The Chengdu J-20 advanced fifth-generation heavyweight air superiority fighter was unveiled on June 29, its inaugural flight featured the utilization of the new WS-15 afterburning turbofan engine in a twin configuration. This flight took place at the test airfield of the Chengdu Aircraft Industry Corporation, located near its primary aircraft plant. Remarkably, this facility stands as the sole non-U.S. site capable of producing multiple squadrons’ worth of fifth-generation fighters. Although visual confirmation of the WS-15 engines was not possible, the presence of a banner adjacent to the runway and the distinctive sound emitted by the powerplants differed from the previous WS-10C engines.
In January 2022, the WS-15 engine was initially integrated into the J-20 in a single configuration for a test flight. Within a mere 18 months, the program progressed rapidly, transitioning to flights in a twin configuration. This shift signifies a heightened level of confidence in the engine’s performance. The decision to fly with a second engine from the older, well-tested WS-10C design, which currently powers most J-20 units, provides a contingency plan for landing on the WS-10 if any performance issues arise with the WS-15.
Unlike the U.S. Air Force’s F-35 single-engine fighter, which prioritizes reduced lifetime costs at the expense of flight performance, the J-20, owing to its size, was designed to be powered by two engines, similar to the American F-22 Raptor. In December 2022, an enhanced variant called the J-20B was unveiled, featuring the integration of the new engines. Notably, this variant showcased a flatter, low-profile canopy, expected to significantly enhance the airframe’s stealth capabilities and aerodynamics. Furthermore, this modification enables better integration of the fighter’s raised spine, aligning with similar advancements in China’s other fifth-generation fighter, the FC-31.
The J-20B was reported to enter production in July 2020, while full serial production of the WS-15 engine began in March 2023. Clear images depicting the engine in flight testing were publicly released on April 5, 2023. The J-20 fighter already boasts superior endurance compared to Western fighter classes, and the WS-15 is anticipated to further extend this advantage due to its enhanced fuel efficiency. Consequently, J-20 units may engage in longer-range patrols, execute air defence duties with extended loitering capabilities, more effectively target locations in Taiwan from the less fortified eastern coast, and potentially conduct strike missions against Western facilities in Japan without excessive reliance on aerial refuelling.
The WS-15 engine is widely regarded as the most potent engine ever integrated into a twin-engine fighter. This distinction is particularly notable as the Soviet AL-41F for the MiG-1.42 fighter and the D-30F-6 for the MiG-31M interceptor were terminated following the state’s disintegration. While the F119 engine powering the F-22 currently leads with 17.5 tons of thrust, estimates place the WS-15’s thrust as high as 19-20 tons, with a thrust-to-weight ratio comparable to the F135 engine that drives the F-35. The WS-15 engine is expected to deliver significant improvements across all aspects of the J-20’s flight performance. Additionally, it is anticipated to reduce operational and lifetime costs due to lower maintenance requirements compared to the WS-10C engine. While the WS-10 engine enabled the J-20 to achieve supercruise capabilities, allowing supersonic speeds without afterburners, thus making it the world’s only fifth-generation fighter with this capability, the WS-15 engine is expected to enable even higher cruising speeds.
The J-20 and F-35 stand as the sole fighters of their generation produced and deployed at squadron-level strength. In contrast, the troubled F-22 has faced orders to terminate production and is set to commence early retirement. In March 2022, the J-20 and F-35 encountered each other for the first time, receiving confirmation of their meeting. Following this encounter, General Kenneth Wilsbach, the head of Pacific Air Forces, lauded the operational capabilities of the J-20, particularly emphasizing its commendable command and control systems. By combining the strengths of high flight performance and extensive weapons carriage, akin to the F-22, with advanced avionics features like distributed aperture systems and helmet-mounted sights reminiscent of the F-35, the J-20 surpasses both American platforms in areas where they face notable limitations.