On the other side, Chengdu.

Chen Nian sat in the office, looking at the thick pile of scratch paper in front of him with a sad face.

As early as a few days ago, he had already entered a normal working state, and now he spends all his time on the theoretical analysis of the two-stage counter-rotating lift fan, in addition to the fixed study schedule every day.

It has to be said that this is an extremely complex job.

Although the F-35's fuselage design and center of gravity data have been obtained, it is still difficult to deduce the accurate design data of the fan arranged behind the seat based on these things.

So, there is only one thing he can do:

Refer to similar flying machines as much as possible and look for clues from them.

During this period, Chen Nian consulted a large amount of information, but in fact, there were very few useful ones.

In fact, the world's first vertical take-off and landing fighter appeared in 1950, but the "vertical take-off and landing" method of that thing is to directly let the engine thrust be greater than the engine power, so that the plane can take off upright, which does not help Chen Nian's problem.

Similarly, the second-generation STOVL, which was equipped with additional take-off and landing engines, and the third-generation engine tilt, were also obsolete and had completely different design logic.

The only thing that works is the fourth-generation dual-mode STOVL, but this thing. Only the F-35 has it.

Chen Nian felt as if he was stuck in a dead loop.

After a busy week, he made no progress on his theory.

So, he secretly made up his mind:

If you're still stuck here within two days, then you can use the plug-in directly.

The reason why he has to set the target to two days later is because according to his current source point growth rate, he can basically save enough to analyze the source point of the core technology of the two-stage counter-rotating lift fan in about 10 days.

If you continue to spend it, you won't have enough time to study, which is equivalent to a net loss of 0.18 points per day

Thinking of this, Chen Nian couldn't help but sigh.

Reluctantly, he pushed away the mess of paper, stood up and walked out the door, wanting to get a few breaths of fresh air.

Unexpectedly, as soon as he went out, he bumped into Yang Wei, who happened to be looking for him.

"Chen Yunyong has done it over there!"

Hearing his words, Chen Nian was overjoyed.

"Done? How? When will it be in place? ”

"I exchanged the EC-130H, speaking of which, this matter is rooted in it, and it is still your credit."

"It is estimated that it will be in place next month at the latest, and a group of experts in the field of aviation will come with him at that time, starting from Shanghai, passing through AH, and flying over by military plane."

"What's the main area?"

Chen Nian continued to ask.

"There is everything, engaged in finite elements, engaged in aviation development, specialized in materials. A small half of them were abducted back from the United States by Chen Yunyong. ”

"Those people basically worked in the private sector before, and they themselves had a certain willingness to return to China, and after review, they were allowed to come back."

"By the way, you don't mind that, do you?"

Yang Wei asked with a little worry.

In fact, for him personally, his background and past experience are not too important.

As long as it can pass the review and meet the relevant confidentiality requirements, then he believes that some experience in working outside the country can actually be appropriately relaxed.

After all, they chose to stay there not because they wanted to betray, but simply because they were attracted by better conditions.

This is a very real problem.

It's hard to learn, who doesn't want their skills to sell for a good price?

Money is heroic courage, and when everyone is generally in difficulty, the pursuit of money is not a heinous matter.

What's more, in the treatment of talents, in the past some time, we have not given enough respect, which is a real problem that needs to be reflected.

Now, the above has begun to consciously improve the treatment to attract talents, and it is even more important to show our sincerity regardless of previous suspicions.

This also has the chill of buying horse bones in it.

Of course, he thinks so, not everyone thinks so.

Objectively speaking, there are still many people who are biased, but I just hope that these people do not include Chen Nian.

Hearing his words, Chen Nian smiled and replied:

"Of course I don't mind, as long as I follow the rules."

"But this Mr. Chen is really powerful, Renmei makes a good profit, he can actually turn it back"

"Harm, everyone is still a little idealistic, and it doesn't have to be money worship."

Chen Nian nodded in agreement, these days, there are indeed some experts and scholars who still have ideals.

The domestic economy is not good, and there are many foreign temptations, and they are really supported by their enthusiasm

"How's your preparation going? Is there any progress? ”

"Nope."

Chen Nian replied without a trace of hesitation.

