Air Balloon Motor for LEGO

A simple 3-cylinder radial engine compatible with LEGO Technic.


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Demo and assembly guide:

Exploded view in 3d viewer:

Extra parts needed:
- Nitrile glove
- Air balloon

Takes 4m of filament to print (about 5h at 20mm/s on my snail of a printer).
Will print a bit prettier with supports (80deg. overhang, touching buildplate) and ironing.
Parts with names starting with "X_" are optional.

  • You can insert one balloon into another to get thicker walls. Meant for 2-walled balloon. Idles well with one (with a flywheel), but will hardly pull any vehicle.
  • You can use metal M5 washer instead of printed one
  • Found that PLA isn't the best material for the design: isn't very slippery, and "fluid" (the clips stop pushing the parts together with time)

Materials and methods

Printed well in PLA and PETG with 0.6 nozzle at 0.2 layer height.



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Dae9bd27ac5d0a8802b2c9c6d56d8c94?default=blank&size=40Boxi added this to the Lustig collection ago
F693f2c6c6f0a65f824bb6ff36edfb04?default=blank&size=40Alexander added this to the Kids collection ago
5a40efa8219a55fd06f31f5de26bb3ee?default=blank&size=40Dennis Blankenburg added this to the Dennis collection ago
Fe95768457f19c3321364210e6164180?default=blank&size=40Sampey added this to the PUPAZZI E GIOCHI collection ago
C5763e4f8f315077f38066524c1865a2?default=blank&size=40Mario Beaulieu added this to the todo collection ago
Mini 150609   casual portrait  square Telliria added this to the Takeo collection ago
Mini 12505777953 3f0527420a bXYZWorkshop commented ago

HOLY COW!! I'm blown away!! This is an awesome design! Thank you for sharing

Ff2fe8ad11e7e91177ea36308d7c62b2?default=blank&size=40DLOW added this to the Lego collection ago
Mini screen shot 2013 07 15 at 6.49.36 pmErik de Bruijn added this to the Things to print collection ago
Mini screen shot 2013 07 15 at 6.49.36 pmErik de Bruijn added this to the Cool projects collection ago
Mini tt40wjsvo9g  2 Slava published this design ago