Chapter 1689 You'd better have a will of steel

Before Liu Yongquan finished speaking, the heavy soundproof door of the control room was pushed open and Qin Xiaoming strode in.

In his hand was a checklist filled with signatures.

He walked straight to Liu Yongquan and stood at attention:

"Report! The SB503 high-altitude test bench is confirmed to be in good condition. The ground inspection, oil filling, sensor calibration, and control system integration of the WS-25 prototype No. 03 have all been completed, meeting the test outline requirements! The test program can be initiated at any time!"

After saying that, he handed the file board in his hand to Liu Yongquan.

The latter took the checklist, carefully read it from beginning to end, and then handed it back to Qin Xiaoming:

"Confirmed. You can start the test!"

"Yes!" Qin Xiaoming took the checklist, turned around and walked quickly towards the central command desk.

Sheng Fei's team had never expected that the test would start so directly, without even a buffer or technical briefing time, and expressions of surprise appeared on their faces.

Lu Chunyan subconsciously raised his head and saw a control panel with flashing indicator lights of various colors around him.

The atmosphere in the entire control room suddenly became tense, leaving only the humming of the equipment fans and the slightly rapid breathing of everyone.

"Attention, control panel!" Qin Xiaoming's voice was clearly heard throughout the control room through the internal communication system. "Activate the SB503 high-altitude platform auxiliary system! Initiate the cold start procedure for the WS-25 prototype No. 03!"

"Assist system activated!"

"Cold transfer program started!"

A series of crisp responses rang out, and huge amounts of energy were injected into the system.

Immediately afterwards, a low, humming sound came from the direction of the test bench. It was the sound of the auxiliary power system and the starting motor working.

On the large central screen, the indicator lights representing the various subsystems of the engine light up one after another.

The identifiers of nearly twenty key components have steadily turned green, indicating that they have passed the self-test and are in normal status.

The information bar next to the large screen began to refresh rapidly, displaying the current flight environment parameters simulated by the SB503 high-altitude platform:

Simulated altitude: 6000 meters

Simulated Mach number: 0.80

And the real-time operating parameters of prototype No. 03:

Bypass ratio: 0.53

Split ratio: 0.9329

Diverter ring angle: +11.6°

Total inlet pressure: 86.29kPa

……

As the oil line was opened and the ignition command was given, the low hum instantly turned into a surging and powerful roar.

The two core curves representing the core engine speed and effective thrust are starting from zero on the trend chart next to them and climbing upward steadily and powerfully.

About half a minute later, the upward momentum of the curve slowed down, and finally settled steadily on two eye-catching green baselines:

Core engine speed: 100% Nc (maximum continuous thrust state)

Effective thrust: 13000kgf

The monitoring data fluctuated very little, showing the engine's excellent stability in subsonic cruise mode (i.e., medium bypass ratio mode).

Liu Yongquan looked at the stable data with a satisfied look on his face:

"In Asian cruise mode, the bypass ratio of the WS-25 actually exceeds that of engines like the D30KP2, allowing it to stably output approximately 13 tons of military thrust in this state... This thrust level is sufficient to support Project , or future sixth-generation aircraft designs, in supersonic cruise."

He paused, with a hint of pride in his tone:

"Since the thrust in Asian Cruise mode is already sufficient, we eliminated the afterburner function in this mode during the design process to simplify the combustion system and improve the engine's service life and overall reliability in the main cruise conditions."

Lu Chunyan did not reply, his eyes fixed on the dazzling and heart-stirring number "13000kgf".

After a long while, he sighed leisurely, "Although I knew this data when I looked at the indicator file before, seeing it running stably here with my own eyes... I still find it a little hard to believe."

Lu Chunyan's career began with Project 82, and he gradually rose to management positions in Project 11. Therefore, he was deeply impressed by that batch of aero engines at the turn of the century.

Now, the military thrust of this WS-25 has exceeded the level of AL31F after turning on the afterburner.

While the two were talking, all the data in the Asian Tour mode had been running stably and completed the recording of the scheduled time period.

Qin Xiaoming's voice sounded again:

"Attention, control panel, prepare to switch to low bypass ratio turbofan mode (supercruise mode)!"

"Understood! Switch to low bypass ratio mode!" The operator quickly repeated the instructions and at the same time moved the corresponding mode selection valve control lever on the control panel neatly.

In the surveillance footage, there was no visible change in prototype No. 03.

However, the roar of the engine entering the control room quickly became sharper.

The real-time monitoring data on the central large screen began to fluctuate violently, like the surface of water after a stone was thrown into it:

The simulation parameters of the SB503 high-altitude platform began to change:

Simulated altitude: 15000 meters (climbing...)

Simulated Mach number: 1.60 (accelerating...)

The changes in the engine's own parameters are more obvious:

The angle of the diverter ring can be quickly adjusted from +11.6° to +6.4°;

The split ratio increased from 0.9329 to 1.0796;

The bypass ratio dropped significantly from 0.53 to 0.27;

The total inlet pressure rose sharply from 86.29 kPa to 202.37 kPa...

As the mode selection valve rotates into place and locks in the position corresponding to the small bypass ratio turbofan mode, the thrust curve shows a brief, small downward fluctuation, as if the engine is adapting to the new "breathing" rhythm.

But this fluctuation did not last long.

Just a few seconds later, the thrust curve rebounded stubbornly and stabilized again at around 13000 kgf.

It is basically the same as the thrust level in Asian Tour mode!

The engine's sharp roar has also settled into a new, higher-pitched note.

