...on the weak link at the end of the towline just before the over/under split.
There will be a lanyard running back from the Linknife along the over-the-basetube line to back where you can reach it.
Put a ball with a hole through it on the over-the-basetube line and tie the lanyard to it.
Do whatever you need to to make it a tight fit to lessen the chances of accidentally cutting yourself loose.
Normally you'll climb until the over-the-basetube line starts interfering and you blow it - along with the Linknife emergency release components - off and clear using the left barrel. At this point you're high and probably out of danger and one (right) barrel pull from being off tow anyway.
When you top out pull the right barrel and the towline, over-and-under-the-basetube lines, and Linknife emergency release assembly get reeled back in and you fly away with your two stage barrel release assembly.
In a low level emergency... Pull the ball which pulls the lanyard which pulls the Linknife which cuts the weak link which dumps the towline and leaves you with everything else.
I don't remember what do you advice as a surface towing takeoff.
If you:
- can aerotow - don't
- can't aerotow then platform launch off of the back of a truck or a trailer and use a three-string, a Koch used as a one stage, or a pair of barrels on your hips
- don't have a:
-- platform launch rig then launch off a dolly using a Koch two stage or that two stage barrel system with the Linknife amendment
-- dolly then use the same equipment as described just above, use a double lift and tug as your "clear to launch" signal, and don't do anything stupid until you get to two hundred feet
I thought: 1 point under the basebar with dolly...
Looks like it's working OK for those guys but it also looks like they're starting out on a short towline so the angle is increasing rapidly and the bridle is only briefly in contact with the basetube.
Maybe they're using a truck or boat with a payout winch so they can let out line and get them high after the launch and initial climb?
...but which release(s) and where ?...
They're using stupid Bailey Releases in close to their harness tow loops.
Tad Eareckson wrote:
1. There's going to be a Linknife...
Took time to understand ! now it's ok. Thanks.
Tad Eareckson wrote:3. If you don't have a platform launch rig then launch off a dolly using a Koch two stage or that two stage barrel system with the Linknife amendment.
I thought: 1 point under the basebar with dolly...
Looks like it's working OK for those guys but it also looks like they're starting out on a short towline so the angle is increasing rapidly and the bridle is only briefly in contact with the basetube.
What is the pb by towing like these guys rather than 3. ? 1 step (under) seems to me easier: You can leave the ground without having to let go of one hand as you have to in 2 steps mode..
Aside from the stupid Bailey Releases I don't have any big problems with the way those guys are towing. The bridle is only pulling forward on the basetube briefly, it doesn't seem to be causing trouble for anyone, and I'd opt for a pair of barrels over a Koch in those circumstances too.
But the Koch WOULD be safer - no pull on / interference with the basetube at all and easier to blow in an emergency.
Yes, for the Koch you always have to take a hand off to climb to a high tow angle but the timing isn't critical - so you can always do it at your convenience when everything's under control.
Somehow missed seeing your e-mail message confirming the receipt of your bridles till last evening. Major sigh of relief.
I was a bit late getting them off and forgot about Veteran's Day. But they did get to the post office before noon two Saturdays ago and I was hoping you'd have had them by at least mid week and was getting worried.
I figured out how to do these a little better since punching your first one out and am including the construction steps here so if I get hit by a truck later today the technology won't be lost.
---
Material is Samson Amsteel Blue - 1/8 inch diameter.
Target finished length is ten feet (a somewhat arbitrary figure) and this procedure brings it very close.
Finished diameter is 1/4 inch.
Eye splices at both ends are effected to snugly fit an RF2180 Ronstan Sailmaker's Thimble (even though the thimble is only installed in the bottom eye).
The stitching is:
- nylon dental floss
- designed to be removable so it's spaced generously and there's no overlap
- not structural - it's only necessary to keep the splicing from shifting
It's critical that the ends - which meet internally a foot from the bottom end - be secured with stitching. Otherwise when a bridle end is released under tension the bridle will recoil, the ends will go berserk inside the bridle, the bridle will become unusable, and the line will need to be completely unspliced and redone.
A ten foot bridle eats up about 21 feet 07 inches of material but you'll need a little excess to make a precise cut at the end of the construction at a point which can't be precisely predicted.
Using water soluble ink, mark a point 9 feet from an end of the line and fold the line back on itself (180 degrees) at that point.
