Added a toroidal radial taper to the design, so that it would fit our little hand-held vacuum. Basically, it's taller in the middle than on the edges.
The scad is configured to print part of a hand-held vacuum, replacing an injection-molded part that blew apart under use. Also added variables to make the center hollow, which seems to improve suction, and of course sized it up for the vac in question, a Shark 18v Cordless.
If you've got a hand-held shark, odds are this is for you. To attach it to the shark motor, I heated the motor shaft and then press fit the part (PLA printed) in place.
The motor vibrates a bit more (the printed part isn't perfectly balanced), but it works, and with about 2 hours from openscad->part, it really sells the 3d printer.
For reference, the turbine I printed is 70mm diameter.