The Military-industrial Scientific Research System of the Academic Master Chapter 546

Chapter 546 I come, I see, I am conquered...

Colombo felt that the sentence structure of Gambelli's sentence was a bit strange, but because his main attention was on the sky, he didn't think too much about it. He just shook his head and said in a determined tone:

“I have been in contact with the Chinese people since two years ago, when I was still at AgustaWestland. It was also here, but the object of our cooperation at that time was a propeller-driven passenger aircraft, like the ATR72.”

“I'm sure they didn't have such a high level of technology at that time.”

Gambelli looked over with some confusion:

“MA60, I know, it is our company's first fixed-wing product, but if their technical level was not up to par at the time, why should we choose to cooperate?”

As an engineer who specializes in the helicopter field, he can only have a vague understanding of the company's newly established fixed-wing business unit.

　　Specifically, after making sure that the other party's existence would not affect one's own status and the resources obtained, he stopped paying much attention to it.

“The situation is similar to this aircraft. Although everything else is average, its core competitiveness is very strong. It can save about 8% of fuel compared with passenger aircraft of the same class. This is what many airlines dream of.”

 Colombo also lowered his head again as he spoke and rubbed his sore neck:

 “Furthermore, their technological progress is very rapid.”

“When I first came to China, when I saw the MA60, it looked very crude, with a lot of shadows of the Soviet An-24 transport aircraft on it.”

"But only half a year later, the other aircraft was completely different. In addition to the fuel economy card, they also installed new propellers and flight control systems, which reduced the noise in the cabin to the average vortex level. Fan airliner level.”

Chang Haonan directly stretched out his hand, signaling Gambelli to do whatever he wanted.

About five minutes later, Gambelli got out of the cabin again, sweating all over in the early spring.

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

 The overall decibel level does not change much, but annoying pulsing sounds are almost completely eliminated.

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

 The results of the instruments were similar to what his ears heard.

Thinking of this, Gambelli rubbed his hands almost involuntarily, showing an eager expression.

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

The Dolphin's ducted tail rotor is even safer.

 But emotionally, it was still difficult for him to convince himself.

 For the former, he relied on the good relationship he achieved with Huaxia during this project to promote higher-level cooperation between the two parties in the future, and he also got a wife by the way.

 Gambelli once again heightened the importance of this cooperation in his mind.

Achieving active noise reduction by adjusting the phase difference of the propeller sounds simple in principle, but anyone with experience in engineering control knows that theory and practice are two different things.

 The final result is that this helicopter feels more like a small business jet when working.

 This will be more comfortable for passengers inside the cabin.

Therefore, after the helicopter stopped and before the pilot shut down the engine, Gambelli quickly ran to Cui Wenxue and Chang Haonan not far away and asked if he could go to a nearby place while the aircraft was in working condition. have a look.

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

“In other words, that's when they started researching propeller noise reduction technology?”

Most of the noise falls within the higher range of human hearing, which is the sound of the turbine engine itself.

 It is another matter if it is really implemented.

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

Helicopters are different from passenger planes. Normal working conditions include loading and unloading cargo or personnel during the engine startup process. Therefore, except for the vicinity of the tail rotor, there are no generally prohibited safety zones around the aircraft.

 But both from Colombo's personal perspective and from AgustaWestland's perspective, it now seems that the bet has been won.

Gambelli opened his mouth, but no words came out.

Regarding the latter, the MA60, as a new model provided by a new supplier, has already received a total of more than 20 orders from Thailand and China without completing the finalization and certification process. Obviously, it is also a promising future. .

 This is a bit embarrassing to say.

For people outside the cabin, the propagation distance of high-frequency noise is closer, which will also reduce the impact of low-flying helicopters on people on the ground.

 And they actually developed another method of reducing noise from noise sources at almost the same time.

  If he came here, his main idea was the same as before when he faced Bell Company or Westland Company, which was to simply find a benefactor to share the risk.

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

 Mainly because I really don't know what to say.

However, Colombo shook his head decisively:

"That's not true. The MA60's noise reduction principle is to control the phase difference between the left and right propellers so that the mid- and low-frequency noises they emit cancel each other out. It is equivalent to some kind of active noise reduction measure, and it is only effective inside the cabin. Listening outside It's still noisy.”

Cui Wenxue can still figure out who is really in charge of this round of cooperation.

If I could replicate the successful experience in the helicopter field...

 But Gambelli really couldn't understand it.

 The Zhi-9WY prototype quickly completed its scheduled two circles around the field and landed again on the tarmac.

“So this time, we must have worked **** noise sources such as the rotor and the fuselage.”

 Intellectually, Gambelli already fully understands the value that this technology can bring.

The latter was not polite. He opened the cabin door skillfully, took out a noise-testing device from his bag, and got in alone.

“But helicopters with a normal structure obviously do not have this possibility. The main rotor and tail rotor are hard coupled through the transmission mechanism, and there is no way to adjust the phase difference. Moreover, their noise levels are not at the same level and cannot be offset.”