Place a thimble at the fold and mark the standing end (long run of the line) for a snug splice around it.
Insert the nine foot end in a fid.
Run the fid in through the mark and, by bunching up the outside material that's passed back beyond the fid, work the end through to well beyond the point at which that length will fall when pulled taut and exit.
Install the thimble in the eye and make the splice snug around the thimble by pulling the protruded end of the line.
Draw the bridle smooth near its completed end and run several stitches at the end of the overlap to lock the eye size.
Remove the:
- fid and smooth the bridle until the free end is drawn back inside to as close as possible to what will be its finished position.
- thimble, tie a Figure 8 Loop Knot beyond the overlap, and load the bridle to at least two hundred pounds to establish the inside end in its proper position
Use a stitching run of about a foot to lock the end of the overlap.
Further stitch the finished end and lock the eye splice.
Untie the knot, measure 10 feet 2 inches from the finished end and mark.
Form an eye splice centered on the mark as described above.
Exit the outer material as close as possible to the end of the established overlap with the goal of butting the ends together.
Lock the
- new eye size as before and again load the bridle to two hundred pounds
- bottom end with stitching from near the exit back to the eye
Draw the end out slightly and, using wire cutters, cut the line square with the goal of butting the ends together as closely as possible without overlap and draw/work the end back inside.
Cut a one inch length of quarter inch diameter heat shrinkable tubing, slide it onto the bottom (last formed) end of the bridle to just above the eye (and NOT at the internal junction where it will end up), and immerse in a small glass of water brought to the boiling point in the microwave.
Just, as I've said before, that I recommend that you be a little more generous with respect to the Trigger length - upon which all the loop lengths are based - so that you're sure to have reasonably comfortable freedom of head movement for the short time it takes to get to the two hundred feet or whatever it is you feel like calling a non critical altitude. (And there's a formula in the text for measurements for whatever Trigger length you want.)
Otherwise... It's a pretty simple design, everything's identical to what's described and appears in the photos, and I'm VERY happy with the mechanism. It's a nice feeling to have it available launching two point and you've gotta be a bit nuts to regularly tow one point without it or some other hands free option.
Great, now how about a picture of the same system after sitting cocked for a couple years in a salty, sandy environment... Everything works great in the lab in static conditions. The real world tends to be harsher though...
Springs stretch, metal rusts in place, etc.
Yeah Stuart, you should always leave critical glider towing equipment sitting cocked for a couple years in salty, sandy environments and never preflight, test, or maintain it. 'Cause...
Mike Bomstad
Everyone who lives dies, yet not everyone who dies, has lived.
We take these risks not to escape life, but to prevent life escaping us.
...flying just isn't any fun unless we do as much stupid shit as humanly possible to make the outcome as dangerously unpredictable as humanly possible.
And I guess if:
- you're not flying in salty, sandy environments you're not really flying anyway.
- it didn't work in a life and death situation it would be like all the other tow rigs that don't have them. 'Cept it would actually be worse 'cause everybody would be expecting the pilot to live. So it's probably just better to not install these things 'cause we don't wanna take a chance that people might get nasty surprises after getting their hopes up.
I mean it's not like our parachutes which work with one hundred percent reliability after sitting out for a couple years in a salty, sandy environments.
Besides...
Stuart Caruk - TowMeUp.com
Most reliable sources believe that a weaklink should be sized so that it breaks at 75% to 100% of the inflight load.
...we HAVE weak links, sized to three quarters to one G in accordance with what most reliable sources believe, and, as most reliable sources will assure you, they'll always blow before you can get into too much trouble.
Dan Hartowicz - 2012/01/22 02:21:14 UTC
Well there is stainless steel, oil coatings, but I agree that different environments demand different preparation for lasting dependability.
What? Kinda like the air into which we go after all that preparation that Stuart doesn't think we should be doing?
Gregg Ludwig - 2012/01/22 06:53:28 UTC
My opinion is that such a device as pictured is too dangerous and perhaps presents more safety issues than it intends to resolve. It is too easy to have a helper chop his fingers off.
Please... no guillotines!
Your OPINION. Oh goodie!
Yeah, maybe we should take tail rotors off of choppers while we're at it. They move a helluva lot faster and are a helluva lot harder to see. (I have a cousin whose kid watched an army captain walk into one of those.)
