New Release?

[Zack C]

So I took out the slack in the cable/lanyard and I actually think it made things worse. My hand meets the spring's resistance immediately instead of having time to accelerate first. Consequently, I found myself applying insufficient force to actuate it. Password = 'red':
http://vimeo.com/39629167


I've always thought the 11 lbs required to compress the spring seemed a bit much on the ground, but it previously wasn't an issue in flight. Joe could use a weaker spring, but I'd rather not be lulled into thinking only a light pull is required when tensions are high...

Zack

[Tad Eareckson]

I've always thought the 11 lbs required to compress the spring seemed a bit much on the ground.

It is. It's WAY too freakin' much.

http://www.flickr.com/photos/aerotowrelease/8306258400/


That pathetic negligible little loop of sixteenth inch bungee is all you need to do the job. All it needs to do is keep the barrel from falling back before the system is loaded. You start adding to that you're just degrading the performance of your release for no reason. You should be talking in terms of ounces (one or two) - not pounds.

...but I'd rather not be lulled into thinking only a light pull is required when tensions are high...

You bloody well SHOULD be lulled into thinking only a light pull is required when tensions are high. You'll have enough things to worry about when the shit is seriously hitting the fan without needing to add a major muscle requirement - or, for that matter, all that hand movement you're having to do - to the brew.

If a ten year old kid on a bike is doing thirty-five miles an hour down a hill when a car backs out of a driveway you don't hear him later moaning in the hospital that he couldn't stop fast enough because he simply couldn't deliver the required muscle to the brake levers without using so much hand movement that he'd have lost directional control and slammed into a lamp post. (He may still end up in the hospital but it won't be because he couldn't instantly and effortlessly lock up the wheels with the brakes without the least steering control compromise (other than that caused by the locked up wheels).)

And the engineering to do that job is a few hundred times more demanding to do than the one we need to. There's absolutely no fuckin' way I could produce a safe bicycle brake system on the kitchen table. But - with a few off the shelf components - I can punch out a two point aerotow release system which will blow 650 pounds towline with a twelve pound pull and an inch of hand movement. That's two Gs for a pretty heavy solo glider and something that nobody's ever gonna see anyway.

Doug Hildreth - 1991/06

Pilot with some tow experience was towing on a new glider which was a little small for him. Good launch, but at about fifty feet the glider nosed up, stalled, and the pilot released by letting go of the basetube with right hand. Glider did a wingover to the left and crashed into a field next to the tow road. Amazingly, there were minimal injuries.

Comment: This scenario has been reported numerous times. Obviously, the primary problem is the lack of pilot skill and experience in avoiding low-level, post-launch, nose-high stalls. The emphasis by countless reporters that the pilot lets go of the glider with his right hand to activate the release seems to indicate that we need a better hands-on way to release.

I know, I know, "If they would just do it right. Our current system is really okay." I'm just telling you what's going on in the real world. They are not doing it right and it's up to us to fix the problem. Think about it.

That was over TWENTY FUCKIN' YEARS AGO. And that was the responsibility of the glider manufacturers to do something about. And they didn't do SHIT.

So Steve Kinsley and I did their jobs for them and handed out the engineering for free on a silver platter. And Wills Wing dealerships responded by ignoring, rejecting, suppressing, and pissing all over it. And they united against Yours Truly when he started rocking the boat and blacklisted him from sea to shining sea. And ditto with USHGA - which is just an association of Wills Wing dealerships.

And they've gotten a lot of people crashed, hurt, killed and they've used their fuckin' lawyer to suppress the reports and analyses that decent people like Doug Hildreth used to do.

http://ozreport.com/forum/viewtopic.php?t=25321
Stop the Stupids at the USHPA BOD meeting

Mark G. Forbes - 2011/09/29 02:26:23 UTC

We can establish rules which we think will improve pilot safety, but our attorney is right. USHPA is not in the business of keeping pilots "safe" and it can't be. Stepping into that morass is a recipe for extinction of our association. I wish it were not so, but it is. We don't sell equipment, we don't offer instruction, and we don't assure pilots that they'll be safe.

And now it's FINALLY blowing up in their faces 'cause they haven't been able to bury this kinda data from their insurance company and all the sudden they're EXTREMELY interested in keeping pilots safe - about thirty years too fuckin' late.

So Zack, here you are on 2012/03/31 - on your fourth slap-on two point aerotow release still having problems trying to pry it open at straight and level regularly scheduled wave-off.

I hope you recognize who your enemies are and how much they've been fucking you over...

