Not long ago, with the test flight of the J-35, the controversy over China's first carrier-based fifth-generation aircraft was finally settled, but when the J-35 can form combat effectiveness is still full of variables, and now it is only a conventional take-off and landing test on land, and it also has to go through a series of stages such as ejection test flight, weapon test launch, and ship test flight.
J-35 carrier-based aircraft
Today, there are three powertrains available for the J-35:
The first is the RD93. It is the engine of the Dragon dragon, and it has also been used as the transition power of the Sword drone, the RD93 is a single-engine version of the RD33 engine, with a thrust of only 81 kN, and the thrust-to-weight ratio is only a pitiful 6.5, as the power unit of the MiG-29, it is generally only the technical level of the 1960s and 70s. If the J-20 can still be test flown with the 99M1 engine that year, then 10 years later, it is difficult for the J-35 to use the RD93 to accept, and with the RD93 push-to-weight ratio that is lower than the 99M1, not much can fly. Russia is developing a major modification of the RD93 model RD93MA, its thrust increased to 91.14 kN, but also has the ability to emergency air re-start and emergency oil release, but the RD93MA engine only entered the high-altitude platform test stage in July 2020, and also has to go through the flight platform and model test flight, the J-35 can not be counted on at all.
RD93 engine for the Dragon Dragon
The second is the "Tarzan" engine. Its predecessor is the "Tianshan-21" engine, is the Guizhou Aviation Group in the RD93 based on the development of the imitation model, numbered turbofan 13, its 3-stage fan using the overall leaf disc structure and variable diversion vane, single-stage high-pressure turbine using single crystal blades, single-stage low-pressure turbine using hollow air-cooled blades, but also the application of digital full authority control system, "Tianshan-21" engine performance has been greatly improved, even if its high-pressure compressor from 9 to 8 levels, the total pressure ratio is still increased from 21 to 23 The thrust was increased to 86 kN, the thrust-to-weight ratio was greatly increased to 7.8, and the overhaul interval was extended from 300 hours to 810 hours.
Turbofan 13 engine
On this basis, Guihang continued to work hard, and launched a better turbofan-13E, which uses a swept-forward fan to reduce the kinetic energy loss, so that the total pressure ratio is further improved, while the engine speed and air flow have also increased, and finally the thrust of the turbofan 13E exceeded 9 tons, and its name was also changed from "Tianshan-21" to "Taishan", "Taishan" engine has basically met the requirements of the J-35 test flight and even the installation, and has been tested by the Dragon Dragon, and then used for the double-engine J-35 is a matter of course.
The third is the turbofan 19 "Huangshan" engine. Although it has applied a lot of the pre-research results of the "advanced push" of that year, it is a new model designed for the 21st century, with a thrust force of 9500 kg and a thrust-to-weight ratio of more than 10, which is comparable to the F-18E/F F414 engine. However, the "Huangshan" engine only entered the ground bench test stage in 2019, which is slower than Russia's RD93MA, and it will undergo high-altitude platform and flight platform testing later, and finally it can be installed on the J-35 for model test flight. Obviously, the turbofan 19 is far behind the J-35, which has already begun test flights.
China's 9500 kg thrust class turbofan engine
Therefore, at this stage of the J-35 using turbofan 13E test flight is the most likely, which means that it will undergo a remake in the future, may think that the thrust of the "Taishan" engine of more than 9 tons has been almost the same as the turbofan 19, but it should be clear that although the performance has been greatly improved, the parent body of "Taishan" is still the RD93 engine, to "Taishan" here can be said that the potential has been exhausted, more than 9 tons of thrust is almost already the "ceiling". The new design turbofan 19 is completely different, its potential is far from being released, and its final improved thrust can even reach 12 tons of F414EPE, the latest model of F414, and 9500 kg is only the starting point of the turbofan 19.
But with a usable engine is by no means a big deal, greater difficulties are still to come, and like carrier-based aircraft, the boarding of its engines is also a big challenge. In order to achieve the goal of getting on the ship, the engine of the J-35 also needs to make a series of adaptive improvements.
The engine of the J-35 also has to undergo the test of going to the ship
First of all, the ship-borne engine should adapt to the "three highs" environment at sea. The ship-borne environment is much more complex and harsh than on land, and the carrier-based aircraft engines face the challenges of "three highs" of high temperature, high humidity and high corrosion. Not long ago, a British F35B fell into the sea because the cover of the intake tract could not be removed, but why should the intake tract be covered with a cover? A very important purpose is to prevent the engine from rusting and corroding in the environment of high humidity and high salt spray at sea. But just having a cover plate is not enough, after all, it is necessary to take off and land in this environment, and many of the materials of its engines still have to be redone, or sprayed with protective paint, so that the thrust-to-weight ratio of the shipboard turbofan engine will inevitably decline, such as the F14D F110-GE-400 engine, compared to the basic F110-GE-100, its thrust-to-weight ratio has plummeted from 7.07 to 6.16.
F-14D fighter
Secondly, the landing and re-flight put forward extremely high requirements for the handling and acceleration of the ship-based engine. The carrier-based fifth-generation aircraft must complete the landing on the aircraft carrier's 200-meter runway, which is only one-fifth of the land-based runway, plus the aircraft carrier itself will fluctuate with the sea surface, and the interference with the air flow is also complicated due to the existence of the island. In this case, the possibility that the 4 interception cables are not hooked is not small, which means that the carrier-based aircraft must be able to quickly open and re-fly. Two requirements are also put forward for the engine: one is to respond quickly and react quickly to the pilot's operation; the other is to reach the maximum speed in a very short period of time, and the afterburner must be reliably ignited, otherwise the carrier-based aircraft will have the risk of falling into the sea.
Blocking cables are not a panacea
The US Navy has made a hard rule on the basis of strict testing: the ship-based engine must be completed within 2.5 seconds from the normal entry thrust to the maximum thrust state, otherwise, the carrier-based aircraft will have the risk of falling into the sea, which is the experience summary of countless painful lessons.
And the domestic engine is precisely in the rapid restart and acceleration there is a big shortcoming, which is concentrated in the Taihang engine due to the poor starting performance of the air windmill and can not be equipped with the J-10 for a long time, just because the shipboard turbofan engine is quite difficult, the J-15 is equipped with the Al-31cep.3 engine made in Russia for a long time, it is the power system specially developed for the Su-33 that year, although the latest model of the J-15 has solved the problem of localization of the power, but it has not yet been installed.
The latest J-15
In summary, the J-35 must not only be prepared to use "Taishan" to complete test flights, ship and even batch installation, but also complete the transformation of the "Taishan" engine itself similar to RD33 to mi RD33MK. Fortunately, the "Taishan" engine is domestically produced, there is no problem of being subject to people, and it only needs to go through a remake to achieve a complete state, and the dream of the fifth generation of carrier-based aircraft Chinese is not small.