RE: KAOS AND RELATED PLANES AND INFO
Matt, those two engines are very close in the actual power output. I watched a friend swap out his OS .61FX for the .50SX and both engines flew his .60 size Spitfire very nicely. But, there was one big problem. The .50SX is about 20% lighter making the correct CG difficult to achieve. Starting from scratch, work on keeping the tail light!