J-20 fighter might need Russian engines

As China reaches an agreement with Russia to buy Su-35 fighters, the domestic J-20 fighter program might have developed problems that China cannot solve on its own anytime soon. Prompted by the well publicized Su-35 deal, photos of the second J-20 prototype undergoing flight tests became easily available on Chinese websites recently, likely to assure the public that the J-20 program is proceeding well. This aircraft made its first flight last May. The first prototype made its maiden flight in January 2011, grabbing much international attention.

It made more than 60 additional flights that year. A third J-20 prototype is believed to exist, but only for ground and lab tests.

The recent J-20 photos featured white circles on the fuselage of No. 2002. These are thought to be markings for optical measurements of the airplane from the ground or from another aircraft, as is routine in new combat aircraft development. Some unofficial Chinese commentators concluded that J-20 weapons systems tests had begun, marking an important milestone.

In contrast to the optimism based on a few photos, however, the fact that China has yet to succeed in developing a powerful engine for the J-20–the much-expected WS15–tells a different story. Of the two J-20 prototypes that have been made known to the public, one is powered by the Russian-made AL31FN and the other by the domestically builtWS10G. The Chinese version of the Su-27SK, the J-11, is powered by the WS10A. Many observers believe that a strong incentive for China to buy the Su-35 is the airplane’s 117S engine, an AL31 derivative.

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