"There are still many problems with our J-8 oil engine." During the time of investigating the cause of the failure of the J-7, the test flight of the J-7 was suspended, and Qin Feng put forward some of his own views based on the flight experience of this time.

J-8 oil engine, there is a problem!

"Say it." The chief engineer of the aircraft, the engineer of the test flight, etc., all took out their notebooks and waited for Qin Feng's statement, they knew that what Qin Feng said next must be very important, and it was a problem they would face in the future.

"Our J-8 has completed the wet docking in the air, and it has also filled up my fighter with fuel, which shows that the problem of refueling in the air has been solved, but the existence of this tube has had a great impact on our flight."

If you want to talk about the most direct impact, of course, it is blocking the line of sight, but now that Qin Feng has brought it up, it is definitely not just as simple as blocking the line of sight, there must be more important problems.

"In the last test flight, because the situation was urgent, I turned on the afterburner and entered the supersonic flight, and after entering the supersonic speed, I found that the tube was in flight, rubbing and vibrating with the air, bringing a huge noise, when the speed reached Mach 1.5, this noise was already unbearable for the pilot."

This needs to be solved from the perspective of aerodynamics and other aspects, and now in short, although it solves the problem of refueling in the air, it is absolutely unacceptable if the aircraft cannot fly at supersonic speeds.

After all, the J-8 originally appeared as an interceptor in the territorial air defense, and once the situation was discovered, it had to be dispatched quickly, although it had all kinds of problems, but it was able to fly past Mach 2, and the fastest had flown to Mach 2.3, which is a point that many people are satisfied with.

Now, the high-speed capability of this aircraft has also been affected because of this tube!

If you only look at it from the windward area, although it has resistance, but the resistance is definitely not so large, when there is no tube, it can fly to 2.3, then with the tube, it is absolutely no problem to fly to Mach 2.

However, its noise is unbearable.

Although the engine of the aircraft is noisy, but after all, it is in the back, the impact on the pilot is not very large, when the pilot wears a helmet, it is acceptable, but it's different, the air refueling hose is different, it is installed in front of the pilot, once it makes noise, it just enters the cockpit, the pilot can't stand such a strong noise, it's too uncomfortable!

This is one of the most important problems, and if this problem is not solved, then this kind of air refueling pipe will still be a chicken rib.

"Yes, this is what we need to solve." said the chief engineer of the aircraft.

"There is one more serious problem than this." Qin Feng said: "In the case of high speed, this plane can not turn left, the last time I turned left, caused the right engine to stall, of course, in the situation at that time, it may be an accident, we have to fly further to be able to confirm, however, I personally think that it is related to this air refueling pipe, which seriously affects the air intake of the right engine." ”

J-8 has changed to the way of air intake on both sides, the air refueling pipe extends backwards, that is, the air intake of the engine, in peacetime, subsonic flight, there may be no problem, but, in the case of supersonic speed, this small refueling pipe may also produce supersonic shock waves, its vibration, it must be like this.

So, what effect does this shock wave have on the engine after it enters the air intake? Especially when steering, this effect is amplified and eventually leads to the shutdown of the engine?

This can be speculated, otherwise, why does the engine on the left not turn off, but the right one?

Compared with the first question, this problem is more serious, which is directly related to the flight safety of the aircraft, especially now, there has just been a serious accident, two comrades-in-arms left, how can this not let everyone be careful?

"We need to conduct rigorous wind tunnel experiments to verify the overall impact of the refueling tube on the aircraft with more accurate models, and at the same time, we need to continue flight experiments to determine that after completing in-flight refueling, our next stage goal is to explore the flight envelope of this aerial refueling fighter." The chief pilot of the test said.

The addition of an air refueling tube will definitely have an impact on the appearance, and now it is necessary to study it from both scientific and practical perspectives.

To study the shape of the aircraft, the wind tunnel is a must, the aircraft is moving, and what effect the air flow will produce on the aircraft can be carried out by calculation, but if you want to study it accurately, you still have to go through experiments, this is the wind tunnel, and only countries with wind tunnels have the ability to study aircraft.

Song Lao's final success in the No. 10 project is also inseparable from more than ten years of wind tunnel research, and the shape determined is quite mature.

After all, the inside of the wind tunnel is only a small-scale model, and the simulation may not be accurate enough for the air refueling pipe, and now, it is necessary to continue the test flight and march to supersound!

The air refueling tube, all the lengths add up, that is, half a meter, but only such a half-meter-long tube, there is a lot of knowledge in it, and it is only the first step of the long march to complete the air refueling, and then, it is not allowed to affect the maneuverability of the aircraft, which is also the next project to be studied.

The air refueling pipe of this oil receiving machine can be divided into two parts, the front is the probe, this is the international standard, when we introduce the refueling pod, we also introduced this kind of probe, after all, it needs to be used together, this does not need any modification, and the other part, it seems very simple, it is the straight rod part connected with the aircraft fuselage, and the knowledge is here.

Now, everyone is doing research here, and now, everyone has not figured out what is inside.

On the one hand, it is the sweep angle of the pole, that is, the tilt of the pole, the larger the sweep angle, the more inclined the pole, the smaller the resistance, but at the same time, in order to allow the aircraft to refuel in the air, the probe needs to leave part of the nose, if the sweep angle is too large, it also means that the tube will be longer, so that the stiffness of the tube is worse, it is easy to deform, now the main thing is to ensure the stiffness of the pole, so, the angle is very small, which causes a lot of resistance, especially in the case of supersonic.

This can be seen at a glance from the appearance, and in addition to this, there are two other factors.