Releases

[Tad Eareckson]

Comments on Joe's primary two point aerotow release and Antoine's primary bridle and secondary components in the photos at:

http://ozreport.com/forum/viewtopic.php?t=26440
"GETOFF" Primary Release - The Oz Report Forum

- The primary release core mechanism looks very solid. No recommendation for improvement other than using a longer heavier pin. And that pin's adequate and the best I've been able to find off the shelf.

- On the actuation end...

That's the best I can see doing with cable. There's a little slop in the system inherent in the arrangement. With a leechline/pulley actuation system you can minimize the slop and thus required hand movement and you can easily add a block and tackle arrangement at the top to boost the mechanical advantage. But no BFD.

- The Primary Bridle looks virtually identical to the last ones I made for Zack - right down to the color. I described the construction at:

http://www.kitestrings.org/post985.html#p985

Looks very nicely done.

From the photo it appears this has been done but I do want to emphasize that the material ends (at the bottom end of the bridle MUST be (lightly) stitched into place inside the splices to keep the bridle from wrecking itself on recoil after release.

(And I'm so very happy to see somebody else using a sailmaker's thimble.)

- The Primary Weak Link could be A LOT shorter. It's not problematically long but nobody ever had a problem with a weak link just long enough to adequately engage the release. (And it's more instructive to photograph it Fisherman's Knot up.)

- I'd prefer to not see the heat shrink Fairings on the Bridle Link when it's being used in a two point configuration. A Fairing WILL make the feed through the Thimble very rough, the Fairing will probably get chewed up going through, and there will probably be a hang-up issue in a slack line situation.

On the other hand...

With that primary release and bridle you'll probably never have to go to a secondary, even if you get a wrap the Bridle Link will very likely blow before you can even think of going to a secondary, the chances of needing to go to a secondary in a slack line situation are about as close to zero as you can get, and the Fairings protect the Strength Stitching from UV and abrasion. So, what the hell, that may be a better way of doing it anyway.

- It wouldn't hurt to extend the Barrel Releases forward from the shoulders a bit. Less force squeezing your shoulder straps together and it might make the Barrels easier to see and grab. But no BFD.

- In the photo the Barrel Releases are oriented such that the Pins are rotating inboard. If the Secondary / One Point Bridle apex angle is very acute you could have an interference/damage issue upon release. The chances of that are small and it's not a safety issue but set them so that the Pins rotate outboard to make the probability zero - there's absolutely no reason not to.
---
Just out of curiosity... What's your Primary Weak Link material and strength and what Bridle Link rating are you using?

[miguel]

Good informative post!

[Tad Eareckson]

Don't look so shocked. Outside of the gliders themselves, harnesses, and electronics it's not easy to find good stuff to write about in hang gliding.

[Steve Davy]

even if you get a wrap the Bridle Link will very likely blow...

Is the Bridle Link supposed to function as weak link?

[Tad Eareckson]

Yeah, the Bridle Link is a combination bridle / weak link. It's a flavor of what I dubbed the Shear Link.

Shear Links consist of two leechline elements stitched together with dental floss. The number of stitches determines the strength and up to about six hundred pounds direct load the predictability is pretty good.

You can check them out on my photo site:

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

There are a couple of higher resolution shots of a Bridle Link at the bottom of the composite photo:

Shear Links - 2

currently on the first page.
---
Edit - 2013/01/12

http://www.flickr.com/photos/aerotowrelease/8305364731/


http://www.flickr.com/photos/aerotowrelease/8306429930/

[Steve Davy]

All Bridle Links are shear links, but not all shear links are Bridle Links. Is that accurate?

Please post a link to Mousetraps, I've lost all my links until I get DSL working.

[Tad Eareckson]

Yeah. And a Bridle Link is actually the only glider end Shear Link that I like.

The Towline Shear Link is definitely gonna get dragged on the back end of an aero towline and probably at least a bit on a surface towline, it never got more field testing than a few flights, and I'd rather see a Tost sailplane weak link back there 'cause it doesn't care about dragging or dust.

The Ribbon Bridle was very nice but obscenely labor/time intensive.

The Bridle Links are easy, quick, cheap. Really happy with them.

Mousetraps at:

http://www.energykitesystems.net/Lift/hgh/TadEareckson/index.html

Good luck on your wire.

[Tad Eareckson]

http://ozreport.com/forum/viewtopic.php?t=26440
"GETOFF" Primary Release

Miller Stroud - 2012/01/27 22:10:43 UTC

Now this is personal preference and nothing more...

Sorry, when I'm going up in the air with something that can prevent or cause my death I need something a lot more solid than some idiot's personal preferences.

...but I hate strings and long cables when it comes to releases.

Yeah?
- How do you feel about strings and long cables when it comes to VG systems, reflex bridles, flaps, and spoilerons?
- Is anybody having problems with strings and long cables when it comes to VG systems, reflex bridles, flaps, and spoilerons?

For me it's too much exposure...

So run the string in your downtubes like every competition bladewing on the planet does for its VG system. Or would that level of engineering be way above your pay grade? (Rhetorical question.)

...and too much to constantly manage.

CONSTANTLY MANAGE?
- You pull it one time when you wanna blow tow.
- Isn't it:
-- total agony constantly managing your spoilerons?
-- partial agony occasionally managing your flaps?
- How good are you at managing a locking out glider with one hand while you're reaching for a release with the other?

http://groups.yahoo.com/group/skysailingtowing/message/6726
Weaklinks

Peter Birren - 2008/10/27 23:41:49 UTC

Imagine if you will, just coming off the cart and center punching a thermal which takes you instantly straight up while the tug is still on the ground. Know what happens? VERY high towline forces and an over-the-top lockout. You'll have both hands on the basetube pulling it well past your knees but the glider doesn't come down and still the weaklink doesn't break (.8G). So you pull whatever release you have but the one hand still on the basetube isn't enough to hold the nose down and you pop up and over into an unplanned semi-loop. Been there, done that... at maybe 200 feet agl.

