F-18 relies on the resin matrix composite materials used in manufacturing to achieve immunity to incoming electromagnetic waves, so that electromagnetic waves pass through the resin-based skin, which naturally has better low detectable performance than the aluminum-lithium alloy that Southwest Science and Industry is now preparing to use to replace resin materials.

One thing that must be known is that aluminum-lithium alloy is a typical conductive material, aluminum is the most common metal material on the earth, and most of the wires are even made of aluminum as the core material, which shows how good the conductivity of aluminum is, not to mention lithium, as the most potential new generation of battery manufacturing materials, the conductivity will be bad?

In this way, the new J-J made of aluminum-lithium alloy skin is inherently inferior to resin matrix composite materials in terms of low detectability, which is why decades later, countries are sparing no effort to develop composite materials to replace aluminum-lithium alloys, which is really driven by the basic requirements of military fighters for low detectability. There is no such demand on the civilian side, and even if the radar signal of the civil aircraft is low, it is necessary to install a corner reflector to amplify its own radar signal. so as not to lose contact.

Thinking of the use of aluminum-lithium alloy instead of F-18 originally used resin matrix composite materials by Southwest Science and Industry, I originally felt that I was on the right path, and it was not good all of a sudden, and now it seems that in terms of low detectable performance requirements, Southwest Science and Industry will even lag behind F-18 by a large margin this time?

At this time, Yang Hui was also in a state of confusion, but why didn't he pay attention to this aspect of the problem? If you had known earlier, Yang Hui must have started the pre-development of composite materials early on.

Of course, Yang Hui can't be blamed for everything, after all, no one is perfect, and Yang Hui, who was in the previous face, was not a fighter in the first place, but a guy who worked in the test flight institute. Although I have seen many types of fighters, and even know a lot of data on various types of aircraft in the Republic during the test flight work, if you want to ask about the manufacturing process of the aircraft and the more in-depth selection of materials, you can really only say that you are embarrassed, and it is not within the scope of Yang Hui's previous work at all.

Now I suddenly figured out the problem. Yang Hui must face this problem well, and even the Southwest Science and Industry Program that Yang Hui said just now can achieve the same RCS value as the F-18, Yang Hui is also a little difficult to guarantee, after all, the gap in stealth performance of this thing is really big.

As the developer of the program, Yang Hui must now put the problem on the table, find the problem now, and make the problem public, which must be done, if he is afraid of affecting the bidding of the program now. Knowing the problem but hiding it and not reporting it, Yang Hui will never be able to do it.

"However, we now have a problem that must be made clear, in view of the huge gap between our domestic composite materials and the United States, our plan chose to abandon the use of resin matrix composites, in order to achieve the same weight reduction effect of resin matrix composites, we chose to use aluminum-lithium alloy instead of the original aluminum-magnesium alloy, in terms of mechanical properties, we fully use aluminum-lithium alloy instead of aluminum-magnesium alloy. The weight reduction effect of the whole machine will be better than that of most of the F-18 using aluminum-magnesium alloy, and some resin matrix composites. ”

It is certain that the Southwest Science and Industry program will be weaker than the stealth performance of the F-18. But there is also skill in saying it, you must first talk about the benefits of this thing, and it can also make it easier for the army to accept it in the future, especially when Yang Hui just blew so much, this kind of method of suppressing the desire to promote first is even more necessary.

And the army really eats this set, and I heard that Southwest Science and Industry can make a good thing that is comparable to the weight reduction performance of resin matrix composites. It's not fun here, this kind of breakthrough in the basic materials for making aircraft is no better than other things, this is a good thing that can benefit all the aviation manufacturing industry, as long as the thing comes out, not only the current new J can benefit. Even the current No. 10 project can also benefit greatly, and the good thing of weight loss is quite tempting. The existence of confusion.

"Is that true? Can you come up with a new generation of aluminum-lithium alloys that are comparable to resin-based materials that meet the weight reduction properties of materials? Why doesn't our army know about this, you can all be regarded as knowing and not reporting it! ”

Hearing Commander Liu's words, Yang Hui just smiled.

