barit1, in propellor 101 it is advanced that the most efficient propellor is one with a single Blade, (Obviously counterweighted) do you remember why?
To provide the same load a single bladed prop is larger than one blade of a twin bladed prop. Generally one big wing is more efficient than two small ones.
Model flyers who compete in the control line speed competitions frequently use single blade props.
Wait till it gets "on the pipe"..
http://www.youtube.com/watch?v=JGBHips72TA
...208mph.