>> At some point Ralph flew my glider and was scared silly when it
didn't release, but unfortunately I don't remember if this was before
or after I rerouted the line.<<
I'm pretty sure it was before; in fact, I think I was the last person
to fly it that way. After my experience you got it looked at, and if I
recall correctly, that's what prompted you to change it.
~Ralph
================================================================
from: Vant-Hull - Brian (03/06/2005 18:35)
================================================================
I believe the problem is not with the method of pulling the release, but
the way the gate itself was configured with these models - the tow line
would end up pulling on the hinge and there was thus no force to pull the
gate open. There's a couple of ways to mitigate this problem by changing
the way the gate is suspended, but the problem is *not* with the loop pull
itself.
There's a line that connects the gate to the glider. If this line
attaches exactly opposite to the hinge, there's a good chance the tow line
will naturally pull against the hinge. If this is happening it's
imperative to reroute the attachment line.
I had problems with my pull loop release until I had the
attachment line rerouted. At some point Ralph flew my glider and was
scared silly when it didn't release, but unfortunately I don't remember if
this was before or after I rerouted the line.
There may have been other problems associated with not having
extra force from the lever effect of the bicycle release. Sunny or Adam
may know.
Brian Vant-Hull
301-646-1149
On Sun, 6 Mar 2005 mcelrah@verizon.net wrote:
>
> OK, Tad, you've blown me away with too much information - but the part
> about loop-type releases having a higher failure rate sure got my
> attention. What is the failure mode? Won't release or release
> uncommanded? I've had the latter, just learned to make damn sure the
> shackle is all the way on the gate. Let's get together at Ridgely or
> in town and work on replicating your rig - or making a Mark II... -
> Hugh
>
> On 6 Mar 2005, at 14:33, TadErcksn@aol.com wrote:
>
> >
> > Oh joy of joys! Finally the prospect of doubling the population of
> > this
> > system.
> >
> > Yeah, I welcome with open arms anyone - individual, park, manufacturer
> > - to
> > plagiarize this rig and keep all that R&D from going the way of Beta
> > tape and,
> > yeah, I'd be happy to be in the business if anyone would rather avoid
> > the
> > hassle him-/herself.
> >
> > I've got extensive documentation on components, loads, and specs and
> > have
> > written (and several times rewritten) an article. Kolie and Pauls
> > Adamez and
> > Gerhardt have been very kind to do some photo shoots but I keep
> > finding things I
> > should have set up better and really ought to go out with a tripod and
> > sacrifice part of a day before going to press.
> >
> > Re the first Paul's concerns...
> >
> > The spinnaker shackle doesn't fail in its function. If a reasonable
> > pull is
> > applied to the spring loaded latch the gate opens. (Caveat - I have
> > found
> > that a hang up of the weak link on the notch at the gate may occur
> > upon a low
> > tension release but it doesn't last long after a little tension is
> > restored.)
> > It's the activation and transmission elements that fail. Problems
> > I've seen
> > and/or had reported include improper adjustment of cable play,
> > insufficient throw
> > capability of the mounted brake lever assembly, and binding of cable
> > and
> > housing (the sort of problem that used to render a lot of ballistic
> > parachutes
> > inert). Although the loop activated flavor appears to be a pretty
> > reasonable
> > second-best, Sunny related that Highland has seen so many failures
> > that they no
> > longer sell them (your mileage may vary).
> >
> > The leech line based transmission, evolutionary variations of which
> > I've been
> > using since 1994, does not fail and is extremely efficient in
> > delivering the
> > force to where it's needed.
> >
> > Yeah, the scenario Paul described involving a two point system in
> > which the
> > primary fails and the bridle wraps could be a real nightmare -
> > especially if
> > the trim point is way forward on your keel (like mine). There was a
> > group of
> > tow pilots who hadn't thought things through more than the initial
> > step members
> > of which were deliberately releasing at the bottom end of the bridle
> > so that
> > it would stream better out of the way during free flight. When step
> > two
> > chanced along one of them had his glider fail under negative loading
> > and was lucky
> > to just get majorly injured.
> >
> > But in the course of conventional setups and operation this,
> > statistically,
> > just isn't on the screen - especially if you're using proper equipment
> > and
> > technique.
> >
> > Bridle wraps are rare and almost nonexistent if:
> >
> > the ends are cleanly spliced or tapered and it's of a fairly stiff,
> > inelastic, and substantial material;
> > weak links aren't stupidly long; and
> > releases are initiated under low tension.
> >
> > The wisdom I scored from Sunny regarding the last point is... At wave
> > off,
> > climb, dive to slacken the tow line, and release. The tow ring
> > (carabiner)
> > slowly falls away while the bridle gently feeds through it. (Also
> > eliminates
> > that annoying stall one experiences otherwise and the shackle doesn't
> > hammer
> > itself.)
> >
> > Further along - let's make this a worst case lockout scenario -
> > there's a
> > weak link at the top of the bridle which will now be experiencing
> > something along
> > the lines of a double load and a tug driver with a lever on that end
> > which
> > may do you some good.
> >
> > And, again, the technology has existed for over a decade such that no
> > one
> > should even be worrying about a primary release failure.
> >
> > And there's very little reason that we should have to let go of the
> > steering
> > wheel to try grab something at a bad time either.
> >
> > I also note in the 2005/02/21 installment of the Oz Report a reference
> > to
> > failure of the secondary bridle to feed through the end of the primary
> > after a
> > wrap. I've been using a painfully obvious remedy to that problem -
> > which also
> > prevents those components of your equipment from sawing each other
> > apart - for
> > over a decade as well. It involves a stainless steel sail thimble.
> >
> >
>
>
>
Re[2]: AT releases
Moderator: CHGPA BOD