Towing Aloft

[Tad Eareckson]

Think I'll start a little series on one of hang gliding's many lethal little publications:

Towing Aloft
Dennis Pagen and Bill Bryden
Sport Aviation Publications
1998/01



As far as books are concerned, Towing Aloft's predecessor was:

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

Very interesting to follow hang gliding culture's stupid, warped, pathetic, decades long efforts to reinvent sailplane towing through the pages of these two publications.

Sailplanes come from the sailplane store ready to be towed from a built in release point. Release can be effected without compromise of control and a weak link on the end of the towline protects the plane from being structurally overloaded. That's about all you really need and hafta know to start having good, clean, safe fun.

Hang gliders have always come from the hang glider store adaptable for towing with - if one considers the harness as part of the aircraft - a fairly easy means of hooking it up for tow. The releases can be engineered with widely varying degrees of difficulty so that separation can be effected without compromise of control - but seldom are - and a weak links on the ends of towlines and/or bridle ends can and should protect the glider from being structurally overloaded - but often aren't configured to do the job.

Until about seven years after publication of Manned Kiting all hang gliders were being hooked up wrong. A two or three point bridle distributed the tow tension to the top and bottom of the control frame. The top connection was OK but the bottom made the glider very dangerously roll unstable and seriously limited pitch control authority.

The gliders themselves sucked. They were crude, divergent, and tended to be underbuilt. Most of the towing conducted was over water (fortunately) behind powerful water ski boats without controlled or even well moderated tension. If EVER a situation was screaming for weak links this was it.

But in the entire freaking book there is ABSOLUTELY NO MENTION OF WEAK LINKS - save for a reprint of the FAA FARs covering sailplanes.

This:

"Never take your hands off the bar." - Tom Peghiny

and this:

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

they got right. And even though the bottom hookup was really wrong the hardware was really good. EVERY SINGLE PHOTOGRAPH of contemporary state of the art equipment with requisite detail depicts a lever or two on the basetube at hand position and the releases themselves are all well engineered Schweizer sorta things.

I guess there was some real Darwin stuff going on - with the gliders and bridle configurations as deadly as they were people didn't fuck around with factors over which they DID have control and spent the bucks to do them right.

Also, the fact that they were doing the bridle wrong made it easy to do the engineering to do the release for the wrong bridle right. It's when you're pulling off of a swinging squishy pilot with lotsa flexible appendages all over the place that things get to be a pain - mounting and connecting to rigid straight tubing is a no brainer.

So then at the beginning of the Eighties damn near everything changes fast. People figure out that they need to be pulling all, two thirds, or half through the pilot (or near the pilot on his suspension) with anything left over going to or near the hang point and the Comet has made the scene and the gliders are all strong, stable, and certified.

On tow these gliders are still roll unstable but a thousand times less so and a thousand times more otherwise controllable. There's very seldom a big penalty for shitrigged inaccessible releases, the selective pressures are pretty much taken out of the equation, and the hardware DNA starts going to hell. It's the evolutionary equivalent of shooting all the Cheetahs and watching what starts happening to the Thompson's Gazelles after a few generations - 'cept a million times faster.

Throw in three quarter G weak links and a bunch of idiot tow operators and the deleterious mutation rate goes to light speed - if one weak link blows and lets some moron off the hook at just the right time hang gliding culture will ignore the other ninety-nine needless pops which result in broken downtubes and go into overdrive producing Bailey and Wallaby releases.

So now taking your hand off the bar is a non issue and a rope break or premature release is ALWAYS a GOOD thing.

A weak link is the focal point of a safe towing system.

A weak link is a very simple device--typically a loop of line--that is intended to break in the event towline tensions exceed a safe or desired threshold.

Pro Tip: Always thank the tug pilot for intentionally releasing you, even if you feel you could have ridden it out. He should be given a vote of confidence that he made a good decision in the interest of your safety.

PRECISELY ONE HUNDRED AND EIGHTY DEGREES from what hang gliding had right as published almost a quarter century earlier. Total lunacy.

Go through Towing Aloft from the front of the front cover to the back of the back cover.

As easy as it is to configure for both hands on the basetube one point aerotow and as brain dead easy as it is to do two point there are but four drawings of a glider with a Wallaby lever at or appearing to be at a usable location and ZERO photos of an AT glider safely configured.

There is a whole slew of photos of release levers on downtubes where we KNOW they became practically and totally inaccessible in oscillation and lockout situations.

There are ZERO drawings and photos of any other hang or para glider configured for both hands on the controls actuation EXCEPT a couple of daguerreotypes of Bills Moyes and Bennett towing standards.

Despite the fact that there were bite controlled throttles used for Soarmasters in the Seventies there is not a SINGLE REFERENCE to a bite controlled release actuator.

There is not a SINGLE REFERENCE in the entire stupid book to a release which allows both hands on the controls for a hang or para glider being advantageous or even desirable.

There is not a SINGLE INDICATION that the authors understand that a configuration that auto releases at high pitch attitudes - like the one that killed two US pilots in 1996 shortly before publication - is the least bit dangerous.

I witnessed a tug pilot descend low over trees. His towline hit the trees and caught. His weak link broke but the bridle whipped around the towline and held it fast. The pilot was saved by the fact that the towline broke!

Even after this neither one of these idiots reveals a ghost of an understanding that if you don't have a weak link on THE END OF THE TOWLINE - as the USHGA and FAA regulations clearly state - you NEED weak links on BOTH ends of the bridle(s).

There is not a SINGLE SERIOUS TREATMENT of a weak link as a device which protects a glider - or release - from being overloaded. EVERYTHING in the book regarding weak links is a bunch of totally clueless bullshit strategy to get them as close as possible to normal tension to make the tows as "safe" as possible. Recommended MAXIMUMS are 1.20 for hang glider surface, 1.00 for aero, and 0.75 paraglider.

One ultralight sailplane "pilot" is spoken of favorably for his use of 0.20 - no, that's not a typo, you heard me right - ZERO POINT TWO ZERO. That's a QUARTER of the MINIMUM the FAA ALLOWS for towing in REAL aviation. That's about fifteen percent of what a sailplane manufacturer specifies.

There is not a SINGLE INDICATION OF UNDERSTANDING that a weak link failure under any circumstances can be anything more serious than a minor inconvenience.