"Do I need to apply for foreign aid? We can talk to the Russian side, they have a similar study. ”

"Not for now, give me a few more days."

"Don't worry, Xiao Nian, the progress of this kind of project is really not measured by days."

Yang Wei said with a smile.

Good guy, I still want to comfort and comfort him, telling him that it doesn't matter if he exports two months late, but what did people say?

Give a few more days.

It's not a conversation on one channel anymore.

The two chatted a few more words, and Chen Nian walked out of the room to relax, and when he came back, his thoughts were much clearer.

He spread out the scratch paper on his desk and re-entered the mood, intending to start from scratch.

According to the take-off mass of the F-35B aircraft, the Stallion Company has adjusted the layout of the whole aircraft for the lift required for take-off, which is the premise of everything.

According to the center of gravity data and the weight data of the airframe, the total lift required for the vertical take-off of the F-35B should be about 18.14 tons, but this part of the thrust is not completely provided by the lift fan, of which the vector nozzle and attitude adjustment nozzle also need to bear 55% of the lift.

In other words, the thrust provided by the lift fan should be around 8.16 tons.

In order to generate this part of the lift, the lift fan not only needs to have a relatively large pressure difference, but also needs to pass a sufficient amount of flow.

Then, the diameter of the lift fan needs to be strictly planned.

This part is the hardest.

Chen Nian frowned and carefully recalled the data he had seen in his previous life, and then referred to the thrust of the conventional thrust fan, combined with the overall body size of the F-35, and finally determined a number:

The diameter of the lift fan is 1.27m.

This is the only reasonable size in the entire airframe layout.

In this way, the inlet mass flow of the fan should be able to reach about 210kg/s.

"Let the 0-0 section be the pressure far field, the inlet is a 1-1 section, and the outlet is a 3-3 section. Lift fan inlet Ds = 1.27m, inlet hub ratio Dh-s = 0.454, liters

The efficiency of the force fan is η=0.87, the total pressure recovery coefficient σe=0.98, q=204kg/s, and the pressure increase ratio is assumed to be π*."

".q(λ) is the dense flow function, from which we can deduce q(λ),Ma1,p1,T1 on the inlet cross-section"

"The lift fan inlet airflow velocity V1 is determined by the continuity equation."

"Compressor efficiency formula available"

"The final lift expression is"

Chen Nian silently recited a series of calculation formulas in his heart, and the movements of his hands became smoother and smoother.

At this moment, his brain entered a state of full capacity, and even fine beads of sweat began to ooze from the door of his brain.

He is like a supercomputer, frantically retrieving knowledge from two planes and two worlds, trying to fuse it together to arrive at the final result.

"So, in order to further accelerate the air, the outlet of the lift fan is a tapered nozzle, and the constraints can be given: Ma3<1, A3

"In addition, considering the ground effect during take-off and landing, there is a lift loss in the lift fan, and the general loss rate should be around 50%"

"The variation of outlet cross-sectional area A3, lift F, and booster ratio π* with λ in the range of velocity factor λ ∈ [0,1] was traversed"

2.165！

The total pressure ratio is 2.165, and the resulting lift can take into account the required lift after the target lift and the ground effect!

Chen Nian threw down the pen excitedly, he subconsciously stood up and walked away from the table, and then approached in disbelief to observe the hard-won result.

This is the first time.

The first time I calculated it, I got a credible result!

And, according to your own calculations, if you take into account the tolerances, it is safe to set the total pressure ratio of the lift fan at 2.2 to 2.4, which can ensure that similar STOVL performance can still be achieved in the case of aerodynamic layout differences between the J-20B and F-35B!

Chen Nian threw down his pen excitedly and couldn't wait to run to Yang Wei's office.

He had to share the news immediately, because the significance of the news was so great

And on the other side of the sea, it was already late at night.

Chen Yunyong sat at his desk, on which was a large pile of scratch paper spread out almost identically to Chen Nian.

And the problem he is trying to solve is the same as Chen Nian, which is to calculate the appropriate total pressure ratio required by the two-stage counter-rotating lift fan.

This is not his first attempt.

It should be said that he has been doing this work for five whole years.

In the past five years, he tried his best to obtain as many resources as possible within his ability, and at the same time, he also turned to many friends in the same industry, but the progress has always been slow.

