Chapter 2

As Hu Wenhai began to assemble the parts on the table one by one, Hu Shiwu realized that, as he had said, it was indeed just a toy.

From a technical standpoint, this was a genuine turbojet engine. It compressed air, ignited fuel, and then the expanded air was expelled through the turbine blades at the back—this principle applied to all advanced turbojet engines.

However, this high-sounding aviation engine, specifically developed for high-speed aircraft, seemed to have only one function in Hu Wenhai's hands: that of a toy. It was simply too "small," with a total length of no more than 25 cm and a weight of perhaps around 1 kg. After a quick glance, Hu Shiwu had these figures in mind.

How much thrust could this miniature turbojet engine produce? Two kilograms, or maybe three? It could only power a model aircraft.

Thinking about this, Hu Shiwu couldn't help but chuckle. His grandson was indeed a bit mischievous and playful, but his talent in mechanics was truly a credit to the Hu family! Other high school sophomores, no matter how skilled, could only make wooden model planes with rubber bands. But his eldest grandson, Hu Wenhai? Regardless of how rudimentary and miniature this turbojet engine was, most other kids wouldn't even have heard of it!

If a high school student could build an aviation engine, and if it really worked, wouldn't that make the news? Thinking this, the Hu family would truly have something to be proud of!

"Good grandson, how do you plan to do this? Grandpa will lend you a hand!" Hu Shiwu rolled up his sleeves and asked enthusiastically, staring at the parts in Hu Wenhai's hands.

"Perfect, I do need your help here." Hu Wenhai clapped his hands, stopped his assembly work, and pointed to the half-finished product in front of him. "The compressor turbine blades need to be dynamically balanced, and that's where your skilled hands come in!"

"Dynamic balance?" Hu Shiwu was taken aback, surprised. "My dear grandson, what kind of RPM are you aiming for that you need dynamic balance?"

Dynamic balance refers to the structural vibrations caused by the imbalance in the shape and weight of the turbine blades during rotation. These vibrations are not a big issue at low RPMs, but at high RPMs, they can cause instability in the blade operation.

According to Hu Shiwu's estimate, if the thrust-to-weight ratio was 2 to 3, the blade RPM would be below 10,000, making dynamic balance less significant.

Hu Wenhai scratched his head and replied, "The bearing material of this engine is not up to par, so I estimate that 80,000 RPM is the limit."

"80,000 RPM!" Hu Shiwu was startled after a quick mental calculation. That would mean a thrust-to-weight ratio of at least 5 to 6. Such a nearly 1 kg engine could provide about 6 kg of thrust.

If the thrust-to-weight ratio of the entire model aircraft was 0.5, the aircraft could weigh up to 12 kg—was this still a model aircraft?

"Hey—hey—" The iron door of the workshop was pulled open, and in the backlight, two people gently pushed a plane into the room.

Hu Shiwu weighed a delicate compressor wheel in his hand. The wheel was made of stainless steel, polished and heat-treated, giving it a very satisfying feel.

To perform dynamic balance, specialized testing equipment and formulas are typically required. Most factories cannot develop such products because the dynamic balance formulas are designed and developed by senior engineers, and the production process uses pre-calculated formulas and pre-calibrated equipment.

However, there are always workarounds. The highest achievement in machining precision in the 1980s was not CNC machines; it was still human skill.

Especially for someone like Hu Shiwu, a legendary figure, what other workers needed machines to determine, he could do with just his fingers and ears.

In essence, dynamic balance means making each blade of the wheel weigh the same so that the center of gravity is precisely at the center of the wheel. Hu Shiwu could determine which side was heavier or lighter just by weighing it in his hand. Then, using tools to remove a part of the blade's weight or correct the curvature, it was a simple task for his skilled hands.

Hu Shiwu began to handle the dynamic balance of the wheel, while Hu Hu and Lu Daming pushed a model aircraft over a meter long into the workshop.

It was a twin-engine, twin-tail, variable-sweep wing aircraft with a blended wing-body and side intakes, sleek and elegant like a swan's neck. As they say, a good aerodynamic design is always beautiful, and Hu Shiwu felt that this model aircraft had an indescribable beauty.

