The military-industrial scientific research system of the academic master.

After both parties confirmed the details of the project and confirmed that they had no objections to the preliminary plan drawn up by Chang Haonan, Chang Haonan's 611, who was worried that Ye Changmengduo would be robbed again, submitted the project as quickly as possible.

Even though it was the busiest time at the end of the year, the project still got the green light from the Science and Technology Commission, and the entire process was completed in just a few days.

When Chang Haonan took the plane back to Shengjing, an engineer from the 611 Institute who had participated in the J-7F design work was already following him.

There were only some scattered test flight subjects that needed to be completed at the trial training base in the Eighty-three Project. There was no work that Chang Haonan needed to complete, so after landing, he rushed directly to 14, which was responsible for the performance adjustment of the turbojet 606 engine. graduate School.

Compared with the J-8C equipped with two engines, the J-7F, which is lighter, smaller and has a single engine, requires its own power to have higher reliability and lifespan, but its thrust requirements are not high.

For this purpose, 606 Institute has specially developed a new model, turbojet 14B.

There are not many specific changes, mainly by lowering the temperature in front of the turbine, sacrificing about 5% of the thrust, in exchange for a lower failure rate, and increasing the first turnover cycle from 150 hours to 250 hours.

At the same time, the power of the generator supporting the engine was increased from the original 18kw to 20kw.

After all, there is only one engine, but it has to drive a KJL7 radar with high power, and some margin must be left to deal with other subsystems.

Correspondingly, the model originally installed on the J-8C was named Turbojet 14A

This job is not difficult. Therefore, although the chief designer Yan Zhongcheng has focused on the design of the aeroderivative gas turbine of the Turbojet 14, others in the Kunlun engine project team still rely on the designs left by Chang Haonan. Experience completes the improvements.

This efficiency greatly exceeded Chang Haonan's expectations, and after some inspections, he determined that there was nothing wrong with the design of the turbojet 14B.

For China Aviation Industry in the mid-90s, it was very gratifying to be able to achieve this level of fine-tuning of engine performance at once.

"Factory 410 has started producing a prototype of this model. If there are no problems in the factory test, it will be sent to Chengdu for installation and matching in about two years."

This change is very small, especially for sub-models that reduce performance. Generally, there is no need to conduct complete ground and air platform tests as before.

However, Chang Haonan was not happy for long.

One morning two days later, he had just finished breakfast when he was stopped by Liu Dan, the deputy chief designer in charge of model improvement.

"Chang Gong, the news from the 410 Factory is that the turbojet 14B prototype broke down during the factory test."

After hearing these words, Chang Haonan, who was still a little sleepy, suddenly woke up.

He took several deep breaths to calm himself down.

Engine problems at this stage are not necessarily a bad thing.

Moreover, the failure was not an accident, indicating that the situation was not particularly serious.

"Let's go to Factory 410 and have a look."

……

The group soon arrived at the 410 Factory not far away.

The person in charge of the reception was Chang Haonan's old acquaintance, Zhong Shihong, the director of the technical department.

He led everyone to the testing workshop behind the production workshop.

An engine is being installed on the test bench.

The overall structure here looks a bit similar to the SB624 high-altitude platform of the 101 Institute, but it does not have the ability to simulate high-altitude environments. It is just a place to fix the engine and test whether it can work properly.

From the outside, this turbojet 14B has no damage.

It also verified Chang Haonan's previous guess that the problem should not be serious.

"This prototype was finalized in the afternoon the day before yesterday. Routine factory testing began in the evening, and the problem was quickly discovered."

Zhong Shihong walked to the control room next to him and called up the relevant test data:

"When the engine is at maximum thrust but the afterburner is not activated, the working condition of the compressor will fluctuate violently without warning. As of this morning, an alarm appeared in the combustion chamber. We shut down the engine to cool down and then checked. , it was found that the first-stage turbine blades had been damaged, but the test time had only passed less than thirty hours.”

"We have conducted many rounds of investigations, but in the end we still couldn't find the cause, so we can only contact you to see if we can determine what the problem is."

After hearing this introduction, what the 606 Institute was most worried about was not the prototype itself, but the turbojet 14A that had entered small batch production.

After all, it is related to the design and finalization of the J-8C.

However, it seems that this point has been estimated for a long time. Before anyone else asked, Zhong Shihong said that several turbojet 14A produced at the same time did not have similar problems and the test was completed very smoothly.

This made Chang Haonan sigh in relief, but also quite confused.

Most of the parts of the turbojet 14B are exactly the same as the turbojet 14A, so a large number of parts from the same batch will be directly used for assembly.

The result is that there is a problem with the model whose parameter orientation is low performance and high reliability?

This suddenly reminded Chang Haonan that when Yao Mengna was doing ground simulation tests for aviation engines in Fucheng, similar results seemed to have appeared during Yao Mengna's test of the temperature field distribution in front of the turbine.

When the throttle valve is near the minimum afterburner and maximum thrust, the temperature field distribution is the most unstable. If you continue to increase the thrust, the situation will gradually get better.

At that time, everyone could only locate the problem in the process of air film hole processing, and did not find a more specific reason.

Chang Haonan slowly walked to the test bench and picked up the damaged turbine blade from the table.

Because it uses air film holes for active cooling, it is covered with dense circular holes, which is extremely unfriendly to patients with cryptophobia.

"Minister Zhong, when you produce turbine blades, how do you process these film cooling holes?"

After hearing this question, Zhong Shihong's face showed a hint of pride involuntarily:

"The diameter of these small holes is only 0.25 to 0.30mm, which is difficult to process mechanically, so we can only use EDM deep hole processing technology. Our 410 factory specially changed the flow electrode of the 100A EDM machine tool into a hollow rotating copper for this purpose. The electrodes allow the coolant to flow in the copper tubes, and this is how we overcame the technical problem of short electrode life and manufactured the turbine blades of the Turbojet 14."

"Hmm...Is this the mainstream processing method in the world now?"

"That's not true. Western countries generally use electrohydraulic beam machining. However, our country's foundation in the field of electrochemistry is too weak, and related equipment is restricted and cannot be purchased. We have no choice but to use EDM drilling. this road."

Zhong Shihong shook his head as he said:

"However, the entire other processes of turbine blade manufacturing, including testing standards, are strictly controlled by the world's advanced levels. You can rest assured in terms of quality."

"The testing standards are also based on them?"

After hearing this, Chang Haonan finally realized.

"Then I probably know where the problem is."