IIRC, in the old days a ground launch signoff was required before the commercial glider test. We would do it once a year at the Soaring Society of Dayton (now Caesar Creek Soaring Club) at our Richmond, IN airport, which had 3 paved runways, including two with paved taxiways that we operated off of. 5000-5500'. This was the late 1960s and the age of the big block V-8 horsepower wars so someone always seemed eager to volunteer their vehicle to show it off (probably not a second time, though). We got high enough to do a full pattern in a 2-22. Because it conflicted with our normal ops, we tended to pick an overcast day, fairly calm. A Schweizer tow hook was mounted on the hitch ball and someone sat in the back to pull the cord if necessary. I don't think it was hinged to track the wire direction so I suspect it would have been difficult to release under load. The only drama was how fast the glider climbed compared with aerotow. The biggest problem was the old wire breaking every few tows. It was a big deal to lay everything out and splice the wire a few times so we never did it more than was necessary to get the ground launch sign off for whomever was going up for their test.

I've had a couple of auto pulley tows. Wild! Aileron control before the wing runner even takes a step. These were just to get high enough from a grass strip to turn out over the ridge so I don't know what it's like for a full tow.

Chip Bearden
ASW 24 "JB"
U.S.A.