U Can Do 3D
I have a YS 91 on mine and it has plenty of power.
So Far I have not had any problems with the engine being mounted inverted. Starts easy and runs well. Prop 15X6 APC, 30% Cool power heli fuel. Mine hovers at a little over half throttle. I do not know where the C.G. is. I just kept adding tail weight unitl the plane would hover easy and waterfall.