be able to keep each other entertained for about 36 hours non stop. And you haven't even commenced your 0.5 G experiments yet
>
...and as did Paul when he almost stretched the sail of his $10,000 glider to the point where he'd have to consider competing with Falcon pilots.
<
Bullshit. You seem to have a problem discarding data inconvenient to your hypothesis and inventing it when it suits you.
>
...and belong in the trash after that
<
Also bullshit. And of what relevance in any case?
How 'bout an alternative approach...
1. Learn to recognize and understand what the genuine experts in this field are saying before you challenge it and experiment with square wheels.
2. Learn to recognize incompetence as you observe and commit it.
3. Bring your equipment up to minimal standards.
4. Learn to fly.
5. Adhere to the above order.
Brian,
>
The blanket statement that weak links do nothing to protect the pilot may not be strictly correct, just mostly true.
<
>
We lighter pilots have been towing with proportionally stronger links for years, and I think we've been happier.
<
>
Yes, there are dangers to increasing the weak length strength, but since I'm concentrating so hard when near the ground and I have my finger literally on the release, I can deal with it faster than the link can.
<
You keep pinging in real close to the target but you're not hitting it and you NEVER will as long as you're thinking of a weak link as having anything to do with the safety of the PILOT.
I'm gonna skip the quotes this time but... Freeman, Kroop, Caruk, Hewett, Danny...
Within the limit of 2.0 - THERE ARE NO DANGERS TO INCREASING THE WEAK LENGTH STRENGTH.
The weak link is there to keep the glider from breaking and YOU CAN'T BREAK A GLIDER WITH A 2.0 G WEAK LINK.
It's only when you start compromising on the definition of a weak link and try to use it as compensation for an unqualified pilot do you start making it dangerous.
Janni was allowed to slip through the cracks. He had no business being on the end of a tow line by himself at his skill level and NOBODY has any business getting on a cart with a release such as that.
His weak link broke and he lucked out. If he does the same thing a second time is weak link will break and he'll luck out. The third time he does it he's gonna get killed.
You put enough people in the air you're gonna kill some of them. If you gotta kill folk you wanna kill the ones who aren't doing their jobs. You don't wanna kill the ones who were doing everything right.
If you try to dumb the weak link down to allow Janni to survive two extra flights he shouldn't have - then you kill Bob by robbing him of the ability to exercise control of his situation. And if you do that you've subverted the course of Darwinian evolution.
Let's remove the K2 fiasco from the equation and assume that you've had an unneeded/undesired weak link break at some other point in your flying career. That being the case - you got killed (as I indicated Janni).
You put yourself in the low level Bob oscillation (or Danny tip stalled) scenario, that weak link WILL pop at the WORST POSSIBLE instant, and you WILL cartwheel.
And your last thoughts will be...
"HOW COULD I HAVE BEEN SO -STUPID-! I never needed a weak link in the first place 'cause I was a halfway competent tow pilot, I had a good release, and I was never in a situation in which I couldn't beat the weak link if necessary. If only I had been able to hold onto the tow it would have pulled me out of trouble and I'da been fine."
THAT'S why I fly 1.4 and that's why - if I'm ever in such a situation and something on the other end of the line pops or is released - my last thoughts will NOT be kind ones.
>
FYI, I never had any problems catching up to the tug when I got too low and slow using understrength weak links.
<
If you have every had a weak link - understrength by definition - pop for no other apparent reason - as I'm rather certain you have - then it doesn't matter whether or not you've had one break in a potentially dangerous situation. You are vulnerable and operating in dice roll mode (which seems to be your style of choice anyway).
>
As did the guy in the video...
<
The guy in the video was NOT climbing in a lockout. The guy in the video decided he wanted to get as good a view as possible in as short a time as possible. Upon attaining that goal his remaining options were to go straight down or down with one of two sidewise options. Since the guy was obviously not a control freak he allowed the decision to be made for him.
Have you noticed that you seem to be the only person on the planet who considers this near fatality to be a weak link issue?
This - of course - would be consistent with your inability to recognize that you had a problem in your own near fatal situation which resulted from your own total failure to control the glider in totally benign conditions.
You, Tog, and MG oughta get together for a few beers and some "There I was!" stories. I'm sure the three of you will be able to keep each other entertained for about 36 hours non stop. And you haven't even commenced your 0.5 G experiments yet
>
...and as did Paul when he almost stretched the sail of his $10,000 glider to the point where he'd have to consider competing with Falcon pilots.
<
Bullshit. You seem to have a problem discarding data inconvenient to your hypothesis and inventing it when it suits you.
>
...and belong in the trash after that
<
Also bullshit. And of what relevance in any case?
How 'bout an alternative approach...
1. Learn to recognize and understand what the genuine experts in this field are saying before you challenge it and experiment with square wheels.
2. Learn to recognize incompetence as you observe and commit it.
3. Bring your equipment up to minimal standards.
4. Learn to fly.
5. Adhere to the above order.
Brian,
>
The blanket statement that weak links do nothing to protect the pilot may not be strictly correct, just mostly true.
<
>
We lighter pilots have been towing with proportionally stronger links for years, and I think we've been happier.
<
>
Yes, there are dangers to increasing the weak length strength, but since I'm concentrating so hard when near the ground and I have my finger literally on the release, I can deal with it faster than the link can.
<
You keep pinging in real close to the target but you're not hitting it and you NEVER will as long as you're thinking of a weak link as having anything to do with the safety of the PILOT.
I'm gonna skip the quotes this time but... Freeman, Kroop, Caruk, Hewett, Danny...
Within the limit of 2.0 - THERE ARE NO DANGERS TO INCREASING THE WEAK LENGTH STRENGTH.
The weak link is there to keep the glider from breaking and YOU CAN'T BREAK A GLIDER WITH A 2.0 G WEAK LINK.
