When I was learning to use SolidWorks, I went looking around the web for plans to build small machines. The idea was to use the plans to practice 3D modeling with SolidWorks. I found plans for this neat little Stirling engine at machinistblog.com. The designer is a man named Joren Jonkman. He has a YouTube channel with videos of many of the little engines he’s apparently made. I modeled all the parts, then assembled them in SolidWorks and even did some motion and stress studies on it.

💾 Download the SolidWorks files for this engine here.

What is a stirling engine?

A Stirling engine is heat engine. A heat source, usually a flame in these small models, is placed at one end of a cylinder. The air within the cylinder is heated and expands, causing the displacer to move. The moving displacer causes cooler air from the other end of the cylinder to move to the hot end. There it is heated, expands and continues the cycle.

It’s an interesting little engine. It works similar to steam engines but with far lower pressures. The downside is that it hardly produces any torque. Most of the applications of this type of engine have been to produce electricity. In the late 70’s NASA conducted some Stirling engine tests for the Department of Energy and built a functioning car with the engine. Stirling engines might see use on deep-space probes in the future. And one guy in Texas has apparently used the engine as part of a hybid powertrain design to get 100 MPG in a small SUV.