The standard setup is to use a Schweizer hook which is rigidly mounted in
pitch and can swivel around the yaw axis. So, if the glider kites, it
exerts sufficient force on the release mechanism that the tow pilot may not
have the strength to pull the lever. It's also possible that, should the
glider get too wide, the axis of the release cable is too far off center to
operate the release. So... Stay in position on tow!

The Tost release does not suffer from this design problem. I've also seen
the Schweizer release mounted to a heavy duty gate hinge for use in ground
launching. This allows it to align with the axis of the rope so there's no
difficulty with the driver or observer releasing the rope. I don't think
you'd get such a system approved for mounting on the tail of an aircraft.

"son_of_flubber" wrote in message
...
Returning for a moment to the 19th century tow hook designs that are on
most tugs.

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.