Low towing thought

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On Mar 6, 4:38 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"Tuno" wrote in message

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This topic is most interesting. I was never taught the low tow, or
presented with the concept at any of the 3 places I took lessons
(Estrella, Seminole Lakes and Turf, 3 years ago). How is it easier for
the glider driver? Wouldn't it create more work for the tug driver?

Are there any enthusiasts of the low tow who are also enthusiasts of
high wing loading for those good days? I've been in the "low tow"
position unintentionally at max wing loading when the tug driver musta
thought he was pulling a 2-33. Seems like there would be no room for
error if one started out in that position, and the tug then slowed
down!

~ted/2NO

I probably flew hundreds of low tows at the old El Mirage Field. Gus
Brigleib insisted on low tow.

If you are flying a low performance glider, the technique for slack is to
just push the nose lower. The glider will just move down and take the
slack
out. If, however, you are flying a Nimbus, it will outrun the tug pasing
under it. Pulling up puts in more slack even as the glider slows down
ending in a jerk.

In the end, I suspect the reason Gus insisted on low tow was the TG-3's
he
used as trainers. It was very difficult for the instructor, sitting 8
feet
or so behind the student, to see the tug while in high tow. There was a
lot
of rollover structure and greenhouse canopy between the front and rear
cockpits. Low tow gives the instructor a great view of the tug. I
really
can't think of another reason for low tow.

BTW, low tow seems easier only because there are fewer references, like
the
horizon, to help detect being out of position. If you can't tell you
are
out of position, it seems OK. In fact, the opposite may be true. In
high
tow, the tugs wingtip vortices tend to push a glider back to center
position. In low tow, they tend to pull it out of position.

Bill Daniels

Gotta jump on this one- sorry Bill!
Suggestion of moving down to take up slack is absolutely wrong. This
will increase relative speed of glider and make the situation worse.
The usual reason for slack is glider quickly descending and thus
slightly overtaking tug. Just like what creates slack in high tow.
Proper technique when you get some slack is simply slide out to the
side until slack comes out. Then return to proper vertical position
and move back to center.
Since you are below the wake , vortices are not really and issue.
One of the nice parts about low tow is that you feel the wake on the
vertical tail as height warning instead of fuselage descending into
wake and causing glider to want to start out of position. 2-33 drivers
will recognize this scenario.
BTW- we've tried top stall the tug by pulling the tail down and not
been able to do it.
Cheers UH


Please note that I did qualify my statement with the phrase "low performance
glider". In the days I was flying low tow, it was rare to find a glider
with more than 30:1. The 2-22's were about 20:1. These glilders won't
accelerate as you nose down. As you point out, higher performance gliders
will over run the rope.

Wing tip vortices have a laminar far field effects that extends at least one
tug wingspan. I did some wing tip vortex turbulence studies in the 1960's
with smoke grenades on the tug wing. That was one of the results. It means
that the glider is always under the influence of the two wingtip vortices
coming from the tug whether the pilot can sense the turbulence or not.

An interesting experiment is to position the glider to one side while in
high tow. Then, keep the gliders wings exactly level with reference to the
tug but otherwise allow the glider to go where it will. The glider will
gently swing back to center as it is pushed by the wing tip vortex. Try
that in low tow and the vortex flow will pull the glider away from center.

Bill Daniels