China has recently unveiled two new stealth fighter prototypes, each incorporating broad-spectrum stealth—a cutting-edge feature typically associated with sixth-generation aircraft.
Broad-Spectrum Stealth
Broad-spectrum stealth refers to the ability to minimize radar detectability across a wide range of frequencies in the electromagnetic spectrum. Traditional stealth aircraft, such as fifth-generation fighters, are primarily optimized to evade detection by high-frequency (centimetric) radars, commonly used in fire-control and targeting systems.
However, broad-spectrum stealth extends this capability to counter low-frequency (metric, decimetric) radars, such as VHF and UHF bands, which are increasingly used in modern air defense systems to detect conventional stealth designs.
Until now, broad-spectrum stealth technology had only been implemented in strategic bombers like the B-2 Spirit and the upcoming B-21 Raider—both designed for deep-penetration missions in heavily defended airspace. China’s move to integrate this advanced stealth capability into fighter aircraft marks a significant leap forward in military aviation.
The introduction of broad-spectrum stealth fighters positions China ahead in the global stealth race, potentially leaving countries like India trailing by decades in terms of technological advancement.
Fifth-generation fighters, such as the J-35, J-20, F-22, and F-35, feature aerodynamic surfaces on the rear fuselage for control and stability. The tail surfaces reflect metric and decimetric radar waves, compromising stealth. Aircraft designers attempt to minimize radar reflections by angling the tail surfaces.
The F-22 Raptor is shaped to be highly stealthy against centimetric wave radars but less so against metric and decimetric radars. The F-35 Lightning-2 is claimed to have better multispectral radar stealth than the F-22.
The tailless delta planforms of the new Chinese fighters give them the highest possible multispectral radar stealth.
Chengdu Aircraft Corporation (CAC) Design
The larger of the two fighters unveiled by China is believed to have been designed by Chengdu Aircraft Corporation (CAC), which had earlier developed the J-20 stealth multi-role fighter. There are reports that the fighter has reportedly been designated J-36. (We will use this nomenclature for convenience.)
The J-36 appears to be similar in length to the J-20. However, its tailless delta-wing planform makes it far more voluminous than the J-20, allowing it to carry a larger payload – fuel and weapons. As a result, the aircraft likely has very good endurance and strike capability.
Interestingly, the J-36 is powered by three engines – two in traditional configuration with intakes on either side of the fuselage and the third, positioned on top of the fuselage above the wings.
The exhausts of all three engines are shielded from ground-based radar by the fuselage-wing planform. The arrangement gives the design all aspects of stealth – the aircraft is hard to detect no matter where the ground radar is positioned – front, side, or rear.
It has been speculated that the J-36 design could potentially evolve into a regional stealth bomber or a multi-role fighter with significant air-to-air and ground attack capabilities.
Leveraging its multi-spectral radar stealth, the aircraft could enter and loiter in Indian airspace undetected for long periods, posing a severe threat.
One plausible reason for developing a three-engined fighter bomber could be the difficulties associated with designing a new, higher-thrust turbofan engine capable of powering a platform heavier than the J-20 while relying on just two engines.
SAC (Shenyang Aircraft Corporation) Design
The smaller of the two new fighters has likely been developed by SAC (Shenyang Aircraft Corporation), which developed the J-35. The aircraft features a more traditional twin-engine setup. All observations and analyses of the aircraft are based on distant images.
A tailless aerodynamic design is characterized by sluggish maneuverability. The larger the aircraft, the more sluggish its maneuverability would likely be.
It’s possible to improve maneuverability to some extent using vectored thrust engines. It’s not known whether the aircraft features thrust vectoring.
The smaller size of the SAC design suggests it is geared more towards air superiority or could serve as a versatile fighter with both air-to-air and air-to-ground capabilities. Its smaller size might allow for better agility and potentially lower radar cross-section, making it suitable for carrier-based operations or as a complementary platform to the larger Chengdu design.
Testbeds Or Prototypes?
It remains to be seen whether the two new stealth fighters are technology development test beds or prototypes of fighters that China intends to field in the near future.
The defining capabilities of sixth-generation fighters go well beyond broad-spectrum radar stealth. They additionally include
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Optional Manning, depending on the nature of the mission
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Next-Generation Power Plants
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Directed Energy Weapons.
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Unified electronic warfare system
Optional Manning would allow the aircraft to fly missions in highly contested airspace without fear of loss of life. Missions such as suppression of enemy air defenses (SEAD) and attacks on high-value surface targets entail high risks even for stealth fighters because Low Observability (LO) is never absolute.
Next-generation turbine-based power plants will feature enhanced electrical power generation capability to power sensors, communications systems, directed energy weapons, actuation systems, and accessories, as well as the usual array of avionics.
Next-generation fighters will feature lasers powerful enough to burn the seeker of an air defense (AD) or air-to-air missile. Conceivably, they could be powerful enough to attack fragile ground targets
Unified Electronic Warfare System (UEWS) will serve as a radar, an electronic warfare system, a data transmission system and as communications equipment. Additionally, it will function as a navigation system and as an IFF transponder
Only time will tell whether the Chinese fighters have the above capabilities to qualify as sixth-generation fighters.
Conclusion
It’s ironic that a lot of the concepts implemented in the design of the new stealth fighters are part of the US NGAD (New Generation Air Defense) program, which is yet to come up with a prototype. No more will the Western world be able to accuse China of copying its fighter aircraft designs.
China’s rapid advancement in military aviation technology is unquestionable. However, it’s essential to note that these are prototypes, and their final configurations, roles, and capabilities could change as they progress through the development stages.
