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Re: Peter (Link Knife) Birren

Postby Birren » Sun Nov 20, 2011 7:34 pm

Free wrote:That's not what I was talking about, Peter. Your memory is worse than mine because I distinctly remember you 'bitching out' Warren S. on the more than likely defunct 'anti-power footlaunch' yahoo group that you were involved in. I can't recall if you were a moderator or not but the effect of the bitch out did seem to do the trick.
Who wants to belong to a group that acts like that?

Anything ringing a bell?
Your bell was rung in a towing accident some time ago, right? Sorry to hear about that.
Maybe that is why you can't remember?


Nope, I never bitched out WarrenS. In fact, I just went through all my emails using only "Warren" as a search term. Your name came up in one of 'em while WS came up in several dozen. He was quite helpful to me and The Coalition is preparing for the motor vote as well as when I was getting my feet wet in the marketing committee. In several of the emails where I was either the author or the recipient, in all of the copies attached to those emails, WS was NEVER bitched out or otherwise disrespected as (1) he provided quite a handy service to us all, (2) his presentations were always top-notch and (3) that I know about, everyone liked him and his contributions. "Never was heard a discouraging word."

Actually, in that accident, it was more like the clapper was tweaked... broke my larynx and a couple of ribs hitting the front bar of the dolly.

- Peter
- Peter
http://www.birrendesign.com/linknife.html - Linknife Tow Release
http://www.youtube.com/watch?v=Yx1_R8nYDrU - Static Tow Launch and crappy landing
http://www.birrendesign.com/astro.html - Objects in the Heavens - deep-sky fieldbook
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Re: Peter (Link Knife) Birren

Postby Birren » Sun Nov 20, 2011 8:11 pm

WHAT PROBLEMS OF ONE POINT USING A KOCH TWO STAGE OR TWO POINT (ONE TO ONE) IS A TWO TO ONE BRIDLE SOLVING?


Tad, in answer to this question, considering foot-launch towing only:
Problems of a Koch style over/under release bridle:
1. I've been told by several pilots (idiots all, no doubt) that unless you're really on top of your game, a chest-mounted bridle can make you feel like you're tipping over and can (and has) accelerated tripping on launch. Towing single-point from the waist gives the pilot a better feel but behaves differently v/v the control bar while still close to the ground.
2. If the towline, weaklink or bridle are not compromised and thus less than perfect, a hard snap presented by the release of the upper line can cause a premature release from tow.
3. If the Koch bar is not stowed away properly after release, or in the event of a low-level premature release, and the pilot pounds in, the bar can cause rib breakage and severe pain in the potential face plant.
4. If the AOA of the wing isn't held strongly and properly, the potential for an immediate stall at launch is increased.
5. In a severe yaw away from the tow line direction early in the tow, it's possible to wrap/snag the upper line on the front wires. Possibility is low but it's there.

Solutions with a Hewett 2:1:
1. The pull from the waist is easier to manage than a pull from the chest.
2. There is no sudden/immediate change in tension to the pilot or glider because the release is activated only once at the end of tow.
3. The 2:1 bridle "generally" doesn't hang much below the pilot's feet so the potential of snagging it on landing is low. Of course, properly stowing the bridle after release is a much better option.
4. There is some upward pull on the control bar from the lower bridle lines but maintaining a proper AOA does not require a heavy hand and it results in earlier tightening of the hang strap(s).
5. In a severe yaw away from the tow line direction at any time during the tow, the release (at the apex of the bridle) is well in front of the flying wires so no snag is possible.

Additional benefits of a 2:1:
1. The pull that's on both pilot and glider keeps everything working in unison; the pull on the glider's Cm somewhat helps align the glider at the initial point of launch.
2. Near the top of tow, the upper line's pressure on the control bar somewhat helps keep the glider from stalling, though that pressure can be overcome by the pilot.
3. At the top of tow, the upper bridle sings when in contact with the helmet (inconsequential, but I like the sound).

Negatives of a 2:1:
1. It takes a few seconds to roll up and stow.
2. If overly long and not stowed, it presents a snagging/tripping hazard on landing.

In another post, you quoted my line about success with the Linknife but commented on weaklink material. Are you confused?

And in another, you said (yet again) that I banned you from the towing list. I never did so. In fact, you're still a member. I did, however, stop engaging with you in your circular argument in support of your Rube Goldberg release mechanism.

Lastly, are you familiar with the Man in the Middle concept? It goes that when someone claims that everyone else is the idiot, that everyone else is a jerk, that it's never your fault, etc., it's usually the person doing the complaining and finger-pointing who is really at fault, either the true jerk or truly an idiot through mistaken logic and an anti-social personality. It's not paranoia when "they" are actually pointing guns at your head, except in this case, you're the shooter.

