Chapter 874 Design finalization is a new beginning
Autumn is passing and winter is coming.
In fact, the penultimate project in the entire national identification process was completed in November.
The reason why we pulled a large team of people and waited for nearly an extra month was to find the time window for the last test -
Special test for high cold.
This is a content that has just been added to the final test standards as China Airlines standards are gradually improved.
No model has ever been carried out before.
The good news is that the J-11WS verification aircraft uses the Su-27UBK airframe.
As a model designed and produced by the Soviet Union, the aircraft itself has experienced the severe cold test of the Arctic Circle.
So, there are only two turbofan 10 engines that need to be tested this time——
Under steady-state operating conditions, the internal temperature of the aircraft can reach thousands of degrees, and even the surface will be heated to a very hot level. Naturally, there is no need to consider low temperature issues.
But the transient process from stop to start does not work.
Especially many materials will undergo property changes under extremely cold conditions.
Typically, almost all metals are cold brittle, with increased strength but decreased toughness.
Whether an aero engine with a complex structure and huge changes in operating conditions can withstand such abnormal changes is what the special high-cold test will determine.
In addition, this test will also pave the way for the subsequent introduction of similar tests into national standards related to the entire machine.
……
Hailaer, Dongshan Airport, Meng Province.
Chang Haonan was wearing the thickest cotton-padded coat he had ever worn in his life, and two layers of scarves, but he was still shivering in the cold wind.
He took his left hand out of his mittens, wiped the white frost on his eyelashes formed by the breath, and then looked at the time.
1:40 am.
Just such an action, which lasted less than 5 seconds, already made Chang Haonan feel the stinging pain like a knife on his exposed skin.
Hai Yide, the chief engineer next to him, went to school in Bingcheng for nearly 10 years when he was young, but after all, despite his age, his body is a little unable to bear it.
Fortunately, there is a station in Hailar where aviation units are not permanently stationed. From there, some ground crews were temporarily supported, which allowed the entire testing process to run normally.
In fact, military aircraft testing was originally more suitable for military airports, but the local area did not have the hardware conditions to maintain third-generation fighter jets, so this time there was an Il-76 carrying equipment following the J-11WS.
The 2,600-meter runway of Dongshan Airport is obviously more suitable for serving such big guys.
"Mr. Chang, the temperature has now dropped to minus 41.5°C, which has reached the test standard!"
Just when Chang Haonan was trying to figure out whether to let Haiyide go inside the terminal to warm him up While talking, a man suddenly strode up to Chang Haonan and reported loudly.
All comrades in the Air Force wore uniformly issued cold masks, so Chang Haonan recognized the person's identity after looking at the other person's military rank.
Wei Qiang, the deputy webmaster of the site who led the team to assist in the test.
Chang Haonan took a deep breath, and a long wisp of white mist emerged from his mouth and nose.
Even in the cold pole of China, waiting for a stable -40℃ does not happen every day.
For this reason, they have been staying here for nearly a week.
“Let’s start!”
“Yes!”
Wei Qiang stood upright and raised his hand to salute Chang Haonan.
The subject content involved in the special test is actually very few, only a few related to engine cold start.
As Chang Haonan's order was issued, the vehicles and personnel who had been waiting for several days around the fighter suddenly became busy.
In fact, if auxiliary facilities such as power supply, gas source, and oil are prepared in advance, the time spent in the test process can be further reduced.
But after all, this is the first time that the whole of China has been tested under similar conditions, so every link and every detail must be tested perfectly.
If it is later confirmed that low temperature does not pose a risk to certain steps, then consider subtraction.
“I always feel like every time I do a test with you, I can see some new tricks that I haven’t seen before.”
Haiyide next to him stamped his feet violently, and his voice sounded They were all trembling.
Chang Haonan wanted to deny it, but after thinking about it carefully, it seemed that this was really the case.
Since the first revision of the national military standard on the Turbojet 14, every project he has participated in has basically updated the relevant industry standards.
So I had to come up with a bunch of quotations from scriptures:
“There is no road in this world, but when there are more people walking, it becomes a road...”
This is really what Lu Xun said...
On the other side, although the severe cold caused some deformation of the movements, the ground crew and technicians still connected the pipelines of several auxiliary vehicles to the aircraft within the time specified in the outline.
With a sharp buzzing sound, the taxi lights, navigation lights, wing lights and red anti-collision lights located on both sides of the aircraft's landing gear and wings were illuminated at the same time.
The pilot's voice in the cockpit came from the radio:
"The equipment is powered on successfully and the engine self-checking system starts to work!"
Although the fault fusion diagnosis system developed by Chang Haonan was not required The sensor is too complex so it has not been put on the aircraft yet, but the Turbofan 10 is an engine model with FADEC after all, so it is no problem to complete a usable status self-check.
About half a minute later, the radio rang again:
"Self-test successful!"
Although passing the self-test does not 100% mean that the engine status is completely normal, it at least indicates that the relevant electronic control unit is in a usable state.
