ORIGINAL: rtc_71
whats a good prop for a norvel .061?
Depends a bit on: the plane, the fuel, the altitude, the particular engine, the weather and so on.
To go fast you need some pitch, maybe 3.5 or 4. But you still need RPM so you will not be able to use much diameter. So on a lightweight plane - maybe a 4.5X4 and increase / decrease the dia and pitch from there to optimize.
For "pulling power", more diameter and less pitch. Maybe a 6X2 or 6X3 to start.