Siheyuan: I eat melons while doing scientific research

Chapter 1206 25? 76 is fine! (5k)

After all, steel core wind capped armor-piercing projectiles are much cheaper than tungsten core discarding sabot armor-piercing projectiles, and are sufficient for routine training and even actual combat for the time being. Moreover, as an air defense weapon, we must also consider the possibility of going abroad for combat or even foreign aid.

Gao Zhendong did not object. Monkey version ammunition was still needed, and steel core bullets could indeed meet the current performance requirements. It was not a bad thing to save a little.

Even if the tank is being cleaned, given the fragile armor of the West, it is hard to say whether the sides and rear can withstand steel-core bullets.

"Hey, Chief Engineer Gao, now that we have developed this armor-piercing discarding sabot projectile, it can also provide support to the infantry fighting vehicles." Professor Liu became even more excited when he thought of this.

After all, anti-aircraft guns are not doing their job properly, but infantry fighting vehicles are doing their job properly.

Hans 88 Anti-All Cannons: You say that again?!
Gao Zhendong was ready to turn around and leave when he was stopped by Professor Liu. "Professor Gao, I remember you said that if you put a radio proximity fuse into a 25mm gun, the fuse would take up more than half of the gun, right?"

Gao Zhendong nodded. "Yes, that thing not only needs circuit components, but also antennas. Considering power and other issues, the current components cannot be made too small, so it is not very convenient to put them into the 25mm cannon. The size of a 25mm warhead can only accommodate a proximity fuze, and it has to be a very special kind."

Not to mention now, even decades later, installing proximity bombs in 25mm guns would still be a cost-effective undertaking.

Professor Liu was happy: "No need for 25mm cannons, no need for 25mm cannons. It's like this. We have comrades working on radio proximity fuzes, but the effect... Let's put it this way, let alone 25mm cannons, even 76mm cannons can't be installed. Not to mention the reliability and anti-interference issues."

25mm cannon? Professor Gao's requirements are really high. Forget 25mm cannon. If you can fit in 57mm cannon, all the comrades will call you uncle...

No, you can't say that. Professor Gao has done so many unexpected things. It's easy to get into trouble if you say that. The main thing is that you can't represent other comrades casually.

Gao Zhendong was stunned. To be honest, he really didn't think much about this thing. He subconsciously thought that this thing was fine.

In fact, our radio proximity fuses were a bit unreliable until the 80s, so we even bought a production line abroad.

"Uh... let me think... let's put it this way, 57mm cannon, 57mm cannon is no problem. If it's smaller, we have to think of other ways." Gao Zhendong estimated for a long time and felt that this thing should not be difficult.

The main reason was that when he was doing research with his mentor in his previous life, he had done research on Doppler distance measurement and speed measurement, so he was quite familiar with this aspect, especially the current mainstream small-caliber radio proximity fuze, which is commonly used. In this life, he has strengthened his knowledge of Doppler radar, so he is more confident.

"Really? That's great! Professor Gao, please stay in the office today. I will ask the comrades who are in charge of radio explosives to come and find you right away!" Professor Liu instructed Gao Zhendong and ran away happily.

Gao Zhendong went to his own office first, while Professor Liu went to inform relevant comrades of the good news.

While Professor Gao is here, we should quickly sort out the problem. If we miss this opportunity, we will have to wait until next week.

Being able to catch Professor Gao fishing with a hand-cranked Gatling gun was a pleasant surprise.

Looking at Professor Liu's hurried back, Gao Zhendong shook his head, turned around and went to his office to wait.

If there really was a problem with the radio proximity fuse, he really had to help fix it right away, for a simple reason.

——In any case, some anti-aircraft artillery units will enter Jiaozhi. Even if our missile units also provide support, anti-aircraft artillery is currently an important means of supplementing air defense.

