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Tumansky R-15


The R-15-300 axial flow, single shaft turbojet with an afterburner was designed at OKB-300 design bureau led by Sergei Tumansky in the late 1950s. The engine was originally designed to be used in the Tupolev Tu-121 high-altitude high-speed cruise missile. Due to lacking Soviet resources and funding the engine casing was mainly steel, and in areas exposed to high levels of heat, 30 micrometre silver-plated steel. At the time, the USSR did not have the resources to exploit metals such as titanium, or other composite alloys, which could have greatly reduced the engine's weight. The Tu-121 effort was later canceled, but its basic design was re-used to create the Tupolev Tu-123 reconnaissance drone.

At dry thrust the engine could produce 7,500 kilograms force (73.5 kN, 16,500 lbf); with afterburner the output is 11,200 kilograms force (110 kN, 24,700 lbf). This allowed speeds of up to mach 3.2 in the Mikoyan-Gurevich MiG-25 (which used two engines). However, at speeds above mach 3, the force of the engine sucking fuel through the pumps overwhelmed the pumps' ability to limit the flow. At this point, the engines effectively became ramjets, as air began to bypass the low pressure compressors, accelerating out of control until the pilot could regain throttle control through using firewalls or compressor stall, or the tanks ran dry. The engine also suffered from huge fuel consumption issues, especially at low altitudes. The engines did give excellent performance at high altitude though, with good fuel consumption and speeds at 80,000 feet (24,000 m), which was considerably better than any Western aircraft at the time (early 1960s). The MiG-25 was able to supercruise. The R-15BD-300 was known for ease of maintenance, performance, and good monitoring systems for both pilots and engineers.


R-15-300: Original version. Used in Tupolev Tu-123 Yastreb drone.


R-15B-300: Electronic engine controls (the first for the Soviet engine). and modifications to increase life span. Original engine for the MiG-25P, MiG-25R and variants. Life expectancy 150 hours.  

R-15BD-300: Improved and more powerful version for MiG-25PD and MiG-25PDS. Life expectancy increased to 1000 hours.

R-15BF2-300: Uprated version. Used in Ye-266M high-performance MiG-25M prototype. MiG-25M aircraft was never put into production

The only aircraft that uses the R-15-300 is the MiG-25. These engines made it the fastest (clocked at Mach 3.2) fighter aircraft ever put into production.
Prototypes were also used for Mikoyan-Gurevich Ye-150 family of single-engine interceptor prototypes.
Tupolev Tu-123 drone


Type: Afterburning turbojet
Length: 6,264 mm (246.6 in)
Diameter: 1,512 mm (59.5 in)
Dry weight: 2,454 kg (5,410 lb)
Compressor: 5-stage axial compressor
Turbine: single-stage turbine
Maximum thrust:
73.5 kN (16,523 lbf) military power
100.1 kN (22,503 lbf) with afterburner
Overall pressure ratio: 4.75:1
Turbine inlet temperature: 942 °C (1,727 °F)
Specific fuel consumption:
127 kg/(h·kN) (1.25 lb/(h·lbf)) at idle
275 kg/(h·kN) (2.70 lb/(h·lbf)) with afterburner






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