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

Would a stiffer tube resonate at a lower frequency ?? Virg

Higher.

Paul Lamar

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