Since I had to work the next day, the reception did not last too late, and the wine was very restrained.

The vast majority of people still maintained a very clear consciousness when they left, such as Sun Huizhong, the deputy chief designer of the 648 Institute who flew from Zhucheng to Rongcheng yesterday afternoon.

He didn't speak the whole time just now, just quietly listened to Chang Haonan explain to other people's questions.

Although he had heard about the deeds of this young genius from many channels, Sun Huizhong felt that he still had to see it with his own eyes.

So now, the only chief engineer of the 648 Institute has only admiration left in his heart.

"Permanent worker!"

After leaving the guest house, Sun Huizhong called Chang Haonan from behind, and then quickly followed:

Chang Haonan turned his head and saw a man with half-white hair standing behind him.

"Are you ......?"

Although he has done a lot of things, he has only been here for half a year, and he has not had time to contact too many people.

In his previous life, as an ordinary military engineer, he also had limited connections, so except for a very few thunderous bigwigs, most of the faces were unfamiliar.

"Sun Huizhong, from Zhucheng 648."

The two shook hands under the dim streetlights.

After taking a closer look, Chang Haonan found that the other party's age did not seem to be particularly old, it should only be at the level of his early thirties, and the reason why he was bald early was probably just because of congenital reasons or too much pressure.

"Chang Gong, I would like to ask some more questions about the follow-up matching."

After all, it was very late, and Sun Huizhong lived in a guest house, and he didn't go in the same direction as the dormitory, so he didn't make any detours, and directly explained his intention.

This kind of thing Chang Haonan naturally will not refuse:

"Please."

"We want to develop a two-seat model based on the J-7F."

Sun Huizhong does not shy away from the idea of borrowing ideas from brother units, after all, the total number of design teams in the 648 Institute is only three digits, and the experience and level are also indescribable, so it is not ashamed to choose to copy homework in this case:

"But I heard from the comrades here in Rongcheng that the J-7F's air intake and front fuselage are integrated designs completed by you, and the modification of the fuselage will seriously affect the air intake efficiency, so I want to ask, what do you think is the feasibility of this plan?"

"That's true, the high air intake efficiency and stability of the J-7F is based on a compression of the incoming flow by the nose part, and if you want to change the two-seater, it is inevitable to make a major change to the front fuselage, which almost needs to tear down the entire design."

Changing from a single seat to a two-seater may seem simple, but it is not a small amount of work to operate.

For smaller aircraft, having an extra pilot can have a noticeable impact, and the more sophisticated the aerodynamic design of the aircraft, the less room will be left for such changes.

Both sides of the J-7F are occupied, which is particularly troublesome.

So after Chang Haonan thought about it for a while, he quickly gave his opinion, although this is a basin of cold water:

"When I designed this model, I just wanted to give the J-7 a real sense of over-the-horizon combat capability, and I didn't want it to take on more complex functions, so I didn't leave any margin, change the two-seater...... Personally, I'm not optimistic. ”

At that time, he had just crossed over, and he just wanted to quickly make a short and quick project to attract the teacher's attention, so as to quickly participate in the specific model project.

In fact, Chang Haonan still hasn't figured out how he stepped over Professor Liu Hongbo's layer and directly attracted Du Yishan's attention.

All in all, the end result was much better than expected.

"That's ...... so"

Sun Huizhong, who was standing opposite, lowered his head slightly, revealing an expression of regret:

"We were going to further improve the J-7, and we are currently doing the pre-research work of wing selection and air inlet matching, and after coming into contact with the J-7F project, I thought we could have a better reference, but unfortunately ......"

As soon as the other party said this, Chang Haonan suddenly remembered the conversation between him and the two pilots of the 25th Regiment of Hainan Airlines at the J-8C delivery ceremony.

They have said that there is a shortage of a good high-level trainer in the troops.

To solve this problem, it is of course the best way to design a new advanced training aircraft from scratch, but at present, there is no such solution in terms of funding or technology.

Not to mention anything else, two small-thrust or medium-thrust turbofan engines will not be available.

And there is not so much money at the moment.

However, it is still feasible to use the redundant digital fly-by-wire technology of the J-8IIACT, combined with the turbojet-14 with medium thrust and excellent performance, to change a model on the basis of the J-7.

The final product of this idea in later generations was Coach 9, which happened to be the product of 648.

And Chang Haonan is fully capable of making it born ahead of schedule and ......

Got even more perfect!

Therefore, he changed his words and said to Sun Huizhong, who was already preparing to say goodbye:

"If you have such an idea, you might as well be bolder."

Hearing this, the latter's eyes suddenly lit up, and he raised his head to look at Chang Haonan:

"You also think we need a new advanced trainer?"

Although the plan based on the J-7F technology has been denied, Sun Huizhong is quite happy to be able to get the affirmation of this training aircraft idea.

