Does anyone use a tug tow hook that releases automatically whenglider kites?

Here's another idea that probably has something wrong with it.
Attach the tow rope to c/g, maybe the turtle deck and have a fair
lead at the tail which releases at the tail only under some set of unfavorable circumstances.

The glider can zoom without upsetting the tow plane nor will the glider be underemoniously dropped in turbulence.

Not sure about fouling the tail feathers with the tow rope.

Per Steve's comment that the only energy for the glider comes from the towplane engine I have a comment which is in many ways a request for enlightenment.
I had a kiting incident at Moriarty in my 27. All worked out OK, other than fright, mostly because I got off quickly, just as the kite began. How it began is not very clear at all, and much of this is later rationalization I fear, best I can come up with. Skilled glider pilots who watched failed to come up with much, if anything, that helps.
Tow began normally. Within first few seconds, both still on the ground, the tow plane bobbled a bit -- nothing that much given that this was Moriarty on a nice strong thermal day. When I hit the place where the bobble happened the 27 popped into the air a few feet.
My explanation is that I made moves that exaggerated what followed. Anybody with better ideas please join in.
I pushed forward on the stick, the glider began to react, as I flew out of whatever it was caused the bobble, the glider sank fast towards the concrete, so I (rationalizing) assume I moved the stick back to ease the bump.
The glider bounced off the concrete, not that hard but bounced. The one thing I believe I truly remember is that there was a bit of a snake in the rope -- ie some slack.
The tow plane was of course accelerating. So (rationalizing) as the glider bounces up I have at best neutral stick, maybe a bit aft still, and the slack comes out of the rope and the glider at this point began the early stage of a winch launch.
I know that I did two things quickly -- one was hit the release, the other was to get the nose down. Once at flying speed, at maybe 30 feet (I don't have any real guesses from the observers), I moved to the right to use the taxiway. Then, when the tow plane came in sight going like stink out of my way down the runway, I moved back and landed on the runway.
Not a scratch, including to the tow plane's prop. Good towing Mike Stogner..
My point is that there can be a hell of a lot of energy in the rope if for some reason it gains a bit of slack and is then turned into an elastic band.. For some strange reason weak links sometimes do not bust when they might be expected to ...






On Sunday, February 9, 2014 3:27:23 PM UTC-7, son_of_flubber wrote:
This topic was buried in a drifting degenerate thread. I'm wondering if anyone knows more about the tow hook innovation mentioned below by UH.



On Saturday, February 8, 2014 9:31:13 AM UTC-5, son_of_flubber wrote:



Why does the pilot need to pull the release if the glider kites? Why is the release for a deadly tow position not fully automatic? Is a simple purely mechanical, totally foolproof and 100% automatic release not possible? As the guy in the glider, I would be fine with a 100% automatic release. If I kite, release me immediately.





On Sunday, February 9, 2014 5:05:52 PM UTC-5, wrote:



There was a design and prototype of a release like this created many years ago and published, I believe, in Soaring magazine. I know if no one that has adopted this which makes it fairly clear that this is not perceived as a huge problem.

On 2/21/2014 3:23 PM, wrote:
Per Steve's comment that the only energy for the glider comes from the
towplane engine I have a comment which is in many ways a request for
enlightenment.
Snip...
I pushed forward on the stick, the glider began to react, as I
flew out of whatever it was caused the bobble, the glider sank fast towards
the concrete, so I (rationalizing) assume I moved the stick back to ease
the bump. The glider bounced off the concrete, not that hard but bounced.
The one thing I believe I truly remember is that there was a bit of a snake
in the rope -- ie some slack. The tow plane was of course accelerating. So
(rationalizing) as the glider bounces up I have at best neutral stick,
maybe a bit aft still, and the slack comes out of the rope and the glider
at this point began the early stage of a winch launch. I know that I did
two things quickly -- one was hit the release, the other was to get the
nose down.
Snip...
My point is that there can
be a hell of a lot of energy in the rope if for some reason it gains a bit
of slack and is then turned into an elastic band. For some strange reason
weak links sometimes do not bust when they might be expected to ...

Ropes indeed can store significant strain energy. Compared to poly ropes,
nylon rope is akin to a rubber band. Is anyone in the U.S. still using nylon
towropes behind their tugs? Real fun for beginning students and instructors...!

