ORIGINAL: Jaybird
I had an OS .61 on it before and it flew very well, better than with the Magnun .91. I had the ASP on hand from a recent swap meet so I figured I'd give it a try before anything else. I also run this plane on skis in the winter and have found the two strokes easier to run in cold weather. I don't have any gas experience and I'm not ready to invest in it at this point. Thanks for the input though!
Jaybird
I'm betting the .61 and the .91fs will fly the plane about the same. The plane does fly better with more power but it was designed for a .61 two stroke back in the day. I went from a YS 1.20 to an OS 1.20 and the OS didn't pull near as well as the YS so I went right back to the YS engine. If you liked the plane before with a .61 then it's the right engine for you. Not everyone requires straight up vertical, it's another choice thing. I just happen to like the performance I get with the YS 1.20. It's a perfect choice for me. Next one will use a 1.40 gasser but I'm thinking it may be over kill. If so I have a couple more of the YS 1.20s on hand.