Zack C - 2010/12/13 04:58:15 UTC

I had a very different mindset too back then and trusted the people that made my equipment. Since then I've realized (largely due to this discussion) that while I can certainly consider the advice of others, I can't trust anyone in this sport but myself (and maybe the people at Wills Wing).

...even if they're people you really like and have always admired. That's a tough one to do, but that's where the root of the problem is. Just follow the money.

[Tad Eareckson]

P.S.

Zack C - 2011/08/26 00:20:56 UTC

It always amazes to hear know it all pilots...
...
Some weekend warrior isn't about to inform me about jack sh*t when it comes to towing.

Wow. The irony. The arrogance. And people call Tad arrogant...I can see why you have so much contempt for this guy, Tad.

So most of this was just the same old story of debunking Tad's lunacy... again .

I have yet to see anyone debunk Tad's 'lunacy'...

That's a Wills Wing representative you're talking to, Zack. That's the guy Steve, Mike, and Rob are backing - not me. And it's his equipment, procedures, and opinions and "theories" that rule the runways and skies - not mine, Steve Kinsley's, Doug Hildreth's, or Sir Isaac's.

[Zack C]

You bloody well SHOULD be lulled into thinking only a light pull is required when tensions are high.

'Light' is subjective. For a 200 lb weak link and a L/A of 15 (as Antoine reported for this release), we'll have a maximum pull of 13.3 lbs, which is hardly what I would call light.

Here's my thinking, which may not be correct...I haven't done enough experimentation to verify this. The required actuation force of the release is a linear function of the load applied - but only past the minimum, which is present even when there's no load. For this release, the minimum is determined primarily by the spring and is about 11 lbs. Once the load is sufficient to require an actuation force greater than the minimum, a lower minimum wouldn't make a significant difference.

So, let's assume it will take 13.3 lbs to release a 200 lb load. An 85 lb load would take 11 lbs since that's the minimum. If a lighter spring was used bringing the minimum to, say, 1 lb, an 85 lb load would take 5.7 lbs to release, but the 200 lb load would still require 13.3 lbs. Again, this may not be correct. I chose 85 because I tested Joe's release to that load (it took 11 lbs, same as with no load) and I suspect it's about the most the release would see under normal in-flight conditions.

At any rate, the reason I'm not sure if a lighter spring is a good idea is that if I'm accustomed to releasing with 5.7 lbs, I may deliver only 5.7 lbs when the tension is 200 lbs and therefore fail to actuate the release.

When I first got the release I tested it before mounting it and thought the 11 lbs with no load was excessive. I checked with Joe to make sure that was normal and he said it was, and that he could have used a lighter spring but didn't want a hair trigger. He said that under normal in-flight load the actuation force will feel the same on the ground as in the air, and subjectively this seems to be the case.

You'll have enough things to worry about when the shit is seriously hitting the fan without needing to add a major muscle requirement - or, for that matter, all that hand movement you're having to do - to the brew.

To me, 13.3 lbs is a lot...I find it very hard to keep a hand on the bar while delivering that kind of force.

Zack

[Steve Davy]

Zack,

Why don't you install the release designed and tested by Tad?

[Tad Eareckson]

'Light' is subjective.

Yeah, but in the release performance specifications in Towing Aloft, the "suggested reference", which everybody happily ignores, the max allowable pull is 25 pounds - and that's not terribly unreasonable. Although we can do a lot better.

For a 200 lb weak link...

348 pounds towline.

...which is hardly what I would call light.

That's a house cat. If the shit's hitting the fan you'll never feel it. The kid on the bike is squeezing twice that with each hand.

The required actuation force of the release is a linear function of the load applied...

Yes.

I chose 85 because I tested Joe's release to that load (it took 11 lbs, same as with no load)...

You put the base line under load and took the slop out of it. That moved the pin forward. That means you didn't hafta compress the spring as much for the barrel to clear the end of the pin. That's why your graph is flatlining up to that point.

...and I suspect it's about the most the release would see under normal in-flight conditions.

Close enough.

At any rate, the reason I'm not sure if a lighter spring is a good idea is that if I'm accustomed to releasing with 5.7 lbs, I may deliver only 5.7 lbs when the tension is 200 lbs and therefore fail to actuate the release.

Keep sliding your hand inboard until it starts getting quiet and the tug starts getting smaller. Worry about how many pounds it took later.

I checked with Joe to make sure that was normal and he said it was, and that he could have used a lighter spring but didn't want a hair trigger.

Big mistake. What makes these things hair trigger is lanyard (cable) play - the spring should have absolutely nothing to do with the issue.

