New Release?

[miguel]

From the Oz Report:



http://ozreport.com/16.19#1

[Tad Eareckson]

Just commenting briefly on the core mechanism here and the actuation system...

The way to do this job right is for the glider manufacturer to build it into the glider - but I'm not holding my breath.

Failing that...

Joe's done a very nice job on this thing. Very efficient design, simple, cheap, robust.

Bottom end is real good too.

I'm not a fan of cable but if you want something that can be quickly mounted onto a glider that's what you have to work with and Joe's got it well configured. I'd expect the function to be nearly as good as the rear brakes on a bicycle.

As far as safety/reliability is concerned...

I have no problem endorsing this or flying it myself and would predict its reliability to be one hundred percent. There's nothing else commercially available that I'd consider going up with.

I'll have some more comments in the "Releases" thread regarding this two point primary release assembly and the bridle/release system Antoine posted on The Davis Show.

[Tad Eareckson]

P.S. Joe's also the only tug pilot I know I'd feel comfortable towing behind 'cause he's the only driver I know knows what a weak link is.

[Zack C]

I'll have some more comments in the "Releases" thread regarding this two point primary release assembly and the bridle/release system Antoine posted on The Davis Show.

What, you didn't think that thread was long enough as it is? =)
Said comments start here:
http://www.kitestrings.org/post1326.html#p1326

I'm going to try to keep stuff on this release in this thread rather than spread out across others.

Joe was smart enough to take the most critical bend out of the equation.

(From here)
Not sure about that. If you're running a cable vertically down a downtube and pulling it horizontally on the basetube, it's going to have to bend.

To illustrate (password = 'red'):
http://vimeo.com/38334812

03-1304
http://c1.staticflickr.com/3/2938/13700558193_0e0946218e_o.png

One thing I noticed in making this video is that my hand moves pretty far just taking up slack in the cable before the cable pulls on the release. And when all the slack's out the bend is quite sharp. Joe says that a sharp bend is prevented by leaving at least 10 cm between the end of the housing and its attachment to the downtube, but I'm not following that...it seems like you're going to get a sharp bend no matter what you do, and the only reason it's not sharper is I'm pulling it across the angled portion of the speed bar.

Still works fine, but I'm wondering how it affects the release's performance. Also wondering if I should shorten the string attached to the cable so that I start with less slack and won't have to move my hand so far.

I thought maybe a better way to do this would be to run the cable on the outer side of the port downtube and run the lanyard around a VG bearing, but after looking at it I think the lanyard would contact the bottom of the downtube.

Zack

[Steve Davy]

Take a look at the throttle cable on some motorcycles. You will see that the cable itself can and does work smoothly when the flexible housing is terminated before the small diameter turn is introduced.

Edit: Tried posting a link but that's not working on my new and improved internet service. Google, Motorcycle throttle cable.

[deltaman]

it's going to have to bend.

virtually, it's clearly not an issue but.. as we are all quite obsessive here you just have to install a pulley on the corner downtube/basebar and you will pull the cable straight..

[Tad Eareckson]

What, you didn't think that thread was long enough as it is? =)

I figured that one three hundred post Kite Strings releases thread that goes somewhere is better than ten thirty post Jack and/or Davis Show releases threads that don't.

If you're running a cable vertically down a downtube and your pulling it horizontally on the basetube, it's going to have to bend.

Yeah, I meant the acute angle turn you hafta make if you follow the control frame corner and run the housing all the way to the basetube. Joe eliminated enough of it to make me happy.

One thing I noticed in making this video is that my hand moves pretty far just taking up slack in the cable before the cable pulls on the release.

So - like you're about to say - take up the slack before you need to.

- Engage the bridle via the weak link and have somebody pull forward to tighten the line between the quick link and the pin eye.

- Gradually slide your trigger hand inboard until your buddy tells you the barrel just starts to retract.

- Adjust things below - free cable end length, cable clamping position, and Monkey's Fist lanyard line length - so that it takes an inch - or whatever makes you happy - of inboard movement from normal hand position to blow you off.

- Don't go too hair trigger or you're gonna have a short flight.

...but I'm not following that...

If whatever's clamping the cable to the downtube is narrow enough to allow the housing above to bend outwards while the housing below is being pulled inwards the bend will get softened a little bit - otherwise I'm not seeing that extending the housing is doing anything and I think, even if it is, that ten centimeters is excessive. I'd be inclined to experiment with one centimeter - but this is Joe's baby and you're the one flying it.

