Airborne release

[deltaman]

Airborne sell this release at the prewords (Forbes)

http://www.flickr.com/photos/psucvollibre/6634370899/

[Tad Eareckson]

Some level of sanity finally making inroads on the mainstream.

Comments...

- I want credit for being the first person to use a:
-- straight pin;
-- leechline (versus webbing) body;
-- narrow, straight (versus flared) barrel; and
-- heat shrink grip.

- I wonder if my photo site had any influence on that design.

- The pin shaft appears to be longer than that of my stock M111S. That's good.

- The pin shaft comes off the eye tangentially rather than perpendicularly. That's bad - and probably cancels out the mechanical advantage of the greater length. It allows more of an offset between the leechline body and the weak link and reduces the load required to distort/damage the pin - the Weghorst issue illustrated by Photo 6:

http://www.flickr.com/photos/aerotowrelease/8331326948/


of the:

http://www.flickr.com/photos/aerotowrelease/sets/72057594066304861/detail

sequence.

- They were smart enough to eliminate the flaring at the front end of the tubing.

- They were stupid enough to retain the flaring at the back end of the tubing. The back end of the tubing MUST be beveled but the ONLY thing the flaring does is increase the propensity of the barrel to catch on the basetube and autorelease.

- They were also stupid enough to retain Bobby's idiot barrel length - geared to accommodate the length of the pin it's retaining rather than the width of the hand that's gotta grab and pull it. And...
-- If any part of the pilot's hand is in front of the barrel it's gonna get hit by the pin as it rotates to release.
-- The pilot's hand is guaranteed to be hit by the pin when it continues rotating (back) after disengaging the weak link.

Because the Bailey Release has such abysmal mechanical advantage the curved M111C pin doesn't rotate with much speed/force/energy but that straight pin WILL do some damage at a high tow load. If you're releasing in a high load situation you're probably not gonna be too worried about the blood blister or cut you're gonna get if you don't grip a four inch barrel aft of the pin's recoil range but it's stupid to make the barrel so short that you make the hit a guarantee.

- Unless the heat shrink is glued on it won't stay put after a lot of use.

It's (obviously) a huge improvement on the idiot Bailey Release and, even if no weak links were used anywhere in the system, it would be very unlikely to ever see enough load to make its deliberately built in shortcomings seriously consequential. So this thing will probably catch on, tangential pin shafts and short barrels with flared aft ends will be the standard for the next thirty years, and the Airborne guy who put this thing together will be declared by one and all as a genius way ahead of his time.

Can hardly wait to hear Rooney giving his expert opinion on the new miracle release while his hordes of adoring zombies hang on every punctuation mark.

[deltaman]

The pin shaft comes off the eye tangentially rather than perpendicularly. (..) It allows more of an offset between the leechline body and the weak link

Perhaps it is thought and made to connect the eye of the V-bridle directly to the release but surely it is also thought and made like this to avoid the mistake of a lateral rotate of the pin when set up.

PS: I have got my spies at Forbes and asked for report on every atypical system of release and AT incident/accident.

[Tad Eareckson]

Perhaps it is made to connect the eye of the V-bridle...

The nautical definition of a bridle is:

a length of rope, chain, or cable fastened at both ends to an object that is to be secured or moved or to a vessel that is to do the towing, a pull being exerted at the center of its length.

That's totally consistent with our aeroNAUTICAL employment of the device.

It's a length of rope fastened at both ends which ALWAYS runs through a ring at the back end of a towline or eye at the bottom end of another bridle or, less ideally, has a release mechanism fixed at its center.

ALL bridles when functioning on tow have tension applied at or near their centers and they ALL form Vs.

So saying V-bridle in hang gliding is like saying snow blizzard in meteorology because we don't need to differentiate from B-bridles or rain blizzards.

In hang gliding the term V-bridle is used almost invariably to refer to the primary bridle in two point - pilot and glider - aerotowing. That's best referred to as a primary or two point bridle. The secondary or, if you're towing pilot only, one point bridle DOES also connect to two points - the pilot's shoulders - but they're two very narrowly separated points on the same object so one point is good and can't be misunderstood.

So anyway...

This release is not being used to connect to an end of what is commonly referred to as a V-bridle. It's being used to connect to an end of a secondary, one point, shoulder to shoulder, or (gag me with a spoon) "pro tow" bridle.

...directly to the release...

