The Red Era, the Opening University Speech

Chapter 438 Omnidirectional Antennas and Directional Antennas

Until about 4pm.

Li Mucai walked out of the meeting room.

The basic development framework of the Type 04 personal computer was finally finalized.

The goals mainly include three points: the computing speed reaches 5000 million times per second, the type 02 operating system is installed, and color display is supported. Li Mu did not propose too many improvements in other aspects.

After all, with the current level of integrated circuits, it is still very difficult to realize the relatively complete personal computers of future generations.

Therefore, the Type 04 personal computer was destined to be just a "transitional" and "experimental" research project.

He explained all these to Wang Shoujue, Su Dongzhuang, as well as many experts and professors before the project was launched.

However, no one cared at all. Instead, they expressed their understanding.

To be honest, they didn't expect the Model 04 personal computer to be mass-produced.

The speed of computer upgrades in Xiaguo is indeed too fast, and the speed of elimination is far behind the speed of research and development.

This has resulted in some units having just received the latest model 02 computers.

As a result, they were all starting to develop Type 04, and not many units had received the Type 03, so it was nominally eliminated.

This would be a bit of a waste of national resources, so it would be a good thing to just research the technology without considering mass production.

……

Leaves the Semiconductor Research Institute.

Li Mu then went to the Radar Research Institute and found the director Peng Shilu.

When the latter saw him, he warmly welcomed him into the office, made tea for him, and told him about the research results they had achieved in the past period of time.

Since the successful development of the new pulse Doppler radar.

Their experts and professors began to prepare and consider the issue of loading it onto the plane.

But this process is full of difficulties.

Not to mention the backward performance of their fighter jets, there are also many difficulties in their design.

For example, the antenna problem.

The J-6's antenna is a saber antenna, which is mainly used to receive signals and enhance communications.

But this antenna is not compatible with the new pulse Doppler radar.

So they are considering developing new antennas.

While the two were talking, Deputy Director Jiang Nanying rushed over with several key experts and professors from the institute.

Seeing this, Li Mu quickly stood up and greeted him.

"Advisor Li, you don't have to be polite. Let me be frank with you. We came here just to ask for your help." said a professor.

His name is Lin Jiadong, and he is a professor in the Department of Radio Electronics at China Europe International Business University.

Although he is not well-known in later generations, his abilities are absolutely trustworthy, otherwise he would not have been invited by Peng Shilu and Jiang Nanying to participate in the current research.

After he spoke, the other experts and professors also followed suit and begged Li Mu for help.

"You didn't even ask me if I could do it!" Li Mu sighed inwardly.

But he does know the answer to this question.

So he had no way to refuse and could only say:

"I have thought about this before and have some ideas. Now that the experts and professors have spoken, I will just talk about it and we can discuss it together."

"The disadvantage of the saber antenna is that it is prone to ice formation during high-altitude flight and will generate greater starting resistance during high-speed flight."

"In order to overcome these two problems, we can actually consider the research direction of omnidirectional antennas and directional antennas..."

……

Li Mu did not tell the solution right away.

After all, Xia Country’s antenna technology was still relatively backward at that time.

Even if we want to do research, we have to give everyone some "make-up lessons".

However, this little bit of information obviously could not satisfy the people who had become accustomed to him coming up with solutions to problems at any time.

After listening, they first made notes for half a day and asked about some things they didn’t understand.

Then a professor quickly continued:
"Advisor Li, can you give us a specific research direction? Is it better to study directional antennas or omnidirectional antennas?"

His question stunned the experts and professors around him, and they immediately showed strange expressions.

These two types of antennas were invented very early, and their advantages and disadvantages are very obvious.

The directional gain is generally above 9dBi, the signal quality is good and the transmission distance is long, but the design process is complex and the price is expensive.

The omnidirectional structure is simple and the price is cheap, but the gain is very average, only between 2dBi and 7dBi.

From this perspective alone, there is almost no second answer.

Unless, Li Mu has a way to make the omnidirectional gain exceed the directional gain.

"Of course it's a directional antenna. I can't make an omnidirectional antenna achieve the effect of a directional antenna." Li Mu looked at everyone's inquiring eyes and said with a smile.

Whether it is the saber antenna of the J-6 or the flat slot antenna of the J-10, they are both directional antennas, so the answer basically does not need to be considered.

Hearing this, the professor who asked the question realized that he had asked a "stupid question" and looked annoyed.

Looking at the professor's expression, everyone couldn't help but burst into laughter.

After laughing, Li Mu continued to help everyone sort out their thoughts.

The flat slot antenna is actually mainly based on the Babinet principle.

