What causes it?

As an excellent test pilot, not only to know that there is a fault, but also to understand the fault as much as possible, and prepare for troubleshooting, after Qin Feng heard this sound, the first step was to find the place where the sound occurred.

As long as it's not an engine, it's easy to say, after all, this aircraft uses turbojet-13, which is also a new engine, of course, the performance of this engine is still very stable, and there will be no problems, and now it has been determined that the problem is on the wing, so then, we have to see what the situation will be.

The first thing that comes to mind is speed, after all, this transition flight, Qin Fengfei's speed is not low, it has reached Mach 0.8, now, he loosened the throttle lever slightly, reduced the speed, and sure enough, with the decrease in speed, the flutter of the ailerons on both sides disappeared, and the sound stopped.

Then, Qin Feng tried to accelerate, and when it accelerated to around Mach 0.8, the ailerons began to tremble again, followed by the buzzing sound just now.

This is a problem with the ailerons, as the speed increases, the ailerons will begin to vibrate up and down under the influence of certain air currents or vibrations, and the frequency of the flutter will become higher and higher, and then the sound will come.

Fortunately, there is a sound, if there is no sound, it is directly fluttering, then it is not easy to find yourself, long-term flutter will cause metal fatigue and even breakage, once the ailerons are broken, it will still bring a threat to the flight.

Now, Qin Feng couldn't accelerate anymore, and at a speed of Mach 0.7, he flew slowly in the direction of the test flight institute, the range of this small plane had been doubled, so he didn't have to worry about fuel problems, and he didn't need to transfer flights.

The landmarks below became clearer and clearer, and finally, the runway of the test flight institute appeared in front of him, and he could even see the fighters on the test flight yard, including the J-7 he was testing, as well as the J-8D, and several large aircraft.

Along the familiar gliding line, Qin Feng piloted the fighter and began to land, the arrival of this plane attracted the attention of many people, because they all got the news, this aircraft has been improved this time, the performance has been reborn, and the close combat can even compete with the F-16!

They are on the ground, it is easy to see the difference in the shape of the wings, two different sweep angles, and there are obvious folds in the middle, this aircraft is the crystallization of the hard work and sweat of the people of Hanguo Aviation!

"Brother Feng, you're finally back!" When Qin Feng landed, he saw Tang Gang being the first to run up, standing under the ladder, and shouting at Qin Feng.

Qin Feng carried his helmet, walked down the ladder, hugged his old comrades-in-arms, and unconsciously, there was a deep affection between the test pilots.

"How's this plane?" Tang Gang asked.

"The performance is very good, you kid can also come up and apply for a test flight." Qin Feng said: "But when I first came, I found some small problems, and I have to report them to Professor Sha. ”

"Motivation wing, this is to touch the tiger's butt, it takes a lot of courage, but also needs to have a pre-accumulated technical reserves, any little bit of thoughtlessness, may bring problems in the test flight." When Qin Feng finished his report, one of the leaders on the scene immediately sighed.

I don't know how many roadblocks are waiting for them.

When Qin Feng came over, Professor Sha and the other designers had already arrived by train, Tu Lao didn't follow, he went to work on his super seven again, and now, Professor Sha looked at the model of the plane thoughtfully, and said: "We have blown through the wind tunnel, and when we blew the wind tunnel, we didn't find this phenomenon, and our tremor research is also in place." ”

The motor wing, the change is great, one of the difficulties is tremor, the Western University of Technology is also the most effortful, they have passed two rounds of review, but also passed the final fuselage resonance review, it is said, there will be no such low-level problems!

As soon as they were transferred to the test flight institute, they got in the way.

What to do?

"You're saying it's the ailerons that tremble, and then the humming sound, but we're sure that there weren't any of these problems in the wind tunnel, so where did this fault occur?" Professor Sha's thin face, his eyes were full of wisdom, and he suddenly thought of something: "So, we have to find the place of connection, I think, it may be in the aileron's action tube!" ”

There is no problem with the wind tunnel blowing, but in fact there is a problem when flying, not the aerodynamic layout, but the problem of the control system, this kind of aircraft compared with the previous fighter, the front and rear maneuvering flaps have been increased, and the atmospheric data computer is used to control at the same time, the control of the aileron is also different from before, the accuracy required is higher, and the processing of the aileron hydraulic action cylinder has put forward higher requirements, if there is a problem with the processing of this device, then fly into the sky, there will be a situation.

It's okay when the speed is low, but when the speed is high, the action tube may shake back and forth slightly under the drive of the ailerons, driving the buzz of the ailerons?

"Let's take it apart." Professor Sha said.

Finding the problem, finding the root of the problem, and then solving the problem, changing the wing, is to touch the tiger's ass, and we are now using the spirit of science to bravely touch the tiger's ass!

In the hangar of the test flight yard, the action barrel of the wing was disassembled, and when the hydraulic oil flowed out, it could be seen that there were some metal chips in it, and the reason was found!

"Professor Sha, you're amazing." Qin Feng also admired: "I think you can be a qualified aircraft designer." ”

Professor Sha was a halfway monk, he was originally engaged in research and theory in the university, but now he has become an expert in practice, Qin Feng admires it.

The feedback of these hydraulic fluids is very light, and his own operating lever does not feel shaking, otherwise it can be inferred that it is a hydraulic system problem, and now, the cause has been found, and the fault has been eliminated!

No matter how many problems there are, we must eliminate them and make this aircraft mature!

"Hey, Tang Gang, why are you still following me?" Now that he has found the problem, Qin Feng is also relieved, and at this moment, he found that Tang Gang was still by his side, like a gummy, don't you have anything else to do?

"You must have seen a lot when you went to the Soviet Union this time, and I want to hear from you." Tang Gang said.