Paul Wrote
BTW As Vance says, larger dia., slower turning props are better.
Trouble is you need to start with a lot of ground clearance and most kit
planes
landing gears are designed up for the 68 to 72 inch diameter props.

Wrathall Mark wrote:

THis is what I meant. Given that a plane may be designed to give ground
clearance to a 68" two bladed  prop at 2800rpm (the equivelent three blader
for the lycon would be say 63" and less efficient) , maybe it would be more
efficent to run a 68" three blader at say 2400rpm - because we can!

Lower tip speeds, less noise, possibly the same efficiency, less blade
erosion.

Mark Wrathall

The history of installing three blade props on given two blade engine/airplane
combinations is better climb, less noise and vibration but lower top speed.

Paul Lamar

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