Is This... a Bug? +45
I stared at the TP-C on the inspection stand.
A massive hunk of metal.
But in my eyes, its gaunt frame and bloated flesh were split apart and laid bare.
No wonder it failed...
The pain of the past three years flashed through my mind like a film strip.
The fundamental reason this project had been such a slog was simple.
We had gotten greedy.
The military had demanded absurd levels of protection, enough to stop North Korea’s new anti-tank missiles outright.
To meet that ridiculous ROC, we had had no choice.
We filled the interior to the brim with the most expensive, hardest silicon carbide, or SiC, tiles we could get our hands on.
The result was catastrophic.
We had barely managed to hit the protection requirements, but the unit cost had exploded like a bomb.
And the weight was so bad that if we put this into mass production as-is, the tank’s suspension would collapse under it.
Try to improve performance and money and weight blew up. Try to save money and performance fell short.
For three years, we had poured 20 billion won into chasing that impossible middle ground and ended up doing nothing but digging our own hole.
And then.
That blue line in my sight.
Following the flow of force, the answer came into focus.
We had been wasting effort in the wrong place all along.
When an impact came in, only about half of the internal tiles were actually doing the work.
The rest?
They were just sitting there.
Expensive excess material that neither absorbed impact nor provided support, occupying space for no reason at all.
These bits of dead weight... we could cut them away.
Remove the tiles that were just loafing around.
That would bring the cost down.
Then rearrange the remaining tiles at an angle, matching the slope of the blue line.
That would raise the protection efficiency again.
What I was seeing, honestly, I still wasn’t entirely sure about.
But one thing was certain.
If I built it exactly according to what I could see, the TP-C could meet the military’s ROC and still keep a workable level of cost efficiency.
And if I really pulled that off...
I’d be in a position to talk back to the company with my head held high.
Forced retirement?
Recommendation to resign?
I wouldn’t need any of that.
This would be my chance to prove myself.
If this was real, then I would...
“You done looking? Let’s go. Staring at it from here isn’t going to give you an answer.”
Song Bujang’s impatient voice cut through my thoughts.
I tore my gaze from the TP-C and spoke without looking away from it completely.
“Bujang-nim.”
“What now?”
“Let’s run one test.”
Song Bujang’s brow twisted hard.
“What? Now? After everything’s already done? When did HQ send down notice that they were cutting our budget?”
“It won’t cost money. Let’s just run the simulation again.”
I reached out and pointed to the side of the TP-C, where the ceramic tiles were layered.
“We need to change the internal design...”
“The design? Hey, do you not see that the thing is already packed full of tiles? What exactly are you planning to change in there? There isn’t any room left.”
“We can make room.”
Tracing the blue line with my finger, I went on, “We need to give it an angle. It can’t stay vertical like this. Roughly... about this much.”
I tilted my palm diagonally.
By eye, about 15 degrees, maybe a little more.
“If we lay it out at this angle, the effective thickness increases because of the angle of incidence. It’s much more efficient than taking the hit head-on.”
Song Bujang let out a dry laugh.
“Listen to yourself, Baek Gagwa. You know what you’re talking about? Sloped armor? You think anybody here doesn’t know that? But if you tilt the tiles inside a space that tight, the loading capacity drops. What about all the empty gaps that open up?”
“Doesn’t matter.”
“What?”
“The tiles in there now aren’t all necessary anyway. From what I can see, we can strip out at least twenty percent, maybe more.”
Song Bujang’s eyes went wide.
“Strip them out? Hey, this thing’s barely meeting protection standards even packed to the ceiling, and you want to take tiles out? Have you completely lost it?”
“Then we adjust the backing material.”
I did not back down.
Because I could see it.
That thick steel plate sitting there uselessly behind the ceramic.
“The rear support is way too thick right now. It was made that way because everyone was scared the ceramic would crack, so they overbuilt it like idiots. But looking at it now, that’s definitely overengineering.”
“...”
“Trim the thickness, then fill the space left behind by removing the tiles with more cushioning material, like a rubber composite. Then even if the ceramic gets thinner, it’ll absorb shock better.”
Song Bujang’s expression shifted in a strange way.
At first, he’d clearly dismissed it as nonsense.
But as I kept talking, the authority of a superior vanished from his eyes, and the instincts of an engineer started to rise to the surface.