It's only when you start compromising on the definition of a weak link and try to use it as compensation for an unqualified pilot do you start making it dangerous.
Janni was allowed to slip through the cracks. He had no business being on the end of a tow line by himself at his skill level and NOBODY has any business getting on a cart with a release such as that.
His weak link broke and he lucked out. If he does the same thing a second time is weak link will break and he'll luck out. The third time he does it he's gonna get killed.
You put enough people in the air you're gonna kill some of them. If you gotta kill folk you wanna kill the ones who aren't doing their jobs. You don't wanna kill the ones who were doing everything right.
If you try to dumb the weak link down to allow Janni to survive two extra flights he shouldn't have - then you kill Bob by robbing him of the ability to exercise control of his situation. And if you do that you've subverted the course of Darwinian evolution.
Let's remove the K2 fiasco from the equation and assume that you've had an unneeded/undesired weak link break at some other point in your flying career. That being the case - you got killed (as I indicated Janni).
You put yourself in the low level Bob oscillation (or Danny tip stalled) scenario, that weak link WILL pop at the WORST POSSIBLE instant, and you WILL cartwheel.
And your last thoughts will be...
"HOW COULD I HAVE BEEN SO -STUPID-! I never needed a weak link in the first place 'cause I was a halfway competent tow pilot, I had a good release, and I was never in a situation in which I couldn't beat the weak link if necessary. If only I had been able to hold onto the tow it would have pulled me out of trouble and I'da been fine."
THAT'S why I fly 1.4 and that's why - if I'm ever in such a situation and something on the other end of the line pops or is released - my last thoughts will NOT be kind ones.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
jimrooney:
>
2008/11/20 22:25:38
Keep fighting Janni. He'll never listen to you, but it's entertaining to watch ;)
<
>
2008/11/21 08:01:04
As I'm sure I'm referred to in Tad's post, I'd just like to remind our viewers that he's on my "foe" list and I'll neither be reading nor responding to his post.
<
Ya gotta love the irony.
>
2008/11/20 22:25:38
Keep fighting Janni. He'll never listen to you, but it's entertaining to watch ;)
<
>
2008/11/21 08:01:04
As I'm sure I'm referred to in Tad's post, I'd just like to remind our viewers that he's on my "foe" list and I'll neither be reading nor responding to his post.
<
Ya gotta love the irony.
Re: Weak link question
Tad -
You keep saying there's been 40,000 incident free tows at Ridgely, then turn around and say the present weak link system will kill people. Obviously you don't value consistency or you wouldn't be trying to change things.
You keep saying there's been 40,000 incident free tows at Ridgely, then turn around and say the present weak link system will kill people. Obviously you don't value consistency or you wouldn't be trying to change things.
Brian Vant-Hull
Re: Weak link question
Nail on the head Brian!
The simple fact is this. The only reason anyone even gives Tad the time of day is that they want to believe him. Why? Because they don't like to be inconvenienced by a weaklink break. That's it.
Sure, everyone digs around for other reasons to believe, but at the heart of it, it's convenience.
No one is actually scared to fly with a standard weaklink. They may say they are, but deep down inside, they're not. BTW, this weaklink as a lifeline comment... any tow pilot that takes you over something you can't get out from should be shot. It is one of the cardinal rules of towing. Again, "I wana believe" rationalization.
Tad loves to speak of himself as a scientifically minded person. Yet he ignores a data pool that is at minimum three orders of magnitude higher than his. It is thus that I ignore him.
Jim
The simple fact is this. The only reason anyone even gives Tad the time of day is that they want to believe him. Why? Because they don't like to be inconvenienced by a weaklink break. That's it.
Sure, everyone digs around for other reasons to believe, but at the heart of it, it's convenience.
No one is actually scared to fly with a standard weaklink. They may say they are, but deep down inside, they're not. BTW, this weaklink as a lifeline comment... any tow pilot that takes you over something you can't get out from should be shot. It is one of the cardinal rules of towing. Again, "I wana believe" rationalization.
Tad loves to speak of himself as a scientifically minded person. Yet he ignores a data pool that is at minimum three orders of magnitude higher than his. It is thus that I ignore him.
Jim
Re: Weak link question
i'm pretty sure about the veracity of this, i could be wrong (could have used veracity inappropriately as well but hey, screw it). does anyone remember when all the best scientific minds with all the then current scientific theories and engineering info and studies and all that stuff . . . remember when science was pretty much certain that bumble bees couldn't fly? damned things kept on flying anyhow. i'm just saying.
garyD
could be that was one of them urban science myths and i've been out of the lab for a long time.
garyD
could be that was one of them urban science myths and i've been out of the lab for a long time.
Re: Weak link question
jheez what was i thinking. i left my password and stuff out where my dog found it. i'm on the other line right now with purina and my credit card company. so uhm how 'bout we just say that post never happened (you know, like always).
garyD
damn dog, always getting me in trouble. used to eat my homework too.
garyD
damn dog, always getting me in trouble. used to eat my homework too.
Re: Weak link question
I think Tad has a point that we could perhaps scale up the links for heavier pilots, and convenience keeps us from doing so.
But there's perhaps an upper limit for situations not well described by theory, and I get annoyed when someone professes to know the entire truth and everyone else must be idiots. (Okay, I may have once said Bernoulli's principle has nothing to do with wings, but I was willing to modify that to say it's not a simple connection and you're better off without it for normal discussion and quick calculation. And I never intentionally insulted anyone's intelligence the way Tad continues to.) I think he's largely right, but I'll back down and modify when presented with new evidence.
Right now I'm still digesting the idea that the tug doesn't want to be yanked in strange directions by more force than a standard weak link will allow. The link on the tug end may be there to protect tug equipment from breaking during a bridle wrap, the one on the glider end may be there to prevent the tug from nosing into the ground. The poor tug has to watch everything in a 4 inch mirror, for pete's sake.
