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Water wheel with venetian blind slats

3D model description

Parametric disc for repurposing plastic venetian blind slats from trash in a small water wheel, Banki-Michell style turbine, and eventually in an electricity generator.

First version in SketchUp more than one year ago, I publish it now, converted to OpenScad so you can describe your own slats, change the blades orientation, etc.

I'd love to see those disc cut out / milled of unused CDs or DVDs because trash cans are full of them (I don't know if it's possible to lasercut CDs on the non reflective side).

Short animation demonstrating some parameters variation :

Reference :

3D printing settings

  • Download banki_disc.scad
  • Adjust those parameters (lengths in millimeters) to fit your needs :
    disc_diameter = 100;
    disc_thickness = 2.4;
    blade_angle = 30;
    blade_n = 16; // number of blades
    blade_w = 2.5; // blade width
    blade_h = 16; // blade height
    blade_t = 0.5; // blade thickness
    bore_diameter = 8;
    nut_w = 10; // captive nut width
    nut_h = 5; // captive nut height
    nut_y = 9; // captive nut distance to center
    gs_slot_w = 6; // grub screw slot width
    margin = 3;
    plastic_saving = true;
    holes_number = 6;
    hole_ratio = 0.5; // 0 < hole_ratio < 1
  • Compile and Render, Export as STL.
  • Print 2 discs, insert captive nut and screw.
  • Mirror them, and upside down to balance the weight of metal parts.
  • Cut your slats at the desired length.
  • Insert them in the slots.
  • Assemble on your axis (8mm threaded rod with small filed flat for the grub screw, in my case).
    For a real Banki Michell cross-flow turbine, you'll also need a nozzle.
  • 3D model format: STL



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