Chapter Thirty-Five: Assigning Projects

Finally, before darkness fell and the workday ended, all the data was roughly determined. Looking at the several pages filled with dimensions of the connections between each part, it truly felt that the day’s efforts had not been wasted.

This was the research atmosphere he yearned for. Although, compared to the institute’s “large-thrust aircraft engines,” the current project seemed less prestigious, its importance to the institute was by no means inferior. Now, the major components had to be divided among the six members of the project team. Naturally, Yang Hui could not be excluded; he was a crucial force in research and development. Most importantly, in a research institute, no matter how high one’s official rank, real respect ultimately depended on genuine skill. At this moment, Yang Hui could not afford to lag behind.

“Everyone, take a look and choose which subproject you’d like to take: there’s the combustion chamber and fuel supply system, casing and diffuser cone, bearings and bushings, compressor wheel and diffuser, turbine and guide vane, and the engine starting system.”

Six subprojects for six people—just enough to go around. At first glance, the workload seemed evenly divided, but in practice, some parts would inevitably be more challenging. It remained to be seen who would encounter difficulties, and if someone fell behind, those ahead would have to lend a hand.

Seeing no one eager to choose first, Yang Hui thought for a moment. He realized that, as project leader, he should set the example and not pick the easiest task.

“Alright, I’ll take the lead. I’ll handle the combustion chamber and fuel supply system. The rest of you can choose according to your preferences; if you’re slow, you’ll end up with whatever’s left.”

He selected a critical subproject—the difficulty of the combustion chamber would depend on his own choices. If he opted for a safe ring-tube design, there shouldn’t be much trouble. But if he chose an annular combustion chamber, the challenge would be greater.

With someone taking the lead, the rest followed suit. Liu Wang chose the casing and diffuser cone, Pan Wen took the turbine and guide vane, Zhong Jianxue picked the more difficult centrifugal compressor wheel and diffuser, Xie Lianfa, who had already calculated most of the bearings, naturally selected bearings and bushings, and finally, Long Derong ended up with the starting system.

Each project seemed relatively simple—take the starting system, for example, so straightforward that no one wanted it, leaving it to Long Derong. Yet, in the end, the starting system turned out to be the most challenging.

After copying down the necessary specifications for their respective projects, everyone buried their heads in work, striving to finalize their designs as soon as possible.

Seeing that it was still early, Yang Hui began his own project. He was more than capable of finishing it himself. After all, he’d spent years at the test flight institute and had seen all kinds of engines. The various combustion chamber designs he’d encountered during test flights always required consulting with the designers about their design philosophies. With this knowledge, Yang Hui could easily create his own design: an annular combustion chamber.

In the early days, during the 1940s and 50s, most centrifugal turbojets used segmented combustion chambers, making the engines look rather unsightly. But those were limitations of the era. Now, with the adoption of annular combustion chambers, centrifugal turbojets would no longer appear so unattractive—the smooth ring-tube combustion chamber would draw many admiring eyes.

Deciding on a ring-tube combustion chamber, and given that centrifugal engines had only a single stage centrifugal impeller, the engine would be short and stout, but this left ample space for the combustion chamber. Thus, it could be made longer, reducing technical difficulty. In later developments, annular combustion chambers became progressively shorter, leading to the so-called short ring-tube combustion chamber, but for now, there was no need to worry.

With fewer restrictions on length, the rest was straightforward. To ensure efficient operation, he chose to distribute six fuel nozzles evenly within the flame tube, which would be installed directly inside the combustion chamber.

But just as he was proceeding, Yang Hui encountered an unexpected major issue. In conventional engines, fuel sprayed into the flame tube must be atomized, and the usual blade-type swirl atomizer was structurally complex—clearly unsuitable for model-level turbojets.

The challenge was clear: fuel must be atomized for effective combustion, but model engines couldn’t use overly complex atomizers. A new, simple, and effective atomizer had to be designed to meet combustion standards.

This was no small matter. “Simple and effective”—easy to say, hard to achieve. If such a design were possible, it would have been installed in aircraft engines long ago; the continued use of swirl atomizers showed there were reasons for it.

In fact, there are two main methods for refining fuel in aircraft engines: blade swirl atomizer nozzles and fuel evaporation. Swirl atomization is anything but simple—quite complex to manufacture. Even in model-level turbojets, it's troublesome. Most crucially, with only two months to finalize the design, there was no way to implement the swirl atomization method.

So, unconventional shortcuts came into play—what some might call cutting corners. In the DIY model aircraft community, for the sake of simplicity, some devised preheating and ignition on the ground, eliminating the atomizer altogether, using a simple evaporation tube instead.

Yang Hui certainly intended to take this approach, for several reasons: first, as mentioned, to keep up with the tight schedule; second, to minimize parts and simplify the engine; third, not a technical issue but a commercial one. Who’s ever seen a new product debut with the most advanced design right out of the gate? Every shrewd manufacturer squeezes every drop of profit from each generation before releasing “new technology” that’s been gathering dust in the archives. As a developer of model turbojets, it was only right to take a gradual approach and earn steadily.

At this thought, Yang Hui gave a sly smile—these were all lessons learned from foreign businessmen. After the opening up, foreign firms brought products a generation behind international standards, all to make more money. If you lacked the technology, too bad. Now, Yang Hui was capitalizing on the fact that no foreign company had adopted this method yet, planning to cash in first, and release new technology once foreign firms caught up. What could be more satisfying?

Looking again at his sketch, it was much simpler without fuel atomization: just a combustion chamber with a flame tube, a basic fuel supply line, an evaporation tube, and an igniter.

Once the preliminary design was finished, he would consult with Wu Dabo and Section Chief Wu to finalize it.

But first, some necessary calculations had to be made, especially for certain curved surfaces of the combustion chamber, which had strict requirements. A curve too steep could seriously affect combustion stability, or even cause uneven heating and burn out the chamber.

He employed every method and formula at his disposal, including theoretical formulas developed in later generations—calculating matrices, functions, limits, all at once. To most people, it would be daunting, but for professionals, these were just tools.

Unconsciously, time had passed well beyond working hours. The sky was already dark. Yang Hui looked up to see everyone still immersed in their work, unconcerned about the time. Some sat in various postures, and a few sheets of draft paper lay scattered on the floor. Smiling, he stood up and walked toward the door to turn on the lights.

Calling everyone to leave at this point was unwelcome—it could disrupt their train of thought. Yang Hui would never do such a thing.

Just as he reached the switch, the lights came on ahead of him. Surprised, he looked up to see Secretary Liu from the institute. Secretary Liu, now in his fifties, was curious about the only department still open. Arriving, he saw Yang Hui about to turn on the lights and kindly did it for him.

Seeing the secretary, Yang Hui greeted him. Though the secretary had a bit of a scheming reputation, and his authority was diminished in a research institute, he remained one of its leaders and deserved basic respect.

“Secretary, why—”

Yang Hui hadn’t finished speaking when the secretary gestured for silence, pointed to the room full of diligent workers, smiled and nodded, then signaled Yang Hui to continue his work, turned, and left.

As he walked away, Secretary Liu was deeply moved. The scene reminded him of the institute’s full-throttle days, when everyone worked overtime just like this. Now, he couldn’t help but feel nostalgic. Though he was only a political officer, he had witnessed the institute’s journey over many years, and it was impossible not to feel sentimental. He said nothing, but his support for the model aircraft project grew—it carried the hope of the institute’s revival.