Imperial Japanese Space Force - I traveled back in time to 1901

Chapter 28: Engine Development



Let's go back a little to April 1919.

"Lieutenant Miyake, these are the design blueprints for a small, versatile engine. The materials for the piston rings and bearings are also specified in detail. Please work with Lieutenant Yonekura to achieve mass production of these engines as soon as possible."

Lieutenant Miyake was tasked with establishing the Technical Officer Course at the Space Force Military Academy while simultaneously overseeing the mass production of small, versatile engines.

At the time, Japan's engine development was in its infancy. In March 1919, Osaka's Engine Manufacturing Company had produced a prototype truck at the Army's request, but it had not been adopted. Domestic engines for automobiles were still a distant dream.

Takashiro Soryu provided three types of engine designs, all based on 21st-century ISO standards:

1. Air-cooled, single-cylinder, 4-stroke OHV small gasoline engine

 a. 200cc to 350cc, nearly identical design.

 b. Used for general-purpose pumps and agricultural machinery.

2. Air-cooled, single-cylinder, 4-stroke OHC small gasoline engine

 a. 50cc to 125cc, nearly identical design, integrated with a 3-speed transmission.

 b. Used for small motorcycles.

3. Air-cooled, single-cylinder, 2-stroke engine

 a. 25cc to 40cc, nearly identical design.

 b.Used for lawn mowers and outboard motors.

Soryu prioritized improving engine technology. A more powerful engine would enable the development of high-performance vehicles and aircraft.

For example, the engine of the Japanese Army's Type 97 Medium Tank, developed in 1937, had a displacement of 21.7 liters and produced about 150 horsepower. In contrast, the engine of the Self-Defense Forces' Type 90 Tank, developed in 1990, had a similar displacement of 21.5 liters but produced 1,500 horsepower—ten times the power.

A powerful engine would allow for thicker armor, increasing survivability, and enable the mounting of high-powered weapons. The benefits were immense.

However, in 1919, Japan's industrial technology was still in its early stages. There were no companies capable of outsourcing parts manufacturing.

Thus, Miyake decided to produce all prototypes within the Space Force.

Fortunately, 60 students from industrial high schools across the country were recruited for the Technical Officer Course. They were skilled in using milling machines, lathes, welding, and casting. Miyake divided them into teams, assigning each team to produce specific components.

At the same time, students from rural areas enrolled in the General Course were trained in using machine tools. Although called the Space Force Military Academy General Course, it functioned more like a vocational school. To achieve mass production, the manufacturing process had to be simplified to the point where even female students could produce parts after a short training period.

Until the Space Force's arsenal was equipped with machine tools, prototypes were produced using machinery borrowed from Tokyo Technical School. By summer, all necessary machine tools were installed in the arsenal, improving efficiency.

Miyake emphasized information exchange between teams. At the time, Japanese craftsmen guarded their techniques closely, believing that knowledge should be passed down through apprenticeship. Miyake abolished this outdated practice, holding weekly meetings where teams shared improvements and ideas. The best-performing team every two months received an "Excellence Award" from the Regent.

The students worked tirelessly, dreaming of receiving an award from the Regent. For commoners in that era, being personally honored by the Regent was beyond imagination. Returning to their villages with such an award would be cause for celebration.

"If I get an award from the Regent, I'll go back to my village and marry Chiyo!"

With such dreams driving them, the students threw themselves into development.

For parts requiring special alloys, such as piston rings and bearings, Miyake collaborated with Lieutenant Yonekura. Soryu knew the necessary elements but lacked detailed knowledge of composition ratios and firing temperatures. Through trial and error, they achieved the required strength and durability.

They also improved the durability of rubber used for oil seals.

The ignition system used the simplest magneto ignition, which could be easily manufactured at the time.

By December 1919, the first prototype was completed: a 200cc air-cooled, single-cylinder, 4-stroke OHV small gasoline engine.

With the choke closed, the starter rope was pulled forcefully.

"Vroom! Vroooom..."

"We did it! It's running! Success!!"

"When this engine goes into mass production..."

Everyone hugged and celebrated. The engine's performance was top-tier for the time.

With a displacement of 200cc, it produced 5.6 horsepower at 3,300 rpm and passed a 100-hour continuous operation test.

For comparison, the 1920 Harley-Davidson Sport had a 584cc engine producing 8 horsepower.

The design, based on 21st-century engine pumps, prioritized mass production. It was also designed to tolerate the low-quality oil and gasoline of the time.

Preparations for mass production began immediately. The manufacturing process was divided into specialized steps to efficiently produce components. Students from the General Course were trained and assigned to the production line, with male technical officers serving as instructors. Many female students from rural areas quickly formed relationships with the male officers, leading to numerous marriages. Marrying a technical officer became a goal for many female students.

"Well, it's good that they're happy, but I won't allow early retirement for marriage. We'll set up childcare facilities, so even if they have children, they'll keep working. The Space Force is equally demanding for men and women."

Initially, production was limited to the Space Force, but the technology was eventually transferred to external factories to boost Japan's industrial capabilities.

By June 1920, production reached 1,000 units per month. By June 1921, it had increased to 30,000 units per month, with engines exported to the United States and Europe.

These engines also played a role in alleviating unemployment during the post-war economic panic.

"Is it safe to export such high-performance engines? Won't foreign countries develop nuclear weapons faster with advanced technology?"

"It's probably fine. I understand your concern, Liliel, but the basic technology of internal combustion engines hasn't advanced much since the 1920s. Control systems and materials have improved, but the basic structure remains the same. Besides, Harley-Davidson in the U.S. already produces engines with similar performance. Ours are just cheaper and more reliable."

Agricultural machinery using these engines was also developed. The development of small motorcycle engines and 2-stroke engines progressed smoothly.

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A/N: Thank you for reading Chapter 28!

The engine development marks a turning point for Japan's industrial and military capabilities. What will this mean for the future?

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