Since we've seen so many radial engines here on The Kneeslider, the Rotec radials used in the bikes by Jesse James and JRL Cycles, plus the radial being built by Russell Sutton, I thought it might be worth mentioning the Pratt & Whitney R-4360, a 28 cylinder radial built in 4 banks of 7, each slightly offset for cooling purposes. The first version had an output of about 3000 horsepower but the last supercharged AND twin turbocharged version had about 4300 horsepower. This was pretty much the end of the line for radial development before jets took over but what an engine!
A bit too late for duty in WWII, it was used in quite a few later well known planes, including the C-119 Flying Boxcar, the C-124 Globemaster, the 6 prop engine plus 4 jet engine B-36 and Howard Hughes' famous Spruce Goose.
I saw one for sale on eBay and just thought it was worth bringing to your attention. There are quite a few pilots among our readers but any motorhead has to appreciate what a thing of beauty this engine is.
Link: auction has ended