CJ-1 is a Chinese development of Russian 91RE1anti-submarine missile. As China imported the ASW and land attack versions of SS-N-27, Chinese military was satisfied with the performance but not the price. It was too costly to import every single version of SS-N-27 so China decided to develop its own versions based on two versions imported, and CJ-1 is developed from the solid rocket powered 91RE1 model of SS-N-27. Norinco was assigned as the contractor to develop the Chinese improvement of 91RE1, and the first improvement was to overcome the deployment limitation. The original Russian weapon can only be deployed on Russian Kilo class submarines, and cannot be deployed on the newly built domestic Chinese submarines with fire control system based on western origin. The Chinese version is also built to Chinese GJV289A standard, the Chinese equivalent of MIL-STD-1553B, so that the weapon can be deployed on both the Russian and western origins. The second improvement shared by all models of the Chinese version is the incorporation of modular design concept so that a variety of payload can be carried.
CJ-1 ASW weapon
This is the first member of the Chinese version developed from 91RE1. The main improvement is that in addition to the original Russian light torpedo carried in 91RE1, a variety of western light torpedoes and domestic Chinese light torpedoes based on western origin can be carried. The need for such improvement is because despite having much higher speed, the range of the Russian light torpedo such as APR-3E torpedo is too short. In contrast, western light torpedoes and their Chinese derivatives would have more than three times the range of their Russian counterparts, despite the slower speed they have. Although dubbed as an ASW missile, CJ-1 ASW weapon is not an ASW missile as it is often erroneously referred, because one of the requirements for a missile is to have guidance in its flight, and this is not exactly what CJ-1 ASW weapon has. The missile is fired into the general direction of the target submarine with only rather limited inertial guidance, and the true guidance does not kick in until after the payload, namely, the torpedo has entered water. As a result, the official Chinese term of Rocket propelled torpedo is a more accurate description for this weapon, and the developer classify the weapon somewhere between a fully guided missile and an unguided rocket. When the payload is a depth charge instead of a torpedo, the weapon is referred as ASW rocket. The depth charge that is much smaller in size and weight would also enable the maximum range of the missile to be extended by 60% to 80 km. Specifications:
Payload: a single depth charge or a light torpedo up to 400 mm diameter
Cruising altitude: ballistic trajectory
Propulsion: solid rocket
Guidance: inertial during flight
CJ-1 AShM
Instead of importing submarine-launched anti-ship models of SS-N-27 from Russia, China has developed its own version. To simplify logistics and to reduce operational costs, the anti-ship version is developed from the solid rocket powered CJ-1 ASW weapon, instead of the original turbojet powered Russian version. A variety of seekers are developed for CJ-1 AShM, including radar, imaging infrared, and TV while the flight path of the missile is modified to have a sea-skimming capability. The warhead comes in a variety of size, with the largest weighing around half a ton. Specifications:
The advantage of having CJ-1 AShM is that while having similar range in comparison to C-801 that is also powered by solid rocket motor, the warhead of CJ-1 AShM is more than four times larger, while when armed with smaller warhead, the range of CJ-1 AShM can be extended to over 60% to 80 km. The same advantage of CJ-1 AShM has over C-801 also holds in comparison to the turbojet powered C-802, and additionally, the solid rocket powered CJ-1 has another great advantage in that it is much easier and cheaper to maintain. According to Russian claims, 91RE1 can be put away and stored for three years, and this advantage is inherited in its Chinese upgrade. In contrast, any turbojet powered missile would require periodic maintenance in storage, thus increasing the cost.