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

Chapter 5: On my very first day here, I already have to do work?
Professor Sha was also stunned: "You haven't gone to university yet? What you just said..."

"Oh, my neighbor used to live next door. A few years ago, an old professor who came to the countryside stayed there. He brought a lot of books with him..."

"Really? What's his name?"

Professor Sha was very excited; perhaps he even knew them!
“I asked him a few times, but he wouldn’t tell me…” Qin Liang didn’t dare to make up a name, in case it didn’t match up with the person in question, then something bad would happen: “Many people in the village call him Stinky… Old Ninth, so I call him Uncle Ninth.”

"Sigh, those were chaotic times. But you're a good kid; you didn't let your studies suffer," Professor Sha said. "What you just mentioned are all flaws in the J-7. But how exactly should they be fixed?"

"Professor Sha, I do have some ideas, and I'd like to boldly bring them up now, hoping you can give me some guidance."

Now that we've come to this era, we must promote the development of our nation's aviation industry! The 1970s and 80s presented the best opportunity to engage with the West, and we must seize it and develop it rapidly!
Therefore, Qin Liang didn't hold back and began to introduce the improvement ideas from later generations.

“We need to make minor modifications that can have a significant effect. I think we can keep the inner part of the wing unchanged and reduce the sweep angle of the outer part, for example, from the original 57 degrees to 42 degrees, and simultaneously sweep the trailing edge forward. The biggest advantage of doing this is that it can increase the wing area and expand the wingspan, thereby reducing the wing loading!”

The larger the wingspan, the greater the aircraft's maneuverability, but it will reduce high-altitude and high-speed performance; it's a matter of choice.

"Won't doing this reduce the high-altitude, high-speed performance?"

"Actually, the MiG-21 has very good high-altitude and high-speed performance. If it weren't for the limitation caused by the elastic deformation of the fuselage which reduces directional stability, it could even fly up to Mach 2.3. With our modifications, we should still be able to guarantee that it can fly up to Mach 2."

Qin Liang spoke as if he were a designer at the Mikoyan Design Bureau. However, Professor Sha nodded repeatedly. He had heard Old Tu mention something similar at Factory 132, and it was indeed true!

Only the outer half of the wing was modified, while the interior remained unchanged. This was, of course, to reduce costs, since if too much money was spent, the project wouldn't be approved!

"Of course, simply increasing the wingspan isn't enough; we also need to add leading-edge maneuvering flaps to the wings to improve the lift coefficient during takeoff and landing..."

The performance of the wing is directly related to the performance of the aircraft, and designers put the most effort into it. The leading edge flap is what you can see when the front of the wing bends downward during the takeoff and landing phase. This can reduce airflow separation at the leading edge of the wing and improve the maximum lift coefficient and critical angle of attack.

In the West, this is already a widely used technology, but in the East, airplanes do not yet have it!

"Add flaps?"

"That's right. When the Russians were developing the MiG-21, they used delta wings for the first time. They also had the idea of ​​adding flaps, but it was not mature enough in the early stages and was not installed on the aircraft. Now it's almost the 1980s, and we should also make use of this technology that the West has long mastered."

"Hmm, what you're saying..." Professor Sha pulled out a Hero brand fountain pen from his pocket, then looked around for paper, his gaze landing on the briefcase that Niu Guishan was carrying.

Helpless, Niu Guishan took out a stack of manuscript paper: "This is all I have... Hey, don't take it all, leave some for me!"

Niu Guishan watched helplessly as Professor Sha monopolized all his manuscript paper, then began to perform calculations on it with lightning speed...

Okay, here you go!

"Come on, Qin Liang, let's eat." Niu Guishan gestured.

"Thank you, Teacher Niu."

Snapped!
Professor Sha had already brought over a dozen sheets of paper: "Come on, Qin Liang, let's calculate it by hand together and try to finish it before dark today. I'll have the school's carpenters make it tonight, and then we'll go to the wind tunnel..."

Calculate by hand? I'm not good at that. In the future, I'll prefer typing away on a keyboard. Isn't a computer much better?

Seemingly sensing Qin Liang's predicament, Professor Sha magically produced two special rulers from his pocket.

The ruler is exceptionally wide, about three or four times the width of a typical student ruler. It's made of aluminum alloy and covered with densely packed graduations. The central section can be pulled out, and it's encased in an outer layer of acrylic oil level. This… is a slide rule!

Before the advent of electronic calculators, almost every researcher had one, just like the abacus in ancient times. This thing was equivalent to an analog computer!

Addition, subtraction, multiplication, and division are just routine operations for it. The slide rule in front of us, which can slide in the center, is a high-end product. Square roots, trigonometric functions, exponentials, logarithms, and so on can all be performed on this ruler.

Back then, we manufactured mushroom bombs using a few hand-cranked calculators and a large number of slide rules.

I had only met Qin Liang when I was in school. After I started working, I was lucky enough to be assigned to a calculator, and then to a computer...

"Teacher Sha, I..."

"Don't know how to use it? I thought you were omnipotent, but it turns out there are things you don't know. Come on, I'll teach you. You can't do scientific research without knowing this..."

As darkness fell, two figures emerged from the library, rubbing their heads.

"That classmate was absolutely right, he's simply a prodigy!"

"Ahem, Zhu Yongguang, we are college students, we can't use foul language. I think that classmate must be a graduate student, otherwise, how could he know so much?"

"A graduate student? Zhao Ergang, you must be mistaken. That classmate looks very young to me."

Zhao Ergang smiled and said, "I hope I'm wrong. He looks like he's not even eighteen yet. But... what if he's from the city and hasn't suffered, which makes him look young?"

"Hmm, maybe. Let's go to the nearby canteen and get two steamed buns and some pickled vegetables to take back and eat!"

Dormitory 13, Room 308.

crunch...

The wooden door was pushed open, followed by a click as the light cord near the door was pulled, and the light bulb in the center of the dormitory ceiling lit up.

"Hey, a new student moved into our dorm?"

Zhu Yongguang and Zhao Ergang were both very curious to see that the previously empty upper bunk by the window had been covered with brand new bedding.

"Yeah, who is it that comes at this time? Could it be someone who used connections to get promoted?"

The two exchanged a glance, then said nothing more.

Eating, reading, writing papers, time slowly passed. At ten o'clock, just as the dormitory building was about to close, someone finally pushed the door open.

"Sigh, this is only the first day, and they're already treating people like animals!"

Six eyes met, followed by gasps of surprise.

"Why is it you (the people)?"

(End of this chapter)