In fact, it is just a technology. The role of a large aircraft project is also not bad.

Assuming the successful test aircraft model, domestic production will definitely bring about a significant improvement in the manufacturing level of domestic enterprises. After the prototype flies along the domestic route for a week, the price of imported large aircraft components will be estimated to drop by more than 30%.

If the prototype of a large aircraft can fly to the United States and then fly back, it is estimated that the price of imported large aircraft components will drop by more than half, which means that the import cost will be greatly reduced, which is a very low cost. From this point of view alone, there are also research strategies with great economic benefits.

This speculation is not a dream, but a real fact, because at present, large aircraft are an absolute monopoly, and the prices are not transparent. Even if they are transparent, the labor and resource costs abroad are very high. If domestically produced, it is estimated that the domestic market will only need one-third of the foreign cost to produce the finished products of large aircraft, which will definitely bring huge impacts on large aircraft manufacturers such as Boeing and Airbus.

Of course, the ones that were hit the most were not foreigners, but a group of people from the State Administration of Civil Aviation. As well as the people in charge of large aircraft procurement plans, although these people have low positions and are mostly department-level departments and departments, the large amount of US dollars lost by the country because it does not have its own large aircraft are basically flowing out of these people.

As we all know, as long as there is a purchase, there will be rebates, and the proportion of this rebate is quite large.

If there are the most unhappy people now, these are the people.

The leaders of the China Aviation Manufacturing Group Corporation "Si Du is different, and a group of leaders in Lingxi Province are naturally quite excited. After all, the landing of this large project base in Lingxi will bring considerable influence to Lingxi Province. In the future, Lingxi's economic development will largely depend on the pull of the large aircraft project.

The cadres and employees of the group company also felt a little moved. It was so difficult to deal with when the state supported it in the past. Now, after changing to a private boss, it was easy to build it. The effect was pretty good. It is impossible to say that there were big problems in the past system. Brother Ling’s personal will often override national interests, which is very abnormal.

If there had been such an open environment, China's large aircraft manufacturing technology would have been better than that of Americans.

"It's not too late to catch up now, I'm afraid I'll retreat if I don't move forward," said an old engineer who was responsible for leading everyone to visit with some emotion.

Everyone agrees deeply about this, just like domestic computer technology, it was also ahead of the way. Now it has been dumped in Java? This is the same truth.

Fan Heng, Fan Wubing and others also visited the model area and three-dimensional animation design effect demonstration.

Large passenger aircraft need to cruise for a long time at an altitude of 9,000 to 10,000 meters, with high subtones. Therefore, the wings generally use swept wings with a large aspect ratio, with a sweep angle of about 35 degrees. In order to improve the efficiency of the wings to increase the lifting of the wings during the take-off and landing stage, large passenger aircraft usually use full-span leading edge flaps or slats, while double-slit or triple-slit flaps are used at the trailing edge, and steerable spoilers are also used on the wings.

This spoiler has many functions, which can assist the ailerons in the control of the aircraft rolling, and can also be used as a drag plate when the aircraft is reduced. In addition, it can also be opened as a lift plate after the aircraft wheels touch the ground, so that the aircraft lands firmly and steadily on the runway to prevent the aircraft from jumping back.

Therefore, the auxiliary surface on the wing of a large passenger aircraft is not just four (two flaps and two ailerons), but fifty. These fifty auxiliary surfaces must be designed to solve the problems of function, structure, manipulation, and vibration. This is a special area of ​​large-scale aircraft design.

However, these structural characteristics have been realized on the first large passenger aircraft developed in China on the 10th, which saved a lot of time and energy at this time.

The main feature of a large passenger aircraft fuselage is that when flying at high altitudes, the vast majority of the fuselage is an internally pressurized pressure vessel. This determines that the section of the fuselage is preferably circular, because the container with a circular section is most favorable to bear internal pressure. Sometimes, in order to increase the cabin volume, a double-circular shape of 8-shaped section is used, so that the upper and lower parts are composed of circular shapes, and the middle is pulled by the beam of the floor, which is also ideal for stress.

At the rear end of the cabin, the web of the frame is subjected to great outward pressure. If it is designed as a sturdy flat plate to hardly resist the pressure, the structure will become very heavy. Therefore, the rear end of the cabin is often designed as a spherical shape, so that less material is used and it is conducive to withstand pressure. This requires that the basic section of the fuselage, whether in a circular or non-circular design, should be shrinking into a whole circle to facilitate the installation of the spherical frame.

