Chapter 528 You don’t understand? Then I have to take out the information
It can be said that the wing-body fusion is not simple, and you can’t just look at the literal meaning!
"Boss Gao, what are the side wings you are talking about?"

Gao Zhendong was a little confused. Logically speaking, the wing strips had appeared in the 50s and were not a new thing in later generations, so Gao Zhendong just mentioned it and did not explain it in detail.

"Hiss... this... wait a minute."

I don't understand, but I thought he did. But he doesn't understand, but he thought I did. What should I do? Waiting online, urgent!
Fortunately, Gao Zhendong was prepared. System, start!
He opened the system and searched for a book. It was a thick book with more than 1300 pages of text. Fortunately, the system counted by book instead of page, otherwise this book plus the "Steel Materials Handbook" would make Gao Zhendong's number of lottery draws even longer than the total of two years.

found it!
This is a magical book about the aerodynamic layout design of aircraft. The book in Gao Zhendong's hand was completed in 1996, just before the outbreak. Many environmental conditions, understandings and habits are relatively close to those of the 60s.

This book discusses the design of the entire aircraft's aerodynamic layout. The most interesting thing is that for a lot of the content, it does not provide theoretical calculations and formulas, but observation results and experience.

Aerodynamic layout is something that cannot be calculated purely by theory. A considerable part of the theory in this field can be roughly understood as experience with formulas, which is more reliable. Everyone is working with things like the unconclusive NS equations, so no one can accuse others of relying on guesswork.

If fluid mechanics could be calculated theoretically, the Citigroup's hypersonic missiles wouldn't have to go up and down endlessly.

In a way, part of this book is not about teaching people how to calculate an airplane, but about teaching people how to "put together" a suitable aerodynamic shape.

For example, in the part of winglets, there are very few formulas and theories mentioned in this book. Instead, it tells readers what the state of a certain configuration is at a certain angle and speed, and then draws the typical condition-response curve.

With these data and images, readers with a basic understanding can naturally form certain boundary conditions, answer multiple-choice questions within these boundary conditions, or use trial and error.

Don’t underestimate these boundary conditions, they can save designers a lot of trouble.

For example, although there are many inputs and outputs that are not linear, once there is a boundary and they are separated, they can be processed approximately linearly.

For example, if you know that at a certain angle and under certain conditions, the performance will deteriorate to an unacceptable level, then just do things under these conditions and try to gain as much benefit as possible within this range.

By the way, the most famous application of Attack-5, the area law, is also included in this book.

Gao Zhendong collected this book in his previous life and would read it whenever he had time. This was the reason why a considerable part of this book could be read with great interest without the need for professional background knowledge.

Seeing Gao Zhendong not saying a word, Mr. Xiao thought that Gao Zhendong was dissatisfied with something, but it didn't seem like that. While he was wondering, Gao Zhendong had already got what he wanted.

He stood up and said to Mr. Xiao, "Mr. Xiao, please wait a minute. I'll go get some information. It may take some time. Don't worry, I'll be back soon."

After saying that, he turned around and walked out of the reception room, returned to his office, sat in the office for about twenty minutes, and produced a stack of information in his hand, about 80 pages, a carbon copy of Gao Zhendong's handwriting.

So much time was spent mainly because some content had to be deleted, such as the names of Citigroup planes that were all over the page.

This part basically explains all of Citigroup's early research results on winglets. When conducting these studies, Citigroup had no relevant theories, and its main purpose was to work hard and make miracles happen, so it tried one thing after another.

How thorough were the Citigroup tests? Two numbers can tell the story: they tested more than 200 types of edge strips and matched the main wings with at least five different sweep angles!
Thanks to the gift from Citigroup! We must thank Gao Zhendong, he is not the kind of person who will not admit his debt even though this book was written by a Chinese.

In the reception room, Mr. Xiao had been waiting patiently. After hearing what Gao Zhendong said, he realized that Gao Zhendong had the goods, so he had to wait resolutely.

But he was very curious about where Gao Zhendong got this information. He definitely didn't have it in China, so could it be from abroad?
Out of curiosity, he waited for Gao Zhendong to come back. The other party sat down in front of him happily and handed him a stack of papers.

"Mr. Xiao, these are some things related to the wing slats that I calculated using a computer in my spare time. You can take a look at them when you have time. As for the wing slats, I will only give you a general idea of ​​the situation. It's good for you to have a general idea in your mind for now."

Once we have a concept, we can discuss it. As for the specific details, that is something that will enter the design work.

Here, Gao Zhendong directly said that the relevant content of the wing strip was calculated by himself because he was bored. This is at least reasonable. As the de facto number one figure in domestic computers, he is somewhat different from ordinary people in computer application. Isn't this reasonable?