The lack of a reliable radio proximity fuse had a huge impact on the anti-aircraft artillery unit. It would be fine if they could not hit the enemy planes, but for Gao Zhendong, it was not his side that was bombed. But when he thought about the possibility of causing greater casualties to the anti-aircraft artillery unit, Gao Zhendong could not stand it!
In a laboratory of Beijing University of Technology, a comrade and his students were looking at a row of fuses in front of them with sad faces.

The actuation stage of these fuzes does not have a detonator, but is connected to a detection device to detect the output of its actuation signal.

"Turn on the interference source..." Following the comrade's instructions, a classmate pressed the switch.

Soon, on the computer screen, four of the ten color blocks representing the detonation of the fuse turned white.

"No, according to this plan, with just this little interference, there will be a 40% false operation rate. If we encounter high-power sweep frequency interference, won't everything explode?" The comrade cursed, the students were silent, the teacher was very angry, and the consequences... the consequences were not serious, at least for them as students.

"To put it bluntly, as long as the fuses are connected to electricity, you can just start an electric motor next to them and they will explode!" This comrade was still talking crazily, but he was scolding himself anyway, so it didn't matter.

He was the one who made these fuses.

At this moment, a voice came: "Xiao Le! Xiao Le! The fuse is not fixed yet?"

"Teacher Liu, you guessed it right. If the sensitivity is increased, the reliability will be poor. If the reliability is good, it will not explode at all." "Xiao Le" was much more respectful to the old professor. At least he restrained his temper. Hearing the title, he guessed that this person had taught him in the past.

"Don't be discouraged, I have good news for you!" Professor Liu said with a smile.

"Good news? What good news?"

"It's like this..." Professor Liu leaned over and whispered to "Xiao Le". As he spoke, "Xiao Le's" expression slowly changed and gradually relaxed.

"Really? Hey! Look at my stupid brain. I forgot to ask for advice from such a great master in the academy!"

"The main reason is that you don't know that he is familiar with radio frequency. Not to mention you, I just found out about it from what he said just now." Although everyone often has meetings together, different meetings have different professional directions, so most comrades are in a state of groping in the dark about Gao Zhendong's abilities. They know, but not everything.

"Thank you, Teacher Liu. I'll go find him right away! You guys, stop the experiment first, study hard and wait for me to come back!" The comrade who was working on the radio proximity fuze quickly packed up his things, turned around and rushed towards Gao Zhendong. In fact, they were not far away.

As for the experiment, it is of no use at the moment, so it is better to stop it and let the students consolidate their basic knowledge.

On this side, Gao Zhendong had just sat down in his office when a comrade in his 30s came over.

"Hello, Professor Gao. I didn't expect you had such good stuff hidden here." As soon as the visitor opened his mouth, it was clear that he was no stranger to Gao Zhendong.

This is normal. Although radio proximity fuses are more related to radio frequency, they are both related to electricity after all. The college that Gao Zhendong is in at Beijing University of Technology is the same college as this comrade.

Gao Zhendong took a look and realized it was an acquaintance: "Hey, Professor Le, I didn't know about this either. Look at what has happened."

Professor Le is actually an associate professor and is young and energetic.

"Then I don't care. I'll blame you for this matter, hahaha." Professor Le is also relatively young, so he speaks in a casual manner and is not at all shy.

Gao Zhendong said: "It's not that I blame you, but you have to tell me what's going on in detail first." It's impossible to make a judgment without understanding the situation, and Gao Zhendong is not a god.

"Yes, yes, yes, please listen to me first. The radio proximity fuze we developed is the most traditional continuous wave Doppler fuze..."

The continuous wave Doppler radio proximity fuze is considered the earliest radio proximity fuze. It is used in all missiles, including the famous "V-1" missile.

Although this thing is traditional, it is the most suitable for use in artillery shells because it has the simplest structure, the smallest size, and the cheapest price. In the simplest case, it only requires three transistors and a small number of peripheral circuits. Mass-produced common goods like artillery shells are the first choice before technology and economic development reach certain conditions.

