In article ,
(Craig Freeman) wrote:

We recently converted from 3/16 7x9 cable to 3/16 plasma rope on our winch.
"Plasma", made from Honeywell "Spectra" fiber, seems to have some real
advantages over wire or cable. Some benifits include light weight, 11.48lbs
per thousand, (that's not much even converted to metric!!), hollow braid
(no twisting), 5000 lb breaking strength (that a lot even converted to
metric!!), 25% increase in launch heights. We operate from asphalt and
it seems to be holding up wery well. Expensive? Yes! However in our
environment it promises to far outlast steel which would make it cheaper
in the long run plus the added benifits. Sorry this sounds like a commerical
I was just so tired of that !@#$@#%%^# wire. If anyone else has any experience
with this stuff is there anything we should be looking out for?

Happy Winching,
Craig-



Well, I was waiting for someone from the Memphis club to post. However,
no one has so far, so I'll have a go.

The Memphis club purchased Glen Lawler's winch a few months ago. My
club, Southern Eagles, used this winch with excellent results for a
couple of years. We only stopped using the winch when we moved to an
airport with crossing runways where we had marginal room for the cable.

A couple of weeks ago, Glen Klingshirn and I had the good fortune to be
invited up to Memphis to train their guys on winch launching. Just as an
aside, I have to say that you won't find a better bunch of folks to fly
with. The hospitality and fellowship was superb. They are also making
the ultimate contribution to the future of soaring in the U.S.: The
Memphis Soaring Society has established their own field at Cherry
Valley, Arkansas. They are doing it right with a huge field, immense
hangar and a beautiful clubhouse under construction.

Anyway, the MSS has equipped one drum on the (two drum) winch with
Spectra. The original wire rope is on the other drum. After a few
launches with the cable, we switched to the Spectra and didn't look
back. The Spectra seems to give higher launches although we didn't do
enough launches with the wire to make a valid comparison. The Spectra
had no more noticeable stretch than the cable so we didn't have any
"bungee" dynamics to work around. To me the biggest, and unexpected,
advantage of the Spectra was that it did not have enough mass to throw
itself into a tangle. During training of new winch drivers, we had a few
incidents which would have put a tangle in wire rope, but with the
Spectra, there was never a tangle of any kind. The Spectra also seemed
to be holding up well through 30 launches or so. The only minor problem
with the Spectra is that it has so little mass that the cable end strop
would fall through the chute unless the winch driver got the power back
on quickly after the glider released. This was just a problem with winch
driver trainees and resolved after each driver got more experience.

It may be that exotic stuff like Spectra is not needed for a winch. The
dacron rope that we have used for auto launch is very similar in
appearance and has almost no stretch like the Spectra. It is also
abrasion resistant. It is not as strong as Spectra but is plenty strong
enough. It may do as well as Spectra on a winch and is cheaper.

Wallace (help stamp out winchophobia) Berry