As to how that energy got into the rope...I'm with Steve.

Your written assessment sounds entirely plausible to me. Good job dealing with
your unwanted surprise.

Bob W.

At 22:23 21 February 2014, wrote:
Per Steve's comment that the only energy for the glider comes from the
towp=
lane engine I have a comment which is in many ways a request for
enlightenm=
ent.
I had a kiting incident at Moriarty in my 27. All worked out OK, other
tha=
n fright, mostly because I got off quickly, just as the kite began. How
it
=
began is not very clear at all, and much of this is later rationalization
I=
fear, best I can come up with. Skilled glider pilots who watched failed
t=
o come up with much, if anything, that helps.
Tow began normally. Within first few seconds, both still on the ground,
the=
tow plane bobbled a bit -- nothing that much given that this was
Moriarty
=
on a nice strong thermal day. When I hit the place where the bobble
happen=
ed the 27 popped into the air a few feet. =20
My explanation is that I made moves that exaggerated what followed.
Anybody=
with better ideas please join in.
I pushed forward on the stick, the glider began to react, as I flew out
of
=
whatever it was caused the bobble, the glider sank fast towards the
concret=
e, so I (rationalizing) assume I moved the stick back to ease the
bump.=20
The glider bounced off the concrete, not that hard but bounced. The one
th=
ing I believe I truly remember is that there was a bit of a snake in the
ro=
pe -- ie some slack.
The tow plane was of course accelerating. So (rationalizing) as the
glider
=
bounces up I have at best neutral stick, maybe a bit aft still, and the
sla=
ck comes out of the rope and the glider at this point began the early
stage=
of a winch launch. =20
I know that I did two things quickly -- one was hit the release, the
other
=
was to get the nose down. Once at flying speed, at maybe 30 feet (I
don't
=
have any real guesses from the observers), I moved to the right to use
the
=
taxiway. Then, when the tow plane came in sight going like stink out of
my
=
way down the runway, I moved back and landed on the runway.
Not a scratch, including to the tow plane's prop. Good towing Mike
Stogner=
..
My point is that there can be a hell of a lot of energy in the rope if
for
=
some reason it gains a bit of slack and is then turned into an elastic
band=
.. For some strange reason weak links sometimes do not bust when they
might
=
be expected to ...

A while ago there was a discussion as to whether it was a good idea to have
one's hand on the release during the early stages of an aerotow as we do
for winching. I believe that we may have found a good reason for doing so.
It is clear from what everyone has said that it is vital that the glider
releases BEFORE it takes over the control of pitch on the tug, or at the
very least before the tug is pitched nose down. Searching for the release
may take more time than the tug pilot has. In most, if not all these
incidents the glider pilot survives.

On that note I do not think it is of any importance whether the tailplane
on the tug stalls or the glider overcomes the available power of the
elevator, the mechanism is not important, the important thing is that the
tug is pitched nose down so far that considerable height is needed for
recovery.

On Sunday, February 9, 2014 5:27:23 PM UTC-5, son_of_flubber wrote:
This topic was buried in a drifting degenerate thread. I'm wondering if anyone knows more about the tow hook innovation mentioned below by UH.



On Saturday, February 8, 2014 9:31:13 AM UTC-5, son_of_flubber wrote:



Why does the pilot need to pull the release if the glider kites? Why is the release for a deadly tow position not fully automatic? Is a simple purely mechanical, totally foolproof and 100% automatic release not possible? As the guy in the glider, I would be fine with a 100% automatic release. If I kite, release me immediately.





On Sunday, February 9, 2014 5:05:52 PM UTC-5, wrote:



There was a design and prototype of a release like this created many years ago and published, I believe, in Soaring magazine. I know if no one that has adopted this which makes it fairly clear that this is not perceived as a huge problem.



Although FAA approval might be an obstacle, a system that would work would be to connect the elevator cable to the tow release cable such that the last small increment of travel toward full up elevator of the tow ship would pull the release.

An additional concern that tow pilots should be aware of is the possibility of an accelerated stall right at release of a kiting glider. With full back stick the angle of attack might increase so rapidly the tug pilot wouldn't get the stick forward fast enough.

