This was intended as a vague comparison of prop size versus RPM.. intended to demonstrate that the user should use the correct prop size for an engine. Excessive RPM is not going to gain a darned thing except make more noise and perhaps destroy the engine.

Did you ever try a 9-6 on an OS .46? If not, how do you know it won't reach 15,000 RPM? I under proped an OS 61 one time and the result was an RPM range that was way to high and enough noise to upset those on the flight line, let alone the neighbors.

The point is to prop them correctly to get the best advantage out of that engine/prop/airframe combination.

CGr.