Peter "Linknife" Birren seems to totally suck at it.

Dennis Pagen - 2005/01

By the time we gained about sixty feet I could no longer hold the glider centered - I was probably at a 20-degree bank - so I quickly released before the lockout to the side progressed. The glider instantly whipped to the side in a wingover maneuver.

Dennis "Towing Aloft" Pagen isn't a whole helluva lot better.

I'd rather do a lot of managing of stuff when the shit's NOT hitting the fan so I have a minimum amount of managing to do when it IS. But, hell, I guess this is just a matter of personal preference and nothing more.

I also do not like the actual release "out of reach" in the event hell breaks loose.

Yeah. Say you're locking and your two point release is jammed AND your port spoileron is stuck. You'd hafta stand up in the control frame to pull the release open, unhook, and climb out on the left wing to free up the spoileron. That could be a real bitch under three hundred feet. That's why Joe designed a release that actually works - so he didn't hafta plagiarize Matt's owner's manual and spend thirty pages telling his victims all about how to use backup releases, weak links, and hook knives to keep themselves from getting killed in emergencies which finished playing themselves out ten seconds ago.

Now I would like to see that release mounted on a handle or very short (less than 18") piece of cable directly in front of me.

Yeah, well...

http://www.ushawks.org/forum/viewtopic.php?f=2&t=607
Understanding Tow Releases

Peter Birren - 2011/08/29 18:40:45 UTC

Fuckin' coward...

I'm a fuckin' coward so...

British Hang Gliding and Paragliding Association Technical Manual - 2003/04

On tow the Pilot in Command must have his hand actually on the release at all times. 'Near' the release is not close enough! When you have two hands completely full of locked-out glider, taking one off to go looking for the release guarantees that your situation is going to get worse before it gets better.

...I don't want the fuckin' release mounted on a handle or very short piece of cable directly in front of me. I want the fuckin' release actually in my hand at all times.

...ignorant coward.

I'm also an ignorant coward so I also want that hand...

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

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

...on the bar at all times 'cause I just never could figure out how to fly my glider on tow with just one.

Of course I'm a Pro Tow pilot...

OF COURSE you are! FAR superior to the rest of us slow, stupid, incompetent, two hand flying clods.

...and have no need for a keel mounted release.

No need WHATSOEVER. Who could POSSIBLY imagine being in a situation on tow in which you'd need every inch of pitch range for which the glider was certified?

I've included a pic of Peter Biren's linknife release that I've incoporated into a short compact system.

Oh good! Short and compact! Have you talked to Davis? He seems to be into long, thin, and easily stowed. Oh well, this is all about personal preferences and nothing more anyway.

The pic is a double release but can be made up as a single also. And the best part? There are no moving parts, cables, or strings to break, kink, or malfunction.

01. Perish the thought that we should have a MOVING PART on an AIRCRAFT!!!

02. The Linknife HAS a moving part - the O-ring.

03. The Linknife IS a moving part. It needs to move in relation to the string it's trying to cut. And it's been demonstrated in the field that a little wheat stubble can stop it from moving.

04. And to get the Linknife to move you need to move your hand - from what it needs to be doing, which is trying to control the glider, possibly when all hell is breaking loose - to the other thing it needs to be doing, which is pulling the cable, possibly when all hell is breaking loose. And a lot of people have died on hang glider tows because they had to pick one when both were necessary for survival (you moron).

05. And in those not infrequent occasions neither short and compact nor long and thin count for shit.

06. No. There aren't any strings to break. Just one that you need to CUT and REPLACE every tow.

07. Exactly what is it in the illustrated system that you expect to not move, break, kink, or malfunction and how many idiot things are you figuring on doing to get something to not move, break, kink, or malfunction?

08. What is it you do to your glider, harness, and parachute to get THEIR components to not move, break, kink, or malfunction?

5:00
http://www.youtube.com/watch?v=kcKebsmnVUk


09. Never mind.

10. Are we seeing any release systems that were actually DESIGNED failing unpredictably because they didn't move or broke, kinked, or malfunctioned?

11. That's the BEST PART?! Wow. It must be really great to be that easily pleased with a piece of mission critical aviation equipment. I could've so easily saved myself zillions of hours of R&D.

[Tad Eareckson]

Zack C - 2012/01/28 2:05:35 UTC

The Get Off release is just a remote straight-pin barrel. For towing pilot-only ('pro tow'), the simpler hands-on straight pin barrel secondary releases in Antoine's original images are more than sufficient.

No no no no! The barrel release has moving parts! The barrel has to move backwards, the pin has to rotate, and the Bridle Link has to feed through the tow ring. Any one of those actions could fail in any one of a thousand totally unforeseeable ways. Why take a chance on moving something when you can just cut it in half?

I don't like cables either, but I also don't like having to take a hand off the bar to release, so I put up with them.

If I could just get you to drill that hole you'd be on your be well on your way to the best of all worlds. But, what the hell, I'm pretty sure that you won't have any problem with Joe's.

[deltaman]

Tad, I recognize you. You didn't miss any trouble on my pics. I did it quickly and took barrels and bridle link I use in 1 point and forgot to remove heatshrinks and don't put the extension here



I stitched the 2 eyes of V-bridle (not sure you said the opposite)

As a wl I'm confortable to use and recommend 1.4G with a release you can actuate without letting go 1 hand..
And at the bottom side 1.2 times stronger..

I did the 4 strings and will try to publish it too, in action..