JJ-7 Advanced Trainer
Since the beginning of 1980s the J-6s in the military services have been gradually replaced by J-7s and J-8s. The supersonic aerodynamic layouts of these two generations, J-7 and J-8, are significantly different from their predecessors. The JJ-5s and JJ-6s were no longer considered to be the most suitable trainers to train pilots for J-7s and J-8s because the conversion period was too long and even unsafe. Therefore, the MAI made a decision to develop a new trainer — JJ-7.
Various versions of the J-7 and the export of the J-7 to foreign customers prompted the Chinese military to develop a trainer version of the J-7. As a result, the Guizhou Aircraft Design Institute and the Guizhou Aircraft Company jointly began developing the trainer version of the J-7, which was designated as the JJ-7. Based on the J-7II, the JJ-7 is a supersonic fighter‑trainer and primarily used for the training programs of the J-7 and J-7 II, and the J-7M.
Improvements and additions of JJ-7 consist of an aft cockpit, a new forward view periscope, twin ventral fins, fuel tanks inside the top fuselage, modified intake, improvements in the ejection escape system, air conditioning, a new fuel system, red cockpit lighting, an interphone system, and a failure simulation system. The conceptual design was started in 1979, and was completed in 1983. Trial production also began that same year. Static testing of airframe carried out and finished in May 1985. Fight testing began in 1985 in Guizhou. In the first flight tests, the JJ-7’s cockpit was too high due to problems in the air conditioning system. This problem, however, was eventually solved.
The design of JJ-7 was derived from J-7II by the Guizhou Aircraft Design Institute and the Guizhou Aircraft Company. Its conceptual definition study began in 1979 and the main operational requirement was issued in 1981. All the design drawings were completed by the I design institute in 1983 and the factory started the prototype production immediately after the release of drawings. The full size static test was completed on June 12, 1985. On July 5 test pilot Yan Xiufu flew, the domestic JJ-7 for its first time over the Guizhou plateau and landed safely after all flight test subjects had been completed.
The JJ-7 differed from the J-7 II by addition of an aft cockpit, relocating the pitot tube t the upper right of the nose, ensuring the ejection escape safety of two pilots in emergency with sequenced ejection system, additions of a "failure simulation system" and an interphone an adoption of red cockpit lighting. Approximate 40 per cent of the drawings were changed.
JJ-7 could not only perform all the day time training, subjects of the J-7 in fair or adverse weather but also the most training subjects of the J-8. In addition it also had certain air combat and ground attack capabilities.
In order to enhance the leadership to the design and the prototype production, the MAI set up a Chief Designer System and an On—site Directing Office of the JJ-7 and appointed Yu Xiuming chief designer and Tang Wenbing chief director. The administrative system cooperated closely with the Chief Designer System to take charge of the necessary vendor— furnished—equipment and accessories, coordination, quality and schedule based on the development plan, and ensured the smooth development. The staff and workers overcame many difficulties caused by insufficient infrastructure, know—how and budget, worked meticulously in their designing, testing and manufacturing and tackled many key technical problems.
It was very hot when the ejection test of an escape system was carrying on in Henan province in the middle of June, 1984. But all the people of the test team from the Guizhou Aircraft Company, the Guizhou Aircraft Design Institute and the Hubei Escape System Research Institute worked in open air, completed the seat ejection tests at high, medium and low speeds and obtained satisfactory test results. It was bitterly cold when the Guizhou Aircraft Company was carrying on a dorsal fuel tank pressurization test. The test site was also in open air. During the test the empty fuel tank had to be placed in the water at the depth of 1.3 m and then pressurized and carefully checked. The test had to be repeated a number of times. In order to find every minor leakage Wang Jianchang, a tester and a Party member, stayed in the cold water for dozens of minutes to perform detailed checks in every test. It was so cold that his lips turned purple. When his leader bought him some liquor and ask him to drink to warm his body, he answered: "I don't drink liquor and I don't feel cold either. Doing test is my job and my duty too." It was because the hard work of these heroic and moving unknown heroes like Wang Jianchang that the triumphant birth of the JJ-7 in Guizhou plateau was seen.
In February 1988, the design of the JJ-7 was certified. The JJ-7 gave the Chinese a Mach 2 trainer and was made available for export.
During the 1990s two trainer programs were initiated in China -- the J-8 intermediate trainer and the JJ-7A advanced trainer (Jianjiji Jiaolianji = JJ = Fighter Trainer).