goneill wrote:

Big point ,the bungee effect is VERY DESIRABLE at the initial
acceleration and rotation into the full climb,this is where the extra
height is coming from ,

There is a small club in South Africa using a low cost plastic fibre
rope for auto towing.

Their operation is different in that they lay out the rope, then
deliberately loop back a specific distance (about 50m I think) on the
tow car end of the rope. When the launch commences the tow car
accelerates at full power. When the rope becomes taught, the tow car is
already moving at speed. The elasticity in the rope over its entire
length absorbs the shock of the take up. The pilot experiences rapid
acceleration and take off, not unlike a good winch launch. By the time
the glider has rotated into a normal climbing attitude the car and
glider are moving at constant speed and the launch proceeds normally.

The advantage of the method is that it eliminates the long ground run
associated with auto tow and there are no hesitations from gear changes
etc.

I believe they fly mainly K6 and sometimes K7. The reports I have heard
are positive, but I have not seen the operation and I don't have any
details. I can't comment on how effective or safe it is.

Happy New Year.

Ian