Chapter 625 Test Preparations for the 375th Generation Aviation Engine

When Chang Haonan met Haiyide in the test workshop, the latter was holding a walkie-talkie and sternly directing the on-site technicians to transfer the B0101 prototype from the dedicated engine bracket to the spreader on the high-altitude platform.

Compared with the aviation control system in the past, which was mainly hydraulic and mechanical, supplemented by some analog signals, the turbofan 10 with full authority digital control capability looks much simpler in appearance.

Because a large number of hydraulic and pneumatic pipelines originally used for control and action functions were canceled and turned into several engine control units and cables distributed around the aircraft.

In addition to reducing the reliability problems caused by these complex mechanical structures, it can also reduce a lot of weight and cost of the engine.

Combined with the simpler 2-stage fan + 7-stage high-pressure compressor structure compared to the third-generation aircraft engine, the national military standard weight of this engine was finally reduced to an astonishing 1560kg.

For comparison, the dead weight of two typical third-generation engines, F110 and AL31F, calculated according to national military standards, is in the range of 1750-1800kg.

Of course, 1560kg is still not the end point.

The reason why Tube Turbofan 10 is called the 3.75-generation engine is because although its structure has almost infinitely moved closer to the fourth-generation engine, most of the materials and production processes are still at the level of the third-generation engine.

After all, for China Aviation Industry, even the production of the second-generation turbofan 9 was quite difficult before this.

Therefore, in order to ensure that the project schedule would not be affected by material issues, Chang Haonan did not adopt particularly radical weight reduction methods in parts such as the casing and blades when conducting the overall design.

Typical fourth-generation engines, such as the F119, can even control the weight around 1450kg, thereby achieving a theoretical thrust-to-weight ratio at sea level of close to 11.

However, this is the part that we will pursue in the future.

Moreover, based on the current capabilities of Liming Factory, even after a comprehensive process upgrade, the speed of manufacturing turbofan 10 is still not optimistic.

After the hoisting step was completed, Haiyide heard a burst of slightly noisy footsteps behind him.

Looking back, I happened to see Chang Haonan leading someone in.

"Comrade Haonan, long time no see."

The two shook hands.

According to the division of tasks, after component-level testing, he, the chief engineer, is responsible for the manufacturing and final assembly of the first engine.

This is why Chang Haonan was able to spare time and go to Chengdu to stay for two months.

So after all, the two of them haven't seen each other for nearly a quarter.

For ordinary projects, if the chief engineer and chief engineer take turns to go online and often do not see each other for dozens of days, there is a high probability that trouble will occur.

But the situation of Turbofan 10 is quite special after all.

With almost all test content currently being successfully passed, wearing multiple hats does not seem to place too much of a burden on Chang Haonan.

Naturally, no one would raise any objection to this.

"We are still familiar with the improved test bench, and it is expected that the B0101 prototype will be ready for testing within two to three days."

After completing the command task, Haiyide hung the walkie-talkie back on his shoulder, and then led Chang Haonan to the nearby area while explaining the current work progress:

"The main reason is that compared to before, this test has a lot more backup gas-liquid actuating mechanisms that need to be connected. Not only us, but also the technicians from the 624th Institute have done it for the first time."

The latter raised his head and watched the field engineer on the operating frame begin to compare the drawings and carefully place the pipelines in various key locations of the engine.

Full digital control is a great upgrade for engines and aircraft, but it also creates a lot of trouble during testing.

Because once the electronic control system loses control, it cannot be shut down in an emergency like purely mechanical equipment, and may even endanger the safety of the high-altitude platform itself.

In particular, the Turbofan 10 is China's first model that plans to adopt this technology from the beginning of the design (it was tested earlier on the Turbojet 7).

The pipelines connected to the engine now function as an "external emergency backup".

Although the possibility of such serious accidents is very small if it passes factory testing, it is still necessary to take precautions after all.

"It doesn't matter."

Chang Haonan waved his hand:

“Part of the time I saved from previous design tasks was to leave room for production and testing.”

"There are always ways to improve efficiency at the theoretical and computational levels, but when it comes to the material level, we still have to be cautious and respect objective laws."

"Besides, before officially starting the test, we have to check the improved control rules of the bench system. This will also take a few days."

