Colombo felt that the sentence structure of Gambailey's sentence was a little strange, but because his main attention was on the heavens, he didn't think too much about it, just shook his head, and said in a firm tone:

"I've been in contact with the Huaxia since two years ago, when I was still in Agusta, and I was here, but at that time we were working with a propeller airliner, like the ATR72."

"I'm sure they didn't have that much technology at the time."

Gamberry looked at it with some confusion:

"MA60, I know, our company's first fixed-wing product, but if their technical level at that time is not good, why should we choose to cooperate?"

As an engineer specializing in helicopters, he has only a slight understanding of the company's newly established fixed-wing business unit.

Specifically, after making sure that the existence of the other party would not affect the status of his side and the resources he obtained, he didn't pay much attention to it.

"It's similar to this plane, although other places are average, but the core competitiveness is very strong, and it can save about 8% of fuel compared with passenger aircraft of the same level, which is what many airlines dream of."

Colombo lowered his head again as he spoke, rubbing his somewhat sore neck:

"And then there's the fact that their technology is advancing very fast."

"The first time I came to China, when I saw the MA60, it still looked very simple, and there were a lot of shadows of the Soviet An-24 transport plane."

"But just six months later, the other aircraft is completely different, and, in addition to the fuel economy card, they have also replaced it with new propellers and flight control systems, which reduce the noise in the cabin to the level of a typical turbofan airliner."

Hearing this, Gamberry felt as if he had grasped the point:

"In other words, they started working on propeller noise reduction technology from that time?"

However, Colombo shook his head decisively:

"That's not it, the noise reduction principle of MA60 is to control the phase difference of the left and right propellers, so that the medium and low frequency noise emitted by them cancels each other, which is equivalent to some kind of active noise reduction measure, and it is only effective for the interior of the cabin, and it is still very noisy to listen to outside."

"But there is obviously no possibility of this in a normal structure helicopter, the main rotor and tail rotor are hard coupled through the transmission mechanism, there is no way to adjust the phase difference, and their noise level is not at the same level, which cannot be compensated."

"So this time, we must have worked on the noise sources such as the rotor and the fuselage."

Gamberly opened his mouth, but couldn't say a word.

The main thing is that I really don't know what to say.

Adjusting the phase difference of the propeller to achieve active noise reduction may sound simple in principle, but anyone with experience in engineering control knows that theory and practice are two different things.

If you really want to implement it, it's another matter.

At about the same time, they developed another way to reduce noise from the source of the noise.

Even now, he has not fully understood the technical means of the other party to achieve low noise......

It's a bit embarrassing to say.

In his heart, Gamberley raised the importance of this cooperation a little more.

If before he came, his main idea was the same as that of Bell or Westland, which was to simply find a wronged boss to share the risk together.

So now, he has begun to regard the other party as a core competitiveness.

The previous investment in the MA60 was undoubtedly a gamble.

But both from Colombo's personal point of view, and from Agusta's point of view, it now seems that the bet has been won.

For the former, he relied on the good relationship he had with Huaxia in this project, which led to a higher level of cooperation between the two parties in the future, and he also asked for a wife by the way.

For the latter, MA60, as a new model provided by a new supplier, has already obtained a total of more than 20 orders in Thailand and China without completing the finalization and certification process, and it is obviously expected in the future.

If you can replicate the successful experience in the field of helicopters......

Thinking of this, Gamberley rubbed his hands almost involuntarily, revealing an expression of eagerness.

The prototype of the Z-9WY quickly completed the scheduled two laps around the field and re-landed on the tarmac.

Unlike passenger aircraft, helicopters usually work normally to load and unload cargo or personnel during engine starting, so there is no safe zone around ordinary aircraft except near the tail rotor.

And the dolphin's ducted tail rotor is even safer.

Therefore, after the helicopter stopped, while the pilot had not turned off the engine, Gamberly hurriedly ran to Cui Wenxue and Chang Haonan not far away, and asked if he could take a closer look while the plane was working.

