Originally Posted by
rspears
I referenced P&W for the R1820 but it was actually a Curtis-Wright design - nine cylinder radial, single row. Apparently the R1820 was also built under license by Lycoming, Pratt & Whitney, and even Studebaker during the war. The R3350 was two R1820's stacked, but used a slightly shorter stroke. Most had seven or nine cylinders per row, but I read that they experimented with an eleven cylinder design that never was used in production. Whoever thought of the single throw crank, master rod design was a smart cookie, in my book.