It's a little over a half an old lawnmower blade.
- It's only sharp over the width of the red mounting. (And it only needs to be sharp over the width of the opening.)
- And it's painted in a scheme designed to get people's attention and put them on guard.
- And the only way an idiot helper can get fingers chopped off is to insert them through the opening AND have an operator trigger the actuator.
I met Barry Gordon and Linda Tracy at Lookout Mountain during 1977(?). They were traveling the mainland in a VW bus and were just the nicest and most congenial folks. I felt really bad for Linda who'd recently had a wire assistant hang on too long then fall to his death at the big cliffs on Oahu.
Maybe we should worry more about getting wire crew safetied than winch crew getting fingers chopped off?
What's the bigger risk with the bigger consequences? Somebody getting his fingers chopped of by the guillotine or somebody getting his neck broken 'cause he's locked out and can't abort the tow?
Accident Review Committee Chairmen have been screaming for observers with machetes and guillotines for decades.
So you got any better ideas?
This is a dangerous game which cripples and kills a lot of participants and you need people who follow procedures and know what the fuck they're doing on BOTH ends of the string.
I note that at least the guy in the video isn't stupid enough to insert his fingers through the opening along with the spectra he's feeding. As a matter of fact, he appears downright skittish about the whole procedure. I think he'll be able to maintain a good typing speed for a very long time.
What's your OPINION of universal 130 pound Greenspot Industry Standard aerotow weak links?
I witnessed the one at Lookout. It was pretty ugly. Low angle of attack, too much speed and flew off the cart like a rocket until the weak link broke, she stalled and it turned back towards the ground.
Any REMOTE POSSIBILITY that THEY'RE dangerous and PERHAPS present more safety issues than they intend to resolve? I don't seem to recall you - as USHGA Towing Committee Chairman - being as quite as outspoken warning of the "potential" hazards of those things - or doing shit to get a minimum rating into the SOPs.
Sweeeet!!!! Looks good to me.
I like the bent gate bar, as Marc suggested that should make release force many times less than tow force, if not nearly independant of tow line force.
Nicely done Lookout! Elegant solution!
As in most cases, the simplest designs work best.
Asshole.
Good job, Guillotine Guys. That's close to the concept I was recommending for the tug release Antoine was talking about.
I'm surprised to see you endorse the guillotine concept. After all, you once said
There is no way in hell I would tow with some bozo with a knife poised over my lifeline. I'm the fucking pilot in command and I don't want some asshole a football field away making my decisions for me.
Under what circumstances do you think it's acceptable for a winch operator cut the line?
Ya gotta register. Tell him Tad sent you - that'll help expedite the process.
I DON'T want some bozo with a knife poised over MY lifeline. But it's probably not a bad idea to have some bozo with a knife poised over SOMEBODY ELSE'S lifeline.
The less of a bozo the person on the other end of the string is, the less uncomfortable I am with the idea of him having a knife.
What the hell, he has a throttle with which he can save or kill me anyway.
At some point of reduced bozoness the person with the knife starts becoming more of a potential asset than a threat.
I think I like these guys. I have a soft spot in my heart for ANYBODY who's put a new idea into the field - even a bad idea like a hook-in alarm. And this is a very nicely engineered piece of hardware. I don't think these guys are bozos.
I have a 1.5 G weak link on my glider. In one set of circumstances it could save my glider and thus myself. In another it could almost instantly kill both of us. I view a non bozo with a knife as a potentially / hopefully smarter version of the weak link.
On aero I'm one hundred percent confident that I can blow hands-on as fast as I can react, way faster than the driver can react, and way way faster than the weak link will kick in. The tug's release is for his safety only.
The engineering to blow surface hands-on is a lot more complex and difficult and less straightforward, I haven't done it, and nobody else is likely to. With just a Koch two stage a guillotine could prove extremely useful. And even with the solenoid powered emergency system I'm envisioning I wouldn't mind a Plan C in the configuration.
Shit happens - especially when you have people involved in anything.
It's better to have an option that you never use in a hundred thousand flights than to need an option once in a hundred thousand flights and not have it. I like options and redundancy.
Joe Street, a Canadian Pilot, makes this release. Contact: <racingtheclouds>.
