‘F-35 rival’: China’s 5th gen J-31B stealth jet readies for combat role

The J-31B’s side weapon bays indicate it has a payload capacity comparable to heavy fighters, excelling in design and engine performance. It can carry at least two missiles in its side bays and four PL-12 missiles in its main bay, similar to the J-20.

If equipped with ground or anti-ship weapons, the J-31B becomes a multi-role fifth-generation fighter with stealth, situational awareness, and all-domain offensive capabilities.

Beijing-based military analyst Fu Qianshao noted that the fighter, developed by SAC over more than a decade, is now deemed operational. “The transition from FC-31 to J-31 signifies its readiness for military service and official designation,” Fu stated, the South China Morning Post reports.

Advanced single-door weapon bay design

The J-31B’s side weapon bay uses a single-door design, similar to China’s J-20 stealth fighter. In 2018, the J-20 showcased its full weapon load at an air show, opening both its main and side weapon bays. 

Unlike the F-22’s double-door design, the J-20’s single-door bay allows the door to close after missile deployment, reducing the impact on stealth and aerodynamics. This design difference affects the air combat modes of the F-22 and J-20.

Chinese military expert Song Xinzhi, speaking on a CCTV program, explained that opening a stealth fighter’s weapon bay compromises its stealth by increasing radar detectability. The J-20’s unique design aims to minimize this drawback as effectively as possible.

Chinese air force enhances pilot training for J-20 fighter jets

Since its maiden flight in 2012, designed as a fifth-generation stealth fighter for the People’s Liberation Army (PLA) and potentially for export markets, the warplane has undergone extensive development and testing.

It debuted at the 2014 Zhuhai Airshow and is positioned as China’s counterpart to Lockheed Martin’s fifth-generation F-35 Lightning II. Once in service, it would mark China as the second country, after the United States with the F-22 Raptor and F-35 Lightning II, to operate two types of stealth aircraft.

During the early stages of FC-31’s development in 2013, chief designer Sun Cong expressed hope to state media that a variant of the jet would join the PLA Navy aircraft carriers following the fourth-generation J-15, also developed by SAC and currently China’s sole active carrier-based fighter jet.

In 2015, Chinese state media reported that the J-31 could support J-20 fighter jets in aerial combat and potentially serve alongside the J-15 as a carrier-based aircraft.