The former is a newly developed large thrust engine scheme, and the latter is a modified trial-production scheme using mature engines. Under the auspices of Tang, president of the Aviation Research Institute, the meeting decided to adopt the scheme of two engines. This correct choice is safe and reliable, and has a certain technical foundation, which is the prerequisite for the successful development of the J-8 aircraft. 1May, 965 17, Chief of General Staff Luo Ruiqing approved the tactical and technical indicators and development tasks of the new fighter. This plane was named J-8.
Its main development work is undertaken by Shenyang Aircraft Design Institute and Shenyang Aircraft Factory. National leaders are very concerned about the development of the J-8 aircraft. 1August, 965 14, Vice Premier He Long instructed: "The J8 should be produced as soon as possible" when listening to the report on the development of the J8 in Shenyang. On August 18, in a letter to Deputy Chief of Staff Zhang Aiping, Marshal Nie Rongzhen expounded several problems that must be considered in the design of the new aircraft, which played an important guiding role in the development of the J-8 aircraft.
The development scheme of the J-8 aircraft highlights the performance of high altitude, high speed, extended range, improved climb rate and enhanced firepower.
Aiming at the shortcomings of the J-7 aircraft, the air-to-air missile was improved item by item, and all performance indexes were improved: the maximum speed was 2860 km/h; The maximum ceiling exceeds 20,000 meters; The maximum climb rate is 200 meters per second; Basic range 1500 km, maximum range 2000km；; The air combat time at an altitude of10.9 million meters is stipulated; Install improved design guns and air-to-air missiles; Install a radar with a long search range. This J -8 aircraft adopts the aerodynamic layout form of nose intake, large sweep angle, small aspect ratio, thin delta wing, flat tail and double ventral fins. Two turbojet 7A engines are selected, and the thrust-to-weight ratio of the aircraft is 0.89, which is superior to that of the J-7 aircraft.
1September, 1965, the design of the J-8 aircraft was in full swing. After the chief designer Huang died in a plane crash abroad in May this year, the technical work of the new machine development was led by Ye and organized by the chief designer's office headed by Wang Nanshou. In the same year1February, the wooden prototype of the J-8 aircraft passed the examination. 1March, 1966, designers went to the factory to carry out on-site design with workers and technicians. At the end of 1966, a complete set of aircraft drawings was issued, and at the beginning of 1967, the corresponding production documents were issued, and the factory immediately began trial production.
During the development of airborne radar, designers have broken through many technical keys. In terms of aircraft aerodynamic layout, the biggest problem in designing supersonic fighters in the world at that time was to ensure the directional stability of the aircraft at Mach number. Gu Songfen, deputy chief designer, presided over the design research, and Ge Wenyong, an excellent pilot sent by the Air Force, cooperated to measure the directional stability and flying quality of the J-7 aircraft at Mach number, which provided reference and basis for the design of the J-8 aircraft. Technicians from 60/KLOC-0 Institute, Shen Fei Factory and Aerodynamics Research and Test Department, together with Beihang University and Professor Xu, have done a lot of wind tunnel tests and research and analysis, and finally determined the design scheme of the vertical tail and ventral fin of the J-8 aircraft, ensuring good directional stability at Mach number.
Wing flutter of supersonic aircraft is the most dangerous aeroelastic phenomenon, and it is also an important factor restricting the maximum speed of aircraft. Guan De presided over the aeroelastic design of the J-8 aircraft, established a set of unsteady aerodynamic and flutter calculation programs, and made a large number of wind tunnel tests, ground vibration tests and real aircraft flight tests, and comprehensively determined the flutter characteristics of the aircraft. After adopting the above scheme, it not only ensures the aircraft to achieve the predetermined performance, but also minimizes the structural weight, thus improving the thrust-to-weight ratio of the aircraft. In addition, presiding over aircraft strength calculation and aircraft structure design has also achieved good results.
In the improved design of turbojet 13A2 engine, the technical breakthrough of hollow blades has been achieved. In order to increase the thrust of the engine, the temperature in front of the turbine must be increased by about 100 degrees Celsius, and the turbine blades can't bear such a high temperature. 1964, Ke Rong, deputy director of 62 1 research institute and casting expert, proposed to adopt hollow air-cooled blades. At that time, this technology had just developed abroad and was in a highly confidential state. Ke Rong cooperated with Shenyang Metal Research Institute, 606 research institutes and Shenyang Engine Factory to tackle key problems. Under the auspices of Shi Changxu, Shenyang Metal Research Institute organized technical research to overcome the technical difficulties of blade casting.
The first is the core choice. Small holes with different thicknesses should be evenly discharged on the blade with a length close to 100 mm, and the smallest aperture is only 0.8 mm After research and experiments by scientific and technical personnel, a usable mold was finally made, and technical problems such as coring and ultrasonic wall thickness measurement were solved one after another. 1966, the first cast porous air-cooled nickel-based superalloy blade in China was developed, which was completely successful after being installed on an engine, thus narrowing the gap between China and the United States in this respect and becoming the second country in the world to adopt cast hollow blades on aero-engines.
The ammunition supply and discharge system of the J-8 aircraft gun is a design difficulty. It must ensure that the cannon can be fired continuously in the air. Previously, experts in the former Soviet Union thought that the design of this system was their patent and kept it secret. This time, designers and workers did experiments together, modified an air gun that can simulate shooting and fired 10 thousand fake bombs. Finally, the law was found and the design was successful.
China J-8 fighter Shenyang Aircraft Factory started the trial-production preparation of J-8 aircraft in the second half of 1965. Under the leadership of Gao Fangqi, the first deputy director and chief engineer, Luo Shida, the deputy chief craftsman, presided over the formulation of the 歼 8 process plan. This master plan was formulated on the basis of integrating the advanced experience of the former Soviet Union and Britain. This scheme adopts a new process matching method, that is, based on the mold line of gelatin plate, using optical instruments, fixture assembly machine and marking drill floor. Coordination method of combining local gauge setting with local mold and tire. Later practice shows that the whole machine has more than 1 1400 parts. 1, more than 200 standard parts, from more than 1, 000 assemblies to the front and rear fuselage, fuselage wings, and then to the installation of engines and fuel tanks on aircraft, are basically successful. The new method also greatly reduces the process equipment and speeds up the trial production progress of the J-8 aircraft.
1967, under the impact of the "January Storm" and the "Cultural Revolution", the production order of the factory was seriously damaged, and the production on the production line almost stopped. The vast number of scientific and technological personnel and workers even risked their lives to go to work. Even in July and August, when the fighting was the fiercest, the development of J-8 didn't stop. 1July, 968, the first batch of two 歼 8 aircraft completed the final assembly.
Turbojet 7A Engine1On July 5th, 969, the J-8 aircraft made its first test flight. At 9: 30 in the morning, Cao Lihuai, commander-in-chief of the test flight site and deputy commander of the Air Force, ordered the release. Pilot Yin Yuhuan flew the J-8 plane over the airport twice and landed safely. At this time, people standing at the airport gave a warm cheer. Hail the success of the first flight of China's first self-designed high-altitude high-speed fighter. From the conceptual demonstration to the first flight, the J-8 aircraft experienced four years and ten months, including general layout, technical design, wooden prototype evaluation, drawing distribution, new machine manufacturing and testing.