And about half a dozen years later after Dennis finds himself in a situation in which his life was seriously endangered by a bent pin release which required diversion of a hand from the task it was performing and very likely would've been terminated if the tug pilot had made a good decision in the interest of his safety, his one point system had auto released, or the focal point of his safe towing system had vaporized we still don't get a renunciation of all the crap he and Bozo Bill had written.

[Tad Eareckson]

Dennis Pagen - 1994/01

Taking Off Unhooked
A New Perspective

Forgetting to hook in before taking off has been a serious problem since the beginning of our sport. To solve this problem we popularized pre-launch hang checks. After losing a couple of friends in the early years to the failure-to-hook-in syndrome, I realized that such a mistake seems to be related to a quirk of human nature. Having a quirky nature myself, I further realized that I am not immune to such a mistake. So I resolved to avoid distraction, excess haste and excitement at launch and to always perform a hang check. For the past season I also added what Pat Denevan calls the hook-in check which consists of lifting the glider until the tug of the harness is felt and saying "hooked in" out loud.

On September 28, 1993 at 9:10 AM I performed a hang check and took off unhooked after 19 years of not even coming close. Here I will tell you how it happened, why I think it can happen to anyone, and my best guess at a cure.

PROBLEMS

I pried myself out of bed at 6:00 AM for the Morningside glide ratio contest. Along with the rest of the pilots I took seven sled rides, then the morning winds set in. A friend, Rami Hyari, and I returned to the top to practice for a spot landing contest later in the day. I positioned behind Rami, hooked in and performed my hang check. He launched and I picked up my glider to move to the edge of the hill. I noticed my right plastic tip had become dislodged and was about to fall off. I didn't want to lose it in flight so I unhooked to fix it. As is my careful policy, I held my carabiner in my hand so I wouldn't forget to hook in. At the tip I needed two hands, so I hooked the biner to my harness and attached the plastic fairing. As I walked back to my control bar I noticed Rami was still in the air, so I quickly got under the glider and carried it forward in order to see his progress. I didn't intend to take off but I was still holding the glider and watching the setup. He landed off to the side of the spot, and since training was going on at the time in the same general area I thought, "If I take off right now I have a clear shot at the spot since the students are resting."

Without hesitation I began my run with a couple of slow strides. I immediately entered the airflow which was about 10 mph and the glider lifted. I lowered the pitch and accelerated my run. At top speed I let the glider lift and then let go when I detected the problem. I tumbled down the hill and torqued my foot, which left me gimpy for a week. My glider went on to fly nicely and land perfectly in the middle of a pond. Had this been a cliff, I might not be here to write about it.

First, let me note that I see why such launches progress to the bitter end. I could have easily stopped myself and the glider on my first two slow steps. However, when my nose met the flow it lifted and my automatic pilot said pull it down. From that moment onward I was committing a full-blown charging run. The point is this: launching unhooked feels exactly like a situation in which the nose is gusted upwards. In most cases a pilot will react in such a situation with nose-down control, thereby preventing early detection of the problem.

But the real mistake was made before I began running. Obviously a break in my routine (fixing the tip), a distraction (watching Rami), haste (trying to launch before the students) and possibly fatigue (six hours of sleep and even seven previous flights) all contributed to my failure to hook in.

After the incident I had a vivid memory of the whole affair and tried to figure out what went wrong. I came to a startling conclusion which is the main reason for writing this piece. Despite carefully developing good pre-launch habits, I erred because distractions that cause us to forget to hook in are equally as likely to cause us to forget to perform our safety checks. Think about that. It is now my belief that hang and hook-in checks, while important, are not by themselves a foolproof cure for failure to hook in accidents. Something more is needed.

SOLUTIONS

I have explored several solutions. An obvious one is the use of electronic hook-in alert devices. In airplanes such devices as stall and low-fuel warnings have proven effective. I have no doubt that hook-in buzzers will work, but their complexity, weight and fiddle quotient lead me to believe that a large number of pilots will not use then unless required to do so. I inquired further.

A very good policy that the Australians first popularized is hooking the harness into the glider first, then crawling into the harness. This system works and is recommended for many pilots. However, there are some caveats: First, I know a couple of sites where the pilot should not be hooked in to the glider as it is wrestled to launch because of uneven launch and tricky conditions. It is not necessarily safe to climb into the harness at the launch point in these cases. This is especially true when a full wire crew isn't available. It should be noted that when you are self-launching you are more vulnerable when hooked in during the ground handling stage.

In my personal situation, I attend competitions frequently and prefer to be fully harnessed long before launch so that all I have to do is hook in and go. This avoids a quick struggle with my harness and lets me preflight the connections at leisure. It would not be safe to use one method in competition and another for recreational flying. Any break in our routine can lead to errors. So hooking the harness to the glider first does not appeal to me, but it is a good system. However, be aware that if you use this system, then for some reason put your harness on first or unhook to look at conditions, you are more likely to forget to hook in since you have initiated a different procedure.

Finally, I came to address my personal situation by reaffirming my good habits and adding a wrinkle. I maintain low anxiety at launch, set up and get ready to fly efficiently but without undue haste, try to hook in before I move my glider, perform a hang check (lying down and walking forward), and perform a hook-in check just before I begin my run.

But the difference between now and before is post-hypnotic suggestion. Hypnosis is a powerful method for enabling the subconscious mind to control our overt behavior. My method is to prevent my body from taking a step at launch unless I first perform a hook-in check, affirming that my harness is attached to my glider.

I have used hypnotism in the past effectively and am convinced this method will work. For those readers unfamiliar with hypnotism, let us note that not everyone is susceptible to the process, but for those who are, it can produce some surprising effects. If you do not have a handy hypnotist, you can still use the concept by finding a quiet, relaxing spot, sitting comfortably and imagining yourself floating in the clouds. As you pass each cloud breathe deeply and let yourself relax more. When you have reached the point of total relaxation, imagine that you are standing at takeoff with your glider in position. Tell yourself you cannot take a step without hoisting the glider and feeling the harness tug. Once you imagine this tug, proceed with your imaginary launch. Repeat this procedure about ten times in this relaxation session and experience several sessions in a one- to two-week period. With such a practice you will have added a policy of hook-in insurance.

