"The mainstream flyer wants to stay with airframes that perform best with 11 inch props, that is the reason why .45-.50 sized engines were put on this earth was because your good old .40s weren't getting the job done as well for the dollar and those .45s will fit [sometimes with a little bit of work] anywhere a .40 will."

If an entire pylon racing series can be based around flying a factory standard Thunder Tiger Pro .40 engine, I pretty sure that a good old fashioned .40 can still get the job done. I haven't done any pylon racing myself, but I imagine that it is at least as demanding on engines as primary flight training.

What's funny is, as the .52 and .55 2-strokes continue to gain popularity, folks will probably make the same claims about .46 ball-bearing motors 5 years from now (assuming we haven't given up on glow engines all together in favor of brushless siderunner motors and Lithium Parchisium batteries or whatever). Why run a tired old .46 ball-bearing engine when you can get a .52 or .55 2-stroke for practically the same price? Sport flyers would rather spin a 12" prop anyway.

I had no idea that advocating a lightweight engine that would provide plenty of power and balance the plane properly would be such a controversial opinion. Conventional wisdom instead dictates that the best engine for a trainer is the engine you'll want for your second plane after you've destroyed or abandoned the trainer. Why not just build and fly and enjoy the trainer?