The name of China's C919 big plane is even more profound. "C" is the first letter of China (China) and the first letter of COMAC, the abbreviation of China Commercial Aircraft Co., Ltd., and also means that the company wants to communicate with European Airbus. The passenger car company) and the Boeing Aircraft Company of the United States have a high test rate in the international large passenger aircraft market, forming the ABC three-legged trend. The first "9" means long-lasting, "19" represents China's first large passenger aircraft with a maximum capacity of 190 passengers. The future model may be named "C929", of which "29" represents the maximum passenger capacity of this model. It is 290 seats. At the end of 2014, ARJ21-700 passed the airworthiness certification of the Civil Aviation Administration of China, and the airlines entered the commercial operation of the feeder route.
China's self-developed C919 large passenger aircraft was launched on November 2, 2015 at Shanghai China Commercial Aircraft Corporation. It was developed in 2008 and lasted for 7 years. It is scheduled to fly in 2016. Its main technical parameters: the basic mixed-level layout of 158 seats, the total length of 38.9m, the height of 11.95m, the wingspan of 35.8m, the standard range of 4075km, can fly directly from Beijing to Singapore, and is suitable for all domestic cities. Compared with Boeing B737 aircraft, it has the advantages of safer, lighter, more powerful, faster and more comfortable.
The nine parts of the C919's nose, front fuselage, center wing, and mid-rear fuselage are manufactured by domestic aviation industry companies such as AVIC. Flight control systems, wheel brake systems, auxiliary power units and navigation systems are provided by Honeywell.
The large aircraft engine was developed by the United States General Electric Company (GE) and the French Safran Group. It is bigger and more powerful than the existing Airbus A320 and Boeing B737 engines, but the fuel consumption is much lower than their cost. About 10% lower, carbon emissions reduced by 50%.
The C919 adopts China's self-developed supercritical wing to speed up and save fuel. Its important indexes such as acoustic resistance ratio, navigation characteristics and stall characteristics are superior to those of similar foreign models, and its speed is faster than them. The large aircraft cabin has a shock absorption system that can cushion the bumps. The inner wall of the cabin has a separate vent to better regulate the air pressure changes in the cabin. The intermediate position in the cabin is 12.7mm (0.5 inch wider than the international standard seat). ), so passengers feel more comfortable.
Application of aluminum in large aircraft
1. Selection of ARJ21-700 regional airliner
The selection of ARJ21 aircraft is mainly aluminum alloy. The quality of aluminum parts accounts for 75% of the net mass of the aircraft, 10% of structural steel and stainless steel, 8% of composite materials, 2% of titanium alloys, and other materials. 5%. The aluminum alloy used in the ARJ21 aircraft is generally the same as that of the B777 aircraft. The fourth generation high-strength and damage-resistant aluminum alloy with excellent comprehensive performance is used to manufacture the main structural parts; the lower wall of the wing is selected from the high damage tolerance type 2524-T3 aluminum alloy plate. With 2324-T39 alloy plate; the upper wing upper wall plate is made of 7150-T7751, 7055-T7751 alloy pre-stretched thick plate, which has high strength and corrosion resistance; wing beam, fuselage purlin, fuselage Frames, bulkheads, wing girders, ribs and spars are made of 7150 alloy extruded materials; alloy materials such as 7075, 7050, 2024 are also used, but not much.
More than 96% of the aluminum alloy parts are made of heat-strengthened 2xxx and 7xxx alloys, and only a few parts are made of 5052 alloy. Aluminum-lithium alloys have not been used in the manufacture of ARJ21-700 aircraft.
2. Selection of C919 passenger aircraft
In the selection of aluminum, a large number of traditional aluminum alloys are selected, such as 7075-T62, 7075-T73, 7050-T7451, 7050-T73511, 7050-T77511, 7050-T7351, 7050-T7452, 7150-T77511, 7075- T6, 7055-T7751, 7055-T76511, 7085-T7651, 7085-T7452, 2024-T42, 2504-T3, 2024-T3511, 2054HDT-T351, 2026-T3511, etc.; also selected a certain number of third-generation aluminum - Lithium alloy: 2198-T8, Al-Li-S4-T8, 2096-T8511, 2099-T83, etc., but the 7xxx series alloy is used the most.
The structural parts of the front fuselage, middle fuselage, mid-rear fuselage, nose and wing of the C919 are almost entirely made of aluminum, while the engine is hung, tail-tailed, flat-tailed, front fuselage front and rear. The frame, the rear fuselage rear section, the center wing, etc. are made of composite or titanium alloy forgings. C919 parts made of aluminum alloy (see Table 1).
In addition to the main components of the above sections are made of today's high-performance traditional 2xxx series and 7xxx series alloys, some important structures are made of third-generation aluminum-lithium alloys, some minor parts and functions. Parts are made of other aluminum alloys, such as air conditioning systems, oil pipelines, luggage racks, food racks, bathroom facilities, and so on. Therefore, the total working quality of the C919's aluminum work accounts for 65% of the total net mass of the aircraft.