ORIGINAL: alex7403
if you are talking about the ARF:
Tower trainer 40 ARF with 61 FX not a good idea.
i'm not sure the tower trainer 40 ARF engine mount would accept the 61 FX!!!!
and the fire wall is designed for that mount only!!!
Actually it works just fine.
The FX is not as powerful as a .55 AX so there is little additional stress on the plane.
It fits and mounts w/o problems.