It is my sincere hope that my experience and thoughts relating to the hookless launch phenomenon will help prevent it from befalling others. I am compelled to say that the more we feel "it won't happen to us," the more we are vulnerable to its occurrence. Furthermore, I believe that hook-in check routines and both of these practices are only 100% effective if we add the mental training that prevents their being forgotten. Finally, I wish to thank Pete Lehmann and G.W. Meadows for the HOOK-IN T-shirt. I'll attach it to my front wires.

So thirteen years after USHGA adopts a hook-in check JUST PRIOR TO LAUNCH as a requirement for every flight of every rating Dennis, after conducting gawd knows how many instructor certification clinics - including one of mine, is gonna start adding this little "wrinkle" of Pat Denevan's to his own routine.

Gee, Dennis, are you suggesting that a few of the rest of us might try doing this ourselves? I dunno, if our instructors aren't implementing this it's probably not such a great idea.

So let's jump ahead four years and three months from this little booboo to the publication of Towing Aloft...

References...
7 - hang check
1 - Aussie Method
2 - hook harness into glider before connecting to towline
3 - locked carabiner
4 - hook knife accessibility

Suggestions to signal launch readiness by nodding, kicking leg to the side, calling clear...
7

References to hook-in checks, launch assistants and/or drivers looking for hook-in checks and/or verifying connection JUST PRIOR TO LAUNCH...
ZERO

In the thirteen plus years since publication of Towing Aloft...

Unhooked tow launch numbers...
Astronomical.

Broken backs...
1

Lower legs amputated...
2

[Tad Eareckson]

http://groups.yahoo.com/group/skysailingtowing/message/4049
Towing errata

Bill Bryden - 2004/04/01 16:20:18 UTC

Some aerotow releases, including a few models from prominent schools, have had problems releasing under high tensions. You must VERIFY through tests that a release will work for the tensions that could possibly be encountered. You better figure at least three hundred pounds to be modestly confident.

Maybe eight to ten years ago I got several comments from people saying a popular aerotow release (with a bicycle type brake lever) would fail to release at higher tensions. I called and talked to the producer sharing the people's experiences and concerns. I inquired to what tension their releases were tested but he refused to say, just aggressively stated they never had any problems with their releases, they were fine, goodbye, click. Another person tested one and found it started getting really hard to actuate in the range of only eighty to a hundred pounds as I vaguely recall. I noticed they did modify their design but I don't know if they ever really did any engineering tests on it. You should test the release yourself or have someone you trust do it. There is only one aerotow release manufacturer whose product I'd have reasonable confidence in without verifying it myself, the Wallaby release is not it.

ACKNOWLEDGEMENT

A manual of this scope entails gathering information from many sources. No single individual can posses all the necessary experience covering all the facets of towing. Therefore we are greatly indebted to those developers, instructors, manufacturers and experimenters who have brought us modern towing and have shared their insights. We especially thank Gerard Thevenot for teaching us to aerotow, Wallaby Ranch for refining our skills and Raven Hang Gliding for their helpful input. We also owe a debt of gratitude to Wayne Sayer, the Wallaby Ranch, and Raven Hang Gliding for proofreading the manuscript.

Individuals such as Donnell Hewett, Dave Broyles, Lars Linde, Mike Robertson, Brad Kushner, Malcolm Jones, David Glover, Gregg McNamee, Jan Alda, Alan Chuculate and Bill Moyes have also offered specific information either through their writing or by personal communication. Finally we wish to thank individuals and operations who have generously contributed photos to our project. John Heiney, Brad Kushner, Miami Hang Gliding, Kitty Hawk Kites, Moyes Delta Gliders and Wallaby Ranch especially provided a multitude of great images. Their work has enhanced this book tremendously.

Dennis Pagen -- Bellefonte, PA

The towline release is a critically important piece of equipment. It is the device which frees you from the towline and it must be failure-proof. Numerous designs have evolved over the years--some very good and some not so good. Unfortunately, releases are items that many pilots feel they can make at home or adapt from something they have seen at the hardware store. Two fatalities have occurred in the past five years directly related to failures of very poorly constructed and maintained releases. For the sake of safety, only use releases that have been designed and extensively tested by reputable manufacturers. Listed below are various types of releases available with their attributes and applications.

Provided in Appendix III is a performance test specification for towline releases. This is not presented to give you guidelines for making your own, but rather to make you aware of the requirements of a good release in order to select and purchase good equipment (See Appendix IV).

Hardware for sailboat rigging has been used by some for releases. Spinnaker shackles and other devices have yielded mixed results; it really depends upon the specific hardware device used as the core for the release. A few designs with these have performed very well and others have not; some can be extremely difficult to open under high loads. Be wary and test them thoroughly before flying with them. These are generally only used in applications where a Schweizer style release could be used. One of the best places to use spinnaker releases is on the end of an aerotowing V bridle. Such a release is commercially available already fabricated (see Appendix IV).

AEROTOWING RELEASES

Releases in any towing operation must be fail-safe. If it is time to release for any reason, the release must always work. In Chapter 2 we covered releases in general. Here we'll look at releases specifically set up for aerotowing.

Releases are safety devices. Do not skimp on their quality.

Aerotowing Glider Releases

The type of releases used at the glider end of the bridle arrangement often depends on the bridle arrangement itself. We'll review the common ones that have proven to be safe and effective.

Oh here - let me provide a few reviews of the common ones that have proven to be safe and effective...

Gregg McNamee - 1996/12

If your system requires you to take your hand off the control bar to actuate the release it is not suitable.

Ralph Sickinger - 2000/08/26 22:18:20 UTC

After the second failed attempt to release, I thought about releasing from the secondary, but before I could move my hand the tug stalled and started to fall...

Joe Gregor - 2004/09

...the gate was found closed on the Wallaby-style tow release.

http://ozreport.com/9.009
2005 Worlds

Davis Straub - 2005/01/11

Rohan Holtkamp did an analysis of the accident, in particular the bridle and weaklink, which never broke. The weaklink was caught on the release mechanism, a standard spinnaker release found on bridle systems used at Lookout Mountain, Moyes, Wallaby Ranch, and Quest Air. The release clamp has an arm that is thicker at the release point and this held onto the weaklink which consisted of multiple loops of thick line.

http://ozreport.com/9.037
Recommendations based on Robin's accident

Rohan Holtkamp - 2005/02/14

Recommendation One:

Do not use a 'Wichard' or 'spinnaker' release directly connected to a string or rope. This type of metal release has a metal knob on the opening arm that a rope will catch on, even when the release is activated and open.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3107
I have a tandem rating!!!

