Zack,
One of the guys in our club (one of the few that actually realize taking a hand off the bar to release is a very bad thing) developed a variant on the spinnaker cable release.
What's he doing with his teeth from launch to two hundred feet that's so important that he can't use them to bite or stop biting something?
Have him check out:
http://ozreport.com/forum/viewtopic.php?t=14221
Tad's release
Paul Farina's done a pretty good job along those lines.
He's used it for dolly launch aerotowing for a while and I'm not aware of any issues with it.
For one point dolly launching there are a lot cheaper easier simpler lighter cleaner better ways.
http://www.flickr.com/photos/aerotowrelease/sets/72057594141352219/detail
I've towed in this situation using a V bridle (routed under the basetube) without issue.
Lotsa folk have towed with Wallaby, Lookout, and Bailey releases lotsa times without issue. That don't make having the bottom half of your bridle pulling up on your basetube at launch a great idea.
On multiple occasions I've seen the second stage release hit inadvertently instead of the first stage, causing the tow to terminate prematurely.
I've seen people miss really huge fields in really easy range in really easy conditions. There's no great excuse for hitting the full dump / stage two paddle instead of the stage one 'cause when you're doing it there is, by definition and as you say, no shit hitting the fan. Take your time and do it carefully.
I've also seen the weak link break after the first stage release, but I don't think this will be an issue with a sane weak link.
Right.
Larry,
The road is loose gravel with berms on either side.
Ya go with what makes the most sense after a sane process of threat assessment. I'd say that foot over dolly in this environment is a no brainer. But is there something taking platform off the table or making it less desirable?
They do break at a lower and lower values the more times we tow on one.
http://www.hanggliding.org/viewtopic.php?t=11497
Aerotow release options?
Adi Branch - 2009/07/02 12:50:02
From what I can gather the US has some quite different (dated?) ways of doing things which it appears are not used here in the UK, and some of the reasons I've heard cited for not using these methods relate directly to accidents in the US.
For instance, the idea of tying your own weak link is absolute nuts to me, as is using a bit of string for the job! Over here it's aluminium only (sailplane style link) and if I turned up with a bit of tied string, I'd be shown the exit road.
Use Tost weak links - with the reserve inserts. They're gonna maintain their ratings forever.
Tell me more about this.
Just sayin' that the more people you have configuring their systems such that the Linknife can get dragged while the glider's getting moved around and/or landing the more you're gonna see them clogged and disabled by dry grass. Yeah, you can write that off to pilot error in that they've failed to properly preflight the system but the system is introducing another element that can, has, AND WILL be screwed up.
And if you've got something that does the job just as well or better, isn't a heavy draggy piece of junk, doesn't cost an arm and a leg, and makes things more idiot resistant - you go with it. You don't do second best.
He has me convinced that not threading is "better" than threading the bridle and the logic seems solid in that respect.
Peter's an idiot. He swallowed Donnell's "Skyting Criteria" hook, line, and sinker and is concerned only with adhering to that collection of bogus assumptions regardless of where the real threats are coming from and how obviously deadly they are.
Everybody here and everybody with half a brain or better knows that it's a really bad idea to take a hand off the basetube in the course of a lockout. But here's what Donnell has to say on the issue:
Sometimes I am asked if a more conventional release mechanism would be preferred. Specifically one wonders whether it would be wiser to have a release lever right there by the pilot's hand rather than located on his abdomen. Well, yes, it is true that a conventional hand release would be quicker to release than a body release, but in a typical emergency situation, the pilot's hand release is seldom located at the right spot on the control bar to effectively initiate the release, and in a truly panic situation, it is much easier for a person to find a release on his own body than at some specific location on the control bar. Furthermore, it would seem that a single release on the body would be as easy to operate as the two separate releases on a conventional system. The body release also frees the pilot to move his hands anywhere over the control bar and to change from prone to erect flying or vice versa.