This is an important principle in optics, which permanently describes that the sum of the complex amplitudes produced by two complementary screens at a certain point in the diffraction field is equal to the complex amplitude at that point when the light wave propagates freely.

Using this principle, the radiated field and impedance of an aperture or slot antenna can be related to the field of its complementary antenna.

However, it is still quite difficult to take out the antenna based on just a simple principle.

The most critical issue is processing accuracy, which requires extremely high accuracy in the shape and size of the gap. Its difficulty is not much easier than that of the T/R unit of the active phased array.

Although it can be accomplished with a 3+2-axis CNC milling machine, there are still many problems in mass production.

……

Spent about two hours in the Radar Research Institute.

Only after successfully guiding Jiang Nanying and the experts and professors' thinking back on track did Li Mu get up and leave.

As for the passive phased array radar, he is not in a hurry to take it out.

Eat the meal one bite at a time.

It's not that the strength is impossible, but it starts with a passive phased array radar, which is a bit too difficult.

……

While it's still early.

Li Mu asked Guan Jianmin to drive him to the Aviation Academy.

It took several hours of work.

They finally arrived at the research base hidden in the mountains.

Don't wait for them to get close.

Tang Yanjie, who had received the news long ago, came forward and said with a smile:
"Advisor Li, you're back. The professors you brought with you keep talking about you. It's really annoying me!"

"What's the matter? It sounds like you have a lot of headaches, Dean Tang?" Li Mu asked puzzledly.

Hearing this, Tang Yanjie waved his hand and said:

"It's not a headache. To be honest, I admire them. They are bold and daring. They dared to fly a plane into the sky to conduct experiments after only a few days of arrival."

"She always likes to come to me every now and then to ask about you and when you'll be back."

"But I don't know anything about this matter, so I asked them to wait patiently, but it was useless. They still came here from morning till night."

Although he felt that Huang and the others had too many personnel, he still admired their abilities.

"Experiment, what experiment?" Li Mu was stunned and asked curiously.

Tang Yanjie explained:

"You forgot that you sent a document earlier, which proposed a theory called the Energy Mobility Theory."

“Professor Huang and his colleagues started discussing the issue that day, but everyone had different opinions.”

"So Professor Wang Shicun suggested that we go to the sky to conduct experiments to verify it. After all, practice makes perfect."

After he finished speaking.

Li Mu also reacted.

He didn't expect that in order to verify a theory, Huang Qian and Song Wencong and others would have to go to heaven to try it out.

"It seems like everyone is in high spirits!" Li Mu said with a smile, then walked into the base first.

As they walked, he asked, "Are they still conducting experiments now?"

"That's right, but I heard from Professor Wang that the results of the experiment have been basically confirmed, and the energy mobility theory is indeed useful!" Tang Yanjie followed behind and said.

This result is not unexpected.

After all, as long as a skilled pilot flies once according to the principles of energy maneuverability, he can easily feel the difference.

……

The two of them walked all the way to a two-story experimental building at the Institute of Aeronautics.

But not yet up.

Then he met Huang Qianshi and others who were preparing to come down for dinner.

When they saw Li Mu, their eyes suddenly lit up and they hurried forward and said:
"Advisor Li, you are finally back. Where have you been these past two days? We have a lot of questions that we want to ask you!"

"Yes, the energy mobility theory you proposed is really admirable. It is undoubtedly the most important contribution to the history of fighter jet design in the world!"

"With this theory, the fighter jets we design for the next generation will not only surpass the M-Emperor and Big Brother, but at least be able to fight with them!"

……

Everyone was talking at once.

Listening to the noisy sounds around him, Li Mu suddenly understood Tang Yanjie's pain.

He quickly said:

"I'm sorry, I had other things to deal with, so I was delayed for a day or two. I hope you can forgive me, professors."

"But I came here as soon as I finished my work, just to continue communicating with you."

"I have benefited a lot from communicating with you all during this period. To be honest, I feel sad when I think that you will leave soon."

At the end, Li Mu pretended to sigh deeply.

This is almost a statement.

But there is no way.

There are still many problems to be solved in the development of the J-10 and it cannot be delayed any further.

Upon hearing this, the eyes of professors such as Huang Qianqian, Tu Jida and Song Wencong lit up.

Fearing that he might misunderstand, Huang Qian hurriedly asked tentatively:
"Advisor Li, do you mean... that you plan to invite us to stay for a few more days?"

"Not just a few days, I recently had an idea to research fighter jets, but I regret that my intelligence is limited and I have no way to solve many problems." Li Mu said.

Huang Qianqian and others who heard this immediately said, "We, we can do it!"

