Chapter 999: Fan Up! Fan Up! (First three chapters)
But we can't blame them for this reaction. In fact, Gao Zhendong knew in his previous life that after decades of trying his best on the V-type stabilizer, the stabilization effect only increased by 10%, at most 20%. Comrades, have you ever seen such a "swoosh" that increased 6-7 times like riding a rocket?

In addition to the early V-shaped combustion stabilizer, other forms of stabilizers have also been used in the modification of LYP-13, but in the end it ended up using the dune vortex stabilizer.

At this time, the comrades deeply realized that a theoretical breakthrough is the biggest breakthrough. Compared with patching up the old plan, a good theoretical breakthrough may bring about earth-shaking changes.

Of course, this does not mean that improvements based on the original foundation are useless. After all, in terms of difficulty, finding a suitable new principle may be much more difficult than making improvements, and even the improvement may not be that great.

However, from a development perspective, things are hard to compare. The lower limits may seem similar at first glance, but the upper limits are very different.

This incident taught them a solid lesson.

However, at this time, the comrades only had a vague feeling about this, but the effect of the dune vortex stabilizer was real and immediately shocked them.

The comrade in charge of the combustion chamber design even had shaking hands.

For Mr. Wang, combustion stability is only one of the indicators. If it cannot be improved, he will have to make do with it. It has been used like this for decades. This includes the Russians and a number of users of the early MiG-21. Before using the MiG-21SM, they were all using this thing with high surge incidence and unstable combustion.

By the way, even if the SM model is used, the combustion stability of the R-13 it uses still cannot be compared with this dune vortex stabilizer.

But for the comrade in charge of the combustion chamber, it is quite different. This is one of his main jobs. He knows there is a problem with the combustion but cannot solve it completely. Anyone who is engaged in technology knows how that feels.

"How can there be so much?" It's not that the comrades don't believe it, it's just that this thing is too much, more than expected.

Gao Zhendong smiled and said, "Well, that's all I have analyzed. The simulation shows that the good lean flameout characteristics of this stabilizer are not achieved by increasing the blockage ratio or the slot width, but by vortex stabilization, so it has such a good overall performance. This is why I named it the dune vortex stabilizer. The shape comes from the sand dunes, and the effect comes from the trapped vortex."

Well chosen, this is a good name! The comrades thought to themselves.

"Chief Engineer Gao, I'll take this article away, hahaha." said Mr. Wang.

As for publishing this article, it cannot be published. At this stage, I wish I could keep it secret as long as possible.

"Take it away, take it away. It was originally prepared for you." The sooner you get rid of it, the sooner you let it go. This matter was not originally within the scope of your job. It should be handed over to the person who is most suitable to play its role.

"Mr. Wang, do you think that if this engine is modified like this, what can it be used for?" Seeing the comrade in charge of the combustion chamber design putting away the materials as if they were treasures, Gao Zhendong turned to ask Mr. Wang.

"What is it suitable for? It's suitable for fighter jet power." Mr. Wang didn't understand what was going on.

Gao Zhendong smiled and said, "Boss Wang, have you ever thought of using it to do something else?"

In fact, in terms of power alone, especially military thrust, there is no essential difference between the LYP-13FI and the two turbofan medium thrust engines, the RD-33 of the Russians and the F404 of the Americans. The former has a military thrust of 45 kN, while the basic models of the latter two are 50 kN and 48.9 kN. However, the increase in afterburner thrust is larger, which are 66.7, 81.3 and 78.7 respectively. The significant increase in afterburner thrust is related to the advantages of the turbofan itself.

But the fuel consumption is completely different. The military thrust fuel consumption of the former is about 25% higher than the latter two. The maximum afterburner thrust fuel consumption is similar to that of the RD-33, but still 404% higher than that of the F18.

Although the turbofan will affect the high speed, it is still better overall. Moreover, if the turbojet with the same core engine is converted to a turbofan, the thrust will actually increase.

"Change to something else? Do you mean the turbofan?" Mr. Wang understood a little.

"Yes, that's what I mean. Mr. Wang, you should know the benefits of turbofans better than I do. They're great stuff!"

“But the R-11 is not suitable for turbofan modification, right?” Mr. Wang hit the nail on the head.

The R-11 itself is not suitable for turbofan modification because it has too many inherent problems.

Gao Zhendong smiled and said, "But if you modify it according to the improvements just now, wouldn't it be much more suitable than R-11?"

Mr. Wang thought about what Gao Zhendong said and slowly realized, hey, some of the biggest problems have just been corrected!
There are too few high-pressure compressor stages, the engine is surging, there are no good materials, and the lean flameout performance is too poor, the combustion is unstable, the flame stabilization system cannot meet the soft ignition requirements of the turbofan engine, etc. Weren't all these solved just now?
Although there are still many specific details, at least the basic conditions are in place.