Lauren Tjaden - 2008/03/23 22:20:15 UTC

When Jim got me locked out to the right, I couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the F'ing release slid around when I tried to hit it.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3347
Tad's barrel release tested

Janni Papakrivos - 2008/06/30 15:35:44 UTC

With a bunch of tows to boot I can say that it happened once that I tried to release but missed the brake lever, instead I just pushed it around the down tube and had a much harder time reaching and actuating it.

http://www.hanggliding.org/weblog_entry.php?e=516

Rick Maddy - 2009/04/04 20:17:05 UTC

I actually went for the release just above tree level and missed. I hit the top of the release and knocked it sideways a little.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3648
Oh no! more on weak links

Carlos Weill - 2008/11/30 19:24:09 UTC

I tried to release but my body was off centered and could not reach the release. I kept trying and was close to 90 deg. All these happen very quickly, as anyone that has experienced a lock out would tell you. I heard a snap, and then just like the sound of a WWII plane just shut down hurdling to the ground, only the ball of fire was missing. The tug weak link broke off at 1000ft, in less than a second the glider was at 500ft.

http://www.hanggliding.org/viewtopic.php?t=11497
Aerotow release options?

Axel Banchero - 2009/06/20 04:57:01 UTC

I just kept hitting the brake lever for a few seconds in WTF mode, and the instructor used the barrel release.

Matt Taber - 2009/07/12

The primary release may fail at any time; this is why a secondary release must be used on all tows. Remember, you were trained to tug your primary only once before going straight to the secondary!

Sorry for interrupting, please continue...

Safety Tip: All releases should meet rigorous standards of reliability.

Yeah, the SHOULD, shouldn't they? But, hey, this is hang gliding - so you're just gonna DECLARE them to be safe and effective.

With a two-point bridle, it has become common practice to place a primary release at the attachment point on the glider as shown previously in figure 7-11. For safety reasons, a secondary release is placed at the pilot's shoulder straps.

The type of release used as a primary on the glider keel is usually a spinnaker hook activated by a bicycle brake cable and lever. These releases are made by various tow operations and are available for sale through ads in publications devoted to our flying sports. In fact, all the releases described here are designed specifically for hang gliding or paragliding and can be obtained within the flying community (see Appendix IV).

Yeah, right. They were "designed". It's not like a bunch of flight park shitheads just slapped them together out of whatever off the shelf crap they could get ahold of or had lying around.

APPENDIX IV

Useful Addresses

Here we provide a list of useful addresses as sources of towing equipment and information. Please note that these sources and addresses can change and we cannot possibly include every available source. We suggest pilots contact their national organization for more equipment sources.

TOWING ACCESSORIES

Austin Air Sports, Windmere, TX (210-693-5805) - Towing supplies
Blue Sky, Harrisonburg, VA (540-432-6557) - Towing supplies
Distance Design, Outremont, Quebec (514-343-9611) - Stationary winch
Fly High, Pine Bush, NY (914-744-3317) - Towing supplies
Graybird Airsports, Florida (352-245-8263) - Aerotowing
Cortland Line, Cortland, NY 13045 - Dacron trolling line for weak link material
High Perspective, Toronto, Canada (905-294-2536) - Towing supplies
Kentuckiana Soaring, Clacksville, IN (821-288-7111) - Towing supplies, Towing Chart of Reliability
Kite Enterprises, Allen, TX (972-390-9090) - European style double releases, scooter tow system
Kitty Hawk Kites, Nags Head, NC (800-334-4777) - Towing supplies
Lockout Mountain Flight Park, Rising Fawn, GA (800-688-LMFP) - Towing supplies *
Mountain Wings, Ellenville, NY (914-647-3377) - Towing supplies
Norm Lesnow's Flying Adventures, MI (248-399-9433) - Towing supplies
Quest Air, Groveland, FL (352-429-0213) - Aerotowing supplies
Raven Sky Sports, Whitewater, WI (414-473-8800) - Towing supplies
Wallaby Ranch, Orlando, FL (941-424-0070) - Aerotowing supplies
Williams Flight Systems, Seymour, IN (812-497-2327) - Towing supplies

* Yes, that IS how in appears on Page 372.

So great, Bill.

- You:

-- publish a book that a bunch of morons are gonna use as The Bible for towing to the end of time

-- give credibility to at least five individuals and seven major commercial operations using, training with, selling, flooding the market with this piece o' shit

-- undoubtedly flew with this piece o' shit in preparation for throwing this book together, despite the fact that it never got anywhere near ANY kind of testing - especially what you specify in Appendix III

-- illustrate the book with at least nine photos - including one on the back cover - and thirteen drawings in which this piece o' shit is definitely or pretty obviously being used

-- STATE that this piece o' shit has been PROVEN to be safe and effective.

- But maybe two to four years BEFORE you published you absolutely KNEW in no uncertain terms that it WASN'T - as anybody with half a brain or better coulda told just by glancing at it.

- And you tell:
-- people to UNDER NO CIRCUMSTANCES try to make their own - this is a job for the EXPERTS. And they've already done it.
-- tell everybody where they can go to buy these things.

- And then - over half a dozen years AFTER you flood the market with your advertisement for this crap - you get out on some shitty little closed access wire and make that statement about them not functioning even under the load of your sacred loops of 130 pound Greenspot.

Yeah, USHGA really has some fine people serving as Accident Review Committee Chairmen. I wish this organization had hundreds just like you - instead of the thousands it actually does.

And you too, Dennis.

[Tad Eareckson]

Figure 7-21: Hooking Primary Release to Carabiner

Release lanyard looped through carabiner. Note: Carabiner faces backwards in this application to avoid loading gate and hinge improperly.

Hey there, oh Master Of The Vector Diagram...

Let's use a steel Omega Pacific OP76S38L 7/16" Modified D Screw-Lok carabiner.

Let's turn it back around the way God intended it and hook in 250 pounds of pilot and gear under a 75 pound glider and free fly straight, level, trim. The carabiner's gonna be aligned major axis vertical and feeling 250 pounds - right?

