Black Corporation: Joseon [EN]: Chapter 405

405. A Short Story (2)

Sejong’s eyes lit up as he circled the tractor and road coach, examining the tractor from every angle.

“To bind the wheels with large bands of iron… truly peculiar, isn’t it?”

“It is called a continuous track, Your Majesty.”

“Continuous track?”

“If I may explain the principle…”

Hyang began to explain, but Sejong raised a hand to stop him.

“Enough. Set it in motion. I shall ponder it myself. It seems quite intriguing.”

“Yes, Your Majesty.”

‘I forgot! His Majesty is curiosity personified!’

At Sejong’s command, Hyang immediately stepped back and relayed the order to the tractor operator.

Fshh!

Upon receiving the command, the operator drove the tractor, and it slowly moved forward. After observing it move about 1 jang (approximately 3 meters or 10 feet), Sejong nodded.

“Indeed, in simple terms, it moves on a road made of iron. This would allow movement regardless of soft or muddy ground, to a certain extent, wouldn’t it?”

“Yes, that is correct.”

‘Unconventional as ever!’

“Hmm…”

Listening to Hyang’s response while examining the continuous track, Sejong posed a question.

“Is the steering of this tractor done with those two separate wheels in the front?”

“Yes, Your Majesty.”

Simultaneously with his answer, Hyang explained the steering mechanism installed on the tractor. As he explained to Sejong, Hyang added inwardly,

‘It’s essentially a half-track with a steam engine.’

Sejong, examining the steering mechanism (Note 1) that used an axle, gears, a lead screw, and a chain extending to the left of the vehicle body, turned to Hyang.

“I roughly understand how the steering works. Now that I see it, is the largest wheel at the rear of this continuous track the one that applies the power?”

“Yes, it is.”

“When I read the technical books created by the research institute and Area 51, I learned that the number of rotations of the inner and outer wheels differs each time a cart turns. Ordinary carts don’t matter because the wheels turn separately, but iron horses [early trains] have a problem because power is transmitted. To solve this, I heard that you have to differentiate the power transmitted to the two wheels or make the turning radius very large.”

“That is correct.”

Hyang nodded at Sejong’s point and continued,

“The iron horses currently operating in Hanseong [old name for Seoul] solve that problem by transmitting power to only one wheel. And the larger iron horses, which need to move faster with greater power, will follow the latter method.”

“So, does this tractor follow the method of the iron horses moving in Hanseong?”

At Sejong’s question, Hyang immediately answered,

“No, it is a new method.”

“A new method?”

Hyang took Sejong to the rear of the tractor and pointed to the underside of the vehicle.

“You can see it here.”

“Hmm?”

At the rear underside of the tractor, there was a large iron box, and the drive shaft and wheel axles were connected to that box.

“We have named it a differential power transmission device.”

The device that Hyang pointed out was a gearbox containing a differential gear.

* * *

The point that Sejong pointed out was the same problem that had been raised during the development of the tractor.

“A solution to this problem has already been found in the process of developing the iron horse, but wouldn’t it be possible to just transmit power to one wheel like that?”

When most of the developers submitted this opinion, Hyang shook his head.

“The iron horses in Hanseong run on well-maintained roads in Hanseong, follow dedicated railroads, and finally, the speed is slow, so there is no particular problem. But the problem is that the tractor has to go off-road.”

“Ah….”

The developers, nodding at Hyang’s explanation, realized what the problem was and wore expressions of despair.

‘Having to go off-road’ meant that power had to be transmitted to both wheels.

Looking at the despairing developers, Hyang muttered inwardly.

‘There was a famous advertising copy in the 20th century that said, ‘It goes on the road. It goes even if it is not a road.’

To solve this problem, the first thing the developers came up with was to install independent braking devices on both wheels.

“In simple terms, it’s the same method as the tanks used in World War I and World War II…”

Hyang shook his head as he looked at the developers’ proposal.

“It’s still too early… If we apply that as it is, there will be a transmission larger than the steam engine.”

Following Hyang’s instructions, the developers devised other plans, but no answer came easily.

In the end, as time passed, no answer came out, and the Ministry of National Defense’s nagging – there was a crime of taking away the budget under the pretext of development – only worsened, so Hyang intervened.

Hyang suggested a half-track steering system and a differential gear to the developers.

“Oh! There is such a method!”

“As expected of His Highness!”

Listening to the developers’ shouts praising him, Hyang muttered inwardly.

‘Thank you! General Motors.’

Hyang learned about this steering system and differential gear thanks to a black and white video produced by General Motors in the 1930s. (Note 2)

In the 21st century, Hyang – then Jin-ho – watched the videos by encountering an unknown algorithm on a famous video site and searching for and watching all related videos in an instant.

* * *

“Amazing. Such great technology and principles are embedded in this seemingly simple box…”

Sejong was sincerely impressed as he listened to Hyang’s explanation.

Jeong Cho, who had come along, also wore a proud face along with Hyang at Sejong’s admiring appearance.

“The essence of our Joseon’s physics (理學) [Neo-Confucian metaphysics] is embedded in it.”

Hyang, nodding at Sejong’s evaluation, added.

“It’s not just the principles that are included. Joseon’s best ironmaking and smelting technologies are embedded in the shafts and gears that transmit power. If I dare to say so, even if other countries learn about that principle, it will take at least 10 years to produce the same performance as that.”

‘In simple terms, this is the 15th century version of semiconductor technology.’

Sejong’s face became serious at Hyang’s words.

