RE: Looking for engine size suggestions for utter chaos 40
Last 40 I had I used the OS .46 FX. Today I would use the OS .55 AX. That's if I was buying a new engine for it. Your .40 FX will fly it and do all the pattern sequences without any problem so if your not wanting to buy a new engine then just use what you have. If you want more power after you have flown the plane then you can buy a new engine.