Two Blade Propeller

Fitting weather vane:
http://www.thingiverse.com/thing:42049

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This thing is fully parameterizable and meant to be customized before printing.
It is optimized for support-less printing (blades are oriented vertically)
and designed out of two parts so that even on small build-space printers pretty big propellers can be made. The appended *.stl file is only an example. Customize the model to get the biggest propeller you can print (almost twice the diagonal of your build-platform length).

One could print a lot of them as toy propellers in different colors all with different random parameters in reasonable margins and mount them on a kind of "wind sculpture".

### Ideas for improvement:
Right now its just a toy but one could:
* add grooves for ball bearings
* twist the blades
* generalize to 3 or more blades (4 non-coplanar should be easy)
* alter the blade shapes to something less classic but more fancy e.g. modify the blade to a more aerodynamic shape (NACA4)
* ma