Do you have to fly?

When the J-8 was designed, it was originally a high-altitude and high-speed fighter, as long as we don't mention this low-altitude and large speed, it is reasonable to say, especially, the task of test flight is so tense, if you don't test the flight subject, then you can save a lot of time.

"Director Wang, as long as the test flight is tested, there will be a certain risk, but the risk should be left in the trial stage, to yourself, not to the combat troops. In order to really play the role of trial and the flight safety after equipping the troops, we should test fly at low altitude and high table speed even if we take a little risk. As soon as Qin Feng finished speaking, Director Wang asked a question like this, so Qin Feng answered.

Of course, it is necessary to fly, all subjects must fly, and this danger cannot be left to the troops.

Needless to say, this kind of subject, how many years has the stall tailspin not flown off, and at Qin Feng's insistence, didn't the J-7's stall tailspin still fly?

"Yes, we can't leave this kind of subject to the troops, let's fly, we still have to determine the altitude of the test flight." Mr. Gu said.

How low is the low and low table speed?

The Phantom 2000 appeared in front of Qin Feng's eyes again, if it was the opponent's fighter to fly, ten meters would dare to fly, the performance of that kind of fighter was really strong.

Now, what about yourself?

Add a zero.

"A hundred meters, how?" Qin Feng asked.

Hearing Qin Feng's words, everyone's faces were ugly, one hundred meters, are you kidding? Who can fly that low?

"I'll fly." Qin Feng said: "Our low-altitude and large table speed is to test the structural performance of the fighter, and the higher the altitude, the greater the pressure on our aircraft, and the easier it is to test." ”

The lower the altitude, the denser the air, in the dense atmosphere, the aircraft is subjected to great resistance, the faster the flight, the greater the resistance, and the high-speed airflow will be like an increasingly sharp steel knife "sharpening" the aircraft. If the aircraft is not strong enough, the shell will be pried up and the wings will be flattened.

This is quite dangerous, in foreign countries, there have been cases of plane destruction and death in low-altitude and high-speed flight tests, unless it is the advanced zero-zero ejection seat of later generations, the pilot has no hope of being rescued at all.

Fly 80 meters, 50 meters, let's fly 100 meters, this is always okay, right?

"Two hundred meters." Mr. Gu spoke: "Our plane, the radio altimeter is not very accurate, below 200 meters, it cannot be accurately measured, let's be careful." ”

Mr. Gu doubled Qin Feng's proposal, two hundred meters, everyone will proceed according to this goal!

"Mr. Gu, I'll fly this project." Qin Feng said: "I'm still young, unlike other comrades, I have a family, a wife and children. ”

This subject is dangerous, Wang Yang and they are both married, if something happens, what will happen to the family?

Hearing Qin Feng say this, Wang Yang was not happy, and his face tightened: "Qin Feng, I don't like to hear this when you say this, what's wrong with us getting married?" Revolutionary work, we are still capable! ”

"Comrade Wang Yang, sit down, why are you still immature? At this time, what is the strength! Mr. Gu said: "At present, everyone is flying their own subjects, and they haven't finished flying yet, only after Comrade Qin Feng comes back, there are no new subjects, so it's okay to hand it over to Comrade Qin Feng to fly." ”

"Yes." Qin Feng was very happy: "Guarantee to complete the task!" ”

Accepting the task, Qin Feng didn't fly immediately, his first task was, of course, to choose a suitable airspace to fly.

Don't disturb the crowd, after all, at low altitudes, the sonic boom is quite terrifying, if it flies near the village, the window paper of the villagers in the village will be shattered, and the window glass will also be shattered.

There are really many villages around, Qin Feng studied the surrounding map for two days, and finally found a deserted Gobi Desert more than 500 kilometers away from the west side of the base, circled it with a pen, and called a car in the base, and went to the scene to see it in person, which can be regarded as determined.

The next day, the test flight at low altitude and high table speed finally began.

Qin Feng didn't wear that cumbersome flight helmet, now it was a low-altitude test, and he didn't need to fly at high altitude, so he finally didn't use the pressurized helmet, and put on his flight cap again, looking like he had returned to an era.

Somehow, Qin Feng remembered the Mirage 2000 again, the helmet worn by other pilots, it looked really good.

Stepping into the cockpit, skillfully preparing for the flight, connecting the various circuits, starting the engine, and soon, the fighter plane is taxiing and taking off.

This take-off reminded Qin Feng of the Phantom 2000, and it was cool enough for people to take off at such a large angle of attack.

Qin Feng didn't know that he had already been poisoned by the Phantom 2000, and if he didn't fly once, there was no cure for this poison.

"006 reports that the plane is normal and is heading to the intended airspace." Qin Feng shouted over the radio.

"The tower received, pay attention, the first test flight, the speed should be increased little by little."

"Understood."

The J-8 soon flew over the target, Qin Feng pushed the control stick, and the fighter slowly lowered the altitude, at this time, he had to be careful.

The altimeter was slowly lowering, and the afterglow of his eyes swept over the dashboard from time to time, where there were two altimeters.

That's right, it's so cumbersome, not just fighters, any aircraft will have two altimeters.

Without an altimeter, the pilot would have to estimate the distance of the aircraft from the ground with the naked eye, which is very inaccurate. And when the light is bad or the plane flies high, it is simply impossible to visually measure the altitude.

In this way, the aircraft must have an altimeter.

The first thing to be made was a barometric altimeter.

The higher the altitude, the lower the atmospheric pressure, according to the principle that the change in atmospheric pressure is related to the altitude, you can make an aircraft altimeter, which is actually a barometer, but the number displayed on the dial is the converted altitude, which is convenient for the pilot to use.

However, there is a drawback to this altimeter, which is that the accuracy is quite low. Look at it in a circle, it can point to more than 20,000 meters, a grid is a thousand meters, and the accuracy of one kilometer is almost estimated.

It doesn't matter if you fly at high altitude, but if you fly at ultra-low altitude and high gauge speed this time, it will definitely not work on it, so Qin Feng flew down and began to look at the barometric altimeter, and when the pointer of the altimeter was less than one thousand meters, he began to look at the radio altimeter on the other side.

The principle of this radio altimeter is also very simple, it works using the principle of reflection of radio waves. The transmitter emits radio waves to the ground through the transmitting antenna, and there is a time difference between the two radio waves. Multiply this data by the speed of light, divide by two, and that's the height.

This kind of measurement is quite accurate, the 100-meter level is more than enough, like the radio altimeter in the anti-ship missile, it is all in the meter level. (Essentially, it's not much different from a car's reversing radar.) ）