Russian Salut Continues To Upgrade AL-31F

According to the Salut Gas Turbine Research and Production Centre’s Director General Vladislav Masalov, the company manufactured about a hundred AL-31F turbofans in several variants in 2011. Over 75% of them, in the AL-31FN version in the first place, were exported. The rest were made for the Russian Defence Ministry. To fit the aircraft in service with the Russian Air Force, the company has for several years supplied AL-31F Series 42 engines upgraded by the in-house design bureau and known as AL-31F-M1.

The AL-31F-M1 passed its official trials in 2006 and has been ordered by the Defence Ministry since 2007 to equip Sukhoi Su-27SM fighters. Last year, Salut shipped another batch of engines of the type, which were used for fitting the Su-27SM(3) fighters delivered to RusAF under the contract signed in 2009. A decision in principle was taken to fit the RusAF-ordered Sukhoi Su-34 bombers with Salut-built AL-31F Series 42s. Unlike the baseline AL-31F, the upgraded engine has an advanced enlarged-diameter fan (924 mm) and an automatic control system with a digital integrated governor, which has increased the thrust up to 13,500 kgf and extended the service life.

AL-31FN for J-10

The next stage of the Salut-conducted upgrade is to become the AL-31F-M2 engine, which thrust in special mode will increase to 14,500 kgf and the service life to 3,000 h or more.

Early this year, Salut hosted a meeting of the scientific and technical board attended by personnel of the Sukhoi design bureau, Lyulka scientific and technical centre (an affiliate of NPO Saturn JSC), United Aircraft Corporation and United Engine Corporation. The board met to consider the results produced by the development work on upgrade the second-stage AL-31F (AL-31F-M2). All work pertinent to the second stage of the engine’s upgrade is on schedule. To date, the engine has completed its special bench tests in Central Institute of Aviation Motors thermal vacuum chamber, which have proven the feasibility of a static thrust of 14,500 kgf and the manufacturer’s performance ratings. The upgraded engine has a 9% increase in thrust in flight modes over the AL-31F-M1.

“The upgrade of the AL-31F engine does not involve modifying its dimensions and is aimed at retaining the feasibility of re-engining the whole of the Su-27 aircraft fleet without extra modifications to the airframe or engine nacelles”, Salut General Designer Gennady Skirdov said.

Until year-end 2012, the special bench and endurance test programme is to be completed and the special flight test programme is to begin. The flight trials of the AL-31F-M2 are supposed to involve using a Su-27SM the Sukhoi company may provide or Gromov LII’s Su-27 flying testbed used for testing the AL-31F-M1.

According to Salut Director General Vladislav Masalov, series deliveries of upgraded engines may well begin in 2013. “The AL-31F-M2 engine is an inexpensive option for re-engining the Su-27, Su-30 and Su-34 aircraft fleets in service with the Russian Air Force and for export”, the Salut Director General said. To meet the requirements specification in a fuller manner, the Su-27SM and Su-34 need an enhanced-thrust reduced-fuel-burn engine. The AL-31F-M2 is just the thing, as representatives of the Sukhoi design bureau have agreed. To cap it all, replacing the AL-31F with it necessitates no modifications to the aircraft and can be performed in the field.


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