Thinking back. That TT Pro-46 (which I still have but with a Perry Carb) was on my RCM-40 trainer when I got back into R/C after years out. It has been on four different models in it's career.

A ball-bearinged .46 is a useful engine for many, many .40 sized choices as a new pilot progresses.

An OS .40 LA is good for . . . a .40 sized trainer.

Maybe you want to pull floats someday on that trainer? Nice to have a little extra punch to pull that added drag.

Almost every prop plane in WW2 had a method of adding 20% or so for those times when it was desireable; whether it was a wire that could be "popped" by forcing the throttle or by blowing water into the cylinders. There are times when a little extra "oompf" is very, very nice to have.

The .46 gives a .40 trainer lots of climb, so the fledgling will soon learn to throttle back for level flight. See; it encourages good throttle practices from early on.