As a guide FAA states Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most adverse center of gravity, and with the propeller in the most adverse pitch position, may not be less than the following: (a) Ground clearance. There must be a clearance of at least seven inches (for each airplane with nose wheel landing gear) or nine inches (for each airplane with tail wheel landing gear) between each propeller and the ground with landing gear statically deflected and in the level takeoff, or taxiing attitude, whichever is most critical. In addition, there must be positive clearance between the propeller and the ground when in the level takeoff attitude with the critical [tire(s)] completely deflated and the corresponding landing gear strut bottomed.
Referring strictly to small taildraggers here, I have noticed that there are plenty of people out there that are reporting to be flying airplanes with less than 9" of prop clearance. Of these most are reporting 7-9", but occasionally as low as 6". These are for RV and smaller planes here. I suppose that anyone flying out of rough grass, gravel, etc. fields should put a premuim on ground clearance. But, for example, for those that intend to limit themselves to paved airports only, perhaps going a shade lower than the 9" standard is acceptable? Sent from my iPad
