Toroidal Propellers

This past week the internet's been a buzz about  Toroidal Propellers after MIT won an award.

The toroidal propeller, one of the Lab's

@RD100Awards

winners, has a unique, closed-form propeller design that makes it a significantly quieter alternative to common multirotor propellers on commercial uncrewed aerial vehicles. http://ow.ly/yWA150MkbPw

https://twitter.com/MITLL/status/1611438712683958306?s=20

TOROIDAL PROPELLERS MAKE DRONES LESS ANNOYING
https://hackaday.com/2023/01/28/toroidal-propellers-make-drones-less-annoying/

Toroidal propellers: A noise-killing game changer in air and water
https://newatlas.com/aircraft/toroidal-quiet-propellers/

So I thought I would give it a shot 

My OpenSCAD script.   Not really happy with it. 

// johnsokol.com - Attempt to create a toroidal propeller M = [ [ 1 , 0 , 0 , 0 ],

[ 0 , 1 , 0.7, 0 ], // The "0.7" is the skew value; pushed along the y axis as z changes. [ 0 , 0.7 , 1 , 0 ], [ 0 , 0 , 0 , 1 ] ] ; multmatrix(M) scale([2,0.5,1]) rotate_extrude(angle = 360) translate([80,0,0]) rotate( -65) import("airfoil.dxf", convexity = 10);