I went to the web site.
Very cool to see a nice web for the ST-5.
It must be getting close.
Very cool pics page.
I wish there was more of the insides of the engine.
Lots of old ones and models, too.
I was watching the pics of the belt systems running and the water pumps.
It occurred to me, the ST-5 would be especially good where the direct belt drive could be used instead of making generic power.
One example might be a large athletic dome stadium. Using the sun to turn the ST-5, and having a number of ST-5's turning venting fans. For major event places, I am sure expensive electric fans that crank at a switch would be nice.
But think of another place, that could be left on all the time, for daily use, maybe a train station. When the sun shines, and it is hot, fans automatically turn.