You promised to build cars, so why did you go into the military industry?

Chapter 85 Lessons from Others

In less than 10 minutes, Li Ran finished reviewing the papers, stretched a bit, and began his daily patrol.

An hour and a half later, in the engine manufacturing workshop of the planetary-level integrated industrial base, the clean air, with its constant temperature and humidity, was filled with the distinctive smell of lubricating oil and metal.

Lin Yu was staring intently at the display screen of a giant 3D metal printer, his fingers rapidly sliding across the touchpad as he adjusted the parameters.

His anti-static clothing was full of wrinkles, and his eyes were bloodshot.

Looking like that, people would believe it if you said she hadn't slept for three days.

As Li Ran passed through the emergency exit, she saw Lin Yu's familiar yet disheveled figure through the glass curtain wall.

"Huh?" Li Ran picked up the intercom phone on the wall, his voice full of undisguised surprise. "Lin Yu, you didn't even get a break after coming back from the launch site?"

Lin Yu didn't reply, his eyes still fixed on the data flashing on the screen.

Only after the last parameter was adjusted did he let out a long breath and simply replied, "Not tired."

Li Ran didn't ask any more questions.

After putting on his anti-static suit, he pushed open the airtight door and entered the workshop. He stood outside the yellow safety line, crossed his arms, and watched quietly.

Lin Yu wasn't the only one in the workshop.

A dozen engineers are conducting final checks on three engines that have just completed final assembly.

These three engines are about 70% similar in appearance to the ZK-33F that is currently in mass production on the assembly line, but the details are completely different.

The nozzle expansion section has a narrower angle, the layout of the gas generator piping appears to have been completely redesigned, and the reinforcing ribs of the turbopump housing have been repositioned.

Li Ran's gaze swept over the engine and landed on the worktable in the corner of the workshop, which was half-covered by a dust cloth.

Several technical manuals with worn edges were laid out, two of which had the words "Technical Outline of YF-100 High-Pressure Staged Combustion Cycle Engine" and "Summary of YF-115 Upper Stage Engine Development" printed on their spines, and the blank spaces on the pages were densely filled with notes.

"Aren't these all mass-produced on assembly lines?" Li Ran gestured with his chin towards the three new engines. "Why do you still need to hand-machine them?"

"The ones on the assembly line are the standard versions." Lin Yu straightened up from the workbench, picking up a tablet. "These three are modified models, drawing inspiration from some design elements of the YF-100 and YF-115 designed by Chief Engineer Lü. The main improvements are in the combustion chamber pressure of the gas generator and modifications to the nozzle expansion ratio. Overall, the vacuum ratio should be increased by 3."

Up to 5 seconds.

He pointed to the turbopump housing of one of the engines, looking confident, and said, "We'll install it on the newly built second-stage rocket body later, and do a 300-second long-range hot-fire test in Launch Valley first thing tomorrow morning."

"So fast?" Li Ran asked instinctively, then frowned. "Wait, we have rocket commercial orders booked until next year. You're going to conduct destructive tests on the launch pad? Aren't you afraid of an explosion?"

Lin Yu scoffed at Li Ran, confidently stating, "Explode? Can't! That's talent."

He emphasized the word "talent" as if repeating a secret code that only he and Li Ran understood.

Li Ran understood.

Lin Yu's panel data flashed through his mind.

[Mechanical resonance: When debugging or diagnosing an engine, it can accurately pinpoint the root cause of the problem and has a chance to propose an improvement plan.]

This is a characteristic of system authentication.

Lin Yu's judgment about the engine was less the result of rational analysis and more an almost intuitive sixth sense.

Since he dared to say that, it seems he really can't blow it up.

Relieved, Li Ran stopped talking, found a good spot to stand, and prepared to observe the whole thing.

Over the next few hours, the pace in the workshop was astonishingly fast.

After undergoing cold-swing inspection in sequence, the three engines were transferred to the final assembly station.

A forklift delivered a second-stage rocket body from the United No. 1 assembly line, its silvery-white shaft gleaming with a cold, eerie light under the lamplight.

The engineers split into two groups: one group installed the engine, and the other group laid out the test sensor wiring.

Everyone's movements were precise and efficient, there wasn't a single wasted word, and even the sound of footsteps was barely audible.

It was six o'clock in the evening, and the sky was still bright.

Under Lin Yu's command, the three modified ZK-33F engines were seamlessly inserted into the tail section of the second-stage rocket.

Lin Yu walked around the arrow one last time, signed his name on the confirmation form, and then patted the railing hard.

"transport."

Soon, after a series of procedures, the second-stage rocket appeared on the transfer track as the sun set.

Bathed in the glow of the setting sun, the protruding sensors on the rocket's surface resembled shimmering Venus.

The following day, at 10:00 AM, the rocket launch valley.

The second-stage rocket used for testing was securely fixed to the giant deflector.

Unlike the complete Joint-1 rocket, a single second-stage rocket body does not have core stage support. The fixation method adopts a double-safety scheme of side clamps and bottom bolts.

All personnel within a five-kilometer radius have been evacuated, and the antennas of the telemetry and control stations on both sides of the valley have simultaneously turned towards the test stand.

In the testing hall, Lin Yu sat in the first row, with the screen in front of him divided into more than a dozen small windows.

Each window corresponds to real-time data from a key location on the engine: injection disc, turbopump bearing, gas generator, thrust vectoring nozzle —

"Thirty seconds left in the countdown."

"Ten seconds left in the countdown."

"Three, two, one, ignition!"

The pre-combustion chambers of the three modified ZK-33F units lit up almost simultaneously under the action of the auto-ignition agent.

A fraction of a second later, the main combustion chamber was ignited, and three transparent and blazing blue flames shot out from the nozzles, violently colliding with the high-speed jet of cooling water on the guide channel. The resulting water mist instantly engulfed the lower half of the entire test stand.

The roaring sound was weakened after passing through several layers of soundproof glass into the testing hall, but it still gave people the illusion of numbness in their feet.

But from beginning to end, not a single person was distracted.

Everyone's attention was focused on their respective assigned window.

Three hundred seconds.

From ignition to shutdown without a second's delay, it took a full three hundred seconds.

The moment the flame went out, enthusiastic applause erupted in the flight control center.

Lin Yu did not cheer along with the surrounding engineers. He lowered his head to record the last line of data on the tablet before taking off his headphones and slowly leaning back in his chair.

The various data displayed on the screen looked so good, it didn't seem like a first test drive.

The combustion chamber pressure stabilized at 18MPa, the thrust fluctuation was less than the threshold, the turbopump bearing temperature was within the safe range throughout, and the specific impulse value was even 1.7 seconds higher than the upper limit initially estimated by Lin Yu.

These data gave him strong confidence in two full-flow staged combustion cycle rocket engines still in the design phase: the "ZK-75" with a vacuum thrust of 75 tons and the "ZK-308" with a vacuum thrust of 308 tons.