"Skilled workers are also part of the production line, right? Is there anything wrong with what I said?" Zheng Yucheng asked embarrassedly when he saw that the people around him were looking at him with a smile.

"That's right, that's a good idea, very good!" Xie Kai held back a smile, "Lao Zheng, don't you think you're too insidious? If McDonnell Douglas people know, do you think they will hunt you down all over the world?"

"Why did you become my insidious? Zheng Yucheng said in surprise.

When it comes to emptying the 5703 factory and how to operate it, it was obviously proposed by Xie Kai.

Of course, he also mentioned that it is definitely not as perfect as the plan Xie Kai said.

"Yes, do we still want to do business?" Du Shengfeng was secretly surprised in his heart, no wonder Zheng Yucheng took this kid with him wherever he went, not a fuel-efficient lamp.

It's a shame that I didn't offend this kid, otherwise I don't know when I will be yin in the future.

"What's going on with Qin Fei's Yun Shi here?" Zheng Yucheng asked Ma Fengshan as he walked.

Two hundred hours of safe flight time have passed, and now, the first test flight prototype has flown for 237 hours, and the position of the weld of the main frame beam structure has begun to appear subtle cracks.

How to solve this prototype now, whether to continue the test flight after rebuilding it and get more flight data, or simply stop the test flight altogether and wait until the other one is assembled and continue to test the flight, we must come up with an idea.

"Our opinion is to re-weld and then continue the test flight!" Ma Fengshan said heavily, "There are many problems with the new one that cannot be exposed." ”

"Haven't we gone through finite element analysis, how much is the difference between the calculated data of the simulated structural strength and the actual data?" Xie Kai asked.

Yun Ten was already aware of these issues when they took over.

So no one is looking at how the problem came about, or how the problem was created.

The reason for these problems, they all know that the lack of large presses, the production of core parts of the structural parts can not reach the design strength.

Hundreds of tons of flight weight are constantly flying in the sky, so that the aircraft bears all the gravity of the key cracks, everyone knows it.

"The actual situation is not much different from the data from the simulations. After the assembly of the other aircraft, the safe flight time can be increased to 300 hours, which is also useless for commercial aircraft. Mr. Ma said.

"Can you increase the time so much?" Xie Kai was curious, "Aren't they all using the same processing method and assembly method?"

"The production of parts and components has gradually improved the strength and structure problems since the first prototype flight test flight of Yunshi was introduced, and the process adopted during assembly has also been improved. Mr. Ma explained, "However, in the production process of the main structural parts, there is no large press, and the large forgings cannot be formed at one time, and the small forgings are still spliced in the end......"

It is still a problem caused by the lack of critical processes.

"In this way, as long as the big press can't be built, the problems faced by Yunshi can't be effectively solved?" Zheng Yucheng asked with a bitter face.

The more I think about it now, the more I feel that it was too ideal.

"Yes, the 45,000-ton press can solve these problems. The frame beam structure of the main structure part can be forged and formed at one time and processed as a whole to solve this problem, otherwise the problem that the structural strength cannot reach the design life cannot be solved. Ma Fengshan said.

Several people had already walked outside Qin Fei's Yunba assembly workshop.

Yun Shi, who had a huge body, was parked alone on the huge runway outside the assembly workshop.

From the outside, you can't see what's going on inside the plane at all.

Under the leadership of Ma Fengshan, several people got on the plane, and inside the plane, especially in the middle of the fuselage, some of the interiors have been disassembled, and the structure of the fuselage frame beams can be clearly seen.

Some of the designers of the original Yun-10 team are conducting various inspections inside the cabin, constantly recording them in their notebooks.

"There are no cracks. No matter how Zheng Yucheng looked, he couldn't see the cracks on the welds on the plane's girders.

"You can't see it with the naked eye, you can see it clearly with a magnifying glass. Ma Fengshan took a magnifying glass from the staff next to him and handed it to Zheng Yucheng.

Zheng Yucheng put the magnifying glass close to the weld, and when he put it up again, he found a crack as thin as a hair.

"There are not too many places on it, and the more you get to the point where the cabin bears the weight, the denser the cracks become. During the inspection, these cracks were discovered, so I stopped flying now......" Ma Fengshan led a few people down the ladder to the cargo hold on the belly of the plane, pointing to the exposed position of the frame beam at the bottom.

The bottom bears the weight of the whole aircraft, because it is not formed at one time, and is connected by welding method after segmented forging to form a long sorghum that bears the weight of the entire aircraft.

In some places, even without a magnifying glass, dense cracks can be seen under the light provided by the flashlight.

The surface of the aluminum alloy is smooth, and you can see clearly if there is a little abnormality.

