After making sure that everyone had entered the test control room, Kang Chi finally nodded to Yan Hui.

The first round of ground tests of the turbofan-30 engine began.

In this round of testing, the main thing is to let the engine, simulate the operating conditions of the engine under ground conditions.

After the completion of the first round of testing, it will also be transferred to a special outdoor site for the second round of testing in special climates and conditions such as rain, freezing, high temperature, sand and dust, bird impact, smoke swallowing, etc.

For example, in the water swallowing test, in order to simulate the working state of the engine in weather such as water vapor, clouds, fog, rain, snow and hail, there will be a special water spray device in front of the engine, and then in the case of the engine running, several tons of water will be sprayed in just a few minutes, and the engine will not be turned off to be qualified.

However, this test method is usually only for jets and engines, and for tiltrotors such as Yinhe, especially electric aircraft, this extreme simulation is not very useful......

If it is fixed on the bench, in addition to measuring the impact of foreign objects on the propeller, it is of little significance to test the impact of foreign objects on the propeller, and the reference value of other tests is not large.

After the end of the second round, special high-altitude simulation test equipment will be used to carry out high-altitude bench testing, which is specially used to test the 'wind tunnel' of the aviation engine, which can simulate various environments of the engine flying at high altitude, such as different air pressure, air velocity, air flow angle, temperature, etc.

In this simulated environment, more complex tests such as thrust transients, intake distortion-induced surge, high-altitude thrust, fuel consumption, in-flight envelope ignition, and stable combustion can be performed.

However, the high-altitude simulation platform is more difficult to build than the wind tunnel, and there are only two in the country, and the first SB101 took 30 years to build, which is enough to see the preciousness of its resources.

Therefore, it is generally not necessary to build an aerial engine casually, and send it directly to the high-altitude platform, at least after passing the initial ground simulation test before the third round of high-altitude bench test.

According to statistics, the development cost of an aircraft engine only accounts for 10% of the design, 40% of the manufacturing, and 50% of the test.

Although Kangchi is very confident in the engine he builds, this link is essential, otherwise no one would dare to use his engine......

"The departments are in place, the first round of testing, and the cold operation begins."

As Kangchi gave the order, an engineer decisively pressed the button.

At this time, the simulation is only about starting the engine, starting the oil filling and other preparations, and after about two minutes, after confirming that everything is normal, Kangchi continues: "Start the slow car test." ”

"Start slow test, engine ignition!"

As the test engineer pressed the ignition button, the engine inside finally started running, and even through a wall, everyone could still hear a sharp engine sound, and the atmosphere gradually became warmer.

The slow train test mainly simulates the warm-up after the engine starts, the ground taxiing, and the final approach and landing phases.

In this state, the engine is basically controlled at the lowest speed.

Wind tunnels are also just blowing at the lowest possible power and maintaining basic air circulation.

It is worth mentioning that the wind tunnel usually does not work for a long time, because the wind tunnel works by compressing the air into a canister, once the air is gone, and the air has to be recompressed to continue the next round of testing.

And how long it can be left depends entirely on how fast you want to blow the wind.

In terms of the performance of this wind tunnel at the Eagle base, the wind blowing at Mach 10 can only last for 3 seconds, and Mach 1 can last for 30 seconds.

Like Huairou's JF-22, the wind blowing Mach 33 only lasts 100-300ms.

After all, Mach 33 is too fast, this speed can cross the Pacific Ocean in 14 minutes, if you want to build a wind tunnel that can blow Mach 33 in 14 minutes......

Almost impossible!

Think about how much air you have to stockpile?

Hoarding air also burns money!

Many cars are sent to the wind tunnel for wind resistance testing, and when the wind blows a few hundred yards, it is said that it is a thousand taels of gold when the wind tunnel sounds, not to mention that the plane blows a few Mach winds......

However, the turbofan 30 is not an engine designed for supersonic aircraft, and a maximum of Mach 1 is enough, so it can greatly save the time and cost of the entire testing process.

"The slow train test was completed, the blades were running stably, the engine temperature was normal, and no special vibrations were found."

"Roger, ready for takeoff."

After the slightly boring slow train session, the most anticipated take-off test is the one, in which the engine power is gradually increased until it is designed to reach its maximum power.

"Take-off state simulation, power 5 seconds to start ......"