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

 The previous investment in MA60 was undoubtedly a gamble.

 Why Chinese?

 He has no prejudice against any country, but this is really not in line with scientific laws.

The Chinese have had almost no achievements worth mentioning in the helicopter field before.

 Now come up and directly dump Wang Zha?

“Will this low-noise propeller have any problems with aerodynamic efficiency?”

Gambelli asked this question with extremely complicated emotions.

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

On the one hand, he hopes that the opponent's technology will show some shortcomings in at least some other aspects, because this means a "trade-off" rather than an all-round crushing.

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

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

“Show Dr. Gambelli the aircraft's technical manual.”

Soon, a bilingual material in Chinese and English that had been prepared was handed over to Gambelli.

There is even a murderous and heart-wrenching comparison between it and the original dolphin.

The data is so detailed that it even includes engine output power curves.

Of course, this is not a temporary production recently, but was used as a promotional material when I participated in the Singapore Air Show.

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

 Just compared it with the naked eye with the AS365N1 next to it, and then signed and placed the order.

　　It directly staged a drama that was forced to death by a fan—

 Although the workmanship and lifespan are indeed a bit worse, it has more functions (armed), better performance (long hover time), and is cheaper.

 What kind of bicycle do you want?

As a professional in the field of helicopter design, Gambelli naturally found the key data directly.

 The results are obvious.

While the rotor itself did suffer some impact, the redesigned transmission system allowed more engine power to be efficiently delivered to the rotor end.

 In comparison, the efficiency reduction of about 3% is nothing to mention.

 It's okay even to be regarded as a test error.

As an aerospace engineer, Gambelli can certainly see the correlation between these data, and he is definitely not just writing it casually to deceive people.

Furthermore, the test flight just now cannot be fake...

 “Unbelievable…”

 “How on earth did you do it?”

Gambelli asked directly to Chang Haonan behind him.

This time he also saw that Cui Wenxue was not the one who could really make the decision in this cooperation.

 It was this young man who had been standing nearby inconspicuously before.

"In general, the flow field characteristics of the rotor and fuselage assembly during flight are first calculated, and the focus is on capturing the shock waves and blade tip vortices, because when the rotor vibrates to emit pulse sounds, these two will also be induced. This flow state is then integrated to obtain the far-field sound pressure characteristics, and the sound field patterns generated by main rotors of different shapes and specifications can be calculated relatively accurately..."

“As for the more specific technical details here, our engineers from Torch Group and Bingfei Group will provide more detailed explanations after the cooperation between our two parties is reached.”

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

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

Gambelli also knew that it was impossible to extract someone else's core technology here, so he turned to a more theoretical question:

“Relying on CFD calculations? How do you ensure the calculation accuracy of unstructured grids?”

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

"What I mean is that the finite volume method (FVM) can usually only achieve second-order effective accuracy in the field of compressible fluids. In the past, it was definitely enough to just calculate the aerodynamic efficiency, but if you calculate the sound field according to your idea, The error must be huge.”

“We do not use FVM for CFD calculations, because it is theoretically impossible for FVM to achieve high-precision numerical formats for unstructured grids.”

Chang Haonan replied with a smile.

While the two were talking, members of the Italian delegation who had just retreated to a distance gradually gathered around.

Hence, he raised his voice slightly to ensure that others besides Gambelli could hear.

“In terms of high-precision finite element calculations, there are some specialized techniques used to solve problems such as numerical oscillations or windward physical properties, so calculation accuracy and calculation 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 slightly and glanced at the circle of Italians around him.

 Sure enough, the expressions in several of them's eyes changed immediately.

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

 The words just mentioned were addressed to this group of people.

 The group stayed in the outfield until lunch time.

 When there are foreign guests, even from the perspective of face, it is impossible to take everyone to eat lunch as usual.

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

“I never thought that one day we would be able to convince these Europeans.”

  He has been working in Bingcheng before and has not experienced the negotiation last year, so it is normal to say this.

Chang Haonan also said in a half-joking tone:

“This time the Italians can say, 'I come, I see, I am conquered'…”

 Cui Wenxue was stunned for a moment, and then he realized that this was a reference to Caesar's famous quote, and he also started laughing.

"but."

 After the brief joke, Chang Haonan said seriously:

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

“So this time, in addition to jointly developing a new model of helicopter, I am also considering expanding the scope and depth of cooperation, at least to attract several other Italian companies that came with Agusta!”

His time is quite valuable now. It would be a waste if he flew to Haojing just for one thing.

Even though we are here, we still need to produce more results.

 Just as he said to Yan Yongnian two days ago.

 Technological blockade can be broken.

The Italians may not be as well-known as Germany and Switzerland in the field of machinery manufacturing, but in fact the level is very high and the scale is second only to Germany in Europe.

 Hence, we can take this opportunity to open a breakthrough among EU countries.

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

But since Chang Haonan was talking about this, he definitely had to express his position:

"Mr. Chang, I will report to you the details of the negotiations at that time!"

 (End of this chapter)

Chapter end