(The tenth issue of Ordnance Industry Science and Technology magazine "Domestic Large Helicopter" brand new is on the market. Friends who like it, please pay attention to Ordnance Industry Technology News official account to purchase)
During the disaster relief process of the 2008 Wenchuan earthquake, helicopters shuttled through the mountains. Between them, a "lifeline in the air" has been set up, playing an irreplaceable and unique role. But at that time, it was mostly imported helicopters that played a major role. As the only domestic large-scale helicopter participating in earthquake relief, the Z-8 has performed well in rescue and disaster relief, but its service ceiling under full load is only 4,300 meters, resulting in insufficient plateau flying capabilities, making it difficult to perform on the Western Sichuan Plateau greater effect. China urgently needs to make up for the lack of independent support capabilities of plateau helicopters. It urgently needs to call for a helicopter that is truly born for the plateau and has full-area, full-time, and all-weather combat capabilities.
Letting domestic helicopters soar in the vast sky of the Qinghai-Tibet Plateau has always been the dream and pursuit of the Chinese people, and especially aviation people.
The Z-20 development plan was officially put on the agenda. In 2010, the Z-20 project was officially established, and Deng Jinghui was appointed. Model Chief Designer. The development of the Zhi-20 is a complex systematic project involving many departments, new technologies, high requirements, difficulty, and a long development cycle. Deng Jinghui knows very well that "key core technologies cannot be obtained by relying on alms," and key technologies must be conquered. , take the road of independent innovation. Under his leadership, the R&D team has made breakthroughs in rotor anti-/de-icing thermodynamic analysis, heating zone and control law design, heating component development, ice wind tunnel testing, and anti-icing spray tower testing through multiple rounds of optimization iterations and collective intelligence research. key technology, achieving zero domestic rotor anti-icing/de-icing technology The breakthrough has filled the gap in this technical field of domestic helicopters, completely solved the situation of being controlled by others, expanded the use envelope of domestic helicopters, and improved the helicopter's all-weather use and combat capabilities in areas prone to icing such as plateaus. It truly Made the Chinese people's "project to strive for success".
Overcoming rotor anti-icing and de-icing technology
To develop a helicopter with full-range, full-time, and all-weather capabilities, rotor anti-icing and de-icing technology is a top priority. As we all know, helicopters often see icing clouds during flight. The height of icing clouds is 0-5500 meters, and the height of icing cumulus clouds is 1000-7000 meters, which just covers the common activity areas of helicopters. Rotor icing is the most serious icing situation in helicopters. Supercooled water droplets in the atmosphere will quickly gather on the leading edge of the high-speed rotating rotor blades and condense into ice, which will change along the span and increase the uncertainty of icing. large, causing the aerodynamic shape to change and the lift-to-drag ratio to decrease, and the mass distribution of the rotor to change. The vibration caused by the change will put huge pressure on the engine, and it will also cause the main shaft to vibrate and be damaged when the ice cubes fall off, not to mention the destructive effect of the thrown ice cubes on the equipment on the aircraft. If the helicopter engine power is insufficient at this time, it will be very serious. It can easily cause a helicopter to crash and can be called a helicopter killer. Therefore, if you want to develop and build a helicopter with full-range, full-time, and all-weather capabilities, rotor anti-icing technology is a difficult problem that must be solved.
Before the development of the Z-20, none of our country's domestic helicopters had this capability. For a long time, only the United States and France had mastered technologies such as heating components embedded inside the composite blades, which are the core rotor anti-icing technology. For example, the United States' S -92, new Black Hawk, European EH-101 and Super Puma helicopters. Rotor anti-icing technology requires precise control of the thermal power density of the heating components embedded in composite materials. If the temperature is too high, the blades may be burned. If the temperature is too low and the ice cannot be removed, it may lead to catastrophic consequences. In addition, the heating components are buried in the Among propellers, the technical issues involved in ensuring the longevity and reliability of components while the blades are rotating at high speeds are very complex, and therefore have become a secret that is not passed down in the United States and France. In order to reduce development risks and speed up development, Deng Jinghui and his scientific research team initially considered cooperating with relevant institutions in a certain country, and the two parties reached an agreement on cooperation. However, when a cooperation agreement was formally signed in Beijing in February 2012, a certain country's company overturned its commitment on the spot. Faced with a sudden change of heart in a certain country, Deng Jinghui was unprepared, as if he had fallen into an ice cave.After calming down for a moment, he realized more firmly that key core technologies could not be obtained through cooperation and must be independently developed.
The development of the Z-20 is a complex system project involving many departments, new technologies, high requirements, great difficulty, and a long development cycle.
When forming the project research team, Deng Jinghui made it clear that the rotor anti-icing technology can only succeed but cannot Failure must not hold back the entire new aircraft project.
