Hello! I recently purchased a 91 FX and I'm thinking about breaking it in this weekend. What is the recommended prop for break-in? Also, the manual states that the smallest prop for sport flying is a 15x8 and the largest a 17x6!! I mean, they must be joking, right? I'm going to put it on a Cap 232 .60-size so I'm thinking about running a 15x6 or something close to that.

Cheers!

O.S. makes their prop recommendation based upon noise restrictions around the world. You can run a 13 x 8 prop, but you'll get a lot more noise. If you prop the engine to run with a max RPM in the high 11,000's, then you can try different props. The suggested props, though, let the engine run very quietly.