Now let's connect in a Wallaby release and start towing with a 150 pound tension. Assuming a sixty degree bridle apex angle the carabiner will now be feeling 250 pounds straight down and 86 thirty degrees down from horizontal.

- How's the spinnaker shackle anchoring webbing gonna be able to climb up to the hinge? Where's the up vector coming from?

- What's the carabiner gonna be doing? Is it STILL gonna be vertical?

Everybody and his fucking dog knows that a single loop of 130 pound Greenspot is the ONLY safe weak link for a solo glider so let's surge the tension up to 226 and pray the loop survives to its max out point. So we've got 250 pulling straight down and 130 pulling thirty below horizontal.

How's the carabiner gonna be aligned?

Take it to one G of tension - the max allowed by Towing Aloft because beyond that the glider is capable of locking out. Now we're talking 187 coming through the bridle.

Take it up to two Gs - the max allowed by USHGA cause they don't care if the glider locks out. 250 down and 374 at the angle.

How's the carabiner gonna be aligned?

IF you answered still vertically AND the webbing has climbed up the gate AND the glider's gone into a dive so that the bridle is pulling perpendicularly on the hinge and/or gate... The carabiner's getting loaded minor axis 374 pounds. Its minor axis rating is 9 kiloNewtons. That's 2023 pounds. So at two Gs we're at 18.5 percent of the capacity.

So let's take the tow tension up to the point at which it could blow the carabiner minor axis - if it could possibly stay minor axis - which it couldn't. 3518 pounds of towline tension. Kinda makes you stop and think a little about what's going on with the Dragonfly at this point. For that matter, kinda makes you stop and think a little about what's going on with the glider. Of course if you had stopped and thought a little bit at all we wouldn't be having this IDIOT discussion.

Now let's stop and think for a fraction of a second or two what could happen to the bottom end of a parachute bridle when it tries to rip its way past a locking barrel if some fucking moron follows your fucking moronic recommendation. And while/if you're THINKING at all try to remember what happened on 2009/03/10 to the two occupants of a glider after the bottom end of a parachute bridle which DIDN'T hafta rip past a locking barrel failed at Queenstown after a reasonably benign opening shock.

Kinda like using backup suspension and quick links between your harness suspension and parachute bridle - make things more dangerous by playing engineer and fixing totally imaginary problems.

[Tad Eareckson]

A weak link is the focal point of a safe towing system.

Which, of course, is absolute rot. The focal point of a safe towing system is a hand or pair of teeth in constant contact with a release actuator.

Nevertheless, as vital as this "focal point" of a safe towing system is and despite the fact that:

We have witnessed a bridle whipping around the towline and preventing the towline from slipping off the bridle.

there is not a SINGLE reference to putting a weak link anywhere but on one end of a threading bridle. And there are about thirty illustrations depicting aerotowing - photos and drawings, two and one point - in which there is no or can safely assumed to be no secondary weak link where needed. And a weak link on one end only of a threading bridle of any length beyond a few inches isn't a weak link - it's a gamble link that frequently fails to pay off.

So apparently the focal point of a safe towing system really is of no concern whatsoever following a wrap. Funny, I'da thunk that that's EXACTLY when a weak link would be MOST likely to become a safety consideration.

So, Dennis and Bill...

What you're saying is that a weak link is critical to your safety - except when it's critical to your safety. Then it's of no importance 'cause you've got a Bailey Release that can handle anything (as long as no tension is involved) and a hook knife if that doesn't work.

[MikeLake]

What is the problem with a weak-link in the tow line?
I've read several times now comments such as "We don't use weak-links in the towline any more". Why?

Tow line ..... weak-link .... flappy stuff & other gear ...release
If the weak-link is out in front of the glider you get at least another chance should any of the flappy stuff wrap, however you finally attach yourself to the glider.

You also only need one weak-link instead of introducing additional ones to cover a variety of different ways the first one might not work.

The only reason I can see for not having the weak-link in the tow line is you can't (easily) have a personal one.
However, from what I can gather everyone uses the very same 'personal' one, so what is the point?

Why not put one weak-link in the tow line strong enough to satisfy the biggest f***er you have and be done with it? (rhetorical)

[Tad Eareckson]

The main benefits of the single point bridle is its simplicity and its tendency to reduce yawing of the glider under tow.

- Right. Single point towing REALLY reduces yawing. I have NO IDEA why we put new pilots up two point when we could be giving them this extra safety edge.

- What effect does the single point bridle have on the tendency to reduce yawing of the glider NOT under tow?

The latter effect results from the fact that the location of the forces on the glider is similar to that when in free flight.

Bullshit. In one point towing ALL of the tow tension is going to the hang point. Look at your drawing in:

Figure 7-11: Two-Point Aerotowing Bridle

on the previous page.

What you're obviously not getting is that ALL of the tow tension is going to the hang point there as well.

You're obviously not getting it 'cause even though half the tow tension is pulling the pilot forward you've got him hanging straight down - as he would be in free flight.

And there's no way the bridle's gonna look like that either - the apex is gonna be at about the middle of the run between the shoulders and the hang point and it tends not to shift around more than about an inch either way during a halfway sane tow.

Getting back to reality for a moment or two... Let's say you wanted to DELIBERATELY introduce yaw instability to tow configuration. Aside from connecting to the keel aft of the hang point, how could you possibly do it?

Another advantage is that it is short and thus easier to tuck away into your harness. One drawback to single point is that it is not easy to incorporate a secondary release...

Right. If you put a barrel release a between your right shoulder and right end of the bridle I simply cannot IMAGINE any way or place to add another release. Perhaps if we got a crack team of USHGA officials and flight park operators, took away their crack, and let them brainstorm the problem for ten or fifteen years...

...so a hook knife MUST be handy in flight.

Yeah. Do what Shane Smith did 'cept ALWAYS keep the hook knife handy. Use a very very reliable bent pin release like the one all those people and flight parks in your acknowledgements and recommended equipment suppliers sell and you assholes fly with and dutifully illustrate in Figures 2-16 and 7-12, use a bridle ten times too long and otherwise poorly constructed, and take the ring off the end of the towline. But... KEEP THE HOOK KNIFE HANDY.

