Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Stoker: that was a very interesting series of experiments you ran on those Sun motors !

I had the chance years ago to participate (as a low level tech) on two Stirling projects. But I didn’t even get to see the engines , just the proposed heat sources.
One was a NASA project to use metal panels to conduit a gas or liquid to the Stirling engine for heat. The second project was for Sandia National Laboratory involving trying to keep the reflective surface “shiny” on the reflective array (dust was a nemesis ).

I guess those Sun motors could have benefited from a “tracking” type tripod as used in astronomical telescopes to keep the dish aligned with the “moving” sun. But that little device would be kinda expensive over-kill for a toy /demo.
Still those Sun motors are fun to watch in action, and are an excellent engine example of what the 1970’s was hoping would solve an Energy Crisis  (or provide power for disco balls)

Today the marketing for those Solar/Sun engines might name them the popular 2020 buzzwords —— Systemic Free Range Diversity Existential Engines (or Little Greta’s how-dare-you motors)

1978 magazine cover