Stealth of Chinese 5th generation fighters
By now aviation Chinese industry has developed two fighters of the latest 5th generation. One of them, Chengdu J-20, is already being mass-produced and serves in the PLA Air Force, and the second, Shenyang J-31, is still being tested. When creating these machines, all current trends and ideas were taken into account. In particular, both aircraft are made inconspicuous, for which the entire range of current stealth technologies is used.
two planes
The development of the future J-20, according to various sources, began back in the nineties. By the end of the 2011s, the CAIG / CAC corporation built and brought the first prototype aircraft to preliminary tests. In early 2017, he made his first flight. Testing and fine-tuning took almost six years, and only in 150 the aircraft entered service. As part of mass production, at least XNUMX new fighters have been built to date.
CAIG / CAC continues to develop the project. So, in October 2021, a newly built two-seat version of the aircraft, known as the J-20C, was spotted at one of the airfields. Apparently, this project is still in its early stages and far from the series.
The J-31 project from SAC Corporation, also known as the FC-31, was also created in the 2012s. The first flight of such a machine took place in October 31. According to known data, flight and other tests are still ongoing. At least four prototypes were built for their implementation. When all current activities will be completed, and the finished J-XNUMX will be put into service, is unknown.
In October last year, tests of the deck version of the J-31 began. This aircraft is generally similar to the base model, but has several characteristic elements. It can be assumed that the development of this machine will take several years, and it will go into service with the PLA Navy at the same time as one of the future aircraft carriers.
The projects of the J-20 and J-31 aircraft at one time became a reason for pride. With their help, China was able to enter a narrow circle of countries capable of developing and building the latest generation of fighters. In addition, two projects confirmed the competence of the Chinese aircraft industry in various areas, including the so-called. stealth technologies.
stealth glider
As you know, the visibility of an aircraft in flight is achieved in several ways, and the main ones are related to the design of the airframe. The appearance of the J-20 and J-31 shows that stealth was taken into account in their design. At the same time, the resulting aircraft have both recognizable features and their own characteristics.
The J-20 fighter was built according to the "duck" scheme, which is not typical for modern stealth aircraft. However, the presence of the front tail, it seems, did not prevent the reduction of radar visibility. To ensure such characteristics, the fuselage and engine nacelles have characteristic rounded edges, and flat surfaces are inclined. The sweep angles of the planes, the collapse of the keels and even the characteristic beveled air intake also work for stealth.
J-31 is built according to the normal scheme and outwardly resembles foreign developments. In this case, straight and rounded edges, flat surfaces, etc. are again used. It is curious that such an exterior became a reason for accusations. The Chinese industry was suspected of using - or even stealing - foreign developments.
According to known data, both airframes are built from metal and composite parts. The use of radar-absorbing coatings and panels has been mentioned, but the details of such technologies are not known. It is also unknown how the two designs differ in terms of materials. Available photographs of unpainted aircraft allow only preliminary conclusions.
Both Chinese fighters have internal cargo bays that hide the payload from exposure. The J-20 used a combination of a large compartment along the axis and two side compartments containing limited size missiles. The compartment/bay configuration on the J-31 is unknown. Probably, the smaller aircraft has only one "bomb bay". In order to correctly reflect radio signals, the ends of the compartment doors have a beveled or serrated shape. The landing gear doors and various technological hatches are decorated in the same way.
From certain angles, the aircraft unmasks the cockpit. Probably, this issue is resolved with the help of a metallized lantern of optimal shape. Such a product should reflect the probing signal and not allow it to penetrate inside and be reflected from complex internal surfaces.
Visibility of engines
Certain risks of unmasking are associated with the propulsion system of the aircraft. Thus, a turbojet engine produces a powerful hot jet, visible to infrared surveillance systems. In addition, the traditional round nozzle can reflect the radio signal back to the locator. In Chinese projects, both of these problems are likely to be solved.
Early J-20s used a pair of WS-10C engines with a stock round pilot nozzle. In 2014-15 an aircraft with an updated engine was tested, which received a flat nozzle with jagged flaps. In the future, such an engine went into series and was installed on new-build fighters. Apparently, the new nozzle did not worsen the technical and flight characteristics of the aircraft, but reduced its visibility in all spectra. Unfortunately, the exact changes in these parameters remain unknown.
The J-31 project has not yet received such a development. All known prototypes are equipped with round nozzle engines. Accordingly, visibility from rear corners may be above the desired limit for both radar and optical aids.
Radio silence mode
During a covert flight, a stealth aircraft should not manifest itself by any kind of radiation, which imposes special requirements on the complex of radio-electronic equipment. A fighter cannot get by with only an airborne radar and needs other means.
According to known data, the main means of detecting and controlling fire on the J-20 is radar with AFAR. If it is impossible to use it, the aircraft must search for targets using an optical-location station located under the forward fuselage. It is also known about the presence of several optical devices that give a circular view. Probably, the J-20 can receive target designation from AWACS aircraft or ground control posts - this also contributes to covert work.
The avionics of the J-31 fighter was built in a similar way. He can search for targets himself using radar or "distributed" OLS. Combat work on external target designation should also be provided.
In the medium or long term, the PLA Air Force may receive multi-purpose UAVs of the "faithful wingman" type. They will work alongside the 5th generation fighters and carry out their orders. Accordingly, manned aircraft will be able to remain at a safe distance from the enemy and more fully use the stealth potential. At the same time, a corresponding improvement in avionics is required - in the current configuration or with further upgrades.
Technologies and their implementation
As reported, in two projects of 5th generation fighters, the Chinese industry used all its latest developments in various fields. Taking into account the requirements for a new generation of aviation technology, much attention was paid to the issues of visibility reduction. So far, the success of such measures can only be assessed empirically. exact data on the characteristics, in Chinese or foreign sources, is not yet available.
In the Chinese projects J-20 and J-31, all the basic principles of a comprehensive reduction in visibility in flight and in solving a combat mission are implemented. This shows that the Chinese aviation industry has a wide range of necessary technologies that now allow it to build full-fledged stealth aircraft. To develop and build a new generation of fighters, China had to create and master the production of modern alloys and composites, new engines, various aircraft equipment and weapons. It was also required to create their own scientific base in the field of stealth technologies.
At the same time, the considered fighters still retain some shortcomings. First of all, there are problems in the line of engines with low infrared and radar visibility. So far, only one of the aircraft has received a new power plant, while the prospects for the second in this context are unknown.
In general, the J-20 and J-31 projects showed the level of Chinese aircraft manufacturing and the range of advanced technologies available, at least at the time of their appearance. At the same time, stealth technologies naturally attract the most attention, since they are reflected in the appearance and other features of the fighters - and they are quite easy to evaluate. It is quite possible that in the future, China will show new stealth aircraft, and they will again demonstrate what ideas and technologies the industry has been able to master over the past time.
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