For some time I've been wanting to design a "steam" engine that runs like a WWI Gnome rotary (e.i. the crankshaft is stationary and the block rotates).
Several years ago I was partially successful with a two cylinder design. Anyways, I've become much more accomplished since then.
I've finished a design for a five cylinder version. In my CAD software, it looks like it all works out. I plan on building this this winter, but attached are the plans if anyone would want to review, improve, and/or build it.
I've deliberately left off material types because you can use whatever you feel looks good.