Better yet... Make it a USHGA REGULATION that the pilot MUST hold a hook knife in his teeth for every one point tow launch. Did you ever watch a pirate movie? THOSE people knew how to carry a knife so's they could get to it in a hurry. IF ONLY Shane had had a hook knife in his teeth.

But wait a minute!!!

As discussed above, aerotowing is a constant speed form of towing and the tow forces can vary dramatically in response to thermals, sink, pilot actions, etc. A weak link is required that will not break needlessly in response to moderate thermals, or pilot inputs, yet will break at a low enough point to avoid disaster or excessive pilot panic.

FORGET the secondary release, straight pin, short bridle, tow ring, and handy hook knife. Just use a weak link that will break at a low enough point to avoid disaster or excessive pilot panic. If ONLY Shane had used a weak link that would've broken at a low enough point to avoid disaster or excessive pilot panic! The solution to ALL of these release and bridle problems is SO SIMPLE!!!

[Tad Eareckson]

Oops. Sorry Mike, didn't see your post before my last.

The way things are done in US Dragonfly towing there is RARELY a real weak link anywhere in the system.

There's a weak link at (or near) the top end of the Dragonfly bridle and nothing on either the bottom (release end) or the end of the towline. So we can and, obviously, DO get THIS:

I witnessed a tug pilot descend low over trees. His towline hit the trees and caught. His weak link broke but the bridle whipped around the towline and held it fast. The pilot was saved by the fact that the towline broke!

That's one of the must infuriatingly stupid quotes - Towing Aloft, Page 349 - I've ever seen in hang gliding (and, as we both know all too well, there's a lot of really excellent competition out there).

On the glider there's a weak link on the top (release) end of the two point bridle. It can and does wrap and thus that weak link is taken out of the equation. And the more tension the more likely you are to have a wrap so you're MOST likely to have a wrap when that weak link blows.

Now you're towing one point, from your shoulders only - as you would have been if you deliberately launched that way. There are still a lot of gliders - particularly the morons who listen to total assholes like Dr. Tracy S. Tillman - who now no longer have a weak link at their end - or anywhere if the tug has had a wrap - and may already be in bad shape alignment-wise in the remote possibility that the 130 pound Greenspot DIDN'T blow when things were straight and level.

Starting only a few years ago most of the flight park assholes got people putting A weak link on ONE end of the secondary bridle - as they would have them configured for deliberate one point towing. But the weak link was typically on one harness aerotow loop connecting an excessively long, poorly constructed bridle, running to a very very reliable bent pin release on the other shoulder, which was supposed to be able to feed through a soft eye at the end of the primary bridle - which is now an extension of the towline.

This is not quite as bad but very similar to the configuration that killed Shane three months ago yesterday.

And this is EXACTLY how Lookout, Wallaby, and Columbus had Zack configured until very recently.

And even WITH a tow ring...

http://www.hanggliding.org/viewtopic.php?t=14230
pro tow set-up

Jim Rooney - 2009/11/02 18:58:13 UTC

Oh it happens.
I have, all the guys I work with have.
(Our average is 1 in 1,000 tows)

Oh yeah... an other fun fact for ya... ya know when it's far more likely to happen? During a lockout. When we're doing lockout training, the odds go from 1 in 1,000 to over 50/50.

So if you get that wrap after a strong pull you've got a weak link but no release and if you get it after a pop - which is most likely - you have a very very reliable bent pin release (assuming the pin hasn't folded in half inside the barrel - yet) but no weak link.

And this despite our own regulations which clearly state:

The United States Hang Gliding and Paragliding Association, Inc.
Standard Operating Procedure
12. Rating System
02. Pilot Proficiency System
10. Hang Gliding Aerotow Ratings
-B. Aero Vehicle Requirements

05. A weak link MUST be placed at BOTH ENDS of the FUCKING TOW LINE.

(Alright, I altered it just a tiny little bit.)

When a trike with no bridle is involved there IS a weak link on the front end of the towline 'cause there's no other place to put it.

When a glider with a closed bridle (release at the bridle apex) is involved there IS a weak link on the back end of the towline 'cause there's no other place to put it. (Note: There are only three or four Hewett Disciple whack jobs out in the boondocks who actually fly this way.)

You will NEVER find a weak link on either end of the towline at a Dragonfly operation.

In Towing Aloft there are ZERO references to or illustrations of a weak link on either end of the towline in which there's a Dragonfly at the front and/or a glider with an opening/threading bridle at the back.

That being said...

The only reason I can see for not having the weak-link in the tow line is you can't (easily) have a personal one.

Nah, with respect to the back end aerotowing anyway there's actually a good reason - it gets dragged. So you either gotta use a (bulky, heavy) Tost weak link or watch a string job like a hawk every flight.

You also only need one weak-link instead of introducing additional ones to cover a variety of different ways the first one might not work.

But there's virtually no cost, absolutely no danger, and a HUGE advantage to doing it that way.

First, there's only one way a weak link gets taken out of the equation - bridle wrap.

Let's start with the Dragonfly. Ideally it should be configured with a release system like the glider - primary release at the top of the tow mast / bridle, secondary at the back end of the fuselage.

BUT...

- The engineering to do a top end release would be a royal pain.

- If a glider releases from the bottom end and gets a wrap he instantly finds himself in Bart Doets mode at best or Peter Roth (vertical dive, structural failure, parachute, prayer) mode at worst. On the Dragonfly it's no BFD.

- Dragonflies very rarely squeeze the lever, should squeeze it a lot MORE rarely (so they don't kill people like Rob Richardson as often), and thus have problems so rarely that they're virtually nonexistent.

So what they SHOULD but are too incredibly stupid to be doing is putting a 300 pound weak link at the top and a 360 pounder on the bottom. That way if there's an overload and a wrap the problem fixes itself.

On the glider you do the same thing so that you're about one and a half Gs normally and use a twenty percent increase from top to bottom, either by using a Bridle Link or string loops at BOTH ends of the secondary / one point bridle. If you have a wrap after a release you're ALMOST certain to be off tow automatically and after an overload you're ABSOLUTELY certain to be off instantly.

Why not put one weak-link in the tow line strong enough to satisfy the biggest f***er you have and be done with it? (rhetorical)

Ignoring (rhetorical)...

No no no no. Simply not done that way, old boy. We DO have concern for the safety for all but the lightest of our pilots - usually small girl types.

