Tumansky M-87

The Tumansky M-87 was a Soviet air-cooled aircraft radial engine that was developed in the late 1930s.

In 1934, USSR licensed the French Gnome-Rhone 14K aircraft engine producing 800 hp (595 kW), which entered production as the M-85.

[1] The engine was subsequently modified to M-86 which produced 960 hp (715 kW) at takeoff thanks to increased supercharging and a higher compression ratio.

However, the engine proved unreliable and suffered from failure of gears in the reduction gearbox.

At first the M-88 was not a success, but the designers persisted, and the M-88 was made into a reliable and widely produced engine.