On Fri, 15 Aug 2003 19:37:14 GMT, Bob Johnson
wrote:


We appreciate the feedback. Your launch heights of 50%+ of the length of
towline laid out wins the prize so far. I wonder if your extraordinary
success has anything to do with the synthetic rope you're using. You
didn't say the typical wind strength you launch into and your airport
elevation, both of which can make some difference.

Most everybody else is reporting only 25-35%. If your numbers can be
verified, I believe you guys are really on to something. Could you
describe the rope a bit further, size, construction, etc?

The other club on my home airfield is also experimenting with PU cable
(Dyneema) since 18 months now. They have modified one drum of their
double-drum winch (afaik 280 hp), so there is a very direct comparison
between steel and Dyneema cable.

Overall the performance advantage of Dyneema is not overwhelming - on
a 3.400 ft runway the maximum height advantage is only 150 ft with a
light Ka-8 and subjectively less with an ASK-21 or DG-505. We are
pretty sure that the winch launch of the steel cable is already pretty
much perfectionized on this particular winch, which does explain the
little benefit of Dyneema.

On the other side, handling of the rope is vastly improved.

see http://www.aec-landau.de/


Bye
Andreas