When the Chengdu Aircraft Factory was finally commissioned, J-7 production was assigned to this factory, allowing the Shenyang Aircraft Factory to concentrate on the J-8 fighter. The first Chengdu J-7 s rolled off the Chengdu Aircraft Factory production line in June 1967. These featured a number of improvements. Some examples were identifiable by a slight bulge at the fin/fuselage junction apparently housing some new equipment. Others had the brake parachute relocated to a cylindrical container at the base of the rudder. This arrangement had been introduced on Soviet versions from the MiG-21 PFS onwards; the Chinese designers were apparently aware of this. Nevertheless, the fighter retained the original forward-hinged canopy and single cannon.
The modified fighter was built in small numbers, seeing limited service with the PLAAF. When the PL-2 missile became available, it was issued to Chengdu J-7 units.
Since the efforts to copy the K-13 AAM as the PL-2 were taking longer than anticipated, the Chinese decided to bolster the Chengdu J-7 ‘s armament by reverting to the MiG-21F’s original twin- cannon arrangement, reinstating the port Type 30-1 cannon. Also, a variable air intake with a translating shock cone was introduced at last. The new version had a brake parachute container at the base of the rudder but retained the standard canopy and the original WP-7 engine. This time the changes were deemed sufficient to warrant a new designation, Chengdu J-7 I.
The production rate remained low and the new fighter was delivered to the PLAAF in very limited numbers. The Chinese iteration of the MiG-21F’s crew escape system where the canopy doubled as a slipstream shield during ejection proved extremely troublesome. The Mikoyan OKB had encountered similar problems with the system, but here they were compounded by problems associated with reverse- engineering the aircraft.
The Chengdu J-7 I’s service entry with the PLAAF coincided with the outbreak of the Vietnam War. Unlike the Shenyang F-5 (J-5) and F-6 (J-6), the new supersonic fighter missed its chance to fight in Vietnam due to the type’s teething troubles and the limited number available. Yet the J-7 I did indeed receive its baptism of fire during the Vietnam War. Between 1969 and 1971 the PLAAF J-7 I interceptors defending China’s southern borders destroyed six USAF combat aircraft intruding into Chinese airspace.
The Chengdu J-7 I only saw very limited service with the PLAAF and the PLANAF due to poor manufacturing quality, design flaws and unsatisfactory performance.
In 1974 the Chengdu Aircraft Factory began development of a further refined version designated Chengdu J-7 II. Its most obvious external identification feature was the new cockpit canopy optimised for the Type 2 ejection seat. The strongly convex canopy consisted of a fixed windshield and a hinged rear portion. Unlike the late MiG-21 versions, the rear canopy portion was hinqed at the rear, not to starboard.