All future Su-57 fighters delivered to the Russian Air Force by the United Aircraft Corporation (UAC) will be powered by the advanced and more powerful Stage 2 engine, also called Izdeliye 30.
The supercruise-capable engine can take the jet to supersonic speeds without engaging the afterburner, reducing heat signature, enhancing fuel efficiency and thrust, and cutting maintenance and life-cycle costs.
The Su-57 flies on the NPO Saturn Product 117 engine, derived from the Su-35’s afterburning AL-41F-1S turbofans. The new engine, the AL-51F-1 turbofan, puts the Su-57 firmly in the Generation 5 category.
Indeed, Russian officials insist that even with the previous engine, the Su-57 was more than capable and met all performance criteria.
The S-57 was used in the ongoing war to destroy Ukrainian radars, and some batches in the fleet also received artificial intelligence (AI), which enabled pilot interface, communications, and aircraft system management technologies. The announcement of the new engine marks another step in the aircraft’s steady operationalization.
‘New Engines For The Latest & Future Batch’
According to TASS, which quoted “two high-ranking sources,” all Su-57s transferred to the Russian Aerospace Forces (VKS) in 2024 will receive second-stage engines. “The second stage’s engine has been tested and is ready for operation,” said the sources.
This engine will be installed on the subsequent batch of Su-57 jets delivered to the VKS/RuAF in 2024. Ten Su-57s that the VKS received from the Komsomolsk-on-Amur Aircraft plant in 2023 were also powered by Stage 2 Izdeliye 30 engines, disclosed earlier.
In other words, the Stage 2/Izdeliye 30/AL-51F-1 would be standard features on any Su-57 delivered to the RuAF from here onwards.
‘No Need to Install New Engines On Su-57s Delivered So Far’
However, this does not mean the Su-57s in service will be retrofitted with the new power plants. Russian air force planners and defense industry officials perceive the effort as highly tedious and costly.
Even if the pre-2023 Su-57 airframes would be flexible and compatible enough to assimilate the newer engines with little to no changes, the Russian official indicated technical, tactical, and operational reasons for not having the new ones. The primary reason, though, is that such an effort is unnecessary.
“There are no plans to replace the first-stage engines on the Su-57s already transferred to the Aerospace Forces with new engines (as) even with the first-stage engine,” the official said.
The Russians have long anticipated a future war with the US and NATO. Any absence of Su-57 units from the existing fleet will severely upset its operational calculations.
Why Russia Can’t Afford To Reduce Su-57 Numbers
The RuAF is expected to have 76 Su-57 fighters by 2027. This is stated in the State Armament Program and the contract signed between the United Aircraft Corporation (UAC) and the RuMoD during the 2019 iteration of the Armiya 2019 exhibition.
Based on reports in Russian media from 2018 until now that quoted officials like Rostec’s First Deputy Director General Vladimir Artyakov and CEO Sergey Chemezov, the number of Su-57s in service can be assumed to be at least 20.
However, going by standard practices in air forces, not all of them will be operationally available all the time. Some will be used to train new pilots, develop new technologies, and practice operational procedures and tactics.
For instance, it was operationally used in a June 2022 Suppression of Enemy Air Defense/Destruction of Enemy Air Defense (SEAD/DEAD) mission.
Four Su-57s were “linked and integrated into a single information network through automatic communication systems, data transmission, navigation and real-time identification.”
The official added that the “low radar signature of the Su-57 was confirmed,” which means the Su-57s are still mainly being tested for developing the full range of tactics, operational concepts, and standard operating procedures (SOP).
A significant part of the tactics would be integrating the Su-57 with its loyal wingman, the S-70 Okhotnik drone, other fighters like the Su-35, Su-30SM, and the A-50U AWACS, and establishing the launching sequences of missiles. A EurAsian Times report in September said the Su-57s are awaiting the arrival of the 300-kilometer range air-to-air missile (AAM), which was concluded to be the RVV-BD/R-37M.
Training and experimental needs will tie down a significant number of the present Su-57 fleet, and an engine retrofitting project will further reduce that figure. This also dilutes the deterrence value of the RuAF before NATO air forces, particularly when the F-16s are expected to arrive in 2024.
Thus, the Russian decision was to install the new engines on the 2023 and the post-2023 batch. Moreover, even with the present AL-41F-1S turbofan, “the Su-57 surpasses the American F-35 in its characteristics,” the official added.
Characteristics Of New Engine
The Stage 2 engine features a serrated exhaust nozzle, also called a chevron nozzle, which improves thrust efficiency, stability, maneuverability, and performance while reducing engine noise.
They also go a long way in reducing the aircraft’s infrared (IR) and radar signatures. The jagged serrations disrupt the radar waves that touch the plane and prevent them from returning to the radar emitter.
By altering the exhaust plume’s temperature distribution and shape, serrated nozzles can make the fighter harder to detect for air-to-air missiles with an IR seeker in their terminal guidance mode. IR seekers are highly effective during heavy electronic warfare (EW) scenarios, especially during clashes between conventional air forces.
Jets would employ their onboard jammers to disable missiles with radar seekers and electromagnetic emissions. They are hard to jam when homing in because they rely on a jet’s heat signatures. An altered IR characteristic with serrated nozzles helps achieve this goal.
The Stage 2 engine reportedly offers 11 tons (107.9 kN) dry and 17 tons (167 kN) in the afterburner. It will allow the Su-57 to supercruise between Mach 1.5 and Mach 1.6. The new engine also has a Full Authority Digital Electronic Control (FADEC) system.
This helps “to set arbitrary engine control laws and flexibly adapt them to different conditions,” according to the general designer of the A. Lyulka Design Bureau, Evgeniy Maruchkov.
“This significantly speeds up setup time and increases system reliability, allowing you to implement changes quickly. In old control systems, any change was a non-trivial task,” Maruchkov explained.