"Today, we're running a mid-speed run." When I came to the track again, it was already the third day, and yesterday I sorted out all the data for the low-speed run, and everything was difficult at the beginning, but it was already smooth at the beginning, so it will be more and more smooth in the future!

"When you run at a medium speed, you have to aim at the track, then release the brakes, do nothing, and accelerate to 100."

"Don't worry, Old Zhou, this medium-speed run, we will definitely be able to pass it at one time." Qin Feng said.

You have to test all kinds of data when you run at low speeds, and if you run at medium speeds, you just let go of your hand, let the plane slide to 100, and then brake again, and it's over.

Like last time, the plane was started when it was in the parking area, and it taxied to the end of the runway at a low speed, aiming at the center line of the runway, Qin Feng took a deep breath and shouted on the radio: "I have aimed at the runway, and I request to start the test flight." ”

"Yes." A voice came from the radio, Qin Feng released the brake, pushed the throttle to 30 percent, and the fighter slid on the runway.

In the performance of the car, there is a performance test from zero acceleration to a hundred, which is very similar to the current one, in order to test, the power of the engine is not fully opened, otherwise, any sports car can not compare with the fighter, after all, the engine of the fighter can be much more powerful than the piston engine.

Wait, what's going on?

"Brake!" There was a sound in the earphones, in fact, before the sound came, Qin Feng had already quickly pushed the throttle stick to the position of the slow car, and then stepped on the rudder surfaces on both sides.

From him, you can see the nose, the nose was firmly aimed at the center line of the runway before the exercise, but now, the low speed has only slid out of a few tens of meters, the speed has increased to seventy, and the nose has deviated from the center line of the runway and deviated to the left!

As the speed continues to increase, the nose of the fuselage is even more off, and the entire fuselage has left the runway centerline!

Medium-speed sliding, verification of a project, to see if the plane can slide in a straight line, yes, just like just learning a driver's license after driving in a straight line, the plane just after it is built, it also needs to be tested, that is, without any control, only under the thrust of the engine to see if the plane can slide forward to run in a straight line.

If you can run, it means that the design is fine, if you can't run a straight line, then the problem is big!

There are many reasons for this situation, such as the problem of the aerodynamic layout design of the aircraft, the left and right asymmetry, so that after acceleration, the aircraft can not run in a straight line, or it may be that there is a problem with the placement of the landing gear on one side, the position is not suitable, or the brakes are stuck, which will cause the aircraft to not slide in a straight line.

I thought that this medium-speed coast was simpler than low-speed, accelerating, decelerating, braking, and ending, but who would have thought that it would deviate!

After Qin Feng braked, the naked eye could see that the fuselage had left the center line of the runway three or four meters, not only did it deviate, but it was also quite serious!

The faces of the people present were all the same ugly, and sure enough, there was a roadblock.

What caused the plane to deviate?

Is it a pneumatic layout? If from the perspective of aerodynamic layout, if the two sides are inconsistent, it is easy to lead to deviation, but this deviation, it almost means that the design of the aircraft has failed, and the aerodynamic layout of the aircraft is asymmetrical, so is the aircraft still successful?

Song Lao's face was full of seriousness, and at this time, the plane stopped at the place where it had deviated, standing there diagonally, and everyone had ugly faces.

"It shouldn't be a pneumatic problem." Qin Feng came down from above and said: "We have blown through the wind tunnel so many times, there is no problem in terms of aerodynamics, I suggest, we should analyze it from the simplest place, for example, is it the deviation caused by the different braking strength on both sides?" ”

If it's the simplest, it's a brake problem, one side is tight, the other side is loose, the speed is up, and it will naturally deviate.

"Yes, analyze the data!" Song Lao said: "Push the equipment over!" ”

When Qin Feng heard this, he immediately thought of something, that's right, he was the chief designer, and his familiarity with this aircraft far exceeded his own, he could only guess that it might be a problem with the brakes, and Song Lao had already guessed that it was probably a problem with the anti-skid system of the brakes!

In order to ensure the smooth landing of the aircraft, the braking system of the aircraft also has special anti-skid measures, this device, somewhat similar to the ABS system of the car, it is also one of the advanced subsystems developed in China, if there is a problem with this system, it may lead to additional braking force.

"Old Song, if analyzing the data is still not good, then we can release the brakes and try again." Qin Feng said to Song Lao.

As long as you release the brakes and try again, if you don't deviate this time, it means that it is a brake problem, and everything else is ruled out at once.

However, if the brakes are released, how can the aircraft be stopped after the test is over? If you can't stop, you'll get off the runway!

"How are you going to stop the plane?" Song Lao asked.

"Airbrake." Qin Feng said: "Today's weather is very good, if there is a crosswind at the airport, it will not be easy for us to experiment again." ”

If there is a crosswind on the runway, it will naturally blow the plane to the side, and it is good to say that on the aircraft carrier, on the aircraft carrier, the carrier-based aircraft that glides and takes off may be blown into the sea because the crosswind is too strong.

In order to determine the location of the fault as soon as possible, you can release the brake and try it once, and then, rely on the speed brake to stop!

In order to slow down the aircraft, all kinds of fighters are equipped with speed brakes, such as F-15 and Su-27, are equipped with a huge speed brake like a sail on the back of the aircraft, and the J-10 is installed below, specifically, at the rear of the belly, there is a "four-petal" type speed brake. Although there is no brake, the runway is very long, only accelerating to seventy or eighty, the runway is only used for one-tenth, and the rear is used to slow down, which is no problem.

"Plus a parachute." Song Lao said: "Let's wait until we check all the data, and then try again!" ”

The anti-skid brake system is newly developed by its own side, if it fails, it is likely that there is a problem in this regard, in order to be able to determine the cause of the failure as soon as possible, Song Lao also decided to agree with Qin Feng's plan.

Coupled with a parachute, it should be safer!