China quietly took an enormous step in military manufacturing last year when it introduced a turbofan (jet) engine designed and built in China. Only four other nations design and build their own jet engines (US, UK, France, Russia). For nearly three decades, China has been building foreign engine designs under license. Several other nations do this, but designing your own requires a considerable scientific and industrial investment. The new Kunlun engine is built to replace the Russian engines in the Su-27s and Su-30s that China is buying from Russia. China currently pays about three million dollars each for the Russian AL-31 engines. But the Kunlun is expected to cost less than $800,000 to build. There is some suspicion that the Chinese simply reverse engineered the Russian design, but the Russians will have to get their hands on a Kunlun engine to determine this, and the Chinese are not allowing that close an inspection just yet.