He said that under normal in-flight load the actuation force will feel the same on the ground as in the air, and subjectively this seems to be the case.

Minus any adrenaline factor - yes.

To me, 13.3 lbs is a lot...I find it very hard to keep a hand on the bar while delivering that kind of force.

- You're probably just gonna be needing to hold back pressure on the bar to keep from rolling on your ear.

Why don't you install the release designed and tested by Tad?

- If you wanna get rid of the cable and replace it with leechline I can boost the mechanical advantage to anything you want.

[Zack C]

You put the base line under load and took the slop out of it. That moved the pin forward. That means you didn't hafta compress the spring as much for the barrel to clear the end of the pin.

I'm not sure I'm following you. But when I tested with 'no' load, I tested with literally no load as well as with a minimal load...just enough to tension it. I actually have that on video (red):
http://vimeo.com/30471278

Keep sliding your hand inboard until it starts getting quiet and the tug starts getting smaller. Worry about how many pounds it took later.

The easiest way to deliver a lot of force is with a jab (how Lookout recommends you actuate their releases). If you don't deliver enough force with one jab, you're going to have to do two...or more (as I've illustrated in many videos, including the second release in the video in my previous post).

You're probably just gonna be needing to hold back pressure on the bar to keep from rolling on your ear.

If that's all you need, I think a basetube-mounted brake handle would be fine (assuming it worked...).

I'm not clear on what your problem with the 11 lb spring is, Tad. You're OK with the L/A of this release. Are you saying that it could be better with a lighter spring? Or is your issue that it requires too much force at lower loads? At any rate, I don't think a lighter spring would address the difficulty I had under higher loads...only normal loads.

I'm going to go back to having a longer pull...it worked better that way.

Why don't you install the release designed and tested by Tad?

The hole drilling is a bit critical. You punch the spot and drill through with the smallest bit available. Then you go with successive sizes up enlarging and angling to arrive at a final eighth inch hole slanted upwards and outwards.

http://www.flickr.com/photos/aerotowrelease/8306275994/


The lanyard feeds out through an eighth inch OD length of nylon tubing - friction fit, low internal friction, eliminates abrasion issues.

1. It would require surgery.

With my Remote Barrel unboosted you can blow 130 with an eight pound pull.

2. Unboosted, the performance wouldn't be significantly better. Boosting will require more surgery (not sure how much...I'll let Tad speak to that).

Zack

[Zack C]

Unboosted, the performance wouldn't be significantly better.

Clarification...the L/A of Tad's release unboosted is comparable to that of Joe's. Its low load performance is of course better, but it's the upper end I'm most concerned about.

Zack

[Tad Eareckson]

I'm not sure I'm following you.

- Joe's using red Spectra line to which runs between the quick link and pin eye through the barrel mechanism.

- Spectra is essentially - for the purpose of this exercise - zero stretch AFTER it's loaded up under normal tow tension.

- But it's gonna elongate a bit as it's loaded up from zero tension - at which point it's short and fat.

- The barrel release performance - minus the spring - is absolutely linear. If the load to actuation ratio is fifteen to one you'll need to pull an extra pound for every fifteen of load you add.

- My keel mounted barrel release system:

http://www.flickr.com/photos/aerotowrelease/8306258400/


is under tension all the time - whether or not the bridle is connected to it. It's tensioned to the nose primarily because it needs to be to be functional in a slack line situation. So there's no (significant) slop to be taken out of the system as the tow tension loads things up.

- Joe's assembly could easily be rigged the same way.

- If it were rigged that way fifteen pounds of direct loading would require a fixed eleven pounds of spring compression plus another pound to overcome the friction of the mechanism.

- But it isn't, so at low tension while the Spectra is still short and fat you hafta pull the barrel farther back - and compress the spring more - to clear the pin.

- So for some of that low range increasing the load could DECREASE the required pull.

The easiest way to deliver a lot of force is with a jab (how Lookout recommends you actuate their releases).

They also advise that...

There is no product liability insurance covering this gear and we do not warrant this gear as suitable for towing anything.

...their "releases" aren't suitable for towing anything and that...

The new GT aerotow release, new as of July 11th 2009, is designed to be used with a V bridle and a 130-pound green stripe Dacron tournament fishing line weak link. At this time it is not recommended to use this release with a higher value weak link.

...at this time it is not recommended to use this release with a weak link of a higher value than 130 pound green stripe Dacron tournament fishing line. And the value of a 130 pound green stripe Dacron tournament fishing line weak link is comparable to the combined value of parachute in a container with no pins and worn out velcro and a hang check in the setup area twenty minutes before launch.

