Chapter 1400 Early ground test


    Half a month later.


    Factory 132, western suburbs of Chengdu.


    The No. 1 assembly workshop in the night is still brightly lit, and two black and gray-painted J-20 verification aircraft are lying quietly under the dome of the interweaving argon pipeline.


    Yang Wei took off his oily gloves and glanced at the newly installed turbofan 10G tail nozzle at the wing root of No. 2003. The slender gray shell was filled with the unique metal cold and hard texture in the light, which was in sharp contrast to the turbofan 10A, which was shorter in length and bright silver in the upper tail nozzle at No. 2001 next to him.


    The subtle differences in appearance are naturally just appearances. 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 state of overburdening, and adapting to plasma generators that have never been seen before.


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


    "Old Liu, remember to check the settings parameters of the front edge vibration probe of the fan."


    While directing Liu Yongquan not far away to carry out the next step, he picked up the ballpoint pen at hand and made a hook to the penultimate item listed on the form:


    "Although we did not test aerodynamics this time, the ground resonance frequency must be strictly aligned, so that we can do a lot of things before the interview flight."


    At this time, Liu Yongquan was squatting carefully on an operating frame extending above the aircraft. Several black signal lines extended from behind the operating terminal in front of him, connecting to an opening above the back of the aircraft:


    "The average difference between the amplitude parameters and the standard signal input is 0.33 micron, and the maximum difference is 0.45 micron, both within the allowable range. I will start measuring the frequency data immediately..."


    The voice was vaguely trembling.


    As an aerospace engineer, he rarely needs to perform such high-altitude operations.


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


    Moreover, compared to being injured after falling down, what he was more worried about is that after hitting the plane, the two relatively fragile composite materials between the No. 17 and No. 18 will be damaged.


    Although the ground staff seem to be able to step on the plane without restraint on the surface, their movable areas are actually strictly restricted.


    Skin materials in some specific parts 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, embedding the last set of fiber optic sensors into the skin mezzanine on the back of the No. 2003 machine.


    In the cold wind of winter night, dozens of technicians shuttled between the fighter jets and equipment, tying each process like precision gears, and assembled the No. 2003 machine as planned, it would take more than a month to compress it into fifteen days and nights.


    Originally, since the first flight was not in a hurry to fly in 2003, the production task was relatively relaxed.


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


    However, the first flight node of new aviation equipment, especially the fourth-generation fighter jets, is a major event, and even the chief designer does not have much say in this matter.


    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 No. 2001, and the basic work intensity in the previous period was not high, so even if the construction period was shortened by half, it was still easy to do so.


    "alright!"


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


    "All engine-related sensors, including backup equipment, have completed testing to ensure stable and accurate data output!"


    Perhaps to cover up his embarrassment of being weak, he deliberately raised the volume a lot when he said this.


    Yang Wei nodded, not exposing the other party''s little thoughts, but picked up the pen and ticked it behind the last item of the form, and handed the folder and the pen to the other party:


    "You check it. If there is no problem, just sign the letter under my name, and then you can prepare to transfer to the test station in the next time window."


    Hearing this sentence, a light flashed in Liu Yongquan''s slightly tired eyes.


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


    Transferring overnight today means testing will start tomorrow during the day.


    But then another worry emerged, looking at the No. 2001 machine a little further away that had completed the indoor testing process:


    "Old Yang, I saw that when the No. 01 aircraft was tested a few days ago, it maintained its temporary configuration in its first flight state. It was much more fragmented than the No. 03 aircraft, and it would not affect the results of the control variables, right?"


    Yang Wei is checking the arrangement form for the personnel responsible for the transfer. He immediately shook his head when he heard this:


    "The extra sensors will only affect stealth performance and some aerodynamic performance. As long as these two aspects are not involved, other tests can still be carried out as usual... and the landing gear will be fixed with an electromagnetic lock throughout the test. Even if there are slight differences in the center of gravity or structure, certain compensation can be made based on the parameters of the electromagnetic lock."


    In fact, Liu Yongquan also knows that these processes should be considered familiar to colleagues in the aviation industry. But after all, it was the first time that the installation test was followed throughout the whole process, so it was inevitable that you would pay more attention to these details...


    …


    When the first ray of morning light penetrated the high windows of the factory, Yang Wei finally announced the launch of the test.


    The on-site commander immediately began to issue specific operation commands.


    "Starting test, double chilling."


    "The oil circuit system tests, the fuel oil pump starts."


    "Prepare to ignite the ignition and maintain the slow state first"


    As the operator in front of the console gently pushes the throttle valve, the unique low hum of the turbofan 10G oscillates 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 state does not show a tail flame that is visible to the naked eye, but this does not mean that the high-temperature gas gushing out from behind the tail nozzle does not exist.


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


    Of course, as a well-tested model, it is almost impossible to have any problems at low speeds.


    So the atmosphere at the scene was relatively relaxed at this time.


    However, a relatively young aerospace engineer suddenly asked:


    "Why is the temperature distribution displayed by infrared imaging signals relatively uniform, but the 90° direction signal has the strongest signal on the ring distribution diagram of the radiation signal? Will it be..."


    He originally wanted to say whether it was because of the engine assembly problem that caused high-temperature gas to overflow from the side.


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


    This sudden shout made everyone present shudder, but after hearing the question, he immediately relaxed.


    Before Yang Wei could speak, Liu Yongquan took the lead in patting the other party''s shoulder and signaling him to be calm:


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


    As if it was confirming his statement, due to the gradual accumulation of heat inside the engine, the signal intensity in the 180° direction, that is, the positive tail gradually increased, pulling the entire schematic into a shape similar to a half-face shield.


    The small commotion caused by the young people quickly subsided, but everyone still had to wait for a while to let the idle data go into stability.


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


    "Old Liu, I wonder if you have any impression that when the J-10 was conducting ground startup test for the first time, the debris inside the body almost broke the engine..."


    The latter recalled a little:


    "That time that caused major quality rectification within the entire aviation industry company?"


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


    Yang Wei nodded.


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


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


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


    "Yes, and finally solving the problem, Mr. Chang designed a special cleaning mandrel on site to clean the dead zone inside a one-way trap."


    Now, it really touched Liu Yongquan''s knowledge blind spot:


    "And there is this?"


    "That''s...so I always thought that Academician Chang would stay with our aviation side after the separation."


    “…”


    At this moment, a new voice from the on-site commander sounded from the communication system:


    “Increase the speed…”


    As the engine conditions gradually approached the military thrust, light blue airflow spiraled out from the serrated tail nozzle, and the perfect Mach ring was outlined in the air duct behind the aircraft.


    (End of this chapter)