Thanks Vaughn,

I know where to find the FARs on the internet, I just didn't know
which ones I need to look for, thanks for pointing out the key ones to
me. Some of the biggest flight schools in Colombia including ours
operate out of Guaymaral airport just N of Bogota ( 4°48'45.00"N 74°
3'54.00"W in Google Earth), the runway is 1700m/5600 ft. A take off
there in a C 150 is nothing compared to aerotowing a IS-28B2 Twin Lark
or a Blanik L-13 with a Supercup... They have done it in the past and
I believe a Janus CM at times too, pretty scary. That's why we use a
Skylaunch 3 winch with a 502HO Chevy big block these days... 2000 feet
AGL in 45 seconds vs 10 or 15 minutes :-)

Markus