Mike Hazel is now making carbon and fiberglass versions of the "first version" APC 7.8 x 6 prop. I have used the APC's on Quickie Rat, 36 AMA slow rat, and Super Slow Rat with good results. Unfortunately, these composite versions are illegal for Super Slow Rat, but they are still worth a try for other events.
Contact Mike at zzclspeed@aol.com, and ask for the "Scimitar 7.8 x 6". $15.00 each for glass, $16.00 each for carbon.