The CJ-6 is an all-original Chinese design that is commonly mistaken for a Yak 18A. Its predecessor, the Nanchang CJ-5, was a licence-built version of the Yak-18. However, advancements in pilot training brought a need for a new aircraft with improved performance and a tricycle landing gear. When the Soviet Union developed the Yak-18A, PLAAF engineers decided that its performance and design would not suit China's needs. During late 1957 Aeronautical Engineers Cheng Bushi and Lin Jiahua began work in Shenyang on a trainer design that addressed the shortcomings of the Yak-18A. The design they delivered featured an aluminum semi-monocoque fuselage, flush-riveted throughout, and introduced a modified Clark airfoil wing design with pronounced dihedral in the outer sections. The dihedral and an angular vertical tail distinguish it externally from the otherwise rather similar Yak-18A. Wind tunnel testing validated the design, and in May 1958 the program was transferred to the Nanchang Aircraft Manufacturing factory where Chief Engineer Gao Zhenning initiated production of the CJ-6. The first flight of the CJ-6 was completed on August 27, 1958 by Lu Maofan and He Yinxi. Power for the prototype was provided by a Czech-built horizontally-opposed piston engine, but flight testing revealed the need for more power, so a locally manufactured version of the Soviet AI-14P 260 hp radial, the Housai HS-6, was substituted along with a matching propeller, and with that change the CJ-6 was approved for mass production. In 1965 the HS-6 engine was upgraded to 285 hp and redesignated the HS-6A, and the aircraft equipped with the new power plant were designated the CJ-6A. A total production run estimated at more than 3,000 aircraft supplied CJ-6 aircraft for PLAAF training, as well as for export (as the PT-6) to countries including Albania, Bangladesh, Cambodia, North Korea, Tanzania, and Sri Lanka. Specfications below are for the improved and more powerful CJ-6A variant.