The two improved models of NK-8 are highly confidential of Runhua Industry, in order to prevent leakage to the greatest extent, these materials are never transmitted on the phone or by fax, after waiting for several days, Chen Geng finally learned about the improvement of these two engines:

"The first one is the one that is going to be used in military aircraft," Mr. Xie said: "The basic structure of the engine has not changed, it is still the two-stage axial flow structure of the NK-8, but the bypass ratio has increased from 1.02 to 1.57...... before."

“1.57？” For this newly adjusted bypass ratio, Chen Geng was a little strange: "Didn't you say 1.4 before?" How did it get to 1.57? ”

Chen Geng discussed with the engineers and designers of the Kuznetsov Design Bureau several times before, and everyone's opinion is that the requirements in many aspects such as balanced acceleration, high-altitude performance, fuel consumption, reliability and easy maintenance, etc., the bypass ratio is the most suitable between 1.41 and 4.47, as for which bypass ratio is finally determined, it can only be determined after precise calculations, how can the final result not be any number between 1.41 and 1.47, but 1.57?

Mr. Xie explained to Chen Geng: "That's the case, the engineers and designers of the Kuznetsov Design Bureau calculated and found that 1.52 is a critical point for performance improvement, and before 1.52, there is no way to achieve a good trade-off between fuel consumption and thrust." Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 ｉｎｆｏ”

Chen Geng suddenly, the meaning of Mr. Xie's words is easy to understand, before this thrust and fuel consumption increase is not a linear increase mode, for example, to increase a unit of thrust may require 1.1 or even 1.2 units of fuel consumption, but when the bypass ratio reaches 1.52, this situation has changed, becoming an equal and linear growth.

If you think about it carefully, you can also understand that the improvement plan of the NK-8, which expanded the duct ratio to 1.4, that the Kuznetsov Design Bureau told Chen Geng before, is actually just an estimate made by the engineers and technicians and designers based on their understanding of this engine, and more on the basis of their understanding and experience of this engine, and has not been accurately calculated, and naturally there is a considerable deviation from the actual situation.

Although I don't know why the final duct ratio is not 1.52, but 1.57, Chen Geng respects the decision of the designers and engineering technicians. Nodding his head, he said, "OK, since it's the result of discussion and trade-offs between design and engineering technicians, then do it, and what?" ”

Mr. Xie said: "There is also the fact that the compressor has changed from the previous 6-stage axial flow type to the 8-stage axial flow type, and because of the improvement of these two key indicators, the total boost ratio has also increased from the previous 10.8 to 14.2, well, there is also the control system from the previous mechanical hydraulic speed and fuel integrated control system to a digital control system with mechanical backup, and at the same time, a large number of years of experience and new technologies of the Kuznetsov Design Bureau have been applied.

After this series of improvements, the maximum take-off thrust of this engine has reached 134.67KN, which is much higher than the previous 127KN, and the cruising thrust has also reached 31.84KN, the cruising fuel consumption rate has been reduced from the previous 0.79 to 0.67, and the overall life is more than 4000 hours, and the Kuznetsov Design Bureau promises to help us gradually increase to more than 6000 hours. But ......"

Shrugging his shoulders, Old Man Xie said a little helplessly: "You know, these data are all Su Biao." ”

Is there any difference between the Soviet standard and the American and European standards? Of course there is, that is, in the case of the same data indicators, even if the thrust and fuel consumption rate are the same, Lao Maozi's products are also more fuel-intensive, do you say that it is magical?

Chen Geng was very open-minded, and said with a smile: "It's good to use some of them, but can you ask for more?" Before this, we were such a big country, but we couldn't even build a 90KN engine, let alone have such good stability and life. ”

"That's the same, with such a big thrust engine, what are we not satisfied with? The meal should be eaten one bite at a time, and the road should be walked step by step. Hearing Chen Geng say this, Old Man Xie also smiled.

At the beginning, what was the maximum thrust of the turbofan-8 turbofan engine that we imitated with JT3D as the prototype? However, even the turbofan-8, which was copied from the technical level of the Americans in the fifties and sixties, exceeded the industrial level of our country at that time, and although a few units were produced in the laboratory state, with the scientific and technological level and industrial level of our country at that time, there was no possibility of mass production.

