Klimov M-103

M-103
Klimov M-103 engine recovered from Tupolev SB wreck
Type	V12 inline engine
Manufacturer	Klimov
First run	October 1936
Number built	11,681
Developed from	Klimov M-100
Developed into	Klimov M-105

The Klimov M-103 is a V12 liquid-cooled piston aircraft engine used by Soviet aircraft during World War II.

The M-103 was a further development of the Klimov M-100 engine that was itself a licensed copy of the French Hispano-Suiza 12Ybrs. It differed from both engines in a number of aspects such as increased compression ratio, increased supercharger ratio, increased rpm's, strengthened cylinder blocks, a new crankshaft, a more aggressive camshaft, and flat bottomed cylinders. Developed in 1936 it was ready for testing in October 1936. The first two models failed testing due to cracked cylinder blocks and the engine was resubmitted for testing in 1937. After passing its trials it was cleared for production in 1938 and 11,681 were produced until 1942 at its factory in Rybinsk. The M-103 was followed by the M-105.

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Wikipedia