Chapter 528: You don’t understand either? Then I had to dig out the information
Let’s just say that this wing-body fusion is not simple, and you can’t just take it literally!
"Mr. Gao, what are the side strips you are talking about?"
Gao Zhendong is a little confused. It is said that the side strips appeared in the 1950s and are not a new thing in later generations, so Gao Zhendong just mentioned it without giving a detailed explanation.
"Hiss...this...you wait."
I didn’t understand and I thought he understood, but he didn’t understand and thought I understood. What should I do? Waiting online, urgent!
Fortunately, Gao Zhendong is prepared, the system is activated!
Open the system and search for a book in it. It is quite a thick book with more than 1,300 pages of text. Fortunately, the system counts by book and not by page. Otherwise, this book can be added to the "Steel Materials Manual" Gao Zhendong's number of draws in two years combined is not enough.
Found it!
This is a very magical book, about the aerodynamic layout design of aircraft. This book in Gao Zhendong’s hand was written in 1996, just before the outbreak was about to occur but had not yet occurred. Many environmental conditions and The understanding and habits are relatively close to those of 60 years.
This book explains the design of the entire aircraft aerodynamic layout. The most interesting part is that in many contents, it does not give theoretical calculations and formulas, but observation results and experiences.
Aerodynamic layout 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 inconclusive. Things like NS equations are doing their job, and no one can say that they are relying on deception.
If fluid mechanics could be calculated clearly theoretically, Citigroup's hypersonic missiles wouldn't go up and down endlessly.
To a certain extent, part of this book is not to teach people how to calculate an airplane, but to teach people how to "make up" a suitable aerodynamic shape.
For example, in the side wing part, there are very few formulas and theories mentioned in this book. Instead, it tells the readers what the configuration is like at which angle, at which speed, and then describes the typical The condition-response curve is drawn.
Relying on these data and images, readers with basic knowledge can naturally form certain boundary conditions, do multiple-choice questions within these boundary conditions, or continue trial and error.
Don’t underestimate these boundary conditions, they can save designers a lot of work.
For example, there are many inputs and outputs. Although it is not linear, once there is a boundary and divided, it can be processed approximately linearly.
For another example, if you know that the performance will deteriorate to an unacceptable level under certain conditions at a certain angle, then you should do things directly under these conditions and maximize the benefits within this range.
By the way, the most famous application of G-5, the area law, is also in this book.
Gao Zhendong would collect this book in his previous life and would read it when he had nothing to do. For this reason, quite a few parts of this book do not require professional background knowledge to read with gusto.
Seeing Gao Zhendong not saying a word, Mr. Xiao thought Gao Zhendong was dissatisfied in some way, but it didn’t look like it. In the midst of doubts, Gao Zhendong had already prepared what he wanted. .
He stood up and said to Mr. Xiao: "Mr. Xiao, wait a minute. I'm going to get some information. It may take a while. Don't worry, I'll be back in a moment."
After saying that, he turned around and walked out of the reception room, and returned to his office. After sitting in the office for about 20 minutes, a stack of information appeared in his hand, about 80 pages, a carbon copy of Gao Zhendong's handwriting.
It took so much time, mainly because some content had to be deleted, such as the entire article about the names of Citigroup’s planes.
This part basically explains all the results of Citigroup's early research on side strip wings. When doing these studies, Citigroup didn't have any relevant theories. The main idea was to work hard to achieve miracles and try the same thing.
How solid was the Citigroup experiment? Just two numbers can illustrate it - they tested more than 200 kinds of edges! It is equipped with at least 5 different main wings with different sweep angles!
Thanks Citizen for the gift! You must be grateful when you deserve it. Gao Zhendong is not the kind of person who refuses to admit his mistakes even though this book was written by someone from China.
In the reception room, Mr. Xiao has been waiting patiently. After hearing Gao Zhendong's words, he realized that Gao Zhendong had goods in hand, so he must wait resolutely.
But he was curious, where did Gao Zhendong get this information? It must not be available in China. Could it be abroad?
With curiosity, he waited until Gao Zhendong came back. He happily sat down in front of him and handed him a stack of paper.
"Mr. Xiao, these are some things related to the side strips and wings that I used computers to calculate in my spare time. Please take a look at them when you have time. As for the side strips and wings, I will only briefly talk about the situation here. You can Just have a concept in mind for the time being.”
Once you have a concept, you can discuss it. As for the specific details, that is a matter of entering into the design work.
Here, Gao Zhendong directly said that the relevant content of Bian Tiaoyi was calculated by a computer when he was too free. This is at least somewhat reasonable. As the de facto number one figure in domestic computers, he is somewhat different from ordinary people in terms of computer applications. Is this reasonable?