You must know that the conversion rate of pre-research results is actually very low, and sometimes only two or three of the 10 pre-research plans end up forming a formal project that can be carried out, and even fewer of them may eventually achieve positive results.

The two pre-research reports they submitted before were both rejected because of lack of depth.

Therefore, the 648 Institute also has concerns about the plan of this new advanced training aircraft-

It will take more investment to continue with the head-on, and no one dares to pack a ticket to say that the army will definitely want it, which is a risk for them with small families and small businesses.

Even Sun Huizhong, who originally proposed the idea, did not have much confidence.

You must know that although he has the title of deputy chief designer of the 648 Institute, it is entirely because there are really no talents in the institute that he is a person who is less than 30 years old and has not led any model design.

If you are young and have no successful experience, you will naturally lack confidence.

So when he heard Chang Haonan's supportive attitude, Sun Huizhong was quite excited.

Although the former is younger, judging from the situation at the dinner just now, he is definitely a real talent, and he has played a very important role in the 83 Project, and his statement is definitely weighty.

"Of course, you did it with Annihilation 7, and you should be well aware of the flaws."

Chang Haonan nodded, and did not show mercy because the person in front of him was from the 648 Institute:

"The low-speed performance and rear-seat vision are too poor, and the instructor even needs to make a self-made periscope to observe the situation ahead when taking off and landing, and the potential is not enough, and the training of J-7 and old J-8 pilots is barely enough, but our Air Force is making great strides into the era of third-generation aircraft, so this model will definitely not be able to pick up the girder for a long time."

As a matter of fact, the Jianjiao-7 model was supposed to only play a transitional role, and after entering the new century, it would gradually be replaced with a new type of training aircraft.

But like many other equipment in this era, it transitioned into the main equipment.

For various reasons, the planned new training aircraft has never been in place, and in the end, the Jianjiao-7, as a basic second-generation aircraft in nature, has been produced until 2017......

"Alas...... That's right. ”

Sun Huizhong sighed lightly:

"With your words, when we continue to engage in pre-research, we can be more or less sure-footed."

"You just said that you are currently doing wing selection and air inlet matching, what is the specific progress?"

Coach 9 is not a star model, Chang Haonan only knows that the original timeline was not officially put into service until 2011, and he does not know much about the research and development process.

"At present, it is preliminarily determined to use a double delta wing like the J-7E, and the air intake tract is ...... It's not conclusive yet, I wanted to refer to the mandibular air intake, but you just said that the feasibility is not high, so ...... Maybe think again. ”

Speaking of this, Sun Huizhong was a little embarrassed, after all, it sounded like the plane was borrowing from the model of the brother unit from head to toe......

Chang Haonan didn't care about this, what he was thinking about now was how to tell the other party the design plan in his mind.

It's not just a matter of asking 648 to simply copy an answer.

It is better to teach them to fish than to teach them to fish, and it is better to let them gain experience from it,

Besides, he only has a preliminary concept of Coach 9 now, and more detailed things have to be calculated to get it, so there is definitely no way to come up with a design plan tonight.

So Chang Haonan pondered the sentence:

"Actually, when I was designing the J-7F, I also considered another plan, but compared to the J-7, the changes were too big, and there was no way to directly upgrade from the old aircraft, so the design work was only carried out a little."

"If you have this will, when I finish the changes to match the J-7F with the new engine, I can work with you to improve the plan......"

This was a complete surprise for Sun Huizhong.

So before Chang Haonan finished speaking, he hurriedly agreed:

"Of course, I can apply with the firm and transfer some key members from the design team."

Sun Huizhong never thought about letting the other party go to the 648 Institute from the beginning.

On the one hand, anyone with a discerning eye can see that Chang Haonan came to 611 this time, and the J-7F is just by the way, and participating in the No. 10 project is probably a serious matter, and this new training aircraft is not an important project, and it is impossible to take up too much time and energy on it.

On the other hand, among the cities corresponding to the main designs of the aviation industry, Shengjing, Haojing and Rongcheng are definitely the best, and Bingcheng, Porcelain and Hongdu are also okay, but the geographical conditions of the city are really bad.

"Then let's do this first, and we'll talk when the matter on the 7th floor is over."

Chang Haonan said and nodded:

"In addition, the transferred person must at least master some of the basics of digital design, so that the efficiency will be much higher."

"No problem, I'll call tomorrow."

At this time, Sun Huizhong had already put excitement on his face:

"Thank you so much!"

……

The next day, Chang Haonan started work non-stop.

Random event, in the first half a year, the team led by Lu Yuying was not idle, and almost completed the design of the air intake duct and the parts other than the nose.

