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

At 11:54 18 February 2014, Pieter Oosthuizen wrote:
Thanks Chris - appreciate your comments!

Apologies if I interpreted it incorrectly.

PO

I think Chris has made it pretty clear that the fitting of an automatic
system is not at this time a practical solution. I think he has also made
it pretty clear that once the sequence starts the result, as far as the tug
is concerned, is inevitable.

This is one of those situations where tug pilots are going to have to
decide what risks they are willing to take. I would support any tug pilot
who said that he would not tow a glider on a CoG or Compromise hook. On the
other hand I would not tell him he could not do it. There is also a
responsibility for those of us who teach aerotowing to really get across to
students the danger, to the tug pilot, of getting out of position. I am not
sure we have done this in the past, I know I have not been as pedantic as I
should in getting this point home.
Tug pilots do not always know the people they are towing so they are
perhaps not aware of the experience, or lack of it, of the pilot on the
back. In those circumstances the saviour should be the authoriser. We all
know that does not work. Perhaps tug pilots need to be more circumspect in
who they are prepared to tow.

On Tuesday, February 18, 2014 7:17:16 AM UTC-6, Don Johnstone wrote:
At 11:54 18 February 2014, Pieter Oosthuizen wrote:

Thanks Chris - appreciate your comments!



Apologies if I interpreted it incorrectly.



PO



I think Chris has made it pretty clear that the fitting of an automatic

system is not at this time a practical solution. I think he has also made

it pretty clear that once the sequence starts the result, as far as the tug

is concerned, is inevitable.



This is one of those situations where tug pilots are going to have to

decide what risks they are willing to take. I would support any tug pilot

who said that he would not tow a glider on a CoG or Compromise hook. On the

other hand I would not tell him he could not do it. There is also a

responsibility for those of us who teach aerotowing to really get across to

students the danger, to the tug pilot, of getting out of position. I am not

sure we have done this in the past, I know I have not been as pedantic as I

should in getting this point home.

Tug pilots do not always know the people they are towing so they are

perhaps not aware of the experience, or lack of it, of the pilot on the

back. In those circumstances the saviour should be the authoriser. We all

know that does not work. Perhaps tug pilots need to be more circumspect in

who they are prepared to tow.

It occurred to me that attaching the tow rope to the tug near the center of gravity (top of turtle deck on a Pawnee for example) would make kiting a non-event. That's how all the RC gliders are towed since you cannot control the position of the glider really well in relation to the towplane while standing on the ground. Interference of the tow rope with rudder and elevator does not seem to be a problem for RC fliers.

On Tuesday, 18 February 2014 11:25:24 UTC-5, wrote:
On Tuesday, February 18, 2014 7:17:16 AM UTC-6, Don Johnstone wrote:

It occurred to me that attaching the tow rope to the tug near the center of gravity (top of turtle deck on a Pawnee for example) would make kiting a non-event. That's how all the RC gliders are towed since you cannot control the position of the glider really well in relation to the towplane while standing on the ground. Interference of the tow rope with rudder and elevator does not seem to be a problem for RC fliers.


Um... wouldn't that cause a great risk of fouling the tail feathers of the tug? No more "boxing the wash".

At 16:41 18 February 2014, C-FFKQ 42 wrote:
On Tuesday, 18 February 2014 11:25:24 UTC-5, wrote:
On Tuesday, February 18, 2014 7:17:16 AM UTC-6, Don Johnstone wrote:
=20
It occurred to me that attaching the tow rope to the tug near the
center
=
of gravity (top of turtle deck on a Pawnee for example) would make kiting
a=
non-event. That's how all the RC gliders are towed since you cannot
contr=
ol the position of the glider really well in relation to the towplane
while=
standing on the ground. Interference of the tow rope with rudder and
elev=
ator does not seem to be a problem for RC fliers.


Um... wouldn't that cause a great risk of fouling the tail feathers of
the
=
tug? No more "boxing the wash".

OK here is a whacky idea. A V shaped boom with the point to the rear of the
rudder, the release mounted at this point. The two front points mounted to
a pivot, through the fuselage above the wing, near the CoG. The V
arrangement can pivot up, but not down. The space between the arms has to
be sufficient to allow full rudder. Would only work for low wing
monoplanes.

On Tuesday, February 18, 2014 1:50:52 PM UTC-7, Don Johnstone wrote:

OK here is a whacky idea. A V shaped boom with the point to the rear of the

rudder, the release mounted at this point. The two front points mounted to

a pivot, through the fuselage above the wing, near the CoG. The V

arrangement can pivot up, but not down. The space between the arms has to

be sufficient to allow full rudder. Would only work for low wing

monoplanes.

Well as long as were are drawing on envelopes, how about a bridle attached to each wingtip of the towplane, with the towhook at the apex of the bridle, able to slide side to side (to prevent rudder stalls) while the bridle pivots up during kiting so the force just pulls the towplane higher! To drop the glider, release one end of the bridle and the towhook just slips off.

Or just teach the stupid glider pilot to fly the correct tow position!

Of course, a good winch solves this problem nicely....

Kirk

On Tuesday, February 18, 2014 6:56:56 PM UTC-5, kirk.stant wrote:
On Tuesday, February 18, 2014 1:50:52 PM UTC-7, Don Johnstone wrote: OK here is a whacky idea. A V shaped boom with the point to the rear of the rudder, the release mounted at this point. The two front points mounted to a pivot, through the fuselage above the wing, near the CoG. The V arrangement can pivot up, but not down. The space between the arms has to be sufficient to allow full rudder. Would only work for low wing monoplanes. Well as long as were are drawing on envelopes, how about a bridle attached to each wingtip of the towplane, with the towhook at the apex of the bridle, able to slide side to side (to prevent rudder stalls) while the bridle pivots up during kiting so the force just pulls the towplane higher! To drop the glider, release one end of the bridle and the towhook just slips off. Or just teach the stupid glider pilot to fly the correct tow position! Of course, a good winch solves this problem nicely.... Kirk

The Dragonfly towplane for hang & ultralite gliders uses a bridle attached above the top of the rudder and just below the bottom of the rudder, withbthe tow rope free to ride up and down on the bridle. Hang gliders sometimes get way out of shape, but the tug isn't affected.
UH

On Tue, 18 Feb 2014 08:41:57 -0800, C-FFKQ (42) wrote:

On Tuesday, 18 February 2014 11:25:24 UTC-5, wrote:
On Tuesday, February 18, 2014 7:17:16 AM UTC-6, Don Johnstone wrote:

It occurred to me that attaching the tow rope to the tug near the
center of gravity (top of turtle deck on a Pawnee for example) would
make kiting a non-event. That's how all the RC gliders are towed since
you cannot control the position of the glider really well in relation
to the towplane while standing on the ground. Interference of the tow
rope with rudder and elevator does not seem to be a problem for RC
fliers.


Um... wouldn't that cause a great risk of fouling the tail feathers of
the tug? No more "boxing the wash".

From what I know of model aircraft I suspect, but can't prove it, that
the fin on an RC model is (relatively) considerably stronger than the fin
on a towplane. Structurally, most RC model fins are either solid balsa
sheet or a foam-filled fibreglass moulding. If its a sheet balsa fin its
almost guaranteed to be a lot harder and denser than I'd ever use on a
model I was building myself.

An RC model can be dumped on the strip in a manner that would wreck any
GA aircraft. They are very frequently landed this way. Rounding out? Whats
that? Land the model badly on grass enough to flip it over onto its back
and the fin is almost guaranteed to be undamaged. Could you say the same
about a typical towplane's fin?



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