Tumansky M-87
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Tumansky M-87 was a Soviet air-cooled aircraft radial engine.
[edit] Development
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.[1] The M-87 was created to further increase the power output. Cylinders and pistons were revised to increase the compression ratio and the supercharger was redesigned. The resulting engine had better high-altitude performance and entered production in 1938. However, the engine proved unreliable and suffered from failure of gears in the reduction gearbox.[1] Later the M-88 was designed to address the shortcomings of the M-87. At first the M-88 wasn't a success, but the designers persisted and the M-88 was made into a reliable and widely produced engine. The M-87 was used in Ilyushin Il-4 and Sukhoi Su-2 bombers, and the Polikarpov I-180 fighter.
In hindsight the Tumansky family of engines developed from Gnome-Rhône 9K and Gnome-Rhône 14K, were far less successful than the Shvetsov family of engines developed from the Wright R-1820.
[edit] Specifications (M-87)
General characteristics
- Type: two-row 14-cylinder air-cooled supercharged radial engine
- Bore: 146mm (5.75 in)
- Stroke: 156mm (6.5 in)
- Displacement: 38.72 l (2,363 in³)
- Dry weight: 640 kg (1,140 lb)
Components
- Supercharger: Centrifugal type supercharger
- Cooling system: air
Performance
- Power output: 950 hp (710 kW) at 2,250 rpm for takeoff and at 4 500 m (14,765 ft)
- Specific power: 18.4 kW/l (0.4 hp/in³)
- Compression ratio: 6.1:1
- Power-to-weight ratio: 1.1 kW/kg (0.8 hp/lb)
