From: Richard Riley <richardNOSPAM@riley.net>
Newsgroups: rec.aviation.homebuilt
Subject: Re: Do Composites Fail? Was: Re: Skycar coming soon
Date: Tue, 23 Nov 1999 16:09:05 -0800

On 23 Nov 1999 20:51:59 GMT, robertr237@aol.compost (RobertR237) did
speak thus :

>>  This assumes it's not a solid carbon structure, which is used in
>>some applications.
>>
>
>No aircraft application that I am aware of uses "Solid Carbon".  The very word
>composite implies a combination of materials.

There is a substance that we won't ever come across in the homebuilt
market but which is used in high end aerospace - reinforced
carbon/carbon.  RCC fabrication begins with graphite cloth impregnated
with a phenolic resin and cured in an autoclave. The laminate is
pyrolized to convert the resin to carbon. This is then impregnated
with furfural alcohol in a vacuum chamber, then cured and pyrolized
again to convert the furfural alcohol to carbon. This process is
repeated three times until the desired carbon-carbon properties are
achieved. These materials feature the ability to retain their strength
at a temperature up to 2700C (4900F) in non-oxidizing atmosphere, low
density as compared with graphite and metals, high electrical
conduction and a low coefficient of linear thermal expansion.
 It's also really, really, really, really, really, really, really
expensive.  There's a good introduction to RCC at
http://fbox.vt.edu:10021/S/shkelly2/ccc.html

I won't comment on the rest of Eric's nonsense, except to say perhaps
what he means is composites don't yield, they reach their limit and
then they break.  That's true.  But it's probably not what he meant,
either.

Fortunately, I have a high capacity industrial class loonmeter.


Richard Riley		        	"Any meeting you can walk away from
Renaisance Composites			 is a good meeting"
3025 Airport Ave
Santa Monica, CA 90405
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