“I am proud, but we must also put our heart and soul into preventing the technology from leaking out.”

“Yes. Therefore, the steel mill must remain a state-owned enterprise.”

At Hyang’s claim, Sejong nodded with a serious face.

“That must be the case….”

* * *

With the tour of the tractor over, Sejong and his party boarded the prepared coaches.

Fshhhh! Fshhhh! Peep!

With the sound of steam escaping and the whistle blowing, the tractor slowly began to move.

Sejong, watching the cavalry moving alongside to escort them through the window, turned to Hyang.

“You said it was made for the artillery corps? Then, instead of pulling the cannons, wouldn’t it be okay to load all the cannons, shells, and gunpowder and move them all at once?”

‘That’s a self-propelled gun, isn’t it? But everyone thinks the same thing….’

Hyang, who thought of a self-propelled gun as soon as Sejong spoke, smiled wryly and replied.

“It is impossible.”

“Why?”

“It is because of the characteristics of the steam engine. The firebox (火口) [combustion chamber] must always be open.”

“Ah….”

At Hyang’s words, Sejong immediately nodded.

It would be terrible if the loaded gunpowder caught fire.

However, Sejong did not give up easily.

“Wouldn’t that problem be solved by creating a separate isolation space?”

“Gunpowder is dangerous not only with fire but also with heat. In particular, the most dangerous thing for fulminate of mercury, which goes into the detonator, is heat. Of course, we could create a sufficient isolation space, but then we would have to redesign everything from scratch. Starting with a more powerful engine….”

Hyang stopped talking and glanced at Kim Jeom. Sejong, who turned his head following Hyang, looked at Kim Jeom’s face, who was almost crying, and sighed.

“Hoo~. Yes, it would take a ridiculous amount of time and budget.”

“We can shorten the time a bit, but I can’t guarantee the budget.”

“I have no choice but to promise the future; it’s a pity.”

“Yes, the developers also came up with similar ideas, but they had no choice but to give up on that part.”

Hiding his disappointment about the ‘self-propelled gun,’ Sejong asked about other parts.

“Then, what is the towing capacity of the tractor? Surely, we don’t have to attach one to each cannon?”

At Sejong’s question, Kim Jeom glared at Jo Mal-saeng with a surprised look.

Seeing Kim Jeom’s face, which was even murderous, Jo Mal-saeng hurriedly reported on behalf of Hyang.

“To move at maximum, it can pull five Byeongshik cannons [Joseon-era cannons] and all the carts loaded with the shells and gunpowder that those cannons will use. However, for safety, it is designed to tow only Byeongshik cannons. Gunpowder and shells are transported using horse-drawn carts as before. However, even if only Byeongshik cannons are moved, we expect a significant increase in power.”

“Hmm… I see…. It’s a good plan.”

As Sejong nodded and affirmed, Kim Jeom and Jo Mal-saeng’s hopes and fears were mixed.

However, Sejong’s imagination did not stop.

“Crown Prince, even if we can’t load cannons and gunpowder because of the risk of explosion. Instead, how about loading soldiers?”

“Soldiers, Your Majesty?”

“Yes, if it has the power to tow five Byeongshik cannons and the shells and gunpowder to be used there, can’t we carry soldiers?”

“To do that, we need to redesign it….”

“No, instead of creating space in the tractor, we can armor this coach and connect it. What do you think?”

At Sejong’s words, one image came to Hyang’s mind.

‘Armored train? No… Something more similar is the BV206 [articulated all-terrain vehicle]? It’s similar… But the power has to be transmitted to the rear as well… Can we use a joint shaft for that part?’

After doing this and that calculation, Hyang replied to Sejong.

“I will think about it.”

“Okay, I look forward to good results.”

“But the budget….”

“Make it a long-term project.”

At Sejong’s firm answer, Hyang replied in a gloomy voice.

“…Yes.”

* * *

While such stories continued inside the coach, the tractor steadily moved towards Onsu-hyeon.

“The speed is good. Roughly speaking, it’s about the same speed as a horse’s trot. Is this the fastest speed?”

“The fastest speed is a little behind the speed of a horse sprinting, but running at that speed is prohibited because of cargo issues.”

Sejong, nodding at Hyang’s answer, looked around the inside of the coach he was riding in and asked Hyang.

“I see. By the way, it’s a very well-made coach. There is very little shaking.”

“Yes, we will improve this again and use it as a coach for stagecoaches and railroads. Both will have the same structure; only the size will be different.”

At Hyang’s answer, Sejong turned to Kim Jeom and said.

“We can save a lot of budget.”

“That is correct.”

“Kim Jeom will have less reason to take health tonics.”

Kim Jeom smiled wryly at Sejong’s joke and replied.

“All, it is thanks to His Majesty’s grace. Your grace is boundless.”

* * *

Thanks to riding the tractor, Sejong and his party were able to arrive in Onsu-hyeon in two days.

The officials and people who had gathered at the entrance of the district after hearing the news of Sejong’s visit waited for Sejong with anxious faces.

Chug-chug! Chug-chug!

“What is that sound?”

“I don’t know….”

The people and officials, tilting their heads at the sound they had never heard before, widened their eyes and opened their mouths when the tractor appeared at the entrance of the district with the cavalry.

“What is that?”

“The lump of iron is moving?”

Beeeeeep!

As a loud whistle sounded from the approaching tractor, the gathered people screamed and scattered.

“Oh my!”

“Save me!”

“It’s a monster!”

* * *

Note 1) It is good to refer to it.

Note 2) It is also good to refer to it.