Although this plane belonged to the Bingfei Group, theoretically the former should have the final say, but he still looked at Chang Haonan who was standing next to him.

Who is the real person in this round of cooperation, Cui Wenxue still knows clearly.

Chang Haonan directly stretched out his hand and signaled to Gamberly to be casual.

The latter was also not polite, skillfully opened the cabin door, took out a device to test noise from his bag, and got into it alone.

Not only can the device measure a simple decibel level, but it can also analyze the waveform of the sound to determine the proportion of each frequency band in the noise.

About five minutes later, Gambelli, who had been sweating in early spring, got out of the cabin again.

The results of the equipment were similar to what he had heard.

The total decibel level does not change much, but annoying pulses are almost completely eliminated.

Most of the noise falls in the range of the high receptivity of the human ear, that is, the sound of the turbine engine itself.

The ultimate manifestation is that the helicopter feels more like a small business jet when it is working.

This will be more comfortable for passengers inside the cabin.

For those outside the cabin, the proximity of high-frequency noise will also reduce the impact of low-flying helicopters on ground personnel.

No matter how you look at it, it's a lore.

Intellectually, Gamberry is fully aware of the value this technology can bring.

But emotionally, he still had a hard time convincing himself.

If a new technology has no disadvantages at all compared to existing technology, it means that it has completely surpassed its time.

But Gamberry really couldn't understand it.

Why the Chinese?

He has no prejudice against any country, but this is really not in accordance with the laws of science.

The Huaxia people have hardly any previous achievements worth mentioning in the field of helicopters.

Now come up and just dump the king and bomb it?

"Will this low-noise propeller have problems in terms of aerodynamic efficiency?"

Gamberry asked the question with great mixed feelings.

He didn't even know what answer he was expecting.

On the one hand, he wants the other side's technology to show some shortcomings in at least one other way, because it means a "trade-off" rather than an all-round crush.

But on the other hand, he wants a negative answer, because in any case, he has already decided to apply the new technology to the new helicopter he is planning.

And Chang Haonan had already predicted that they would have similar problems.

Because from the perspective of rotor design alone, efficiency and quietness are indeed a pair of contradictory performances.

He looked at Liu Hongbo and Guo Jingshan, who were standing not far behind him:

"Show Dr. Gambley the technical manual for the aircraft."

Soon, a document that had been prepared long ago, in both Chinese and English, was handed over to Gambailey.

Among them, it even writes murderously compared with the original dolphin.

The data is so detailed that it can even be found in the engine output power curve.

Of course, this is not a temporary production recently, but used as promotional materials when I participated in the Singapore Airshow before.

It's just that the last few orders were from small African countries, and people didn't look at these things at all.

Just compared it with the naked eye of the AS365N1 next to him, and simply signed the order neatly.

directly staged a play of the original drama of the same people forcing death -

Although the workmanship and longevity are indeed a little worse, it has more features (armed), better performance (long hovering time), and is also cheaper.

What kind of bicycle do you want?

As a professional in the field of helicopter design, it was only natural that Gamberley found the key data directly.

The results are obvious.

While the rotors themselves did suffer some damage, the redesigned drivetrain allowed more engine power to be efficiently delivered to the rotor ends.

In comparison, the efficiency reduction of about 3% is not worth mentioning.

It's okay to even think of it as a test error.

As an aeronautical engineer, Gamberley can certainly see the correlation between these data, and he is not just writing and deceiving people.

Besides, the test flight just now can't be fake......

"Unbelievable ......"

"How the hell did you do that?"

Gambailey asked directly to Chang Haonan behind him.

He also saw this wave that it was not Cui Wenxue who could really call the shots in this cooperation.

It's this inconspicuous young man who has been standing next to him before.