Thinking about the fact that in just over ten years, our country has made such great progress in the aviation industry, and Mr. Xie really felt a little emotional.

After settling down, Old Man Xie continued: "As for the improved version that we intend to use for civil aircraft, the Kuznetsov Design Bureau has given 2 plans. ”

"2 options?" The previous plan was only a military modification and a civilian modification, but I didn't expect the Kuznetsov Design Bureau to finally come up with a military modification and two civilian modifications for a total of three schemes, and Lao Maozi was so enthusiastic? Chen Geng frowned: "This doesn't quite look like Lao Maozi's style." ”

"Aren't you poor?"

"How so? Oh...... I understand that the economic situation in the USSR is not very good right now. Chen Geng's face was abrupt, these guys took the initiative to change from the previous two plans to three plans, the reason is very simple, just one: three plans need more money and time.

Who said that Lao Maozi was real? They are like monkeys, they know very well that if they complete their work as soon as possible, maybe they will have to return to China, and returning to the Soviet Union will be tantamount to suffering? How can you stay so comfortable in China, not only the salary is high, but the living and working conditions are good, Runhua Industry eats and drinks well every day, of course, within the rules, you can stay as long as you can - if the rules are not suitable, then create conditions to modify the rules.

"It's not good, it's a mess! I heard about Estonia, Latvia, Ukraine, Belarus...... I heard that there are still several union republics making trouble there for independence, the internal chaos in the Soviet Union, and I heard that it is a problem for the common people to eat, what do you say this is called? As a person who came from before the founding of the People's Republic of China, Mr. Xie deeply knows how rare a unified and peaceful country is for ordinary people, and because of this, he is particularly annoyed by the current situation in the Soviet Union: "I can't figure it out, isn't it good to live honestly?" It has to be noisy! People in troubled times are not as good as a dog in the peaceful era, don't these people understand? ”

"How could they not understand? They just understand it too well," Chen Geng sneered and said, "But it's not messy, how can some people take advantage of the fire?" What's more, whether those ordinary people can live a good life and eat and drink spicy food, what does it have to do with these careerists and conspirators? I think ah, these people think that the more chaotic the country, the better, it is better to toss the Soviet Union away, as long as I am fat alone, Lao Tzu cares about the life and death of others! After a pause, Chen Geng said again: "What's more, one"

"Alas!"

How could Old Man Xie not know that Chen Geng was telling the truth? In the end, the anger in his heart turned into a long sigh: "These bastards, let's die, sooner or later they will regret it...... Let's not talk about these troublesome things, let's talk about these two engines. ”

Chen Geng responded: "Hmm."

Mr. Xie: "According to the old Maozi, the first engine is designed for the MPC-75 type of aircraft, this aircraft does not need too strong power, 100KN to 110KN thrust is enough to meet the use of the entire MPC-75 series of aircraft, and because it is a civil aircraft, it does not need to fly too high, so the focus of improvement is the economy, reliability, easy maintenance and service life of fuel consumption."

All the improvements were made around these points, and the key indicators that were finally determined were the expansion of the bypass ratio to 3.2 - both civilian improvements were 3.2 - but the combustion chamber was significantly modified, reducing the original 139 fuel nozzles to 96, which was used to reduce fuel consumption, and of course, the fuel control system was changed to a digital system with mechanical backup.

After such improvements, the thrust of this engine is 110KN, which is a slight increase from the 107.88KN of the NK-8-4 we introduced, but the cruising fuel consumption rate has been reduced to 0.54, according to the old Maozi, which is basically equivalent to the fuel consumption of the American JT8D-200 series engine. ”

Equivalent to the fuel consumption of the American JT8D-200 series turbofan engine? Chen Geng grinned when he listened.

With the experience of the improved military version with a bypass ratio of 1.57, he did not wonder why this civilian type was not the 2.2 that was said before, but ...... As the engine equipped with the early model of the Boeing 737, the Americans no longer use the JT8D series, okay?

The JT8D-200 series is just a small bypass ratio engine with a bypass ratio of less than 2, but your improved NK-8 is a medium bypass ratio turbofan engine with a bypass ratio of 3.2, and the fuel economy is not as good as that of the Americans? Is......

Let's say something, okay?