The problem has been thought of, but it is not easy to solve it.

According to Qin Feng, this belongs to the effect of tail turbulence at high speed, which hits the vertical tail, causing the rudder to swing at a small angle, bringing sudden changes in oil pressure and shuddering of the fuselage.

How to fix it? Is it necessary to modify the rear fuselage? It's a big project.

Moreover, in many cases, there is no calculation formula for this thing, and it must be known through experiments, and even the wind tunnel can't blow such a detailed change.

Modify the fuselage little by little, test flight little by little, I'm afraid it won't be able to be done in a year and a half.

Everyone was pondering bitterly, and Qin Feng remembered the last time he solved the problem of radar, and suddenly had an idea.

The 204 radar was subjected to strong clutter from the ground, which led to the failure of the radar, and no one could solve it at that time, and then I thought of the air intake cone of the MiG-21MF and the coating of the special conductive rubber, which was concocted in the same way and solved the problem.

Now, our J-8 has encountered this rudder flutter problem in the test flight, and if you want to solve this problem, you can also find an example for reference.

What examples?

MiG-23, of course!

The side has exchanged a MiG-23, this aircraft for the 601 Institute, the nose of the reference value is very high, because the J-8 must change the air intake on both sides in order to accommodate the large-caliber radar, just can be imitated, at the same time, in the tail, although the two aircraft are a single engine, a double engine, but the tail is a tall single vertical tail, which is also the only object that can be referenced.

Thinking of this, Qin Feng said: "Mr. Gu, I suggest that we refer to the 18-style vertical tail design, how about it?" ”

Suddenly mentioning the 18 type, few people know, in fact, the so-called 18 type, of course, is the MiG-23, after getting it back, in order to hide people's eyes, in the nose of the plane hurriedly painted with green paint with a 18 logo, the result became the 18 type.

Now, as soon as Qin Feng said this, Mr. Gu also nodded again and again: "Yes, we can find the differences in our hydraulic operating system from the 18 type." ”

At that time, the wreckage of the F-4 ghost was also obtained in China, but everyone never thought of copying it, because the American system and the Soviet system are different.

Now, the MiG-23 is of relatively large significance to domestic imitation.

"Qin Feng, Lao Wang, you come, let's go and find out." Mr. Gu said.

Qin Feng was stunned for a moment, looking at Mr. Gu like that, could it be that the MiG-23 is here?

MiG-21MF, the superiors have decided to let Chengdu come to surveying and mapping imitation, just parked in the 132 factory, disassembled the surveying and mapping, and the MiG-23 cannot be handed over to a unit.

There are many units waiting for it, the nose, the air intake, the variable sweep wing, the engine, are all for different research institutes, in this case, it is not suitable to put it in a certain unit, so it is simply placed in the test flight institute, and everyone goes to the test flight institute to study.

Don't look at Qin Feng, he has been here for a long time, but because of the different departments, this is the first time he has seen this fighter in China. Although it is near the hangar of the J-8, I didn't expect that after so long, I didn't even know it existed!

The nose of the plane, the wings on one side, have been removed, and when I walked in, there was still a group of people busy next to the plane, and one of the old men, who was disassembling the wing shaft, was carefully studying.

"Old Lu?" Qin Feng couldn't help but shout.

This old man is Lu Lao, who went with him when he went to Egypt last time, at that time, everyone was busy with work and didn't communicate much, but now when he sees Lu Lao, Qin Feng recognizes it at a glance.

"Qin Feng, you're here." Lu Lao was very excited, and said: "You said that the air intake on both sides is better than the nose air intake, and the resistance is small, everyone doesn't believe it, but as soon as you do a wind tunnel, you are really right, everyone admires it, how about the variable sweep wing?" ”

"Brother, aren't you embarrassed children?" Hearing Lu Lao ask, Tu Lao began to protect his shortcomings on the side.

Lu Lao is 7 years older than Tu Lao, it can be said that he is the elder brother of other chief teachers, and he is also the leader of the aviation industry.

Now, he is also the person in charge of Hongdu, a few years ago launched the design model of the Qiang-6, that is, it is intended to engage in variable swept wing, this time, the arrival of the MiG-23, of course, he is also quite excited, has already begun the mapping of the variable swept wing part of the MiG-23.

What Lu Lao values most is the variable sweep wing, but other people's views are different.

The variable swept wing used to be popular, but after it was used, the mainstream aspect of aviation in the Western world returned to the conventional layout, indicating that it was flawed.

Even Mr. Gu, after taking a closer look, found that the wings of the MiG-23 were connected by the stainless steel shaft, and he immediately lost interest.

Lu Lao asked Qin Feng, how should Qin Feng answer? When he first went to Egypt, Qin Feng seemed to have said that he was not optimistic.

It's just that everyone is busy with work and doesn't go into details.

"Old Lu, since you are taking the test, then I will briefly state my opinion, if there is something wrong, please bear with me." Qin Feng said.

"When it comes to variable sweep wings, the ideal is beautiful."

Qin Feng said this point of view, in fact, has been recognized by everyone: "When the fighter flies at high speed, the wing sweeps back to reduce the air resistance, which can increase the range and increase the maximum speed. ”

The reason why countless engineers have preferred the variable sweep wing in the first place is because of these advantages.

"However, the control of this variable sweep wing is complex." Qin Feng said: "Western electronic technology is advanced, such as the Tomcat fighter, which realizes the automatic control of the computer, and automatically changes the swept angle of the wing according to the state of the aircraft, while the Soviet Union's electronic technology is backward, so they use manual control, if I am a pilot, I don't want to be distracted in the fierce air battle to take care of the swept wing angle." ”

This is the case with the MiG-23, although it looks beautiful, but pilots will deliberately simplify it, it has three adjustment angles, it is deployed during takeoff, swept back when cruising, and placed in the middle during air combat.

For China, the MiG-23 is still a secret, but last time Qin Feng had already flown with Egyptian pilots in formation, he also felt the pulse of the MiG-23, and his wing operation was already clear.

"On the other hand, the variable swept wing needs to have a hinge and a wing box, which will increase the weight of the structure, improve the flight quality, and how to balance the increase in the weight of the fuselage, which is a big problem." Qin Feng continued.