I thought this would be a fun thing to model in Inventor. I downloaded the GOE 15 Aerofoil from the NACA site http://airfoiltools.com/airfoil/details?airfoil=goe15-il and scaled the coordinates accordingly in Excel. There are two variants - a one piece which entails picking out the support between the vanes with fine pliers or the two piece which need to be superglued together taking care to align the vanes using the fine pins and holes for general location and then fine tuning by eye. Loctite gel control superglue works a treat. There is a keyway for driving and also a shaft if you want to do a quick trial using a bolt in an electric drill. I am thinking of using this in a project where the impeller causes forced evaporation of Acetone inside an Acetone smoothing rig.