Black Corporation: Joseon - Chapter 387

Episode 387 That, Jang Yeong-sil. (4)

The next morning.

A new notice was posted on the bulletin board.

“Is it listed as a challenge record again? “Registration is frequent these days?”

“what? what?”

“Get that head off!”

Upon learning that a new notice had been posted on the bulletin board, researchers and craftsmen gathered around to read the notice.

The first thing researchers and craftsmen checked was the grade of the item. After the challenge record was established, it became a habit for everyone to check this grade first.

And the eyes of all those who checked the grades opened wide.

“huh?”

“What grade…”

The newly posted notice had two grades applied at the same time.

Grade: Gogo Ha Wukong Yi San Sang.

There were two extreme levels attached at the same time.

The unexpected grade assignment made people look at the content in more detail.

-Notice of new registration in Dojeonrok.

Date: March 17, 1433.

Initiator: Jang Yeong-sil

Content: Create a ship propulsion device by applying the shape of a pinwheel.

Grade: Go Go Ha Wukong Yi San Sang

“Ah!”

“this!”

“You idiot for not thinking about this!”

Joe’s researchers and craftsmen, who were tasked with developing the propulsion device, slapped their foreheads and blamed themselves after reading the contents.

* * *

Pinwheels were not unfamiliar to Koreans. It was one of the toys that every boy played with.

Depending on the region, pinwheels, called ‘pallanggaebi’, ‘dorami’, or ‘hoehoea (回回兒)’, have been a toy that has been around since before the Joseon Dynasty. At first, it had a strong shamanistic nature for wishing for a good harvest – a representative example is the ‘150 Crest Gari’, which is attached with ears of five grains on the first full moon of the first lunar month – but later it became a toy for children. (Note 1)

Even though there are items that accompanied our childhood like this, they are placed in strange places. He slapped himself on the forehead because he was blaming himself for looking for an answer.

After a period of self-reproach, researchers and craftsmen all had the same question.

“But why did we get polar opposite ratings at the same time?”

The researchers, who couldn’t think of a suitable answer after thinking about it, talked with their colleagues.

“Do you know why it was rated that way?”

“I don’t know. Do you happen to know what it is?”

“Shall I ask you a question?”

When one researcher mentioned scent, other researchers responded simultaneously.

“Can you answer me?”

* * *

For the researchers and craftsmen at the research institute, incense was a ‘nice but difficult boss.’

If a task was failed or the due date was missed, the head carefully looked into the reasons. If the incident was not caused by the negligence or carelessness of the people in charge and no casualties were incurred, the local government rarely punished the incident.

Instead, what Hyang wanted from those in charge was a clear teacher.

If you look at it this way, Hyang was a good boss, but in other ways, he was a difficult boss.

There were only two areas where the scent was annoying.

One was the budget, and the other was asking about the assigned mission without even thinking about it.

‘Finding out why this rating was given is the first step to success.’

Because Hyang said this, the researchers had to think hard about the question, ‘Why this grade?’

“He always wants us to do our best.”

“Isn’t that how much you trust us?”

Although they had to go through a lot of hardships from the start, the researchers did their best, believing that it was all for their own good.

But this was half the truth.

“If progress is to continue from generation to generation, it must be digested and moved on.”

If researchers and craftsmen did this out of the belief that they had to properly digest what they had learned to properly pass it on to the next generation, the other part was due to the selfishness and limitations of incense.

“Why are you trying to just spoon it on? Even in group assignments, you get criticized for doing that. Are you a spoon with deep roots? And…”

Hyang looked at the reports with a perplexed expression.

“First of all, I was a fan of making and watching, but it’s not wise to use my brain like this… If I had been good at this, would I have gone to the science department in the first place or the liberal arts department? “Why was I told I looked like a 19th century inventor?”

The evaluation of the doctor who consulted about 21st century scents was as follows.

‘He’s an inventor like Leonardo da Vinci, but not a theorist like Kepler and Einstein.’

Hyang, who had reached his limit due to the limitation of ‘I’m not good at high school math,’ gave up on explaining under the pretext of ‘You have to find the answer on your own to make it your own.’

* * *

In any case, since there would be no answer even if asked to Hyang, the researchers immediately began research.

And as soon as I started studying, I was able to understand why I received two grades at the same time.

It was very easy to catch the shape because there was already information that said, ‘It should be modeled after the shape of a pinwheel.’

The researchers made quick progress by making pinwheels using paper and bamboo stalks.

“After all, four wings catch the wind better than two wings. “Then wouldn’t it be better to have four moon wings on the propeller?”

“That would be great.”

“ah! Have you ever competed with a pinwheel?”

“Yes.”

“Then wouldn’t it be better to make the shape of the wings similar to pinwheels for high-flying competitions?”

“Oh oh! “That’s great!”

Other researchers welcomed and agreed to one researcher’s suggestion.

There were two ways to play sparring with a pinwheel.

One was to run to a designated place or stand there and face the wind and compete to see whose pinwheel could turn easily.

The other was to carve bamboo into the shape of wings, connect them to a mandrel, and then rub them together with both hands to compete to see who could fly higher.

(Note 1)

Progress progressed quickly because there was a memory of a toy called a pinwheel that one had familiarly played with in childhood, regardless of whether it was a child of a noble family or a child of a commoner or a commoner.

