. Erheng Bihuang is engaged in military production, so he looked at it and asked the General Administration, what are the requirements for materials when building large aircraft?"

When the chief engineer faced the Standing Committee member and the Executive Vice Premier, he was still a little psychologically stressed. After all, it was rare for such a big leader to be seen. However, when it comes to their professionalism, he naturally would not be frightened. "The metal and non-metallic materials used in large passenger aircraft were basically supplied by domestic supporting facilities during the development of the 10th period of the 20th period of the year. Nowadays, when developing large passenger aircraft, the situation is somewhat different from that of the time. First, after the development of my country's civil aircraft further integrates with the advanced level of the world, the materials need to pass quality control verification according to airworthiness standards. There are many types of materials used by an aircraft, and one process is required to complete certification. In another case, there is no need to limit the source of materials to the country. There is a channel to purchase materials from abroad. In this way, the material supply of civil aircraft in my country can be carried out in an orderly manner, and the improvement of domestic material quality can be carried out to pass the certification work. On the other hand, some materials can be purchased from abroad first.

The composite components used on large passenger aircraft are both a material and a structure. The scope of composite materials used in civil aircraft has undergone a gradual increase, so some composite materials will be used on large passenger aircraft in my country to gain experience in structural design and materials, so that the amount of them will be continuously expanded in subsequent aircraft models to reduce the weight of the body structure.

"Oh, that's it, Fan Heng nodded.

The reporter who accompanied him was very active in asking questions. A female CCTV reporter ran over and asked the chief engineer, "I heard that you told college students about wearing cotton jackets on planes. Can you talk to our audience?

Fan Wubing heard the sound very familiar. He turned his head and saw that Lan Lan, a reporter who was very familiar with Cui Qi on CCTV, couldn't help but smile at her. Unexpectedly, he was concentrating on interviewing the chief engineer and didn't look at him at all. It was really a bit like I was tying my true heart to Mingyue. However, Mingyue shining on the ditch. I couldn't help but touch my nose and laughed.

After hearing Lan Lan's question, the chief engineer felt that it was necessary to popularize science, so he smiled and said, "Oh. There is indeed such a thing. People need to wear cotton jackets when they are cold. The cruise height of large passenger aircraft is generally at an altitude of 9,000 to 10,000 meters. The average temperature in the troposphere of the atmosphere is below minus 50 degrees Celsius. As the saying goes, the height is cold. Since the entire fuselage of large passenger aircraft is basically one cabin, in terms of design, you have to wear a cotton jacket to keep the cabin warm."

Lan Lan asked, "So what is this kind of cotton jacket made of? Where is it placed?

The chief engineer replied, "The cotton jacket on the fuselage of the aircraft is obviously not made of real cotton. Because cotton is prone to absorb water and mold and gets old and wormy after a long time. Therefore, we chose glass wool made of inorganic glass submerged silk as raw material to keep warm as an inorganic substance. This kind of thing has a stable nature, both insulating and shock-proof, and is very light in weight. Therefore, the fuselage of the aircraft uses a quilt stuffed with glass wool, which is laid in the space between the skin of the fuselage and the decorative panels in the cabin."

He also said, "The entire cabin section and cargo hold section of the fuselage are wrapped in this glass wool quilt. They play a role in sound insulation and warmth. The cabin floor, because the cargo hold is below, is also in a pressurized insulation area, so in general, there is no need to be particularly insulated. However, under the cabin floor, the cabin floor is air-conditioned and is at low temperatures at high altitudes. Therefore, the cabin floor at the landing gear cabin is covered with resistance heating wires, which are powered on in the air to keep warm to prevent passengers from freezing their feet."

Lan Lan asked again. "The noise-proof design of large aircraft is not a gap in my country's design field. Can my country overcome this technological minefield?

Regarding this problem, the chief engineer seemed more serious. "I can say it responsibly. No. my country developed a large passenger aircraft, Yunshen, in the 1980s, adopted the sound insulation and warming method of glass wool quilts, so that the noise in the cabin during flight reached the international advanced aircraft level. The noise that passengers felt was very low during flight. The crew could talk to each other at will. I had personally experienced this when I was on Yunshen test flights. I felt it was the same as when I was flying around the earth in various foreign passenger planes. Now our material technology and motivation technology have made great progress, so this aspect will only be better and better. After the success of the large aircraft, it will become one of the most comfortable and safest models in the world."

"Thank you very much for your cooperation. Finally, I want to ask a very confusing question. Is the landing gear of a large aircraft also special? Lan Lan thanked the chief engineer and asked curiously.

