Super military empire

"The rotors are indeed the same, but can it be ensured that all traces of processing are the same? Are the strengths the same when rotating? Moreover, the upper and lower rotors do not interfere with each other when they rotate..." Liu Yijiu waited The staff removed the screw connecting the propeller hub with the propeller blade.

Only by seeing something can he confirm whether his guess is correct.

Aerospace items are extremely delicate. Sometimes, if a mouse gets into the cabin, it may crash the plane; a sparrow flying high in the sky may crash the plane.

Even a small screw must not be careless.

If it was really those screws, then the plane fell this time is not worth it!

Liao Zhuojing's brow furrowed even tighter. If it was a screw problem, it would be a production quality accident.The strength of the screw is not good. If it is caused by the design, then the design, proofreading, review and other people have to bear the responsibility.If it is a problem in the production process, the front-line production workers, team leaders, quality inspection, production scheduling and even the production workshop supervisor must be dealt with.Moreover, they checked the records of various processes during the production process, and there was no problem at all.

If you start from the beginning, you have to start with the production of raw materials, starting with the raw material formula, material production process, and material production quality...

After Liu Yijiu arrived at the base, that is, in 1977, the entire Ninth Institute began to comprehensively promote the implementation of the seven-specialized technical agreement, including special personnel, special planes, special materials, special batches, special inspections, special skills, special cards or special lines.This is to find from the source after the problem is discovered, which link has the problem.

This scheme was originally Liu Yijiu's original national military standard in the world. In order to ensure the quality of military components and solve the problem of poor production quality during the ten-year turmoil.

The only difference is that, through Liu Yijiu's hands, the seven-proprietary technology agreement of this era is far more stringent than the 7905 technology agreement that appeared in the world in 1979 and the 8406 technology agreement made in 1984.

In the production of military products, no errors are allowed.

During production, it was just a matter of quality, but when used on the battlefield, it was the life of a soldier.

Therefore, Liu Yijiu used his world to improve several times, and combined with the current actual situation, in line with the current military production expertise agreement, it has been promoted in military factories nationwide.Just for production efficiency and production quality.

"Director Liu, the control in our production process is so strict, and the design has undergone layer-by-layer review. How could there be a quality accident?" Wang Yueshan rushed to the front and was immediately confused when he heard Liu Yijiu's words.

If the current situation arises because of a small quality problem, and the tens of millions they have invested in it are lost, then a bunch of people will be dealt with.

Even the director of this district, he will be involved.

Seeing Wang Yueshan with a nervous look on his face, Liu Yijiu shook his head, “I can’t be sure if it’s a quality accident. You can only tell by seeing things. The biggest problem may be that we didn’t consider too much when designing. When the two rotors are coaxial, the rotation of the two rotors in the opposite direction will offset the torsion. I never thought that if the design strength of the two rotors is not strictly calculated, they will eventually affect each other..."

Liu Yijiu is the chief designer, and he cannot even be responsible for every screw.

"Isn't there any problems with the previous computer simulation? The strength structure is the same..." Liao Zhuojing has never touched a coaxial twin rotor before.

Even the single-rotor tail rotor helicopters in China have not been dealt with, and naturally they will not have the energy to get involved in the more complex dual-rotor.

Whether it is the coaxial twin rotors used on the Z-91, the parallel twin rotors used by light aircraft, or the tandem twin rotors used by heavy helicopters, there is a blank in China.The operability of the dual-rotor is much higher than that of the single-rotor tail rotor, and the stability is much stronger, but the technical complexity is too high.

"We did not consider that when the helicopter rotor is rotating at a high speed, once the air compressor generates a surge phenomenon, the engine efficiency will drop due to the change in the intake air flow, and the power transmission will suddenly change. The two high-speed rotating rotors lose the kinetic energy for work. Driven by inertia, the lower rotor will go upward due to the lift of the upper rotor, and the upper rotor will go downward due to the pulling force generated by the rotation of the lower rotor..." Liu Yijiu said his inference.

This was originally a problem related to the strength of the helicopter's rotor blades, and then it turned into the most stressed position, that is, the strength of the screw at the connection between the rotor blade and the hub...

Deformation of the screw will cause the rotor to lose control!

Is this really the case?