"If this plane is going to continue flying, the girder will have to be replaced. Ma Fengshan looked at Zheng Yucheng and said in a low voice.

"Aren't there cracks in other frame beam structures?" Zheng Yucheng was puzzled.

"Again, we have to test and replace at the same time, so that we can get a more comprehensive data. Ma Fengshan said.

Xie Kai has been observing the various main part structures inside, and there is a problem with the core structural parts, and there is a problem with the sorghum that bears the weight of the entire aircraft, and there is no need for this plane to continue flying.

It must be scrapped.

Otherwise, at the time of the next flight, there is a risk of disintegration.

"Scrap it!" Xie Kai sighed.

No one wants to accept such an outcome, but they have to accept it.

"Replacing the girder, frame beam structure, can be re-flown without affecting safety. This will result in cost savings of at least three-quarters compared to remanufacturing. Ma Fengshan hurriedly said.

They think about cost.

404 raised their own funds so that the Yun-10 aircraft could continue, and they couldn't help but think about cost savings.

"Your opinion is scrapped?" Zheng Yucheng wanted to remind Xie Kai that the cost of an aircraft was tens of millions.

Even if the main structure can't be used, some other things can still be used.

"Mr. Ma, I know that you are thinking about cost savings. As you said, just replacing the girder, etc., the cost is less than 10 million, but if the new girder and the main force frame beam cannot solve the strength structure problem, the original processing technology is still used, and the final flight is only another 300 hours...... Just the cost of replacing these core structural parts, even if it is calculated according to six million, it will cost 20,000 yuan an hour!" Xie Kai calculated the cost to Ma Fengshan.

These costs do not include the cost of man-hours, the cost of fuel required during the test flight, etc.

"If you don't keep flying, there are some hidden faults that won't be exposed. "Mr. Ma is also aware of the facts that Xie Kai said.

Several people got out of the plane and stood aside to watch the plane quietly parked on the runway, all of them with mixed thoughts.

The outside is shiny on the outside, and no one knows what is going on inside.

If you remove the outer skin, you may also find that there will be various problems with the welded positions of the main body of the fuselage.

There are no large forging presses!

Critical structural parts are not able to withstand the tremendous impact forces of take-off and landing.

"Is there a problem with the landing gear?" Xie Kai asked.

"It has not been checked out yet, and according to the results of finite element analysis, at least another 300 sorties can be flown again. This is forged by a 30,000-ton press, and although the structural strength does not match the design, it can barely be guaranteed. ”

"Is this the best news we've heard about Yun Ten so far?" asked Zheng Yucheng jokingly. "A lot of aircraft accidents happen because of the landing gear. ”

But no one could laugh.

The state has invested more than 500 million yuan, and now, such a result has appeared.

Keep flying, no one dares to guarantee that in the next flight batch there will be no disintegration.

Metal fatigue, when the original service life is not reached, unless there are external factors, it will not cause potential safety hazards.

Once the limit is reached, cracks begin to appear, and if you continue to use it, this failure will quickly magnify.

The main girder broke, and the entire aircraft disintegrated.

"We can't risk the future of large domestic aircraft. Not to mention that there are so many cracks, even if there is only one crack, it should be scrapped, and you can't take chances. In this regard, we should not save on the tuition fees. Zheng Yucheng said to Ma Fengshan.

The General Administration of Civil Aviation has now abandoned large aircraft, and the state no longer invests, but they cannot hold out any hope for the entire domestic large aircraft for such reasons.

In order to save tens of millions of dollars, we should not let the faulty aircraft continue to carry out test flights.

"This aircraft can be used as an experimental platform, whether it is the operating system or other electronic systems, it can be verified on it. The new design modification work will be the focus of the next step. As long as there are no problems with the design, we can start with the production of some other non-critical components before that. As soon as the big press comes out, the first thing to do is to assemble it directly, and then it can be directly assembled, and you can continue to test the flight!" Zheng Yucheng comforted Ma Fengshan.

Mr. Ma's thoughts, Xie Kai understands very well, he doesn't want this 110-ton large aircraft that can fly for the first time in China to never fly again.

"As long as it does not disintegrate, on the ground, the significance of this plane will be no worse than flying in the sky. Xie Kai said to Ma Fengshan, whose eyes were slightly red. "Get ready to produce a new design of the aircraft!"

"Start preparing now? The big press hasn't started yet. Du Shengfeng asked.

"Ready, don't you understand?" Zheng Yucheng's eyes widened.

Ma Fengshan knew that the two of them were comforting him, and it was also a sign of the 404's determination in the cause of large aircraft, and his heart was much more comfortable.