The first flight of C919 domestic large aircraft was successful. Here are the ten questions you want to know most.
Xinhua News Agency, Shanghai, May 5th? Question: The first flight of C919 domestic large aircraft was successful. Here are the ten questions you want to know most.
Xinhua News Agency "Xinhua Viewpoint" reporter Jia Yuankun
On the 5th, China’s first trunk civil aircraft C919, which has completely independent intellectual property rights and is developed according to the latest international airworthiness standards, successfully made its first flight.
C919 has received 570 orders from all over the world. This large aircraft has promoted the development of the domestic aircraft manufacturing industry chain and achieved a major historical breakthrough in China’s aviation industry.
Here are the ten questions you want to know about C919:
1. Why does C919 have China’s independent intellectual property rights?
The full name of C919 is COMAC 919, which is the abbreviation of China Commercial Aircraft Corporation, the main manufacturer of C919. "C" is not only the first letter of COMAC, but also the first letter of China’s English name "China", which shows that the large passenger plane is the will of the country and the expectation of the people. The first "9" means "everlasting", and the first "19" means that the maximum capacity of C919 passenger plane is 190 passengers.
For such a complex product as a large aircraft, the overall design is extremely important. Without the overall design, even if the world’s best engine, fuselage, flight control, telex and so on are combined, you can’t get a flying plane. Wu Guanghui, the chief designer of C919, said that C919 is a trunk aircraft designed independently by China, and it has completely independent intellectual property rights in terms of the overall design of the aircraft.
The outer "shells" such as nose, fuselage, tail and wing come from China’s Chengfei, Hongdu, Shen Fei and Xifei enterprises, while many other key parts come from foreign enterprises. It is reported that global procurement is a major feature of civil aircraft manufacturing, and suppliers of Boeing and Airbus also come from all over the world. However, a major mission of C919 is to promote the development of domestic civil aircraft industry chain, and it is believed that more and more parts will come from China enterprises.
2. Why isn’t the C919 equipped with a domestic engine?
At present, China does not have the ability to produce engines suitable for civil large passenger aircraft, and the engines of international civil aircraft manufacturers are also purchased from suppliers.
At present, the international civil aviation engine manufacturers mainly include Rolls-Royce of Britain, GM and Pratt Whitney of the United States, Snecma of France, and IAE and CFMI with multinational cooperation.
Of course, it is best to use engines from China, but the development of civil aviation engine industry can only be driven by large aircraft. Without a big plane, there will be no demand, and there will be no platform. This is the relationship between the industry leader and the industrial chain.
3. How is the security of C919?
Wu Guanghui said that the C919 large passenger plane is designed according to more advanced technical standards, adopts the most advanced power, avionics, flight control and other systems provided by world-class suppliers, and is designed and produced in full accordance with international airworthiness standards, so its safety is fully guaranteed.
In the end, whether the C919 aircraft is safe or not is not the decision of its manufacturer, China Commercial Aircraft Corporation, but the airworthiness certification of the Civil Aviation Administration of China. In other words, the flight mission of civil aviation can only be carried out if it conforms to all aspects of the test of aircraft by the Civil Aviation Administration of China, and the safety test is the most important.
4. Which airlines will meet C919?
C919 has received 570 orders from 23 companies around the world. At present, many airlines such as China Eastern Airlines, Air China, China Southern Airlines, Hainan Airlines, Sichuan Airlines, Hebei Airlines, Happiness Airlines, Germany Puren Airlines, Thailand Metropolitan Airlines, and many financial leasing companies such as Ping An International Financial Leasing, ICBC Financial Leasing and Bank of Communications Financial Leasing have purchased C919. Liu Shaoyong, chairman of China Eastern Airlines Group Corporation, said: "China Eastern Airlines has become the first user of C919. China Eastern Airlines will strive to operate this aircraft well and have full confidence in domestic large passenger aircraft."
5. Can C919 be favored by airlines?
For airlines, economic and environmentally friendly aircraft have strong profitability; For passengers, riding comfortably can win the favor of passengers.