- That would be an EXTREMELY bad idea. I one hundred percent guarantee you that nobody stupid enough to use a release like this is smart enough to use a short, fat, wrap-proof one point bridle with a weak link on the other end at the other release (or Bridle Link) and, if one has any brains, one NEVER employs a release which isn't weak link protected at all times no matter what.

- This material:

http://www.flickr.com/photos/aerotowrelease/8311348069/


has a breaking strength of one thousand pounds. Assuming nothing else in the bridle/release assembly blows first that bridle's capable of folding up the glider. How much fatter a line do you really need?

- If you really did want to connect to a fatter line the perpendicular shaft would still be the better, stronger, safer way to do it.

...but surely it is also made like this to avoid the mistake of a lateral rotate of the pin when set up...

- This is a totally imaginary, fictional mistake. Nobody's ever actually made it when hooking up to a tug.

- If you really wanna make this thing idiot resistant you do what I have done - you limit the allowable aft travel of the barrel. You don't modify the design to make it more dangerous BOTH for the non idiots who've doing things right all along AND the idiots you're trying to discourage from expressing their stupidity as much.

- While this "design" would probably DIScourage an idiot from flipping the pin - which nobody does - it also ENcourages idiots to fly without weak link protection - which is a very common Flight Park Mafia practice, heavily endorsed by Dennis Pagen and Bill Bryden in their excellent book, Towing Aloft.

- This "design" came about for one reason only - it looks like the rather dangerous Schweizer sailplane release. That's the problem with Bobby's idiot bent pin release and that piece o' crap you got from Matt. It's not "designed" to do a job, it's "designed" to look like what people think a release should look like.

I have got my spies at Forbes and asked for report on every atypical system of release...

Tell them to keep the shadows of their heads out of the photos in the future.

...and AT incident/accident.

This event is being controlled by Davis and the usual flock of other assholes. I do hope they'll have opportunities to get a few flights in as well. (Tell them to double up their weak links when nobody's looking and bribe the launch monitors. That'll help.)

[Steve Davy]

...you limit the allowable aft travel of the barrel.

What is/are the reason(s) for doing this?

[Steve Davy]

...which is a very common Flight Park Mafia practice, heavily endorsed by Dennis Pagen and Bill Bryden in their excellent book, Towing Aloft.

Ok you lost me there. Thought Dennis was saying "A weak link is the focal point of a safe towing system."

Edit:

...configure them in violation of USHGA towing regulations so they don't work when you actually need them to.

I re-read your thread "Towing Aloft". I'm still not clear about "it also ENcourages idiots to fly without weak link protection".

[Tad Eareckson]

What is/are the reason(s) for doing this?

http://www.flickr.com/photos/aerotowrelease/8305308635/


Barrel Release, second from bottom.

I make my Barrel Releases a standard minimal length and then extend them from their mountings a desired or necessary length using some sort of Adjuster:

http://www.flickr.com/photos/aerotowrelease/8312203997/

http://www.flickr.com/photos/aerotowrelease/8312206905/

http://www.flickr.com/photos/aerotowrelease/8312208727/

http://www.flickr.com/photos/aerotowrelease/8312211409/

http://www.flickr.com/photos/aerotowrelease/8313263612/


To keep the front end of the Adjuster from getting damaged by the back end of the Barrel as a result of repeated hard pulls, I install a Stop - a short sleeve of vinyl tubing - over the leechline Body of the release aft of the Barrel.

If I fix the position of the Stop as far fore as possible while allowing the Barrel to fully clear the Pin in a slack line situation it makes it difficult - but not impossible - to close the Barrel over the Pin when it's been flipped - versus rotated - back to retain the Weak Link - as you have illustrated here:

http://www.flickr.com/photos/psucvollibre/5958248335/

The reason this works is because when you (properly) ROTATE the Pin it only extends back the length of its shaft. And when you (improperly) FLIP the Pin it extends back its OVERALL LENGTH - the length of the its shaft PLUS the length (diameter) of the its eye.

So limiting the allowable aft travel of the Barrel with the Stop DOES make the Barrel Release idiot resistant at no additional cost in materials, construction effort, complexity, weight, or drag. But that's not THE REASON for that aspect of the design. THE REASON is to protect the assembly from damage and wear. And if that reason didn't exist I wouldn't add the Stop Assembly just to cater to people too stupid to properly engage a barrel release.

And I never discuss the flipped pin "issue" unless somebody brings it up 'cause it's:
- not an actual issue anyway; and
- a really bad idea to show people how to do something wrong.

