Hydro Turbine blades - Scimitar shaped

I am designing a Hydro turbine and want to use scimitar shaped blades similar in shape to those used on the latest submarines - 6 scimitar shaped blades.
Obviously mine will be much smaller in the range of 500mm to 750mm in diameter.

Does anyone have a design I can download and print. If not do you know of any such design I can download and print?

Thanks

John Halsted