The first thing Jin asked was the most basic of basics.

"You know the principle of a rocket engine, don't you?"

"Yes, I do."

Jin then decided to explain about the rocket engine he had found.

"The rocket engines that have been considered so far have obtained thrust by utilizing the expansion of air caused by . But the rocket engine we found uses <>."

"......"

"The rocket engine uses intermittent small explosions to generate propulsion. I estimate that it can provide three to five times more thrust than the previously studied ."

"Oh!"

"That's amazing!"

We must put this to practical use!

<

"Mister Jin, please tell us what's next."

"Yes. ...... This explosion will be done by magic, so it doesn't need fuel or oxygen supply. We only need to supply <> or <>, so fuel tanks are no longer necessary and the overall structure can be simplified."

"That's true."

"The problem is the supply and control of the mana. ...... and the fact that it's an explosion means that it has a lot of propulsive force, so it won't be good at low speeds."

"The heat resistance of the engine is also important since it uses fire magic.

Arnold added to Jin's explanation.

"That is true. But this will contribute to increasing the speed of the aircraft!"

"I'm sure it will."

Jin is also hopeful that this could be an alternative propulsion system to the <>.

However, as noted earlier, he speculated that it might not be good at low speeds.

(Well, in that case, I suppose we could find a way to release the pressure of the explosion.)

There were several possible ways to do this.

The combustion chamber of a rocket engine ...... explosion chamber?　Make an appropriate hole in ...... to release the pressure in other directions than the direction of the jet.

Wrap the explosion with a boundary to reduce the force.

Variable jet aperture (narrowing the aperture increases the jet velocity and widening the aperture decreases the jet velocity).

The following is an example.

It is a promising technology.

"It seems to be difficult to control. ......"

<

"I think we need to repeat the experiment on the ground to get the control data, and then ...... again with the experimental aircraft.

Jin advises.

"I think it would be better to use an airship for the experimental plane. How much propulsion can be obtained by how many explosions, and repeat the process.

The control data is stored in magi crystals and can be applied.

Of course, control will be left to a special control core.

"Well, is it impossible for the pilot to control it directly?

"I don't think so in the beginning."

< because of its linear output characteristics, but Jin thinks it is unlikely to work so well with the .

It was thought that if enough control data could be gathered, a conversion table could be constructed to produce output in response to throttle, which would make maneuvering much easier.

"I understand. Let's take Jin-sama's advice and collect the data carefully.

"I hope so."

"In that case, it would be better to conduct joint research with the on the control core of the control data.

Thus, the Aerospace Laboratory decided to develop the Magi rocket engine (tentative name) in collaboration with the .

* * * * * * * *

As it was getting late in the evening, they decided to stay the night at <>'s accommodation facility.

While Jin is relaxing with Reiko, Arnold has to write a to the Kingdom of Selroa.

Somewhat surprisingly, Arnold is not very good at writing reports.

When Jin went to Arnold's room to go to the dining hall for dinner, he was struggling with the report paper in front of him.

"Arnold, you look like you're having a hard time ......."

"Oh, Jin. I'm not very good at this kind of thing. ......

"Anyway, why don't we go to the cafeteria?"

"Yeah, sure. ......"

Arnold stood up, leaving his report unfinished.

I've always had a hard time with reports," he said.

"Well, I guess I understand a little. ......Chel, Arnold, don't you take your reports very seriously?

Yes, you're right.

I knew it.

Jin knew that too.

While research reports need to be written in a well-structured manner so that nothing is left out, reports are a little different.

At the company where Jin worked in modern Japan, he was required to submit a report when he visited a technical exhibition such as <>, but the boss who received the report would discard it without even looking at it.

Knowing this, Jin unwillingly learned to cut corners properly. .......

Aside from that, Jin has one piece of advice for Arnold: "Get Chelle to help you.

"Get Chelle to help you.

"Get Chelle to help you.

"Chelle?"

"Yes. Chelle's got a great mind. Her memory, her organization, it's more than human. I'm sure Arnold knows that better than I do.

"That's what I thought. But this is my job. ......

"Even Chelle was created by Arnold. The work that Chel did is as good as if Arnold had done it. Right, Chell?

"Yes!"

Chelle, who had come with me and was standing behind Arnold, answered Jin's question with a burst of energy.

"Oh, I see. Well, I'll leave it to you.

"Yes, leave it to me!

Chelle replied with more energy than ever.

She replied with great vigor.

What Jin said was right on the money.

After dinner, Arnold asked Chelle to summarize the report and stared at it with half surprise and half delight as it was quickly completed.

"Mr. Arnold, I have finished.

Fifteen minutes after he started writing the report, it was completed on 10 sheets of A4 paper.

"That was fast.

The content of the report is absolutely perfect.

Arnold was relieved to know that he would be able to submit the report tomorrow.