It's good to discuss and make sure we know exactly why things are there, but I'd really like to see a little less god complex from a certain someone.
But there's perhaps an upper limit for situations not well described by theory, and I get annoyed when someone professes to know the entire truth and everyone else must be idiots. (Okay, I may have once said Bernoulli's principle has nothing to do with wings, but I was willing to modify that to say it's not a simple connection and you're better off without it for normal discussion and quick calculation. And I never intentionally insulted anyone's intelligence the way Tad continues to.) I think he's largely right, but I'll back down and modify when presented with new evidence.
Right now I'm still digesting the idea that the tug doesn't want to be yanked in strange directions by more force than a standard weak link will allow. The link on the tug end may be there to protect tug equipment from breaking during a bridle wrap, the one on the glider end may be there to prevent the tug from nosing into the ground. The poor tug has to watch everything in a 4 inch mirror, for pete's sake.
It's good to discuss and make sure we know exactly why things are there, but I'd really like to see a little less god complex from a certain someone.
Brian Vant-Hull
Re: Weak link question
What I don't get is why even bother using Tad's weak links? They don't break, they yank the tug around, why not omit them and hook to the tow line directly? If you don't get off tow in time you're an idiot anyway, and the tug's weak link is going to safe the tug and, hopefully, your glider. What's the point?
#1 Rogue Pilot
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davidtheamazing1
- Posts: 306
- Joined: Wed Jan 26, 2005 1:26 am
- Location: DC Area - Hang 3!!
- Contact:
Re: Weak link question
Maybe the point of weak links is for people that aren't as smart as Tad and would be trying to "save" the tow when they should be releasing. Also if it gets bad enough that you'd end up breaking the tug's connection you're probably be better off breaking the glider link so you don't have to deal with the tow cable.RedBaron wrote:What I don't get is why even bother using Tad's weak links? They don't break, they yank the tug around, why not omit them and hook to the tow line directly? If you don't get off tow in time you're an idiot anyway, and the tug's weak link is going to safe the tug and, hopefully, your glider. What's the point?
If we all learned when to release, and when not to, maybe we could do away with weak links altogether.
OFF TOPIC: was there a definitive answer to Kirk's question?
Re: Weak link question
If we all learned when to release, and when not to, maybe we could do away with weak links altogether.
Oh if only life were so simple.
How's it go?... that's right... Sh1t Happens.
That's what weaklinks are all about. There for that "OH SH1T" moment.
You can ponder all you like the way this or that should happen and what you should do in such a moment. But the plain fact is that when it all goes to custard, things tend to happen really fast.
Now I'm of the variety that likes to stack the deck in my favor. I like to have things that might help me out when it's all going to hell. I most certainly do not want things that don't help involved. I don't need to rely on these things to appreciate that they're there.
BTW, all this talk about "the only reason for a weaklink is to protect the glider" stuff is absolute piss. Sorry, that's a reason for weaklink. This notion that it's the only reason is nothing short of dangerous.
A weaklink's purpose is to improve your safety.
Plane and simple. The rest is how it does it.
Not having the glider fold up does help your odds of survival. So does inconveniencing you by letting go of the rope for you... whether you like it or not.
I'm sure Tad will happily write a 20 page dissertation on everything I've said here. Have fun. I don't read posts from him. If anyone else cares to discuss any of this, I'm happy to do so. You might have to pm me to get my attention as the weather here is often far more conducive to flying.
Fly safe guys.
Jim
Re: Weak link question
hey Jim;
If the weak link is to protect the pilot from certain aerobatic manuevers, then it should scale with pilot mass, plain and simple. But that's not the only consideration.
A fixed strength (if logically justified) must have something to do with the tug. I think the glider end link should scale with pilot mass up to the point where the tug doesn't want to deal with being jerked around so much. Another upper limit is the weak link on the tug. If above a certain strength it begins breaking things on the tug, then the glider weak link must be weaker than this.
So two upper limits, one for the Tug, one for the glider. Scale the link strength with tow mass up to the glider link maximum, though where that is can be debated. I don't believe like Tad that the FAA necessarily is the last word, and his 1.4 G links may be too strong, especially for heavier pilots who will just have to deal with more weak link breaks. But I think strengthening them somewhat for heavier pilots makes perfect sense.
What, did Kirk have a question?
If the weak link is to protect the pilot from certain aerobatic manuevers, then it should scale with pilot mass, plain and simple. But that's not the only consideration.
A fixed strength (if logically justified) must have something to do with the tug. I think the glider end link should scale with pilot mass up to the point where the tug doesn't want to deal with being jerked around so much. Another upper limit is the weak link on the tug. If above a certain strength it begins breaking things on the tug, then the glider weak link must be weaker than this.
So two upper limits, one for the Tug, one for the glider. Scale the link strength with tow mass up to the glider link maximum, though where that is can be debated. I don't believe like Tad that the FAA necessarily is the last word, and his 1.4 G links may be too strong, especially for heavier pilots who will just have to deal with more weak link breaks. But I think strengthening them somewhat for heavier pilots makes perfect sense.
What, did Kirk have a question?
Brian Vant-Hull
Re: Weak link question
BTW, all this talk about "the only reason for a weaklink is to protect the glider" stuff is absolute piss.
Hahahahahahahahahaha.A weaklink's purpose is to improve your safety.
#1 Rogue Pilot
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Brian,
>
You keep saying there's been 40,000 incident free tows at Ridgely, then turn around and say the present weak link system will kill people. Obviously you don't value consistency or you wouldn't be trying to change things.
<
There have been 40 K launches at at Ridgely in which - to my knowledge - no one has suffered an injury worse than a skinned knee.
There have no freakin' way been 40 K incident free tows.
An incident free tow is one in which you get on the cart and release after getting where you wanna go.
If you continue on your merry way after Zach waves his left arm that's an incident free tow. Ditto if at 1100 feet you notice that he's corkscrewing as tightly as possible, your vario's pegged, and you say "GOOD ENOUGH".
