Not doubting any of the above comments, but one time I was farting aroound with a .20~something (heck, it could'a been a .40~something, but I digress...) engine on a break in stand. I took our air compressor and blasted air into the prop as it was running to "simulate" flight (read: unload the prop some). Noticable RPM increase (understandable) I then (carefully) shot the air from the nozzle directly into the carb venturi and got a very noticable RPM increase, just as if it were supercharged...well, it was, just not a mechanically driven SC from the crank.

What about the OS Max 120 that was cupercharged with it's own little mini Roots blower? Wasn't it inline with the intake?

Neat topic, don't let it die.

Jon