Shok-
You're missing the point. Nobody's saying the engine won't scream. They're saying the hp claims are bogus, and they are. I promise you that the O.S. 50 would pull your plane better than the .46. I'll give you an example: I bought an Enya 50CX to power a GP Super Decathalon. Then on my next project (an RV-4) I bought the OS .46FX. I bought the OS because the claimed hp were more than the Enya claimed. Yet the Enya can turn a 12X6 with authority while the OS is more comfortable with an 11X6. The manufacturer's trump up the hp claims to sell more engines. They're basically putting a flat stick on for a prop and seeing how many rpm's they can get. The higher the rpm's the more hp they can claim because hp is a function of velocity. Since you don't, however, fly your plan with a stick for a prop, the hp claims amount to nothing.