Not everybody flies "3D"...

It is the newest version of the ASP, the square one... I just got a couple of weeks ago from J'En.

The engine was intended for a prop jet... the heaviest prop it is going to see is probably an 11x9!
The 11x7 is a break in prop, and suits the engine just fine: turning up to 14000 rpm... while still rich. It is a ringed engine after all.

And Dave is right: the engine is over compressed, or perhaps the squish clearance is too large.
I have been running 80/20 castor fuel through it, it does not work on 15% nitro. After break in (if I can ever get it broken in) 2 or 3% of nitro is probably all that's needed to clean up the transition.