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, an ...
engine, which is seen as the ultimate development of
Tumansky R-11
The Tumansky R-11 (initially AM-11) was 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
Tumansky R-13
The Tumansky R-13 is a Soviet turbojet engine designed by Sergei Alekseevich Gavrilov.
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 ...
in
MiG-21
The Mikoyan-Gurevich MiG-21 (russian: Микоян и Гуревич МиГ-21; NATO reporting name: Fishbed) is a supersonic jet fighter and interceptor aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. Its nickn ...
fighters. 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 featuring a new
compressor with increased
overall pressure ratio
In aeronautical engineering, overall pressure ratio, or overall compression ratio, is the ratio of the stagnation pressure as measured at the front and rear of the compressor of a gas turbine engine. The terms ''compression ratio'' and ''pressure ...
and airflow, variable two-stage afterburner, and greater use of
titanium
Titanium is a chemical element with the Symbol (chemistry), 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, resista ...
.
The R-25 jet engine's specialty was the addition of a second fuel pump in the afterburning stage. Activating the ЧР (rus. "чрезвычайный режим" - emergency mode) booster feature allows the engine to develop of thrust under of altitude. The limit of operation is 2 minutes in practice and in war, as further use causes the engine to overheat and potentially explode. Use of
EPR requires engine take-out inspection upon landing and every minute of its use counts as one full hour of engine runtime on the logbook. This further shortens the already limited cycle time of Soviet made engines between industrial-level overhauls and adds great cost.
The R-25 engine was used on the
MiG-21
The Mikoyan-Gurevich MiG-21 (russian: Микоян и Гуревич МиГ-21; NATO reporting name: Fishbed) is a supersonic jet fighter and interceptor aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. Its nickn ...
bis and the
Sukhoi Su-15bis. 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 (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
for its fleet of
MiG-21
The Mikoyan-Gurevich MiG-21 (russian: Микоян и Гуревич МиГ-21; NATO reporting name: Fishbed) is a supersonic jet fighter and interceptor aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. Its nickn ...
bis.
Specifications (R-25-300)
See also
References
External links
R-25 on LeteckeMotory.cz(cs)
{{Tumansky aeroengines
Tumansky aircraft engines
1970s turbojet engines