Napier’s two-stroke 18-cylinder diesel engine is one of the most diverse—and insane—combustion engines ever produced.

Click to open image viewer. Type: Reciprocating, 18 cylinders, radial, air cooled, two rows, gear-driven 1-stage, 2-speed supercharger Power rating: 1,790 kW (2,400 hp) at 2,800 rpm Displacement: 45.9 ...

If you look at aircraft from the Second World War or earlier, you'll notice that many of them have engines with large frontal areas and cylinders arranged about the propeller crankshaft. This a radial ...