Nothing else qualifies as an incident free tow.
Examples of incidents - engine failure, tug runs out of gas, at any altitude glider is forced to release because because it gets kicked too hard to recover, at any altitude glider is forced to release because because pilot kicks it too hard to recover, glider fails to preflight harness and dolly is carried aloft at the end of a pod lanyard, any release - primary, secondary, or tug - fails at any time - (whether or not it the tug is stalled as a consequence), a weak link break at ANY point for ANY reason - legitimate or not.
An incident is also an accident if the glider gets a skinned knee or folds a seventy-five dollar downtube in half.
The launch injury rate at Ridgely is negligible enough that we can call it zero for the time being.
The launch accident rate ain't so good - based on my tiny sample of first hand observations.
The launch/tow incident rate totally SUCKS.
Now gimme a moment to rewind the tape...
Normally the one size fits all weak link results in no more damage than keeping prices high, degrading everybody's flying experience, and denying folk access to the soaring window.
However, once in a 40 K launch cycle a no fault situation arises in which the glider pilot's life is totally dependent upon the tow line. THAT'S why anybody who starts dipping significantly below 1.4 is asking for trouble, the FAA does not permit sailplanes to fly below 0.8, and people like Janni need to be protected from themselves.
>
But there's perhaps an upper limit for situations not well described by theory, and I get annoyed when someone professes to know the entire truth and everyone else must be idiots.
<
As long as you keep thinking of the weak link as an alternate release in place to protect the pilot you're NEVER gonna get this.
As I've said many times before... It took me two years to accept what James Freeman:
http://www.dynamicflight.com.au/WeakLinks.html
and a few others amongst the best minds were saying. The logic is unassailable and the data backs it up. When it finally sinks in you get this electrifying E=MCsquared sensation. I hope it will come to you sometime - it's totally awesome. Nerd Nirvana.
>
Right now I'm still digesting the idea that the tug doesn't want to be yanked in strange directions by more force than a standard weak link will allow. The link on the tug end may be there to protect tug equipment from breaking during a bridle wrap, the one on the glider end may be there to prevent the tug from nosing into the ground.
<
We need to kill this crap right now.
Think about it.
Karen - as is: two point, one size fits all.
The weak link limits her (or - for that matter - me, so configured) to 243 pounds of tow line tension.
Assuming nobody squeezes a lever the most damage that Karen can do is to use that 243 pounds to pull perpendicular to the longitudinal axis of the Dragonfly - straight up, straight down, straight left, straight right, or straight any hour on the clock you wanna name.
Let's suit me up in my my flying gear. That puts me DAMN close to 243.
I start off in the transporter bay of the Enterprise. Zach is up at a thousand feet for a morning conditions check with nothing in tow.
I say, "Scottie, beam me down to the coordinates of Zach's tail wheel, leave me there for five seconds, then beam me back (without fail)."
What the fuck do you think is gonna happen to that tug with me dangling from the extreme aft end?
THAT'S what Karen can do to the Dragonfly. 'Cept she can do it in any direction she wants. The weak link will allow her - given the time - to dwarf to insignificance the effect that Paul had on Russell.
NEITHER THE FRONT OR BACK WEAK LINK CAN ENSURE THAT EITHER AIRCRAFT REMAINS IN CONTROL.
Ralph's 2000/08/26 RELEASE FAILURE incident should have convinced you of that FACT over eight years ago. Paul just jerked the tail around - Ralph STALLED AND DROPPED the tug.
>
Donnell Hewett
Department of Physics
Texas A&M University-Kingsville
MSC 175 Kingsville TX 78363-8202
2005/02/08 18:30
It is impossible to design a weaklink to release the pilot when he loses flight control because there is no correlation between towline tension and flight control.
<
>
jimrooney
Weak link question
Something to bear in mind... the tug's weaklink is three strand.
In the tandem setup, the "weaklink" in the system is at the tug end, not the glider.
<
So - if this is indeed the case - the tandem's weak link is irrelevant - as is Paul's. So how can towing Paul with a 1.4 G weak link have any more bearing on how violently the tug's tail can be jerked around than towing the tandem?
>
jimrooney
No one is actually scared to fly with a standard weaklink. They may say they are, but deep down inside, they're not.
<
I have never launched with a release actuator farther away than four inches inboard of the port end of the basetube. At that range I was scared towing.
After experiencing a real exciting lockout seven and a half years ago I decided the range was - indeed - WAY too far and shortly thereafter engineered what today remains the best means of firing a two point release anywhere.
After that the only three things I was scared of were a bridle wrap, the problem of actuating a secondary / one point release, and a weak link break. Steve figured how to neutralize the middle one, I engineered out the other two.
The weak link problem was the last to fall - two seasons ago.
Jim Rooney does not speak for Danny and me. And anybody who believes there is such a thing as a "standard" weak link is clueless (against my better judgment I restrained myself from using the term "idiot"). And anybody who isn't scared of using a weak link anywhere south of about 1.2 is living in blissful ignorance.
I was ALWAYS scared of the "STANDARD" weak link. I was always scared it was gonna fuck up my day - and it often did (and if you count other people's "standard" weak links - it almost always did) and because it could - and often did - commit me to a forced landing.
My regular landings are the scariest part of my flying day - I don't need to do more of them.
>
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.
<
This little snippet is pretty good evidence that Jim's foe blocker doesn't work very reliably.
This is an apparent reference to the letter of Donnell Hewett's which I cross posted here.
In the post immediately following this one I will cross post my response to him so everyone can see read MY position on the issue. Scroll on down to "Releasing low over unsuitable terrain...".
>
brianvh
I don't believe like Tad that the FAA necessarily is the last word, and his 1.4 G links may be too strong, especially for heavier pilots who will just have to deal with more weak link breaks.
