Translator: SFBaka

Editor: Thor’s Stone

Kurt began his lecture next to the feet of the Huckebein.

「A Silhouette is basically manufactured by building a chest and waist frame around the MCS.」

Kou nodded. He knew of this by studying the structure of work Silhouettes and Unit 5.

「Hyoue-san made the most use out of the artificial muscle’s flexibility by modifying this basic structure. In other words, he didn’t build the chest as a whole. Instead, he divided it into right, left, and central blocks. He did the same for the waist. It’s divided into a right, left, and central hip block as well. Regular machines can only raise their arms straight upward, but Lanius is capable of bringing its shoulder backward.」

Kou was also already familiar with the block system. Voy complained that you’d likely have to replace the entire torso if a part of it breaks down.

「It’s the same for the waist. When you lower the machine’s hips, its posture stabilizes. This system enables the machine to twist its hips much like how humans do. Originally, it was also planned to get completely reinforced with artificial muscles. However, due to concerns about parts compatibility for repairs, that plan was scrapped, and only the minimum amount of artificial muscles required was used.」

「There’s also ease of maintenance to take into account.」

「Exactly. Furthermore, the arms and torso were supposed to be fully integrated, and that would result in the arms being non-replaceable. Hyoue-san eventually gave up on this idea as well. The production cost of Lanius also increased due to adopting a compound drive system.」

Something about that caught Kou’s attention. He then turned his gaze toward Huckebein.

「The limbs of Silhouettes employ a modular design, and they are standardized to some extent, right?」

「Right. Unless they’re employed in a completely unique or specialized machine. Both Lanius and Wurger use limbs with artificial muscles, but they can also use regular ones. Did you get some sort of inspiration, perhaps?」

「No. It’s still a vague concept for now. Once my thoughts have properly taken shape, I’d like you to hear them out as well, Kurt-san.」

「I’ll be looking forward to it then. I hope the Huckebein can serve as great material for your own bricolage. I and Hyoue-san were also inspired by each other’s designs when developing our respective machines.」

Kou asked a question to confirm something.

「 Have there been any drastic changes to the general Silhouette design through the years?」

「Unfortunately, no. After all, the technology originated 20,000 years ago. It can be said that it’s already been completely optimized. Parts compatibility, ease of repair, and maintenance have been brought to their logical extremes.」

「Yeah, I get that. As long as the hard points themselves aren’t damaged, you can easily replace a Silhouette’s arms and make it good as new....」

「That goes for the legs as well. In fact, as long as there’s a spare leg available, you can even connect it to your machine on your own. But since you probably won’t be carrying around a spare leg with you in a battle, you’d have to crawl to get to one in good condition first.」

「That doesn’t sound like much of an advantage.」

「Weapons need to be akin to warhorses that can withstand the rigors of brutal battlefields. Delicate thoroughbreds just won’t do. They have to be reliable enough not to break easily even after being subjected to plenty of abuse.」

「So they have to be able to withstand the brutality of warriors, so to speak.」

「Precisely.」

Kurt then proceeded to grumble a little.

「That’s where the troubles faced by us Development Engineers begin. Since we basically can’t make any drastic changes to the basic design structure, it’s quite difficult to come up with truly ground-breaking innovations. We’re currently relying on solely making improvements to the backpack modules. Replacing the limbs all the time also costs quite a bit of money. It’s especially easy to make out the difference in performance. Each material used for armor have their faults as well.」

「You can’t treat them the same as regular work machines anymore, right?」

「Yes. The high mobility machines we piloted earlier can be said to be closer to aircraft in build. If they used regular Silhouette limbs, their performance will drop noticeably, right? Even so, it’s not like they can afford to constantly replace their armor after suffering just one or two bullet holes.」

「So you still have to pay attention even though the machines can be easily repaired huh. How difficult.」

「It’s a peculiarity of the Nemesis warfront. Combatants usually operate as lone agents or mercenaries affiliated with Underground Forces. Their financial situations can be quite severe if they aren’t careful. If Okeanos, which implemented a universal currency system, didn’t exist, the Stones would have already dominated the Nemesis system’s entire economy by now.」

「I can see that happening....」

Kou couldn’t help but frown. Settling things by battling it out with weapons suited him more.