So we use a weak link that never blows for the smallest f***eress we have and blows every other tow for no reason for the rest of us to prevent lockouts and give us the option of getting off tow by pitching out abruptly when - for some totally inexplicable reason - we get into lockouts anyway.

The selection of the breaking threshold is not an exact science. Rather it is a subjective decision based upon the method of towing, the tow tensions being used, the loading on the glider and simply the comfort level of the pilot.

See? It's a MUCH more complex issue than you take it to be. It's not like sailplaning in which the manufacturer just specifies a weak link for a model based solely upon structural considerations with no concern whatsoever for the tow tensions being used and the comfort level of the pilot.

[Tad Eareckson]

Tug Releases

For types of tugs such as the Moyes Dragonfly, the release is attached to the tail of the craft in the manner shown in figure 7-16. Fastened to the top of a pylon at the tail is a bridle that routes through the loop or ring on the towline, then hooks into the release. This arrangement allows the bridle to clear the aircraft's control surfaces (rudder and elevator and also lets the tow rope move up and down the bridle, thereby reducing the effect on the tug control if the glider is too high or too low, as shown in figure 7-17 (more on this later).

---
Figure 7-16: Fixed Wing Tug Bridle and Release System

Ultralight tug tail
Forward support cables
Weak link
Bridle loop
Tug bridle
Bridle slips through towline loop when released.
Towline
Towline loop
Release
---

One important consideration with this type of release (and all releases) is that it must release in all situations. Since the bridle pulls up on the release, it can cause a greatly increasing release force as the pilot gets higher. As figure 7-18 illustrates, the bridle pulls the hook lever upward, making it more difficult or impossible to pull the release. Some sailplane accidents have occurred due to this effect. The simple cure is to allow the whole release to angle upward as shown in the figure, or turn it upside down (the latter arrangement is approved by the FAA in the U.S.). When this two-point bridle system is released, the bridle slips through the tow rope as figure 7-16 illustrates. We have witnessed a bridle whipping around the towline and preventing the towline from slipping off the bridle. For this reason a weak link must be added to the top of the bridle.

---
Figure 7-17: Tug Bridle Effects

Ultralight tug tail
When glider pilot is too high, towline moves up bridle.
When glider pilot is too low, towline moves down bridle.
---

Fastened to the top of a pylon at the tail is a bridle that routes through the loop or ring on the towline...

So why would anyone in his right mind use a loop - unless a sailmaker's thimble were installed, which it isn't - instead of a ring?

Bridle slips through towline loop when released.

Yeah, that's the assumption.

I witnessed a tug pilot descend low over trees. His towline hit the trees and caught. His weak link broke but the bridle whipped around the towline and held it fast. The pilot was saved by the fact that the towline broke!

Just don't bet the farm on it - especially when the shit hits the fan.

One important consideration with this type of release (and all releases) is that it must release in all situations.

Really? Even in hang gliding?

http://ozreport.com/forum/viewtopic.php?t=22660
What can be learned from this "scooter" towing accident?

Jim Rooney - 2011/02/06 18:35:13 UTC

I don't really have anything against the Kotch release.
I think it's big, clunky and expensive, but I'm sure it works fine.
I'm also sure it has it's problems just like any other system. The minute someone starts telling me about their "perfect"system, I start walking away.

I have it on the VERY BEST of authority - someone with a keen intellect/knowledge of the issues when it comes to most things in general and hang gliding AT/Towing in particular - that this is simply beyond the scope of human engineering.

Since the bridle pulls up on the release, it can cause a greatly increasing release force as the pilot gets higher. As figure 7-18 illustrates, the bridle pulls the hook lever upward, making it more difficult or impossible to pull the release.

What happens when you pull it sideways? Doesn't it make it STILL more difficult or impossible to pull the release?

Some sailplane accidents have occurred due to this effect.

Yeah. Extremely fatal ones.

The simple cure is to allow the whole release to angle upward as shown in the figure, or turn it upside down (the latter arrangement is approved by the FAA in the U.S.).

Yeah, that's the "simple" "cure" - 'cept it does NOTHING to address the side loading issue.

Or you could do it right and use a Tost release which doesn't give a rat's ass about alignment or - far beyond the survivability of the aircraft - loading.

We have witnessed a bridle whipping around the towline and preventing the towline from slipping off the bridle. For this reason a weak link must be added to the top of the bridle.

- Added. That implies there's another one somewhere around. I seemed to have missed that bit. Where is it?

- I'm also having some trouble understanding how this "simple cure" really fixes the problem. You've tried to release and have a wrapped bridle. So now you can be one hundred percent CERTAIN that this weak link is gonna blow to prevent anything bad from happening to you?

- Have you ONLY witnessed a bridle wrapping after being released from the bottom? Have you EVER witnessed a bridle wrapping after the weak link at the top blew? If not, can you CONCEIVE of such a scenario? If yes what's limiting the load on the Dragonfly and its release?

- What part of:

A weak link must be placed at both ends of the tow line.

do you fucking morons not understand?

- Assuming that sentence is way beyond your scope, what's stopping you fucking morons from ADDING a weak link to the BOTTOM end of the bridle?

[Tad Eareckson]

Bob,

On Sunday I asked you (on the phone - nobody search) to look at the lower photo on the back cover of Towing Aloft and tell me where the release actuator was. Lemme reiterate a bit of and expand on that discussion...

Your (disappointing) immediate response to give Wallaby (this IS a Wallaby release and that IS a Wallaby photo (there's a smaller black and white copy on Page 64 - "Courtesy of Wallaby Ranch") the benefit of the doubt and suggest that there might be a valid and rational reason for velcroing a brake lever to the starboard downtube.

This:

http://ozreport.com/forum/viewtopic.php?t=14221
Tad's release

John Fritsche - 2008/12/12 05:38:02 UTC

Do people still use those (IMO, stupid) releases that involve bicycle brakes?

was the reaction you should've had. That was a very mild version of my reaction upon my first glimpse - I was completely dumbfounded at the astonishing stupidity of the piece of crap. It represented such an unbelievable retreat from the common sense configuration we were using in 1991.

This:

http://groups.yahoo.com/group/skysailingtowing/message/4411
Keel Attachment

John Moody - 2004/12/16 23:07:36 UTC
Conroe, Texas

What is not normal is to see a factory-made glider that has a built in nose attachment or keel attachment or even the keel release built-in, faired and clean - like a VG system is.

