During the Goryeo War, the maximum speed of the main reconnaissance aircraft of the United States, the P-51 "Mustang", was 708 kilometers per hour, the maximum speed of the main fighter F-86 "Sabre" was 960 kilometers per hour, and the maximum speed of the most advanced bomber B-29 "Super Flying Fortress" was 574 kilometers per hour.

As we all know, the speed of light is 299792 kilometers per second.

Therefore, theoretically speaking, as long as the air defense personnel are well-trained, pay full attention when carrying out their tasks, and wave their flags in a timely manner after discovering the target, the "early warning" effect of this air defense system can be achieved as long as the news of the "attack by enemy planes" is transmitted from station to station.

The principle is also very easy to understand, and even a rough person like Uncle Luo who obviously has no culture, also introduces it with relish and pride.

But Zhang Zengshu couldn't laugh, his mouth opened, wanting to explain something, but he still didn't say it after all.

The library of Jinling University has a rich collection of books, and in the four years of college, Zhang Zengshu went to the library to read a lot of books in addition to indulging in games, including several books about the Goryeo War.

Several of them mention these "air defense officers", but they are very small, and most of them are only a few paragraphs, not a single page. Such a large amount of content is enough to show that this seemingly reliable "air defense system" did not play a big role in the entire war.

In fact, if you analyze it carefully, it is not difficult for Zhang Zengshu to analyze the reasons.

This was because at that time China did not have air defense radars, a sufficient air force, a sufficient number of air defense weapons, and even a regular air defense force...... There is no way out.

This method has great limitations, for example, if the weather is not clear enough, and if it is cloudy, the reconnaissance planes of the United States are high above the clouds, and when they are deep enough to penetrate the border of China, they will be lowered to carry out reconnaissance tasks, and then it will be too late for the "air defense personnel" to discover them.

Moreover, it is still the early stage of the war, the Chinese volunteers have not yet crossed the Yalu River, the two countries have not officially started the war, the vigilance of the United States side on this side is not high, and the force invested is not large, even if the transport convoy is discovered, taking into account the international influence, it is unlikely to attack directly.

But when the war officially began, it was different, and the US Air Force at that time used "saturation bombing tactics".

To put it simply, they divided the map of the entire Goryeo Peninsula into fixed areas, and these areas were assigned to bomber groups to be responsible for day and night, regardless of financial and material resources, working in shifts, ensuring that at all times, each area has its own fighter patrols to ensure air supremacy, and then thousands of bombers take turns to carry out non-stop bombing of any area that is not controlled by themselves, whether it is a big road or a small road, as long as it seems to be a road that can be walked. Blow them all up.

In such a situation, even if those conscientious "air defense officers" discovered the plane of the Mi people and issued an early warning in time, what is the point?

This is a pure, stupid way to oppress people, but stupid is stupid, and it is not so easy to solve it, even for Zhang Zengshu, who has received a modern complete knowledge system education, he can't think of any way to counter this stupid tactic under the circumstances at that time.

So, he could only choose not to say a word.

……

The big truck is still swaying forward, and Zhang Zengshu is still learning to look around on the roof of the car with a bearded uncle.

To be honest, this process is very boring, there are either mountains or trees on all sides, the sky is as blue as a wash, the flags of the air defense officers have not been waved once, and the bearded uncle next to him is also a stuffy gourd who doesn't like to talk much...... All of this is making Zhang Zengshu's novelty and excitement at the beginning slowly fade.

Accustomed to the modern fast-paced society, he usually has to take out his mobile phone to swipe a few news when he goes to the toilet, and suddenly encounters such a slow-paced game, Zhang Zengshu can't help but be a little bored, so he has to continue to think and analyze:

With such a slow pace, the time in the game can't be 1 to 1, right? The Goryeo War lasted almost three years, so wouldn't this game have to be played for three years? It can't be so exaggerated, right?

Oh, the holographic panel can be summoned, the [exit game] button can also be clicked, and the bearded uncle next to him doesn't show anything, it seems that the NPCs in the game will automatically ignore the player's strange behavior......

But it's not a matter of waiting, why don't you quit? But if you quit, what will happen next time you enter the game? Continuing the role? When I quit, did this character still exist in the game? If there are other players, this should be an online game, so it is very strange to suddenly have one less person, such as cooperating with other players, carrying a box of heavy cannonballs, one person suddenly goes offline and disappears, and the other person is going to be smashed in the foot? And when there is a war, a person suddenly disappears and suddenly appears again, which is also too abrupt......

