Working Steam Engine Model (balloon powered)

This is a simple, functional model of a double-acting steam engine. Since PLA can't actually handle steam, it's technically a compressed air engine, but the design is very similar to how real steam engines worked. This model should run either with your lungs or with any regular party balloon, you don't need an air compressor. It also doesn't require any specific hardware, screws, lubricants, or glue. I clocked my engine at 340 RPM using a balloon and 750 RPM using my lungs, but yours may run faster or slower than that depending on how well your prints are filed and assembled.

**A video of it functioning can be found here:** https://youtu.be/LOnf8li0OwM

**Required Tools and Materials**
- Clippers
- Sandpaper
- Paperclips
- Tape

**Assembly**
You can find a video of assembly with instructions here: https://youtu.be/KDDj87Au3gc
I recommend watching the video before printing because it offers helpful print orientation tips and what does/doesn't require supports.

This engine has a 35mm b