The sound of a gas turbine engine is quite unique, as the turbine fan blades rotate and the heat dissipation holes that dot the surface of the monocrystalline fan blades produce a sound similar to the rapid blowing of thousands of miniature whistles at once.

At this time, in the power laboratory, although the beeping still clearly clenched everyone's ears, it was not as harsh as expected. It was as if the air had been cut by many sharp blades, and in the midst of the hurry, there was a hint of gentleness.

"It's ...... The sound of a gas turbine engine? Even if it's a slow car idling, it's too low, isn't it? Is it because the engine is small?"

"No! I have seen the improvement test of the Kitayama OP-076 small turbojet engine used by our military target aircraft, because the layout of the small gas turbine engine is compact, the fan blade area is small, the heat dissipation holes required are relatively large, and the noise is very high......! It's different!"

When the voice of Tianxing I sounded, everyone present immediately drew their attention from Li Fanyu's body, and their professional habits for many years made them quickly discover the difference of this model aircraft engine that they called "model aircraft".

Wang Rui, who has been following Li Fanyu, couldn't help but be secretly happy when he saw everyone's reaction - a group of old hats!

What kind of thing is Beishan? It's just a target engine for testing interceptor missiles, a one-time thing, can it be compared to our Tianxing I?

As an expert in kinetics and thermodynamics, Mei Yishu frowned directly when he heard Tianxing I's voice and hissed softly.

However, given that the current Tianxing I had just been running-in, he just pricked up his ears and continued to listen carefully.

Li Fanyu was not in the mood to continue arguing with them, took a deep look at everyone, and then turned around and walked to the test bench data display board located in the corner of the laboratory.

The engine that runs for the first time after assembly, like the Tianxing I, cannot directly drive the full horsepower after starting. In order to fully test the engine, it is necessary to run according to the prescribed procedures, on the basis of structural transmission and heat transfer analysis, to run in, slow down and then gradually increase the rpm to the maximum power.

There are many kinds of run-in procedures. But because Li Fanyu had high expectations for Tianxing I, he directly used the most brutal run-in method, that is, the way of speed advancing and retreating one.

Put it on the car, it is roughly the concept of two feet of accelerator and one foot of brake,

This run-in method is the best way to check the gap between the rotor and stator of the engine. Generally speaking, when carrying out such a test run-in, if the gap is too large, it is very likely to make a sound of "rub rub!" and "forehead ......".

But now, with the interference of the program, the sound made by Tianxing I is particularly comfortable.

"Dirty!"

"Hmmm......"

……

"Dirty!"

"Hmmm......"

This sound can only say two things - the layout inside the engine is extremely compact. And...... The tremor between the mechanical parts of the engine is greatly suppressed because of the high precision of the sufficiently high coefficient!

However, as the run-in slowly ends, the engine and enters the slow train stage, the exclusive increase and the noise is still much smaller than that of the general aviation engine, in the ears of a group of experts, there is something else!

"What is the structure of the turbine blade fan? What form of linkage shaft is used? How can the noise be so small?!"

That's the problem with Mei's book.

Obviously, under the tips of this expert of the great fighter, many people have realized the key.

Hearing this question, Li Fanyu couldn't help but glance at him more. Xin said that although the old man's character may be a little problematic, he is still professional enough.

In the spirit of academic exchange, he decided to solve their doubts;

"The blades of Tianxing I are not perforated. Therefore, the noise is 25% less than that of the same type of monocrystalline fan blade. Three-axis linkage, the main push turbofan, high-pressure turbine fan group and low-pressure turbofan group coaxial different rotation. Moreover, the thirteen groups of turbofans of the low-pressure turbofan group can coordinate the J-type combustion chamber duct in a mechanically matched way with the operating room market at different speeds. ”

"How is that possible!" On the spot, an engineer on the fly exclaimed: "I can understand the coaxial different speed, even if your thirteen groups of low-pressure turbofans can match the high-pressure duct by themselves, it is nothing more than to reduce the noise in the slow state, expand the speed range to maintain the temperature of the combustion chamber, and reach the working state as soon as possible." But how long can the turbofan last if there are no heat dissipation holes on it? At a working temperature of one or two thousand degrees Celsius, without heat dissipation holes, you don't know if this thing is going to melt and deform in the sky?"

Huang Haixing deeply agrees with this, "The turbofan is not perforated, first of all, it is a problem of heat dissipation. If the heat dissipation performance is not good, the life of the turbofan will be drastically shortened. Also, I'll assume that your thing doesn't deform at temperatures of more than 1,000 degrees Celsius. The weight can't go down, and the speed can't go up. How much do you want to achieve this engine thrust-to-weight ratio? 1 to 5 or 1 to 4?"

Looking at the engineer who seemed to have been stepped on by his tail, and Huang Haixing, who pretended to be forced lightly, Li Fan was foolish: "Who told you that the turbofan has to be punched?"

"Also, the operating temperature is more than 1,000 degrees...... Is it high?"

Huang Haixing blinked, "Isn't it high?"

"Ha!" Li Fanyu snorted and patted Wang Rui's chest with his backhand, "You introduce to Mr. Huang, what is the working temperature of the brake disc on the red foot brake system used on our Xcar supercar and FE car." ”

"The average braking is 320 times in a race, and the peak temperature is 2,100 degrees Celsius. Wang Rui, as the chief technical engineer of Zhengxin Racing Team, gave the answer directly.

"How can you compare a brake pad with a turbo fan blade! Can that be the same? The turbine fan blade is rotating all the time!"

"So!" Li Fanyu spread his hands, "Tianxing I has given up the traditional single crystal blade and adopted a lighter, thinner, and better heat dissipation composite ceramic alloy + carbon fiber sandwich structure. There are no holes in the surface, but ...... Inside each blade fan, there are 800 through-type heat dissipation ducts! Compared with the fan blades you asked me to manufacture, this one has a 30% increase in strength per unit volume, a 20% reduction in weight, and the heat dissipation is basically the same. ”

"As for the thrust-to-weight ratio, one-to-five, one-to-four, ......? I'm afraid you're not here to scold people. This is a gas turbine engine! Not a piston engine! With such a low thrust-to-weight ratio, why should I do it? How good would it be to just install our 16?"

As he spoke, the Tianxing I on the bench had finished the slow train state, and with the regulation of the test program, the work peak began to climb.

In the laboratory, the beeping gradually increased, and Tianxing I finally got rid of its gentle side and became manic.

As the thick and sturdy test bench gradually creaked, several sets of data on the test data panel in front of Li Fanyu and others were also being refreshed rapidly!