“Single Cylinder Air Engine Smaller Edition is the smaller sibling of my previous Single Cylinder Air Engine here: https://www.instructables.com/id/Single-Cylinder-…. While Single Cylinder Air Engine Smaller Edition was designed as a test platform for another design, the test video I posted on Youtube caused a few people to message me to ask for the model, so here it is. I’ve included a video that shows this engine in a new design I have yet to complete. Having a smaller total displacement than my previous design, this engine runs longer on balloon power but as a trade off delivers less torque. Also, being smaller and having a crank shaft that is assembled in place requires even more fine scraping, sanding and/or filing and meticulous assembly steps to make this engine work at its peak efficiency, so be patient during the printing, preparing and assembly process. I probably forgot a file or two or something, so if you have any questions, please feel free to ask. Designed using Autodesk Fusion 360, sliced using Cura 2.3.1, and printed in PLA on an Ultimaker 3 Extended.”