The Tumansky R-25 is a

turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...

engine, which is seen as the ultimate development of

Tumansky R-11 The Tumansky R-11 (initially AM-11) is a Soviet Cold War-era turbojet engine. Design and development The Tumansky R-11 was developed by A.A. Mikulin, Sergei Tumansky, and B.S. Stechkin as a twin-spool axial-flow high-altitude non-afterburni ...

. It was designed under the leadership of Sergei Alekseevich Gavrilov.

Design and development

The Tumansky R-25 was designed as a replacement for the

Tumansky R-13 The Tumansky R-13 is a Soviet turbojet engine designed by . Design and development The Tumansky R-13 is a development of the successful Tumansky R-11 engine. It is a two-spool axial-flow turbojet featuring a new five-stage high-pressure compress ...

MiG-21 The Mikoyan-Gurevich MiG-21 (; NATO reporting name: Fishbed) is a supersonic jet aircraft, jet fighter aircraft, fighter and interceptor aircraft, designed by the Mikoyan, Mikoyan-Gurevich OKB, Design Bureau in the Soviet Union. Its nicknames in ...

fighters. The R-25 is a two-spool

axial-flow An axial compressor is a gas compressor that can continuously pressurize gases. It is a rotating, airfoil-based compressor in which the gas or working fluid principally flows parallel to the axis of rotation, or axially. This differs from other ...

turbojet with a new

compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Many compressors can be staged, that is, the gas is compressed several times in steps o ...

with increased

overall pressure ratio In aeronautical engineering, overall pressure ratio, or overall compression ratio, is the amount of times the pressure increases due to ram compression and the work done by the compressor stages. The compressor pressure ratio is the ratio of the ...

and airflow, variable two-stage afterburner, and greater use of

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

. An unusual addition to the R-25 was an emergency mode thrust boost which increased the compressor speed to 106% and also increased the afterburner fuel flow with the addition of a second afterburner fuel pump. Thrust was increased to below an altitude of . The time limit for its use was 1 minute during training and 2 minutes in wartime, as further use caused the engine to overheat and be irreparably damaged. Use of this WEP required the engine to be removed on landing for inspection. Use of WEP shortened the already limited time between overhaul typical of Soviet-made engines of that era compared to Western engines. The R-25 engine was used on the

bis and the

Sukhoi Su-15 The Sukhoi Su-15 (NATO reporting name: Flagon) is a twinjet supersonic interceptor aircraft developed by the Soviet Union. It entered service in 1965 and remained one of the front-line designs into the 1990s. The Su-15 was designed to replace t ...

bis. A total of 3,200 R-25 were built between 1971 and 1975. The engine was also built under license by HAL in

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

for its fleet of

bis.

Specifications (R-25-300)

References

External links

R-25 on LeteckeMotory.cz
(cs) {{Tumansky aeroengines Tumansky aircraft engines 1970s turbojet engines

Design and development

Specifications (R-25-300)

See also

References

External links