Just finished a new 6-cylinder radial steam engine - my own design, with a 1/2" bore and 1/2" stroke. I've built a number of kit engines (Stuart, PM Research, etc), and this is my first foray into building from scratch. I've always been intrigued by radials, and thought it would make a great project. Turned out well, even with the many many tedious disassembles/reassembles to get it right!
I've drawn up plans for it, and posted it with a build log up in the downloads section (plans are at the end of the log). Thanks to those who replied to my query last week about software to draw plans in, as well as all those posters I've learned from!