barit1, in propellor 101 it is advanced that the most efficient propellor is one with a single Blade, (Obviously counterweighted) do you remember why?
It's because there's no wake interference between blades (for the same reason a biplane or triplane is aerodynamically less efficient than a monoplane)
Incidentally I've seen a photo of an experimental single-blade prop on a prewar light plane - a Cessna Airmaster I believe. The problem I believe is that it would need to be larger diameter, and thus turn lower RPM, to match the thrust of a multiblade prop.