Chapter 1400: Ground Tests in Advance

half a month later.

Factory 132, western suburbs of Chengdu.

The No. 1 assembly workshop is still brightly lit in the night, and two black-gray painted J-20 verification aircraft lie quietly under the dome with intertwined argon gas pipes.

Yang Wei took off his oily gloves and glanced at the newly installed WS-2003G tail nozzle at the root of the wing of No. 10. The slender gray shell exuded the unique cold and hard texture of metal in the light, forming a sharp contrast with the shorter and bright silver WS-2001A tail nozzle on No. 10 next to it.

The subtle differences in appearance are naturally just superficial. The core reason for replacing the new tail nozzle is that the old model may not be able to withstand the higher temperature tail flame under the afterburner state, and adapt to the plasma generating device that has never existed before.

As for the change in length, it is simply to optimize the flow characteristics of the tail flame.

"Lao Liu, remember to check the setting parameters of the fan leading edge vibration probe again."

While directing Liu Yongquan, who was not far away, to carry out the next step, he picked up the ballpoint pen at hand and ticked the second-to-last item on the form:

"Although we won't be testing aerodynamics this time, the ground resonance frequency must be strictly aligned, so that we can save a lot of trouble before the test flight later."

Liu Yongquan was squatting cautiously on an operating stand that extended above the aircraft. Several black signal lines extended from the back of the operating terminal in front of him, connecting to an opening on the top of the aircraft:

"The average difference between the amplitude parameter and the input standard signal is 0.33 microns, and the maximum difference is 0.45 microns. Both are within the allowable range. I will start measuring the frequency data immediately..."

The voice was faintly trembling.

As an aeroengine engineer, he rarely needs to perform such high-altitude work.

The surrounding railings and the safety rope around the waist can provide security, but they cannot provide a sense of security.

Moreover, compared to getting injured in the fall, he was more worried about hitting the plane and causing damage to the two more fragile composite materials between the No. 17 and No. 18 bulkheads.

Although it seems that ground crew can step on the aircraft without restraint on weekdays, their movable area is actually strictly restricted.

The skin materials in some specific areas are specialized in tensile strength, but may not have strong shear resistance. If you step on them rashly, you may cause damage.

At the same time, the truss crane on the top of the workshop moved slowly and embedded the last set of fiber optic sensors into the skin interlayer on the back of Machine 2003.

In the cold wind of winter nights, dozens of technicians shuttled between fighter planes and equipment, meshing every process like precision gears, and compressed the final assembly of the No. 2003 aircraft, which would have taken more than a month according to the plan, into fifteen days and nights.

Originally, since No. 2003 was not in a hurry for its maiden flight, the production task was relatively relaxed.

But considering Liu Yongquan's more urgent needs, Yang Wei decided to provide some help within his ability.

However, for new aviation equipment, especially the fourth-generation fighter jets, which are the main aviation equipment that are given special attention by the decision-makers, the first flight node is a big event. Even the chief designer does not have much say in such matters.

Therefore, the latter decided to advance part of the ground test process of No. 2003 to shorten the first flight interval between the two verification aircraft.

Fortunately, the overall structure of No. 2003 is not much different from that of No. 2001, and the intensity of basic work in the previous period was not high, so even if the construction period is shortened by half, it can still be handled with ease.

"All right!"

Fifteen minutes later, Liu Yongquan finally climbed back down the ladder to the ground, took off the safety rope and breathed a sigh of relief:

"All sensors related to the engine, including backup equipment, have been tested to ensure stable and accurate data output!"

Perhaps to hide the embarrassment of his weak legs, he deliberately raised his voice when he said this.

Yang Wei nodded, without exposing the other party's little thoughts, but picked up the pen and ticked the last item on the form, then handed the folder and pen to the other party:

"Check it out. If there are no problems, please sign under my name. Then you can prepare to move to the testing station in the next time window."

Hearing these words, a gleam of light suddenly flashed in Liu Yongquan's slightly tired eyes.

According to regulations, the transfer of aircraft between different workshops can only be carried out during specific time windows at night.

Today's overnight transfer means that testing can begin during the day tomorrow.

But a trace of worry soon emerged, and he looked at the No. 2001 aircraft in the distance that had completed the indoor testing process:

"Old Yang, I saw that when the No. 01 aircraft was tested a few days ago, it has always maintained the temporary configuration of the first flight state. It has a lot more parts than the No. 03 aircraft. Will it affect the results of the control variables?"

