in which the cylinders rotated with the propeller around a fixed crankshaft, was designed by the Seguin brothers in France in 1907 and marked the first complete break from traditional automobile engine design. Gnomes with varying numbers of cylinders and giving powers up to 180 horsepower were made in large quantities until late in the 1914-18 War.
fuel is forced into crankcase through the jet inside the crank at F, and enters the cylinder when the piston is at it's lowest position, through openings at A and B. The exhaust is through a large single valve which gives rise to the name "monosoupape" or single valve motor. Oil enters at C, through the stationary crankshaft, goes through the stationary crank at D, and floods the bearings at E.
the above was scanned from: Aircraft Mechanics Handbook by Fred H. Colvin, A. S. M. E. 1918 stamped on inside of front cover: Navy Department AVIATION BUREAU OF STEAM ENGINEERING Navy Department Naval Air Station, San Diego, CAL. "Commanding Offceers Copy" hand written. I also have a pretty good library.
typical radial engine connecting rod, But not Gnome,.
Note: all of the Gnome Connecting Rods are articulated.
This diagram answers a lot of questions, about how does a Radial Engine work.