Recently, a domestic magazine released a flight photo of a new type of anti submarine helicopter with a domestically produced fuselage model labeled as Z-18FA. From its appearance and number, it is not difficult to see that this helicopter is an improved version of the Z-18F anti submarine helicopter. Judging solely from its appearance, the biggest improvement of this helicopter is the replacement of a new power compartment based on the Z-18F, which is basically identical in appearance to the domestically produced Z-8C/CJ power compartment. Therefore, it can be concluded that the Z-18FA, like the Z-8C/CJ, uses the domestically produced WS-6C new turboshaft engine.

Straight -18FA

At the same time, AVIC Changfei, the manufacturer of Zhi-8, also released a picture of Zhi-8B on its official account, which had replaced the imported engine with a turboshaft -6C engine. Since its power cabin appearance was the same as the early Zhi-8, according to the fact that the part of the power cabin replaced in this picture had not been painted, it was the first time to confirm that this was a helicopter replaced by Zhi-8B, rather than the early Zhi-8A helicopter. In fact, the hairstyle change of the Z-8B has been publicly reported multiple times, but it has not been confirmed whether it is the Z-8B hairstyle change or the early Z-8A.

The appearance of these upgraded Z-8 series helicopters indicates that the performance of the domestically produced new turboshaft-6C turboshaft engine can fully meet the needs of Z-8 series helicopters, and can replace imported engines. The replacement process is not complicated, thus eliminating the long-term dependence of Z-8 series helicopters on imported power systems!

The earliest Z-8 series helicopters adoptedThree replicas of the "Toubo Meka Turmo III C"The WS-6 engine of the turboshaft engine has a maximum takeoff power of 1100 kilowatts per unit. However, for China, which had never independently developed a turboshaft engine in the last century, the replication work was difficult. Compared with the original engine, the turboshaft-6 not only had lower power, but also had a significant gap in reliability and lifespan, and the overall cost was high. The engine also became one of the main factors limiting the development of the Z-8 series helicopters before 2000, which resulted in the Z-8 helicopter being unable to achieve stable and reliable production after being finalized for large-scale equipment use by the military. By 2000, the production was only 17 aircraft.

At the beginning of this century, China and Canada collaborated with Pratt&Whitney to develop the PT6B-67A engine specifically for the Z-8, utilizing its 1000 kW PT6B series turboshaft engine and incorporating some PT6C technology. The technical level of this engine is roughly close to the third generation level. Due to the use of mature engines for improvement and development, this engine not only has a maximum takeoff power of 1446 kilowatts far higher than that of the WS-6 engine, exceeding the typical 1300 kilowatt class engine, but also imported at a cheaper price than the domestically produced WS-6 engine at that time. Its reliability, economy, and lifespan make the WS-6 engine difficult to match.

This type of engine adopts axial intake instead of the forward intake of the WS-6, so the Z-8 equipped with this engine has modified the power compartment design, which is significantly different from the appearance of the early Z-8. With the use of this high-performance engine, the development of the Z-8 series helicopter quickly entered the fast lane, and more than ten models equipped with this engine were developed and produced for military and aviation units, with hundreds of installations. It was the only large-scale equipment imported by the People's Liberation Army from Western countries at that time, and because the engine was a military civilian universal equipment, stable supply could also be achieved in the early stages.

Although imported engines have always been used well, China has not forgotten the lesson of the Zhi-10 imported engine supply interruption back then, and the improvement and enhancement of the WS-6 have not stopped. As expected, seeing that the profits were almost made, Canada began to follow in the footsteps of the United States and tighten its exports to China. PT6B engines were indeed out of supply in the past few years! Fortunately, at this point, the improved version of vortex shaft-6C of vortex shaft-6 has matured, avoiding the recurrence of engine jamming.

Although the WS-6C still uses the WS-6 model, the internal modifications are very significant. After experiencing the complete independent development of 1000 kW class turboshaft-9 and 1600 kW class turboshaft-10 engines, China has accumulated rich experience in the development of turboshaft-6C engines. The overall level of the improved turboshaft-6C engine has been raised to the level of third-generation turboshaft-6C engines. After military trials, the response is basically equivalent to that of imported engines. Therefore, the plan to replace the Z-8 series helicopters with domestic engines has begun to emerge.

The maximum takeoff power of the improved WS-6C turboshaft is close to 1400 kW, and the continuous output power is close to 1300 kW, evolving from a 1000 kW engine to a 1300 kW engine with almost unchanged size and weight. With the advancement of processing technology, the reliability and lifespan of the engine have been greatly improved, and the output efficiency in high-altitude environments has been optimized, which is basically equivalent to imported engines, except that the maximum power is slightly smaller than that of imported engines, but the difference is not significant.

The Z-8C/CJ helicopter, which first appeared in 2017, is the first newly developed model to use the WS-6C turboshaft. These helicopters are equipped with the Marine Corps Air Brigade and Naval Aviation University for amphibious landing operations and training. At the same time, the first batch of Z-8B helicopters equipped by the Army Air Force also took the opportunity of major repairs to replace their imported engines with WS-6C in batches. Due to the relatively small overall size changes of the WS-6C engine, the early Z-8 power compartment design was adopted to minimize modification projects and reduce costs, and the Z-8B main reducer can be directly used without any modifications. The newly produced helicopter adopts a new powertrain design like the Z-8C/CJ, removing the transition fairing above the tail beam.

At present, the replacement of domestic engines is underway, including the Z-8B helicopter from the Army Aviation Corps and the Z-8WJ helicopter from the Armed Police Force. These helicopters are all early production equipment and mostly used in low altitude areas, with low requirements for residual power. Therefore, the slightly lower power of the WS-6C compared to imported engines will not have an impact. Due to the fact that naval aviation is mostly used in low altitude areas, all of its newly produced helicopters use the WS-6C turboprop. In addition to the newly produced Z-8C/CJs all using the WS-6C turboshaft, some newly produced Z-18Z early warning command aircraft and Z-18F anti submarine aircraft also use the WS-6C turboshaft, which is named Z-18FA according to the replacement type. Therefore, early warning command aircraft using domestically produced engines are likely to be awarded the Z-18ZA designation.

However, the equipment of the WS-6C still has some unavoidable flavors. Although this engine can basically replace imported engines, it does not help the future development of the Z-8 series helicopters. The AC313A helicopter currently under development may be the ultimate solution for using domestically produced power packs. A brand new high-power engine has been adopted on the AC313A, which is highly likely to be the WS-10 engine equipped by China for the Z-20 with international fourth generation engine level, with a power of over 1600 kilowatts. In order to adapt to the increased power of this engine, the installation method and main reducer of the engine have been completely modified to significantly reduce power loss! At present, the prototype of AC313A is being assembled and debugged intensively, and it is planned to make its maiden flight between May and June this year. After this new configuration matures, the development of the Z-8 series may usher in another explosion! Moreover, in the future, the Z-8 helicopter may no longer be called "Z-8"!