Lemme take this one out of order - before "Releases" - 'cause it's relatively easy to deal with. The other one could take a book - this one just a magazine.
This is one area where I'm not following you completely. The tow line isn't just providing thrust...in the case of a lockout, it's the cause of the emergency. Get rid of the line and you get rid of the lockout.
Hang gliding has way too much genetic memory of towing just through the control frame rather than half, most, or all through the pilot.
By 1979/09/26 Brian Pattenden had figured it out and addressed the Norfolk (England) Hang Gliding Club. Donnell Hewett got a similar idea over here a bit later. The Norfolk crowd and Donnell started putting stuff in the air about the same time. Norfolk used stuff that worked. Donnell used stuff that was geared to deal with a lot of nonexistent problems predicted by a lot of voodoo physics and bogus assumptions and was dangerous as hell.
Both movements were treated like shit by the national hang gliding establishments. Donnell's approach - unfortunately - prevailed 'cause he put out a newsletter that went out all over the world and eventually got backed by USHGA. The Norfolk guys got totally - and, to no small extent, deliberately - screwed out of their place in history.
http://groups.yahoo.com/group/hhpa/message/11147
Len Smith - 2010/09/17 20:16:05 UTC
I believe that I may be one of the few pilots to have experienced structural failure as a direct result of a tow. There was no weak-link in the system. Here's what happened: I was boat towing in 1986 (snatch launch from a beach in Maryland) using a two point bridle connection with an auto-release on one end triggered by release of the other end.
He didn't experience structural failure as a direct result of a tow - he experienced structural failure as a well known and easily predictable consequence of using a Hewett Bridle - even this improved edition for which Henry Wise can claim credit (1983/01). And it's very doubtful that a weak link would've made any difference whatsoever.
With frame towing the "pilot" was pretty much along for the ride. His control authority was extremely limited, the guy in the BOAT (you didn't want to do a whole lot of this stuff over terra firma) was mostly calling the shots, and you didn't want to track too far away from what was pulling you without releasing 'cause the system was REAL roll unstable.
Most of the gliders were flimsy, uncertifiable junk that regularly folded in response to overpowered lead footed incompetent drivers.
But even then there was a lot of expensive, high quality tow equipment around and there were a lot of highly skilled, experienced, competent people running things pretty safely - even given the limitations of frame towing. (Dave Broyles was in the middle of all of this stuff. If you ever get a chance to spend some hang waiting time with him...)
Lockouts were a serious problem but - even with the nasty instability of the system - stalls, from the documentation on which I've been able to get my hands, appear to have been the biggest killers. And people were - appropriately - scared shitless of worn towlines and bad splices.
Then Donnell came along with "center of mass" towing and pronounced his bridle self stabilizing and the lockout a thing of the past - UNLESS the pilot allowed the glider to get so far off track that the bridle or pilot contacted the control frame or a nose wire. (Find a good lockout on youtube sometime and watch how off center the pilot and bridle get.)
And to compensate for a pilot always presumed to be incapable of piloting, Donnell mandated a 200 pound weak link which would blow before the glider got too far out of line or nose high enough to risk a stall. And whenever gliders got horribly turned or whipstalled anyway Donnell would explain it away by alleging an accidentally doubled weak link.
Towed hang gliders immediately started handling a lot better and stalling and crashing a lot more.
And of course by this time the gliders were all certified and capable of pulling half a dozen Gs. Read: when the gliders could fairly easily be pulled apart nobody was using weak links and when they couldn't EVERYBODY was - and staying well south of one G to boot. Is this a great sport or what!
So... What was the question? Oh yeah.
There's this huge cultural fear of low level lockouts left over from the dinosaur days but if you look at the records of high volume platform tow and (dolly launched) aerotow operations you start noticing that - for people who have half an idea of how to fly a glider anyway - they're pretty much nonexistent. I don't know how many tens of thousands of flights have been launched at Ridgely to date but I know of no really good examples.
You come off the back of the truck or cart with a good head of steam and you're pretty bulletproof - barring, of course, the rare dust devil with your name on it. And even then a lockout is very far from a given.
You should be able to get to a safe altitude almost as consistently as passenger jets - and passenger just off the runway don't have sane bailout options.
Also... Even with the best possible equipment, people, and reactions on both ends of the line. If we got the kinds of lockouts down low that we do up high (with a lot of vertical air movement), a lot of them simply wouldn't be survivable. And I don't see those happening.
You wanna see crashes? Watch what routinely happens after low level weak link failures. You won't hafta hang around the runway all that long - especially when the guy prioritizes getting on his feet over landing the glider (like they all do).
Get rid of the line and you get rid of the lockout.
And any hope of putting more distance between you and the only thing that can hurt you.
Rob Kells tuned me into the idea that blowing tow instantly ain't necessarily the best knee-jerk reaction to a lockout. The most important thing you need to do is get level by the time you get to the ground. You can be locking out AND climbing and a delay in release may very well give you the altitude to get things back under a reasonable level of control before the flight ends.
I certainly don't mean to suggest that all your worries are then over...
Correct. What most people fail to understand is that - for the most part - they're just beginning.
...but while I'll agree there are some situations when it's better to remain on the line, I think those are exceptions rather than the norm.
No freakin' way. Again, low level lockouts are virtually nonexistent for rolling launches and halfway competent pilots. The truth is you could use thousand pound weak links and weld releases shut for the first two hundred feet and be hard pressed to note a difference.
