Single Cylinder Air Engine Balloon Powered Rolling Chassis is a balloon powered vehicle based on my earlier air engine design (https://www.youmagine.com/designs/single-cylinder-air-engine). This vehicle can run over 40 feet on a smooth surface. My wife laughed so hard when this vehicle chugged through the kitchen and into the family room that, well, now there's six of them (hers is in red). Here's a video of the prototype: https://www.youtube.com/watch?v=e1hKDctlJkE You will need to purchase 4 "AS568" #219 o-rings (1 5/16" I.D., 1 9/16" O.D, 1/8" section) for the tires and at least 1 "punch balloon" (I found mine at a local party supply store, but they also are available on line). I've included quite a few photographs of various stages of assembly, I hope they help. 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 2+ Extended and an Ultimaker 3 Extended.