J-8 (Jian-8 Fighter aircraft 8) / F-8
The J-8 was the first PLAAF aircraft of domestic design, with design work beginning in 1964. The overall configuration is a rather straightforward enlargement of the MiG-21/J-7 layout to accomodate two engines. Although it resembled Mikoyan's experimental Ye-152A, contrary to some early reports, it was not based on that aircraft. Production began in December 1979, with about 100-150 units of the first configuration entering service. Design work on the improved J-8-2 began in 1980, with production beginning in the late 1980. As with the cancelled "Super 7" upgrade to the single-engine J-7, the J-8-2 completely reworks the front end of the aircraft, adding a much larger radar and ventral air inlets, along with various other less pronounced improvements. The best that can be said of the J-8 is that once upgraded it will be no more than an advanced obsolete aircraft, comparable in configuration and aerodynamic performance to the Su-15 FLAGON.
Developed by Design Institute 601 and the Shenyang Aircraft Factory, the J-8’s design of focused around five aspects: high altitude, high speed, extended range, high climb rate, and enhanced fire power. Overall, the J-8 was superior to the J-7. The J-8 could reach Mach 2.2, had a maximum ceiling of 20,000 m, a range of 2,000 km, and could climb at 200 m / s. The J-8 was armed with two cannons and two air-to-air missiles, accompanied with a more powerful radar with increased search distance. The J-8 characteristically has a nose inlet, a highly sweptback, low aspect ratio delta wings, low tail planes, and two ventral fins.
As for the powerplant of the J-8, two proposals were made. The first proposal suggested the use of a newly designed afterburning, turbofan engine. This suggestion was risky as the engine would have to be developed alongside the aircraft and could potentially be unsuccessful. The second proposal involved using improved versions of the WP7A engines. The WP7A’s performance was lower than the former, but it had already been proven before to be a proven and reliable engine. As a result, the WP7A engines were selected instead.
The J-8’s research and design peaked in the summer of 1965. The design of the aircraft was completed in 1967. In the research, the Chinese made gains in the design of aircraft flying at high mach speed, mostly in regards to the directional stability of the aircraft. J-7’s were utilized for the supersonic research, in which the data from the research served as a foundation for further J-8 development.
The improvement of the engines was previously hampered by a problem with the hollow blades of the engine. Additionally, the blades could not withstand the high temperatures needed for the turbo inlets to operate at. As a solution, newly developed superalloy, air-cooled hollow blades were utilized in the aircraft, allowing the turbo inlet temperature to be raised substantially.
The trial production of the J-8 began coincided with Great Cultural Revolution. Production of the J-8 was hampered, as factory workers were prevented from working due to the violence in 1967. Production continued at a slow pace, and few test aircraft were built. As a result, certification of the J-8 lagged as testing took 10 years, beginning in 1969. The lag was also due to the fact that much of the new technology developed for the J-8 was unproven, there was an insufficient number of test aircraft, and the team responsible for the development of the aircraft lacked experienced personnel.
The testing of the J-8 was not without obstacles. Such problems included the vibration created when the aircraft flew at transonic and supersonic speeds, which was corrected by modifying the aft fuselage’s geometry. Another problem involved the overheating of the aft fuselage at supersonic speeds, which was solved by improving the cooling valves. The test flights of the J-8 also had issues of in-flight shut down, which was remedied with the addition of a throttle retainer block and an angle of attack compensation device. The J-8 was finally certified in March 1980.
Variants
The J-8I
The initial J-8 model was limited in that it could not operate at night and in did not have all weather capabilities. Development for a second, all-weather version of the J-8 (designated as the J-8I) began in 1976. For improvements, 11 additional avionics upgrades were added, one of which was an all‑weather radar. The J-8I also features a newly designed canopy, seat, oxygen system, and integrated instruments. In regards to armaments, the J-8I was given a new cannon and had the capability to carry up to 4 air-to-air missiles and 4 rocket pods.
Design for the J-8I was completed by in early 1978, thus allowing the Shenyang Aircraft Factory to commence trial production. In May of 1980, the first production aircraft was rolled out, however it unfortunately was destroyed in a fire caused by the aircraft’s faulty hydraulic pump. The unproven hydraulic system was replaced with a new pump designed by Institute 601 improved the design in accordance with the lessons learned and replaced the hydraulic pump with a different type pump. In April 1981, a new J-8I was produced. Testing finally resumed, which took an additional 3 years to produce.
An important feature of the J-8 was the addition of a fire control system, which was a paired with a Type 204 monopulse radar developed by both the Ministry of Aviation Industry and the Ministry of Electronics Industry. The Type SM-8 aeronautical optical gunsight was the first Chinese system that utilized a rate gyroscope, which resulted in higher performance and firing accuracy. The J-8I paired with the system was tested in 1982.