- Peter
- Peter
http://www.birrendesign.com/linknife.html - Linknife Tow Release
http://www.youtube.com/watch?v=Yx1_R8nYDrU - Static Tow Launch and crappy landing
http://www.birrendesign.com/astro.html - Objects in the Heavens - deep-sky fieldbook
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Re: Peter (Link Knife) Birren

Postby Bill Cummings » Sun Nov 20, 2011 9:15 pm

Birren wrote:
WHAT PROBLEMS OF ONE POINT USING A KOCH TWO STAGE OR TWO POINT (ONE TO ONE) IS A TWO TO ONE BRIDLE SOLVING?


Tad, in answer to this question, considering foot-launch towing only:
Problems of a Koch style over/under release bridle:
1. I've been told by several pilots (idiots all, no doubt) that unless you're really on top of your game, a chest-mounted bridle can make you feel like you're tipping over and can (and has) accelerated tripping on launch. Towing single-point from the waist gives the pilot a better feel but behaves differently v/v the control bar while still close to the ground.
2. If the towline, weaklink or bridle are not compromised and thus less than perfect, a hard snap presented by the release of the upper line can cause a premature release from tow.
3. If the Koch bar is not stowed away properly after release, or in the event of a low-level premature release, and the pilot pounds in, the bar can cause rib breakage and severe pain in the potential face plant.
4. If the AOA of the wing isn't held strongly and properly, the potential for an immediate stall at launch is increased.
5. In a severe yaw away from the tow line direction early in the tow, it's possible to wrap/snag the upper line on the front wires. Possibility is low but it's there.

Solutions with a Hewett 2:1:
1. The pull from the waist is easier to manage than a pull from the chest.
2. There is no sudden/immediate change in tension to the pilot or glider because the release is activated only once at the end of tow.
3. The 2:1 bridle "generally" doesn't hang much below the pilot's feet so the potential of snagging it on landing is low. Of course, properly stowing the bridle after release is a much better option.
4. There is some upward pull on the control bar from the lower bridle lines but maintaining a proper AOA does not require a heavy hand and it results in earlier tightening of the hang strap(s).
5. In a severe yaw away from the tow line direction at any time during the tow, the release (at the apex of the bridle) is well in front of the flying wires so no snag is possible.

Additional benefits of a 2:1:
1. The pull that's on both pilot and glider keeps everything working in unison; the pull on the glider's Cm somewhat helps align the glider at the initial point of launch.
2. Near the top of tow, the upper line's pressure on the control bar somewhat helps keep the glider from stalling, though that pressure can be overcome by the pilot.
3. At the top of tow, the upper bridle sings when in contact with the helmet (inconsequential, but I like the sound).

Negatives of a 2:1:
1. It takes a few seconds to roll up and stow.
2. If overly long and not stowed, it presents a snagging/tripping hazard on landing.


:clap: :clap: :clap: :clap: :clap: :clap: for all the above.
from here down looks personal and I'm really not up to speed on the rest.
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Re: Peter (Link Knife) Birren

Postby TadEareckson » Wed Nov 23, 2011 7:10 pm

Actually, in that accident, it was more like the clapper was tweaked... broke my larynx and a couple of ribs hitting the front bar of the dolly.

I think lots of us could benefit from knowing what went wrong on that one to get those results.

I've been told by several pilots (idiots all, no doubt) that unless you're really on top of your game, a chest-mounted bridle can make you feel like you're tipping over and can (and has) accelerated tripping on launch.

1. So you haven't actually ever given it a shot yourself. Big surprise. That was always Donnell's problem. He assumed he had everything right, made all kinds of predictions of disasters for other bridle configurations, ignored the fact that they weren't happening, and never did anything remotely resembling experimentation or reevaluation.

2. And of course nobody ever has any problems whatsoever getting off the ground unscathed with a Hewett Bridle.

3. Just how on top of your game do you need to be to run a glider into the air while being pulled by your shoulders without power whacking? I've done this myself and don't recall that it was terribly demanding.

4. Gee, the accelerated tripping on launch injury rate in Europe must be horrendous. You'd think they'd have gotten a clue and shifted over by now.

5. If you're in an environment in which you can use a dolly you're insane not to. If you're starting prone you're already tipped over, you can't get any more tipped over, and the only acceleration you feel is being converted directly to airspeed.

6. You've told me that (at least some of) the environments in which you fly are not appropriate for dolly launching. OK.

Towing single-point from the waist gives the pilot a better feel but behaves differently v/v the control bar while still close to the ground.

Zack C - 2011/04/15

After over a hundred each of hill/mountain launches, aerotows, and surface tows, I feel that platform launching is the safest way to get a hang glider into the air.

1. "Close to the ground" has nothing to do with anything. Tow angle is the issue. During a platform launched flight the tow angle is fairly constant from nearly the instant of launch all the way up and the pilot stays in a good position with respect to the control flame.