This is absolute lunacy. The safest way to tow a glider into the air is to put it on a dolly and start the pilot proned out with both hands on the basetube and his finger on the trigger of a release at the top end of a one to one two point bridle and use a weak link that won't ever blow.
And here's how, nearly thirty years later, Donnell's STILL trying to tow gliders into the air:
http://ozreport.com/forum/viewtopic.php?t=21649
Truck Towing Accident in South Texas
Gregg Ludwig - 2010/10/28 15:46:59
Here is another report from a student (H-0) that may shed some light on the methods of instruction used. This student weighs about 250 pounds and was using a glider too small for his first tow over asphalt as reported.
28th and 29th I will be up in Kingsville, at the Kleberg County Airport about 8 am. I will be training with the Doc. He will be having lessons there Saturday, depending on weather conditions. Will be towed up with a winch - this will be my first tow. Have just been doing foot launch, will get some airtime in on those days.
-
I had to stand like a post, and not move at all once the truck took off at 25 mph with one foot in front of the other, and I am still standing in the same place leaning back, with the payout feeding me line, and there is a strange feeling, odd feeling to being pulled by the payout.
Then I take the first step to the run, and I am now running 25 mph, I am thinking, oooOOOOH SHIT, hope I don't have to run that far, hoping the HG gets lift so I don't have to run no more... My F-A running down the runway like a rocket. There is no wind, I have the right angle of attack, the HG is up, but still not enough lift for the pilot.
I can't reach my CUT line 'cause I have both hands on the downtubes, and if I let go of the Coke bottle grip I will crash.
I feel like pushing the HG into the air, or jumping up so it can lift, but I do not - that would make my situation worse.
I feel I am about to fall into the asphalt face first and crash, I am at my run limit, and feel I can not take another step. Still the glider is not lifting me.
The winch operator lets go of the pressure of the payout winch, my run comes to a jog, and to a stop. I drop to my knees.
But that's OK. The "flight" is being conducted within the parameters of the Skyting Criteria so it is, obviously and by definition, SAFE.
And here's Peter's implementation:
http://groups.yahoo.com/group/skysailingtowing/message/6726
Weaklinks
Peter Birren - 2008/10/27 23:41:49
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 (.8 G). 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.
This is also a safe tow because the unplanned semi-loop happened at maybe two hundred feet instead of maybe one hundred feet and THERE WAS NO POSSIBILITY OF A BRIDLE WRAP because he uses a CLOSED BRIDLE SYSTEM.
If he had slammed back into the runway headfirst at fifty miles per hour because he hadn't recovered from his unplanned semi-loop or his 0.8 G weak link had blown while he was standing on his tail it would have STILL been a safe tow because his release activation point was readily accessible and the system included a weak link which will infallibly and automatically release the glider from tow whenever the tow line tension exceeds the limit for safe operation - WELL UNDER the universally recognized limit of 1.0 Gs.
Yeah, the logic SEEMS solid but it's absolute rot cause:
1. The cost of using a closed bridle is that you throw a lot of crap into the air and eliminate any sane and easy means of implementing a finger-on-the-trigger release.
2. You can easily construct a bridle that's close to being physically incapable of wrapping.
3. You can configure a secondary weak link so that there's a near hundred percent certainty of it blowing on the severe jolt that you experience immediately following a wrap.
4. You can put a string in your teeth so that even if your bridle wraps after you trigger the release and the secondary weak link holds you can still be on base back to the launch line while some moron like Peter is doing an unplanned semi-loop while he's fumbling around trying to find the lanyard tied to his shoulder strap.
5. Even with all the cheap junk that these criminally negligent high volume flight parks are throwing in the air people aren't being creamed because their threading bridles wrap. And they do ZILLIONS of tows.
6. When people DO get creamed at these criminally negligent high volume flight parks it's almost invariable because they did or didn't take a hand off the basetube - damned if you do, damned if you don't aviation at its demonic best.