If it is said to be experimentally observed, it is nonsense, and no one would believe it even if it were killed. The edge strip wing is a typical vortex lift increase method, which can effectively increase the lift at large angles of attack. It can be said to be a very successful aerodynamic design. Except for large swept delta wing aircraft, there are very few third-generation aircraft that do not use edge strips. .
Seeing the joy on Mr. Xiao’s face, Gao Zhendong did not forget to remind him: “Mr. Xiao, there are advantages and disadvantages. The side strips have a certain impact on the stability of the aircraft. The specific details still depend on it. Trade-off. ”
But this impact is not so great that it cannot be used without fly-by-wire control and relaxed static stability technology. For Mr. Xiao, it can improve the lift at high angle of attack to a certain extent. It's an absolute bargain.
At this time, Mr. Xiao finally realized after he was happy, what did he just say? Did he calculate this on his own computer? This is the real most powerful brain.
As for his entourage, they couldn't even speak. How could this man be squatting in a steel rolling mill in the 17th Machinery Department? It's nonsense.
Then Gao Zhendong pointed to the data again: "These data are calculated. It is recommended to first select some of the typical examples I listed above and do wind tunnel tests to see how reliable they are, and then continue. . ”
In fact, the experiment with Citigroup had already been done twenty years later, which sounds awkward.
As for this reminder, Gao Zhendong must say this, otherwise it will not be rigorous enough. At this time, we still have low-speed wind tunnels and trans-supersonic wind tunnels, and we have the conditions for wind tunnel testing.
With this material and lots of exposure in the wind tunnel, it should be possible to find a side strip suitable for Mr. 5.
Mr. Xiao nodded repeatedly. This is for sure. No one dares to proceed with theoretical calculations without first doing experiments.
But putting aside the accuracy of the "calculation results", there was a lot of conceptual, summary, and descriptive content in it, which inspired him a lot. So it turns out that this thing can still be done like this?
Value! Not to mention the fusion of the wing body, this side wing alone is worth the price of this trip to the capital, and Mr. Xiao is very happy.
Thinking of this, Mr. Xiao remembered that Mr. Gao had interrupted him before he finished his first suggestion of wing-body fusion.
"Mr. Gao, I generally understand your first consideration. This suggestion indeed changes the body structure very little and does not cost much. So what are its shortcomings?"
“The first flaw has just been mentioned, 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 shovel it and hit it hard."
Mr. Xiao's words shocked Gao Zhendong, fuck, this I really couldn’t think of a way. I was just thinking about how to use technology to solve the problem, and my idea was all about high-viscosity and high-strength tape. Unexpectedly, Mr. Xiao didn’t take it seriously at all and used technology to solve it.
It is true to learn, learn, engage in applied research, and live to learn, and there will be surprises at any time. Gao Zhendong diverged his thoughts and said, yes, Citigroup can do it, but we can’t? Citigroup's F-22 was often put on putty, and the quality of the putty was not that good and it cracked obviously.
We often use this method when the conditions are not good. Our first early warning aircraft was equipped with a turboprop engine. The change in the engine caused the aircraft to have a deflection moment, which was difficult to solve. Our The solution is that the joystick is naturally deflected by 8 degrees in advance, and this deflection moment is offset first.
Although the early warning aircraft was not completed in the end, this problem was indeed solved by this crude method.
"The second flaw is that this is a patchwork on the original structure. The benefits of wing-body fusion in enhancing the rigidity of the aircraft body and reducing the weight of the structure are basically gone. Moreover, the added space is also limited by the original structure. If we want If you want to make a fuel tank, there may be some difficulties in the layout. "
If you repair the original structure without redesigning the main load-bearing structure, it will actually be very troublesome in terms of design, no matter what kind of wing it is. No, it's just that the benefits aren't all that great.
“Well, this is indeed a problem, but it’s okay. If the equipment is placed here, the other places where the equipment is placed can be used for other things. It’s just that the adjustment will bring some workload. If the benefits are enough For example, if the lift-to-drag ratio is increased, the resistance is reduced, and the volume is increased to a certain extent, it is not unacceptable, but I don’t know how to estimate the benefits. "
Generally speaking, Mr. Xiao pondered. , he felt that although this method was simple, it was either in vain or he didn’t know how to estimate the benefits.
Hearing what he said, Gao Zhendong took out another stack of paper: "These are some things about wing body fusion that I calculated in my spare time. If Mr. Xiao is interested, you can refer to it. Reference.”
(End of this chapter)