CTE

[Rcmaster199 at aol.com]

In a message dated 11/25/2003 5:14:27 PM Eastern Standard Time, 
perkinsrx at centurytel.net writes:


> Subj:Re: CTE 
> Date:11/25/2003 5:14:27 PM Eastern Standard Time
> From:<A HREF="mailto:perkinsrx at centurytel.net">perkinsrx at centurytel.net</A>
> Reply-to:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> To:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> Sent from the Internet 
> 
> 
> 
> I see a reference to 40# Kevlar, which triggers a question. 
> What strength Kevlar is needed. The airplane pull-pull system I've seen 
> state 100#. I've read you can use Spiderwire fishing Kevlar but the strongest 
> I've seen in that is 65#.
>  
> This may be a dumb question, but I'm attempting to setup elevator pull-pull 
> for the 1st time & don't want to creat a problem with line that's too small.
>  
> thanks Eddie
> 

For pattern planes, 40 pound line is overkill by a wide margin. Several 
people are using my 40 lb PTFE coated Kevlar material on their larger 1/3 and 40% 
models. But it's difficult to make the line really small; around 40 pound test 
is easy to get

Typically it's hard to find smaller yarn than around 100 denier, that is cost 
effective. DuPont makes some pretty small denier yarn but even I can't get it 
easily. 400 dn yarn is fairly readily available and a few strands of this 
material are braided or twisted to make the necessary cable stock. But this 
material will have terrific strength and toughness, in the several dozen pounds 
pull area. 

Consider that one end of 400 dn yarn has a diameter of around .010" and 
around 25 pounds break strength. Four of these twisted together will be in the 80 
to 100 pounds break area, hence the 40 pound test. 

One more thing, carbon is considerably stronger than Kevlar weight for 
weight. However carbon doesn't have the leather-like toughness and resiliency of 
Kevlar and is no good as a pull cable unless it's in a carrier matrix.

MattK
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