>>Optimum choice is a large diameter two blade prop turning slowly since a
>>one blade is too odd and harder to balance. Rotax has a gearbox to reduce
>>propspeed specifically to allow a larger diameter prop. If it were not
>>geared down, it would take a smaller diameter prop with maybe 12 blades to
>>absorb the horsepower, and that is not efficient at all. Otherwise the tips
>>would go supersonic , get really noisy ( like a Cessna 185 floatplane on
>>takeoff) and get real inefficient.
It is not possible to remove the yaw vibration caused by the upgoing blade
seeing a different AoA to the downgoing blade therefore generating less
thrust. This is unpleasant, makes things wear out quicker and increases
drag. 3 blades do balance and you can feel the difference.
BTW I am told that the 4 cyl Jabiru Europa was not a success, it had a 2
blade wood prop. Am I wrong? if so apologies.
Graham
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