<
>
brianvh
Weak link question
2008/11/11 21:55:59
Well....
if it just happens to break when you are partially in a low to the ground wingover, it kinda sucks. As Tad says, the tug's pulling you away from the ground, so in many cases you're better off staying with it until you choose your moment to release. They tend to break when stuff is already bad, not before it gets bad.
<
If heavier pilots will just have to deal with more weak link breaks then they are not being allowed to fly with the safety margin afforded to lighter pilots.
THIS IS NOT HOW YOU RUN AN AIRLINE!
If there is any good evidence that the Dragonfly cannot safely withstand the 450 to 500 pound tow line tension which would keep all the big solos happy and ensure that the tug leaves with the rope - I have yet to see or hear of it.
>
RedBaron
What I don't get is why even bother using Tad's weak links? They don't break, they yank the tug around, why not omit them and hook to the tow line directly? If you don't get off tow in time you're an idiot anyway, and the tug's weak link is going to safe the tug and, hopefully, your glider. What's the point?
<
The point of having a weak link is that - even if everything else gets fucked up beyond all recognition - you'll be left with two intact planes with which people can fly away PROVIDED they have enough altitude with which to recover. NOTHING MORE - NOTHING LESS.
>
davidtheamazing1
If we all learned when to release, and when not to, maybe we could do away with weak links altogether.
<
David,
Prior to your attainment of an AT signoff you must not be put into a situation in which release timing is critical.
Upon attainment of the rating... YOU ARE -REQUIRED- TO KNOW WHEN TO RELEASE.
>
OFF TOPIC: was there a definitive answer to Kirk's question?
<
Yeah. Fulfill the requirements of your rating, use the best release configuration available, and use a weak link in the middle of the safety range - 1.4 Gs - and don't try to get it to do jobs of which it is not capable.
>
You keep saying there's been 40,000 incident free tows at Ridgely, then turn around and say the present weak link system will kill people. Obviously you don't value consistency or you wouldn't be trying to change things.
<
There have been 40 K launches at at Ridgely in which - to my knowledge - no one has suffered an injury worse than a skinned knee.
There have no freakin' way been 40 K incident free tows.
An incident free tow is one in which you get on the cart and release after getting where you wanna go.
If you continue on your merry way after Zach waves his left arm that's an incident free tow. Ditto if at 1100 feet you notice that he's corkscrewing as tightly as possible, your vario's pegged, and you say "GOOD ENOUGH".
Nothing else qualifies as an incident free tow.
Examples of incidents - engine failure, tug runs out of gas, at any altitude glider is forced to release because because it gets kicked too hard to recover, at any altitude glider is forced to release because because pilot kicks it too hard to recover, glider fails to preflight harness and dolly is carried aloft at the end of a pod lanyard, any release - primary, secondary, or tug - fails at any time - (whether or not it the tug is stalled as a consequence), a weak link break at ANY point for ANY reason - legitimate or not.
An incident is also an accident if the glider gets a skinned knee or folds a seventy-five dollar downtube in half.
The launch injury rate at Ridgely is negligible enough that we can call it zero for the time being.
The launch accident rate ain't so good - based on my tiny sample of first hand observations.
The launch/tow incident rate totally SUCKS.
Now gimme a moment to rewind the tape...
Normally the one size fits all weak link results in no more damage than keeping prices high, degrading everybody's flying experience, and denying folk access to the soaring window.
However, once in a 40 K launch cycle a no fault situation arises in which the glider pilot's life is totally dependent upon the tow line. THAT'S why anybody who starts dipping significantly below 1.4 is asking for trouble, the FAA does not permit sailplanes to fly below 0.8, and people like Janni need to be protected from themselves.
>
But there's perhaps an upper limit for situations not well described by theory, and I get annoyed when someone professes to know the entire truth and everyone else must be idiots.
<
As long as you keep thinking of the weak link as an alternate release in place to protect the pilot you're NEVER gonna get this.
As I've said many times before... It took me two years to accept what James Freeman:
http://www.dynamicflight.com.au/WeakLinks.html
and a few others amongst the best minds were saying. The logic is unassailable and the data backs it up. When it finally sinks in you get this electrifying E=MCsquared sensation. I hope it will come to you sometime - it's totally awesome. Nerd Nirvana.
>
Right now I'm still digesting the idea that the tug doesn't want to be yanked in strange directions by more force than a standard weak link will allow. The link on the tug end may be there to protect tug equipment from breaking during a bridle wrap, the one on the glider end may be there to prevent the tug from nosing into the ground.
<
We need to kill this crap right now.
Think about it.
Karen - as is: two point, one size fits all.
The weak link limits her (or - for that matter - me, so configured) to 243 pounds of tow line tension.
Assuming nobody squeezes a lever the most damage that Karen can do is to use that 243 pounds to pull perpendicular to the longitudinal axis of the Dragonfly - straight up, straight down, straight left, straight right, or straight any hour on the clock you wanna name.
Let's suit me up in my my flying gear. That puts me DAMN close to 243.
I start off in the transporter bay of the Enterprise. Zach is up at a thousand feet for a morning conditions check with nothing in tow.
I say, "Scottie, beam me down to the coordinates of Zach's tail wheel, leave me there for five seconds, then beam me back (without fail)."
What the fuck do you think is gonna happen to that tug with me dangling from the extreme aft end?
THAT'S what Karen can do to the Dragonfly. 'Cept she can do it in any direction she wants. The weak link will allow her - given the time - to dwarf to insignificance the effect that Paul had on Russell.
NEITHER THE FRONT OR BACK WEAK LINK CAN ENSURE THAT EITHER AIRCRAFT REMAINS IN CONTROL.
Ralph's 2000/08/26 RELEASE FAILURE incident should have convinced you of that FACT over eight years ago. Paul just jerked the tail around - Ralph STALLED AND DROPPED the tug.
