On Thursday, February 21, 2019 at 9:15:04 AM UTC-5, Dave Walsh wrote:
..and another question: why do so many YouTube videos show the
glider pilot on tow NOT holding the release knob?
In fact it's hard to find a video where the glider pilot does hold the
release throughout the tow!
In a flapped machine that might require a flap change during the
initial stages of the launch it's understandable, perhaps for a few
seconds, but even after the flap change no one ever seems to hold
the release knob.
In the dim and distant past when I was taught aerotows they was
certain to be very loud angry noises from the rear seat if one let go
of the yellow knob. Has something changed in the instructor
manual?
Dave Walsh

Hanging on the release during aero tow is a bad practice. There's a newspaper article from 6 or 8 years ago featuring an unhappy glider pilot sitting in the wreckage of his Discus too high up in a sycamore tree to do anything other than wait for help. Yep, hung on the release, big bump, popped off much too low to do anything other than pick the tree he wanted to crash into. That one's in the ntsb database if you want to look it up. New York state.

Hand touching, but not grasping the release is acceptable. Hand touching release at beginning of take off roll is desirable, especially if without a wing runner. A lot of ships place other demands on left hand.

Winching is a completely different game. In a properly run winching op, an inadvertent release should never be an emergency, but a dropped wing is immediately life threatening, hence hand on the release is the norm. It's a fact of life that in many aero towing operations, an inadvertent release at 50 - 150' will be an emergency.

best,
Evan