Russia has for the first time flown a Su-57 fighter with the new Product 177 engine, according to Rostec’s press service.
The Product 177 engine worked normally and reliably during the first flight, reported the General Designer–Director of the A. Lyulka Design Bureau, a branch of PJSC UEC-UMPO of the United Engine Corporation, Evgeny Marchukov.
“The first test flight marked the beginning of joint work with colleagues from the UAC for flight tests of the Su-57 with the latest engine. During the flight, the new engine worked normally and showed reliable operation as part of the Su-57 aircraft,” the Rostec press service quoted Marchukov as saying.
According to Marchukov, the Product 177 engine has significantly improved technical characteristics compared to the power plants of the previous generation. The engine made it possible to incorporate the latest technologies, materials, and innovative design solutions.
The Product 177 has been created by UEC for use in fifth-generation aviation systems. It features a maximum thrust of 16,000 kilograms-force (kgf). Additionally, it has lower fuel consumption across all flight modes and a longer service life.
What Happened to the AL-51F Engine?
Current production Su-57 fighters are widely reported to be powered by AL-51F engines.
The AL-51F1, also known as Izdeliye 30 (Product 30), is a two-shaft low-bypass afterburning turbofan engine with a dry thrust of 108 kN and a maximum afterburner thrust of 167 kN.
The engine was developed by UEC-Saturn for the second-stage production of Su-57 fighters. First-stage production aircraft feature Product 117, also known as the AL-41F1 engine.
AL-51F First Flight
On December 5, 2017, the T-50 flew for the first time powered by Stage 2 Product 30 engines. The flight was performed by Hero of the Russian Federation and chief pilot of PJSC “Sukhoi Company” (as part of the UAC), Sergei Bogdan. The flight duration was 17 minutes and was completed in accordance with the conditions of the flight assignment.
Photos and video of the flight showed the Product 30 installed in the No. 1, or port-side, engine position, with a Product 117 engine remaining on the starboard side. The Product 30 features a serrated engine nozzle, compared to the flat nozzle on the Product 117.
The flight test was conducted by the second Su-57 aircraft prototype, also known as T-50-2.
In 2024, TASS reported, quoting sources, that 10 Su-57 fighters delivered to the RuAF in 2023 were powered by Stage 2 Izdeliye 30 engines. All Su-57 aircraft to be delivered in 2024 would feature the Stage 2 engine.
On December 11, 2024, an experimental Su-57 fighter equipped with the latest AL-51F1 turbofan engine, featuring a shaped stealth nozzle and thrust vector control, was showcased in the trailer for the documentary Lords of the Skies, which aired on Russia’s Channel One.
Product 177 5th-Gen Engine
Rostec pitches the Product 177 as a fifth-generation aeroengine.
Under Rostec classification, a fifth-generation engine features a turbine inlet temperature of 1,750 K, 3D cooling techniques, advanced superalloys, and ceramic coatings.
A fourth-generation engine features a turbine inlet temperature of ~1,600 K, single-crystal turbine blades, and advanced coatings (thermal barrier coatings—TBCs).
The Product 177 engine was possibly developed to replace the AL-51F1 / Product 30 engine, incorporating technological improvements since the initial flight of the Product 30 engine on a Su-57 in 2017.
If so, it is a more advanced variant of the AL-51F engine, with higher thrust and improved fuel efficiency.
Based on technical disclosures such as thrust rating, the Product 177 engine is a closely related Product 30 variant and is dimensionally identical to the AL-51F engine.
Product 177 may be an alternative powerplant for the export variant of the Su-57 fighter, with some of the advanced features of the AL-51F1 held back.
Over the past year or so, Rostec has pitched its Product 177S engine at airshows for export. (I dwell on the Product 177S in detail below.)
Notably, on December 22, the UAC announced that it is expanding its production capacity to increase the supply of Su-57 fighters to Russian troops and promote these aircraft for export.
“United Aircraft Corporation is currently implementing a program to expand production capacity. This will increase the volume of deliveries of the fighter to the troops, as well as actively offer the Su-57 in the export version for foreign customers,” the report says.
Under the circumstances, an alternative engine could be required to meet additional engine requirements and safeguard certain critical technologies.
Product 177S Engine
The Product 177S is likely a smaller, lower-thrust variant of the Product 177 engine developed exclusively for the export market.
UEC first displayed the Product 177S at the Dubai Airshow 2025 as a fifth-generation engine superior to foreign counterparts in both tactical and technical characteristics and capable of use on existing and future aircraft.
The 177S provides up to 14.5 tons of thrust, while its service life is three times that of the previous generation—that is, the engine’s service life is significantly increased.
The 177S provides more thrust than the AL-31F/FP fitted on Su-family aircraft, but has identical dimensions. It can replace AL-31F/FP engines fitted on Su-family aircraft without any modifications.
The engine has a service life of 6,000 hours. It can be operated at a thrust level above its rated maximum by sacrificing some engine service life.
Higher engine thrust facilitates greater electrical power generation for the operation of additional electronic systems. It also allows the aircraft to perform more complex aerobatic maneuvers.
Fuel consumption across all flight modes is 7% lower, reducing operating costs and increasing flight range.
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Conclusion
The announced increase in production of the Su-57 and the development of an alternative engine would make the Su-57 an even more attractive proposition than before for countries like India, which is interested in acquiring three to four squadrons of an interim stealth fighter to plug the operational capability gap until the start of serial production of the AMCA fighter.
If the MoD were to acquire the Su-57 with Product 177 engines, it could also acquire and locally manufacture Product 177S engines for its Su-30MKI upgrade program. The commonality between the two engines would make maintenance much easier.
- Vijainder K Thakur is a retired IAF Jaguar pilot, author, software architect, entrepreneur, and military analyst.
- This is an Opinion Article. Views personal of the Author
- Follow the author @vkthakur
