Alain Ducros has been sharing a couple of approaches to 3D printed Stirling Engines (check out his “Kit 1” version here) and this one is handy in that it can easily be dimensioned to suit the food containers that you select for the boiler cylinder.
Shared On YouMagine – Stirling Engine by Alain Ducros:
“Engine Stirling Gamma – KIT2 – The presented kit allows one to create a playful Stirling Engine in the spirit of a Lego construction set — working from printed parts, recycling classic food boxes, and a few off-the-shelf components….”