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[Towertalk] Phillystran break strength vs. diameter?

To: <>
Subject: [Towertalk] Phillystran break strength vs. diameter?
From: (
Date: Thu, 12 Sep 2002 10:21:06 EDT
In a message dated 9/12/02 7:10:42 AM Pacific Daylight Time, 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 
>  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="";></A>. You can also find them in the TT 
archives at <A HREF=""></A>. 

Steve   K7LXC

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