It doesen't matter which way the engnie is facing as long as the crankshaft mounted on center. With it mounted off at a 90 is may throw off your lateral bance a little bit but nothing a little balancing work won't fix. I think a 45 Deg angle would be perfect. BTW make sure you try the 12.25x3.75W APC prop with your 55AX. That is what I use and it is awesome for 3D stuff. Only downside is that most LHS don't carry that size. I got mine from Tower.