(On the latter... Like it's a really bad idea to teach people that hang checks and/or Aussie Methodist assembly procedures help prevent people from launching unhooked.)

Note that with the perpendicular pin loaded up:

http://www.flickr.com/photos/aerotowrelease/8312399698/


(to 400 pounds in that photo) the Body line (green and white) and Bridle Link line (red) are being mashed together, so damn near all the tension is going to trying to compress that area of the eye - which it can't do - and you're minimizing the vector of the tension going to torque the pin and thus distort it and jam its end into the Barrel wall. The tangent pin is is way less optimal in those regards.

Ok you lost me there...

In the 1997/02 issue of the magazine I've got a letter to the editor published which says, amongst a couple of other fairly obvious issues, that if you only have a weak link on one end of a long bridle and that end of the bridle wraps at the tow ring (after a release or weak link failure) you no longer have a weak link in your system. So you need weak links above and below or on both sides of a tow ring on any bridle long enough to wrap (and if it's a two point bridle the weak link at the bottom has gotta be stronger than the one at the top).

Then eleven months later Dennis and his evil idiot sidekick publish their evil idiot book. It DOES include descriptions and illustrations of configurations in which the weak link is installed at the downwind end of the towline. That's fine - the glider and any of its releases are protected at all times no matter what. But with respect to configurations in which there's nothing on the towline (like ALL aero in the US and Australia) try to find a single instance of a requirement for, reference to, illustration of a redundant or secondary weak link ANYWHERE between the covers.

Towing Aloft towing is safer than pushing the volume control button on your remote 'cause the safer it is the more people will do it, give their money to the Flight Park Mafia, join USHGA, buy copies of Towing Aloft, and tell all their friends how incredibly safe towing is.

In Towing Aloft towing the ONLY way a bridle end can fail to clear a tow ring is if someone were stupid enough to have installed on it a Tjaden Link - similar to the one illustrated on Page 60. So the ONLY reason one needs a "BACKUP" release is because it's beyond the capabilities of human engineering to design a primary release capable of functioning more than about three out of four tows and there's no danger whatsoever with using the backup as a primary 'cause - since there's no weak link on the bottom end of primary bridle - it's incapable of tying itself to the tow ring and leaving you instantly being towed by the keel with the full towline tension.

And on Page 291 you have:

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

depicting a Dragonfly bridle/release system with the:
- weak link at the top end of the bridle engaging the tow mast and
- bridle running through an eye at the front end of the towline and back down to the
- Schweizer type release coming off the back end of the fuselage tube.

And there's the assurance that the:

Bridle slips through towline loop when released.

But meanwhile, back in the REAL world, a bit of which they advertently include on Page 349:

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!

we see that - especially when the shit hits the fan - the fucking bridle tends NOT to slip through the towline loop when released. Which is why the fucking regulations say to put the fucking weak link on the end of the fucking towline and why I've been saying that if you don't put a fucking weak link on the end of the fucking towline then have fucking weak links on BOTH ends of the fucking BRIDLE so there's no possibility of a 250 foot length of two thousand pound spectra becoming your fucking weak link.

I can't think of a more blindingly obvious illustration of a more blinding obvious common sense issue yet, here we are at the beginning of 2012 and all Dragonflies are still configured the way that one was. (Really wish Charles Darwin would get off his fat ass and do his job on these guys often enough to get the point made clearly enough for people to start getting it.)

Seven and a half years after my letter, on the Capitol club rag...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=939
Weak link breaks?

Daniel Broxterman - 2005/08/26 14:28:42 UTC

While we're on this topic...at Wallaby in April the launch crew put a 2nd weak link in my system between the bridle and the Bailey. I fly with a two point, Wallaby-style release, with a single Bailey secondary. As I recall, here's the scenario they had in mind:

Pilot releases with primary, bridle catches on the tow line or release mechanism. If pilot becomes extremely out of position, the additional weak link would probably breaks prior to pilot finding and Bailey.

Does anyone else use two weak links, one on each release point?

Yeah Daniel, I said something like that - in English which would've gotten me through third grade and without the crap about catching on the release mechanism, getting out of position, and finding Baileys - seven and a half years before but nobody listened.

So at the 2006 ECC in early June at Ridgely Dennis is flying one point with a Bailey mounted on his (call it) right shoulder and an overly long spectra bridle connected to his left. Loop of 130 pound Greenspot engaging the Bailey. (His flying weight is 255 hook-in plus glider (and I was still a 130 pound Greenspot zombie at that point in history).)

