I built one and flew it on a 25cc Homelite, and I liked the combination very much. I sold it last year after flying it for about three years. Flight was scale like and spirited. Remember, the original trainer was no slouch. I tried different props, and the best performance was with APC 16X8 and APC 17X8N. Your Ryobi should do well, also. You may need to engineer some firewall changes to handle the length of your engine, but it should be doable. my plane weighed around 16 1/2 pounds.,