“Well. This is indeed a good question.

When the take-off and landing weight of large passenger aircraft increases, the number of wheels needs to be increased to disperse the pressure on the aircraft on the runway, so that large aircraft does not need to require special second-gang and second-lane runways to take off and land six. The chief engineer explained. On the "people are familiar with" aircraft, one wheel is often installed under each landing gear pillar. The passenger aircraft with a slightly more passenger capacity is doubled. The number of wheels is installed under the main landing gear pillar. When the total take-off weight of the aircraft reaches more than 100 tons, the number of wheels needs to be further doubled. In terms of structure, a frame is installed under the landing gear pillar, and four wheels are installed on the frame."

Regarding this point, the chief engineer also asked everyone to visit the prototype model and gave some explanations. For example, on giant passenger aircraft like Boeing and Airbus, not only do they need to increase the wheels to disperse the ground pressure, but also increase the pillars of the buffer to absorb the impact energy when the body lands. The method used at this time is to increase the number of pillars of the main landing gear. Not only does it install a pair of main landing gear on the lower surface of the wing, but also add a pair of landing gear pillars on the abdomen of the fuselage. Under the buffer pillars of the wing landing gear and the belly landing gear, multiple wheels are installed with the frame.

Frame landing gear is also an important basic design type for large passenger aircraft. Similarly, in China, the test flight of Yunshi in the 1980s, it has successfully realized the frame landing gear design.

During the test flight, Yunshi has passed various tests from the zero-altitude Shanghai Airport to the world's highest plateau airport, the Tongga Airport, Tibet, and airports under different conditions in the north and southern Xinjiang.

In later international exchanges, the country also undertakes the design task of modifying four-wheel landing gears for foreign aircraft models. The results were praised by foreign aircraft manufacturers. Therefore, the frame landing gear of large passenger aircraft is a technology that has been mastered and a position that has been captured for the domestic aviation design industry.

"You just explained the story of our country renovating landing gears abroad. Which country is it for? The United States? When can I discuss it in detail?" Lan Lan's topic should be more critical. So he asked another question.

Engineer Lan naturally would not sting a few more words to cheer up the morale of the army, so he explained. "Last 1980s, when my country was assembling a US passenger plane, the main landing gear of the aircraft used two wheels, and the pressure on the ground exceeded the bearing capacity of some airport runways in my country. Therefore, the Civil Aviation Administration formally required the US passenger plane to be replaced with a four-wheel landing gear. That is to say, the frame landing gear must be installed at the lower end of the pillars of the landing gear. The project was cooperated with my country and the United States, mainly with China. After China completed the design, it was praised by the US. However, the modification project was not implemented on the aircraft due to the Civil Aviation Administration's revocation of the modification requirements. Despite this, my country's design of the frame landing gear has been recognized by the relevant design departments of the United States."

After hearing the chief engineer's words, Fan Wubing couldn't help but sneer, "Civil Aviation Administration. Hey."

Due to the disgraceful role played by the State Administration of Civil Aviation during the dismissal of the Y10 project, Fan Wubing now has a lot of resentment towards them, and Fan Wubing also believes that it is reasonable to follow the same lineage. Therefore, he has no doubt that there is still a very serious bureaucracy and mad style in the State Administration of Civil Aviation. After all, the annual large aircraft procurement case can be clearly seen there.

What is even more jealous is that there is no strict supervision mechanism in airports and ground construction. Basically, they say that they need to spend as much as they need to spend. The oil and water in it is even more outrageous. Although the Civil Aviation Administration does not show any signs of water, the loopholes in it are indeed amazingly large.

Fan Wubing once thought of taking advantage of the momentum to move the fatty figure of the State Administration of Civil Aviation. Unfortunately, my father is still in a situation where he has not yet established a stable foothold. If this re-election is successful, he will have the ability to operate it.

The problem of the State Administration of Civil Aviation has been solved, which will be of great help to its vigorous development of large-scale aircraft manufacturing and civil aviation transportation in the future.

Of course, the most important thing is that Fan Wubing has a deep resentment towards them.

Especially when visiting the overall blueprint for the design of the large aircraft project this time, Fan Wubing suddenly appeared. It turned out that so many key technologies were implemented in the YTN project team, which greatly shortened the expected design time. This item alone could save Fan Wubing billions of research funds and trial production costs of more than 10 billion yuan.

If Yun Shi had not been disbanded back then, would it take Fan Wubing to invest hundreds of billions of dollars to operate?
Chapter completed!