"Generally speaking, it is to calculate the flow field characteristics of the rotor and fuselage assembly during flight, focusing on capturing the shock wave and the propeller tip vortex, because while the rotor vibrates and emits a pulsed sound, it will also induce these two flow states, and then through integration to obtain the far-field sound pressure characteristics, it can relatively accurately calculate the sound field laws generated by the main rotor of different shapes and specifications......"

"As for the more specific technical details, after the cooperation between our two sides is reached, the engineers of our Torch Group and Bingfei Group will make more detailed explanations."

Chang Haonan's answer is basically equivalent to Bolt saying that as long as you take turns to open your left and right legs, you can win the gold medal in sprinting.

Everyone understands the truth, but obviously not everyone can be as fast as him.

Gamberry also knew that it was impossible to set out the core technology of others here, so he asked a more theoretical question:

"CFD calculations? So how do you ensure the accuracy of the calculation of unstructured meshes? ”

After asking, he felt that the question might cause some ambiguity:

"What I mean by this is that the finite volume method (FVM) can usually only achieve second-order effective accuracy in the field of compressible fluids, and in the past, it was certainly enough to calculate the aerodynamic efficiency and so on, but if you calculate the sound field according to your ideas, the error must be very large."

"We don't use FVM for CFD calculations, because FVM is not in principle possible to achieve a high-precision numerical format for unstructured meshes."

Chang Haonan replied with a smile.

During the time when the two were talking, the members of the Italian delegation, who had just withdrawn to a distance, gradually gathered around.

Therefore, he deliberately raised his voice slightly to ensure that anyone other than Gambley could hear it.

"In terms of high-precision finite element calculations, there are some special techniques to solve the problems of numerical oscillations, or the physical properties of windwards, so that the calculation accuracy and computational efficiency can be guaranteed at the same time."

"This is also the latest research result of our Torch Group in the field of numerical computing."

While speaking, Chang Haonan turned around slightly and glanced at the surrounding circle of Italians.

Sure enough, the eyes of several of them changed immediately.

In fact, he had known for a long time that the delegation sent by Italy this time was not only members of the Agusta company.

The passage just now is also for this part of the people.

……

The group stayed in the outfield until lunchtime.

In the case of foreign guests, even from the perspective of face, it is impossible to take everyone to eat a boxed lunch as usual.

When leaving, Cui Wenxue specially slowed down a few steps and came to Chang Haonan's side.

"I really didn't expect that we would have a day when we could convince these Europeans."

He's been working in Ice City before, and he hasn't experienced last year's negotiations, so it's normal to say that.

Chang Haonan also said in a half-joking tone:

"The Italians this time, it can be said that 'I come, I see, I am conquered'......"

Cui Wenwen was stunned for a moment, and immediately realized that this was playing the stalk of Caesar's famous saying, and laughed along.

"Still."

After a short joke, Chang Haonan said with a straight face:

"It must be admitted that in traditional industries, especially in the field of processing and manufacturing, they started too early, and even if we catch up, it is almost impossible to completely make up for the gap in the short term, not to mention the patent barriers."

"So this time, in addition to jointly developing a new type of helicopter, I am also thinking about expanding the scope and depth of cooperation, at least, to bring down several other Italian companies that have come with Agusta!"

His time is quite valuable now, and if he flew to Hokyo just for one thing, it would be too much of a loss.

It's all here, and I can't get some more results.

And as he said to Yan Yongnian two days ago.

The technological blockade can be broken.

Italians may not be as well-known in the field of mechanical engineering as Germany and Switzerland, but in fact they are at a high level and are the second largest in Europe after Germany.

Therefore, it is time to take this opportunity to open a breakthrough in the EU countries.

Cui Wenxue, as the general manager of Bingfei Group, had never thought about it so deeply before.

But Chang Haonan said everything about this, and he must also have a statement:

"That Mr. Chang, the specific situation of the negotiation at that time. I'll keep you informed! ”

(End of chapter)