For him, he has actually gone through the design process of the J-7F, and now replacing the new engine is nothing more than taking the entire project team to go through the process again.

At the beginning, I was able to complete the preliminary design in three weeks with three full-time undergraduates, and now it is not a problem.

Moreover, the equipment level of the 611 computing center is not worse than that of Shengjing.

In short, with the cooperation of Chang Haonan and the project team, after half a month, the complete design plan of the J-7F was successfully taken out.

Compared with the original version of the design, in addition to narrowing and shortening the air intake to make the aircraft look more coordinated, it also refers to the experience of Yao Mengna when improving the J-8C, the cockpit windshield is changed to a circular arc, which greatly improves the pilot's vision, and a set of 140-liter capacity fuel tanks are added at the root of the vertical tail, which is better than nothing to improve the range......

As for the rest of the work, it is natural to send drawings to Factory 132 and let them build two prototypes.

A J-7F1 upgraded from the J-7B, and a newly manufactured J-7F2.

But now that the time has come to the end of January, no matter how efficient it is, the first flight will not be carried out until after the year.

As for the rest of the year, it is naturally left to Sun Huizhong and the 648 Institute.

They have been waiting in Rongcheng for half a month, and they have also participated in the improvement of the J-7F throughout the process, which can be regarded as accumulating some experience.

……

Computing center, inside the server room.

Sun Huizhong put a stack of materials on the table in front of him:

"Chang Gong, this is the main result of our current pre-research, and they are all here."

Several comrades from the 648 Institute gathered around the square table, looking at Chang Haonan who was concentrating on the drawings in front of them.

In the process of improving the J-7F, they have seen what work efficiency is.

So now for the latter, there is basically unlimited confidence.

After a while, Chang Haonan raised his head again:

"Since it is a trainer aircraft, it is not suitable for a single air inlet design."

He picked up a red and blue pencil, pulled out another piece of paper from the side, and drew a front view of an airplane on it:

"Whether it is the nose, belly or jaw, the single air intake must be arranged on the axis of the fuselage, encroaching on the altitude space, so it is difficult to arrange a rear cockpit with a height difference, so it is necessary to choose both sides of the air intake."

"Considering the structural characteristics of the J-7 itself, the rear fuselage should not be changed too much, so basically only the design of the subcostal air intake can be considered."

"In addition, it is the wing, and there is no problem with the choice of double delta wings, but the design of the J-7E is still too rough to look at now."

Chang Haonan put down the pencil and motioned for everyone to come to the front of the workstation:

"There are two plane shapes of the double delta wing: one is that the sweep angle of the front and rear wings is fixed, that is, the straight-sided double delta wing on the J-7E. On the other hand, the sweep angle of the front wing will gradually increase from a certain angle until it is 90 degrees parallel to the fuselage, in this case, the essence of the front wing is close to a super-large area of edge wings, and the shape of the rear wing will also change to a swept wing with a small angle, just like the F18 fighter. ”

He brought up the 3D model of the wing that he had made a few days ago while waiting for the results of the calculations, and then continued:

"From the perspective of stereotype, the distance between the front wing vortex and the rear wing vortex of the latter scheme will be larger, and under the larger angle of attack, the position of the vortex rupture point has been advanced to the middle of the front wing surface, and the separation flow formed after the rupture of the spiral vortex is affected by the increasing local sweep angle, and the vortex structure with a fairly compact structure is re-formed."

"This distribution of the split vortex structure allows the latter scheme to generate considerable vortex lift even after the rupture of the front wing vortex, in other words, the aircraft's stall angle of attack and lift coefficient will increase, and the maneuverability at large angles of attack, especially roll maneuverability, will be better."

"And at the cost of this option, the drag is much greater than in the first option, and it should be difficult for the maximum speed of the aircraft to exceed 1.5 times the speed of sound."

Speaking of which, Chang Haonan finally put together several preliminarily completed parts to form the shape of an airplane:

"However, for a training aircraft, as long as students can experience supersonic flight, the maximum speed is not the core performance, and it is definitely a profitable deal to exchange it for an overall improvement in the performance of large angles of attack."

"Of course, the more detailed numerical calculations have not yet begun, and it is not yet known how far the design scheme will be, so this is also our main task in the rest of the period."

But most of the people around him didn't hear these last two words.

Because everyone's attention has been drawn to the model of the plane on the screen-

Although it has not yet been designed in detail, it is very rough and uncoordinated.

But......

Two-ribbed air intakes, swept wings with large side strips, a cockpit with a large space and excellent visibility due to free space, and even a nose that can be crammed into a small radar......

If you say that from the J-7F, you can still see a little shadow of the original model.

Then the aircraft in front of them, even if the designers of the MiG Design Bureau are pulled over, they will definitely not recognize that this is an improved version of the MiG-21!

(End of chapter)