I purchased and tested first the LMFP and then the SteevReleases and I can say this one is by far the best. I changed releases several times and searched for something more reliable because I encountered difficulties releasing at high loading, as other pilots have reported on the web. You can actuate this release at no load and at high load for much less effort (direct load/actuation effort=15+). Don't know why but, to date, it is the cheapest too!
It's cheapest because it's designed to do the job - rather than being slapped together to make it look like what most glider divers expect a tow release to look like.
Jim Gaar - 2012/01/26 06:07:58 UTC
A new mouse trap?
Funny you should use that particular term.
I assume that's the "Pro Tow" and the COM models shown?
There's no such thing as "pro tow" or center of mass models.
The slightly different "Pro Tow double barrel" looks good but nothing new there.
Slightly different from what? The tried and true Industry Standard Bailey bent pin job?
SLIGHTLY different? Like over three and a quarter times the performance/capacity?
Goddam right there's nothing new there. I did those in 1999.
Interesting release mechanism on the COM model.
No. It's not. You want interesting get a Lockout Release. You want something that works get something that wasn't "designed" to look like a Schweizer release.
My concerns are...
Who the fuck gives a rat's ass what YOU'RE concerns are. You just use whatever everyone else does.
...the tie wraps longevity and how it fastens to the control frame.
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.
Got any concerns about bicycle brake levers and how they're "fastened" to the control frame with velcro?
How long are you planning on leaving the tie wraps - and your glider - baking in the sun?
I always twitch a little when duct tape and tie wraps are used on ones "lifeline"
but I guess I trust a lot plain ol' kite string too...
Hell I've literally shoved the control frame out in front of me to avoid a whack when it got a little ahead of me in a light DW landing, similar to when I've had to slide it in on my belly (did that once after a weaklink brake coming off a launch cart.
Looks nice and simple! I like the little spring that pushes the pin out of it's housing when the towline isn't under any pressure. I too only use the last two fingers of my release hand Marc.
Jim Gaar - 2009/02/16 03:01:21 UTC
Tad free zone?...
I second that. Same technique for a few hundred incident free cart launches off 4 different styles of cart handles. Two fingers of my right hand on the lanyard.
I hail the new release. I see improvements over the competition. It's good to see progress in a sport rumored to be in it's golden years.
How wonderful it is that this release meets with your approval - the way ANYTHING in a picture ANYONE posts does - just as long as it isn't anything you think Tad has had anything to do with.
Zack C - 2012/01/26 23:22:58 UTC
The release in discussion is just the primary (cable actuated barrel). The tie wraps are not part of the release; it does not come with a means to secure it to the downtube. Joe recommends using a hose clamp, which is quite secure.
George Stebbins - 2012/01/27 01:17:11 UTC
And sharp. Not to mention, something else for stuff to get caught on. If you use a hose clamp, make sure the pointy parts are away from you, eh?
How much snag potential does a hose clamp present in comparison to a Quallaby Release brake lever?
I've always been happy with the Quest Air links, and only once did one break when it annoyed me seriously, and for no apparent reason. (Just as I crossed the treeline. I had to whip a 180 before I ran out of altitude to do so. Then I had an interesting landing, not really having room to turn back into the wind...)
I've had enough links break when they should to think mine is ok...
How much of a threat to the pilot are the pointy parts of a hose clamp on the downtube in comparison to:
The weak link is NOT there to prevent the glider from being overstressed on tow. OK, it serves that function too, but its main purpose is to release if you get too far off-line or some other issue causes the forces to become stronger than you, the pilot, can control. The forces become too strong for the pilot to overcome LONG BEFORE the glider gets overstressed. Does the weak link always do its job? Nope. On the other hand, making it too weak is a danger too. The key is to minimize risks. A reasonable weak link does that. It will seldom (but not never) break when it shouldn't. It will usually (but not always) break when it should. Different forms of towing use different strengths. And tandems need stronger ones regardless, because the tow forces are higher.
There are some folks who tow with very strong weak links. They are asking for trouble, IMO.
- some total idiot who tells him that the main purpose of a Questlink is to release him if he gets too far off line or some other issue causes the forces to become stronger than he, the pilot, can control?
- You wanna define "reasonable" weak links which allow you to safely cross a treeline but aren't so strong that the people who use them are asking for trouble in terms of Gs? Just kidding.
