United Engine Corporation (UEC) is advancing its lineup of fifth-generation fighter engines with the 177C and the more powerful “Product 177.” On December 22, 2025, UEC confirmed the Su-57 fighter’s first flight with the “Product 177” engine, marking the start of its flight test program.
“UEC and United Aircraft Corporation (UAC) specialists have commenced flight testing the ‘Product 177’ engine integrated into the Su-57 fifth-generation fighter. The aircraft was piloted by Russia’s honored test pilot Roman Kondratyev. The sortie proceeded according to the planned flight task,” the company’s press release stated.
The engine was installed on the experimental Su-57, serial number “052,” replacing the standard AL-41F engine. This aircraft previously conducted second-stage flight tests of the “Product 30” engine and a variant with a flat nozzle.
In the 177C and 177 engines, several advanced technologies have been implemented, yielding a significant performance increase over previous-generation engines. A key achievement is a 7% reduction in fuel consumption, accomplished through the synergy of multiple engineering solutions. High-temperature sections utilize heat-resistant materials and coatings, while airflow and turbine aerodynamics have been optimized.
Both engines are equipped with a digital Full Authority Digital Engine Control (FADEC) system, which manages optimal operating modes, along with an upgraded cooling system for critically stressed components. According to UEC, the combination of these technologies ensures target thrust, efficiency, and engine life for the 177C in a single configuration.
Public demonstrations in 2024 at the Zhuhai Airshow, in February 2025 in Bangalore, and at the Dubai Airshow 2025 in November, underscored the strategic positioning of the 177C/177 engines. These units are designed not only to enhance aircraft performance but also to reduce life-cycle costs.
| Parameter | 177C | 177 | ||
|---|---|---|---|---|
| Thrust (afterburner), lbf | 31,970 | 35,275 | ||
| Thrust (military power), lbf | 19,840 | 24,250 | ||
| Specific fuel consumption, lb/lbf·h | < 0.067 | < 0.067 | ||
| Design service life, hours | 6,000 | 6,000 | ||
| Time between overhauls, hours | 1,500 | 1,500 | ||
| Dry weight, lb | 3,307 | 3,417 | ||
| Note: Specifications based on UEC data at Dubai Airshow 2025 | ||||
Technical analysis highlights a high thrust-to-weight ratio, a critical parameter for fighter aircraft. Offering two engine variants provides flexibility to tailor powerplants to specific performance requirements. Both versions feature thrust-vectoring nozzles (TVN), directly enabling supermaneuverability.
Russia presented the fifth-generation 177C engine for front-line aviation at the exhibition in China
A major factor in economic efficiency is the extended design life, significantly surpassing that of previous engines. This reduces the number of engine replacements during an aircraft’s operational lifetime, lowering procurement and overhaul costs, optimizing spare parts logistics, and ultimately increasing the fleet’s average mission readiness by minimizing downtime.
The development and integration of these engines establish a foundation for further advancement of fifth-generation aircraft. In the long term, this enhances operational reliability, fleet efficiency, and maintains high levels of combat readiness and technological competitiveness.
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