Yang Wei was checking the personnel schedule for the transfer at this moment, and shook his head immediately upon hearing this:

"The extra sensors will only affect the stealth performance and some aerodynamic performance. As long as these two aspects are not affected, other tests can still be carried out as usual... And the landing gear will be fixed with electromagnetic locks throughout the test. Even if there are slight differences in the center of gravity or structure, they can be compensated to a certain extent according to the parameters of the electromagnetic locks."

In fact, Liu Yongquan also knew that these processes should be familiar to his peers in the aviation industry.

But after all, this is my first time following the installation test, so it is inevitable that I pay more attention to these details...

……

When the first ray of morning light penetrated the tall windows of the factory building, Yang Wei finally announced the start of the test.

The on-site commander immediately began to issue specific operational orders.

"Starter test, dual cold start."

"Oil system testing, fuel and oil pump starting."

"Prepare to ignite, maintain slow speed first"

As the operator in front of the console gently pushed the throttle, the unique low hum of the turbofan 10G resonated in the confined space.

In the backstage data monitoring room further away, Liu Yongquan stared at the flow field temperature model given on the screen next to him.

The engine at idle speed does not have a tail flame visible to the naked eye, but this does not mean that the high-temperature combustion gas pouring out from behind the tail nozzle does not exist.

With the help of infrared imaging sensors and pressure field distribution sensors, the flow field conditions under this condition can still be restored basically accurately.

Of course, as a well-tested model, it is unlikely that there will be any problems at low revs.

So the atmosphere at this time was still relatively relaxed.

However, a relatively young aeroengine engineer suddenly asked:

"Why is the temperature distribution shown by the infrared imaging signal relatively uniform, but the signal at 90° in the annular distribution diagram of the radiation signal is the strongest? Could it be..."

He originally thought that there might be a problem with the engine assembly, causing the high-temperature combustion gas to overflow from the side.

But such an outrageous speculation was denied by him in the next second. After all, the content shown on the infrared imaging image seemed to be normal.

This sudden shout startled everyone present, but they immediately relaxed after hearing the question.

Without waiting for Yang Wei to speak, Liu Yongquan took the lead and patted the other party on the shoulder, signaling him to calm down:

"The infrared test of the whole aircraft is different from our aircraft engine test. The annular distribution diagram measures the radiation flux, while the radiation in all directions is relatively uniform when the engine is just started. The final result is naturally that the side with the largest surface area projection has the highest value... In fact, if it is a 540° stereo test, the signal data on the top surface will be even stronger."

As if to confirm his statement, due to the gradual accumulation of heat inside the engine, the signal strength in the 180° direction, that is, the tail, gradually increased, pulling the entire schematic diagram into a shape similar to half a shield.

The small commotion caused by the young people soon subsided, but everyone still needed to wait for a while for the idle data to stabilize.

At this time, Yang Wei seemed to suddenly remember something and looked at Liu Yongquan next to him:

"Old Liu, I don't know if you remember that when the J-10 was first tested on the ground, the debris inside the fuselage almost damaged the engine..."

The latter recalled briefly:

"The one that triggered a major quality rectification campaign across the Aviation Industry Corporation of China?"

At that time, the two sides had not yet separated, and Liu Yongquan and his friends were really troubled for a long time, so they were deeply impressed.

Yang Wei nodded.

"I heard that it was Mr. Chang who discovered the problem in the beginning?"

Liu Yongquan was not at the scene at that time, but Lin Hui, the engineer who volunteered to go into the air intake duct to check the engine condition, is now one of his important assistants, so he has heard many details from the latter.

Yang Wei was a little surprised when his words were interrupted, but he quickly changed his words:

"Yes, and the problem was finally solved by Mr. Chang designing a special cleaning mandrel on site, which cleaned the dead area inside a one-way flap."

This really touched upon Liu Yongquan's blind spot in knowledge:

"Is there still this?"

"That's... That's why I always thought that after the separation, Academician Chang would stay with us in the aviation industry."

"..."

At this moment, the on-site commander's new voice sounded in the communication system:

"Increase the speed..."

As the engine operating conditions gradually approached military thrust, light blue air spiraled out from the serrated tail nozzle, outlining a perfect Mach loop in the air duct behind the aircraft.