This was at first just an exercise to learn FreeCAD design using formulas and parameters to design objects and turned out to be more. The basic shape and proportions of the Ugrinsky rotor is based on this image. Since I already had designed the blades based on this, why not actually test it in the real world? So here it is, it uses a NEMA 11 stepper motor as generator. There are two 6000Z bearings and a aluminium tube with 10mm diameter. I tested it and it runs pretty well without a load on the generator, I still have to test it with a charger connected. I think scaling it up to twice the size would work really well with the NEMA 11 stepper generator, but I would have to print the blades in parts and then assembly them. You can watch the system running on youtube