"This is one of the core values ​​of variable cycle," Liu Yongquan explained at the right moment. "Although the engine structure inevitably adds some 'dead weight' to achieve mode switching, by dynamically adjusting the bypass ratio and airflow path, the WS-25 can always keep the core engine operating in the relatively optimal and most comfortable operating range, ensuring that the core engine remains highly efficient."

He compared:

"On the other hand, conventional medium-bypass ratio engines, such as the F135, can provide good thrust at subsonic speeds, but once they enter the supersonic region, their performance will rapidly decline due to issues such as inlet matching and core engine load."

Of course, Lu Chunyan is also very clear about these principles.

It would be more accurate to say that Liu Yongquan was showing off rather than explaining.

After all, although the new diverter ring design was developed with the help of Chang Haonan, the overall structure of the entire engine was still created by him.

As Liu Yongquan finished speaking, Qin Xiaoming decisively issued a new order:

"Start the afterburner!"

"Afterburner on!"

The instructions were executed promptly.

"boom--!"

A dull yet explosive roar suddenly erupted! Outside the observation window, a blazing, bright afterburner flame suddenly erupted from the tail nozzle of Prototype 03, its length and brightness far exceeding that of the previous one.

The thrust curve on the central large screen suddenly soared upwards as if it had been injected with a shot of adrenaline!

After fluctuating violently, the value finally stabilized at around 17800 kgf.

Even through the monitoring system, the surging thrust seems to be able to hit you in the face.

Liu Yongquan continued, "Nearly 18 tons of effective thrust is more than enough to propel the aircraft to any speed below the 'thermal barrier.' However, due to the fundamental principles of turbofan engines, when speeds exceed Mach 2.2, the relative velocity of the fan blade tips approaches or even exceeds the speed of sound, generating intense shock waves and frictional heat. This drastically shortens the aircraft's operating life and significantly reduces fuel consumption."

"So, when our sixth-generation aircraft needs to maintain high-speed flight above Mach 2.0 for a long time, we must completely 'abandon' the first two stages of fans and allow the engine to enter pure turbojet mode (high-speed mode), getting rid of this high-speed burden!"

As if echoing Liu Yongquan's words, Qin Xiaoming issued another order:

"Attention, Control Panel! Prepare to switch to turbojet mode!"

"Understood! Switch to turbojet mode!"

The operator's response was a little nervous, but he still firmly flipped the last two key lever switches.

This time, the changes are drastic and intuitive!

The simulation parameters of the SB503 high-altitude platform have increased again:

Simulated altitude: 22000 meters

Simulated Mach number: 2.40

The engine also began to undergo visible changes:

The blades of the first two stages of fans are braked and stop rotating, and are adjusted to a "windmill" posture that is almost completely downstream and has minimal resistance through a variable curvature mechanism.

The diversion ratio jumped from 1.0796 to 3.0800, which means that most of the airflow is forced to pass through the core engine and the outer duct is almost closed.

The angle of the diversion ring shrinks sharply from +6.4° to -31.8°.

The total inlet pressure further climbed to 255.31 kPa.

As this series of parameters changed dramatically, everyone in the control room felt their hearts in their throats.

They had been stuck at this last step several times before.

Lu Chunyan, Peng Weijun and even all the engineers at the Aerospace Engineering Institute who had experienced many failed tests before, couldn't help but hold their breath.

it has started!

The moment the command was given, the thrust curve suddenly dived down like a roller coaster.

15500kgf...15000kgf...14500kgf...The speed curve also showed obvious fluctuations.

The readings of several pressure pulsation sensors monitoring the high-pressure compressor inlet and the mode selector valve throat also began to jump violently...

20 seconds!

These short 20 seconds felt as long as a century.

Fortunately, this time, the fluctuation of the data curve did not diverge, but stabilized again.

After the thrust curve dived to a low of about 14200 kgf, the downward momentum was finally curbed.

30 seconds!

The thrust curve stopped its violent oscillations and stabilized on a new platform:

Effective thrust: 15500kgf!

Although it is slightly lower than the afterburner thrust in low bypass ratio turbofan mode (17800kgf), it is indeed stable!

Moreover, throughout the thrilling switching and stabilization process, the complex three-dimensional cross-sectional structure diagram on the central large screen always maintained a reassuring green color.

It worked!

The entire control room froze for a moment.

The huge rock that had been weighing on my heart for the past few months and the frustration brought by countless failures were swept away by ecstasy at this moment!

Lu Chunyan's wide-open eyes were filled with extreme shock and disbelief.

He seemed to have forgotten to breathe, and just stared at the thrust value on the big screen that was stable at 15500 kgf, and the peaceful green status indicator.

After several seconds, he seemed to have regained his voice. With a trembling voice, almost like a dream, he asked in disbelief, "Lao Liu... this... this... was successful? Really... it worked?"

Liu Yongquan opened his mouth to answer, but in the end he didn't say anything. Instead, he looked at Qin Xiaoming behind him.

"Mode conversion complete! Turbojet mode is operating stably! Parameters are all within the safety envelope! Switch successful!"

Qin Xiaoming's voice, with great excitement yet forced restraint and professionalism, resounded clearly throughout the control room through the microphone, putting the final stamp of confirmation on this thrilling test.

Cheers and applause finally broke out.

"call--"

Lu Chunyan let out a long sigh.

The sixth-generation aircraft is really going to be completed.

Looking back 22 years ago, when the F made its maiden flight, China had not yet figured out how to make a second-generation and a half fighter jet.

And now, mankind's first sixth-generation fighter, combined with the first variable cycle engine, is about to take off in Shengjing.

The situation has reversed 180 degrees.

"This time, I hope you will also have a will of steel..."

Lu Chunyan looked at the direction where the sun was setting and muttered to himself.