Has anyone ever checked the rotor speed of their machine? I just got back from the field made two nice flights on my Kellet The AK-2 There was a helicopter pilot there and he had a optical tach and he used it to check my in flight rotor speed This is a rotor with 36 inch Aerobalsa blades that I cut down to 2 1/2 inches wide I cut the undercamber off of the 2 3/4 inch blades Well on a slow pass the blades were turning 670 RPM on a high speed pass 820 RPM I would be interested to know if anyone has any comparable numbers There was a wind around 12 mph and passes were into the wind