The Military-industrial Scientific Research System of the Academic Master Chapter 451

Chapter 451 Helicopter Main Reducer

Wang Zhilin, who finally discovered the problem, murmured his gratitude to the tutorial author, quickly picked up a stack of calculation drawings spread out on the table, and jogged upstairs to Guo Jingshan, chief engineer of the 602 Institute.

 He is also the general person in charge of the import and imitation work of Zhi9.

You must know that this project was first started by the 602nd Institute and the 122nd Factory by themselves, like the J-7F, with a huge sum of 320 million yuan (currency value in the 1980s). Several units participating in the project were all heavily in debt for this, which is enough to show that His courage and courage.

 However, to engage in research and development in the aviation industry, courage and courage alone are not enough.

●Today's Bingcheng Aircraft Industry Group is troubled by the localization rate and reliability issues of the naval and army armed types.

“Mr. Guo, Mr. Guo, I found a problem!”

Wang Zhilin had both hands occupied and it was not convenient to knock on the door, so he had to stand at the door and call softly into Guo Jingshan's office.

The latter, who was immersed in the table, raised his head and saw only a figure standing at the door. However, because the upper body was almost completely spread out and covered by the half-rolled drawings, it was difficult to see who it was.

But those who come here with this appearance must be the technical staff of the institute.

 “You go ahead and put your things down.”

 Guo Jingshan straightened his hair, which was only on the sides of his ears, and motioned for the visitor to put things on his desk.

 Then he saw the identity of the other party:

"You are...the new little king who graduated last year, Wang Zhilin?"

Logically speaking, as the chief engineer of the institute, it is impossible for him to remember every newcomer in the institute. However, Wang Zhilin is very outstanding among his group of newcomers, especially in the field of numerical calculation, which has been very popular recently, so it is inevitable to retain some impression.

 “Yes, Mr. Guo, I am Wang Zhilin.”

Wang Zhilin nodded while sorting out the messy drawings.

 “What problem did you just say you found?”

Guo Jingshan, who put on his glasses again, recognized at a glance that the transmission system on the drawing was that of the Z-9. Of course, this was actually not difficult. After all, the only helicopter models that had actually landed in the entire 602 were the Z-5 and the Z-9. , and even a novice who has never studied aviation can see the difference between the two.

 “I found something wrong with the original design of the French. There were big problems.”

"oh?"

Guo Jingshan, who was smiling just now, his eyes suddenly became sharp:

 “Where exactly?”

“The tail output bevel gear pair of the main reducer has insufficient strength margin.”

Wang Zhilin pulled out a drawing from below and pointed to several locations circled in red pencil:

"I checked the original design materials provided by the French side. Because the Dolphin was actually developed from the Skylark helicopter, I borrowed a lot from the original design and designed the current main reducer on the first model SN365. , I calculated that the maximum transmission power of the tail output bevel gear is 220kW.”

“In the subsequent models, as the engine power continued to increase, the maximum load endured during flight also increased, and the French Aerospace Company only added the vibration polishing process of the tail output bevel gear to improve its surface contact strength, but The structure itself has not been modified, so..."

“So the model we copied actually has the tail rotor transmission mechanism operating under high load all the time?”

Hearing this, Guo Jingshan was also a little confused.

 Very outrageous cause of failure, but if it were a French person...

 It seems to be less outrageous.

“That's right, and that's the original French design.”

Wang Zhilin nodded and continued to explain:

"Our original standard for helicopters was copied from the French military standard. Even the French couldn't detect it. We will definitely not be able to detect it if we copy it. Today I had a sudden idea to use the new national military standard that was just issued. After a while, I immediately realized something was wrong..."

 Industrial standards are the same as laws. They must not be retroactive, otherwise there will be chaos.

 So in principle, projects that have been completed before the new national military standards come into effect should continue to use the old standards to ensure the continuity of use and maintenance.

 However, due to China's special circumstances, there are still a large number of projects that have been nominally completed, but in fact only part of them have been completed.

 Zhi9 is one of them. Even Chang Haonan cannot give a one-size-fits-all approach to decide whether these equipment should continue to use the old standards or switch to new standards.

 It can only be decided by the respective project teams.

 Fortunately, the standards specific to helicopters mostly include additions and few changes, so there is no risk of overturning the entire model and starting over.

 After a short pause, Wang Zhilin continued to add:

"But I already have a preliminary idea for improvement. I can increase the module of the bevel gear pair and increase the tooth width appropriately. In this way, the installation position of the large bevel gear remains unchanged and the small bevel gear moves backward, so that the shaft intersection angle, The only cost of increasing the strength margin without changing the transmission ratio and steering is that the engine fairing volume must become larger, but for helicopters, there are not many parts that need to be considered for the aerodynamic shape..."

“In addition, since we have decided to modify the main reducer, we might as well do it without stopping. The problems of planetary gear bearing life and lack of emergency lubrication system can also be solved during this shipboard modification process..."

"Although I haven't made detailed calculations, it is preliminary estimated that if these measures are implemented, they can at least increase the maximum takeoff weight of the aircraft from 4 tons to 4.5 tons, and the external load will also increase accordingly. At least it can ensure that it can carry submarine search weapons at the same time. equipment and two anti-submarine torpedoes. In addition, the range is increased, and even under large load conditions, it can meet the requirements of the Army Aviation Force across the target strait and the mid-to-long-distance anti-submarine flight requirements of ship-based helicopters..."

Yang Yangsao, Wang Zhilin put forward many suggestions for improvement.

The slow calculation speed of the computer is not all bad, at least it gives him enough time to think.

 A lot of the content here was what he thought of while waiting for the results.

“Xiao Wang, what you are talking about is actually our group's next key research area, the localization and improvement of rotors, tail rotors, and main reducers. We also applied for a project under the Seiko Plan in the middle of the year.”

Guo Jingshan looked pleased at first, but then he looked embarrassed:

“But Zhi-9 is still in the state of serial assembly delivery, and there are really no conditions at the moment..."

“Can you consider asking the French aerospace company to improve the parts delivered? After all, their own models also have the same problem...”

  “It's difficult.”

Wang Zhilin was interrupted by Guo Jingshan raising his hand when he was halfway through his thoughts:

“90 years later, although the French manufacturing plants were still delivering ordered engine parts to us, their design unit's technical team had all withdrawn and stated that they would not respond to any of our technical requests. Later we tried I contacted them several times but got no response. Otherwise, with a complete set of technical information, the delivery of the 9A would not have been delayed until this year. "

“In this case, is it possible to put a hot face on someone's cold buttocks?”

"this…"

 Obviously, the latter is right.

 But Wang Zhilin is still a little unwilling:

 “Then let's improve the straight 9...”

“Let's take it step by step. Now at least we have a clear direction to solve the problem. All that's left is to chew hard bones one by one…”

Guo Jingshan sighed softly.

Everyone wants to solve the problem in one step, but for China Aviation Industry, there are indeed few such opportunities.

 He ​​has been in the industry for more than 30 years, and he only heard that he met such a **** when the 606 Institute was engaged in turbojet 14 last year.

It's a pity that they are not in the helicopter business.

 Although both fixed-wing aircraft and helicopters can fly, the basic principles are very different. Under normal circumstances, few people cross the border like this.

 “Okay, then I…”

Just as Wang Zhilin was about to pack his things and return to the office, a rapid knock on the door came from behind him.

“Mr. Guo, there is a call from Factory 122 to tell you that our main reducer is available!”

The two people who were immersed in the drawings looked up at the door almost at the same time:

"ah?"

"real?"

 (End of this chapter)

Chapter end