However, the paint job was a bit of a letdown. The green head and tail on a gray body gave it a rather outdated look.

"This plane looks familiar, it's not from our country, is it?"

"It's the American F-14 fighter, hehe, but with our country's air force paint job." Hu Wenhai laughed a bit sheepishly.

"This green head..." Hu Shiwu thought for a moment but didn't say the adjective that came to mind.

"Not outdated, but powerful!" Hu Wenhai laughed, running to the F-14 model and gently lifting the rear fuselage cover.

Hu Shiwu blew his beard, feeling helpless with his eldest grandson. Ever since Hu Wenhai could walk and talk, he would occasionally say things that were hard to understand. But to say he was just mischievous and playful wasn't quite right. As an old man in his fifties, Hu Shiwu saw a calm heart behind Hu Wenhai's playful behavior.

Hu Wenhai's "mischievousness" was not like that of other children, who were simply playing. To Hu Shiwu, there was a sense of enjoyment in his "mischievousness."

Yes, Hu Wenhai seemed to be enjoying and experiencing the feeling of play, rather than using play to explore the world. To him, there seemed to be no secrets in the world that he needed to discover.

This, perhaps, was the difference between a genius and an ordinary person. Hu Shiwu felt a deep sense of pride as he watched Hu Wenhai install the already assembled engine into the F-14 model.

The outer shell looked very light, probably made from aluminum sheets stolen from his father's 501 factory. In those days, state-owned enterprises had poor management, and it was common for even ordinary workers to take production scraps home.

The model had three landing gears that could retract into the fuselage. The fuselage was already equipped with various devices. Two sets of nickel-iron batteries were installed in the fuselage, connected to the aircraft's servomotors.

This made the model appear to have a very advanced fly-by-wire control system, but it was just an illusion. Three enhanced signal modules and antennas were placed in the F-14's nose to receive control signals for each control surface.

Hu Wenhai wanted the computer to automatically control the aircraft's attitude, but he couldn't find a programmable microcomputer chip in the entire city. In those days, even the old 8080 CPU was a rare item, and using vacuum tubes to achieve such complex control was beyond his capabilities.

What skills did Hu Wenhai have?

In the 1980s, when entertainment was scarce, it was almost impossible to be a shut-in. But no matter where or when, people always found ways to entertain themselves. The young people of the 1980s had their own hobbies and leisure activities. Without anime or American TV shows, they were more into geeky pursuits.

Radio, model aircraft modification, electronic circuits, and even kite competitions. If you were born in the 1970s and grew up in the 1980s, having a pair of skilled hands was a definite plus.

But Hu Wenhai was different from these amateur geeks. He was a geek from the future, returning from thirty years ahead.

Yes, Hu Wenhai was a reincarnated soul. One day, after turning forty, he woke up to find himself reborn in the 1970s. If he didn't take advantage of this wonderful age, wonderful era, and wonderful sky, wouldn't he be wasting it?

To make up for the life of a geek trapped in mundane affairs in his previous life, Hu Wenhai was determined to fully embrace the spirit of "tinkering" in this life.

In his previous life, as the son of an engineer, he became the chief process engineer at Ningbo Crystal, a battery factory disguised as a car company. His career choice had left the then eighty-year-old Hu Shiwu heartbroken for years.

But this didn't mean Hu Wenhai had no interest in mechanics. In fact, influenced by his family environment, he was also very talented in mechanical design.

In the early days, before websites like Guokr existed, he had already organized a group of enthusiasts to tinker with various DIY "big toys." He was one of the first players in China to build an F-14 model with a miniature turbojet engine, having designed and built one entirely by hand. He knew the F-14's specifications by heart, and this model was a high-fidelity replica.

However, after completing it, he barely had time to play with it. His work became increasingly demanding, and he solved a series of production issues, leading to a promotion and a raise. In his thirties, he married a beautiful bride who had just graduated from university, and the following year, she gave birth to a lovely daughter. As a father, he had even less time for such "unproductive" hobbies.

But in Hu Wenhai's heart, a geek's soul still burned.

Reborn, he had no grand ambitions, only one goal: to fully embrace the spirit of "tinkering" in this life!

City life, sleep well!