"I can't hold you back too much..."

Haiyide put his hands behind his back and said with some emotion:

"Compared with foreign countries, I felt that our development speed was no longer slow. But after working on projects with you in the past two years, I always feel that there is a force behind us pushing us to keep moving forward."

"It's obvious that these are all comrades who are responsible for the same project. There is no way to say that we are holding back. It's just a matter of learning from each other's strengths."

Chang Haonan waved his hand, then rubbed his neck, which was a little sore from looking up for a long time, and turned his attention to Haiyide again:

"By the way, Mr. Hai, how is the situation at Project 11 during this period? Especially the verification machine prepared for us?"

Although they are not the same system, Institute 601 and Institute 606 are both in Shengjing and can be considered brother units, and the Taihang Project is actually a part of Project , so some basic information can still be obtained.

Although he sometimes talks on the phone with Yao Mengna, who is almost based in Shengjing, but due to circumstances and reasons, it is impossible to talk about the project on the phone.

"The assembly of parts has almost been completed. The next step is to gradually increase the localization rate starting from the seventh batch, and then replace it with new domestically produced airborne equipment."

Haiyide replied:

"As for the replacement verification aircraft, Factory 112 will set aside a quota of a two-seater J-11AS for us to conduct installation experiments. I even took a special look before coming to Fucheng this time. The body structure has been almost completed. , but the main subsystems have not been installed yet.”

"The main reason is that the turbofan 10 uses digital electronic control, so the pipeline layout and flight control program will be slightly different from the current mass-produced model. We have to wait until we send the next batch of B0201 prototypes. in order to continue the production process.”

"If nothing else happens, it is expected to be delivered for test flight by the end of this year."

There is no difference in hardware between turbofan 10A and turbofan 10B. They even come from the same production line. It is just that the former limits the military thrust and maximum thrust values ​​at the control system level.

A bit like some car engines, as long as the external computer is refreshed to the second level, stronger performance can be unlocked.

In the file sequence within the aviation industry system, the two share the same production code, but the Air Force differentiates them at the equipment level.

Therefore, all other items except the life reduction test are conducted using the baseline model, and model A does not need to go through the process again.

After finishing this part of the conversation, Xu Yang, who had been waiting behind Chang Haonan just now, took a step forward:

"Next, I will introduce the simulation verification program of the digital control system. Come with me, next door."

The group walked around the high-altitude platform with dense cables hanging down, and came to the control room that was all too familiar to Chang Haonan——

He may be the person who has spent the longest time in this room outside of the 624 staff members.

Xu Yang still didn't say anything nonsense and directly pushed the information he had prepared long ago into Chang Haonan's hands.

As for herself...

Purely unscripted, no need.

"The system adopts open-loop control for the engine starting process. Considering the three starting methods in practical applications, namely electric start, compressed air start and propane gas start, the high-altitude platform test control system presets three different rules, respectively. It is a fixed time program fuel supply, a rotational speed function fuel supply and an appropriate fuel-air ratio supply.”

"There is no one-to-one correspondence between them. Since the turbofan 10 uses full-power digital control, in most cases, the speed function fuel supply scheme should be adopted, using the engine speed as the linear mapping quantity of the fuel flow..."

"..."

"The steady-state working process after startup adopts closed-loop control. Considering that both the J-11 and J-10 will adopt flight control systems integrated with thrusters, there is no need to consider the traditional physical speed control rate in this part, and the equal-reduced speed control is directly used. , the throttle command is directly sent by the flight controller through the communication port or in the form of a PWM signal, so the specific algorithm is exactly the same as what you left in the ECU program, so I won’t repeat it..."

"In addition, there are some extreme parameter restrictions for safety reasons, including physical speed, command speed, T4 temperature..."

"..."

Xu Yang talked for nearly two hours without any interruption, and he was obviously very familiar with the test control logic he designed.

After everything was over, she picked up the thermos cup next to her and took a drink of water:

"Do you think there's anything else you need to add?"

She is clearly very confident in the results of her work.

However, Chang Haonan did not give an answer immediately. Instead, he stared at the "modeling of the system's control objects and actuators" for a long time.

Ten minutes later, he finally raised his head again:

"I think... there should be more."