Fortunately, AVIC Wuyi in China has accumulated technology in wind vane anti-icing research and electromagnetic resonance icing annunciator, so AVIC Aviation Instrument Co., Ltd. (Wuyi) and AVIC Helicopter Research Institute jointly started the development. The research is mainly conducted in the Key Laboratory of Aviation Anti-Icing, because there are two YBF-02 instrumented ice and wind tunnels and icing climate chambers and YBF-05 ice and wind tunnels, which have excellent conditions. On this basis, Deng Jinghui's team has successively made breakthroughs in the collector ring power supply core component brush , conductive ring material technology, rotor anti/deicing thermodynamic analysis, heating zone and control law design, heating component development and ice wind tunnel test, anti-deicing spray tower test, and also added the design of de-icing intelligent control mode, and developed the XBJ-2 icing annunciator and CJB-1 icing signal The ice melt detection system, etc., step by step, finally conquered the anti-icing technology of helicopter rotors. After a large number of tests, it was shown that it can fully meet the anti-icing needs of domestic helicopters. In January 2018, it fully passed the verification, realizing the domestic rotor rotor anti-icing technology. The zero breakthrough in anti-icing and de-icing technology has truly made the Chinese a "competitive project" and completely got rid of the "suffering" dilemma of China's helicopter research and development and manufacturing being controlled by other countries for a long time.
In February 2018, Deng Jinghui and his scientific research team completed the last test flight verification experience on a snowy plateau with an altitude of more than 5,000 meters in the northwest, which he will never forget. He told reporters that in previous years, Chinese helicopters did not even dare to fly at an altitude of 3,000 meters. At that time, it was the first time to verify rotor anti-icing and de-icing technology in a real harsh environment. The risk was extremely high. If there were any mistakes or malfunctions, a crash or fatality would occur at any time. appears, and they have no choice but to face the difficulties. The flight team who had followed him for five or six years were not afraid to enter the cockpit, soared over the ice and snow plateaus without any distractions, and finally successfully completed the test flight verification. When the helicopter landed smoothly, he and his team were ecstatic, ran to the pilot, hugged each other tightly, and cried with joy. They can finally declare to the world with pride and pride: whatever European and American countries can do, China can do it.
Rotor anti-icing technology is the top priority in the development process of the Z-20.
was the first to adopt the fly-by-wire flight control system.
The development of the Z-20 involves the application of a large number of new technologies, of which rotor anti-icing is only one part. At present, new generation helicopters around the world have begun to apply the emerging technology of fly-by-wire flight control systems, including the American H-92, New Black Hawk and Russian Ansat helicopters. Compared with traditional mechanical flight control systems, fly-by-wire flight control can significantly reduce the weight of the helicopter and improve the pilot's controllability. It is of great significance to improving the safety performance of the helicopter, and therefore has become the development trend of the new generation of helicopters. When
was developed on the Z-20, there were no domestic aircraft models using fly-by-wire flight control, and there were very few examples abroad. Therefore, whether to use fly-by-wire flight control became the focus of debate. Faced with different voices and doubts, Deng Jinghui key Always have the courage to take responsibility and decide to adopt fly-by-wire flight control in one step. This is not a blind decision, but is based on a large number of past theoretical, software and hardware experiments.
In the early days of the application of fly-by-wire flight control system engineering, some people were worried that no pilot in China had flown a helicopter with fly-by-wire flight control. It was too radical to directly use a pure fly-by-wire flight control system. It was recommended to retain a backup mechanical control system to avoid Disruptive questions arise. Deng Jinghui led the R&D team through in-depth analysis and believed that the existing technical reserves are sufficient to support the application of a full-authority fly-by-wire flight control system on the model. At the same time, the backup mechanical control system will significantly increase the weight of the empty aircraft.In the end, he withstood the pressure and decided to adopt a full fly-by-wire flight control system without mechanical backup. He adopted a four-degree redundancy design to fully ensure flight safety. He also adopted measures such as step-by-step implementation and gradual release of authority to effectively reduce test flight risks. Through demonstration and verification, multiple rounds of optimization and a large number of flight test parameters, it has made breakthroughs in key technologies such as overall system design, control law design and development of steering gear , ending the history of no fly-by-wire flight control helicopters in our country.
In order to ensure sufficient flight power, the Z-20 engine uses my country's independently developed turboshaft 10
domestic engine
In addition, in order to To ensure sufficient flight power, the Z-20 engine uses my country's independently developed turboshaft 10. In 2017, the China Aviation Power Research Institute teamed up with more than a dozen units such as China Aviation Power Southern Company and the Power Control Institute to form a joint research and development team. Finally, the research and development difficulties of the turboshaft 10 were overcome and the power problem of the Z-20 was solved. According to media reports, the turboshaft 10 engine adopts an excellent design for high-altitude areas, which enables the engine combustion chamber to still operate efficiently and fully under low pressure/low oxygen content/low temperature conditions, ensuring that the engine has stable and continuous output. power. It is reported that the rated power of turboshaft 10 is 1600KW, and it can reach 2000KW in emergency output state. Not only is it far more than turboshaft 9, but it also greatly exceeds Black Hawk's T700!
It is worth mentioning that all components of the Z-20 are made in China, and the realization of localization means that the emergence of the Z-20 has truly enabled Chinese helicopters to have full-range, full-time, and all-weather flight capabilities.
