Virginia What I have read is that 6-8 inches clearance should be considered a minimum for conventional/taildragger configuration, 4-6 inches minimum for tri-gear, with the understanding that these are absolute minimums. A hard landing and gear compression can use up this clearance in a hurry. You should also being always trying to land on the mains first in tri-gear, and either 3 point or wheel land you choice on conventional. Greater clearance is needed for the conventional due to the possibility of having a tail high wheel landing, and hitting hard. The longer the gear legs, the more chance of greater compression/more there to flex, so also keep that in mind. I believe the Grove gear is taller. The primary purpose I have read about the prop reduction units are not to be able to run larger props, but to take the loads off the engine crankshaft, and isolate them to bearings designed more for that load. Secondarily you also slow prop, allowing it to operate more in its range of efficiency, and you multiply the TORQUE (not horsepower) of the engine due to the gained mechanical advantage (similar to a car's drive axle ring & pinion gears).
Colin & Bev Rainey KR2(td) N96TA Sanford, FL crain...@cfl.rr.com http://kr-builder.org/Colin/index.html