J-8II (Jian-8 Fighter aircraft 8) / F-8
The previous models of the J-8 were handicapped in that the design of nose inlet impaired the performance of the aircraft's 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.
After the 1970s there was a noticeable change in the world fighters. Very high flying speed and flying altitude were no longer pursued but good maneuverability at low and medium altitude and improved avionics, armament and fire control system came into vogue. This was because the practice in the past ten years and many local wars had showed that most air battles between the supersonic fighters were conducted at low and medium altitude and at a speed near the sonic speed and that the dog fight in the air required the fighter to have good maneuverability, i.e. good performance in turn rate, acceleration, deceleration and rate of climb. The gun(s) and missiles mounted or carried on a fighter were of equal importance.Since the early 1980's Chinese aviation industry had closely followed the trend of world fighters, marched to a higher level and began to develop a contemporary fighter J-8 II to meet the Air Force's needs in updating and improving its combat capability.
The J-8 II was developed on the basis of J-8 aircraft but significant improvements were incorporated. The improvements were emphasized on the armament, fire control system, avionics and power plant. The intakes were moved to two sides of the fuselage, therefore the space in the nose could be saved for a big antenna of the radar. Two engines were changed to the uprated WP13As for improvement of the maneuverability at low and medium altitude. The hard points were increased for carrying several different weapons so that the J-8 II could have the all-weather interception capability as well as the ground attack capability. The J-8 II had more than 70 per cent modifications over the J-8 and one third of its total vendor-furnished-equipment were replaced.
The operational requirement of the J-8 II was approved by authorities in September 1980. The conceptual definition study was started in April 1981 and then the general configuration was determined. The development tasks were taken by the Shenyang Aircraft Design Institute and the Shenyang Aircraft Company.
The development of the J-8 II was managed with the principles of the system engineering. Under the leadership of the J-8 II chief director He Wenzhi, vice minister of the MAI, the feasibility study of the J-8 II had taken 3 factors into consideration: technology, cost and schedule. Various systems of job responsibility were established: chief designer's responsibility for design art, administration responsibility, cost contractual responsibility, and quality control responsibility. And the management was carried out in four areas: technology, cost, schedule and quality. The chief designer Gu Songfen had an important position in this system engineering management. In the area of technology there were four responsibility levels, i.e. the program chief designer, system chief designer, director designer and project designer. In this system the divisions of work and responsibility were clearly defined.
In the area of administration Tang Qiansan, general manager of the Shenyang Aircraft Company, Guan De, vice general manager and on-site chief director, and Gu Yuanjie, chief engineer, carried out their work effectively. The chief accountant used fixed-price-contract to stimulate the development of the program. Quality control was carried on throughout the development process. The designs were carefully reviewed for the second time before their drawings were released. With all these efforts, the smooth progress of the aircraft development was ensured and all the sub-systems, work items and even every work procedure in manufacturing were completed as scheduled.
The Shenyang Aircraft Design Institute began its technical and structure designs in 1982, all the drawings were released for production by May 1983. By the end of May 1984, 11,000 wind tunnel tests for 39 test items, 58 structure and system test items and 25 dynamic and static test items were completed.
The Shenyang Aircraft Company began its manufacture of production tooling and aircraft parts in 1983. It only took the company 17 months to send the prototype aircraft into the air. It was only 3 years from the beginning of the development of the WP13A engine by Guizhou Engine Design Institute, Guizhou Engine Company and Chengdu Engine Company to the delivery of the first engine for the prototype aircraft.The vendor-furnished-equipment and components for the aircraft basically satisfied the aircraft requirements.
On June 12, 1984 the graceful-looking and novelly configured J-8 II was flown for the first time by test pilot Qu Xueren.
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