A propeller! I managed to find a perfect second hand 69" x 63" Sensenich wooden propeller off a Diamond DA20-C1. This has the correct SAE #1 mounting and 3/8" holes to fit my engine and propeller spacer. The pitch should give my target 150mph cruise at about 2450 rpm. This will be very much a cruise prop so I will have to see how take off distances work out. Worst case it should be possible to rework the prop to reduce the pitch by a couple of inches to improve static rpm. 
