Lower to a height of 200 meters, turn on afterburner, and continue accelerating!

It's pretty much the same as just now, but this time, it hasn't sprinted to 900, it's just 700, and the residual oil warning light is on again.

Is it really out of gas this time?

Qin Feng can't fly anymore, if he flies again, what if he really runs out of fuel? This fighter plane is a valuable asset of the country, and it cannot be lost just like that.

"006, return immediately." After receiving this fault again, the command post in the rear commanded Qin Feng to return immediately.

So, Qin Feng piloted the fighter plane and returned to the airport.

Test flights are scientific, but today's incident is full of weirdness.

"There's still half a ton of fuel in the tank, and the residual oil warning light must be broken." The technician checked the status of the fighter and said to Qin Feng.

Qin Feng shook his head: "No, the warning light is not broken, when I came back, the warning light went out again, I flew twice today and found the law, this residual oil warning light will only appear when I drive the afterburner at low altitude for a long time." So, it's not an accident, it's definitely inevitable! ”

Now, Qin Feng has several vivid examples to tell everyone that in the test flight, any problem does not appear by chance, it is inevitable, and the reason must be found and carefully analyzed.

"Could it be that the circuit closed by accident caused by violent vibrations in ultra-low-altitude flight?" Someone said, "In this case, we need to replace the entire wiring harness." ”

There are a lot of wires inside the fighter, before the use of 1553B data bus, any instrument, there is a separate line, this indicator is naturally also, if there is a problem with the line, it is difficult to find out, you need to replace the entire wiring harness, that is a big project.

"Not necessarily." Qin Feng said: "If the circuit is closed due to vibration, then it will not be separated after closing, it should be closed all the time, or it is irregular flickering and flickering." ”

As the saying goes, it's the virtual connection of the circuit.

At this time, the ground staff has removed the indicator light from the dashboard, only to see that the base of the indicator light is intact, and the bulb is also intact, so it can be said that there is no problem with the indicator light.

Everyone circled around the J-8 fighter and looked back and forth a few times, but they didn't find a problem.

At this time, Mr. Gu had already come over.

There are a lot of test flight tasks every day, and Mr. Gu coordinates the situation of each fighter, and he has not come over until now, and after hearing Qin Feng's introduction, he also frowned.

"This is indeed a malfunction, but there is oil in our fighters, and from this point of view, it does not affect our flight." Mr. Gu said with a deep groan.

His meaning is naturally obvious, as long as the plane is not really out of fuel, then there is no need to be afraid, the fighter can still continue to fly, and it will not affect this test flight project.

Qin Feng shook his head: "Mr. Gu, your analysis is reasonable, we can continue to test flights, but this residual oil warning light tells us that the fuel is insufficient, if it is always on, our engine can't absorb oil, what should we do?" ”

Hearing Qin Feng's words, Mr. Gu's body suddenly shook, that's right!

The plane has oil, but the engine can't get it, so there will still be problems, Qin Feng is not afraid of flying, he has to consider all the situations clearly, after all, once there is a crash, it will have a great impact on the future of the fighter.

After Qin Feng said this, he looked at the side of the fighter, looked at the huge wing fuel tank of the fighter, and suddenly thought of something: "This fighter of ours has four fuel tanks, right?" ”

In the beginning, the aircraft only had a fuel tank inside the fuselage, but as the performance of the aircraft continued to improve, the more fuel was needed, the better, and the wing happened to be a good carrier, so the wing fuel tank appeared.

The exterior of the wing is made of aluminum alloy skin, and in the skeleton, the wing fuel tank is placed, so that the amount of fuel stored in the aircraft is greatly increased, and many large delta wing aircraft, and even passenger aircraft, almost rely on the wing to load fuel.

Afraid of catching fire when you get hit? For fighters, no matter where they are hit, the consequences are almost the same, and the fuel tanks have self-closing technology, and this kind of wing fuel tank began in World War II.

The wings on both sides have two fuel tanks, the fuselage has a main fuel tank, and an inverted fuel tank for inverted flight, which is four fuel tanks.

Mr. Gu nodded: "That's right, we have four fuel tanks." ”

"The switch of this residual fuel warning light is installed on the fuselage fuel tank, and according to our design, the fighter first uses the fuel from the wing fuel tank, and finally uses the fuel in the fuselage." In Qin Feng's mind, the idea began to become clearer and clearer: "But now, it should be the fuel in the plane that was used first, in this way, the fuel volume drops, and naturally the alarm will be called, and when I turn off the afterburner and return from level flight, the fuel in the wing fuel tank will slowly flow into the fuselage fuel tank, so the warning light will go out." ”

Qin Feng almost thought about it and said, after this reasoning was completed, Mr. Gu's eyes had slowly lit up: "That's right, your analysis is very reasonable, but why is the logic of using oil wrong?" ”

According to the logic of the fighter's fuel consumption, the fuel in the wing is used first.

If you don't find out this problem, you still can't solve this problem, the wing fuel tank is not fueled, once the fuselage fuel tank runs out of oil, then even if there is fuel inside the wing, the engine still has to be turned off, and it will be troublesome at that time.

Qin Feng also frowned: "Our J-7 fighter doesn't have this kind of problem." ”

J-8 is a double-hair large version of J-7, everyone knows this, now J-7 is no problem, what is going on with J-8?

Qin Feng was a little strange.

"Yes, we are completely designed according to the J-7, but it has been replaced with twin engines."

When he heard Mr. Gu say this, Qin Feng suddenly had a flash of inspiration in his mind: "Mr. Gu, is it because we have become a double engine, and we need a large amount of fuel supply when we open afterburner, but the fuel supply capacity of the wing fuel tank is insufficient, so we are forced to use the fuel tank of the fuselage?" ”

"Smack!" Mr. Gu slapped his thigh: "That's right, that's it!" ”

To say that this ability to analyze and judge, Qin Feng is simply a god, who would have thought that Qin Feng would actually analyze the cause of this failure, although Qin Feng came up with it, but there is no doubt that it is also very in line with the actual situation.

It was definitely the wisest decision that Qin Feng wanted to fly the J-8 at the beginning!