Paragon 3 bladed propeller hub

[schneidp20]

I found a picture on this sit of the Paragon 3 bladed propeller hub. I'm intreged. Does anyone have more reading info on this unique construction? Specifically I'd be interested in any reading on how one would figure out the angles and build a jig for a router. Yes, some of us still build wooden propellers. The home-built hovercraft community typically builds their own props. Yes, crude by the master-pieces shown on this site, but they get the job done.

Thanks,
Dave