Improvements made to the basic trainer used by the Voyenno-Vozdushnyye Sily (VVS - the Russian Air Force), the Yakovlev UT-2M, in 1943 led to the first flight of the prototype Yak-18 two years later. Entering production in 1947, it was a low-wing tail-dragger monoplane of all-metal construction covered with a mixture of metal and fabric. The tandem cockpit configuration of the UT-2M was retained but instead of being open, it was covered with a perspex canopy (a blessing for flying in a Russian winter) and a 145 hp Shvetsov M-11FR radial engine provided power, albeit a modest amount. 1955 saw the Yak-18 back on the drawing board as modifications were made to the design so it could be used as a basic trainer for future Mig pilots. Unfortunately, the extra weight incurred in lengthening the fuselage, fitting partially-retractable tricycle landing gear and making alterations to the wing meant that when the M-11FR powered prototype flew, it was severely underpowered. The fitting of a 260 hp Ivchenko AI-14R soon overcame this problem and the aircraft entered production as the Yak-18A, serving for many years as the primary trainer for the VVS in Russia as well as in many other Eastern bloc countries.
Production under licence of the Yak-18 also took place in China at the Nanchang Aircraft Manufacturing Company from 1954. Given the name Chuji Jiaolianji-5 (Basic Training Aircraft 5), or CJ-5 as it was more commonly known, it entered service with the People's Liberation Army Air Force as an ab-initio trainer. With the introduction of jet aircraft into the PLAAF, the underpowered M-11FR engine left a lot to be desired in the way of power (or lack thereof to be more precise) meaning that, like the Yak-18 in Russia, the CJ-5 was unsatisfactory for training jet pilots. Consequently, the Chinese decided that instead of just simply building copies of the Yak-18A, which they were not entirely satisfied with anyway, they would design a trainer to meet their needs. A young engineer named Bushi Cheng was assigned the project and in 1957 he, and another engineer called Lin Jiahua, began design work on the new trainer at the Shenyang Aircraft Corporation.
Cheng had already designed a jet powered trainer (the JJ-1) for the PLAAF that had never gone into production; however, he felt that it would form a good basis for a piston engine aircraft. Resurrecting the plans of the JJ-1, Cheng and Jiahua combined them with the improvements required in the Yak-18 and designed, then built a mock-up of the new aircraft. Following wind tunnel tests and fine tuning of the design, the project was transferred to Nanchang in May 1958. That company's chief engineer, Gao Zhenning, wasted no time getting construction of a prototype underway and 21 days later it was completed. The aircraft was a low-wing monoplane of all-metal, semi-monocoque construction with an aluminium alloy structure as opposed to the steel tube used in the Yak-18. In keeping with its intended use as a military trainer, the aircraft was fully aerobatic, being stressed to +6.5 and -3 G. Instead of the hydraulic systems found on most aircraft, it featured a pneumatic system for the operation of the flaps, retractable tricycle landing gear, wheel brakes and engine starting. A separate blow down air system was also installed to lower the landing gear in the event of an emergency. Tandem seating for a student and instructor in an enclosed cockpit was provided. Both the front and rear positions were equipped with a full and identical set of controls and, apart from starting the engine, the aircraft could be flown from the rear seat (normally the instructors position) as easily as from the front. Much of the cockpit instrumentation and layout was from the Yak-18; the reasons behind this were twofold. Firstly, aircraft instrument production was in its early stages in China and there was an ample supply of Yak parts available and secondly, most of the pilots transitioning to the new trainer would be coming from the CJ-5, which was essentially a Yak-18.
On August 27, 1958, pilots Lu Maofan and He Yinxi made the first test flight in the new trainer; however, its performance fell short of the PLAAF requirements. It was felt that the problem may have been in the choice of the M-11FR engine instead of a Czech built, horizontally-opposed engine originally planned. A change of engine was sought and when this didn't cure the performance woes, the prototype was sent back to be redesigned. Just over two years later on October 15, 1961, the remodelled prototype made its first flight and this time it was successful. After gaining official approval, production of the aircraft commenced in early 1962 as the Nanchang CJ-6. A change of engine from the 260 hp Zhuzhou Huosai HS-6 (a Chinese version of the Ivchenko AI-14R) to the 285 hp HS-6A in 1965 led to the CJ-6 becoming the CJ-6A. Between 1964 and 1966 small numbers of an armed version, the CJ-6B, powered by a 300 hp HS-6D engine were also built and used for border patrol.
In response to a need for a multi-purpose forestry and agricultural aircraft, the CJ-6 underwent another transformation in 1985 and became the Haiyan (Petrel). Conversion work began in April 1985 with an upgraded 345 hp HS-6A engine and new propeller being fitted to the slightly modified airframe of a CJ-6. The rear seat was removed to make room for an 882 lb tank for aerial spraying (as well as 441 lb tanks in the leading edge of the wing centre section) or up to 1,764 lb of freight. The Haiyan A prototype first flew on August 17, 1985 and was produced as the Haiyan B topdressing and fire fighting aircraft and the Haiyan C two seat observation and patrol aircraft.
The exact number of CJ-6 and 6As built is uncertain but estimates range from between 1,500 and 2,000. Even though the vast majority were (and still are) used by the PLAAF, a number were exported as the BT-6 to Albania, Bangladesh, Cambodia, North Korea, Tanzania and Zambia. The CJ-6 is also starting to become popular in the warbird and classic aircraft fraternity with approximately 50 currently in private ownership worldwide, including five CJ-6As on the New Zealand register at the time of writing. The only real problem many owners have with the aircraft is people confusing it with the Yak-52. Although both aircraft share a common ancestor and look similar to the casual observer, the Nanchang CJ-6 is a completely indigenous Chinese design.
Text © 2002 Stuart Russell.
Power plant: One 212.5kW (285hp) Huosai-6A
Wingspan: 10.22m (33ft 6 1/2in)
Length: 8.46m (27ft 9 1/2in)
Max T-O weight: 1,400kg (3,088lb)
Max level speed: 297km/h (185mph)
Range: 640km (399miles)