"Things must be true, this is our joint project with Guiyang Aluminum-Magnesium Alloy Design and Research Institute also located in the southwest region, this research institute and our southwest science and industry has many years of business dealings, established in 58 years, speaking of history than our southwest science and industry is a little earlier, technically affirming the existence of domestic first-class, now they have begun the research on the international mainstream of the third generation of aluminum-lithium alloy under laboratory conditions, and the second generation of aluminum-lithium alloy has a small-scale production capacity."

Yang Hui's explanation made the army even more confused, this Guiyang Aluminum-Magnesium Alloy Research Institute is registered in the whole country, and has made such a big breakthrough, why the army doesn't know, this technology is related to the existence of the army's combat effectiveness.

However, it is not the military that asks the question first, and the Science and Technology Commission pays more attention to the breakthrough of this basic national defense material than the military.

"And what's going on? Why doesn't our science and technology commission know anything about it, and I remember that the state has never had a scientific research project on the research of aluminum-lithium alloy materials, right? Don't hurry up and tell me what's going on, you have to give me an honest answer about this, it's only been a few years, you, the southwest science and industry, have made such a big breakthrough, I need to go to your side one day to surprise check it, and see how many good things your kid has hidden! ”

Listening to Director Ding's words, Yang Hui also had a headache, this is obviously a little crooked, what Yang Hui wants to say is not what the Science and Technology Commission wants to ask now, answer it briefly immediately, or go back to the topic.

"This project is invested by our Southwest Science and Industry to Guiyang Aluminum-Magnesium Alloy Research Institute, funded by our Southwest Science and Industry, they contribute to the research, and our ultimate goal is the third generation of aluminum-lithium alloy, so the results have not yet been reported. But we must be preparing to use this new alloy on the new J-18 to reduce weight, and now there is a big problem, the performance of the aluminum-lithium alloy in terms of low detectability is not as good as the resin matrix composite used in the F-18. ”

Finally said the problem, Yang Hui was also relieved in his heart, and now it depends on what the army says. But no matter what, Yang Hui knows that there is definitely nothing wrong with Xinj's use of aluminum-lithium alloy, and now it is more just a notice, after all, there is definitely no better solution in China except for aluminum-lithium alloy.

And the army and the Science and Technology Commission obviously know the situation in China, it would be good to have aluminum-lithium alloy, what kind of bicycle do you need!

"There's no problem with that, it's just not known how big the low detectability performance gap is between the two materials. Although it is certain that the use of aluminum-lithium alloy to build fighters is, we want to know where the specific gaps are, so as to facilitate our subsequent technical evaluation. ”

The review team wants to conduct a technical assessment, Yang Hui can understand, and to say that the performance gap between the two materials, in fact, is not a world of difference, if the resin matrix composite material can really do no radar signal echo, then the PZ-1 artillery reconnaissance drone made by Southwest Science and Industry with civilian-grade plastics is not against the sky?

And it turns out that the UAV made of plastic by Southwest Science and Industry has not been completely stealth, and after the radar is irradiated, there will also be a certain radar echo.

"There must be a gap, resin matrix composite materials can not make the aircraft completely stealth, composite materials do not conduct electricity will not produce secondary radiation, the radar waves emitted by enemy aircraft directly penetrate the resin-based material skin, but in the skin of the aircraft are all metal, non-metal, oil and other things, the radar waves that pass through the skin will also produce secondary radiation after encountering these things in the wings, and the secondary radiation generated by these things will also expose the position of the aircraft itself."

Yang Hui can still figure out the advantages and disadvantages of this resin matrix composite, combined with the actual radar test data of PZ-1, after careful thinking, he can draw a preliminary conclusion, and even Yang Hui continued to analyze the reason why the resin matrix composite can achieve low detectable performance.

"Of course, the resin matrix composite material does not conduct electricity, and it seems to be transparent to radar waves, but radar waves will cause the onboard equipment inside the wing to produce secondary radiation echoes, which are not at all small, so the low detectability of the F-18 should not be so good. In fact, the real principle of resin matrix composite material is that it can effectively suppress and weaken the radar wave when the radar wave penetrates, which is the reason why it can really achieve good low detectability, and it still has some gaps compared with the real stealth absorbing coating. (To be continued.) )