If you don't deliver enough force with one jab, you're going to have to do two...

If you live that long.

...including the second release in the video in my previous post).

I'm less concerned with the spring issue in Joe's release than I am with Matt's crap. At least I know that the spring issue CAN be overcome fairly quickly and easily.

Ralph Sickinger - 2000/08/28 18:18:20 UTC

Under sled conditions, I decided to borrow Brian Vant-Hull's glider instead of setting up my own, since we both fly the same type of glider. Brian's release is a different style, but I tested it twice during preflight to make sure I was familiar with it. After towing to altitude, Sunny waved me off; I pulled on the release (hard), but nothing happened! 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; Sunny had no choice but to gun the engine in attempt to regain flying speed, but this resulted in a sudden and severe pull on the harness and glider; I was only able to pull on the release again, while simultaneously praying for the weak link to break. The release finally opened, and I was free of the tug.

Brian Vant-Hull - 2000/08/28 22:49:13 UTC

I purchased my release (the one Ralph used) at Lookout Mountain over a year ago, but never had any problems until the Ridgely Fly-In, where the same thing happened. I pulled three or four times on the release, then finally went to the secondary, by which time I was high above the tug and Sunny (is there a connection here?) was frantically waving me off.

No way in hell I'd go up on that piece o' shit. And that piece o' shit is way more reliable than Matt's new and improved piece o' shit.

If that's all you need, I think a basetube-mounted brake handle would be fine (assuming it worked...).

- Yeah, but given their record on the downtube where the cable bending is minimized...

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.

...no way in hell would I do that.

- IF you had a reliable basetube mounted brake lever system it would be safer to trigger than my own system. You could white knuckle clamp your hand to the basetube and blow tow with an index finger.

- But I still wouldn't use it 'cause I can blow mine by just twisting my grip, I wouldn't put all that crap in the airflow, and the lever gives you something you can use to snag a bridle.

Are you saying that it could be better with a lighter spring?

Yeah. It could be 10.9 pounds better.

Or is your issue that it requires too much force at lower loads?

I'm not real worried about it but if something can EASILY be made better it should be made better.

At any rate, I don't think a lighter spring would address the difficulty I had under higher loads...only normal loads.

It would address over ten pounds of it.

I'm going to go back to having a longer pull...it worked better that way.

You're adjusting your procedure to compensate for an engineering problem rather than fixing the engineering problem.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=3600
Weak link question

Lauren Tjaden - 2008/11/20 22:50:53 UTC

I practiced releasing using varied types of release under load (on the ground) at Highland this year, and found it very educational. When pro-towing the method the pilot uses to release can be very important (something I'd never realized, since I've -- knock on wood - never locked out while pro-towing). I found that the only way to release under strong loads (with either curved or straight pin releases) was to grab the TOP of the barrel instead of just grasping around its sides.

(Lauren wasn't using a sane straight pin barrel like mine - she was using one of those idiot short fat barrel / webbing pieces of crap like Steve Wendt punches out, a Bailey release with a straight pin swapped in.)

It would require surgery.

- I performed no surgery in my initial designs. I mounted a spinnaker shackle at the keel, lashed some guide rings to the port downtube and ran a 205 leechline lanyard down to the basetube. And I NEVER had a problem blowing it - or any of my later evolutionary stages.

Unboosted, the performance wouldn't be significantly better.

Negligible spring resistance, no cable resistance, no cable flex at the bottom, minimal required hand motion.

- By delaying or not doing surgery on your glider you're increasing the probability of someone needing to do surgery on you. You're not increasing it much - but you ARE increasing it.

Boosting will require more surgery (not sure how much...I'll let Tad speak to that).

Nope. Once you've got a basic installation - with or without surgery - it's a very simple matter to start adding pulleys at the top.

[Zack C]

Are you saying that it could be better with a lighter spring?

Yeah. It could be 10.9 pounds better.

By 'it' I meant the L/A. My thinking is that above a load of 165 lbs a lighter spring would not make a difference. Do you agree?

You're adjusting your procedure to compensate for an engineering problem rather than fixing the engineering problem.

I'm adjusting my procedure so that I can release easily when I have a, say, 200 lb load. I'd want to do this even if it wasn't necessary for normal tensions (i.e., if I used a lighter spring).

...minimal required hand motion.

Even if boosted?

Once you've got a basic installation - with or without surgery - it's a very simple matter to start adding pulleys at the top.

If that is the case, your release just got a whole lot more appealing to me. I was going by your picture here:

Block and Tackle by tadercksn, on Flickr

It looks like a pulley has to be screwed into the downtube.

Zack