Some useful links. I was a member of a club that did straight reverse
pulley autotow off grass, just a pulley on a rotating shackle on a chain
staked into the grass, and we used to launch a 22M Kestrel with that
system. You have to be carefull with initial rotation as acceleration is
not as fast as a winch - using a 2:1 and 3:1 pulley system might help
with that.
http://www.ukmsg.co.uk/wp-content/up.../SG-Dec-2013.-
Expedition-pilots-guide-to-aunching.pdf
https://www.youtube.com/watch?v=Q0rv1zOmyWg
http://www.pas.rochester.edu/~cline/...und-launch.pdf
http://www.coloradosoaring.org/think...launching/reve
rse_pulley/default.htm