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Old April 26th 17, 04:30 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 4,601
Default Tow Plane Upsets......

Just thinking of the physics here and remembering that the problem is
with the upward vector on the tow rope exerting so much force on the
Schweizer release that the tuggie can't release the rope. The following
assumes enough altitude to recover, not early in the tow.

Now, if the tug's tail gets pulled up sufficiently, the force vector on
the rope is more aligned with the longitudinal axis of the tug than the
vertical, thereby relieving the release of the upward (with respect to
the axis) force. Therefore the tug should be able to release as his
nose gets pointed towards the ground. Am I willing to prove this
theory? NO...

Also, if the glider is being pulled down via its CG release, the wing
should be fully stalled given the AoA of the wing in a (near) horizontal
descent with the fuselage level to the horizon. Application of rudder in
the glider should immediately induce a spin allowing the combination to
gently descend like a maple seed. Am I willing to prove this theory? NO...

And, when the tug hits the ground, the glider is free of the downward
pull of the rope and the resulting fire will generate a thermal allowing
the glider to climb away safely. Am I willing to prove this theory? NO...


On 4/26/2017 6:26 AM, Tango Eight wrote:
On Wednesday, April 26, 2017 at 4:11:04 AM UTC-4, Tango Whisky wrote:
Le mercredi 26 avril 2017 03:45:04 UTC+2, George Haeh a écrit :
Yes, I know that's taught, but does anybody put the student high so that
release is required.

Just as with spins, there's a difference between being told what to do -
and
actually going into the situation.

Putting a student high so that a release is required would be plain stupid and reckless behaviour of an instructor.
Any exercise needs to be planned in a way that the student has some room for error, and that the instructor can recover the situation if the student finally fails to do so.
In a high position there is no such margin. There are situations which just can't be trained.

Bert
TW

What can't be trained is the dangerous divergent situation. Agreed on all else.

-Evan / T8


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Dan, 5J