The Wright Aeronautical Corp. introduced the 9-cylinder, air-cooled, R-1820 radial engine in 1931. The Wright Cyclone R-1820 was a 9 cylinder, single-row, air-cooled radial engine. In general, it looks that the rear part of the crankcase is formed from two cylindrical segments. Developed from earlier "Cyclone" engines of the late 1920s, the larger and more powerful R-1820 produced 575 hp; however, engineers dramatically improved its, Wright Cyclone R-1820 Service/ Maintenance Instructions: Wright Aeronautical R-1820 Series Maintenance Instructions (1945) with photos, systems diagrams, charts, procedures etc. Wright Cyclone R-1820 engines were produced from 1931 until well into the 1950s by several companies under license that included Studebaker, Lycoming and Pratt & Whitney. The R-1820 was built under license by Lycoming, Pratt & Whitney Canada, and the Studebaker Corporation. The original pictures from the “Cyclone” manual are of moderate quality (Figure 88‑1a): Figure 88-1 R-1820, viewed from the rear The modern photo (Figure 88‑1b) reveals more details. Horsepower ranged from 700 hp to 1,500 hp depending on the model and configuration. Wright R-1820 “Cyclone” By Kimble D. McCutcheon If you were a child in the years of 1964 through 1969, your introduction to the sights and sounds of the Wright R-1820 “Cyclone” was probably due to the popular television series “Twelve O’clock High”.