The Shvetsov M-11 is a five-cylinder air-cooled radial aircraft engine produced in the Soviet Union between 1923 and 1952. Design and development The Shvetsov M-11 was designed under a 1923 competition in the Soviet Union for a new engine to power trainer aircraft. It is a single-row five-cylinder air-cooled radial piston engine with aluminum cylinder heads. Like the American Kinner B-5 5-cylinder radial of similar size, the M-11 had individual camshafts for each cylinder, operating the pushrods, rather than a single central cam ring. The initial versions of the M-11 suffered from a short service life of only 50 hours. The basic M-11 engine had a power output of 100 hp (73 kW), the newer M-11D variant was higher at 125 hp (92 kW). The ultimate version, M-11FR, introduced in 1946, increased power output to 160 hp at 1,900 rpm on takeoff and 140 hp at cruise and had provisions for a variable-pitch propeller, accessory drive (for vacuum pumps, compressors, generators, etc.) and featured a floatless carburetor. Variants Data from: M-100 Designation of prototype and initial designs. M-11Initial production version at , compression ratio 5:1 M-11a / M-11/A / M-11B / M-11D / M-11ECompression ratio 6:1 - / M-11F / M-11FM M-11FRCompression ratio 5.5:1 - / M-11FR-1Compression ratio 5.5:1 - / M-11FN M-11G / M-11ICompression ratio 5.5:1 - / M-11K / M-11L / M-11M M-11V / M-11Ya:A projected development of the M-11 at GAZ-41. The prototype was run but results were unsatisfactory, re-designated M-12 M-11YeDeveloped by Okromechko Further developments 3M-11 An alternative designation for the M-50 three cylinder derivative of the M-11 M-12 A development of the M-11 by M.A. Kossov, un-related to the NAMI-100, which had been earlier designated M-12. M-12 (M-11Ya)A projected development of the M-11 at GAZ-41. The prototype was run but results were unsatisfactory, re-designated from M-11Ya M-13 (M-13K) A 1944 development by M.A. Kossov to be assembled from various M-11 variants M-13 In parallel with the M-13K, E.V. Urmin at GAZ-41 mated cylinders from the M-11D with new crankshaft and crankcase M-13 A later M-13 was created by I.A. Muzhilov at OKB-41 in 1946. Despite passing state acceptance test in June 1948, this engine was not put into production. M-48A 7-cylinder further development at GAZ-29 M-49A 9-cylinder further development at GAZ-29 / M-50A 3-cylinder further development at GAZ-29 M-51A 5-cylinder further development at GAZ-29 / MG-11Development of the M-51 at the NIIGVF (Nauchno-Issledovatel'skiy Institut Grazdahnskovo