2. There are zillions of pilots who fly aero - in which the tow angle is, hopefully, zero the whole time - who tow from their shoulders only, from launch (virtually always off a dolly) all the way up. They all seem to feel just fine - unless they get into a situation in which they need all the speed they can get. In that case they're too far through the control frame and can end up screwed - but those are fairly rare events.

3. In a surface tow in which the tow angle changes - starts from zero and continuously increases (static tow for example) - yes, "close to the ground" coincides with "low tow angle". And the advantages of two point towing start disappearing pretty fast - and soon become disadvantages.

If the towline, weaklink or bridle are not compromised and thus less than perfect, a hard snap presented by the release of the upper line can cause a premature release from tow.

I'm guessing that you didn't intend to include the word "not" in that sentence and will proceed on that assumption.

1. So then you might be in at least partial agreement with:

Manned Kiting
The Basic Handbook of Tow Launched Hang Gliding
Daniel F. Poynter
1974

"The greatest dangers are a rope break or a premature release." - Richard Johnson

and have a problem with 130 pound Greenspot aerotow morons who put people up on stuff that frequently blows every fourth tow?

2. I'm an EXTREME not believer in going up with less than perfect tow system equipment.

3. There's no good excuse for blowing a towline, bridle, or weak link - two stage snap or not.

4. Can you maybe see a REAL SERIOUS problem with going up with a device which blows you off tow when you hit a certain high PITCH attitude? Something that LIMITS your PITCH attitude at the expense of leaving with an astronomical ANGLE OF ATTACK?

If the Koch bar is not stowed away properly after release, or in the event of a low-level premature release, and the pilot pounds in, the bar can cause rib breakage and severe pain in the potential face plant.

1. I've never heard of a Koch release getting stowed - properly or im.

2. Right. The bar CAN cause rib breakage and severe pain in the potential face plant. I hear that all the time. What I DON'T hear all the time is that it actually DOES. So can you cite any data on ACTUAL broken ribs and/or pain?

Jim Rooney - 2010/03/26

What do they call them again? "Chest Crushers"?

3. I had a pretty good friend who ACTUALLY had his chest crushed - and was dead a short time later. He was using a three-string. If he had been using a "Chest Crusher" he almost certainly wouldn't have had his chest crushed 'cause the Koch is probably the quickest and easiest release to actuate on the planet in the gotta-take-a-hand-off category.

4. Low level premature releases can and do kill people. There's no excuse for having a premature release.

Keith Skiles - 2011/06/02

I witnessed the one at Lookout. It was pretty ugly. Low angle of attack, too much speed and flew off the cart like a rocket until the weak link broke, she stalled and it turned back towards the ground.

5. The greatest cause of premature releases - at all levels - and the accompanying pound-ins, severe pain, and face plants - is 130 pound Greenspot. If any single item in our towing systems is a Chest Crusher, that would be the one.

If the AOA of the wing isn't held strongly and properly, the potential for an immediate stall at launch is increased.

1. Is there some kind of launch for some kind of aircraft about which that can NOT be said?

2. Given identical anchor points on the keel someone flying a one to one bridle is gonna be in better shape than someone flying a two to one bridle 'cause a greater fraction (half versus a third) of the towline tension is going to hold the glider down.

In a severe yaw away from the tow line direction early in the tow, it's possible to wrap/snag the upper line on the front wires. Possibility is low but it's there.

1. Is it there enough to document a single incident?

2. What would cause a severe yaw away from the towline direction early in the tow?

3. I've dolly launched two point behind a Dragonfly in a pretty scary crosswind (probably about as much as the operation at Ridgely would tolerate), been severely yawed away from the towline direction, and not found this to be a problem.

4. If you're flying a Koch or any other kind of one point then the bridle is nowhere near any wires.

5. If you're flying two point it makes no difference whether you're one to one or two to one - the same yaw will result in the same proximity to a wire.

The pull from the waist is easier to manage than a pull from the chest.

1. If you say so, OK.

2. So wouldn't that make the pull from a one to one bridle easier to manage than the pull from a two to one bridle since there's a sixth less in the way of towline tension going to the waist?

There is no sudden/immediate change in tension to the pilot or glider because the release is activated only once at the end of tow.

BFD. So what? Are Kochers experiencing problems with this?

The 2:1 bridle "generally" doesn't hang much below the pilot's feet so the potential of snagging it on landing is low. Of course, properly stowing the bridle after release is a much better option.

1. Why is this being listed in the "solutions" category. The Koch release "generally" hangs even less below the pilot's feet and has an even lower potential for snagging on landing.

2. I'm not really worried about this anyway 'cause I find that problems with bridles snagging or being tripped on during landing are entirely imaginary.

There is some upward pull on the control bar from the lower bridle lines but maintaining a proper AOA does not require a heavy hand and it results in earlier tightening of the hang strap(s).

1. Seems a little dubious to put a bridle pulling up on the basetube in the "solutions" category.

2. I wouldn't benefit from the earlier tightening of the suspension 'cause I can launch with tight suspension any time I feel like it.

