Su-37 Super Flanker vs Su-57 Felon

While sharing the Sukhoi lineage, the Su-37 Super Flanker and Su-57 Felon occupy entirely different positions in Russian aerospace history: one was a transient technology demonstrator that salvaged the Flanker family during the post-Soviet economic collapse, while the other is a clean-sheet attempt to break the Western monopoly on fifth-generation warfare. The Su-37 was a singular prototype designed to market upgrades for the Su-27, whereas the Su-57 is a frontline platform currently engaged in high-intensity combat operations in Ukraine.

Development and Design

The Su-37 (T10M-11) was an evolutionary peak of the fourth-generation Su-27 airframe. Its design philosophy centered on extreme agility through aerodynamic instability, utilizing foreplanes (canards) and the first application of 2D thrust-vectoring nozzles (TVC) on the AL-37FU engines. This configuration validated flight control algorithms later exported in the Su-30MKI and Su-35S. Conversely, the Su-57 prioritizes Low Observability (LO) and sensor fusion over pure kinematic performance. The Felon abandons canards for Leading Edge Vortex Controllers (LEVCONs) and incorporates internal weapons bays to reduce radar cross-section (RCS). While the Su-37 relied on external ordnance and mechanical scanning radars (N011M), the Su-57 integrates the N036 Byelka AESA radar and composite materials covering 70% of its surface area to delay detection.

Specifications and Performance

The Su-57 demonstrates the shift from raw speed to sustained energy and range. While the Su-37 achieved a higher maximum speed of 2,494 km/h compared to the Su-57's 2,135 km/h, the Felon offers superior endurance with a 3,500 km range and a service ceiling of 20,000 m, 2,000 m higher than its predecessor. Powerplant evolution is evident in the thrust figures: the Su-57’s Saturn AL-41F1 engines generate nearly double the total thrust (28,960 kgf) of the Su-37’s AL-37FU setup (15,196 kgf), granting the Felon a significantly higher thrust-to-weight ratio critical for supercruise. Although the Su-37's +15/-15 degree vertical thrust vectoring was revolutionary in 1996, the Su-57’s 3D vectoring provides yaw control, enhancing maneuverability in the post-stall regime.

Deployment and Usage

Operational history starkly divides these aircraft. The Su-37 never saw combat; the sole airframe crashed in 2002 due to structural failure, ending the program but securing export orders for Su-30 variants. The Su-57, despite a troubled production run of only 32 units, has been integrated into Russian Aerospace Forces (VKS) doctrine. Moscow deployed the Felon to Syria in 2018 for avionics trials and has utilized it in the invasion of Ukraine since 2022. Unlike the Su-37’s air show profile, the Su-57 operates cautiously in a standoff role, launching Kh-59MK2 and Kh-69 cruise missiles from Russian airspace to avoid engaging Ukrainian air defenses, confirming that the VKS values the airframe more as a sensor/shooter node than a dogfighter.

Conclusion

The Su-57 is the superior platform, rendering the Su-37 obsolete in modern network-centric warfare. The Su-37’s reliance on external stores and non-stealthy airframe would make it survivable only in permissive airspace. The Su-57, despite production bottlenecks and debates regarding its stealth capabilities relative to the F-35, provides the VKS with essential stand-off capabilities and internal carriage for hypersonic munitions like the izdeliye 810. The Su-37 succeeded as a marketing tool that funded Sukhoi's survival; the Su-57 struggles to succeed as a mass-produced replacement for the fleet that the Su-37 helped build.