Jin hurriedly checked Reiko's body. There was no damage anywhere. As expected of the world's most powerful automata made of rare materials.

"Reiko, help me fix the lab."

Jin stopped her from getting down on her knees and instructed Reiko to help him. Reiko obediently follows his instructions.

"Yes, sir. Father, I'll ask Soleil and Luna to help too.

"Right."

These days, Soleil and Luna, Reiko's assistant golems, often stay at Jin's house by the institute.

Fortunately, the two had come out when they were startled by the sound of Reiko breaking through the institute's wall, and Jin decided to have them help him repair the exterior wall.

It was fortunate that the broken wall was in an empty room.

The pieces were put back together and repaired using engineering magic <.

In less than half an hour, the laboratory was restored to its original state.

"Well, that's it. Thank you for your hard work, Soleil and Luna.

Yes, I'm back at home now.

Please call me again if you need anything else.

Soleil and Luna bowed and returned to Jin's house.

Jin checked with Reiko.

"Reiko, do you know the cause of this movement?

"Yes, father. Yes, father. It was because the output of the Magni Reactor was too large. Even that was less than one percent. ......"

"So it was less than one percent. ...... I knew it. ......"

Jin had an inkling. <

"When you use gravity magic to reduce your weight to near zero, you need about 20 percent of the output, but this new, force field generator, is it really that efficient?"

Jin nodded.

"Yes. Gravity magic, in other words, is magic that generates gravitational acceleration. But this force field generator is, as the name implies, generating force.

Gravitational acceleration, in theory, affects everything in a hypothetical straight line, whereas force acts only on a single point. No wonder the efficiency is different, Jin explained his reasoning.

Jin does not explain everything. Force is the product of mass and acceleration according to Newton's equation of motion <>.

I can imagine that the nature of this acceleration may be fundamentally different from that of gravity magic, but Jin, who is not a physicist, could only explain so much.

Nevertheless, it is enough to recognize the facts. Nevertheless, it is enough to recognize the facts and to apply them.

<, he adds, if we can make it less wasteful, we should be able to send a big stone, or even a rock, flying with less magic power.

I understand. I'll try it this time with even less magic power.

"Wait. It might be dangerous here, let's go to the beach.

So, Hitoshi and Reiko rode Pegasus 1 to the beach.

At Tatsumi Bay, Marin1 and Aqua1 were drying out the tengusa (a kind of seaweed).

"Master, what's going on?

Aqua 1 asks, to which Jin simply replies.

"Oh, I came to test Reiko's new function. It might be dangerous, so could you please stay away from me for a while?"

"Sure."

Jin himself puts up a solid physical barrier. Thinking back on it, I am still horrified to think that I would have been bounced out of the way when Reiko ran out of control just now.

However, it was only the magnitude of the force that Reiko could not control, not the direction, so that should not have happened.

"Okay, that's good."

Jin, who had deployed the Solid Barrier, signaled through the manacam. Reiko also replies through the built-in manacam.

"Yes, father. Then I will go.

With those words, Reiko starts to run forward toward the ...... sea at a speed of about 50 km/h. She does not move her legs. Well, maybe not really sprinting, since she is not moving her feet.

Leaving a line on the beach, Reiko flew in a straight line.

"Oh, wow!"

Reiko suddenly changed the direction of her sprint as she reached the ocean.

She instantly changes direction and comes back in a straight line. Then she came to a stop right in front of Jin.

"Father, I've found out the approximate degree of the speed..."

"I see."

Looking at her feet as she came to a halt, returning exactly where she had started, I could imagine that Reiko had grasped this new functionality.

"Then I'll try the three-dimensional maneuver your father mentioned."

"Take it easy."

Yes, sir. I'll go then.

Now Reiko's body started to move upward.

"Oh, oh!"

As Jin watched, Reiko slowly rose to an altitude of about 10 meters and stopped there.

"Father, please look."

With these words, Reiko jumped out horizontally this time. Her speed must have exceeded 100 kilometers per hour.

At first she flew in a straight line toward the sea, but when she reached the surface, she did somersaults. After ten somersaults in a row, he did a reverse somersault this time.

After one rotation, she did another somersault in the forward direction. In other words, Reiko is showing a figure-eight somersault.

Next, she ascends and descends rapidly. She flies horizontally in a large arc. With time, the speed became faster and the radius of the turn became smaller.

Jin watches excitedly.

Reiko then leaps upward at an angle with great force.

"Whoa!"

A boom. It's the sonic boom that happens when you cross the sound speed barrier. Naturally, Reiko is nowhere to be seen.

Then, in an instant, Reiko seems to come back, and is stopped on the sea.

Moving slowly, Reiko lands next to Jin.

"Father, is this enough for the test?"

Jin released the barrier and picked up Reiko.

"Yes, that's enough. That's great, Reiko!　You've done it!"

But she immediately lets go of his hand.

"Ah-chi-chi!"

Reiko had been flying around at supersonic speeds and was overheated by the adiabatic compression of the air.

"Are you all right, father?"

Reiko's temperature-generating function also has the function of cooling down her body that has been heated up. Thanks to this, Reiko, who normally would have been too hot to be burned, was only a little hot.

"Oh, I'm fine."

Still, Jin smiles happily.

"Reiko, is there anything wrong?　And you noticed anything?

"Yes, nothing is wrong. Yes, I have noticed that it is difficult to rotate my body.

"Oh, I see."

The current function is, as I say, only linear motion in the 3-dimensional axes ...... X-axis (horizontal 1), Y-axis (horizontal 2), and Z-axis (vertical) axes. If we add a rotational function to this, we can freely move and change the direction in three-dimensional space.

"All right, let's start improving it.

Jin and Reiko boarded Pegasus 1 and returned to the laboratory.

"Rotational force, or torque. Then, if the moment arm is short, the efficiency will be low. ......

Talking to himself, Jin added new functions.

To generate rotation, the point of action should be located far from the center of gravity.

Therefore, he equipped both shoulders and hips with force field generators for attitude control, which can be freely changed in any direction.

"That's it. Reiko, give it a try."

Reiko was activated again, checked again, and then tested a third time.

"Okay, let's go."

This time the test was to be conducted in front of the institute.

Reiko, who had ascended to 100 meters above the ground just to be sure, started with a slow rotation around her body axis and gradually increased the speed of her rotation.

If she were a human being, she would have been dizzy and fainted by now, but Reiko was unperturbed.

She then ascended and descended as if to check her condition. She also curled her body and rolled in the air.

"Oh, that's brilliant. ......"

Jin was on Pegasus 1, observing from 100 meters above the ground.

"Hmmm, we have to seriously consider the problem of air resistance when it comes to this. ......"

It is still inefficient for an object shaped like Reiko to go supersonic. Heat generation by adiabatic compression of air is also a problem.

"I wonder if we can do something about this by applying wind boundaries. ......"

Reiko waves to Jin as she flies freely through the air.

Jin begins to formulate a new idea as he watches her.