We can only wait for the staff to remove the screws on the propeller hub.

Within a few minutes, a technician in his forties ran up to Liu Yijiu in front of them profusely, reporting helplessly: "Leader, the screw at the link between the hub and the blade. It has been completely damaged and cannot be removed..."

Upon hearing this, Liu Yijiu was relieved immediately.

There is no error in my own analysis.

However, Wang Yueshan and Liao Zhuojing looked at each other, revealing a weird and bitter question.

It is a very simple fault. They have been searching here for such a long time and they have not found any problems.

They didn't know that the screws were damaged, the helicopters had fallen off, and the propellers had broken off, and it was impossible for them to be at the most stressed position without problems.

They did not expect that it would be due to the sudden change in force during the flight, first caused by the deformation of the screw with insufficient strength.

If that happens first, the result will be completely different. This is the problem of thinking mode.

"That's the problem. No matter what method is used, the strength of the screw must be calculated, and then the force of the two rotors and the influence of the interaction force when the movement of the two rotors are changed..." Liu Yijiu said solemnly. Ordered.

If the problem is found, it must be solved.

"In addition, the engine must also be inspected. Why did the test run for more than a year without surging occurred, and the result appeared as soon as the sky. This matter must be found in which part of the problem occurred, and all Relevant persons in charge of, go back to the technical room for a meeting and let the technical backbones listen together. They will all stand alone in the future. Although this kind of problem is difficult to encounter, we can’t let it reappear if we encounter it. ..." Liu Yijiu said to Wang Yueshan and Liao Zhuojing who were beside him."And the technology and supervisor of the production unit..."

If problems are found, a summary meeting must be held.

This is a habit and tradition that any research team will have.

Technological progress is moving forward after constantly summarizing various failures.

Liu Yijiu found the root cause of the problem, and there is no guarantee that it can only continue production and test flight.But he can't wait for that time to make a summary now, because he has a headache for the thinking patterns of these staff.

Anyone, as long as they think from another angle, can actually find the problem.

Empiricism kills people, this is not a play.

The experience of single-rotor tail rotor helicopters is applied to this, and no one actually suspects that there is something abnormal.

Everyone thinks that there is nothing wrong with the phenomenon of air surging.

"Today we are summoned here, not to hold anyone accountable, but to sound the alarm for everyone. If you have to be held accountable, I, the chief designer, is the most responsible person. Because this is not considered in the design. Problem. However, after the accident, for as long as half a month, countless times of testing, encountered these problems, no one has to analyze whether this phenomenon is abnormal, or use the old thinking of the past to analyze the present The problem... Our past thinking mode should be fundamentally changed!" Liu Yijiu spoke very seriously to the hundreds of people underneath.

"The research on the Z-7 has indeed brought us a lot of experience, but what we are doing now is not a single-rotor tail rotor helicopter like the Z-7, but a double-rotor with tail rotor. This is a brand new topic. Even internationally, only the Soviet Union is currently engaged in the research of coaxial twin rotors, but without the tail. Here, I want to ask why we know that this is a brand-new design and there is no experience to follow. You are still using it. The previous Zhi-7 research experience and flight test experience judge the problems we are encountering now?"

Liu Yijiu said this, a little harsh.

The entire Zhi-7 research team bowed their heads.

They have been using the previous experience to carry out their current work.

"As early as 1977, the central government proposed to emancipate the mind, especially at the scientific and educational work forum in 1977, Comrade Xiaoping proposed to emancipate the mind, break the previous mode of thinking, and better contribute to the country’s four modernizations. Serve and contribute to the power of our scientific and technological workers for the country to catch up with the world's advanced level. The task of scientific and technological workers is to produce scientific and technological achievements and talents! Our task is to produce results and improve the level of national defense science and technology! Even the most fundamental thinking mode If we cannot change, how can we promote the development of our national defense science and technology work?" Liu Yijiu became more and more popular.

He shouldn't stand up for these things.

The whole country is now encountering such problems.

However, at this time in his Ninth Court, he had to bring it up.

In this meeting, the main leaders and technical leaders of several other districts participated. Liu Yijiu took this matter as the starting point to sound the alarm for other units.

Otherwise, in the end he will be exhausted, and this will still be the case.He has to deal with any problems...