They had waited for so long, and this was what they were waiting for. "Advisor Li, as long as you think I'm capable, I'm willing to work with you to develop fighter jets for the rest of my life!" Song Wencong said firmly.

He had wanted to say this for a long time, but he had never found the opportunity.

Seeing this, other professors also spoke up and said:
"In the past, we have always copied fighter jets from other countries, but this time, Consultant Li, you have given us hope for independent research and development!"

"With you here, Consultant Li, we will definitely be able to develop a powerful fighter jet for our Xia country!"

"We have so many experts and professors, and you, Advisor Li. We all have two eyes and one brain. I don't believe we are worse than those foreigners!"

……

Everyone's emotions were very high.

The communication with Li Mu during this period of time has made them see the dawn of hope - the dawn of Xia Country's independent design, research and development, and manufacturing of fighter jets.

In order to make this light brighter, each of them is willing to burn themselves out!
"Thank you all for your trust. I believe that with our joint efforts, we will be able to build the Wulong-1 fighter jet!" Li Mu couldn't help but be infected by the atmosphere and was very excited.

This is what happened here today.

Perhaps it may not be known to people in the past ten, twenty, or even one hundred years.

But one day, the sealed history will be revealed.

The people of the Xia State in later generations will certainly and forever remember that there was a group of people who willingly gave their entire lives for their peaceful life.

……

Led by Huang Qianqian, Tu Jida and Song Wencong, the 12 professors quickly expressed their willingness to join Li Mu's research project team.

They also understand what a rare opportunity this is.

In the past, perhaps each of them had achieved something and produced something.

But those are nothing compared to what we have to do now.

It will surely be recorded in the history of Xia's aerospace development, leaving a strong mark on the past and the future.

But after the excitement.

Someone suddenly came to his senses and asked:
"Advisor Li, did you never intend to let us go from the beginning?"

As soon as this question came up.

Everyone's eyes instantly focused on Li Mu, full of curiosity.

"That's right. Ever since Comrade Song Wencong heard about the professors, I have made up my mind to keep you all. But I was afraid that you might not be willing, so I wanted to wait a while until I am more confident." Li Mu said.

Hearing this, Huang Qian slapped his thigh and said in annoyance:
"Hey, Consultant Li, you should have told us earlier. We've wanted to stay for a long time, but we were afraid you would find it troublesome to have too many people!"

The others, including Tu Jida, Lu Xiaopeng and others, also looked at each other in confusion.

If they had known this, why would they have been so worried? They could have just said it directly and there would have been no need to dwell on it for so long.

"It's okay, it's okay. The result is good anyway." Li Mu couldn't help but laugh and said.

But he didn't think it was a waste of time to delay until now.

After all, it is not an easy task to ensure that all these 12 scientists who come from all over the world and are at the forefront of the fighter jet development field can stay.

……

After finalizing the plan for joint research.

Soon, Huang Qian and others asked Tang Yanjie for help and informed their original units that they wanted to stay in Kyoto for research.

The latter will naturally be happy to see this happen.

He even suggested:

"Why not transfer all the professors' families to Kyoto so that everyone doesn't have to live apart from their loved ones and it will be more convenient for them to go home."

Any important research project will usually take years to complete.

For example, fighter jets will take even longer. It will take at least three years to produce something decent.

It is obviously not realistic to be separated from my family for such a long time.

"If it's possible, that would be great, but I'm afraid I'll have to trouble Dean Tang to take care of it." Huang Qian and others had the same idea, so they did not refuse.

Even if their family came to Kyoto, they might not be able to see each other many times throughout the year.

But it's always better to be closer.

……

After consulting a group of professors.

Tang Yanjie left quickly and excitedly, looking like he was going to fight a tough battle.

But it’s almost a tough battle.

After all, it would take some effort to snatch people from many units, even if he is the dean of the Aviation Academy.

On this side, Li Mu, who stayed behind, continued to discuss the development plan of the Weilong-1 fighter with Huang Qian and others.

But it’s still too early to talk about plans.

Li Mu said:
"The current technical conditions and industrial foundation cannot actually meet our research and development requirements, so we must first overcome some process problems."

"For example, our domestic gantry milling machine technology is still imported technology and is seriously backward."

"In order to make up for these technical deficiencies, we need to achieve many breakthroughs to lay a solid foundation for the birth of fighter jets."

Although Huang and 12 other people have joined, the development team of the Wulong-1 fighter jet is still a little short of staff at present.

Because they have so many problems to solve!
Gantry milling machines are only a part of aviation machine tools; there are also CNC gantry milling machines and heavy-duty horizontal lathes.