So why does Mr. Reynoldson have to ask where to attach his tow line? ATOS has to know that their gliders are being towed every day. Why does each pilot have to figure it out, one at a time. Why don't the manufacturers sell a TOWING version of their gliders and avoid someone getting it wrong?

is EXACTLY how things would be done in a sane universe. That's EXACTLY how I implemented my own system - which is the only two point aero system I entirely trust.

Wallaby just shitrigged a bunch of easily obtainable and inappropriate components together to get something that worked three quarters of the time - as long as nothing unpleasant is happening.

http://groups.yahoo.com/group/hhpa/message/9351

John Moody - 2010/02/03 04:09

What Tad argues is that most of our releases are poorly constructed and engineered, (more as in Not Engineered). That was what he was trying to show on the Flickr site. I went back to that site and re-examined the photos and was able to see how he was trying to show how so many of our releases fail to release properly or are hard to operate. That includes the barrel releases and the spinnaker releases we use around here.

For example the spinnaker release we all use was designed for sailboats and it can, will, and has failed - I have seen it do exactly what Tad said it did.

That's why you NEVER hear about a malfunction of a VG system - which is totally non critical - while the Wallaby release...

http://www.hanggliding.org/viewtopic.php?t=11497
Aerotow release options?

Axel Banchero - 2009/06/20 04:57:01 UTC

I just kept hitting the brake lever for a few seconds in WTF mode, and the instructor used the barrel release.

...does that kinda shit so often that it's just considered no BFD, part of the background noise.

http://groups.yahoo.com/group/hhpa/message/11192

John Moody - 2010/09/21 03:30:45 UTC

In industry, they called that THE NORMALIZATION OF DEVIANCE. In other words, if something (wrong) happens often enough, we begin to treat is as NORMAL and go on with our lives.

And that WAS a Wallaby release and on a Wallaby tandem trainer.

But this:

http://groups.yahoo.com/group/TUGS/message/1149
aerotow instruction was Re: Tug Rates

Tracy Tillman - 2011/02/10 20:08:32 UTC

Hey Tad.

Anybody who is truly a good pilot, in any form of aviation, knows that the knowledge, skills, and judgement you have in your head, learned from thorough instruction from a good instructor with a good curriculum, are the best pieces of equipment you can fly with. Good equipment is important, the best equipment is a well-trained brain.

is USHGA so we're just supposed to use whatever shitrigged junk the Flight Park Mafia deems to make available and allow us to fly, then pay them to train us how to fly a glider with one hand, always release the towline before there is a problem, use weak links which will break before we can get into too much trouble and backup releases and hook knives for when they don't, pitch out abruptly to blow the weak link, and not fly in conditions in which we'd need actual good equipment.

It's not designed for the safety of the pilot. It's not designed to work. It's designed to be easily fabricated, easily slapped on and removed from any glider, and easily sold. The reason the lever is on the downtube - instead of where it should and needs to be - is because that's where it most easily fits and, because you've got one less bend in the cable, is less likely to malfunction.

And it doesn't seem to matter that not only can you not get to it without compromising or losing control...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3648
Oh no! more on weak links

Carlos Weill - 2008/11/30 19:24:09 UTC

I tried to release but my body was off centered and could not reach the release. I kept trying and was close to 90 deg. All these happen very quickly, as anyone that has experienced a lock out would tell you. I heard a snap, and then just like the sound of a WWII plane just shut down hurdling to the ground, only the ball of fire was missing. The tug weak link broke off at 1000ft, in less than a second the glider was at 500ft.

...you may not be able to get to it period while you're still in control of the glider.

You suggested that the lever might be on the downtube for a valid reason - like avoidance of accidental release.

- I countered that in 1974 (an era in which EVERYBODY was properly absolutely terrified of accidental release) ALL tow configurations included a release lever at one or both hand positions on the basetube.

Additionally...

- Often Wallaby release levers ARE on the basetube.

http://www.moyes.com.au/productdetail.asp?ID=42&Cat=Accessories

A Moyes release is the exact same assembly as the Wallaby.

http://ozreport.com/forum/viewtopic.php?t=1143
Death at Tocumwal

Davis Straub - 2006/01/24 12:27:32 UTC

Bill Moyes argues that you should not have to move your hand from the base bar to release.

-- Know who Bill Moyes is?
-- See where the lever is?
-- See where the wheels are?
-- Think a pilot should hafta make a choice between getting killed on tow and getting killed on landing?
-- Can you think of a better way of doing that, Mister Aeronautical Engineer?
-- (Have any idea why they have the basetube on backwards?)
-- Ever hear anyone who's not a total lunatic advising NOT putting the lever on the basetube.
-- Ever hear of anyone having an accidental release because of an actuator on the basetube?

Wallaby Ranch - 2011/04/19

If you fail to maintain the correct tow position (centered, with the wheels of the tug on the horizon), the weak link will break before you can get into too much trouble.

http://www.hanggliding.org/viewtopic.php?t=12536
standard operating procedures

Axel Banchero - 2009/06/18 15:42:14 UTC

I have had one weak link break during launch and I feel "lucky" everything went well and just landed a bit hard on the wheels.

But I also saw a world class pilot having exactly the same problem and breaking the link at the same altitude. But he broke the downtubes on his Litespeed and looked to be in pain in one of his wrists. He was fine though.

I saw more weak links break at low altitude and it is always a few seconds of anguish and uncertainty about what's gonna happen to the pilot.

-- If accidental releases can be deadly (which they can) how come it's no BFD for Wallaby to be putting everybody up on weak links so light that they blow at random?

-- Towing Aloft, Figure 7-20, right drawing. Where's the lever, where's the disclaimer about the dangers of accidental actuation, where are the wheels?

- Find me a non daguerreotype photo of a bicycle which requires the rider to take a hand off the handlebars to be stopped. Find me a photo of a non coaster brake bicycle that doesn't have two levers immediately accessible from normal positions of the hands. Ever hear of a kid accidentally braking when he hits a pothole? How 'bout a motorcyclist accidentally engaging a front brake or disengaging a clutch?

And after nearly thirty years of mainstream aerotowing we can't do as well or better?