Chapter 438 A milestone in China’s civil aviation industry!

Within a few minutes, the plane entered the runway smoothly from the taxiway, then gradually accelerated, raised its head, and took off...

Except for the slight discomfort during the climb, until entering level flight, Jonjit did not feel the sharp noise in his memory that made his eardrums burst.

Of course, the low roar is unavoidable, but in terms of intuitive experience, it is more than half better.

"Is the cabin soundproofed well?"

Naturally, his first thought was to lean over and touch the inner wall of the cabin next to him.

Naturally, it is impossible to figure it out.

No matter what black technology is used on the aircraft body, it must be placed in the outer hard shell or the middle layer. The internal bushings, including the inner porthole glass, are even classified into the category of "decorative materials" in many cases.

"Mr. Jungjit, our flight experience was not bad, right?"

Gao Quan saw Qiongjit's novel reaction as if Grandma Liu had entered the Grand View Garden, and knew that the latter was shocked by the noise level in the cabin.

In fact, even he thought there was something wrong with his hearing during the first test flight of the MA-60 No. 03 full-state prototype...

The Yun-7 aircraft was originally produced in Haojing. Before he was transferred to an administrative position, he was responsible for some technical work of this model, and he often flew on the old Yun-7 when he was on business trips. Naturally, he knew this. What will it be like when a normal turboprop airliner is flying, especially when the engine is at full output during takeoff and climb.

However, even though he was standing not far outside the wing at that time, he did not feel the extremely uncomfortable roar.

"Ah...this...is really good."

Jonjit also realized that her performance just now was a bit embarrassing, and quickly returned to her original state, but after a few seconds, she still couldn't help her curiosity and asked:

"Did you use any special sound insulation materials on the fuselage of the aircraft?"

Gao Quan, who finally waited for this question, certainly understood what the other party was worried about.

As a representative of the airline, although he was surprised by the quietness of the aircraft, if he had to choose between cost and cost, he would choose the latter without hesitation.

All costs will eventually be passed on to passengers.

Those who will take regional airlines like them are price-sensitive customers, and they are absolutely impossible to accept a fare increase for the comfort of a one-and-a-half-hour journey.

Therefore, his first words dispelled Jungjit's concerns.

"In terms of fuselage structure and materials, like most passenger aircraft around the world, we use ordinary additional honeycomb sandwich structure sound insulation materials, which will not bring additional costs and maintenance difficulties."

The latter was indeed relieved.

Improving comfort without increasing costs is of course a 100% good thing.

Immediately afterwards, Gao Quancai continued to explain:

"For several other typical turboprop airliners on the market, the peak noise in the cabin during level flight, that is, the noise at our current location, is around 80 decibels, and may reach over 85 decibels during takeoff. Considering this data alone, it is actually It is not larger than a passenger plane using a turbofan engine, but the noise frequency of a turboprop engine is wider. It is the mid- and low-frequency parts that can easily cause serious discomfort to the human body. However, general sound insulation materials can only filter high-frequency noise, so passengers The ride experience is very poor.”

"Our aircraft uses a bionic propeller design, combined with some other control methods, which can reduce the noise peak by 2-3 decibels, and focus on reducing the mid-to-low frequencies. As for the effect, I would like to ask Mr. Qiongjit Already experienced it.”

"Creature what?"

The word "bionics" was too outrageous for the Thai translator who was only temporarily pulled over, so it had to be translated into English. However, Reggit was obviously not familiar with such a common noun, but he only understood the first sentence. bio-root word.

"Oh, there is a comb structure similar to owl feathers designed on the outer leading edge of the propeller, which can significantly weaken the fan's broadband noise below 2kHz. If you are interested, you can take a closer look when you get off the plane. Look at our propeller design.”

The design of this comb structure needs to be very delicate, and it also needs to be adapted to the propeller and the engine itself, which is not easy to learn.

And Ridgette is just a professional manager of an airline company.

More importantly, the leading edge of this comb tooth structure will actually affect the efficiency of the propeller, so it cannot be fully optimized according to the quietness requirements. If you just copy a similar one, the overall performance may be counterproductive.

