Sukhoi Su-57 Su-57M

As early as 2004 Sukhoi anticipated that the Su-57 could become the basis for a family of combat aircraft for the Russian Aerospace Forces, much like the Su-27 family. Under the programme name Megapolis, the bureau is developing a variant designated Su-57M that augments the base design with improved mission systems, reliability and maintenance enhancements, electromechanical drives and the new NPO Saturn izdeliye 30, or AL-51F-1, engines. As a backup, Saturn runs the Udlinitel programme to further improve the AL-41F-1.

The formal contract was signed in 2018, although preliminary work had begun earlier. In 2020, flight testing of the improved variant was planned to begin in 2022, with serial production in the mid-2020s. The United Aircraft Corporation reported that an upgraded Su-57 made its first flight on 21 October 2022, but it is unclear whether that airframe represents a Su-57M: the second-stage engine was reportedly not mounted.

The engine is the programme's weak point. The AL-51F-1 has had a sluggish test pace and developmental difficulties, to the point that in 2025, at the Dubai Air Show, Rostec unveiled the izdeliye 177, which combines components and technology from both the AL-41F-1 and the AL-51F-1 and is proposed as an alternative to the latter; that engine, likely the result of the Udlinitel project, first flew in December 2025. In parallel, UEC Saturn has been developing since 2023 a non-axisymmetric flat nozzle whose flight testing began in late 2024, intended for both the AL-51F-1 and the izdeliye 177 and designed to fit with minimal changes to the airframe.