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?