As Professor Le was talking, he took out a notebook and flipped through it, showing it to Gao Zhendong.

Comrade Lao Le is still very pragmatic, or it cannot be said that he is not pragmatic. He has a limited understanding of the principles and methods of radio proximity fuzes and there are not many options to choose from, not to mention that this principle is the most suitable for anti-aircraft guns.

After listening to what he said, Gao Zhendong picked up his circuit schematic and looked at it carefully, while Professor Le was waiting on the side. Even the most talented programmers would be confused when they first received someone else's program.

Gao Zhendong looked at it and asked, "What is the most important issue now?"

"I don't know what the problem is, I only know the symptoms..." Professor Le has very clear ideas and knows that symptoms and problems are not equal.

"Then tell me about the symptoms." Gao Zhendong asked while looking at the patient.

Many comrades knew that he had this ability. Those who had been in Classroom 61 had seen it many times and it had been spread out long ago. Professor Le did not think that he was absent-minded.

"There are two main symptoms: large size and poor anti-interference! As for the others, we haven't reached that stage yet and cannot find them yet."

It’s true that Comrade Lao Le’s thinking is very rigorous. It’s not that it can’t be discovered, but that it doesn’t exist.

Wow, the two most fatal symptoms come up right at the beginning. One determines whether it can be used, and the other determines whether it is easy to use. Both are the most basic ones. No wonder Professor Liu couldn't help but ask about it for Gao Zhendong when he heard him casually mention the radio proximity fuse.

At this time, Gao Zhendong had almost understood the circuit. The circuit of the continuous wave Doppler proximity fuze was not very complicated.

"Your circuit is a very classic continuous wave Doppler proximity circuit." Gao Zhendong sighed after reading it.

"Hey, I don't have any other skills, but it's not a problem for me to ask myself questions rigorously and seriously." Professor Le said with a smile.

Huh? I'm not praising you.

"Uh... well... the first problem with your circuit is that it's too classic." Gao Zhendong pondered, not knowing whether being so straightforward would hurt Professor Le's feelings.

But he was worrying too much. Professor Le was very strong inside: "Ah? I was still feeling so smug. After all this time, the first problem arises here." He could make fun of himself, so it seemed that everything was fine.

Gao Zhendong nodded and smiled, "Yes, your circuit is very complete, and the functional division is very clear. The RF oscillator, mixer, detector, amplifier, and execution stage are very clear from front to back, step by step..."

It sounds like a compliment, but Professor Le, having learned from previous experiences, always feels that something is wrong.

As expected, Gao Zhendong changed the subject: "But the problem is that it is too clear. There is no need to separate them so clearly. The three levels of RF oscillator, mixer, and detector can actually be completed by using a transistor with appropriate peripheral circuits to form a self-heterodyne transceiver. This can save two transistors and some peripheral circuits, and the volume can be reduced."

Professor Le's fuse was implemented in strict accordance with the principle block diagram of continuous wave Doppler, but he did not take into account that some circuits could be shared.

Although the size of transistors is getting smaller with the development of domestic semiconductors, the difference between 3 and 5 transistors, as well as the peripheral circuits, is still quite large.

Professor Le is so exhausted, yet he can still do this.

Gao Zhendong said as he picked up a piece of paper: "Come on, let me draw one for you. It's quite simple."

After saying that, Gao Zhendong directly drew a circuit schematic of a continuous wave Doppler fuze. After finishing it, he also explained it in detail to Professor Le.

What Gao Zhendong meant this time as "simple" was really simple. After all, if this thing was complicated, it would not be used here. Professor Le understood it almost immediately after seeing and hearing it. In fact, even if Gao Zhendong didn't explain the diagram, he could figure it out by himself after spending a little time.

"... As for the specific parameters of the components, I won't go into details. I can't tell you now. It is related to the specific technical and tactical indicators you choose. You need to determine them yourself in practice."

