On Oct 16, 4:41*pm, Andy wrote:
On Oct 16, 8:40*am, ContestID67 wrote:

*Someone check my math.

For constant acceleration the average speed for a run that starts with
zero speed is half the end speed. *The Escalade does 0-60 in under 10
seconds I think. *Assume 10 seconds and add 25% for the extra mass of
the glider and that gives a ballpark zero to 60 mph distance of
88*12.5/2 ft = 550ft. *That *leaves *enough room to get down and
stopped. *However, if the goal really was a turn back, I'd assume the
intention would have been to be at winch limit speed with as much
altitude as possible. *Guessing winch redline at 90mph that would use
up about 825ft. *Still enough to get down and stopped but not a
situation where I'd be tempted to try a turn back.

However, If the run reached winch redline at the point where the tow
truck had to start maximum braking to stop before the end, then the
runway available for a turn back looks much better. *At winch redline,
and with say 100ft of altitude, the available energy is looking
comparable to an aerotow rope break at 200ft. (Ballpark you have half
the potential energy but over 2 times the kinetic energy). *Someone
knowing the winch redline and the normal aerotow speed could run the
numbers.

Not saying I'd want to try a turn back under those conditions but the
idea may not be as stupid as some are suggesting.

Andy

I've done many auto tows with an aero tow rope but never in a scenario
like this. My tows were to just so I could glide down a long taxiway
to the ramp and stop in front of a hangar saving the walk back. The
climb was very shallow with a slack rope release when I thought I had
enough height - usually about 170' AGL. Then never a turn more than
30 degrees until touchdown. It was fun and safe.

This was obviously neither. I'm afraid it was one of those, "It can't
be that hard" situations. Excellent, in depth training is the key
to safe ground launch operations. Given that training, winch launch
can be safer than aero tow judging by the German experience. DIY
training can be deadly as we've seen.

Most ground launch accidents don't involve the launch - more than 80%
are landing accidents where the pilot gets safely airborne but can't
manage a safe landing. Usually, it's because the pilot had no plan if
the launch didn't go as expected. A launch failure doesn't mean a
safe landing is impossible - or even difficult.

The best this pilot could have hoped for is to be at 170 feet AGL
2000' down the runway then try for an aero tow-like turn to a downwind
landing. Doable? Maybe, by an experienced pilot - but with no safety
margin whatsoever.