>
Donnell Hewett
Department of Physics
Texas A&M University-Kingsville
MSC 175 Kingsville TX 78363-8202
2005/02/08 18:30
It is impossible to design a weaklink to release the pilot when he loses flight control because there is no correlation between towline tension and flight control.
<
>
jimrooney
Weak link question
Something to bear in mind... the tug's weaklink is three strand.
In the tandem setup, the "weaklink" in the system is at the tug end, not the glider.
<
So - if this is indeed the case - the tandem's weak link is irrelevant - as is Paul's. So how can towing Paul with a 1.4 G weak link have any more bearing on how violently the tug's tail can be jerked around than towing the tandem?
>
jimrooney
No one is actually scared to fly with a standard weaklink. They may say they are, but deep down inside, they're not.
<
I have never launched with a release actuator farther away than four inches inboard of the port end of the basetube. At that range I was scared towing.
After experiencing a real exciting lockout seven and a half years ago I decided the range was - indeed - WAY too far and shortly thereafter engineered what today remains the best means of firing a two point release anywhere.
After that the only three things I was scared of were a bridle wrap, the problem of actuating a secondary / one point release, and a weak link break. Steve figured how to neutralize the middle one, I engineered out the other two.
The weak link problem was the last to fall - two seasons ago.
Jim Rooney does not speak for Danny and me. And anybody who believes there is such a thing as a "standard" weak link is clueless (against my better judgment I restrained myself from using the term "idiot"). And anybody who isn't scared of using a weak link anywhere south of about 1.2 is living in blissful ignorance.
I was ALWAYS scared of the "STANDARD" weak link. I was always scared it was gonna fuck up my day - and it often did (and if you count other people's "standard" weak links - it almost always did) and because it could - and often did - commit me to a forced landing.
My regular landings are the scariest part of my flying day - I don't need to do more of them.
>
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.
<
This little snippet is pretty good evidence that Jim's foe blocker doesn't work very reliably.
This is an apparent reference to the letter of Donnell Hewett's which I cross posted here.
In the post immediately following this one I will cross post my response to him so everyone can see read MY position on the issue. Scroll on down to "Releasing low over unsuitable terrain...".
>
brianvh
I don't believe like Tad that the FAA necessarily is the last word, and his 1.4 G links may be too strong, especially for heavier pilots who will just have to deal with more weak link breaks.
<
>
brianvh
Weak link question
2008/11/11 21:55:59
Well....
if it just happens to break when you are partially in a low to the ground wingover, it kinda sucks. As Tad says, the tug's pulling you away from the ground, so in many cases you're better off staying with it until you choose your moment to release. They tend to break when stuff is already bad, not before it gets bad.
<
If heavier pilots will just have to deal with more weak link breaks then they are not being allowed to fly with the safety margin afforded to lighter pilots.
THIS IS NOT HOW YOU RUN AN AIRLINE!
If there is any good evidence that the Dragonfly cannot safely withstand the 450 to 500 pound tow line tension which would keep all the big solos happy and ensure that the tug leaves with the rope - I have yet to see or hear of it.
>
RedBaron
What I don't get is why even bother using Tad's weak links? They don't break, they yank the tug around, why not omit them and hook to the tow line directly? If you don't get off tow in time you're an idiot anyway, and the tug's weak link is going to safe the tug and, hopefully, your glider. What's the point?
<
The point of having a weak link is that - even if everything else gets fucked up beyond all recognition - you'll be left with two intact planes with which people can fly away PROVIDED they have enough altitude with which to recover. NOTHING MORE - NOTHING LESS.
>
davidtheamazing1
If we all learned when to release, and when not to, maybe we could do away with weak links altogether.
<
David,
Prior to your attainment of an AT signoff you must not be put into a situation in which release timing is critical.
Upon attainment of the rating... YOU ARE -REQUIRED- TO KNOW WHEN TO RELEASE.
>
OFF TOPIC: was there a definitive answer to Kirk's question?
<
Yeah. Fulfill the requirements of your rating, use the best release configuration available, and use a weak link in the middle of the safety range - 1.4 Gs - and don't try to get it to do jobs of which it is not capable.
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
Tad Eareckson
skysailingtowing
2008/11/06 11:41
#6745
Donnell,
While I still maintain a couple of minor points of disagreement - CLOSE ENOUGH! Can I get a framed, autographed copy of that post on acid free paper?
>
I believe everyone recognizes that "one size weak link simply does not fit all".
<
I wish.
Over the course of the past couple of seasons I've been able to batter my local crowd down enough to get a few 1.4 jobs in the air but at the flight line if a 320 pound skygod glider asks for a weak link he gets the same loop of 130 pound Greenspot as a 200 pound first time soloer.
If the big guy puts the link on the end of his two point bridle he's got about 0.76 MAX and practically something that is very likely to break at 0.4.
If the new chick puts it on her two point, she's got a solid 1.22. After she gets better and starts towing off of her shoulders she gets 1.4.
>
http://ozreport.com/12.81
Weaklinks - the HGFA rules
(Hang Gliding Federation of Australia)
Here is the requirement from the 2007 Worlds local rules (which I wrote) for weaklinks:
Weaklinks
Pilots must use weaklinks provided by the meet organizers and in a manner approved by the meet organizers. All weaklinks will be checked and use of inappropriate weaklinks will require the pilot to go to the end of the launch line to change the weaklink.
Weaklinks will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line
http://www.cortlandline.com/catalog/braid.html
and should be placed at one end of a shoulder bridle.
<
Yeah, why consider glider weight at all. Next...
We need to codify a lower limit to give people a tool with which to protect themselves from kind of crap - which, by the way, is very much alive and well in the US too.
>
Personally, I am not convinced that all hang glider pilots are qualified to recover safely from such extreme aerobatic attitudes.