Professor Le said, "No, no, the food is already in my mouth, and I need you to help me swallow it. That's too unreasonable, hahaha." At this point, he couldn't help laughing, and he laughed very happily. Just this one suggestion could reduce the size of his fuse by almost 1/3.

57mm is promising!
Don’t get excited, don’t get excited. There are other symptoms. It will be useless if these are not resolved.

Not only him, Gao Zhendong also understood this truth: "As for your poor anti-interference ability, can you first tell me about your general performance and what anti-interference measures you used?"

It is impossible that Professor Le did not take any anti-interference measures at all, it’s just that the measures he took may not be satisfactory, so Gao Zhendong first needs to figure out what he has done.

"The first manifestation is that the detonation distance of the fuse is widely dispersed. Even if it is a reliable action, the detonation distance around the target is quite uneven..."

Before he finished speaking, Gao Zhendong waved his hand and said, "This is not a problem of anti-interference. This is a natural defect of this type of fuze. Some of it can be eliminated by strictly ensuring the consistency of components, proper design and process control, but some of it is caused by the principle. In different directions of the target, due to the intensity of the echo, the dispersion of the explosion distance of this fuze is large. There is no cure. But as long as the parameters are designed properly, this dispersion is not a big problem."

The dispersion is large, right? Then I just need to shorten the upper limit of the detonation distance and make the explosion range exceed the dispersion.

Although they are all scattered, they are composed of two parts. One part can be controlled, and the other part is basically uncontrollable considering the environmental limitations and cost requirements of this fuse.

Gao Zhendong explained it in detail to Professor Le, who was stunned and felt as if all his work over the years had been in vain.

The bad news: there's no hope.

The good news: There are other ways to make up for it.

"The other problem is that the anti-interference is really poor. This is our experimental record, please take a look..." Professor Le felt relieved, at least one part of it was solved first.

Gao Zhendong took a look and laughed: "Well, it's a little bit worse..."

Facts are facts. The probability of this fuse malfunctioning under interference is ridiculously high, and the interference is not very strong.

Professor Le felt a little embarrassed, but he understood that one should stand at attention when being beaten. If something was not done well, it was not done well. The reason was another matter.

So now his idea is very simple, to expose all the problems to facilitate Professor Gao's analysis: "We used some anti-interference methods, such as increasing the transmission power, reducing the receiving sensitivity, making the antenna as sharp as possible, compressing the receiver's passband, increasing the dispersion of the fuze operating frequency, and connecting the power over a long distance. We used all these methods that can be used."

When Gao Zhendong heard about long-distance power connection, he was stunned for a moment and asked a question specifically. Then he found out that it was roughly the same as the delayed start circuit he used in college, delaying the full or partial conduction of the circuit.

After listening to it, Gao Zhendong said: "Well, it's a very classic and theoretical anti-interference method, which is directly deduced from the working principle formula."

If it had happened before, Professor Le would definitely think that Gao Zhendong was praising him, but after Gao Zhendong drifted and turned around several times before, Professor Le felt that these words were probably not good words, or not entirely good words.

Professor Le continued to explain the situation: "But some of these methods are limited by environmental conditions, such as power. This thing not only needs to increase the power of the tube to make it larger, but the key is to increase the power supply to ensure power supply. After careful calculation, the increase is not much. Some will affect the performance of the fuse, such as reducing the sensitivity. If it is reduced too much, the thing will not explode directly, or the effective distance will be like a collision fuse. As for the others, they all have problems of one kind or another. Some of them, I don't even know if they have any problems or whether they work."

With limited measurement and monitoring methods today, many things cannot be analyzed quantitatively, and even qualitative analysis is not very reliable.

Gao Zhendong nodded: "I understand, let me think about it..."

"Well, this matter is rather troublesome. Professor Gao, please take your time to think about it. I am not in a hurry."

Gao Zhendong shook his head when he heard this: "I'm not thinking about that. I'm thinking about which one or which ones are more suitable for you..."

Professor Le: ???!!!!
(End of this chapter)