3. So you're saying that having tight suspension during a foot launch is preferable to loose. Care to engage in the "US Hawks Hook-In Verification Poll" thread?

4. This claimed advantage is only relevant to foot launching. ALL dolly launches and platform launches begin with fully loaded suspension.

5. A one to one bridle will pull up less than a two to one bridle.

6. Are Kochers suffering from the disadvantage of not having their basetubes pulled up and having their suspension tightened earlier?

7. How much earlier does a two to one tighten the suspension of someone who launches with a loose strap than the aerodynamic lift does for a loose strap Kocher?

In a severe yaw away from the tow line direction at any time during the tow, the release (at the apex of the bridle) is well in front of the flying wires so no snag is possible.

1. That's a function of the release placement. It has absolutely nothing to do with the two to one, one to one, Koch issues.

2. In one point / Koch everything's WAY the hell in front of and below the wires.

3. You can release a two to one or a one to one either from the top or the bridle apex.

4. If you release from the top you can configure to blow with both hands on the basetube.

5. If you release from the bridle apex you better be good at fighting lockouts with one hand.

6. I can name a lot of people who'd still be alive if they could've released with both hands on the basetube.

7. I'm still waiting to hear a single account of somebody who wasn't deliberately yawing away from the towline snagging a nose wire.

8. I get real tired of people in this sport creating actual deadly problems in the course solving totally imaginary ones.

Additional benefits of a 2:1...

We're definitely gonna need some 'cause I'm singularly unimpressed with what we have so far.

The pull that's on both pilot and glider keeps everything working in unison; the pull on the glider's Cm somewhat helps align the glider at the initial point of launch.

1. We're not pulling on the glider's center of mass. We're pulling at or in front of its HANG POINT.

2. ALL of the tow force - Koch, two to one, one to one - goes to the hang point. All, two thirds, half by way of the pilot respectively - but that's where it all winds up.

3. Anchoring the top at the hang point does NOTHING to help align the glider. As you move the trim point forward on the keel you probably get a little yaw stability - but I'm thinking that it's probably dwarfed by what you get from sweep.

4. I don't notice people towing one point having any more problems aligning the glider at the initial point of launch than anyone else.

Near the top of tow, the upper line's pressure on the control bar somewhat helps keep the glider from stalling, though that pressure can be overcome by the pilot.

1. Are Kochers and platform launchers having problems stalling near the tops of tows?

2. Near the tops of tows - who cares?

Negatives of a 2:1...

You seem to have left out a couple of minor issues like...

There is some upward pull on the control bar from the lower bridle lines...

...compromised situations when people really can't afford "some" upward pull on the control bar from the lower bridle lines and...

A straight base tube is better than a speed bar for static towing. The bridle has less of a chance of locking in on one side of a speed bar. (Just a suggestion)

Timothy P. Churchill - 1985/02

A novice pilot named Andre, suffered a broken leg, dislocated hip, fractured pelvis, and, worst of all, severe head injuries when his Phoenix 6-C apparently locked out at approximately 75 feet. Andre's bones have since healed without the need of surgery but the damage to his brain will probably be with him for the rest of his life. His condition was described by the doctors as comatose with a 25 percent chance of total recovery.

...when somebody leaves the field as a vegetable 'cause those bridle lines exerting some upward pull on the control bar have snagged on something on the control bar.

In another post, you quoted my line about success with the Linknife but commented on weaklink material. Are you confused?

Until I know what post and what you're talking about - definitely.

And in another, you said (yet again) that I banned you from the towing list. I never did so.

So I'm wondering what you meant by:

Peter Birren - 2009/05/17

For the most part, his fuel line's been cut.

and why I lost my ability to post IMMEDIATELY afterwards.

I did, however, stop engaging with you in your circular argument in support of your Rube Goldberg release mechanism.

1. I don't have a Rube Goldberg release MECHANISM - I have a Rube Goldberg release SYSTEM.

Zack C - 2011/01/10

When I first saw your release years ago on the Oz Report forum my impression was the same as most people's. I didn't know what the pictures were showing but it looked way more complicated than it needed to be. After seeing the problems that even the best releases on the market have and learning more about your release, however, I understand why you made it the way you did and the advantages it provides.

I have a Rube Goldberg release SYSTEM...

Scott C. Wise - 2009/04/13 09:56

What some are missing with the K.I.S.S. comments is that the USE of the release must also fit within the Keep It Simple, Stupid principle. But it can be a real trick to make both the mechanism and trigger simple AND easy to use (while not removing your hand from the base tube).

Peter Birren - 2008/10/27

Imagine if you will, just coming off the cart and center punching a thermal which takes you instantly straight up while the tug is still on the ground. Know what happens? VERY high towline forces and an over-the-top lockout. You'll have both hands on the basetube pulling it well past your knees but the glider doesn't come down and still the weaklink doesn't break (.8G). So you pull whatever release you have but the one hand still on the basetube isn't enough to hold the nose down and you pop up and over into an unplanned semi-loop. Been there, done that... at maybe 200 feet agl.

