I was introduced to Stirling engines at the 5th annual Cabin Fever Expo on 1/27/01 in Lebanon, PA. I have an interest in design optimization and was challenged by the task of further simplifying a conventional Stirling. At first I concluded that substantial work had already been done to create the simplest possible design and that a large simplification was not likely. A few weeks later the idea of placing the flywheel inside the chamber occurred although at first I did not see how it could work. Then the full picture fell into place, benefits were analyzed, and finally a CAD design and construction began. The prototype first ran on 4/8/2001. By 5/6/01 the engine ran with a differential of approximately 17C. On 5/12/01 the differential was reduced to 8C. (I estimate that further reduction should be relatively easy to achieve with better precision machining and some small alterations.) This is my first engine.

I would like to thank Larry Simms of Thailand for his technique of using brass tubing for the cylinder and James Senft for writing his excellent books on Stirling engines.

Following are some possible variations and ideas for future development:

• Build an HTD version
• Optimize the design mathematically (the current prototype roughly follows Senft's LTD measurements). For example, a thinner chamber may be more effective and a smaller diameter piston should work better.
• Reduce gap between displacer and plates by making displacer more precisely.
• Improve seal mechanism to reduce its friction.
• Add a method to increase chamber air turbulence.
• Add a method to achieve an advantage similar to regeneration, if possible.