Neil wrote:
Ok, I could probably arrange with the winch driver to experiment, but is
there any definitive guidance on getting the greatest height off a winch
launch? (eg. Skylaunch).

i.e. if I'm "driven" at the higher end of the speed range acceptable to my
gliders placarding, will I get higher or lower than a lower speed launch?
I used to consider faster meant higher, but last weekend a most experienced
colleague said you'd end less high, as you spend less time gaining height.
I'm sure there's a set of graphs that would show a polar curve type
trade-off, but is there a simple way of looking at this?

If you want all of the gory mathematics, I suggest you join the Winch
Design Group at:

http://groups.yahoo.com/group/winchdesign/

Oversimplifying, "best" launch height will be achieved by maximizing the
tension on the cable while minimizing the drag produced by glider. With
a sufficiently powerful winch, the weak link establishes the upper limit
on the cable tension. Minimum drag is produced by flying at the best
L/D speed given the polar curve adjusted to the effective wing loading
of the glider, which is the weight of the glider plus the cable tension
divided by the wing area...

Marc