"Bob Johnson" wrote in message
...
Hi Scott --

Plasma doesn't stretch, thank goodness. In fact stretchy winch lines in
general are bad news.
Bob

Except when using polyprop rope! That bit of stretch helps get to flying
speed very quickly
and into the initial climb sooner, therefore higher launches.
Allows the winch engine to get to full revs,drums and drive gear at speed
before the glider
starts to move, (giant flywheel) equals less loading on your engine at the
critical moments
At $160 per length,life 800-1000 launches its cheap too.A man can pick up a
kilometre
of rope so that gives you an idea how much less weight the glider is
lifting.

gary


plasticguy wrote:

Has anybody figured the effects of the
elasticity/stretch of the winch cable.
I seem to remember some references to plasma rope
instead of steel cable. This stretch probably
makes it easier to accelerate the drum to speed as the
line stretches. Now it the acceleration rates of the drum
and glider are non-linear at the start of launch, your calculations
of horsepower (should be torque) get really muddy fast.

Scott.