David,
The key is to get the CF oriented lengthwise to the boom, to get the maximum
bending stiffness. But UNI-CF alone will give the boom very little
tortional stiffness. Having the FG at +/- 45 accomplishes this. The
tortional stiffness is needed when side loads get applied to the tail.
(i.e. when a TLG gets launched).
Having the CF +/- 45, as you suggest will give you a very tortionally stiff
boom, but it be less resistant to bending. According to a book I have, the
45 CF matrix has a modulus approx. 1/5th to 1/8th the strength in the
0-degree direction along the boom, as UNI-CF does.
In short, if you want a boom that won't twist, go with the 45. If you want
a boom that won't bend, go with UNI.
Jon Stone
----- Original Message -----
From: "David A. Enete" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, July 08, 2001 3:14 PM
Subject: Re: [RCSE] C/F Boom Molding Question
> > >I would like to mold a thin walled 1" OD Carbon Fiber Tube.
> >>I am going to make a male plug and a two piece mold.
> >
> >This seems like an extremely labor-intensive way to make a tube.
> >I suggest John O'Sullivan's Rollfuz method:
>
> Why not just use a mandrel and CF braided tubing? Wax your mandrel
> (euphemism) or use a protective barrier. Slip the CF braided tube
> over the mandrel. Wet it out and extract as much excess resin as
> needed. Then just cover the whole layup with heat-shrink tubing and
> shrink it.
>
> That should give you 45-degree fiber orientation, a very nice outer
> surface, and no need for mold building or bagging. Or am I missing
> some important fact?
>
> - David
> [EMAIL PROTECTED]
>
> North Atlanta Soaring Association
> http://atlantasoaring.org/
>
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