In fact, what really reduced the noise of this aircraft was the part that Gao Quan just vaguely mentioned——

After Chang Haonan developed the logic of active wing flutter control, he quickly began to consider how to extend related ideas to other fields.

As we all know, vibration and noise are essentially the same thing.

Since wing flutter data can be collected and then controlled by actively applying vibrations of different phases, more regular sound waves can naturally be followed accordingly.

That is the logic of active noise reduction.

In fact, 606 has researched similar technologies in the past. They once tried to use active noise control based on speaker arrays on the Yun 7, which is the set found in many luxury cars in later generations. The effect is outstanding and can reduce the noise by an astonishing 13%. -22 decibels.

However, not to mention the sky-high cost of this set of equipment, its weight and power consumption were also quite exaggerated, and would even directly affect the basic performance of the aircraft. In the end, it had to be abandoned.

But Chang Haonan adopted another idea.

Although it is also active noise reduction, he did not install additional audio equipment. Instead, he maintained a certain phase angle difference between the two propellers of the aircraft to mutually reduce the noise of the propeller on the other side.

In fact, the initially completed phase angle control algorithm even included the function of automatically calculating the optimal phase angle difference based on the aircraft's different flight altitudes and speeds, which can achieve optimal noise control under almost all flight conditions.

But the PW127J engine is really holding it back.

It is basically a mechanical hydraulic control logic, and the control accuracy is not even as good as the AL10FN on the J-31.

Fortunately, researchers from the 606 Institute later developed many new tricks for the electronic controller. Although it could only use a fixed synchronization phase angle difference, this advantage was enough compared to other competing products of this era. .

Ridgit's performance just now is the best proof.

……

To demonstrate the aircraft's range, the flight experience lasted nearly four hours.

However, after getting off the plane, Regit didn't feel the tinnitus and dizziness that he was almost accustomed to in the past. At most, he could only feel the fatigue of normal flying.

After the group returned to the car, Regit, who had recovered from the shock just now, was no longer reserved:

"Mr. Gao, we need you to provide a complete quotation and a specific delivery schedule. You know, this is a brand-new aircraft after all."

The technical source of the MA-60 is actually the Y-7. Of course, the aircraft itself has been completely reborn, and the AN-24 has a mediocre international reputation. It is impossible for Haojing to have the brains to publicize the relationship between the two, so the new aircraft Zhou 60 is a brand new model on the market.

Compared with sub-model upgrades such as the ATR72-500, the delivery cycle of new aircraft will undoubtedly cause some concerns.

Especially for an airline as small as Bangkok Airways, missing a peak season business may be the difference between life and death.

"No problem, but we need about two working days to prepare the documents in both languages. During this period, I think we can ask someone from our public relations department to take you around Haojing?"

Gao Quan asked tentatively.

This tour is naturally not a real tour.

Doing business, even a seemingly high-end business like selling airplanes, is inseparable from the down-to-earth part.

In addition to producing excellent products, we still have to work hard in other aspects.

Of course, Regit is definitely not a white lotus. It would be better to say that this is the part he is waiting for.

"Okay, then I will take advantage of this time to deeply experience the history of Chinese civilization..."

On the surface, it is better to speak in a high-sounding way.

Gao Quan, who was sitting in the next row, secretly clenched his fists in excitement.

Although Regit did not express his position clearly, it is obviously a sure thing that things have reached this point.

As long as this deal can be signed, his name Gao Quan will definitely remain in the history of the development of China's aviation industry.

Although this is not the first time China has exported civilian aircraft - Bingcheng Aircraft Company exported two Y-12 transport aircraft to Sri Lanka about ten years ago.

But the meanings of the two things are obviously different.

On the one hand, the Y-12 is, after all, just a small general aviation aircraft, and the qualifications required to operate it are completely different from operating a serious passenger aircraft.

On the other hand, MA60 is also the first model designed, manufactured and approved by China using the new CAAC standards.

It can be called a milestone in China's aviation industry.