HI Barry, I've been flying my Mayhem for a while and love it with the 110. I put my battery in the fuse a few inches behind the wing. Mine knife edges very well but hovers are tough. It wants to fall off to the left for some reason. I can't imagine needing a bigger engine than the 110 on it. I sold my G26 I had on my big boy and got another 110 but haven' t been able to get it up yet due to tuning problems. I seems to act differently every time I try to tune it. I'm gonna check the valves today and try tomorrow again at home before heading to the field. If I get it running well enough I'll fly take it and my mayhem. I just got a F 40S and a OS 61 FX (used) for it. I've got a bunch of mods to do to strengthen it before I fly it. Poorest quality I've seen on any ARF so far. Sig by far was the best hands down. I've owned four H9 models now the 40S, it's the worst. I bought some used HS 445MGs and HS5645MG digitals I may use them on the 40 is that overkill or what?