On Saturday, February 22, 2014 8:04:43 AM UTC-5, Karl Striedieck wrote:
On Sunday, February 9, 2014 5:27:23 PM UTC-5, son_of_flubber wrote: This topic was buried in a drifting degenerate thread. I'm wondering if anyone knows more about the tow hook innovation mentioned below by UH. On Saturday, February 8, 2014 9:31:13 AM UTC-5, son_of_flubber wrote: Why does the pilot need to pull the release if the glider kites? Why is the release for a deadly tow position not fully automatic? Is a simple purely mechanical, totally foolproof and 100% automatic release not possible? As the guy in the glider, I would be fine with a 100% automatic release. If I kite, release me immediately. On Sunday, February 9, 2014 5:05:52 PM UTC-5, wrote: There was a design and prototype of a release like this created many years ago and published, I believe, in Soaring magazine. I know if no one that has adopted this which makes it fairly clear that this is not perceived as a huge problem.. Although FAA approval might be an obstacle, a system that would work would be to connect the elevator cable to the tow release cable such that the last small increment of travel toward full up elevator of the tow ship would pull the release. An additional concern that tow pilots should be aware of is the possibility of an accelerated stall right at release of a kiting glider. With full back stick the angle of attack might increase so rapidly the tug pilot wouldn't get the stick forward fast enough.

Full back stick is where I am during run up, beginning of take off roll, and commonly in the flare.
A combination of inputs might be made to work if including:
Climb power above some threshold
Plus some predetermind degree of up pitch control input
Plus some predetermined air speed.
Maybe find a way to add in a rate of deceleration input.
Maybe add reduction in G force for some predetermined time
If the combinations fall into the specified range, you have as problem.
Need is to avoid a single input that may be false.
FWIW
UH

I think the Aussies figured this out.

Nose hook on glider plus low tow (and suitable training for the high-low transition, which really isn't that hard) solves the problem.

Now, is the key part of the solution the glider hook position, or the tow position?

Without any statistics, my scientific wild-ass guess (SWAG) is about 80% nose tow hook on glider and 19% low tow; I'll concede 1% to training just because I know how poorly most glider pilots listen to any training when "safety" is involved...

Seriously, I think the key is to stop towing on CG hooks in turbulent conditions. Or at least tell the tow pilot when a CG hook is being used and make sure the glider pilot is fully aware of the potential for kiting. Perhaps insist that CG gliders go to low tow.

And if anyone thinks you can release a towplane Schweizer release under tension, especially with an upward component, I suggest that you try it on the ground. You may be unpleasantly surprised.

OT, been watching "Rake" (the original Aussie version) on DTV. Excellent!

Now, where is that Bearcat flight manual I've been reading?

Fun thread, hope is makes people think a bit about what CAN happen on tow, and saves a life or two.

Kirk
66

On 23/02/2014 01:35, kirk.stant wrote:

Without any statistics, my scientific wild-ass guess (SWAG) is about
80% nose tow hook on glider and 19% low tow; I'll concede 1% to
training just because I know how poorly most glider pilots listen to
any training when "safety" is involved...

I'd agree with that split. I'd also add that there are no Schweitzer
hooks in Oz. That helps a lot.

GC

Kirk 66

Apologies for this turning into a 2-33 rant that even jumped threads. The typical US trainer was brought up in another post to which I replied with a question. Have never tried to let go of the 2-33 stick on tow, thought others might have. Seems to me a mistake similar to that is what it takes to start an upset. Rare, yes. Fortunately so is the towplane upset.
Last experience in low tow 2-33 flying was landings on tow. It's a lot of stick pressure. But compared to modern ships it seems a lot of control pressure to do anything.
Like too many of us, I have lost a friend to a towplane upset. Many in Region 2 knew him.
Certainly in strong wave - and strong rotor - low tow provides a larger window to keep the towplane visible in. An invisible towplane should not have a glider attached.
My personal apprehension about low tow near the ground is from a low level, low tow accident I feel would have had a different outcome with another 20 or so feet of altitude to see and use the safe option. Instead the outcome was of the worst variety.
Jim

April 1981 Soaring, Safety Corner by Bob Gaines. Picture of mechanism and description. Was tested in England on an Auster. Read all about it on the SSA online archive.