WW1 and some WW2 aircraft have piston engines with a large number of cylinders arranged radially in a circle. The prop is mounted on a shaft which appears to be central.
How do you connect 7 or 9 pistons to the crankshaft at essentially the same point? I’ve looked in books, I’ve looked on the net, I’ve sneaked under the rope barriers in museums for a closer look, but no joy. I have a mental image of very flat connecting rods like steel rulers, but it doesn’t seem likely.
Some of the engines (gnome engines?) appeared to have the crankshaft fixed and let the cylinders spin around the axis. How can the valves work? How d’you get fuel into the cylinders?