China’s aircraft industry celebrated Mao Zedong’s birthday in style, announcing the development of three aircraft that will form a suite of air combat systems for the 2030s and beyond. One, from Shenyang, appears to be a demonstrator of a fighter-sized aircraft with next-generation stealth capabilities, likely compatible with carrier-based aircraft. Also new is the airborne warning and control version of the Xi’an Y-20 Airlifter, the latest in our unparalleled aerial surveillance lineup.
The most spectacular debut aircraft, which took its maiden flight on Dec. 26, belonged to Chengdu Aircraft Industry Group, a stealth fighter jet identified by various anonymous commenters on the Chinese Internet as a J-36. It is the largest fighter aircraft designed and developed in China, and the second largest to fly in the past 35 years.
The J-36 (if that’s really the name) is designed to combine supersonic performance with all-round stealth. That’s also the goal of America’s Next Generation Air Superiority program, which is currently stalled by budget and policy issues. (The second article in this series will discuss the role of the J-36.)
There may be more. Anonymous Chinese Internet commenters, who have a more accurate record than others, say that the new arrivals are part of an air combat “tea set” and that we still have a “teapot”, i.e. a long-awaited He said he had not seen the H-20 stealth bomber. This will likely be an analogue of the Northrop Grumman B-21. Nevertheless, the J-36 alone is enough to intrigue observers.
That revelation followed the same pattern as the emergence of the J-20 fighter jet just 14 years earlier. Technical details have not been officially released and are unlikely to be released anytime soon, but a prototype of the design was flown during daylight hours from an airfield in a dense urban area, and the Chinese government has authorized the release of images.
This aircraft was being chased by a two-seat J-20B, giving us a good idea of its size. It is longer than the J-20 (approximately 23 meters), with an estimated total length of 19 meters and a wing area of approximately 200 square meters. (The F-22’s wing area is 78 square meters.) As commented on the World Fighter Program’s Tempest design, the large, moderately swept delta can accommodate large amounts of fuel, making it ideal for designers seeking long range. very helpful.
Tandem-wheel main landing gear units refer to large aircraft, since a single wheel, tire and brake unit is insufficient when the weight exceeds approximately 35 tons. The main weapons bay, which is approximately 7.6 meters long, and the auxiliary side bays for small arms also suggest considerable size. Takeoff weight of 55 tons is a reasonable estimate, two-thirds more than the J-20, and compared to the Northrop Grumman B-21’s estimated 82 tons.
The J-36’s floor plan clearly speaks of stealth and supersonic speed. It is an improved version of the Hopeless Diamond, the first all-stealth launch from Lockheed’s Skunk Works, so named because it was impossible to fly with 1970s technology. In 2003, another variation of this planning format was tried and flown on Northrop Grumman’s X-47A Pegasus unmanned fighter demonstrator. one time.
On the J-36, the diamond is stretched into a double delta to reduce transonic and supersonic drag. There is a kink in the leading edge, or a change in the sweep angle. Although this is not ideal from a radar cross-section standpoint, it is acceptable, as Northrop Grumman’s crank-arrow design shows. There is an unbroken edge and chine line around the aircraft, and all sensor openings are inside it (different for J-20 and other fighters). That is the basis of omnidirectional stealth.
There are no visible control surfaces other than the vertical stabilizer surfaces or trailing edges of the wings, and there are five movable panels on each side and one movable panel behind each engine. Such surfaces are called “elevons”. (There may be flight control effectors we haven’t seen yet, such as panels inset into the top surface of the wing.) The hinge line on the trailing edge surface appears to be covered by a flexible skin. Similar to the B-2 and B-21, the outer pair of surfaces were split horizontally to form a brake rudder, which was fully open in all photos of the first flight.
Erevons have provided reliable pitch and roll control since the 1950s, but eliminating the vertical stabilizer is difficult, especially on supersonic aircraft. The J-36 can rely on brake rudder when not close to the enemy. But to be stealthy in the threat zone, you need to keep them closed and use both aerodynamic and propulsion effects to keep the pointed end in front. This gives you another almost unique feature.
The J-36 has three engines, lined up at the rear of the wide central hull. Caret-shaped F-22-like intakes with swept and sloping lips under the leading edges of the wings provide power to the left and right engines, with the center engine powered by a supercar without a diverter in the upper fuselage. Air is supplied from the sonic inlet.
The three engine exhaust ports are located forward and above the trailing edge and consist of what appear to be interlocking panels. Maximizing turbofan reheat imposes horrendous thermal and acoustic loads on the trailing edge structure. (The rear groove where the Northrop YF-23’s engine exhausts did not withstand the environment as well as expected.) This is because the J-36’s engine does not have afterburning, or the afterburning used This tends to support the idea that burning is limited. For transonic acceleration.
Some commentators have suggested that the J-36 has three engines because China does not have an engine design large enough to power a twin-engine installation. This is unlikely. Even if the available engines could only provide two-thirds of the thrust needed for a production-sized twin-engine airplane, a demonstrator could be built with two-thirds the wetted area and 80 percent of linear scale; It will also be easier. Develop the final composition to make it more representative.
There needs to be a good reason to justify the added complexity. One possibility is that the two outer engines would provide enough thrust for subsonic flight while operating at full thrust and maximum efficiency, with a third engine breaking into supersonic cruise.
A variation on this theme could include a center engine optimized for supersonic flight. This provides some of the benefits of a variable cycle engine without the complexity or risk (hearing a logistics worker scream 12,000km away). A configuration that allows you to install VCE later.
One former fighter designer notes that trijet placement can be influenced by stability and control considerations, allowing for symmetrical thrust vectoring within pitch even if one engine is out of action. suggests that it is possible.
Trailing edge flaps provide thrust deflection in the pitch direction when used symmetrically and in a roll condition with the outer engine exhaust deflected asymmetrically (while still using the center engine relative to pitch). Masu. It is quite possible that fluid control (asymmetrically injecting fan stream air into the nozzles) could be used for the yaw axis.
Three 22,000 pound (10,000 kg or 100 kilonewton) thrust class engines would make the J-36 a supercruiser, an aircraft capable of flying at supersonic speeds without the use of fuel-intensive afterburning. should be enough. Its sweep angle indicates that it will do this at Mach 1.8 to Mach 2.0 (1900km/h to 2200km/h depending on altitude). The key is not to achieve sufficient static thrust, but to build an engine that can withstand the high temperatures at the compressor outlet. Chinese engine technology is moving in this direction.
Agility? High maneuverability is antithetical to the combination of supersonic cruise and range, and while the F-22 lacks the latter, it has great control power and high installed thrust (and the weight it brings) This is because it requires There are physical limitations. The J-36 trailing edge control and thrust vectoring system provides all control power for the aircraft without the aid of vertical stabilizers, canards, or pitch recovery devices such as the Sukhoi Su-57’s movable leading edge roots. There is a need. Extension.
For a discussion of the need for maneuverability in supersonic stealth aircraft equipped with heavy weapons and long-range sensors, see the classic short film Bambi Meets Godzilla.
We will learn more about the J-36, which follows the pattern of the J-20, through its pre-production and service testing phases. There are other mysteries to this design. There are obviously large electro-optical sensor windows on either side of the nose, and a dark-colored canopy that is not road legal in many US states. But one thing is clear: Those accusing Chengdu’s chief engineer Yang Wei and other Chinese designers of copycats need to stand down.
