I had nothing backward. Using the propeller range recommended by OS I selected the 2 with the minimum pitch thus giving the least speed for a given RPM. The engine needs to maintain a proper load and under pitching it does not accomplish that. There is also no need to go to a 12 inch prop on a plane/engine of this size. Of course reducing the throttle is the best way to limit speed but we are talking about a new flyer here who is going to be tempted to "floor it" and the lower pitch will also slow the plane down better for landing and yet "pull" stronger for go-arounds