The C919 large passenger plane is designed to reduce weight and drag, and the advanced new generation engine LEAP-1C is adopted, which greatly reduces the cruise fuel consumption rate (SFC) and has obvious economic competitive advantages. Leap-1C, an advanced new-generation engine, is adopted. The outfield noise meets the fourth-stage noise requirements of ICAO with a margin, and the emission of nitrogen oxides is reduced by 50% compared with the requirements of ICAO CAEP 6, which is highly environmentally friendly.
The large fuselage of C919 passenger plane will provide more space for passengers. At the same time, it will provide high-quality fresh air with high-efficiency air filtration system, and the cabin lighting will adopt humanized scene lighting design to give passengers a warm and considerate comfortable environment.
6. What new materials are available for C919 to make the aircraft light and long-lived?
Compared with traditional aluminum alloy, Al-Li alloy has higher specific strength and stiffness, and stronger damage tolerance, fatigue resistance and radiation resistance. The use of Al-Li alloy can greatly improve the life of aircraft.
Wu Guanghui introduced that C919 has established the material specification system, design allowable value system and manufacturing process specification system of Al-Li alloy through a lot of research and development and verification tests. The third generation Al-Li alloy is applied to the fuselage skin, stringer and floor beam structure of C919, and the consumption reaches 7.4% of the weight of the fuselage structure.
At the same time, breakthroughs have been made in the application of composite materials. The application of composite materials has realized the integration and lightweight of the airframe structure, and the amount of composite materials has reached 11.5% of the airframe structure weight. It is the first time to use composite materials in the main load-bearing structure, high temperature area and pressurization area of civil aircraft in China.
Titanium alloy has been applied in the central flange, engine suspension, spherical frame flange, lappet wing slide rail, vertical tail butt joint and other parts. The amount of titanium alloy reaches 7.3% of the structural weight of the machine body.
7. How does C919 apply 3D printing technology in the manufacturing process?
C919 successfully applied 3D printing titanium alloy parts for the first time. Titanium alloy 3D printed parts have been successfully applied to the complex parts of C919 hatch, and their mechanical properties are obviously higher than those of the original castings, which effectively shortens the delivery cycle of the parts and quickly responds to the optimization changes of numerical simulation. The special raw materials and product specifications for titanium alloy 3D printing were established, which effectively ensured the product performance requirements.
8. How awesome is the "supercritical airfoil" of C919?
There are many major technological breakthroughs in the design and development of C919, such as the design of supercritical airfoil. Zhang Miao, deputy chief designer of C919 model of Shanghai Aircraft Design and Research Institute, said that supercritical airfoil can reduce aircraft drag, improve aircraft performance and help reduce fuel consumption. The first time we independently designed supercritical airfoil, it reached the advanced level in the world and was recognized by international peers.
9. What should C919 do after its successful first flight?
After the first flight is successful, C919 will be transferred to the airworthiness forensics stage. Airworthiness certification is the management and technical realization process to ensure that the aircraft meets the minimum acceptable safety standards (airworthiness standards) formulated according to public requirements: the aircraft must be designed according to airworthiness requirements; There must be a suitable system to ensure that the aircraft design meets the airworthiness requirements; The applicant must show the CAAC that its large passenger plane meets the airworthiness requirements by means of calculation, analysis, inspection and test. Only products that have passed airworthiness examination and verification and obtained airworthiness certificate can enter the market.
10. How will C919 drive industrial development?
Jin Zhuanglong, Chairman and Party Secretary of China Commercial Aircraft Corporation, said that China’s civil aviation industry chain driven by C919 large passenger aircraft has great potential. With Shanghai as the leader, 22 provinces and cities including Shaanxi, Sichuan, Jiangxi, Liaoning and Jiangsu, more than 200 enterprises and nearly 200,000 people participated in the development and production of large passenger aircraft projects, forming an industrial chain, a value chain and a innovation chain. Promote the establishment of 16 joint ventures in avionics, flight control, power supply, fuel and landing gear, and upgrade the supporting energy level of China civil aircraft industry.
This has not only significantly improved the basic outlook of China’s civil aviation industry development, but also forged an industrial chain with great potential for China’s economic transformation and upgrading.
In the future, with the promotion of large passenger aircraft projects and the batch production of jet aircraft in China, this industrial chain will gradually exert great economic potential.