On Boxing Day, Dec 26, 2024, China ‘unboxed’ two new aircraft types that shook the West’s intelligence community.
Both aircraft, presumably 6th-generation, stealth designs, feature a unique ‘tailless’ design with no vertical stabilisers for directional stability.
The bigger aircraft, tentatively known as the Chengdu J-36 is a wedged-shaped, tailless delta design that features a cockpit with a tandem seating arrangement. What makes this design interesting is that it features three engines – two located along the fuselage and under the wings, and a third, located on the ‘spine’ of the aircraft, behind the ‘bubble’ canopy.
The two ‘conventional’ intakes are fed through ‘caret-shaped’ intakes that reduces radar cross-section, and look similar to the intakes of the Lockheed Martin F-22 Raptor. The third engine is fed through a ‘NACA-styled’ inlet with a notched upper intake lip to disperse radar returns.
Comparison photos show the J-36 to be roughly the same length as the Chengdu J-20 stealth fighter – which was seen flying chase for the J-36 that day – around 70 feet in length. The two engines along the fuselage are widely spaced, suggesting that the flat underside of the aircraft could be used for an internal weapons bay. There were no hardpoints or weapons pylons on the wings, with only the six aerodynamic ‘blisters’ for the control actuators visible.
The exhausts appear to be of the ‘flat’ type instead of the conventional ‘convergent-divergent’ nozzles as in most aircraft. It is unclear if the J-36 has the ‘trough-type’ exhausts lined with tiles that are “transpiration cooled” from engine bleed air to dissipate heat and reduce its IR (infrared) signature. The exhausts do not appear to have thrust-vectoring capability.
Defence analyst Tom Cooper believes the J-36 is China’s newest strike fighter, and not a ‘pure’ fighter/fighter-interceptor, although “it has the potential (to be missionised) for that, too.”
Some observers suggested that the powerplants used in the J-36 is a combination of two ramjets, and a conventional high-bypass ratio turbofan engine. While it is possible – based on China’s advancements in hypersonic missile technology – others quickly dismissed that theory, saying the country’s engine technology had often lagged behind its capabilities in airframes, avionics, and aerostructures.
The second aircraft spotted flying over Chengdu was a smaller, tailless delta wing demonstrator with a swept wing similar to the lambda wing. Analysts believe it was likely designed by the Shenyang Aircraft Corporation, and it was seen flying alongside a J-16, a Sukhoi Su-27 clone. Both this, and the J-36 appear to have aerodynamically complex designs for a reduced radar signature.
The decision to opt for a tailless design would indicate that both types are using advanced flight control system algorithms with fly-by-wire technology to control the air vehicles. A similar system was used in the American Northrop Grumman B-2 Spirit intercontinental bomber.
The B-2 Spirit stealth bomber’s flight control system (FCS) is a complex, computer-controlled, quadruplex fly-by-wire system that helps maintain the aircraft’s stability. The Spirit is controlled in the pitch, roll, and yaw regimes through four pairs of control surfaces on the wing trailing edge. The outer elevons provide primary pitch and roll control, while the inner elevons are secondary control surfaces used at low speeds. It can be hypothesised that the J-36 and the smaller Shenyang design, use a similar principle.
The United States and Europe are only just putting their 6th-gen designs on paper – with some in the advanced mock-up stages. The UK’s Tempest is in the advanced design phase while France’s Future Combat Air System (FCAS) exists only in mock-up form. Sweden has just given the go-ahead for a 6th-gen replacement to the Saab JAS-39 Gripen.
The fact that China has rolled out two advanced 6-gen stealth designs that are already flying, is a gut-check for the West.
Main image: Chengdu J-36 (left) and the Shenyang.
