I improved the parametric propeller, here. The fins are now ellipses which are twisted. I want to eventually make the fin profile customizable. I have it set up to print out straight on the print bed, and it works fine.

Try it out! It may take a while to compile in OpenSCAD or the Customizer.

I printed it out on a Makerbot Replicator using Makerware 2.2.0.46 using "High" settings with neither supports nor raft, with 50% infill, 4 shells, 0.10 mm layer height, Extruder at 230C, build plate at 120C, speed while extruding of 90mm/s and traveling of 150mm/s (acceleration is on, and I'm running version 7.0 firmware).

Worked great, looks great.