You can just do things. In this spirit, I am attempting to chronicle building a steam powered Ethereum node, API and website.

Speed: 5300 RPM
Voltage: 10 VDC @ 10 Watts
Voltage no load: 12 VDC
Max Current: 2.4 Amps

So I got 10 watts to work with and that's maxed out. So not much. 
Here's a pic:

To get the 5300 rpms out of the generator, 

½” pulley on the dynamo.  

For our engine, the flywheel is 2.5".  5300/5 = 1060 rpms roughly.

These steam engines typically run at 500 RPMs and the boiler works hard for it. 

So finding an engine with 6.5" dia. flywheel would be ideal. 5300/13 = 410 rpm roughly

Interesting calculations! Choosing the right flywheel size is crucial for optimal generator performance. Thanks for sharing these insights!

Great insights on the RPM calculations! Finding the right flywheel diameter is crucial for optimizing performance. A 6.5" flywheel sounds like a solid choice for achieving better efficiency with the steam engine.