Li Wenjun and Dong Qingjun live in the same two-person dormitory.
Li Wenjun asked Yang Shouzhuo to make such arrangements. Firstly, he was afraid that he would run around, and secondly, he was also afraid that this bastard would talk nonsense to others.
Dong Qingjun said he was not tired, so he fell asleep on the bed after taking a shower.
Li Wenjun was also a little tired, so he lay down and fell asleep quickly.
In the middle of the night, he was awakened by the strange cry of a nightjar. When he turned over, he saw that the bed next to him was empty.
The bathroom door was open and no one was inside.
Damn it, where has this guy Dong Qingjun gone?
Li Wenjun broke out in cold sweat, jumped up immediately, ran out, and knocked on Yang Shouzhuo's door next door.
Yang Shouzhuo knew this place better than he did, and if anything happened, he would have a witness.
"Huh?! Why are you up at midnight?" Yang Shouzhuo opened the door, his hair as messy as a chicken coop.
"I don't know where that kid went." Li Wenjun raised his wrist, "Looking at the location, he is two hundred meters southeast of me."
Yang Shouzhuo covered his eyes and sighed: "It's probably a hangar. When we were eating just now, he was quietly asking others where the hangar key was, indicating that he would be the first to arrive in the morning and would need the key to open the door."
Li Wenjun and Yang Shouzhuo trotted over and took a look. Sure enough, the hangar door was opened.
The faint blue moonlight shone in from the crack in the hangar door. Dong Qingjun hugged his knees like a statue and sat motionless on the ground.
Li Wenjun and the others went in and took a look. It turned out that he was staring at something as big as a palm in his hand.
Li Wenjun exchanged glances with Yang Shouzhuo, leaned over and asked, "Dong Qingjun, what are you doing? You ran out alone without sleeping. You haven't done enough during the day."
Dong Qingjun stretched out his hand and asked Li Wenjun: "What on earth is this? I thought about it for a long time and couldn't figure it out. I tossed and turned and couldn't sleep."
Li Wenjun said: "Ah, this. Hydraulic sway damper. The shock absorber used in our car is an assembly, which includes hydraulic sway damper and other shock absorbing devices."
Dong Qingjun said: "But this is placed in the blades of the rotor."
Li Wenjun: "Putting this in the blade can increase the damping of the blade oscillation surface and eliminate the instability of the helicopter's ground resonance."
He suddenly realized that this thing was not included in the drawings Uso gave him.
No wonder the helicopter models they make always fly unstable.
Damn it, I'm still dishonest!
Or maybe the drawings submitted to the Ministry of National Defense for filing by the Mili Experimental Design Bureau deliberately deleted some key details to prevent leakage.
What Uso got were the drawings filed by the Ministry of National Defense.
Li Wenjun is not an aircraft expert, but he is learning while doing it, so he only thought about the need for shock-absorbing in the cabin after landing and taking off, but did not think about the need for shock-absorbing in the blades.
Also, looking at it now under the moonlight, the shadows are obvious. It can be seen that this paddle is not actually flat. Looking from the tip of the oar toward the root of the oar, the chord lines of each section of the blade do not overlap. The closer the blade is to the root of the oar, the greater the inclination of the chord lines. Because the twist angle is small, maybe less than 10 degrees, it is not easy to detect with the naked eye under strong light during the day.
This is not marked on the drawings.
He thought about it and suddenly understood.
According to aerodynamics, the blade tip rotation linear speed itself has reached Mach 0.6. When the helicopter is flying level, the forward edge of the rotor will most likely enter the transonic zone, and local supersonic flow is prone to occur, which will generate shock waves. resistance, leading to increased energy consumption and increased risk of bending.
Therefore, the complexity of the aerodynamic environment of the rotor is much more complex than that of the wings of fighter jets and passenger aircraft.
How exactly the chord line inclination of the rotor blade surface is determined requires many experiments and calculations to find the best one.
This is why he built fighter jets and passenger planes first, and then helicopters.
Dong Qingjun was still minding his own business and said: "I know about car shock absorption. But how to design the shock absorption of this blade? Logically speaking, the damper uses dynamic load to eliminate resonance, so the stronger is definitely not better."
Li Wenjun: "Yes, the damper will generate dynamic loads on the propeller hub and blade root, which will have an adverse effect on the fatigue strength and fatigue life of the rotor structure. Therefore, it is necessary to accurately estimate the dynamic load of the damper. This is also important in the strength design of the rotor system. link."
So it is very important to draw pictures while disassembling.
Because I don’t know what else Lao Maozi is hiding.
Li Wenjun said to Yang Shouzhuo: "This drawing requires precise measurement and then drawing."
Yang Shouzhuo said: "Yes."
Li Wenjun said: "Can you give me a copy of the drawings?"
He couldn't remember so many things just by relying on his brain.
Yang Shouzhuo: "I can let you come and see it at any time, but I can't give you the paper drawings because they are military secrets."
Li Wenjun thought for a while: "That's okay."
This thing is inherently a double-edged sword.
If he gets the complete blueprint from Yang Shouzhuo, if the secret is leaked elsewhere, he will start the investigation.
Because he is the only private enterprise involved in this matter.
Li Wenjun and Yang Shouzhuo came out of the hangar and threatened Dong Qingjun with a chorus.
"It is a crime for you to come directly to the military hangar without permission and steal military secrets."
"Fortunately, no damage was caused, otherwise you would have to go to court-martial. The minimum penalty would be imprisonment, and the maximum penalty would be to be shot."
"Don't do this next time, otherwise neither of us can protect you."
"Yes, maybe the entire 'Wenjun Industrial' will be implicated by you. You are still so young, it would be a pity to die in one shot."
Dong Qingjun was frightened for a moment, and promised that he would never dare to do it again next time.
Li Wenjun took him back to sleep.
Yang Shouzhuo locked the hangar.
Fortunately, it didn't alert anyone.
Li Wenjun and Yang Shouzhuo breathed a sigh of relief.
Jiang Qiangjun stood at the door and asked, "You three are up at midnight, what are you doing?"
Yang Shouzhuo's heart skipped a beat: Go ahead, wake up the old man. Trouble.
Li Wenjun said: "Oh, Dong Qingjun said he didn't know what the damper on the rotor looked like. I took him to take a look."
"It's good that young people are eager to learn." Jiang Qiangjun nodded and turned around to go in with his hands behind his back. Suddenly he turned back to Dong Qingjun and said, "You don't even know the dampers on the wings, what are you pretending to be?! Please be quiet from tomorrow on." . The chirping one day made my forehead hurt."
Dong Qingjun had already turned his head and looked elsewhere and didn't listen at all.
Li Wenjun pinched Dong Qingjun from behind.
Dong Qingjun reluctantly bent down and nodded and replied: "I understand."
Wait for Yang Shouzhuo to return to the room.
Li Wenjun closed the door and said to Dong Qingjun with a serious face: "Come on, Qingjun, sit down. I have something important to tell you."
Dong Qingjun waved his hand: "I know, I know. Don't worry, Director Li, I won't run around anymore."
Li Wenjun said: "That's not it. I have to give you an important task. From tomorrow on, you have to draw as many pictures as you can in your notebook. Me too. When we go back, we will look at the drawings and see if there are any missing ones. Whatever you need, try to make up for it.”
Dong Qingjun's eyes were bright: "Actually, I started to memorize it today."