And this is also prone to low temperature failure
Beside Chang Haonan, someone excitedly waved his fist in the air.
It’s just that because the clothes were too thick, I didn’t show the usual excitement at all.
On the contrary, it seems a bit funny...
However, after being disturbed in this way, the atmosphere at the scene, which had just been so serious that it was almost frozen, became slightly more relaxed.
Of course, the national certification test is definitely not a success just because the pilot said it was a success.
Technicians are also using instruments to simultaneously monitor the status of the aircraft. Formal certification standards need to be more stringent and detailed.
So, it was not until ten minutes later that they gave the same result.
Passed smoothly!
The next step is the second test session.
Under the joint electric drive, the fuel and oil system supplying the engine is also activated.
Under low temperature, the flow characteristics of oil and the working status of pipelines, pumps and valves will be affected.
Especially the two low-pressure pumps and the low-pressure shut-off valve set before the fuel heater are the top priority of the low-temperature test.
Perhaps it was Chang Haonan's misunderstanding, but the time interval between pilots giving results was much longer this time.
But in the end, everything was as he expected:
“The oil temperature, oil pressure, and fuel flow are normal, and the throttle status response is normal!”
From the timing results Look, although the response is slower than normal, it is still within the allowable range of the standard -
The ground startup process does not need to be very sensitive, as long as the pilot's action intention can be faithfully executed. .
...
As time went by, the preparations were completed one after another.
Finally, the final moment has come.
Before the sun rises, the darkest and coldest time of the day.
The temperature has dropped to -43.2℃.
God is good.
If the temperature suddenly rises during the trip, you may have to wait for another time window.
Chang Haonan took a step forward and picked up the wireless phone.
“Start the engine!”
Almost everyone clenched their fists at this moment.
As long as this step is completed, the turbofan 10 will officially complete the design and finalization appraisal.
Invisible to everyone, the fuel nozzle began to inject atomized aviation kerosene into the combustion chamber. The fuel quickly and evenly filled the entire space, along with the air sent into the combustion chamber through the compressor. Mix thoroughly.
Almost at the same time, the electric spark generated by the electric ignition device ignited it all.
"Bang——"
A crisp and short explosion sounded.
Immediately afterwards, there was a slightly sharp roar...
The duration of the whole process was only about one or two seconds, but under the combined effect of tension and low temperature, it was as long as a century or two
Subsequently, the engine speed climbed sharply, then fluctuated slightly for a few times, and finally stabilized near the idle speed.
After the engine enters working condition, the temperature of the entire system will also rise to the normal design level.
For the special alpine experiments, it is no longer a part that requires special attention.
A little further away, the leader of the appraisal team of the General Armament Department took off his headphones, stood up and looked at Chang Haonan and his party:
"The engine started successfully!"
At this moment, even if The severe cold of minus 40 degrees Celsius could no longer dampen the enthusiasm of the test participants.
Although there are still some purely administrative processes to go before the strict "design finalization", at this point, it is completely ready to open the champagne.
Some people even took off their cotton hats and threw them into the air in ecstasy.
"Successful, successful..."
Haiyide didn't make any exaggerated movements. He just clenched his fists tightly, squatted down, and kept mumbling in his mouth.
Hearing his voice, Chang Haonan finally breathed a sigh of relief.
A warm current emerged from the body, and it even seemed to dispel the severe cold all over the body.
After a while, several deputy chief engineers, including Liu Yongquan and Yin Yongze, came closer from the surroundings and hugged or shook hands with Chang Haonan and Hai Yide respectively.
Chang Haonan couldn't even tell whether what was hanging around some people's eyes was frost from breath or frozen tears...
"Mr. Chang, it's done!"
Following this Members of the project team and the leader of the appraisal team also came over and held their hands tightly with Chang Haonan:
“The Turbofan 10 is the first aviation company in China to independently complete the entire process from project establishment to finalization. Engine model, I am honored to have the opportunity to participate in it personally.”
“It’s not time to relax yet.”
Chang Haonan is naturally filled with joy, but as the anchor of the entire project team, he knows that he cannot be too impatient during such a time of joy:
“The design finalization is the end of the previous stage. It is also the beginning of a new stage.”
“The subsequent tasks of ramping up production capacity and finalizing production still require close cooperation between us!”
The leader of the appraisal team is from the Air Force. He was so happy that he grinned from ear to ear:
“One item at a time, one item at a time... It has taken three and a half years to get to this point, which is an absolute miracle...”< br>
Production finalization and design finalization are two tasks that sound similar but are completely different in practice.
Some equipment may have been manufactured for a long time, and may even be almost retired, and the production and finalization process has not yet been completed.
In the end, the entire life cycle was implemented as a "small batch trial production" to achieve large-scale equipment.
So, he knew that this matter could not be rushed.
Chang Haonan just nodded and did not reply.
But in fact, he already has some new ideas on how to improve the production efficiency of air film holes.
Next, we only need to wait until the equipment in the Torch Laboratory is in place before verification...
(End of Chapter)