...so I don't hafta have an idiot Rube Goldberg response and lucky Rube Goldberg recovery when the s*** hits the fan.

2. Can you quote anything from my circular argument in support of my Rube Goldberg release mechanism?

3. The conversation when you didn't cut my fuel line had ABSOLUTELY NOTHING to do with ANYBODY'S Rube Goldberg release mechanism. It was entirely and only about revisions to USHGA's useless bull s*** aerotowing SOPs and guidelines - about which one of our members here (see immediately above) recently said:

Bill Cummings - 2011/10/26

Very fine effort Tad.

And this isn't the first time I've told you that.

Tad Eareckson - 2009/05/10

There ain't s*** in my proposed SOPs, AT Guidelines, nor letter to the FAA about my, your, nor anybody else's release system so let's drop that fabrication along with my string of serial killings in southern California.

Just curious... What did YOU find so objectionable in them?

...it's usually the person doing the complaining and finger-pointing...

But not always, Peter.

Zack C - 2010/12/13

I had a very different mindset too back then and trusted the people that made my equipment. Since then I've realized (largely due to this discussion) that while I can certainly consider the advice of others, I can't trust anyone in this sport but myself (and maybe the people at Wills Wing).

And for anybody who wants to take the time to and has the capability of understanding the physics and history of this aspect of the sport I can make that case airtight and hands down.

...an anti-social personality.

Ya DEFINITELY got that part right.

George Bernard Shaw

Man and Superman - 1903
Maxims For Revolutionists

The reasonable man adapts himself to the world: the unreasonable one persists to adapt the world to himself. Therefore all progress depends on the unreasonable man.

And you've always been extremely reasonable with everybody. Always more than welcome in USHGA and on any forum. Never been banned from anything.

Peter Birren - 2009/05/17

You're pissing off too many long-time members with your evangelical and contentious pursuit of pilot regulation.

Bart Weghorst - 2011/02/25

I've had it once where the pin had bent inside the barrel from excessive tow force. My weaklink was still intact. The tug pilot's weaklink broke so I had the rope. I had to use two hands to get the pin out of the barrel.

No stress because I was high.

1. Perish the thought that "pilots" should hafta adhere to any rules or standards whatsoever - like the EXISTING ones that say the release has gotta be able to handle twice weak link and the tug's weak link is supposed to be a hundred pounds heavier than the bridles.

2. Perish the thought that Arlan Birkett be deprived of the right to kill himself along with his student by violating several regulations and standard procedures and face no consequences - aside from getting killed.

3. I don't like your cohesive, inbred, brain damaged little cult. I don't like it 'cause it's made sure we've stayed stuck in 1981 and killed a lot of people who didn't need to be. There's little WORSE in aviation than social personalities.

It's not paranoia when "they" are actually pointing guns at your head, except in this case, you're the shooter.

You've had more success killing people with your support of Donnell's Skyting Criteria and promotion of a Pitch and Lockout Limiter than I ever will with any of my figurative guns.

But... Back to the main issue.

I was REALLY hoping you'd say something about...

3. C-M DISTRIBUTION

The towing force must be distributed between the components of the flying system proportionally to the masses of the respective components.

4. C-M ATTACHMENTS

The towline and/or bridle must be attached as closely as possible to the effective center-of-mass of each of the components and must not be allowed to touch any other part of the flying system.

...the thinking behind the reason for the development of the two to one bridle in the first place.

What's this supposed to do for us? What's so freakin' important about these items that they make it onto a list of a dozen elements required for safe towing and things like releases that can be actuated with both hands on the basetube, weak links that don't blow up in your face every other tow, and rolling launches are nowhere to be found?
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Re: Peter (Link Knife) Birren

Postby Bob Kuczewski » Wed Nov 23, 2011 7:56 pm

Tad,

I don't know if you've got a point with your tirade or not. But what I do know is that you're not at all interested in engaging anyone in productive discussions. Instead, you just want to get in every jab that you can whether it's got any basis in fact or not.

I used to think that maybe you had insights that the rest of us had somehow missed. That was before the long FTHI discussion when you proved to me that you either didn't know or had forgotten what it was like to launch in windy, gusty, and dangerous foot-launch conditions. That FTHI discussion revealed to me that you're really just here to stake out some position and then prove yourself right ... whether you actually are or not.

So Peter,

If you've got an unlimited amount of time to respond to every long and insulting post that Tad writes, then you're welcome to dissect/answer his questions one by one. I suspect if you do this, then Tad will do the same to your posts. Therefore the size and effort to reply to each corresponding post will roughly double with each "volley" until one of you (most likely you, Peter) will realize that this is a massive waste of time and just walk away.

So in order to save all the wasted time between now and then (and hopefully keep you from walking away from the US Hawks), I suggest that you answer what you want (or nothing at all) and ignore the rest of Tad's posts as many of us are learning to do.

