On Sat, 16 Dec 2006 00:22:18 GMT, "Roger Long"
wrote:

These kinds of discussion almost always take place without benefit of actual
prop calculations.

A two blade prop is inherently more efficient than a three blade. A single
blade would be even more efficient if there was a way to avoid the vibration
due to imbalance.

Counterbalance. I've seen single blade props on airplanes, motorized
gliders and even small RC aircraft. And I remember seeing a single
blade boat prop in an article online a few years ago but can't find it
now. It had a single blade and on the other side a rounded-off bulge
in the shaft as a counterbalance.

I think the reason they're not more popular is that they just look
strange.

Steve