With the absolute shit that most people fly with we're pretty much doing the welding thing anyway. Look at the crap your HHPA poster boy is using:
http://groups.yahoo.com/group/hhpa/
No way that's gonna do him any good in a critical situation. And that's what EVERYBODY uses. If low critical situations which required timely releases were anything but freak occurrences we'd be killing tow pilots at the rate of once a week all summer long.
Hang gliding culture has just decided that it's acceptable to kill someone every time that freak occurrence DOES manifest itself.
And in case Ryan Voight is listening and still doesn't get it... Don't count on the weak link to save your ass - especially on a payout winch.
Is this implied urgency in releasing not at odds with the concept of it being safer to remain on tow?
Nope. Just for that freak occurrence that's very unlikely to ever happen to you but extremely likely to happen to someone you know.
If I was ever giving you a tow, I'd never consider cutting the line or dumping pressure.
In that freak situation that DOES require immediate dumping of tension the evidence is pretty strong that the guy up front simply can't react quickly enough to make any difference. Even a tug driver with his eye on the mirror and a finger on the trigger is no match for a glider pilot with a lever on the downtube or a barrel on the shoulder.
But most people use releases they have to reach for.
Yeah. They keep doing stupid dangerous shit 'cause they get away with it just about all the time. If - over your entire hang gliding career - you do a hang check in the setup area and launch five minutes later under the assumption that you're still hooked in the chances that you're gonna get seriously hurt as a consequence of an unhooked launch are fairly remote. On 2010/11/06 B Asher and his glider came out smelling like roses. And people started talking about hang checks, letting the nose pop up at the transition from flat to hill, and the paramount issue of banning Tad.
If they're busy fighting the glider, it may be better to 'release' for them.
Yeah, it MAY be.
2006/05/06 - Nuno Fontes - 83214 - Advanced - California - scooter tow
http://ozreport.com/forum/viewtopic.php?t=2266
Nuno Fontes - Hang Gliding Towing Accident.
Nuno Fontes - 2006/05/27
We were towing on the lee side of some thousand foot mountains. I had flown without problems an hour before.
I got to about a hundred feet and the glider was completely veered to the left due to the strong crosswinds from the right.
What made me hesitate and not release was having the right wing way up and being stalled and very low. I had the feeling I was going to be catapulted backwards if I released and had a clear notion I was going to hit dirt in a tailwind.
The best option seemed to be to resist the lock out and slowly bring the glider down, even if it was crooked, but another problem arose when the observer had the tow line cut when I was down to about fifty feet.
I had no chance. The glider that had been hanging on like a kite dead leafed to the ground. The left leading edge hit first, destroying it along with the nose plates. My body's impact point was the left shoulder and the left side of my head and neck.
I remained unconscious for about twenty minutes with a bloody face from what poured from my nose. The chopper arrived about an hour after the crash. I was already semi-conscious but in a lot of pain and having trouble breathing. I was hauled to Stanford (about half an hour flight time).
The toll: fracture and crushing of the upper humerus, several broken ribs, a lung pierced and collapsed by one of them, and broken C1 vertebra right by the artery. They considered surgery, but the no-surgery risk was lower - they feared a chip would rupture the artery.
But that is NEVER the driver's job or call.
On 1996/05/11 my old Kitty Hawk Kites instructor colleague Lawrence Battaile launched off the beach on the Sound - scooter, anchored and buoyed turn-around pulley - into a strong wind with his starboard tip stalled. He was fighting for control and rolled hard and I was 99 percent certain that he was gonna die in two seconds exactly where I was standing on the dock. I didn't stick around to watch.
By the time I got to shore I was wondering why I hadn't heard a crash and turned around astonished to see him up and getting ready to soar the tree line.
Jonny Thompson had hit the gas. "You did WHAT?!!!" Ran totally contrary to all the crap about hang glider towing with which I had ever been indoctrinated. He pulled him out of the stall - similar to but much worse than the Danny Brotto aerotow situation maybe a decade later. If he had done anything else it would have been really really really BAD.
What I was taught as a winch operator was to let off on the gas if things start to go south (but not stop) and only dump pressure if recovery still looks impossible.
As we have just seen above that can be a really bad idea. You can't automatically default to less or no tension. You gotta start thinking like a ten-year-old kid flying a kite - which is EXACTLY what Jonny did and the only reason Lawrence is still alive. Sometimes the kite starts getting out of control and the kid pays out more string and at others he runs like hell into the wind - and he doesn't use a weak link.
Since I can't trust people I'm towing will be willing or able to free themselves from the line when it's in their best interest, I'm inclined to follow what I was taught.
- Then you shouldn't tow them - just like you shouldn't throw an alleged Hang Two who doesn't know how to fly a glider with his hands on the basetube off the ramp at Packsaddle.
- If you do tow people with limitations of skill, judgment, and/or equipment everybody should be made aware that each flight is a dice roll.
- I'd rather let die ten people who can't do or aren't doing their jobs on the back end of the line than take a chance of breaking the wrist of one who can and is by second guessing him and overriding his judgment.
- Are these the same people that taught you to do a hang check and assume you are hooked in on launch, use a loop of 130 pound Greenspot as an AT weak link, and use a Bailey release for towing behind the trike?
