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

Chapter 25 A stroke of genius
When Grumman took charge of the project, the engineers at Factory 132 were filled with admiration. Now... their surprised gazes are exactly the same as they were back then.

“Currently, the mainstream internationally is side air intakes and belly air intakes. What’s with your cheek air intake?” Old Tu said, “This idea is wildly imaginative. Qin Liang, quickly tell me what the benefits are!”

"Of course, it's about improving air intake efficiency under various conditions..." Qin Liang explained at length.

With air intake at the nose, there is no obstruction. With air intakes at the sides, one side of the air intake will be blocked when turning. With air intake at the belly, it will be blocked when diving. However, gravity helps during a dive, so there is no need to worry. Therefore, air intake at the belly is considered the best solution.

As for its drawbacks, it cannot take off from field airfield runways; if it ingests some debris, it might damage the engine. Also, the engine's fan blades are visible through the air intake, increasing its radar cross-section. Therefore, this type of air intake is rarely seen in the era of stealth aircraft.

The nose layout of stealth aircraft is largely the same, with a diamond-shaped cross-section and two air intakes underneath that are right next to the two sides of the diamond. In fact, it is quite similar to the current layout!
"Because the air intake is positioned low, it improves air intake efficiency at high angles of attack. At the same time, it won't be completely blocked when turning, ensuring sufficient air intake efficiency. Also, the landing gear at the nose doesn't need to be modified..."

"Turn the air intake down ten degrees, it's simply a stroke of genius!" Old Tu exclaimed. "How come we never thought of putting the air intake here, combining the advantages of various air intakes!"

“That’s right, this design is highly feasible! Next, we can complete the original design and then go to the wind tunnel…” Professor Sha was full of excitement.

All of this doesn't cost too much money. The calculations are done on paper, then a model is made, a wind tunnel is blown through, and modifications are made based on the wind tunnel results...

“Yes, that way, the space left in the nose can at least accommodate a 500mm radar, and its all-weather combat capability will definitely be much stronger than the J-73.” Old Tu nodded: “I’ll take this project to the Air Force and try to get a share of the J-73’s R&D funding! But…”

Right now, the word that everyone least wants to hear is "but," which means that there are still obstacles waiting for them!

“After this modification, the drag will definitely increase, so a more powerful engine is needed. The engine on the MiG-21MF is a model with increased thrust, and we can reverse engineer it,” Qin Liang said.

The J-7 has two engine options: the WP-7 and the WP-13. The latter has increased thrust and is actually a copy of the engine used in the MiG-21MF.

Now, with insufficient engine thrust, the best solution would be to replace it with an advanced Western turbofan engine, especially the F404, which would be a perfect match. Unfortunately, in 1978, that was out of the question!

The J-3 project involved reverse engineering the MiG-21MF, and the reverse engineering of the engine proved useful in this project! This made it easier for the leaders promoting the J-3 project to accept their own solutions, so they did do some worthwhile work!
"If the engine's thrust is still insufficient, we can find ways to increase it, such as using more advanced turbine blade materials to withstand higher temperatures..."

Qin Liang still had a lot on his mind, but he couldn't bring it up directly, otherwise he wouldn't be able to explain it! Anyway, this is something to talk about later, there's no need to rush now.

Old Tu nodded. This problem was solved, but... there was more than one problem!

"Qin Liang, and also..."

"As for the airborne radar issue, that's beyond our consideration, but we don't need to worry about it either, since there are supporting manufacturers!"

For decades, airborne radar technology in the East has stagnated. Although the 607 Institute, which specializes in airborne radar, was established, it took many years to develop a single-pulse radar rangefinder. As for more advanced pulse Doppler radar, forget about it.

However, Qin Liang wasn't worried. The 1980s were a honeymoon period between East and West, and they could acquire relevant technologies from the West! As an OEM, they didn't need to worry about supplier relationships for the time being…

“Director Luo, Qin Liang is a talented person, let him join our factory!” Old Tu exclaimed again. “No way!” Director Luo immediately refused: “Qin Liang didn’t go anywhere else before graduation, he stayed at Northwestern Polytechnical University! Old Tu, do you have any other questions?”

Qin Liang has already learned to answer questions quickly! It seems that no matter what difficulties he encounters, this young man can always find a solution. Indeed, the future belongs to the young!

Such an outstanding young person should definitely stay at Northwestern Polytechnical University for four years, and preferably pursue a master's degree, so that he can bring back many projects to Northwestern Polytechnical University!

Old Tu shook his head: "No more!"

"Great!" Qin Liang breathed a long sigh of relief. "Everyone, can we adjourn the meeting now? I need to get some sleep."

My eyelids are so heavy I can barely keep them open! Qin Liang's quick answer was just a way to end the meeting quickly so he could get some sleep! He doesn't dare go back to the dorm; he'll just have to spend the night here!

"still have a question."

Qin Liang looked at the person who spoke: "Teacher Liu, can't we talk about the problem tomorrow?"

"No," Professor Liu said. "What needs to be done today must be finished today!"

"it is good……"

"Even if we use Green's function to calculate the aerodynamic layout, the computational load is still too large! Not to mention, there are subsequent calculations for structural strength, flight quality, performance, flutter, and so on. We simply can't handle all of that with just a few people..."

“Then let’s use a computer…” Qin Liang walked towards his sleeping spot: “Professor Liu, tomorrow, tomorrow we’ll discuss using a computer for the design. Don’t worry, I’m quite familiar with computers…”

After Qin Liang finished speaking, he yawned, and then... started snoring.

"As for our university's computer science..." Professor Liu wanted to say something more, but seeing that Qin Liang was already fast asleep, he could only shake his head helplessly: "Alright, we'll wait until tomorrow!"

Qin Liang was really tired and slept until dawn. When he opened his eyes, he saw other people working.

"You guys...didn't sleep last night?"

"We need to come up with a concrete plan as soon as possible, and then report to the capital. Time waits for no one!" Old Tu sighed.

You just gave me an idea and then went to sleep, but the rest of us stayed up all night, working on the specific design plan. We've drawn a whole stack of sketches!
"Qin Liang, wash up, and then we'll go to the math department!"

(End of this chapter)