Great engines and great planes

In time of peace a new aircraft engine is as much as two and a half years from the drawing board to an experimental job on a test stand, another year or more to Army acceptance, still another year or more to production in quantities. New planes normally are flight-tested, modified, retested, modified again and again before a production order. But of desperate necessity, the Air Force was trying to cut this time by two thirds. It did so. The new plane and new engine, unapproved as of January, 1942, knocked Japan out of the war in 1945. When Japan's surrender terminated Chrysler's contract, 18,413 engines had been built and shipped from Chicago. - p. 2-3.