The J-8II
The previous models of the J-8 were handicapped in that the design of nose inlet impaired the performance of the aircrafts airborne fire control radar. In 1979, the Chinese made a proposal to redesign it so that the inlet of the engine was in located in the sides of the fore fuselage. The re-designed aircraft became a new variant of the J-8 in 1980, designated the J8-II. Institute 601 and the Shenyang Aircraft Company once again were placed in charge of the development of the new J-8II.
The design principles of the J-8II stressed that not only is the aircraft capable of high speed and high service ceilings, but also that the aircraft be maneuverable at both transonic speeds and in medium-low altitudes. It was also guided by the idea that a fighter should be able to perform beyond visual range capabilities with the assistance of improved avionics, armaments, and fire control systems.
The J-8II was refitted with two WP13AII engines for increased performance. Additionally, a new radar for the fire control system was added in order to increase the operational range of the J-8II, as well as an interception fire control system. As for armaments, radar guided medium range missiles and air-to-ground rockets became new weapon options. Lastly, an autopilot system was also added, thus giving the J-8II all-weather interception and ground attack abilities.
The moving of the inlets to the sides of the fore fuselage from the nose of the aircraft was a sharp departure from the usual design of Chinese fighters, in which the nose had always had the air intake. Because of this, Institute 601 conducted a large number of tests to ensure the function of the design.
As for the performance of the aircraft, the J-8II’s intake efficiency was the same as the J-8 at high speeds and 6% higher at lower speeds. The intake efficiency maintained the level of the J‑8 at high speed and was 6% higher at low speed. A electrically controlled differential horizontal tailplane also contributed to the enhanced performance of the J-8II. As a result, the J-8II was 45% more efficient in roll control compared to the J-8 in sub-sonic speeds.
Guizhou Engine Design Institute and the Guizhou Engine Company were responsible for the development of the WP13AII engine. Compared to the previous engine, a high temperature turbine was put in place, which increased the turbine’s entrance temperature. As a result, the thrust of the engine was improved.
The design plans for the J-8II were released to the Shenyang Aircraft Company in April 1983, which commenced trial production. In March 1984, the first J-8II was produced and was successfully flown in June 1984 and certified in October 1988 after completing its test flights.
During the 1990s two trainer programs were initiated in China -- the J-8 intermediate trainer and the JJ-7A advanced trainer. The J-8 program was hampered by US government's refusal to sell more TFE-731-2A turbofans, but problem was later solved by using indigenous (WS-11) or Ukrainian (AI-25TL) engines and J-8 finally entered series production.
The J-8 and J-8II aircraft are trouble-prone aircraft with a poor weapon suite and an inefficient engine. At best, the J-8-II can be compared with an early model (1960s) US F-4 Phantom. In fact, after twenty-six years the J-8-II is still in the development stage, has resulted in only about 100 fighters deployed, and meets none of the requirements of the PLAN.
The Jian-8IIM upgrader, co-developed by China and Russia, is the result of a thorough modernization of the F-8M fighter ("M" standing for export-only weaponry in China's weapon designation system) and has actually become a new-generation fighter plane. The first flight of this version was conducted on 31 March 1996. It features upgraded electronics systems, the lack of which has disadvantaged China's fighter planes for a long time.
The twin-engine Jian-8IIM is claimed to be better equipped to survive damage than single-engine F-16A/C and Mirage 2000 series. The high-altitude high-speed performance of the Jian-8IIM is superior to the F-16A/C, F-18, and Mirage 2000; and its radar and electronic equipment are better than those of the F-16A and are similar to those of F-16C, F-18,and Mirage 2000-5. By using the new, powerful WP-13B engines, the Jian-8IIM fighter boasts greatly improved low-altitude maneuverability, which is slightly better than that of the F-18 and Mirage 2000-5, but still inferior to that of the F-16. The Jian-8IIM fighter will probably be equipped with Russia's or China's helmet sight and advanced PL-9 and P-73 missiles, with which it will outperform the F-16C in close-range air combat. Phazotron, a Russian firm, has signed contracts with China to provide 150-200 improved Zhuk radars mainly in support of China's new F-8II fighter, but also to equip the new Chengdu J-10 fighter. These radars have six times the data and signal processing power of the basic variant and greater detection range than the current 80KM. They can track while scanning on 24 targets, display up to 8 of them, and simultaneously provide fire-control solutions for 2-4 of them.
The Jian-8IIM does not use large amounts of expensive composite material and titanium alloy, and it is not equipped with complicated maneuverable flaps, as found on the F-7MG and F-16. Consequently, although their combat capabilities are similar, the Jian-8IIM is much cheaper than the F-16C. Though mature and reliable, the Jian-8IIM is rather cumbersome. With a fuel load exceeding that of the F-16, its operating range is shorter than that of the latter. However, if specified by a customer, the Jian-8IIM could incorporate composite material, titanium alloy, and maneuverable flaps to further enhance its maneuverability and expand its external storage capacity and radius of action.