<
They may or may not be but - again - even a 0.8 (or less) G weak link may be of no use whatsoever in preventing an aerobatics champ from doing a steep wingover into terra firma. He can easily find himself in a situation in which his release is his only option.
>
That is why I still recommend a 1-gee maximum weak link when towing horizontally with a good tension controlled system.
<
Fine. Peter seems to think that 0.8 presents no problem. I yield the floor to the winch crowd. From what I understand of tension controlled towing I would imagine that you'd REALLY want to be off tow if the tension climbed that much.
>
In fact, I am sure you can imagine more than one situation where getting off line is the worst possible alternative you can take.
<
YEAH...
>
Danny Brotto
2008/11/04 12:49:44
An instance where the weak link could have broken and I'm glad it didn't...
I had the Axis on the cart with the AOA a bit high, launching to the west, with a moderate 90 degree cross from the left. I came out of the cart rolled and yawed to the right with the upwind wing flying and the downwind wing stalled. It was rather dramatic. If I had released or if the weak link had broken, the downwind wing would have further stalled and I would have cartwheeled into terra firma in an unpleasant fashion. I held on tight gaining airspeed until the downwind wing began flying, got in behind the tug, and continued the flight.
Sunny later told be he was about to give me the rope and I thanked him to no end that he didn't. Lesson learned, check AOA on the cart especially in crosswinds.
-
An instance where the weak link held and it would have been nice if it had yielded...
On another instance, I was towing behind a trike being piloted by Bill Bennett as part of a demo at Fairfield (my sailplane port.) These were the early "experimental" days of aerotow. We were using a center-of-mass tow system, a three-ring circus release, and a fairly short rope. Bill commenced the tow, I came off the cart, and Bill started a rapid climb. This put me below the trike, stalled, and soon into the prop wash and tug wing-vortices. My Axis began to roll to the right, I tried to release but the polypro towline had some slack and the release mechanism held tightly. The line then tightened. I do not remember what kind of weak link was being used but with the mounting pressure I thought for sure it would break; but it didn't. I was rolling past 90 and gave the release one last yank. It released, I completed a wing over just over the tree line, and came in for a nice landing. Bill and I debriefed about the pull-up. The subsequent tow, without the rapid climb out, went okay.
Lessons learned, abandon the three-ring circus and use a decent release (I purchased the then "new-fangled" Wallaby Release) and you can't count on the weak link to get you out of an emergency situation.
<
>
Releasing low over unsuitable terrain is an obvious example of this exception.
<
I think most Dragonflies tow out of airports or more than adequate flight parks and they climb so well that terrain is not an issue 'cause if you pop off early you have - almost by definition - either enough remaining runway ahead of you or enough altitude to turn around and land normally.
In theory the worst thing that could happen to you would be to come down into propwash but I haven't heard of any good examples of this being a serious issue. I got some more info on the Texas Open case I referenced earlier and it seems that this bending occurred as a result of a pilot who was in no way qualified to aerotow getting on the cart.
But the first incident related by Danny - and another very similar recent one at Ridgely triggered by a dust devil - is the reason why I feel no one can safely aerotow below 0.8 Gs.
Danny doesn't weigh anything. If he did he'd have been flying the same loop of Greenspot and thus at a lower G rating and the probability of that thing popping at precisely the wrong moment would have gone WAY up.
The nice thing about dolly launching behind tugs is that you can release without moving your hand, in the case of two point - significantly or, one - at all.
I've developed an excellent AT release system in which I have total confidence. The pictures are up at:
http://www.flickr.com/photos/aerotowrelease/
and I'm helping a friend refine his really nice slap-on concept. I hope to have photos of it up in a few days.
The better your release system the less you think about the weak link as something that's gonna keep you out of trouble.
I can't thank you enough for the time and thought you put into these posts and for your comments regarding my efforts. I think they'll be most valuable in helping to get us to clean up our act. Definitely worth waiting for.
Tad
skysailingtowing
2008/11/06 11:41
#6745
Donnell,
While I still maintain a couple of minor points of disagreement - CLOSE ENOUGH! Can I get a framed, autographed copy of that post on acid free paper?
>
I believe everyone recognizes that "one size weak link simply does not fit all".
<
I wish.
Over the course of the past couple of seasons I've been able to batter my local crowd down enough to get a few 1.4 jobs in the air but at the flight line if a 320 pound skygod glider asks for a weak link he gets the same loop of 130 pound Greenspot as a 200 pound first time soloer.
If the big guy puts the link on the end of his two point bridle he's got about 0.76 MAX and practically something that is very likely to break at 0.4.
If the new chick puts it on her two point, she's got a solid 1.22. After she gets better and starts towing off of her shoulders she gets 1.4.
>
http://ozreport.com/12.81
Weaklinks - the HGFA rules
(Hang Gliding Federation of Australia)
Here is the requirement from the 2007 Worlds local rules (which I wrote) for weaklinks:
Weaklinks
Pilots must use weaklinks provided by the meet organizers and in a manner approved by the meet organizers. All weaklinks will be checked and use of inappropriate weaklinks will require the pilot to go to the end of the launch line to change the weaklink.
Weaklinks will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line
http://www.cortlandline.com/catalog/braid.html
and should be placed at one end of a shoulder bridle.
<
Yeah, why consider glider weight at all. Next...
We need to codify a lower limit to give people a tool with which to protect themselves from kind of crap - which, by the way, is very much alive and well in the US too.
>
Personally, I am not convinced that all hang glider pilots are qualified to recover safely from such extreme aerobatic attitudes.
<
They may or may not be but - again - even a 0.8 (or less) G weak link may be of no use whatsoever in preventing an aerobatics champ from doing a steep wingover into terra firma. He can easily find himself in a situation in which his release is his only option.
>
That is why I still recommend a 1-gee maximum weak link when towing horizontally with a good tension controlled system.
