It could be you're right but I'd still like to see an actual comparison with
and without the retrieve winch at longer and longer distances. Some
validated metrics would help sell the idea. It has yet to be determined
just how long ropes can be with a retrieve winch.

What I'm worried about isn't the weight of Dyneema/Spectra ropes it's the
pull angle at the hook. If the retrieve rope drags back enough to change
that angle it will adversely affect the height achieved.

I know an engineer who was working on a simple "spinner reel" type design
for a retrieve winch that would use 1 or 1.5mm Dyneema. Calculations showed
that the power required is minimal - you could power it with a small car
starter motor and a battery. 2000 meters of thin Dyneema would fit on a
drum not much bigger than a coffee can. With the "spinner reel" concept
Dyneema would pay off the retrieve winch with no rotation of the tiny drum.

On the bright side, using a retrieve winch would cut the fuel use by half.

Bill Daniels


"tommytoyz" wrote in message
...
Back in Germany we used two twin drum Tost winches on our field and
launched all day long back to back, as long as there were planes
needing to be launched. Wires were retrieved with a retrieve vehicle,
two at a time.

I think the British method of using a single drum winch in combination
with a retrieve winch to be a very sensible idea - even for long
fields and high launches.

The cable is being retrieved before it even hits the ground. So the
retrieve process is shorter and faster than using a retrieve vehicle
by dragging the entire cable length along the ground. The winch
retrieve should there for also save on wear and tear on the cable as
most of th retrieve occurs in the air after the glider releases.

On very high tows, a long portion of the cable is never wound up into
the tow drum and there for a high altitude launch should actually
reduce the cable retrieve process using a cable retrieve winch. The
light weight of the newer cables makes a launch penalty negligible.
The retrieve cable need not be very strong or even in good shape
anyway, as it's only function is to retrieve the cable.

I like this approach and seems the cheapest way to introduce high
frequency winch operations in the USA. I wish Commercial Glider
Operators would buy a single drum winch and a retrieve winch and offer
this launch method. Even at 10-15 a launch - it's still heaps cheaper
and the operator would probably make more money at the end of the day.

Not to speak about the fact that winch launches a far and away more
fun and exiting than aero tows.