Mike:
We've been doing quite a lot of research on the subject as an
inexpensive alternative to aerotowing. Everything I have read
recommends using a pickup truck like a Ford F-150 or equivilent. One
of the best sites we've found to date is
http://www.danlj.org/~danlj/Soaring/GroundLaunch/ also get the book
"Ground Launches" by Derek Piggott. According to what I've read if all
goes right you can expect 70 to 80% of the tow rope length in altitude.
We will be using a 6000ft grass runway with a 2000ft rope. So we are
hoping to get at least a 1400' launch once we get it worked out. Where
are you located? If you would like to contact me direct I can be
reached at (remove both of the * to email) email
me for my phone number if you wish.

Larry Lively, Del Rio, Texas