Well, if you analyze it this way, after I go offline, the role of this "Gua Wazi" should still be in the game, and I just became his controller after I went online!

Right! That's how it should be!

However, I don't know if I can change my role, if I have been in logistics, it will be difficult to make meritorious contributions, and my marksmanship is also ...... Wrong! It should be possible to change roles!

It's war! The continuous bombing of the United States people, although there are many soldiers who died on the front line, there are also many martyrs who fell on the logistics support line! I remember what the book says...... Right! In the first year after the start of the war, Hwakook lost two-thirds of its transport vehicles on the battlefield of Goryeo! I'm probably going to die as a transporter!

If the character dies, the next login will definitely not be this character, and it must be replaced by another one, otherwise it will be impossible not to let me play, right?

……

In the infinite emanation of Zhang Zengshu's thoughts, time flowed slowly.

The sky gradually darkened, from white to blue, from green to yellow, and then the sunset filled the sky.

Summoning the holographic panel and looking at the time, Zhang Zengshu found that more than four hours had passed since he entered the game.

It seems that our convoy left in the afternoon...... I don't know when I'll be able to get to the front line......

Oh, by the way, what day is it today? It seems that our volunteers crossed the river...... Right! It's October 19th! Then on October 25th, I fought with the devils of the United States for the first time!

Thinking of this, Zhang Zengshu turned his head and was about to ask Luo Beard about the date.

However, before he could open his mouth, the beard spoke first: "Gua Wazi, this is about to get dark, but it's not yet time for us to relax and rest, we also have a task at night!" ”

As he spoke, he untied a small cloth bag trapped around his waist and rummaged through it.

Zhang Zengshu didn't understand, he could understand this air defense officer who had to observe the air defense during the day, but what could he do at night? Could it be that those air defense officers will still turn on the lights at night to send signals to everyone? At night, the lights are dark, even if you want to find the plane of the United States, it is not easy......

What came out of his beard was a small bell that looked like it was made of brass, and a metal rod that was also made of brass.

Then he explained: "You also know that the plane of the devil of the United States flies day and night, and there are many people who come to investigate at night. At night, our team can't turn on the lights! ”

"If you don't have your headlights, how do you see the road?" Zhang Zengshu pointed to both sides of the road, expressing puzzlement.

The convoy is driving on the small road, the road is not wide, two trucks side by side may not be able to drive, not to mention the potholes, the roadbed is also very high, if you accidentally fork, the whole car will have to overturn in the ditch.

"Listen to me!" The beard looked serious: "You have to listen carefully, you must not hear it wrong!" ”

Zhang Zengshu closed his mouth and listened.

"At night, it will all depend on the efforts of the driver below, with the help of the moonlight and the reminder of the vehicle in front of you, to drive blindly in the night!" The beard explained carefully: "Wait for the whole team, only the No. 1 car at the front is allowed to turn on the lights from time to time, and the Wang squad leader on their car is also the best driver in our company, and he is the leader of the team!" ”

"When the time comes, the observer on the No. 1 car will ring this bell and give directions to the cars behind, and we will pass on the instructions one by one, you remember, turn left and knock once, turn right and knock twice, do you know which side is left and which side is right? I'll tell you a good way to remember, the hand you use to eat is the right ......."

"Wait!" Zhang Zengshu couldn't help but interrupt him: "I know left and right, but this bell doesn't seem right, right?" This doesn't make sense, that...... In this way, the driver behind can only know which way to turn, but he doesn't know exactly when to turn and how big a turn it is......"

"Hey, didn't I say it earlier, it's all up to the driver's work below!" The beard explained: "We are here to make a reminder!" Remind them to pay attention to the following, and ...... What else...... Oh, yes! And don't drive too fast and hit the car in front of you! Our task is very important! This is even the summary of the meeting inside, this ...... The wisdom of the people! If you don't understand, don't talk nonsense! ”

Looking at the serious expression on his bearded face, Zhang Zengshu hesitated for a long time, but swallowed the words that were about to come to his mouth.

Forget it, if you say it's useful, it's useful, it's a big deal to overturn.

……

Night finally fell, the stars were shining, and the moon was like a hook.

The speed of the car slowed down, and the sound of bells being rung one after another on the big trucks continued all the way.

Looking at the beard next to him, listening carefully, and ringing the bell seriously, Zhang Zengshu suddenly felt a little emotional.

I wonder if more than 70 years ago in reality, was there really such a group of enthusiastic young people, sitting on the roof of this rickety truck, using such primitive bells and sticks to measure the distance of sound?