Doug’s research and development delves deep into the design of stirling engines running off of solar energy. The above video shows his engine model 3d purring along right nicely –

I’m in the process of performance testing the engine to see how closely its power output agree with my simulation. There are many sinks for losing power including: bearing friction on the rotating shaft, sliding friction on the piston and displacer shaft, compression leakage around the piston and displacer shaft seal, air friction on the air moving around the displacer, and air friction on the spinning flywheel.

My basic and inexpensive instrumentation for this operation includes a stopwatch and a bicycle speedometer used as a tachometer. Using engineering computations and these two instruments I can derive the friction based on how long it takes the unpowered engine to spin down.

Come see the efficient results of his labors at Bay Area Maker Faire – Solar Heat Engines

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Makerfaire Glassworks

Maker Faire is a two-day, family-friendly event that celebrates the Do-It-Yourself (DIY) mindset May 3rd and 4th at the San Mateo Fairgrounds, CA ( It’s for creative, resourceful people of all ages and backgrounds who like to tinker and love to make things. Buy tickets now and save, discount ticket sales end on April 25th, 2008.

If you’re in the Bay Area, or plan to attend Maker Faire add “makerfaire” to your Twitter, we’ll be giving away tickets and will have updates before and during Maker Faire!

In the Maker store:
Stirling Engine Kit