Posted by Michael Gilligan on 06/12/2021 17:07:25:
Please forgive my digression in this first response 
This page by Doug Self [yes, the audio electronics guru] has a wealth of information about rotary steam engines :
**LINK**
http://www.douglas-self.com/MUSEUM/POWER/rotaryengines/rotaryeng.htm
MichaelG.
.
Edit: __ correction this third response !
Edited By Michael Gilligan on 06/12/2021 17:08:35
There's also a quantity of material about Unusual Locomotives, Unusual I.C. Engines, and other stuff likely to be of interest to forum members – thanks, Michael, that's my evenings for the first part of the week sorted..
..edited because I'd underestimated the range of interesting stuff.. ..it's great..
Edited By DiogenesII on 06/12/2021 17:58:46