7. Bridles are most likely to wrap following high tension releases and there's very rarely much in the way of tension involved in really deadly lockout situations - contrary to the popular perception.
...Mel (the advanced instructor working with me on getting this going here) has a Koch setup, but doesn't really like all that stuff on his chest.
NOBODY really likes it. But it sure beats the crap out of leaving the runway in a body bag the way Shane did.
I haven't tried it yet as Peter pretty much had me convinced of the merits of the solutions he has been using...
Got any exorcists you'd feel comfortable working with for a week or two?
...and I hadn't seen any accident reports from his neck of the woods. I would like to hear about them now though.
http://groups.yahoo.com/group/skysailingtowing/message/6726
Weaklinks
Peter Birren - 2008/10/27 23:41:49
I know about this type of accident because it happened to me, breaking four ribs and my larynx... and I was aerotowing using a dolly. The shit happened so fast there was no room for thought much less action. But I wasn't dragged because the weaklink did its job and broke immediately on impact.
That one work for ya?
And he's still too freakin' stupid to understand that:
1. The weak link has got one and only one job - and preventing dragging after a blown DOLLY launch ain't it.
2. If the weak link had HELD and he HAD been dragged he wouldn't have broken four ribs and his larynx 'cause that happened as a function of the instant stop and it was the weak link failure that permitted the instant stop.
The Hewett bridle does feel better to me (forces do seem to be more manageable when correcting on tow) than the waist only one I used back in the 90's platform launching (and that I still use when scooter towing at the park in the Condor.
What Donnell has failed to understand for all these decades is that ALL of the tow force is going to the glider at its hang point no matter what it is or isn't routed through on its way.
From the pilot's perspective two things are going on as a consequence of some portion of tension being routed through him and his suspension.
1. The more tension the heavier he's gonna feel. It's gonna take more muscle to move him X inches but those X inches are gonna result in more response from the glider. Just like putting on fat or taking on ballast.
2. If there's a major forward vector and everything's going through the pilot - à la one point aero - he's gonna pendulum forward (leave the glider behind a bit) such that when he stuffs the bar he's still a foot short of stuffing the bar. The lower the performance (glide ratio) of the glider the more pronounced this problem is gonna be.
In platform everything's going through the pilot - and he's thus very heavy - and he's trimmed properly with respect to the glider all the way up 'cause the tow angle is constant and mostly down.
The other extreme is one point aero. You're getting more climb per pound of tension 'cause it's pulling full forward / nothing down so it's more efficient and you can climb with less of it. You're heavier and you've gotta look down and back to find the basetube and you really don't wanna be in a Peter Birren rocket situation 'cause you can't stuff the bar very far to hold the nose down and ride out the thermal.
There are several ways to keep the pilot in proper trim position with respect to the control frame when you're pulling forward.
1. Donnell accidentally did this with all that two to one crap while he was trying to solve a nonexistent problem based on a bogus assumption. He put two thirds of the pull on the pilot and one third on the keel forward of the hang point. He thus reduced the pendulum force on the pilot and trimmed the glider faster.
2. At about the same time and totally independently Bill Brooks and Howard Edwards - of Mike Lake's crowd - accomplished almost the exact same thing, without all the deadly crap strung all over the place, simply by anchoring the bridle a third of the way up the suspension from the pilot to the glider. The pilot's "weight" and the trim we're almost exactly the same with the Brooks as with the Hewett Bridle.
3. A two point aerotow bridle evenly splits the tension between the pilot and glider. The pilot "weighs" not much more than he does in free flight and is better tuned into the control movements and response and you can perfectly trim the glider to the tug by moving the anchor point fore or aft on the keel. The lower the performance of the glider the farther fore the anchor point.