As the test crew began to slowly push a throttle lever similar to that in the cockpit of an airplane, the engine in the test room suddenly began to get louder and louder, and the air flow in the wind tunnel slowly accelerated.

It wasn't until the acceleration to Mach 0.2 that everyone heard the sharpness of the engine sound suddenly increased by a level, and the thrust curve that rose sharply on the big screen was about to enter the valley slope and slow down, but after this screeching sound, it suddenly began to rise sharply again......

What's the situation?

When Dong Jun's eyes quickly shifted from the data screen to the live engine screen, he was immediately stunned.

I saw that the tail of the so-called 'large bypass engine' actually spewed out an obvious red flame tail!

This is......

Variable cycle afterburner?!

Just kidding, right?

At this moment, he finally believed that this engine, which was one lap smaller than the turbofan 20, was theoretically possible to burst out with a thrust three times higher than that of the turbofan 20......

Because this is a special dimensionality reduction blow!

After opening the afterburner, the turbofan engine is actually no longer divided into internal and external ducts, it is more like a turbojet engine, at least in terms of space utilization, the performance of the entire engine is brought into full play.

However, afterburner technology is usually only used in engines with small bypass ratios that pursue extreme performance.

No one has ever used this technology for engines with large bypass ratios......

It's like installing a nitrogen accelerator on a performance car in a truck or family car......

This isn't a dimensionality reduction attack.

And this thing is not the same as a car with a nitrogen accelerator, the afterburner is part of the engine, so it is completely a redesign of the engine, whether it is the difficulty of design or manufacturing, it is not at the same level at all.

Even if you install a nitrogen accelerator device on the truck, you have to consider whether the strength of the truck's body, balance, tires and other things can be tolerated, not to mention the aircraft engine, which is a hundred times more complicated.

So most likely, this is simply not achievable with existing materials.

"The take-off simulation is over, the maximum thrust of the bench during take-off is 49.52KN, and the 30S continuous maximum power state test continues!"

“491.3KN！？”

"It's amazing, it has reached 50 tons of thrust!"

“……”

Looking at the thrust graph on the screen, everyone was immediately excited.

KN is a more professional expression unit in the field of aviation power, if replaced by kilogram force that is easier for ordinary people to understand, 491.3KN is equivalent to 50098Kgf (1,000N = 101.971621 kilogram force), which is exactly 50.09 tons of thrust.

Even the two leaders, who have always behaved calmly, couldn't help but be a little moved after seeing this data.

Regardless of whether Kangchi has added the afterburner technology, whether there is any suspicion of cheating, this achievement alone has completely broken the record of all aero engines in Huaguo.

However, although everyone was excited, because the test was still in progress, everyone quickly restrained their emotions and stared at the thrust graph.

After all, in past engine tests, there are also some engines that have achieved amazing results, but suddenly have an accident in the next second, so that the prototype is scrapped directly......

However, in the following 30 seconds of continuous maximum power testing, the thrust curve of the engine also remained very stable, which made everyone breathe a sigh of relief.

"The continuous maximum power state test was completed, the engine operation status was normal, the temperature was normal, the gas pressure pulsation in the afterburner return area was normal, and no shock combustion phenomenon was found."

After thirty seconds, the engine power begins to slowly decrease, and then it is time for the relatively boring finishing steps such as slowing down, parking, and cooling.

"Mr. Kang, the first round of testing was successfully completed, and this is specific data analysis."

Not long after the finishing steps were over, Yan Hui handed the freshly printed data to Kangchi.

"Everyone rests for ten minutes and then prepares for the second round of testing."

"Okay."

Although Kangchi said that he was resting for ten minutes, everyone had no idea about resting at the moment, and they began to discuss the test just now.

As the engine design supervisor of the Yun-20, Chi Jinliang couldn't help but come directly to Kangchi and asked: "How did you do it by using afterburner technology on the large ducted engine?" ”

"And the length of this engine looks like it's less than 7 meters...... It doesn't look like an engine with an afterburner. ”

Dong Jun couldn't help but add: "Are you sure this is a large bypass engine?" ”

Kangchi smiled and directly pulled out a design drawing of the engine: "The bypass ratio is 6:1, which is definitely a large bypass engine." ”

"It's less than seven meters long, and that's because I moved the afterburner forward to the section of the connotation road combustion chamber, which is a turbojet design with two combustion chambers."

