Mikulin M-17

The Soviets had bought examples of BMW's III and IV engines earlier in the 1920s and bought two examples of the VI engine in 1926 for evaluation. Following successful bench trials of the engine the Soviets decided to purchase a license for it. A deal was concluded in October 1927 after prolonged negotiations. The Soviets paid $50,000 and were to pay 7.5% of the price of each engine produced after the first fifty. In exchange, the German company was to inform the Soviets of all changes to the engine for a period of five years. Soviet engineers and technicians were to be trained in Germany and German technicians were to assist setting up production in the vacant factory at Rybinsk. The Soviets also hired a number of German skilled workers to work at Factory No. 26 in Rybinsk, mostly those with communist sympathies.[2]

The need to refurbish the factory greatly delayed Soviet production, even though the more complex components, including all electrical equipment, were initially imported from Germany. Soviet changes to the design and production quality issues meant that the Soviet-built engines were some 31 kg (68 lb) heavier and produced less power than the original engine. The first M-17s, as the engines were designated by the Soviets, were not produced until spring of 1930, but were not accepted for service until an engine passed its service tests on 15 August 1930. The M-17 was the most powerful engine available to the Soviet aircraft industry and it was in high demand, so much that Factory No. 24 in Moscow also began to build the M-17. 165 engines were produced in 1930 at Rybinsk and Factory No. 24 had managed to build its first three engines by June 1930.[3]

Unfortunately, the engines built by the Moscow factory were of very poor quality because the management there had made unauthorized changes to simplify production. These had a compression ratio of only 6.15:1 rather than the specified 6.3:1 and they could produce only 615–630 hp (459–470 kW) instead of the 680 hp (510 kW) of the Rybinsk engines. The Moscow engines, of which only thirty were made, were reclassified as training engines and bought for a reduced price. In the meantime production of the M-17 in Moscow had been cancelled in favor of the M-15. Production of engines at Rybinsk had been steadily increasing, 679 being built in 1931 and 5662 in 1934.[4]

Around 1935, development of a version suitable for tanks was begun. This was called the M-17T and 7951 were built from 1936 to 1939. The advent of the Mikulin AM-34, which was intended as a replacement for the M-17, reduced the need for aircraft models and the Rybinsk factory was producing three tank engines for every aircraft engine by 1936, although production of the aircraft variants continued until the end of 1939 to replace worn-out engines on older aircraft. The M-17L was a version of the M-17T used to power the T-35 heavy tank and was the last model placed into production, 530 being built from 1940 to 1941. A number of engines of various models were assembled from spare parts during World War II, but no records are available as to numbers and types.[5]

Data from

General characteristics

• Type: 12-cylinder 60° Vee aircraft piston engine
• Bore: 160mm (6.30 in)
• Stroke: 190/199 mm (7.48/7.83 in) different between right and left cylinder bank due to articulated connecting rods.
• Displacement: 46.9 L (2,864 cuin)
• Length: 1,810mm (71.26 in)
• Width: 859mm (33.82 in)
• Height: 1,103mm (43.43 in)
• Dry weight: 540-553 kg (1,190-1,219lb)

Components

• Fuel system: K-17 Carburetor
• Cooling system: Liquid-cooled

Performance

• Power output: 680–730 hp (510–540 kW)
• Compression ratio: 6.0:1 or 7.3:1

Related development

• BMW VI
• Mikulin AM-34

Related lists

• List of aircraft engines