「Thanks to high-dimensional projection armor, melee weapons that are reinforced with Whis were also developed and proved to be very effective. Close combat is still generally avoided though.」

「Railguns and light-gas guns are now the mainstream, right? In terms of dealing impact pressure, projectile weapons seem to be unable to top swords, by I still don’t get the reason why until now.」

「Ceramics have a very high Hugoniot elastic limit. Steel is rated at 1.2 GPa (gigapascals). Titanium alloy is at 2.8 GPa. Tungsten is 3.8 GPa, and Ceramics are actually at 20 GPa. This is due to the bonds between atoms being stronger in ceramics compared to steel. However, due to their characteristic brittleness, they are less effective against slow-moving projectiles. This led to the development of composite armor. However, they are still unable to defend much against slow attacks such as a sword’s thrust or slash.」

「I heard that high-dimensional armor and weapons generate invisible thickness and weight values. I see. So it’s basically based on an image of hitting and breaking a ceramic plate.」

「Right. Even if the metal armor’s surface gets reinforced by saturating it with Whis, it’s still vulnerable to impacts such as those done by swords. Hence, as long as the Keres employ high-dimensional projection armor, melee attacks are still the most effective for dealing with them. You can also deal effective damage to them by repeatedly focus-firing on a single point with sufficiently powerful projectile weapons.」

Kurt brought Kou and Aki to another room.

It contained an assortment of shell projectiles.

Kou gave Aki a quick glance. This was Aki’s area of expertise.

Aki nodded with a composed expression. It looks like she’s decided to leave it to Kurt.

「You’re already aware that railguns and light-gas guns can share projectiles between them, right? Since penetration power is usually prioritized, the ones often used are APFSDS rounds. These rounds are composed of sabots containing dart-shaped projectiles made out of tungsten alloy. Once the projectile impacts its target at a sufficiently high velocity, both their surfaces will behave in a plastic fluid-like manner, allowing the long-rod projectile to directly penetrate the target owing to its higher density.」

Kou nodded in understanding. He’s already received a short introduction regarding this subject before. He did think a long name like “armor-piercing fin-stabilized discarding sabot” was a bit too much of a mouthful and hard to remember though.

A light-gas gun makes use of a large-diameter piston to force gas through a smaller diameter barrel in order to shoot out projectiles. Using railguns eliminates the need for gas injection and the accompanying storage costs, which also leads to a reduction of projectile unit price.

「This is a 120 mm shell. It’s basically the same size as the ones found back on 21st century Earth. This is said to be the maximum caliber that humans can carry and work with. Any larger than this, and they would have to be carried by Silhouettes.」

「Conversely, the use of larger caliber projectiles could become commonplace because humans rarely undertake such tasks without employing work Silhouettes now, right?」

「Correct.」

「The railguns and light-gas guns used in the Nemesis system are orders of magnitude different from the guns that were employed on Earth. Even if they don’t score direct hits, they would still cause tremendous impacts. This is one of the reasons why human infantry have entirely disappeared from this world’s battlefields. Here, see for yourself.」

Kurt pointed to a shell projectile that was as long and thick as a metal bat.

「Is this an autocannon round?」

「It’s currently the largest caliber autocannon shell employed here on Planet Asia. Its exact caliber is 60 millimeters. The autocannons that utilize these can fire at a rate of several hundred rounds per minute. They are quite effective against the ceramic armor that Keres commonly employ.」

「Whoah.」

Kou inwardly thought that no matter how thick his machine’s armor was, he really didn’t want to be on the receiving end of a rapid shower of hundreds of pointed metal bats made of tungsten.

「As long as you are within three meters of the impact point, you’d still get reduced to bloody bits even if you don’t get hit directly.」

Kou continued listening to Kurt’s lecture.

He learned what kind of performance requirements he should aim for when designing weapons as well as the proper ways of maintaining them, among other things. He found it a really rewarding experience.