Cánh quạt toroidal cho LEGO TECHNIC

Three models of toroidal propellers for LEGO TECHNIC.

Works in both directions, but one (noted on a side of props is better). 

How to print:

Printed without supports. Best results with nozzle up to 0,4mm and layer hight 0,1-0,2mm.

Print with materials which not shrink much, like PLA or PETG.

Designed to fit tight on axle. If tolerance of Your print is not suitable for lego axle just increase size in X and Y by 1-3%.

Some notes after play with propperlers:

Small has to be used in multiple prop setup or rev really high (to much for most lego motors).

Mid seize is most universal. Work best in most of the setups. 
Works the best with M-size power function motor when raves increased 10 times (2x 40:8 gears setup).

To power big propeller You need bigger motor or two medium size working together.