...and the only reason it's not sharper is I'm pulling it across the angled portion of the speed bar.

And only a portion of your hand movement is being translated to bar movement.

Another biggie is that the housing isn't clamped tightly enough to the downtube and you're not just pulling cable - you're pulling housing. And that's knocking the crap out of your efficiency.

You can get a stainless steel hose clamp from the hardware store and form it to your faired tubing. It ain't elegant but it'll do the job.

I thought maybe a better way to do this would be to run the cable on the outer side of the port downtube and run the lanyard around a VG bearing, but after looking at it I think the lanyard would contact the bottom of the downtube.

- There is no VG bearing on that side - just a spacer. But it's easy enough to swap one in.

- A better way to do this is to drill a hole in the top of your downtube and run a lanyard inside down to a VG bearing and inboard to your hand. You can't beat the efficiency in terms of hand movement and force transmission.

You will see that the cable itself can and does work smoothly when the flexible housing is terminated before the small diameter turn is introduced.

I think Steve's right on this and I'm not worried about Joe's release Tabering on you. The release will work and - even if you hafta move your hand a bit - you don't hafta execute the USHGA "easy reach" and go looking for something while your glider's rolling upside down. You'll be able to maintain bar pressure which is almost certainly gonna be back. (This might be confusing to some of the students who've survived Ryan's Instant Hands Free Release - which requires forward pressure.)

...as we are all quite obsessive here you just have to install a pulley on the corner downtube/basebar and you will pull the cable straight..

That would be the best way to configure this release. BUT...

- This is supposed to be a slap-on release.

- We've already got it semipermanent because it needs a solid, fairly critical connection to the downtube.

- Now we're talking about a permanent and critical pulley installation so you can run a line lanyard around the bend and up to a clamped-on cable lanyard which runs the rest of the way up the outside of the downtube to the release mechanism.

- And MY stuff gets called Rube Goldberg.

- But nobody calls Wills Wing's VG system - which is pretty much the same thing - Rube Goldberg.

- And there are no threads - here or on the moronic Jack, Davis, and Bob Shows - discussing how to make VG systems more efficient, reliable, better.

- It's just so much easier and safer to do this job right once and forget about it.

- And we're having this discussion here 'cause the fuckin' glider manufactures haven't done their fuckin' jobs and spend their time stitching backup suspension and designing curved tips instead.

[Zack C]

Another biggie is that the housing isn't clamped tightly enough to the downtube and you're not just pulling cable - you're pulling housing.

What makes you say that? I don't think it's slipping.

You can get a stainless steel hose clamp from the hardware store and form it to your faired tubing.

I am using a hose clamp (as Joe suggested)...I just put the tape there to hold it while I clamped it and also to protect the downtube from any scratches from the clamp. The housing doesn't budge no matter how hard I pull it. If it was slipping, the length of cable from the end to the clamp would be increasing with use (it isn't).

A better way to do this is to drill a hole in the top of your downtube and run a lanyard inside down to a VG bearing and inboard to your hand.

Yeah, I was looking for a compromise.

Anyway, thanks for the input (all of you). I'm going to experiment some more and see if I can optimize things. I don't have a problem with the amount of force required to actuate the release, but I would like to minimize the distance my hand has to move.

Zack

[Tad Eareckson]

What makes you say that?

Looking down at it from the camera on the right downtube (?) it looks like it's getting pulled through.

I don't think it's slipping.

Then it probably isn't. I'm probably just seeing it getting pulled more horizontal. (Really looks like it's getting pulled through though.)

I'm going to experiment some more and see if I can optimize things.

Towing Aloft - 1998/01

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.

I don't think USHGA allows people to try to optimize things - just to die on releases that have been designed and extensively tested by the reputable manufacturers listed in Appendix IV of the excellent book, Towing Aloft, by Dennis Pagen and Bill Bryden who sell the excellent book, Towing Aloft, by Dennis Pagen and Bill Bryden.

[Steve Davy]

I don't have a problem with the amount of force required to actuate the release, but I would like to minimize the distance my hand has to move.

Looking at my Sport 2, I can't see any reason you could not run a lanyard down the outside of the down tube and around a pulley installed in the corner bracket. (Same place as VG pulley but opposite.)