As Dick told him at the time, his research was too rudimentary.

But why primary?

In the final analysis, the most critical one for start-up is still missing.

But lately, he suddenly felt inspired.

Perhaps, I went in the wrong direction at the beginning.

In particular, it is difficult to get the right results when reasoning from a purely data perspective.

What really works is the physical experiment.

From the perspective of aerodynamic design, how big a fan should be used to reverse the ejection to meet the requirements of the body layout.

As a result, the scope of the data is greatly reduced and the computation is computationally less difficult.

——

It didn't seem like an uncommon idea, and he hadn't thought of it before.

The point is that he didn't have any information about the F-35B in his hands before, only a few words, which were useless.

But now, after finalizing the time to return to China, the special staff passed the information to him, so his research began to advance by leaps and bounds.

It took him less than two weeks to figure out the calculations.

And today, the first result was calculated!

2.21。

Under this differential pressure ratio, the J-20 will be perfectly adapted to the STOVL system, and the theoretical problem of the two-stage counter-rotating lift fan will also be completely solved.

Chen Yunyong's face showed an excited look, and he wanted to shout a few times to vent the emotions stirring in his heart.

But he knew that in his current situation, even celebrating was a luxury.

So, he had to put away all the manuscript papers with trembling hands, fold them in a stack, and then walked step by step in the direction of the bathroom.

Liu Huixia noticed his movements, stepped forward and asked with concern:

"Yun Yong, what's wrong?"

Chen Yunyong lowered his voice and said:

"It's finished."

"Fan? It's done? ”

"That's right!"

He nodded solemnly, a smile on his face that could not be suppressed.

Liu Huixia's expression also became excited, she held Chen Yunyong's hand tightly and didn't say a word for a long time.

The two looked at each other silently, and after a long time, Liu Huixia asked:

"Are you going to burn it?"

"Yes, burn it, it's all in my head, we can't leave a handle on those white ghosts."

"Okay, I'll help!"

As she spoke, Liu Huixia turned around and went to the kitchen to get a lighter, then hesitated for a moment, and then brought the iron pot for cooking into the bathroom.

"Put it in it and burn it one by one, so as not to trigger the smoke alarm."

"I know."

Chen Yunyong lit the first page of the manuscript paper, and the bright yellow flame rose, reflecting the mixed feelings on his face.

"Finally. It's finally progressing a bit. ”

He said with emotion.

"With this first step, when we go back, no matter how bad the conditions are and how weak the foundation is, we can catch up little by little."

"But it might take a long time."

"Time, Huixia, sometimes I really feel that our time is too limited."

"10,000 years is too short, just seize the day."

Hearing his words, Liu Huixia smiled lightly.

She threw a piece of manuscript paper into the pot, and then spoke comfortingly:

"You see, you're still pessimistic in nature."

"In fact, the development of science and technology is leapfrogging, maybe one day, when you don't expect it, the problem can be suddenly solved?"

"Isn't it the same process as when you solve the problem of the fan?"

"No, it's not."

"This problem can be solved, it is still after five years of accumulation. But how many five years do we have? ”

"Your five years, plus other people's five years, will create different results."

Liu Huixia continued.

"Unless, you really don't believe in them at all, you don't believe in that land."

"Not really."

Chen Yunyong shook his head lightly, hesitated for a moment, and then said:

"I'm just regretting that if I hadn't chosen to come out at the time, maybe everything would have been different."

"It's okay."

"On every road, there will be different twists and turns - think in a good direction, maybe in the country, someone has taken your place?"

Speaking of this, a sly smile appeared on Liu Huixia's face.

"Perhaps, the results you are making now have already been made by someone?"

"When the time comes, I really don't know if you should be happy or disappointed."

Chen Yunyong laughed and replied:

"Of course it's a pleasure."

"And, I'll be happy."

His expression became a little fascinated, the flames in the iron pot were still burning, and the faint green smoke gradually drifted away.

The wisp of smoke pierced through the bathroom window and, with the wind, drifted higher and farther into the sky.

Chen Yunyong watched this scene with some fascination.

At this moment, he seemed to be able to see the way home of that wisp of smoke.

(End of chapter)