So yeah, the Hewett Bridle does "FEEL" pretty good 'cause it's pretty close to what you're used to in free flight. But it's totally useless in platform and totally unnecessary in aero and, looking at the entire duration of a surface tow with a constantly increasing tow angle, markedly inferior to a Koch two stage (or a Lake Bridle). And people just get used to the feels of the other configurations during a few easy training flights.
I'm trying to follow in Steve Wendt...
Bad idea. He killed 1.5 students within the space of a four month period 'cause he totally failed to adhere to USHGA rating and aerotowing requirements and pissed all over the efforts of two people - yours truly and Steve Kinsley - to hand him better technology on a silver platter. And neither one of us is happy about it. And nothing's changed in the half decade since.
...and Pat Denevan's steps in that regards...
The one that was fully killed would still be around if he had been Pat's student 'cause he's one of the few instructors who knows what a HOOK-IN CHECK is and understands the meaning of the words "JUST PRIOR TO LAUNCH". I don't know how he is on towing but if he's using a two to one bridle he needs at least a little work.
...but all that "stuff" on me and in front of me does concern me...
It's useless. Get rid of it. Work with the Koch.
Convince me on this before I try it.
See above.
And don't be afraid to TRY stuff - especially stuff that other people have been doing just fine for decades. Don't try it when it's blowing twenty, gusting thirty, and crossing sixty over asphalt - but TRY it.
I learned and taught on the dunes and we all got to be pretty solid, versatile pilots 'cause there was all kinds of crap we could try and get away with without hurting ourselves.
I keep imagining all the ways things will fail and, as we've discussed before, I'm a pessimist, but a pessimist that wants to fly in a hostile place as conveniently as I possibly can. I know there is no golden fleece that will protect me, but want to do the best I can with what I have around me here in the high desert.
TOTALLY with you on that.
My most successful safety choice has always been "Doesn't feel right. Not going to do it."
Not entirely with you on that. A LOT of people have ended up in really bad shape right after having felt just super about everything until being eight feet down the ramp and suddenly realizing why the glider was a little higher than what they're used to.
And sometimes there's no rational reason for us to be feeling uneasy about doing or trying something and we're better off for having gone ahead.
Gregg Ludwig said he would come out...
Gregg's reasonably good but he's not all there by any means and he never follows through on anything.
Dave Broyles and he are two closest ST supervisors to me...
Dave isn't a hundred percent but he's DAMN GOOD, is a major pioneer, and worthy of a lot of respect.
Wagner in Dakota and Peter seem to surface tow a good bit without hurt.
(Devin) Wagner - like Peter - has absolutely no clue what a weak link is and that makes him extremely dangerous. Ridgely has towed tens of thousands of people and I don't think anybody's been more than scratched at launch but they're extremely dangerous. You don't evaluate equipment, operations, and people by what HAS happened - you look at what CAN happen. And you can get a pretty good feel for what CAN and WILL EVENTUALLY happen by looking at what frequently happens at altitude where there are no consequences - the way Mike did when watching Todd hacking away at his bridle with a hook knife for three or four minutes several thousand feet over a dry Nevadan lake bed. Nobody's ever been hurt in hang gliding as a consequence of being pessimistic or underestimating his driver or fellow pilot.
I hope I can too.
I hope you do WAY better than Peter. I know a few people who've done worse but they're in a distinct minority.
I am attracted to your analytical processes, even though you don't surface tow a lot.
Thanks. I actually haven't surface towed or even been around it in sixteen and a half years. The good news is that nothing's changed since then. The bad news is that nothing's changed since then.
The fun thing about what I'm doing is that it's way more important to be able to read and do junior high level math and science than to have any airtime. And anyone who can do that is in a good position to make a positive contribution to this stupid, broken, ruined branch of aviation.
I don't want to be maimed or dead and don't want to maim or kill anyone else, so we're being pretty cautious in all our pursuits here.
You're never gonna make it at a big commercial tow operation - not enough of the Right Stuff.
Thanks much for participating here and keeping me busy. Keep the questions coming.
.