Back in 1978, I was admitted to Northwestern Polytechnical University.

Chapter 81 Who says we're just daydreaming?
Northwestern Polytechnical University.

“Flutter, that’s not a good problem to solve!” Professor Sha frowned. “At the beginning of World War I, the Handley Page bomber suffered severe vibrations caused by tail flutter, which led to the disintegration of the tail and fuselage. A few years later, the DH-9 also crashed due to tail flutter. After that, engineers began to pay attention to flutter, and even a flutter major was established. Our Northwestern Polytechnical University also has one, but it has always remained at the theoretical level!”

"Hmm, this flutter is a big problem. How about... we ask a sister unit to handle it?"

“That won’t do. Now that we’ve signed a cooperation agreement with Factory 132, the technical issues should be left to us to solve! We’ve been stuck in theory all this time, but now we can finally get some hands-on experience!” Professor Liu said. “I can’t wait! By the way, where’s Liangzi?”

"Recently, Liangzi has been spending a lot of time with the fourth department, tinkering with CNC machine tools..."

Thump, thump, thump! Just then, footsteps sounded outside.

"Liangzi, you're finally back! Factory 132 sent a telegram saying there's been a problem during the trial production and they need you... What are you holding in your hand?"

"The flap actuator cylinders are already usable on the CNC milling machines in the fourth system. We just finished producing a batch of flap actuator cylinders and took them over. Teachers, is anyone tired of staying at the school and wants to visit Factory 132?"

"Flap actuators? Don't they have factories that specialize in making them?"

"No, the workers may be very skilled and produce individual flap actuators that meet the requirements, but the four flap actuators are not consistent, which can easily lead to wing flutter."

Everyone was stunned when they heard the word flutter.

"You're saying their wing flutter isn't due to a design flaw, but rather a manufacturing problem?"

"Yes, how could our design have any problems? We already took flutter into account during the calculations. Based on the results, we strengthened the torsional stiffness of the middle and outer wings and appropriately reduced the wing bending stiffness. Didn't you notice?"

Everyone was a little embarrassed; they really hadn't noticed!
"Liangzi, how did you do that?"

"It's actually quite simple. Among the books I brought back, there's one specifically about flutter. Solving this problem requires a foundation in frequency identification and coupling principles. Our No. 3 computer has this kind of program..."

Professor Liu rushed over to computer number three, tapping away at the keyboard to access the relevant programs and studying them carefully. Professor Sha, meanwhile, found the foreign language document...

"Teachers, who would like to come with me?"

"Let Old Li go!"

Factory 132, conference room.

"Compared to the prototype, the changes are too significant! The wing area has been increased, the wingspan has been enlarged, the outer wing sweep angle has been reduced, and external stores have been added... So many improvements have negatively impacted flutter!"

"That's right, even if you replace the wings with steel plates, it will still vibrate. There's simply no solution!"

Hearing the experts' unanimous opinion, everyone present was on the verge of collapse. In other words, our research and development project was going to fail.

The Air Force is waiting, as are Egypt and Pakistan, especially Pakistan. Qin Liang reiterated that his side wanted to be the main contractor, and now…

"Old Huang, do we really have no solution?" Old Tu looked at Engineer Huang from Shenyang. He was in charge of flutter control on the J-8 project, and even he couldn't solve it, so this was...

"Yes, our J-8 is just a scaled-up version of the J-7. The wings are of great importance, and we dare not modify them at all. Your Factory 132 has no design capabilities. Relying on Northwestern Polytechnical University as a design unit, you want to develop a new fighter jet? That's just wishful thinking..."

"Who says it's wishful thinking?" Just then, a voice came from outside.

Old Tu immediately stood up: "Qin Liang is here! Qin Liang is here! Quickly, please come in!" Engineer Huang frowned: "Even if a recent college student has learned a lot on his own and offered some insights, he can't possibly build an airplane. After all, building an airplane requires years of experience..."

At this moment, Qin Liang stood at the door: "Everyone, we can't solve this problem here. Let's go to the workshop!"

"Hmph, theoretical analysis first, then practical operation. Solving the flutter problem requires a scientific approach. How could such a hothead possibly solve the problem!" Engineer Huang shook his head as he stood up and walked outside. He wanted to see how Qin Liang would embarrass himself.

In the workshop.

"Come on, put on these new flap actuators."

Master Liu's face immediately darkened: "What do you mean? The parts I sewed myself are absolutely fine!"

"Yes, Qin Liang, Master Liu is a level seven worker in the workshop. He makes the parts by hand..."

"Well, the parts were made by Master Liu himself, so there's definitely nothing wrong with them. But... we're trying to find the cause of the problem, and the substitution method is the most common one..."

"Old Liu, let's try Qin Liang's method!" Old Tu said. "We don't doubt your skills, we just want to find the cause of the malfunction."

"Okay." Master Liu nodded: "If it's still not good after you change it, then let's see what you have to say!"

Half a day later, at the flutter laboratory.

"Speed ​​100!" The wings were as steady as a rock.

"Two hundred speed!" The wings still didn't move much!

"Finished? How is this possible? The parts I processed are definitely fine!" Master Liu stared wide-eyed at the wing being tested. He was certain his product was okay, but he didn't know what else could it be if it wasn't his fault!
At that moment, he began to question the meaning of life.

……

"Speed ​​600!"

At this moment, the wings were only trembling slightly, which was completely within the normal range!

"Great, that's wonderful! It really solved the problem!" Old Tu exclaimed excitedly. "Old Huang also said..."

Engineer Huang looked embarrassed, but... he was equally curious: "Is this wing flutter really caused by the flap actuator? Why is that?"

All eyes turned to Qin Liang, who smiled and said, "Well, we're just lucky. After all, Northwestern Polytechnical University doesn't have the technology to develop airplanes. It's just wishful thinking. Besides, building airplanes requires experience. How could a young guy like me, a freshman in college, possibly do that?"

Huang was mortified.

"Liangzi, tell us what happened?" Old Tu asked.

"Well, Mr. Tu, since you asked, I will certainly answer to the best of my knowledge. Actually, this has to do with our entire aircraft industry. For a long time, there has been a lack of standardization. For example, the parts of two identical aircraft cannot be interchanged..."

(End of this chapter)