If you say that it was observed in an experiment, that's nonsense. No one would believe it. The wing slat is a typical vortex lift enhancement method. It can effectively increase the lift at high angles of attack. It can be said to be a very successful aerodynamic design. Except for the large swept delta wing aircraft, there are very few third-generation aircraft that do not use wing slats.

Seeing Mr. Xiao's happy face, Gao Zhendong did not forget to remind him: "Mr. Xiao, every advantage has its disadvantages. The wing slats have a certain impact on the stability of the aircraft. The specific choice depends on the trade-offs."

However, the impact is not so great that the aircraft cannot be used without fly-by-wire control and relaxed static stability technology. For Mr. Xiao, it is definitely worthwhile to be able to improve the lift at high angles of attack to a certain extent.

At this time, Mr. Xiao, who was happy, finally realized what he had said just now. Did he calculate this on the computer himself? This is the real brain.

As for his entourage, they were speechless. How could this guy be squatting in a steel rolling mill of the 17th Ministry of Machine Building? It was nonsense.

Gao Zhendong then pointed to the data and said, "These data are calculated. I suggest that you first select some of the typical examples I listed above and do wind tunnel tests to see how credible they are before moving on."

In fact, the Citigroup guys had already done the experiment 20 years later, so this may sound a bit awkward.

As for this reminder, Gao Zhendong must say this, otherwise it would not be rigorous enough. At this time, we still have low-speed wind tunnels and transonic wind tunnels, and we have the conditions for wind tunnel testing.

With this material, and some wind tunnel testing, it should be possible to find a side strip that's suitable for Mr. 5.

Mr. Xiao nodded repeatedly. This was certain. No one would dare to move forward without first conducting experiments on theoretical calculations.

But leaving aside the accuracy of the "calculation results", there are a lot of conceptual, summary and declarative content in it, which was very inspiring to him. It turns out that this thing can be done this way?

Worth it! Let alone the wing-body fusion, the wing strip alone is worth the ticket price for this trip to Beijing. Mr. Xiao was very happy.

Thinking of this, Mr. Xiao remembered that he had interrupted Chief Engineer Gao before he finished his first suggestion on wing-body fusion.

"Boss Gao, I roughly understand your first consideration. This suggestion does require very little change to the aircraft structure and the cost is not high. So what are its other shortcomings?"

"The first defect was mentioned earlier, the sealing problem of the wing installation."

"Well, it's not a big problem. If it doesn't work, just apply putty. Every time you dismantle the wing for maintenance, just scrape it off and apply it again."

Gao Zhendong was stunned by what Mr. Xiao said. Damn, I really couldn't think of this solution. I just thought about how to solve the problem with technology and even thought of high-viscosity and high-strength tape. I didn't expect that Mr. Xiao didn't take it seriously at all and solved it with technology.

Learned, learned, engaged in applied research, life is full of learning, there are surprises at any time. Gao Zhendong thought, yes, the Citigroup can do it, but we can't? The Citigroup's F-22 is often puttyed, and the quality of the putty is not very good, and it is obviously cracked.

We often use this method when conditions are bad. Our first early warning aircraft was equipped with a turboprop engine. The engine change caused the aircraft to have a deflection torque, which was very difficult to solve. Our solution was to pre-bias the joystick by 8 degrees to offset this deflection torque.

Although the early warning aircraft was not developed in the end, the problem was indeed solved by this simple method.

"The second defect is that this is a patchwork on the original structure. The benefits of wing-body fusion in enhancing the rigidity of the fuselage and reducing the weight of the structure are basically gone. In addition, the increased space is also limited by the original structure. If a fuel tank is to be built, there may be some difficulties in its layout."

If we repair the original structure without redesigning the main load-bearing structure, then it won't be that much trouble in design, no matter what wing it is, but the benefits will not be as complete.

"Well, this is indeed a problem, but it's not that bad. If we put the equipment here, then other places where equipment is placed can be used for other things. It's just that the adjustment will bring some workload. If the benefits are sufficient, such as the improvement of lift-to-drag ratio, the reduction of drag, and the increase of volume to a certain extent, it is not unacceptable. I just don't know how to estimate this benefit."

Mr. Xiao pondered and said that, in general, he felt that although this method was simple, it was not hopeless. He just didn't know how to estimate the benefits it would bring.

Hearing him say this, Gao Zhendong took out another stack of papers: "This is some of the things I calculated about wing-body fusion when I was free. If Mr. Xiao is interested, you can refer to it."

(End of this chapter)