I'm setting him up with a pair of my Barrel Releases. He's worried about engaging the somewhat bulky bridle end with the left Barrel Release. I tell him I'll just slap on another weak link. He has this huge lightbulb moment. Obviously such a bizarre idea had never occured to him.

Likewise...

Knowing nothing about hydraulic cylinders I was trying to gear up for some in-flight and bench testing.

Towing Aloft, Page 116:

The small, cheap cylinders manufactured by Boston Gear, Flair Line, Bimba, Humphries and other manufacturers work well. Diameters between 1 1/8 and 2 inches and strokes between 2 and 3 inches are appropriate.

I wanted to go as small and light as possible, had my eye on a Bimba 1 1/16 inch diameter cylinder with a one inch stroke, and wanted to know why two to three was being recommended. Could find no one who could tell me so when I finally crossed paths with Dennis I asked him. No freakin' clue. It was obviously just something somebody had told him so he just scribbled it down and published it. (I understand hydraulic cylinders now, by the way, and a one inch stroke is just fine.)

Sorry. Way too long an answer.

It's ESSENTIAL to have a weak link in your system at all times - even though you're probably not gonna have any need for it in a hundred lifetimes - but the Industry Standard idiots who are so insistent that the purpose of the weaklink is to increase the safety of the towing operation - PERIOD - are mostly loath to configure such that you actually HAVE one when you're MOST likely to NEED one.

[Tad Eareckson]

I dumped my last post moments before you edited your last (but did see it before clicking submit).

In case you're still not clear on how some of these releases encourage people to fly without having them weak link protected in the event of two or one point bridle wraps...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3035
Tad's Barrel Release and maybe an alternative

Jim Rooney - 2008/02/13 09:06:35 UTC

Oh..... in failing to answer my "what advantage does a straight pin have" question... you attempt to reverse it to "what advantage does a curved pin have".

Well, two things....
One... no one's trying to improve on your design. The bar was set with the Bailey... it is to YOU to "improve", which you have not done.

http://www.hanggliding.org/viewtopic.php?t=21033
barrels release without any tension except weight of rope..

Bart Weghorst - 2011/02/25 19:06:26 UTC

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.

Two... The advantage of a curved pin... it can handle differing thicknesses of materials. Yours can't. You have a very narrow range and then you run into the problem of that pesky stop. That's why yours have weaklinks on both ends... nice and thin.

Call it insignificant if you will, but YOU are the one that is the incumbent... the onus is on you, not Bobby.

Tad Eareckson - 2008/02/24 19:31:25 UTC

With respect to your assertion that my straight pin barrels can't handle differing material thicknesses...

I closed my personal copy over a loop of 3/8 inch Yale Crystalyne (11500 pounds) and it worked fine. Exactly what are you trying to tow with yours?

And, no, I don't have weak links on both ends - I don't use weak links as you define them. But, in any case, what's your point? Why wouldn't anyone who had done the walnut thing want the redundancy and why would anyone want to increase the material diameter and thus the side loading on either a curved or straight pin release?

And no response.

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?

Jim Rooney - 2011/08/26 17:34:33 UTC

Try fitting a straight pin release with anything but weaklink. (it doesn't quite fit the same) OH! Right. Just might be that we've thought of that eh?

Zack C - 2011/08/31 02:45:17 UTC

Why would you want to? Shouldn't releases be protected by weak links anyway?

And no response.

Just walks away from questions whose answers will reveal him to be the total moron he is and always has been and will be.

If you make the release really easy to engage something a lot heavier than anything it's got any business engaging people will try to fill it up with whatever they can.

[Steve Davy]

Sorry. Way too long an answer.

Not at all, I love to read and learn stuff. Thank you for taking the time to Thoroughly address my questions.

[Tad Eareckson]

Oops. When I was answering this:

What is/are the reason(s) for doing this?

question, I thought it was Antoine who had asked it. No harm done except:

...as you have illustrated here...

doesn't make much sense. Substitute "Antoine has" for "you have" and we're back on the rails.

Thanks for loving to read and learn stuff. Me too but, unfortunately, that only seems to be true of about one in a thousand hang glider people.

Anyway, I get to read and learn stuff too in the process of thoroughly answering questions... Patterns of disasters and coverups, how to identify and quickly and efficiently cut the enemy to ribbons (finding that spinnaker shackle on the Lookout tandem was like an extra Christmas), and how to express things more clearly for the good guys.