RE: World Models Ultimate 40S
G'day,
I first mounted a Magnum .52 FS inverted in mine and flew it for a few weeks. It was great! I then took the FS out and mounted a SuperTigre .45 2 stroke sideways with a Pitts and it is even better. I did have to cut into the front of the cowl to allow for the carbie, but it only meant enlarging the breather that is already there. I fitted a standard servo in the wing by mounting a plate to give it more height and clearance inside the wing profile. I have put larger wheels on her so she taxiis better and taken off the pants - they don't take much punishment and break up pretty easily.
DVM