“If I do this, the results will come out quickly, right?”

“That’s right. Truly a struggling junior.”

The researchers were optimistic about the results, but it wasn’t long before they realized why it received the ‘Wugong Yisan Award’.

* * *

The first thing that stopped them was the ‘optimal wing tilt.’

“To put it simply, a wing tilted like this would push water… Then the angle…”

While researching to find the optimal angle, another variable arose.

‘Even if the angle is the same, if the shape and size of the wing changes, the efficiency changes.’

“Holy shit! “Let’s give it a try!”

The researchers and craftsmen swore, rolled up their sleeves, and stuck to design and experimentation as variables slowly appeared and grabbed hold of their ankles.

Researchers and craftsmen created dozens of types of screw propellers by carving wooden boards around.

A method of making and combining the shaft joint and the wing separately, a method of shearing the joint and the wing as a whole, changing the number of wings such as narrow and wide wings, 4 blades, 6 blades, 8 blades, etc…. Before we knew it,

the development department was in charge of the development department . The workshop and warehouse were filled with wooden screw propellers that were difficult to count.

Amidst all the trial and error, another variable caught up with them.

It was a vibration.

In one corner of the development department’s lab, there was a wind-up engine made by Jang Yeong-sil. Researchers investigated performance by attaching a screw propeller to a shaft connected to a wind-up engine.

Wow!

As the screw propeller connected to the wind-up engine began to rotate at high speed, the power shaft began to slightly vibrate up and down.

“huh? Why is the axis shaking? Hey guys!”

A keen-eyed researcher discovered something unusual and called his colleagues together.

Colleagues also checked for vibrations, but here the researchers made a fatal mistake.

“Isn’t it the vibration caused by the mainspring turning? “A similar thing happened in the old water train.”

“is it?”

“Let’s put it on a boat and test it out.”

In this way, a model ship equipped with the most efficient 8-blade screw propeller was floated in the water tank.

“start!”

When the experiment using the model ship began, the researchers’ complexion turned white.

“Why is my stomach like that?”

The ship started rocking back and forth, not moving straight, but leaning to one side and moving diagonally.

“stop! stop!”

The researchers quickly stopped the experiment and searched the ship thoroughly to find the cause, but they could not easily find it.

“I can’t help it. “Let’s stop here first and write a report and upload it.”

* * *

After receiving the report, Hyang suppressed the itching in his mouth.

‘The reason the ship was tilted was obviously due to the torque, and the vibration problem… Couldn’t it be because the wings were set in even numbers? As far as I know, the screws on a ship always come in odd numbers, right?

In fact, large ships used two screw propellers to prevent the ship from moving straight due to the heeling torque/moment acting between the ship and the propeller. (Note 2)

And the screw wings of ships. is made of odd numbers. The reason is that in the case of an even number, the number of resonant frequencies occurs as many as the divisors, but in the case of an odd number, only one resonant frequency occurs, creating various types of problems, including vibration.

‘That’s why even in the 21st century, all kinds of cutting-edge technology was mobilized to make that simple-looking screw propeller, and it ended up putting Japan at risk, right?’

During the Cold War, Japan’s Toshiba exported large, ultra-precision machine tools to the Soviet Union in violation of a contract with COCOM (COCOM Export Control Committee against Communism). Thanks to this, NATO countries, including the United States, began to have difficulty tracking Soviet submarines.

After discovering that the culprit was Toshiba, the United States immediately imposed an export ban on Toshiba, and from this point on, the decline of Japan’s electronic products and semiconductors began.

It was a long time before Hyang was even born, but the reason Hyang remembers this is because when Japan excluded Korea from the whitelist and imposed trade sanctions, he mentioned this incident on the Internet, saying, ‘The Japanese cause more accidents!’

Because of this, I had to force my itching mouth to suppress the scent.

‘This is something you have to instill in your body through trial and error! ‘Only then will I be able to use it better in the future!’

Torque and resonance issues were important to be aware of as they apply to many fields.

* * *

While pondering over a difficult problem that was not easily resolved, another variable dragged the developers’ feet.

This time it was a question of the material used to make screw propellers.

Through repeated experiments, screw propellers made of wood broke down faster than expected.

“No tree! “Let’s try some other things!”

In this way, a screw propeller was made from iron and copper.

Due to problems with manufacturing technology, the size of the prototype was quite large, so Jang Yeong-sil had to make a model ship 1/10 the size of the actual ship.

The model ship, which was made large and equipped with a small steam engine, was tested in Hansoo and also failed.

In addition to the vibration and tilt, the blades of the screw propeller were also deformed.

In the end, researchers were able to figure out why this incident was a ‘Wugong Yisan Sang’.

* * *

While the researchers were having a hard time, Jang Yeong-sil found the scent again.

“Sir, I have something in mind.”

“Give it to me now!”

* * *

Note 1) Korea Creative Content Agency. Cultural prototype library. Pinwheel.

http://www.culturecontent.com/content/contentView.do?search_div=CP_THE&search_div_id=CP_THE013&cp_code=cp0205&index_id=cp02050075&content_id=cp020500750001

Note 2) https://m.blog.naver.com/bjgim21/130161709562