Goshujin-sama to Yuku Isekai Survival! – Chapter 252

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Chapter 252 – Mobility Device and Air Bikes



The sky and the ground are overturned many times, and intense pain runs through my entire body. A tingling sensation in the back of my nose and a dizzying sensation also come over me at the same time. I feel like I’m going to cry.

“Are you okay?”

“Do I look okay?”

“I can’t see clearly.”

I replied to Isla’s voice that was coming down from above my head as I lay prone on the ground, and she stroked my head. It’s good that you stroke my head, but things hurt all over my body, Isla-sensei.

“No bones are broken for now.”

“That alone is a great step forward…”

I put my hands on the ground and lift up my upper body, my body shaking in pain.


Isla brought the mouth of a bottle filled with red liquid close to my mouth, so I accepted it and took a sip of the liquid inside. The taste is sour and not that good. But as soon as I swallowed it, the pain in my body disappeared. Life Potion-san is as good as I expected.

“Hah… What a troublesome thing.”

I stood up and tapped the abominable object perched on my waist with my fist.

Equipped on my waist is a prototype of a high-mobility device that I began developing after talking with Sir Leonard and Danan the other day. The concept is to create explosive acceleration with a pair of small propulsion devices attached to a metal frame, but it is difficult to control. Not just difficult, but maybe impossible.

In the past two weeks, I have broken my bones thirteen times, fainted eight times, and lost count of the other injuries I have sustained. If it had not been me doing the testing, there would have been five or six deaths.

“Kosuke, I still think it would be better to have the test done by a physically gifted beastman or something instead of you.”


I groaned at Isla’s worried gaze as she stared up at me. To begin with, I think that the human body is not designed to run, jump, and bounce on the ground at speeds of 30 or 50 kilometers per hour. I think so because I’m in a lot of pain.

“Humans are no match for beastmen and other physically strong types of subhumans in terms of reaction speed, skeletal structure, or physical toughness. In extremely rare cases, there are humans in that category, but it’s not with Kosuke.”


It is frustrating, but Isla has a point. In the beginning, when the output adjustment was unstable, the impact of acceleration alone was enough to make all the bones in my body creak, and I almost suffered a back injury. The current prototype has a propulsion system attached to the frame… rather than a frame; it is more like waist armor with a solid structure from the thighs to the back. The reason is that the initial frame with a propulsion system would have put a tremendous burden on the spine and hip bones.

“I don’t think the idea is bad…”

“It’s interesting. Innovative.”

“But the progress is clearly better over there.”

“Because the basic technology is well established.”

From where Isla and I were looking, we saw an air bike moving at a comfortable speed. Mechanically, it was the same as an air board. However, the number of propulsion units is three in total: one medium-sized unit for the main engine and two smaller units for changing direction, and the smaller propulsion unit for changing direction is driven by moving the handlebars to the left or right.

One small floating device is used at the front and rear of the chassis, which is now running smoothly. We are still trying to determine the best arrangement, size, and power output of the levitation devices, including one in the center and a larger one.

“If it is put into practical use, it will be more convenient than a horse.”

“As long as magic crystals are available, the burden on logistics will be far less.”

The benefit the military will gain from mechanized means of transportation and delivery is, of course, a reduction in the logistics burden.

Generally speaking, the weight of food consumed by a human soldier per day is between 1 kg and 2 kg. You can assume that this is a minimum figure, not including the weight of the water. In the case of a subhuman with superior physical capabilities, fuel consumption is also moderate, so it is better to be prepared for 2 kg of food. Incidentally, a horse that pulls a wagon loaded with supplies eats ten times as much as a human. In other words, 10 kg of horse feed alone is needed per day.

By the way, the load capacity of a typical wagon in this world is about 500 kg. That is quite a performance. Thanks to axles and wheels made of magical materials. However, the speed of a wagon with a full load is slow. The speed is not much different from that of a human on foot.

If it rains, the road becomes muddy, the wagon cannot move properly, and the speed is even slower in areas where the ups and downs are severe. Furthermore, as mentioned above, horses are gluttonous. They need about 10 kg of food per day.

However, an air board or air bike can travel 400 km per day at cruising speed, and the supplies needed for such travel are only a few hundred grams of magic crystals.

Hard to understand? Then let me give you a concrete example.

Let’s say you want to deliver supplies to a battlefield 200 km away.

In this case, it would take a week for a horse-drawn wagon to go one way, and the horse alone would consume 70 kg of supplies each way. If it’s accompanied by three guards, they alone will consume around 28 kg of supplies in a week. That means they would consume about 100 kg of supplies on a one-way trip. Of course, after delivering the supplies, they would return to their base, so the consumption would be doubled to about 200 kg. That means that only 300 kg of supplies can be delivered to the front line.