<
Fine. Peter seems to think that 0.8 presents no problem. I yield the floor to the winch crowd. From what I understand of tension controlled towing I would imagine that you'd REALLY want to be off tow if the tension climbed that much.
>
In fact, I am sure you can imagine more than one situation where getting off line is the worst possible alternative you can take.
<
YEAH...
>
Danny Brotto
2008/11/04 12:49:44
An instance where the weak link could have broken and I'm glad it didn't...
I had the Axis on the cart with the AOA a bit high, launching to the west, with a moderate 90 degree cross from the left. I came out of the cart rolled and yawed to the right with the upwind wing flying and the downwind wing stalled. It was rather dramatic. If I had released or if the weak link had broken, the downwind wing would have further stalled and I would have cartwheeled into terra firma in an unpleasant fashion. I held on tight gaining airspeed until the downwind wing began flying, got in behind the tug, and continued the flight.
Sunny later told be he was about to give me the rope and I thanked him to no end that he didn't. Lesson learned, check AOA on the cart especially in crosswinds.
-
An instance where the weak link held and it would have been nice if it had yielded...
On another instance, I was towing behind a trike being piloted by Bill Bennett as part of a demo at Fairfield (my sailplane port.) These were the early "experimental" days of aerotow. We were using a center-of-mass tow system, a three-ring circus release, and a fairly short rope. Bill commenced the tow, I came off the cart, and Bill started a rapid climb. This put me below the trike, stalled, and soon into the prop wash and tug wing-vortices. My Axis began to roll to the right, I tried to release but the polypro towline had some slack and the release mechanism held tightly. The line then tightened. I do not remember what kind of weak link was being used but with the mounting pressure I thought for sure it would break; but it didn't. I was rolling past 90 and gave the release one last yank. It released, I completed a wing over just over the tree line, and came in for a nice landing. Bill and I debriefed about the pull-up. The subsequent tow, without the rapid climb out, went okay.
Lessons learned, abandon the three-ring circus and use a decent release (I purchased the then "new-fangled" Wallaby Release) and you can't count on the weak link to get you out of an emergency situation.
<
>
Releasing low over unsuitable terrain is an obvious example of this exception.
<
I think most Dragonflies tow out of airports or more than adequate flight parks and they climb so well that terrain is not an issue 'cause if you pop off early you have - almost by definition - either enough remaining runway ahead of you or enough altitude to turn around and land normally.
In theory the worst thing that could happen to you would be to come down into propwash but I haven't heard of any good examples of this being a serious issue. I got some more info on the Texas Open case I referenced earlier and it seems that this bending occurred as a result of a pilot who was in no way qualified to aerotow getting on the cart.
But the first incident related by Danny - and another very similar recent one at Ridgely triggered by a dust devil - is the reason why I feel no one can safely aerotow below 0.8 Gs.
Danny doesn't weigh anything. If he did he'd have been flying the same loop of Greenspot and thus at a lower G rating and the probability of that thing popping at precisely the wrong moment would have gone WAY up.
The nice thing about dolly launching behind tugs is that you can release without moving your hand, in the case of two point - significantly or, one - at all.
I've developed an excellent AT release system in which I have total confidence. The pictures are up at:
http://www.flickr.com/photos/aerotowrelease/
and I'm helping a friend refine his really nice slap-on concept. I hope to have photos of it up in a few days.
The better your release system the less you think about the weak link as something that's gonna keep you out of trouble.
I can't thank you enough for the time and thought you put into these posts and for your comments regarding my efforts. I think they'll be most valuable in helping to get us to clean up our act. Definitely worth waiting for.
Tad
Re: Weak link question
Brian... yep... the issue of the tug's link is a big one and you've summed it up nicely.
The tug uses 3 strand and so all this talk about using a stronger one is academic.
You don't get to have one that's equal or stronger.
Here's the other thing missing from this conversation, and it's not a quick soundbite one.
There is more to the bar than simply strength.
See we've got a system that has an extremely solid track record. It's a high bar and you can't improve one aspect at the expense of an other. (you don't get to lower my safety margins for any reason)
The first one we've finally covered is the tug's link. Here's some others...
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.
I know when you hook up what you've got. It's assumed that you know what it is, so what? I want to know. Why? Cuz I'm on the other end of the damn rope! You don't get to make decisions about MY safety. You don't get to make decisions about how far I'm taking you into harms way. It's just not your call.
With greenspun, I know what you've got. We don't have to have a conversation about if I'm willing to tow you or not. If you roll up with something else, that conversation happens. I might decide that I'm willing to tow you, but that conversation happens. You are not the only one involved here.
So if you want to use something that "scales with weight", you need to find a common and quality controlled manufactured material that displays what it is.
Why?
You're asking a tow pilot to pull you.
You're asking someone else to join you in a dangerous environment.
You don't get to make decisions for me.
The tug uses 3 strand and so all this talk about using a stronger one is academic.
You don't get to have one that's equal or stronger.
Here's the other thing missing from this conversation, and it's not a quick soundbite one.
There is more to the bar than simply strength.
See we've got a system that has an extremely solid track record. It's a high bar and you can't improve one aspect at the expense of an other. (you don't get to lower my safety margins for any reason)
The first one we've finally covered is the tug's link. Here's some others...
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.
I know when you hook up what you've got. It's assumed that you know what it is, so what? I want to know. Why? Cuz I'm on the other end of the damn rope! You don't get to make decisions about MY safety. You don't get to make decisions about how far I'm taking you into harms way. It's just not your call.
With greenspun, I know what you've got. We don't have to have a conversation about if I'm willing to tow you or not. If you roll up with something else, that conversation happens. I might decide that I'm willing to tow you, but that conversation happens. You are not the only one involved here.
So if you want to use something that "scales with weight", you need to find a common and quality controlled manufactured material that displays what it is.
Why?
You're asking a tow pilot to pull you.
You're asking someone else to join you in a dangerous environment.
You don't get to make decisions for me.