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 ran all the way. We arrived upstairs at Guo Jingshan, chief engineer of the 602 Institute.
He is also the general person in charge of the introduction and imitation work of Zhi9.
You must know that this project, like the J-7F, was first started by the 602 Research Institute and the 122 Factory by raising a huge sum of 320 million yuan (currency value in the 1980s). Several units participating in the project all had this purpose. And being heavily in debt shows his courage and courage.
However, to engage in research and development in the aviation industry, courage and courage are not enough.
Today's Bingcheng Aircraft Industry Group is troubled by the localization rate and reliability problems of the navy 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 whisper softly into Guo Jingshan's office called out.
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 really difficult to see who the person was. who.
But those who came here looking like this must be the technical staff of the institute.
"You go ahead and put the things down."
Guo Jingshan straightened the hair that was only around his ears and motioned for the visitor to put the things on his desk.
Then he saw the identity of the other party:
"Are you... the new little king who graduated last year, Wang Zhilin?"
Logically speaking, he is the same It is impossible for the chief engineer of the institute to remember every newcomer in the institute, but 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 that he will leave 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 above the straight 9 - of course, this In fact, it is not difficult. After all, the only helicopter models that have actually landed in 602 are Z-5 and 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 French design, a big problem.”
"Oh?"
Guo Jingshan's eyes, which were smiling just now, suddenly became sharp:
"Where exactly?"
"The tail output of the main reducer The strength margin of the bevel gear pair is insufficient.”
Wang Zhilin pulled out a drawing from below and pointed to several positions 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 subsequent models, as the engine power continued to increase, the maximum load endured here during flight also increased. is increasing, and the French Aerospace Company only added the vibration polishing process of the tail output bevel gear to improve its surface contact strength, but did not modify the structure itself, so..."
"So we copied it. model, the tail rotor transmission mechanism is always operating under high load?”
Guo Jingshan was also a little confused after hearing this.
A very outrageous cause of the malfunction, but if it were a French person...
It seems less outrageous.
"Yes, and the original design of the French was like this."
Wang Zhilin nodded and continued to explain:
"Our original standards for helicopters Even if they copied the French military standard, the French could not detect it. If we copy it again, we will definitely not be able to detect it. Today, I had a sudden idea and checked it with the new military standard that was just issued. I immediately found something wrong... ”
Industrial standards are the same as laws. They must not be retroactive, otherwise there will be chaos.
Therefore, 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. As for whether these equipment should continue to use the old standards or switch to new standards, even Chang Haonan cannot give a one-size-fits-all approach to decide.
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 pause, Wang Zhilin continued to add:
“But I already have a preliminary improvement idea, which 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. The strength margin can be improved without changing the shaft intersection angle, transmission ratio, and steering. The only price is that the volume of the engine fairing must change. Large, 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 simply do not do it. The life of the planetary gear bearings and the lack of emergency lubrication System problems can also be solved in the process of this shipboard modification..."
"Although I have not made detailed calculations, it is preliminary estimated that if these measures are implemented, they will at least be able to The maximum take-off weight of the aircraft has been increased from 4 tons to 4.5 tons, and the external load has also been increased accordingly. It can at least ensure that it can carry submarine search equipment and two anti-submarine torpedoes at the same time. In addition, the range has been increased, and it can satisfy the requirements of the Army Aviation Corps even under large load conditions. Requirements for flight across target straits and medium- and long-distance anti-submarine warfare for ship-based helicopters..."
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.
Many of the contents here were what he thought of while waiting for the results.
“Xiao Wang, what you are talking about is actually the next key research area for our group, the localization and improvement of rotors, tail rotors, and main reducers. We also applied for Seiko in the middle of the year. A planned project.”
Guo Jingshan looked pleased at first, but then he looked embarrassed:
"But the Z-9 is still being delivered in series, and there is really no condition at the moment..."
"Can you consider asking the French Aerospace Company to improve the delivered parts? After all, they have their own model I have the same problem..."
"It's difficult."
Wang Zhilin was interrupted by Guo Jingshan raising his hand in the middle of his thoughts:
"After 90 years. Although the French manufacturing factory was still delivering the ordered engine parts to us, the technical team of their design unit had all withdrawn and stated that they would not respond to any of our technical requests. Later, we tried to contact us several times. , and all of them were rejected. Otherwise, with a full set of technical information, the delivery of Zhi 9A would not have been delayed until this year.”
"In this case, is it possible to put a hot face on someone's cold butt?"
"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 on the 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 god 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 when 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, saying that our main reducer is available!"
The two people who were immersed in the drawings looked up almost at the same time. Door:
"Huh?"
"Really?"
(End of this chapter)