Taking into account the one-way trip, which takes a week, and the round trip, 200 kg of supplies are consumed, which is barely enough to carry a day’s worth of food for only 150 people by subhuman standards. That’s right. This should give you a good idea of how difficult the task of resupply is.

Now, what would happen if this were done on an air board?

An air board capable of carrying 500 kg of supplies can cruise at a speed of 50 km/h. Unlike a horse, an air board does not need to take breaks, so it can run for eight hours, and the distance traveled per day is 400 kilometers. Moreover, unlike a horse-drawn carriage, the speed of travel is not affected by weather or road conditions.

In other words, if they wanted to, they could reach a battlefield 200 km away in half a day and return to a supply depot. Naturally, 500 kg of supplies would be delivered to the front line in its entirety. The only thing consumed in this way is a single magic crystal, which is produced inexhaustibly in the rear base.

The mechanization of logistics by air boards―or in this case, the magicalization of logistics?―I hope this explanation has made it clear to you how much benefit air boards provide to the supply chain. The air boards are really awesome.

By the way, my loading capacity is unmeasurable. There’s no limit so far. And I’ll create a field on the front line that can be harvested in a week at any time. I’ll create fortresses, towns, anything. And to top it off, I can travel hundreds of kilometers an hour on Grande flight, not to mention air boards.

Even just from a supply standpoint, if I were the enemy, I would do everything in my power to kill them or bring them on board!

Let’s return to the air bike.

・To achieve a cruising speed of 50 km/h and a maximum speed of 100 km/h, which is double that

・The speed must be maintained even when carrying up to 60 kg of luggage in addition to the passenger.

・The vehicle must be able to operate for a minimum of two weeks without specialized maintenance.

・Equipped with a function to maintain speed even when both hands are removed.

The air bike currently under development is required to have the above four features. As for the ability to maintain speed even when both hands are removed from the vehicle, they are considering shooting while moving, magic attacks, and eventually a cavalry charge with heavy armor.

I don’t think a cavalry charge is a good idea. Why don’t they just use a light machine gun and wipe the enemy off with it? If you want to use only the technology of this world, you could use a magic gun or a magic rifle that is under development.

A magic rifle is another version of a magic gun, a projectile weapon that shoots out magic rather than real bullets.

However, the development of this weapon has been difficult so far. The efficiency is not very good.

In the case of a magic gun, a single half-size magic crystal can fire approximately 500 rounds as long as there are bullets, but in the case of a magic rifle, the same half-size magic crystal can fire only about 10 rounds. It is said that the efficiency can be considerably improved by using larger and more complicated magic circuits or by using mithril silver alloy as the material of the barrel, but the manufacturing cost would rise if this were done.

A genius mage like Isla can shoot magic efficiently with less magic power by using complex formulas, but it seems to be a reality that it is quite difficult to make it into a magic tool.

“It can still run, can’t it?”

“Hmm. After the balance adjustment is finished, we will conduct load tests and endurance tests. Then we have to work on mass production. That’s a lot of work.”

“Well, it’s really fortunate that the basic technology has been established to some extent with air boards.”

“Hmm. As for the mobility equipment, I will ask Sir Leonard or Danan to arrange for a live subject.”

“That would be unfortunate, but you’ll have to do. In fact, if you think about it, it’s the subhuman soldiers who will actually use it…”

On second thought, even if it is adjusted for me, it may not be suitable for beastman and others. In that light, should we not be stubborn and leave the development to the beastman and other subhumans who might actually use the mobility devices?

“Kosuke’s sacrifice will not be in vain. At least the risk of serious injury is reduced.”

“Because I literally broke my bones…”

“Naisujoku?” [T/n: She wanted to said nice joke.]

“It wasn’t a joke…”

Because my body was seriously in pain, you know. Hahaha.

“Then I left the development of the mobility device to the beastman―Huh!”

Before I knew it, Isla’s hand was firmly gripping my clothes. Suddenly, I look up at the top of a nearby building and see some Harpies with smiles on their faces.

“Calm down. You’ll understand if we talk.”

“I will listen to you slowly in my room.”

Isla started to pull me with muscular strength that was not suitable for her small body, as if she had been strengthened by some mysterious power. Stop, stop! You’re stretching my clothes! I have other work to do; I have to work! If there isn’t one, I’ll make one! Please forgive me while the sun is still high!


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4 thoughts on “Goshujin-sama to Yuku Isekai Survival! – Chapter 252

  1. He should develop drive-able golems operated from the inside for military purposes, along the lines of walking tanks, hahaha. For those wanting to fight up close and personal.


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