Balloon Powered Radial Engine

A simple 3-cylinder pneumatic motor.


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Run by just blowing air into it. Demonstration:

Exploded view in 3d viewer:

There's a LEGO compatible version of the motor:

If you like how it works, you can support me by purchasing the Pneumobile chassis: (3d Viewer:

Extra parts needed:
- M3x8 Bolts (x15)
- M3 Nuts (x15)
- Thin Nitrile Gloves (thumbs from M sized gloves worked the best)
or Silicon (worse) or PET (not tested) ones

Optional parts:
- M3x12 or longer bolts (2x)(for the gears)
- M3 Nuts (x2)(for the gears)
- 6x4mm Silicon Pipe (can be found in aquarium shops)
- M5x10mm Washers (x2) (instead of printed ones)
- 105ZZ Bearings (x2) (noticed no difference in performance)

Parts with "X_" in their names are optional.

- Use 3d diagram as a guide:
- Cut off a glove finger tip (thumbs from M sized glove worked well)
- Pull it onto a Cylinder_Ring (Use Helper_Finger to leave enough height)
- Connect a Piston to it with two Washers
- Clamp the Cylinder_Ring between Cylinder_Plate and and Cylinder_Lid
- Clip them with Helper_Clamp so they won't fall apart at once
- Bolt them together to Plate_Top
- Repeat for the other 2 cylinders
- Insert th Crank with 2 Washers
- Fix it in place with Frame_Bottom
- Bolt all the parts together
- Put the Valve_Inner in place
- Bolt the Valve_Lid into place
- The engine should be running!

1. Rotated freely by hand, but struggling when working - the inner valve may have too much friction against the frame (sanding the valve and the frame may help for a while).
2. Jams on a certain cylinder - this glove finger may need a bit more slack.
3. Isn't rotated freely by hand - gears bolted too tightly to frame (should have a bit of play), some gear teeth didn't print very well, or the whole gear printed with "elephant foot" and runs too tight with another gear.

Materials and methods

Printed well with 0.6 nozzle at 0.2 layer height. Some parts (Cylider_Back_Lid and Valve_Lid_6mm) need supports. After printing cut away the brims from Cylinder_Ring parts.



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7e0135d3434142e0eab6bf6202da7f8a?default=blank&size=40geraldine added this to the Lab & Science stuff collection ago
7e0135d3434142e0eab6bf6202da7f8a?default=blank&size=40geraldine added this to the Toys & Stuff collection ago
Mini sp logo grain 400x390Stamos added this to the Toys collection ago
B5dba5cd684b5d848f4474eb408715e7?default=blank&size=40regina rcflyer added this to the my collection 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 mecanique collection ago
Ff2fe8ad11e7e91177ea36308d7c62b2?default=blank&size=40DLOW added this to the Engine collection ago
Mini tt40wjsvo9g  2 Slava published this design ago