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

Chapter 80 The Double Delta Wing Encounters Technical Challenges

"Old Yang? What brings you here?" Professor Sha asked curiously. "Liangzi's calculator is for us project people. You mechanical engineering students shouldn't even think about getting your hands on it!"

"Old Sha, what are you saying? Aren't the fourth and fifth departments all part of the Northwestern Polytechnical University family? Some of the teachers in the fifth department are even the spouses of the teachers in the fourth department. We're all intertwined..."

"Old Yang, stop! Life is life, and work is work..."

Just then, Qin Liang took out a calculator, and then, feeling it wasn't enough, took two more, placing the three calculators in Professor Yang's hands: "Professor Yang, here you go!"

"Okay, thank you. Look at Liangzi, he's so supportive of the work of our Northwestern Polytechnical University professors!" Professor Yang: "Liangzi, I heard that the Department of Computer Science is developing a computer using the 8086 chip. Do you think you could..."

"No, the computers made with the 8086 chip are for our Department 5. What would your Mechanical Engineering Department need the 8086 for?" Professor Liu rolled his eyes at him. "Old Yang, I'm not trying to be mean, but getting three calculators is already pretty good. Do you know how much each one costs? There aren't any in China. They were bought with foreign exchange!"

"Professor Yang, what do you need 8086 for?" Qin Liang asked.

"Hmph, I'm not talking to you guys, you're all up to no good! Liangzi, our fourth department is currently researching using computer-controlled machine tools for processing, which could reduce workload and improve precision, but it's still just theoretical, since we don't have computers yet..."

Why don't you just go directly to the First Department?

"Sigh, I went there, but I was kicked out by the First Department..." Professor Yang was a little embarrassed. He was kicked out by the First Department. The 8086 chip had just been exported when it was rejected!

There were only one hundred sets to begin with. The Electronic Engineering Department took ten sets to replicate the radar, leaving only ninety sets. There aren't even enough for everyone in the Computer Science Department to have one set, so how could it be your Mechanical Engineering Department? You're dreaming, actually wanting to add computers to machine tools!
He could only turn to the Fifth Division, since those 8086 chips were given to the First Division by the Fifth Division! These old colleagues were very direct, but thankfully, Qin Liang was very polite!

“Okay, Professor Yang, I can call them and ask them to allocate ten sets to you, but... I also have a request.”

"Tell us, whatever your request, we'll grant it!"

"You need to develop a CNC milling machine within three months to meet our processing needs!"

Multi-functional machining centers, especially those with automatic tool changers, are out of the question. Three-axis, five-linkage machining centers are also out of the question. At this stage, a CNC milling machine is good enough, the key is that the precision must be high enough. From what I remember, there was a process in machining double delta wings that troubled Factory 132 for a long time: the leading-edge motorized flap actuator cylinder. If the machining precision of this part wasn't high enough, it would jam and become unresponsive. Now…

"Okay, no problem! We've already researched this type of device, but we lacked the hardware. With the chips, we can make it within a month!"

"Okay, then I'll wait!"

Factory 132.

Inside the huge assembly plant, countless workers are busy at work. Dozens of workers stand at each workstation, installing the structural frame in full swing, their faces beaming with smiles.

This is a multi-million dollar business deal! The factory finally has money! Every day when I go home, I can get a bonus!
Next to the final assembly plant are various machining workshops, where parts are produced according to the production drawings and then sent to be assembled. There is also a trial production workshop.

The lathe hummed as wires flew off the workpiece. Soon, a cylindrical product began to take shape. The technician picked up calipers, took several measurements, and made continuous adjustments. Finally, satisfied, he picked up sandpaper and polished the workpiece while it was rotating.

"All done!" "Master Liu, you really are a master craftsman, your skills are top-notch!" The technician next to him took the last flap actuator tube, put it on the trolley, and pushed it into the wing assembly workshop next door. Most of the production was of delta wings, but there was only one workstation where the outer edge of the wing had changed significantly.

"Mr. Tu, you're here too?" The technicians were overjoyed to see Mr. Tu.

"Yes, come and take a look. Right now, we need to focus on both production and the development of new aircraft. We can't let either of them be delayed. Once the actuator is installed, let's get on with the wing flutter test!"

"it is good!"

That afternoon, at the flutter laboratory.

"Attention, speed 100 meters per second, experiment begins!"

The wings, which were fixed to the workstation, began to visibly sway.

"This...this shouldn't be happening!" Everyone frowned.

When an aircraft is flying in the air, the interaction between aerodynamic effects and the elastic vibration of the structure will cause the aircraft to enter a self-excited vibration state. As the vibration continues to increase, it may shake off the wings or even cause the entire aircraft to crash.

At a certain speed, an aircraft will experience flutter. As long as this speed exceeds the aircraft's maximum speed, it is considered to have achieved flutter.

For an aircraft capable of flying at Mach 2, it needs to maintain a speed of at least 500 to 600 meters per second to fly normally, which is simply not possible now!
That evening, in the conference room.

"In the entire East, we have never developed a completely new aircraft. Even the J-8 is just a larger version of the twin-engine J-7. Modifying the wings now is not so easy."

"Yes, a double delta wing—very few have developed one in the world. Northwestern Polytechnical University is just using computers to calculate it, which is seriously out of touch with reality. I'm afraid..."

Tu Lao looked at everyone with a complicated expression: "Everyone, developing a brand new aircraft will definitely involve various difficulties! Are you all bowing down to these difficulties with your current statements? If you have this kind of attitude, then you'll never be able to start any new projects!"

“Old Tu, we’re just an aircraft factory, we don’t have this kind of experience. Now, should we go to Northwestern Polytechnical University…” Engineer Lu suggested from the side.

Before Old Tu could answer, the door outside was pushed open.

"Old Tu, news has come from the wind tunnel in Sichuan Province. Using the 1:1 scale model we recently sent over, they discovered that as the angle of attack of the aircraft increases, airflow separation will occur on the outer wing of the double delta wing, which will have an adverse effect on the pitch stability of the entire aircraft!"

The previous models were all fine when they were sent over. This time, after receiving all the design drawings from Northwestern Polytechnical University, they made a one-to-one model and sent it over again to continue the wind tunnel test, and that's when they discovered the problem!
The development of the double delta wing has once again encountered severe challenges!

"It seems we'll have to invite the faculty and students from Northwestern Polytechnical University over." Professor Tu took a deep breath. "Send a telegram immediately!"

(End of this chapter)