Bob, The majority of the time I had an OS 61 FX in mine. ( I did break in a Saito 100 on it also) The only problem I had was not having a computer radio back then and the airplane wanted to tuck to the belly in knife edge. Since I couldn't "mix it out", I shimmed the trailing edge of the wing a little and it helped. I learned to use a little up elevator during knife edge and point rolls. Would be a non issue with a computer radio. The landing gear is a bit soft and hard landings will result in a trip to the bench vise The airplane eventually taught me how to "grease em' on"