| 词条 | Tumansky R-25 | |||||||||||||
| 释义 |
The Tumansky R-25 is a turbojet engine, which is seen as the ultimate development of Tumansky R-11. It was designed under the leadership of Sergei Alekseevich Gavrilov. Design and developmentThe Tumansky R-25 was designed as a replacement for Tumansky R-13 in MiG-21 fighters. R-25 is a two-spool axial-flow turbojet featuring a new compressor with increased overall pressure ratio and airflow, variable two-stage afterburner, and greater use of titanium. 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 {{convert|96.8|kN}} of thrust under {{convert|4000|m}} of altitude. The limit of operation is 1 minute for dogfight practice and 3 minutes for an actual wartime emergency, as further use causes the engine to overheat and potentially explode. Use of CSR 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, but the extreme thrust of CSR allowed the MiG-21bis to reach a better than 1:1 thrust-to-weight ratio for dogfight and theoretically outclimb the F-16. The R-25 engine was used on the MiG-21bis 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 for its fleet of MiG-21bis. Specifications (R-25-300){{jetspecs| |type=Afterburning turbojet |length=4,615 mm (181.7 in) |diameter=1,191 mm (46.9 in) |weight=1,212 kg (2,670 lb) |compressor=Two-spool axial compressor |combustion= |turbine= |fueltype= |oilsystem= |power= |thrust=
|compression=9.5:1 |aircon= |turbinetemp=1,040 °C (1,904 °F) |fuelcon= |specfuelcon=
|power/weight= |thrust/weight=56.5 N/kg (5.8:1), 79.9 N/kg (8.1:1) with boosted afterburner }} See also{{aircontent|see also= |related=
|similar aircraft= |lists=
|similar engines= }} References1. ^Globalsecurity.org: War in Afghanistan External links{{Commons category}}
2 : Tumansky aircraft engines|Turbojet engines 1970–1979 |
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