Also, for your information, Sam has banned Tad from the SWTHG forum (within the US Hawks Chapters area), so if you're annoyed with Tad's badgering that's a safe place to have a sane discussion without being constantly interrupted.

Finally, I apologize for Tad's aggressive approach. We're still struggling with the free-speech / sane-speech tradeoff, and I can see we still have more work to do. I hope you'll bear with us while we come up with a reasonable policy to allow unpopular views to be voiced without allowing them to drown out everything else on the forum.

Thanks,
Bob Kuczewski
Founder - US Hawks Hang Gliding Association
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Every human at every point in history has an opportunity to choose courage over cowardice. Look around and you will find that opportunity in your own time.
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Re: Peter (Link Knife) Birren

Postby TadEareckson » Thu Nov 24, 2011 5:29 am

Peter Birren - 2011/11/22

Hi, all.

Just stumbled on this discussion after stumbling across Tad again on USHawks. (It's been a trip - pun intended.) Anyway, thanks for all your kind compliments on the Linknife. And truth be told, I find the barrel release to be an excellent device. Only one thing bothered me in what Tad wrote: that it takes 20 pounds of pull to activate at higher tensions. I hadn't heard this before but it sound logical as the tow force is applied TO the release (as opposed to THROUGH it like the Linknife which needs only 4 pounds of pull).

What Tad ACTUALLY said was:

The release in my avatar, by the way, is under a direct load of 400 pounds (i.e. 800 pounds towline tension) and can be actuated with a pull of just under 20 pounds.

1. That's 800 pounds towline, Peter. That's two and a half Gs for my rather heavy solo glider. That's half a G over what's legal.

2. At max legal I'm under 16 pounds.

3. The max allowable pull given as a standard in "The excellent book, Towing Aloft, by Dennis Pagen and Bill Bryden" and endorsed by the USHGA Towing Committee is 25 - so I'm in pretty good shape no matter how ya wanna slice it.

4. At one and a half Gs I'm under 12.

5. Maxing out a Straub/Rooney Link ("We had six weaklink breaks in a row at Zapata this year.") I'm at about 6.

6. At normal Dragonfly tow tension I'm at 3.

7. For ANY of those - BFD.

8. I've got a choice between two releases...

Release A is engaged by inserting a pin through a loop, rotating it back, and securing it by sliding a barrel an inch forward. It will require a max twelve pound pull in a situation I will encounter at an average frequency of never in a thousand lifetimes - literally, and then only after I've done some really major pooch screwing.

Release B will NEVER require more than a four pound pull no matter what the tension but to engage it I've gotta cut a piece of string, tie the ends together to form a loop, open a quick link, install the loop on the quick link, screw the quick link secure, thread the loop through a slot in the length of a barrel, and engage the loop with the tow ring on the end of the towline.

Release A is bulletproof.

Release B can be put out of commission with a few stems of wheat stubble.

Guess which release I'm gonna use.

Clearing up details on a tale of woe: In various places, this thread included, Tad has mentioned the aerotow launch accident in which I broke my larynx and 4 ribs. It was my 2nd ever aerotow, from a home-made dolly (by another club), and behind a trike (though that's of little consequence). In hindsight, it's my opinion that the cradle was too deep, much deeper than is in common use today. When the glider lifted off and I picked up said dolly, I released but it was too soon and too low. When the dolly lifted off the ground, the wheels castered, so when I released it, the dolly stopped which pulled back on my base tube. The glider, of course, nosed over as the tow force was transferred to the upper part of the V-bridle. I swung through the frame, hitting my throat and lower ribs on the front cross-member of the dolly (parachute saved my upper ribs). The .8G weaklink broke immediately (much to Tad's consternation should he ever read this) and the glider and I ended upside down. My voice was a bit soft for a few days and the ribs healed up nicely.

It wasn't the dolly's fault. It wasn't the fault of the guy who built it. It wasn't the club's fault, nor the tug pilot's. It was my fault for not fully understanding the nature of the beast and for being headstrong in forging ahead into an area in which I wasn't completely familiar.

So that's my story and I'm sticking to it :-)

Thanks again for all your notes about the Linknife.

1. So the primary cause of the crash was that you didn't know what you were doing.

2. And a contributing issue was a design problem with a critical component of the tow system.

3. But if you had just allowed a lot of airspeed to build up with the dolly on the ground and had eased the glider out of the brackets you'd have been fine - like, presumably, everybody else using that cart was.

4. All the damage that you sustained occurred before the weak link blew.

5. And, of course, NO POSSIBLE WAY would a 1.5 G weak link have blown when the glider slammed in, right?

6. And as long as everybody uses a 0.8 G weak link no one who blows a dolly launch will ever be hurt any worse than you were.

