In a message dated 9/12/02 7:10:42 AM Pacific Daylight Time,
na9d@speakeasy.net writes:
> I assume the jacket on the Phillystran is UV proof?
Well, yeah.
> Kevlar does not do well
> at all when exposed to UV for long periods of time. It gets very brittle.
> How well does the jacket protect.
Fine? Good enough for tower guys.
>
> I also know from my sailboat racing that Kevlar stretches over time as
well.
> Anyone have any issue with that and Phillystran?
There is a published "General Stress/Relaxation" graph for Phillystran
HPTG. They say to "Tension the Phillystran tower guy assemblies to
approximately 15% of the ultimate break strength for the rope. Guy Tension
will automatically relax to about 10% of the ultimate stength and stabilize
at that point."
According to the graph, it looks like the initial elongation is pretty
much stabilized after the first 16 hours or so.
Kurt, K7NV, has made some comments on Phillystran elongation and I think
that they are on his website - <A HREF="http://yagistress.freeyellow.com/";>
http://yagistress.freeyellow.com/</A>. You can also find them in the TT
archives at <A HREF="www.contesting.com">www.contesting.com</A>.
Cheers,
Steve K7LXC
TOWER TECH
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