charles.harbert wrote:

Paul, there are approved method for making AC connections from composite

to

metal and I don't believe this is one of them. Using blind rivets or

screws

would produce point loadings which could loosen up the connection due to
vibration and torque reversal (4cyl/4 stroke). Once you introduce

movement,

composites fail very quickly because they can take the frictional heat.

Maybe,

as you've suggested, he's bonded the composite to a internal metal tube,

but

again it's not a normally accepted method.

I'm wondering why he is using a composite driveline, when an aluminum or

steel

tude would have been just as light and is a proven design. He's probably

making

<150 hp, so I hope he's done the calculations to be sure he's got enough

of a

safety factor.

Well I hope we hear from Charley soon. :-) I think carbon fiber is better
than metal for this application. Stronger and lighter and probably some
damping that metal does not enjoy. Lots of race cars are using carbon

fiber

drive shafts.

Paul Lamar

Charlie's drive shaft is not straight carbon fiber.  The core is an aluminum
tube.  It is wrapped with carbon fiber at a bias to make the tube much
stiffer in torsion.  This was done to raise the resonant frequency of the
drive line to above any problem frequency.   One more time:   Those aren't
rivets!

Tracy Crook
rws@altavista.net
www.rotaryaviation.com

 
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