In this way, the doors and windows in the cabin become openings in the pressure vessel.

Therefore, the design of door frames and window frames must make the stress concentration caused by the openings well dispersed. Large passenger aircraft have about a hundred portholes, and should design a basic window frame in a form. The doors of the cabin must be without thresholds. This is to ensure that if the aircraft is taxiing on the surface, passengers must be able to successfully pass the cabin door and use an emergency slide to leave the cabin in the shortest time.

On the other hand, at high altitude, the cabin door should be able to safely withstand the pressure in the cabin, and it should never be ejected by the internal pressure like when opening the bottle plug. Therefore, the locking mechanism of the cabin door should be designed to be safe and reliable. Moreover, there should be a clear sign printed inside the door to remind passengers not to move the handle of the door during flight. This is why.

The passenger seats in the cabin are fixed on the slide rails mounted on the floor beam. Therefore, when the aircraft flies in the air, the seat position is very fixed, and can withstand the impact of various landing situations and protect the personal safety of passengers.

However, between each flight, if you want to adjust the position of the seat, such as adjusting the size of the first class cabin, you just need to move the seat on the slide rail. This not only meets the needs of various flexible adjustments during the flight, but also ensures safety during each flight.

This design was adopted in the YTU aircraft developed in China. During the test flight, the seat layout in the cabin and the installation of test instruments were adjusted between flights according to different needs. This adjustment was actually very convenient.

In fact, the most critical technology is still motivation technology, which is a key issue for China to build large aircraft. Fortunately, it has been solved now. However, the effect and whether it can withstand the test of a long period of time still need further experiments.

In the international industry, whether it is developing Chinese civil aircraft, Boeing, or European Airbus aircraft, they are all going to buy motivations from manufacturers around the world to match the aircraft. In fact, according to the previous idea, when developing new large passenger aircraft, they will first purchase motivations from world-wide motivation suppliers.

In the composition of the aviation industry, the aircraft model is generally the top of the pyramid. In today's open world pattern, many people believe that the exhibition of the domestic aviation industry needs to occupy the commanding heights from top to bottom, and the exhibition of the aircraft model is to drive the overall situation. As for the subsystems that form various parts of the aircraft, supply can be obtained through a fully-compliant method, instead of laying the foundation stones of the pyramid from bottom to top, and then showing the aircraft model.

Aviation motor is a very complex, very precise, high-turn, high-stress, and high-temperature equipment. Technically, it can be said that it is at the top of contemporary mechanical products.

In the past, when we were developing the YTF, we had two methods of motive supply at the same time. While developing domestic motives, we also purchased motives from foreign suppliers to use them and compared them in terms of effects.

Currently, the domestic high-power aviation motor developed by China Aviation Manufacturing Group Corporation is the aviation motor with the largest thrust developed in China in recent years. This type of motor has undergone strict ground interviews and has been installed on the aircraft for air test flights. The effect is still good. It is also constantly being tested and improved. We strive to improve day by day, and we will derived various models of special aviation motors.

During the YTF test flight that year, the developer considered that if the aircraft and the motive were newly developed, it would be difficult to determine the reason if some data deviated from normal during the test flight. Therefore, the initial stage of the YTF test flight was equipped with the motivation purchased from the world's motive suppliers. As a result, the domestic aircraft and the motive were tested separately. The next step should have been to use Chinese aircraft to install domestically produced motors to test flights, but unfortunately, the YTF project was permanently shelved for no reason and the test flight was stopped.

During the visit, Fan Wubing also had a problem, that is, in terms of the overall layout of the entire aircraft, the motives of some large Russian aircraft are very close to the fuselage, but the large aircraft project models we designed ourselves are not much the same. What are the different considerations?

The company's chief engineer explained to Fan Wubing. "Mr. Fan raised this question very well. The Soviet Union's first jet passenger plane was to install the motive at the wing root, which made the structural force transmission design of the installation motive and the arrangement of the system pipelines very troublesome, and the maintenance motive is difficult. The biggest problem is that the noise of the motive jet will impact the fuselage and cause strong sound waves to disturb the passengers in the cabin. What's more serious is that the bulkhead of the pressure cabin is acoustic and shock-shattering and easy to cause accidents. Therefore, this wing root motive layout was adopted by some European countries in the early days of jet passenger planes, but it was quickly abandoned."
Chapter completed!