Shen Damin is worthy of being a combat hero who has been baptized by gunpowder, a few words are not far from the war, those who know understand that Shen Damin is making analogies, and those who don't know think that China is going to do something again.

Fortunately, it didn't take long for the radio at the station to notify the ticket inspection to get on the train, which interrupted Shen Damin's interested statement, but just as he finished checking the ticket and boarded the train that was about to start, he suddenly poked his head out of the window and shouted loudly at Meng Jianye: "Go back and tell Liang Mingqiu that I have passed the matter with his grandfather!"

Hearing this, Meng Jianye was a little stunned, but when he wanted to say something, the train that Shen Damin was riding had already started, and he took Shen Damin to face the howling north wind and gradually moved away.

But after turning around, Meng Jianye smiled knowingly, he didn't want to participate in the grievances of the older generation, but he didn't want them to repay each other, so it was good to be able to let go!

……

According to the best parameters given by the design team led by Professor Qin, the root of the four-bladed propeller blade is a wing cross-section, so that it can provide greater thrust under a smaller torque.

The upper part of the blade is rounded to reduce cavitation and erosion, and the inclination angle of each blade is 8.5 degrees, which can not only reduce the vibration of the blade, but also reduce the impact of noise as much as possible.

All in all, these two propellers are not the highest level in China, but they are also in the forefront, and the manufacturers who can make this kind of propellers have to say that their technical strength is really not to be said.

From this point of view, Endeavor Factory still has a long way to go in this regard, so Liang Mingqiu, Niu Chen and others did not go back with Meng Jianye, and continued to stay in a large factory to learn their skills with peace of mind.

……

In this way, another week passed, and Meng Jianye finally returned to the Endeavor factory with two propellers, and at this moment, two months had passed since the start of the construction of the No. 389 minesweeper.

Thanks to technological innovations in welding, the welding of damaged parts of the No. 389 minesweeper was carried out smoothly, although the addition of drying, moisture-proof and preheating processes made the welding process more complex and the efficiency was slowed down.

Fortunately, there were not many damaged parts of the No. 389 minesweeper, and the number of welders in the Endeavor Factory was not a lot, so under the three shifts of the welders, when Meng Jianye returned to the Endeavor Factory, most of the welding work was nearing completion, and the rest was some corners and sub-item acceptance.

As for the ship's pipelines, cables and instruments, all of which had been completed before Meng Jianye returned, a major problem that had plagued the No. 389 minesweeper, the vibration and noise problems of the power supply equipment, were also successfully solved with the joint cooperation of Sun Hongjie and Zhen Jia, two "noise reduction experts".

For this reason, it was also praised by Dong Yimin, chief of staff of the N Fleet, who came to inspect the N Fleet on the way.

Because Sun Hongjie and Zhen Jia did not ask for a new power supply unit like most experts, but optimized the original power supply unit and carried out a comprehensive noise reduction treatment, to put it bluntly, the set of dealing with engine noise was done to the power supply unit.

Eight groups, 16 series and parallel shock absorbers, improved noise-reducing shells, and if it weren't for the fact that the power supply unit did not have engine intake and exhaust requirements, it is very likely that both of them would have gotten the mufflers up.

After such a comprehensive treatment, the noise of the power supply unit has been reduced from the original 121 decibels to 75 cents, and the effect is quite good.

It dropped by 46 decibels, and it is no wonder that Dong Yimin, who was stingy with praise, praised Sun Hongjie and Zhen Jia, because their achievements not only solved the biggest noise source of the No. 389 ship, but also saved a lot of money for the N fleet.

There is no way that the price of things on warships is not cheap, especially large-scale supporting equipment such as power supply units, which not only has high technical content, but also has high parameter requirements.

If this is the case, it will not be good news for the already tight N fleet.

Therefore, Sun Hongjie and Zhen Jia's improvement of the original equipment is equivalent to saving valuable funds for the N fleet, so even Dong Yimin, who no longer likes to praise people, must be flexible.

It's just that Dong Yimin's praise this time did not get the fuss of Endeavor Factory, and even Jiao Dalin, who valued the comments of the old instructor, felt that this was reasonable.

Because Meng Jianye had already pre-evaluated the noise reduction scheme before going to the Han'e Shipyard to participate in the model test of the 389 ship, and after arriving at the Han'e Shipyard, using the resources of the shipyard, Meng Jianye improved the initial scheme on the computer, and obtained more accurate parameter values and process specifications.

With such a scientific and rigorous demonstration and plan, coupled with the original familiarity of Endeavor Factory in noise reduction and shock absorption technology, not to mention that the power supply equipment of 121 decibels has dropped by 46 decibels.

Even the two 1,100-horsepower D-80 diesel engines have been reduced from 133 decibels to 103 decibels.

In the eyes of others, this effect is already a great achievement, but Meng Jianye still has some regrets, because according to his original assumption, the noise value can be reduced by about 5% to 8%.

However, the materials really can't keep up.

Despite the participation of the N fleet, the slag wool and slag boards that Endeavor had been looking for were available, but the number was very limited, barely enough for two 1,100 hp D-80 diesel engines.

When it comes to the power supply unit, you can only use the old method, at most thickening the asbestos, felt and pumice slabs.

As for Meng Jianye's leemiculite slabs, even the N fleet can't get them, it's not that there is no domestic production, but the output is too small, the quality is unstable, and the only pitiful production is all used on submarines, and in desperation, the noise-reducing shells on the No. 389 minesweeper are still pumice slabs.

Then there is the special rubber used for shock absorbers, the batch of special rubber produced in the Soviet Union from the excellent factory is not much left after the consumption of the cruise ship, and the 389 minesweeper is a warship with higher noise reduction indicators, so the special rubber is consumed more.

Eight groups of sixteen shock absorbers were used on the power supply unit alone, and two 1,100-horsepower D-80 diesel engines were each equipped with twelve groups and 22 shock absorbers.

This is not counting, in order to reduce the noise of the shaft system operation, the inner diameter of the transmission shaft tube wall should also be filled with a layer of special rubber, so that the few special rubber in the Endeavor factory immediately used seventy-seven eighty-eight.

So much so that Endeavor had to reduce the amount of special rubber on the cruise ship in order to save it for the repair of the No. 389 minesweeper, and in the end, the tandem double-layer shock absorber on the cruise ship was changed to a hard spring shock absorber without special rubber, which was barely the demand of the No. 389 minesweeper!