Slight redesign of the V2 engine, this is a 3D printable pop pop boat engine.

Instructions for printing and assembling are identical to the V2: https://www.thingiverse.com/thing:3096028

Included in this is a really shoddy boat design. I could not get it to hold water on my first print, using the same PETG I used for the engine. I plan on retrying it in PLA. If you can get it watertight, all that is required are some tight bends in the tubing for the engine and a dab of glue or sealant to keep water ingress from occuring through the port tube tunnels.

This version of the engine has a thicker top, and a larger boiler volume. I found that the top would sag after running my one-hour torture test on the V2 engine, so I decided to add 1mm to its thickness. I also increased the volume because I believe it would add more thrust, I have yet to determine that but I have tested the V3 engine in both PETG and HIPS filament and it seems to hold up just fine now.