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

The feeling of regret didn't linger on Lin Yu for long, because there were more important things waiting for him.

To ensure the successful test runs of the two prototypes, Lin Yu, having composed himself, took the prepared approval documents and immediately went to find Director Qi Kaifeng.

Accompanied by Director Qi Kaifeng, Lin Yu successfully completed the remaining procedures.

Soon, a group of employees carefully transported the two sealed, delicate, and valuable items via the internal rails to a valley 5 kilometers away.

Subsequently, under Lin Yu's direction, the staff inside the test stand disassembled the 'ZK-131'.

Upon inspection, the ZK-131 prototype was found to be intact, and the onlookers finally breathed a sigh of relief.

The next day, after a busy morning, the 'ZK-131' was finally installed on the test stand.

In the afternoon, after a short rest, Lin Yu began to check the checklist item by item.

After Lin Yu personally checked off all the projects, he solemnly signed his name.

Subsequently, the leaders of the test bench also re-checked according to the checklist, and signed their names after confirming that everything was correct.

Everything is ready.

The following morning, at 8:00 AM sharp, the final check before the test drive was successfully completed.

At 10:00 AM, the last batch of non-essential personnel were evacuated to the safe zone.

The commander-in-chief's voice rang out over the loudspeaker:

"Engine test countdown, one minute to go."

Thirty seconds.

"Ten, nine, eight, seven, ... three, two, one, ignite!"

As the ignition command is given, fuel is pumped sequentially into the two secondary combustion chambers through the high-pressure pipeline and ignition begins.

Subsequently, the fuel-rich and oxygen-rich fuels produced in the two secondary combustion chambers are pumped into the main combustion chamber for secondary ignition, and the nozzle begins to spray blue flames outward.

In the distance, a blue flame appeared in the previously calm field of vision, and as the throttle valve slowly opened, the flame began to expand.

The flames come into contact with the spray cooling system through the guide channel, instantly generating a large amount of white water mist that quickly envelops the entire test stand.

The specially designed test stand weakened the enormous impact layer by layer, and the test stand command hall, which was a little further away, was not affected at all.

Inside the command center, everyone, whether they understood it or not, stared intently at the data streams on the screens: thrust curves, combustion chamber pressure graphs, various temperature monitoring graphs...

Lin Yu not only had to keep a close eye on the rapidly refreshing data stream on the screen, but also listen to the roar of the engine, while simultaneously taking notes on paper.

The 50-second test run time passed quickly.

The shutdown command was issued, the fuel valve was shut off, and the blue flame contracted and went out within seconds.

The enormous roar echoed through the valley for a long time, accompanied by the hissing sound of the cooling water in the guide channel being instantly evaporated by the high temperature.

"It's a success?" one of the staff members asked in surprise. "I thought it would explode right on the test bench."

"That's really surprising. The 'YF-100' only passed acceptance testing last year, right?" Another employee was also deeply shocked. "These amateur scientists these days are really something else."

"It's probably thanks to Professor Lü. After all, he was the chief designer of the 'YF-100'."

Unfortunately, this conversation was not heard by United Industries and others.

After the engine successfully shut down and the first test drive was completed, Li Ran took the lead and rushed forward, together with Zhang Chengyuan, to carry Lin Yu on their shoulders.

Then, the three were tossed into the air by their colleagues who rushed over.

Meanwhile, Wang Bing, Su Qing, Gao Jingming, Shen Zijie, Song Xuewu, and others, who were far away in Gaolu Town, also received the news of the successful test drive immediately via text message.

Overjoyed, Wang Bing immediately notified the cafeteria to add a hearty dish for lunch.

Soon, everyone expressed their excitement through celebration.

After calming down, Lin Yu approached the chief commander of the test stand to discuss the test arrangements for the 'ZK-33' prototype.

To ensure maximum time utilization, it was agreed that Zhang Chengyuan would be responsible for arranging the test runs of the ZK-33 prototype.

Lin Yu and his employees disassembled and packed the 'ZK-131' into boxes, and transported it to a nearby testing facility in preparation for structural flaw detection.

Lin Yu looked at the figure that appeared in the factory with some surprise:

"Professor Lü?! What brings you here?"

"I just received news that the 'ZK-131' prototype has successfully completed its test run, and I was thinking of taking some time to come and see it." Professor Lü Chaoping looked at everyone, "I've been busy with the backlog of work at the factory these past two days and haven't been able to see it in person, which is truly a pity."

"You deserve credit for this as well. Without your guidance, we would have encountered countless pitfalls during the production process, and it wouldn't have gone so smoothly."

Lu Chaoping didn't reply, but looked at the machine behind them:

"This is for flaw detection, right? Hurry up and go, so we can proceed with the second, extremely long test drive after the inspection is complete."

Every minute here is precious; don't waste it.

Upon hearing this, Lin Yu stopped exchanging pleasantries, nodded to Professor Lü Chaoping, and then directed his colleagues to begin disassembling the parts and conducting flaw detection.

The next afternoon, the flaw detection work was completed. Looking at the report in his hand that read "No deformation or hidden damage to any parts, engine qualified", Lin Yu signed his name.

On the morning of the third day, ZK-33 successfully completed a 50-second test run, after which Zhang Chengyuan arranged for his employees to begin disassembly.

He had to make room for the upcoming long test run of the ZK-131, while also leading his team to conduct structural flaw detection on the ZK-33, which had just completed its first test run.

During the first test, the rocket engine performed perfectly, and Lin Yu boldly increased the ultra-long test time from the rated 1200 seconds to 1600 seconds.

If it weren't for the limited fuel storage, Lin Yu felt that 2000 seconds wouldn't be out of the question.

After a day of installation and inspection, 'ZK-131' returned to the test stand once again.

Everything went so smoothly. When the blue flames once again surged from the nozzle of the 'ZK-131', forming several Mach rings, Lin Yu felt a sense of déjà vu, as if the scene was familiar.

1600 seconds passed in the silent countdown of the crowd.

As the engine shutdown command sounded, Lin Yu cheered loudly to vent his emotions, and was then thrown into the air again by his colleagues who rushed up to him.

Lin Yu, who was in mid-air, glanced around and saw Li Ran smirking as she crouched down and retreated towards the door.

Two more days later, the ZK-33 prototype, having passed the flaw detection test, once again appeared on the test stand.

The 2000-second test drive time passed in the blink of an eye, and this time, everyone watching the test drive was unusually relaxed.

The familiar scene appeared once again. Although Li Ran had watched it four times, he still found it fascinating.

In a cheerful mood, Li Ran suddenly pointed to the faintly visible 'ZK-33' in the image and said:

"Don't you think this blue flame looks a lot like a gas stove?"