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Military


WP7B Engine Series

The Guizhou Aeroengine Design and Research Institute (GADRI) was set up at the same time as GEF. On the basis of successful work on the troubleshooting and life extension of WP7 engines, they continuously made improvements under the principle of "doing things according to one's ability, and continuously marching forward with small steps." After a few steps forward, they developed the WP7B engine series.

The WP7B was derived from the WP7A and their main difference was in the length and structure of the afterburner. Because of the cracks on the first stage turbine blades, high rejected rate of castings and the higher wall temperature of the afterburner which " burned" the rear fuselage, the engine could not be certified and released for operation. GEF under took 24 improvements in structure, manufacturing processes, material and accessories. In order to solve the first stage hollow turbine blade problem, director Wang Xinming went to the workshop to organize tackling the key problems. Shi Changxu, deputy director of SMRI of the CAS gave his direction on the spot. After hard work, the strength of blades and an acceptable rate of casting were increased. To solve the problems of the afterburner, engineer Jiang Zhizhong designed a three sectioned heat shield, which reduced the wall temperature by 100 C , and the problem of burning the rear fuselage was solved. In the meantime, the Guizhou " Hongshan" Bearing Factory, Chongqing "Yiping" Chemistry Factory, Guizhou Aero-Rubber Factory, BAMI, etc. successfully developed high temperature aero-bearings, and high temperature synthesized oil and fluoride rubber sealing rings and the problems were solved one by one. By the end of 1978, the WP7B engine smoothly passed the State type certification test, with an increase of 6.1% in wet thrust compared with the original WP7 engines.

According to the requirements of the Air Force and the export market, the factory made further modifications to extend the operation life, with particular emphasis on the combustion liners. They modified the structure of the body and cover, increased the ability to sustain the ingested exhaust gas, modified the flange design to solve crack problems, and changed the three-sectioned air film cooling to five-sectioned, thus doubling the operation life. With other improvements, they extended the engine life from 100 hours to 200 hours and designated the engine the WP7B.

The factory then changed the seperate gasoline starter into the kerosene starter which took the fuel directly from the main pump. This change reduced the weight, improved the air starting both in time and in reliability and made field maintenance easy. This modification succeeded in 1981. In 1982, it was put into series production and exported. It gained much praise from the end-users, and was named the WP7B(M batch) engine.

At the same time, another design modification was carried out to reduce the engine weight by 17 kg, which satisfied the requirement of the export version (J-7M aircraft) to add drop tanks. It was released for series production at the end of 1982 and was named as the WP7B(BM batch) engine.




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Page last modified: 11-07-2011 02:48:17 ZULU