7. And there's never been a recorded incident of anybody getting seriously int*rcoursed up by a 0.8 G blowing when a glider is standing on its tail 'cause Donnell says we can ignore any such data.

8. And, of course, since breaking four ribs and a larynx is a perfectly satisfactory outcome we should all just use 0.8 G weak links and forget about taking advantage of existing dead man switch technology which blows you off tow if your hand comes off the basetube or you relax your bite on the string between your teeth.

...

1. Pile-ins off of carts DO NOT EVER HAPPEN to competent pilots using good equipment at competent operations. They happen ONLY as a result of glider pilot incompetence, uncertifiable dollies, and/or flying at Florida Ridge.

2. So Peter wants us ALL to fly with weak links at 0.8 Gs - the ABSOLUTE BOTTOM EDGE of what's legal for sailplanes and forty percent of the top of what's legal for hang gliders - to mitigate the aftermath of a nonexistent problem because he IMAGINES that a pooch screwer who uses a 1.5 G weak link will most assuredly be dragged to his death (assuming, of course, that he's not already dead as a consequence of the pile-in.

We don't have problems with people piling in off of the cart, Peter. And when we do I typically don't care what happens next. Same way I have zero interest in discussing what steps a person who skips hook-in checks should take WHEN he launches unhooked.

Where we have REAL problems is with people otherwise flying reasonably or perfectly competently...

http://www.youtube.com/watch?v=bTa6XL16i0U

...crashing because they were stupid enough to go up with 0.8 G weak links.
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Re: Peter (Link Knife) Birren

Postby Bob Kuczewski » Thu Nov 24, 2011 10:35 am

Tad,

Peter posted a very candid explanation of what happened to him. He thanked people for the kind compliments on the Linknife and added that the barrel release is also an excellent device.

Your response should have been something like: "Thanks for the kind compliments on the barrel release. The Linknife has been an excellent innovation in towing, and I appreciate that its inventor would offer kind compliments on any of my own work."

But instead, you go on and on trying to prove that your barrel release is superior to the Linknife and to belittle Peter for his candid explanation of his mistake - on the 2nd aerotow of his life!!

Tad, can you see the hostility in your response? I'm asking very seriously if you can even see the hostility in your own post. Because if you can't even see it, then there's no hope of correcting it.

Thanks in advance.
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Re: Peter (Link Knife) Birren

Postby TadEareckson » Thu Nov 24, 2011 8:09 pm

I don't know if you've got a point with your tirade or not.

1. Of course you don't. It's not a subject in which you have any interest.

But what I do know is that you're not at all interested in engaging anyone in productive discussions.

Well sure you do. And if you say something it MUST be true 'cause you're the one with ultimate control of this forum. And screw Zack and Antoine if what they know is different from what you know.

Instead, you just want to get in every jab that you can whether it's got any basis in fact or not.

Weird. I didn't think you had much interest in whether or not things are factual.

I used to think that maybe you had insights that the rest of us had somehow missed. That was before the long FTHI discussion when you proved to me that you either didn't know or had forgotten what it was like to launch in windy, gusty, and dangerous foot-launch conditions. That FTHI discussion revealed to me that you're really just here to stake out some position and then prove yourself right ... whether you actually are or not.

1. That's what it revealed to YOU. That's NOT what it revealed to others.

Bill Cummings - 2011/11/21

NO DISAGREEMENT HERE.

2. Let's say that your lunatic position that we should ease up on hook-in checks just prior to launch so that we can better cater to idiots hell bent on killing themselves by getting on ramps with no crew in gales which give them one percent safety margins is valid and that I'm totally full of s*** on THIS issue. So that means I couldn't POSSIBLY have insights that the rest of you had somehow missed. Right?

3. And, by the same "logic", because Peter's totally out to lunch on two to one bridles, weak links, and Pitch and Lockout Limiters, his Linknife is a useless dangerous piece of junk that no one should allow within twenty feet of his glider. Right?

If you've got an unlimited amount of time to respond to every long and insulting post that Tad writes, then you're welcome to dissect/answer his questions one by one.

Does Peter really need you to tell him that?

I suspect if you do this, then Tad will do the same to your posts.

Yeah. And perish the thought that we should have an in depth discussion geared toward understanding and getting people on the same page with respect to fundamental aeronautical theory in an organization geared for people with the attention spans of puppies when we can just have votes to determine the most popular perceptions of reality.

Therefore the size and effort to reply to each corresponding post will roughly double with each "volley" until one of you (most likely you, Peter) will realize that this is a massive waste of time and just walk away.

He doesn't really need you to tell him that either. He's every bit as good as you are at walking out of discussions as soon as he finds his positions deteriorating and is unable to answer questions without crashing and burning.

So in order to save all the wasted time between now and then (and hopefully keep you from walking away from the US Hawks), I suggest that you answer what you want (or nothing at all) and ignore the rest of Tad's posts as many of us are learning to do.