But even if they solve this, there are still more problems waiting for them.

Flexible tooling technology, shot peening technology, vacuum melting technology, investment casting process...

Each technical process is a difficult problem that countless scientific researchers have spent half their lives trying to overcome.

"Advisor Li, I know a professor who has profound attainments in gantry milling machines. If you think it's possible, I'll write a letter and ask him to come over." Huang Qian said immediately.

As soon as he opened his mouth, other professors also offered to send people to help.

Of course Li Mu would not refuse. He wrote down the people they recommended one by one and asked Tang Yanjie to invite them later.

Followed by.

He also talked about the problem of the Weilong-1 engine.

In this regard, everyone knew that Li Mu planned to research turbofan engines, but they still had some doubts about this technology.

After all, in the 60s, turbojet engines were more common due to technical limitations and cost considerations.

Although the turbofan engine combines the characteristics of a turbojet engine and a propeller engine, it has higher fuel efficiency, lower noise and better economy.

But these still pale in comparison to turbojet engines, which have a simpler structure and lower maintenance costs.

Since it is a discussion, everyone expressed their opinions and said:
"At present, turbofan engines are still more suitable for civil passenger aircraft, unless we can achieve new technological breakthroughs."

"That's right. The structure of the turbofan is more complicated and has more auxiliary equipment. Judging from the current situation, it is better to choose the turbojet with powerful output power."

"Advisor Li, please stop hiding it. Just tell us what you have to say. We will learn from you."

……

As they talked, everyone's eyes gradually turned to Li Mu, waiting for his answer with great anticipation.

Turbofans were not as good as turbojets, that was in the past.

But now that they have Li Mu, they may be able to build a better turbofan engine.

"In fact, there is a method, but it is also quite difficult to implement," Li Mu nodded slightly and said.

Huang Qianqian smiled and said, "Don't tell us the difficulty first, tell us what the method is!"

"Wait, Professor Huang, Consultant Li, let me find a notebook first." Song Wencong interrupted hurriedly.

The other professors didn't say it.

But his hand had already honestly reached for the paper and pen at hand.

After everyone is ready.

Li Mucai continued:

"We can start from four aspects: materials, cooling systems, control systems and propulsion technology."

"Let's talk about materials first. In order to make turbine blades work at higher temperatures, we can consider developing high-temperature alloys and ceramic-based composite materials..."

"Speaking of the cooling system, the current turbofan engine mainly uses single-channel internal cooling, which uses airflow to cool the turbine blades by setting a channel inside..."

……

The next 5 days.

Li Mu basically spent all his time in the conference room. Apart from eating and sleeping, he would discuss issues related to aircraft engines with Huang Qian and others.

Some principles are easy to explain, but very difficult to put into practice.

Without repeated discussions and verification, it would be difficult for him to conduct research with confidence even if he had the information himself.

After all, the industrial bases are different, and some methods may be feasible in the future, but may not be feasible now.

……

Walk out of the conference room.

Li Mu stretched, said something to Huang Qian and others, and prepared to leave the Aviation Academy.

He walked for many days.

It is not clear whether there are any problems with the development of the Xuanwu main battle tank. It is time to take a look.

Of course, before leaving, he had to rest for a day as usual.

Otherwise, even if he went to the Automotive Research Institute, they would stop him at the gate.

Just as Li Mu was walking downstairs, thinking about how to reasonably avoid the holiday.

Suddenly, Tang Yanjie came over and said with a smile, "Advisor Li, I have news for you. Dean Guo asked you to go to him first after you leave."

"No problem, I'll go there as soon as I get back." Li Mu said immediately.

This is news that even Tang Yanjie didn't know with his identity, so it is most likely related to the development of the Xuanwu-1 main battle tank.

It couldn't be something as trivial as asking him to visit a film studio.

……

After saying goodbye to Tang Yanjie.

Li Mu went to the Chinese Academy of Sciences without stopping.

After entering the door, I went straight to Guo Mo's office.

As soon as I got closer, I heard a hearty laugh coming from inside.

Hear this laughter.

He knew it wasn't a bad thing.

"President Guo, what good news is this that makes you so happy?" He said with a smile as he walked in.

Hearing this, Guo Mo, who was talking to someone, immediately stood up from his seat and said, "Come on, let me introduce you to someone. This is Consultant Li Mu!"

Follow the direction of his hand.

A middle-aged man in his 40s wearing glasses who was sitting on the sofa stood up and said, "Hello, Consultant Li, I'm Hu Xuhua!"

"Hello, nice to meet you." Li Mu smiled and shook hands with the other party, while quickly searching for the other party's name in his mind.

(End of this chapter)