The two of them were stunned when they heard this.

Move the afterburner forward to the zone of the combustion chamber of the connotation road?!

Isn't this the connotation of the Tao on the fire?!

"This ...... The design life of your engine ...... How many hours are there? ”

"Twenty thousand."

"It can't be!" Chi Jinliang immediately exclaimed, "Your connotation Dao will definitely not last a thousand, no...... 100 hours and it will be scrapped! ”

Because of the excitement, he didn't even control the volume, and suddenly attracted everyone's attention.

In the face of this question, Kangchi just pulled out a pile of information without changing his face: "How do you know that it won't last for a hundred hours?" Why don't you take a look at this first? ”

[A new structural ceramic material composed of Al203, ZrO3, C-BN, Si3N4, Sic and other materials with high temperature resistance, high strength and corrosion resistance - PG01]

After seeing this title, Ji Jinliang's expression was stunned for a moment, and then he hurriedly read it carefully, and then the hands holding the documents began to tremble......

Density 1.06g/cm3,

Tensile strength 300kgf/mm2,

The fracture toughness is up to 600kgf/mm

The maximum withstand temperature is 4600°C,

……

Looking at these data, which completely crushed the existing aero engine materials, some of which were even directly doubled, Chi Jinliang's brain suddenly went blank.

How is this possible!?

But......

The facts seem to be in front of you.

Otherwise, how is it possible to add afterburner to an engine that is no more than seven meters?

If there is no afterburner, how can an engine, including an engine with a shell diameter of only 4.4 meters, burst out with 50 tons of thrust?

So the most eye-catching thing about the Kangchi engine is actually not the engine itself.

It's this material that completely breaks the bottleneck of engine development!

What the hell,

What kind of monster is it?

Chi Jinliang returned the information to Kang Chi in a daze, and then silently walked to the corner, found a chair and sat down.

At this moment, he just wanted to be quiet......

Seeing that Chi Jinliang was so hit by Kang Chi that he was about to shut himself up, Dong Jun couldn't help but feel powerless.

But soon, a question came to his mind.

Fifty tons of thrust, which was achieved with the afterburner turned on,

And the engine in this state, although the thrust is large, but it is very fuel-intensive, so it is impossible to turn on all the time.

Otherwise, the range will drop sharply, and there will be no practical value.

It is precisely because of the problem of fuel consumption that turbojet engines have basically been eliminated since the fourth generation of fighters.

"If the afterburner is turned off, how much thrust can it have while cruising?"

Dude's problem angle is very tricky.

Kang Chi replied with a slightly mysterious smile: "Don't worry, isn't the test not over yet." ”

Of course he knew what Dong Jun was thinking in his head.

If the thrust is not enough when the afterburner is turned off, the cruising speed of the aircraft will be very slow, and if you want to increase the cruising speed, you will have to increase the power of the engine, which will also be very fuel-intensive.

Therefore, if you change from four engines to two, it may become a small horse-drawn cart, and maybe the range will be lower.

Although this increased maximum thrust can also increase the load capacity and reduce the take-off distance, it is also very limited.

At this time, the variable bypass ratio can play a huge role.

Seeing that Kang Chi was a little pretentious, Dong Jun suppressed his curiosity and quietly waited for the next test.

After about an hour, the preparations for the second test were finally completed.

"All departments are in place and ready to start the first round of testing the 8th project, the variable duct cruise test!"

Change...... Changing the duct!?

Dong Jun's eyes widened suddenly.

In the discussion just now, Chief Shen and Chief Lu were just beside them, quietly listening to their technical discussions, and they could neither interject nor need to interject on this kind of technical issue.

Anyway, through a few words that you can understand, you can also get a general idea of the situation.

But when they heard the name of this round of tests reported by Kangchi, the two bigwigs couldn't calm down anymore.

"Changing the duct...... You engine...... It can also be ducted!? ”

Although Chief Shen was trying his best to maintain his steadyness, his somewhat trembling voice could not hide the excitement and shock in his heart at this time.

For a long time, variable duct technology has only existed in theory, and no one in the world has ever heard of anyone who can build such an engine.

But Kangchi suddenly said to them: Our next test is to change the duct.

This surprise is too big, isn't it?

Or just kidding?

"That's right, the turbofan-30 is actually a variable-culvert engine with a bypass ratio of 6-10!"

(End of chapter)