1. Yeah, that's the way all advancement in science is made - by ignoring any inconvenient aspects of reality that you don't like and/or are over your depth and sticking your head in the sand.

2. Peter didn't come over here to help you build an even crappier version of USHGA - Peter came over here to call me an ignorant slut. Leave him alone - we're both perfectly happy working on that level.

Also, for your information, Sam has banned Tad from the SWTHG forum (within the US Hawks Chapters area), so if you're annoyed with Tad's badgering that's a safe place to have a sane discussion without being constantly interrupted.

What will keep the US Hawks from becoming another USHPA or HGAA?

You will ... hopefully. The price of freedom is eternal vigilance. Everyone has to do their part once in a while. If you see something that's not being done correctly, then it's your duty to speak out. One big difference between the US Hawks and other organizations is that the US Hawks really does honor the free speech of its members.

1. Yeah, right.

2. Yeah Peter. You and Sam should get along famously. And get Jims Rooney and Gaar in on the cult.

Finally, I apologize for Tad's aggressive approach.

Pace yourself, Bob. Don't let yourself get all apologized out at this stage of the game.

We're still struggling with the free-speech / sane-speech tradeoff...

And by sane speech, of course, Bob means the popular stuff with which he and most everybody agrees. When Bob established US Hawks on a free speech foundation he never intended it to include unpopular speech from unpopular people.

...and I can see we still have more work to do. I hope you'll bear with us while we come up with a reasonable policy to allow unpopular views to be voiced without allowing them to drown out everything else on the forum.

1. Don't worry, Bob. You've got an EXCELLENT start on the problem. Take quotes out of context, accuse your opponent of dishonesty without presenting actual evidence, pretend to speak on behalf of a consensus of other members, start limiting avenues of speech, make up retroactive rules of convenience... You've learned from the masters while they were doing the same things to you. You'll do just fine.

2. I'm REALLY curious to know how I can "DROWN OUT" everything else on the forum. I can't force anybody to read what I write, I encourage people who have no interest in what I'm saying not to read me. And I have no interest in restricting what anyone else says here and no ability to do it anyway - those are are your departments.
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Re: Peter (Linknife) Birren

Postby Birren » Fri Nov 25, 2011 8:34 am

4. All the damage that you sustained occurred before the weak link blew.

5. And, of course, NO POSSIBLE WAY would a 1.5 G weak link have blown when the glider slammed in, right?


4. Yes.

5. I don't know. But if A breaks at 225 and B breaks at 412, which would break sooner with less residual affect on the pilot? And if A worked in 100% of the time (personal experience) in normal towing situations, why should B even be considered? (A is 4-strand 130# braided dacron kite string; "greenspot" is, I think, fishing line.)

Tad, have you ever been dragged on a blown foot launch with too strong of a weaklink? I have, sideways. It ain't fun. Some years later when more had been learned and things changed, I messed up again in similar fashion, the .8G weaklink broke and kept me from being dragged as before. As well, one of our newer pilots on his first day out static towing, had a wimpy, wallowing takeoff from "running into" the line. The observer called for the car to stop, pilot slid in on his belly and the weaklink broke allowing him to stop quickly without the glider doing a ground tumble. Had the weaklink been stronger...

But I guess empiric evidence like this doesn't count for anything in your world.
- Peter
http://www.birrendesign.com/linknife.html - Linknife Tow Release
http://www.youtube.com/watch?v=Yx1_R8nYDrU - Static Tow Launch and crappy landing
http://www.birrendesign.com/astro.html - Objects in the Heavens - deep-sky fieldbook
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Re: Peter (Link Knife) Birren

Postby Bob Kuczewski » Fri Nov 25, 2011 8:37 am

Tad,

I asked you one simple question:

bobk wrote:Tad, can you see the hostility in your response? I'm asking very seriously if you can even see the hostility in your own post. Because if you can't even see it, then there's no hope of correcting it. Thanks in advance.

You didn't answer. Yet you want me (and others) to engage you in endless dialogue and answer all your questions, when you won't answer a single one of ours?

Furthermore, your shotgun posting approach turns one discussion into ten. And anyone who's foolish enough (as I have been in the past) to answer those ten will be faced with ten times ten (100) more. Sir Isaac will tell you that's exponential growth and is unsustainable. That's why I've advised Peter (and everyone else) to stop playing your game.

So how about if you answer my simple question about whether or not you can see the hostility in your post? If you'll answer that question and would like to post a single question in return, then I'll be happy to try to answer it. But if you include multiple questions (direct or implied) or embed your question in a long tirade then I'm going to ignore you and start working on implementing a more official "ignore" system for the US Hawks.

Finally, you wrote:

TadEareckson wrote:When Bob established US Hawks on a free speech foundation he never intended it to include unpopular speech from unpopular people.

That's a lie which I can easily disprove by the fact that I invited you, Tad, to join us. There can be no greater proof in the entire universe that I intended to include unpopular speech from unpopular people.    :srofl:
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