Turbine for a Jet engine model

A friend of mine asked if I could reverse the blades on a turbine for a jet engine model he was building. The original part had the blades pitched in the wrong direction. Each of the seven turbines slide onto a square shaft and nest one inside the next. Turbine was designed using OpenSCAD (took all of 15 minutes).

The model that these parts are for is the Smithsonian Jet Works Working Jet Engine Model.