JAS,

Sorry for the brief high jacking of your thread........

Jeff/Ryan,

I am not a composites expert by any means, and consider my CF laminate props a bit crude (but effective). I'll not start another thread, as what I do is brief to explain -
1. Roughen prop with 240 sandpaper
2. Cut 4 pieces of 3.5oz 24 thread per inch CF cloth (CF-141, http://www.cstsales.com/carbon_fabric.html)
3. Coat prop blade w/ thick CA, lay on 1 piece of CF cloth, "squeegee" CA through cloth using plastic baggy wrapped finger. Add CA as needed to ensure CF cloth is saturated, soak up extra CA w/ paper towel
4. Repeat for other blad surfaces, trim excess, lightly sand w/ 240.
5. Brush clear expoxy to fill weave, wetsand 240 between coats, and repeat until smooth surface is obtained.

That's it. I extend the CF cloth as far onto the hub as I can, with varied degrees of success. Clearly this is modifying the prop and potentially changing the stresses at the hub, and I don't know how this might affect the longevity of the prop. Thus far I have several props that are between 100 and 200 flights with no problems, and I've done this on several prop sizes including 11, 12, 13, 19, 20.5, and 21" props. For the pattern realm, my best estimate is that adding CF will have little benefit on a 21" prop turning less than ~6000 RPM, or on a 19" prop turning less than ~6700 RPM. Certainly vacuum bagging would be a better technique, but I've not ventured to learn that process to date.

Regards,

Dave