Does this mean that if we think of a way, we can still modify it into a good turbofan engine? At least the core engine is guaranteed, which is much higher than the R-11. Gao Zhendong added: "Mr. Wang, in fact, the intake flow rate of this improved engine has reached a level close to 70kg/s. From a basic perspective, it is enough for a medium-thrust engine. Even if we sacrifice high-speed performance and increase the bypass ratio, we can get a greater improvement and directly get an engine that barely reaches high thrust."

If we can get an intermediate thrust of around 70 to 80 kilonewtons, it can barely be considered a high-thrust engine these days.

The turbojets and turbofans made from the same core engine have very different total pressure ratios and air flow rates. Apart from anything else, the fan, which is much larger, can take in a lot of extra air, which results in increased thrust and reduced fuel consumption.

"No fighter jet would use this kind of 'high thrust', right?" The high-speed performance has been sacrificed, and the fighter jet can't fly fast.

A typical example in this regard is the ball that is blown up into the sky. The engine thrust is great, but the high-speed performance... It can only sit at the same table with children in the fighter jet.

"But we have more than just fighter jets. We can think about it this way. We can make a small bypass ratio, not set too high requirements on thrust, and focus on fuel efficiency under the same thrust performance. We can also make a large bypass ratio engine specially prepared for subsonic aircraft."

Forget about turboprop engines and propfan engines. Some comrades are working on them, and Gao Zhendong knows that some of them are barely usable. And until Gao Zhendong traveled through time, he still didn't clearly distinguish the essential difference between turboprops and propfans.

"Well, your idea... is pretty good, it really works! We can even use this to make a turboprop..." I didn't expect that Mr. Wang's imagination is even bigger than Gao Zhendong's!
"This...isn't the business too big? Besides, there should be comrades working on similar engines, and there is no urgent need for them," said Gao Zhendong.

"Ah... this... seems a little bit." Mr. Wang also realized that this business was too big. It was all Mr. Gao's fault. He described the prospects too brightly and he fell into the trap accidentally.

After suppressing Mr. Wang's "dangerous" idea of ​​making a big move, Gao Zhendong suggested: "I think if everything goes well, it would be more appropriate to start with a turbofan with a large bypass ratio."

This suggestion puzzled Mr. Wang: "Why? The Air Force has already given us a preliminary research requirement and wants a medium-thrust turbofan engine."

Gao Zhendong knew that this was the last of the three levels and three types - the preliminary research of the medium air superiority fighter was already underway.

"I think there is a gap in the field of high bypass ratio and high thrust turbofan, but for medium thrust engines, there is the R-11 model with replacement materials." After the R-11F300 replaced its materials in China, the thrust increase was about 10 points, which can temporarily keep up with the research progress of medium-sized air superiority fighters. With good adaptability, replacing the engine is not a difficult problem.

However, Gao Zhendong also knew that this matter was not something that Mr. Wang could decide: "I'm just saying this. If you think it's appropriate, we can jointly submit suggestions to the Defense Work Committee and the Air Force. It doesn't matter if it's not convenient for you. I'll make suggestions when the time comes."

"In fact, there is no need to be so troublesome. The construction of the Third Front has begun. We have received notice that part of our institute will begin to be diverted to the Third Front." President Wang murmured.

Gao Zhendong then remembered that he had forgotten about this matter.

"Would you mind telling me where you're going?" He had no taboos when it came to asking questions. If the other party could tell, they would tell, and if they couldn't, they wouldn't tell. But he himself could definitely ask.

"That's not an inconvenience, Qianshan!"

Gao Zhendong chuckled and said, "That's fine."

"What you mean is, before the comrades who are relocating go there, we should first develop the modified turbojet model of R-11F300, and then after the construction over there is completed, we can build a turbofan on each side?" Gao Zhendong said.

Mr. Wang nodded: "I think this will work."

The engines these days are much simpler and can be developed faster. In fact, as far as Gao Zhendong knew in his previous life, it only took four years for the LYS-6 high-thrust turbofan engine to be developed from its proposal to its completion and the start of bench testing.

It was still a brand new engine, but it didn’t take that long. As for the difficulties in the aerospace industry later on, it was mainly because we were catching up. After spending almost 20 years catching up on 50 years of lessons, the situation is much better.

This is something that has a foundation, so it should be faster to modify. Not to mention that Gao Zhendong himself provided great help in terms of materials. He developed many things decades ahead of time.

Therefore, Mr. Wang and Gao Zhendong himself both felt that this matter was feasible.

"Okay, if that's the case, we can jointly report to the Defense Work Committee and the Air Force and get things done."

"Okay! Let's do it!" Mr. Wang was also unambiguous.

(End of this chapter)