Took out my Sportsman Stunt Speed entry today with great results!. Motorman was right about the prop. 8x8 was fastest with my old OS Max III. Got 21sec. for 7 laps inverted and 23 sec, upright. I will adjust tank height to get them the same. The engine was very happy at 13,200 on 5%nitro with 25% oil. Plane was easy to handle. Can't wait to see how she fares....Cheers,PhillySkip