Chapter 477

However, the central wing box Lin Guanghua took out this time is not a traditional small wing box embedded in the fuselage, but a top mounted central wing box placed outside the fuselage.

The advantage of doing so is to ensure the integrity of the engine room to a large extent, increase the volume of the engine room, ensure the loading capacity of goods, and give more flexibility to the transportation task.

At the same time, the large top mounted central wing box is also the largest fuel tank in the whole aircraft. Because of the top mounted central wing box, it does not need to consider the structural bearing problem of the whole cabin section, so it can be larger than the traditional embedded central wing box.

Although the appearance of the aircraft seems to have a sense of hunchback, the benefits of this kind of hunchback are obvious. It not only enables the wing to bear greater external forces, but also makes the selection of the wing more flexible and has greater bearing capacity. In other words, it can increase the fuel capacity of the wing tank.

With such a series of optimizations, even if the take-off weight of the advanced light transport aircraft is the same as that of yun-7 and an-26, the fuel carrying capacity is 1.5 to 2 times that of the former two. Coupled with the turboprop engine with a fuel consumption rate of 0.308kg/kwh, it is really not a problem that the advanced light transport aircraft wants to fly 5000 km.

It's just

"Lao Qian ~ ~" Zhuang Jianye closed the car door, rubbed his swollen forehead and said, "I understand your mood, but some things are urgent. Let alone anything else, the overhaul interval of d-50 test is 1860 hours. Do you dare to guarantee that it will be the same as the test bench when it is sent to the power plant?"

"This..."

Qian Qiang was said by Zhuang Jianye that he was speechless, and the data on the test bench was true and reliable, but the practical application was another matter. Sometimes the situation encountered was not taken care of by the test bench at all.

Of course, this is not the most important thing. The key is that the old problem that plagues the power of Tengfei aviation is that the axle is stuck. Even if many advanced composite materials are used, all kinds of Kaspersky are still there. Qian Qiang and others have not thought of a way to solve it. But after some attempts, none of them are effective. In the end, they have no choice but to maintain the status quo first.

Looking at Qian Qiang's silence, Zhuang Jianye reached out and patted Qian Qiang's thin shoulder: "in fact, Lao Lin's side is similar to your side. The top mounted central wing box has many advantages. Otherwise, how could the strategic transport planes of the United States and the Soviet Union use this structure? But from another point of view, there are no other countries that can make such a structure except the United States and the Soviet Union. Why? It's very simple. The first material can't keep up with the second process. "

Qian Qiang frowned. Although he was helpless, he still admitted that Zhuang Jianye was right. The structure of the top mounted central wing box proposed by Lin Guanghua is good, but this idea is just like Qian Qiang's desire to find a turbine blade material that can withstand the temperature before the 1600 ℃ turbine. There are many insurmountable gaps.

Firstly, the top wing box increases the weight of the whole aircraft structure and affects the flight quality and basic performance of the aircraft; secondly, as the most important main bearing structure of the aircraft, the strength of the whole component must be very strong.

The superposition of these two points leads to an irreconcilable contradiction, that is, how to find an excellent balance point to reduce the weight of the structure while ensuring the strength.

In this regard, the United States and the Soviet Union have found their own ways and applied them to their own strategic transportation and transportation, such as C5 "galaxy" and C141 "United star" in the United States, and An-124 and Il-76 in the Soviet Union have all applied the top mounted central wing box structure to varying degrees.

Even in Europe, there is a gap in this respect, not to mention in China.

In such a big context, even in the alternative, Tengfei airlines can't resist the impact of the environment. At most, it just touches the edge of the top mounted central wing box technology.

Even though there are many metal matrix composites that can be used, the extremely low production capacity and high price are the biggest obstacles to their large-scale use. In addition, a series of processing technologies of new materials also need to be solved, among which the most important one is the crucial electron beam welding process.

This welding technology, which is very important in aeroengine and aircraft manufacturing, is not available at present in Tengfei aviation manufacturing corporation. This is also the main reason why the old problems of Tengfei aviation power engine can not be solved and the top mounted central wing box can not enter the substantive research.

Because without the intervention of this technology, all the beautiful plans of Tengfei aviation manufacturing corporation can not be turned into reality.

The key to the success of the United States and the Soviet Union in the field of large aircraft is to master the manufacturing technology of large electron beam welding equipment.

Among other things, the wing box of the strategic bomber 160, the pinnacle of the Soviet bombers, was basically welded with large-scale electron beam welding equipment. Otherwise, the strategic bomber 160 would never have been so elegant and powerful.

"Don't do porcelain work without diamond. Do you think the three of you don't know what's going on? They have been working in various factories all the year round to study the equipment of other countries. They are not experts in any field, but they are also senior people. They are like a mirror in their heart. If they don't break it, they will give us face. "Qian Qiang still frowns and ponders. Zhuang Jianye adds with a bitter smile. Qian Qiang immediately raises his head and looks at Zhuang Jianye with depression: "so, we are at a loss this time?"

"How could it be?" Zhuang Jianye looked at Qian Qiang in surprise: "although the investment in aircraft has not come, but the engine and composite materials can also earn pocket money."

Smell speech Qian Qiang quite lost sigh tone: "that or suffer a loss, the Navy's an-26 only 15, alas ~ ~ ~ can only be regarded as pocket money."

……

The pocket money in Zhuang Jianye's and Qian Qiang's mouth is very painful in the eyes of the Navy and aerospace departments. The power and shaft horsepower of the d-46ml turboprop engine refitted for an-26 are roughly the same as those of today's an-26 engine, but the unit price is 224 yuan, which is 40% more expensive than the turboprop-5 of the same class.

As for the d-50 used for marine gas turbine, the price is as high as 3.76 million yuan, which is almost the cost of a small torpedo boat.

The carbon fiber reinforced aluminum composite materials ordered by the Aerospace Department are also not so good. At the price of 1500 yuan per kilogram, it costs 15 million yuan per ton, which is the sky high price in domestic materials.

The two departments said it was fake that they didn't have a pain in the flesh, but they still clenched their teeth, took out the stickers and cut off the money to take off airlines.