Cut the expensive tiles to reduce cost.
Trim the heavy backing material to lower weight.
Then preserve performance by adding an angle to compensate for protection.
In theory, it was perfect.
The question was whether we could actually balance it at that delicate point.
“You... are you just talking off the top of your head, or do you actually have a basis for this?”
“I’ve been thinking about it ever since I was lying in the hospital.”
I grinned.
Whether I had spent all that time thinking about it in the hospital or not didn’t really matter.
What mattered was what the results looked like.
And what mattered most in this moment was that my ability seemed to be working for real.
Not only did it make sense to me, someone who had spent fifteen years living off machine work, but it also looked plausible and shocking to Song Bujang, who had worked at ADD.
“...Hah.”
Song Bujang ran a hand roughly through his hair.
His gaze flicked back and forth between the TP-C and me.
This was insane.
He was being asked to trust the optimized design that even the doctors at the Agency for Defense Development, ADD, had given up on, based on the wild ideas of a manager who had come back from the hospital with a concussion.
And yet.
“Give me a week.”
I drove the nail in deeper.
“Just one week. Within that time, I’ll revise the drawings the way I’m telling you and bring back the simulation results too. Judge it after that.”
“You think you can do that?”
“Yes. If the results are a mess, I’ll pack my bags without a word. Severance, whatever else, I’ll do whatever you tell me.”
Song Bujang said nothing for a long time.
Only the low hum of machinery filled the measurement room.
How many minutes passed like that?
At last, Song Bujang let out a deep breath and spoke.
“...I’ll give you access through my ID.”
“Thank you.”
“But don’t misunderstand. I’m not giving it to you because I’m expecting anything. The water’s already spilled. I’m just giving you one last chance to thrash around. So you can’t come back later and say I never let you try.”
He said it in a deliberately gruff voice, but I could tell.
A tiny flame had been lit in his eyes.
Instinct, from fifteen years as an engineer.
“That’s enough for me.”
I clenched my fist.
Thanks to Song Bujang’s decision, I had been given a real chance too.
*
Rattle.
The air felt heavy as I opened the office door and stepped inside.
After Song Bujang and I had disappeared, the employees had clearly lost the will to work and were gathered in little clumps, whispering among themselves.
Then it happened.
I met eyes with Jung Yunho, who had been peeking over the partition.
“Oh? Gagwa-nim!”
Assistant Manager Jeong sprang to his feet, brightening at once.
He ran over to me in a hurry.
“Are you all right? Song Bujang-nim suddenly took you away, so I was worried. Nothing happened, did it?”
The concern in his eyes as he looked me over was obvious.
I had taken him under my wing as my junior from the day he joined.
Ever since the company had turned into this mess, he had always seemed downcast, so seeing him lively again was a relief.
I gave his shoulder a light pat.
“What do you mean, nothing happened? I came back to work.”
“Huh? Work?”
“Move aside. I’m busy.”
I brushed past the bewildered Jeong Assistant Manager and headed for my seat.
Song Bujang followed behind me.
Every eye in the office turned to the two of us.
“Why is the Bujang in the manager’s seat?”
“Did something happen?”
Ignoring the team’s murmurs, Song Bujang tapped away at my keyboard.
Click, clack.
Once the administrator password was entered, the lock on the sealed security folder opened.
“Security folder opened.”
As Song Bujang stepped aside, the original design drawings for the TP-C filled the monitor.
A massive 3D model made up of thousands of components.
Over the tangled lines of it, blue trajectories only I could see overlapped in a chaotic web.
Instead of sitting down, I called over Jeong Assistant Manager, who was still standing there blankly because he had not caught up yet.
“Jeong Assistant Manager, come sit here.”
“Huh? Me?”
“My hands are slower than yours. Enter the coordinates I call out.”
Jung Yunho sat down in my seat with obvious uncertainty.
He kept looking between Song Bujang and me, as if he had no idea what was going on.
With his arms crossed, Song Bujang jerked his chin toward the monitor.
That meant to do it if I told him to.
“W-what do I start with?”
“First, select the ceramic tile layer. Cut thirty percent from the total count. Remove from the outer edge first.”
Jeong Assistant Manager’s hand hesitated.
“Thirty percent? Then the armor density...”
“No talking. Just delete it. We’ll look after that.”
At my firm voice, Jeong Assistant Manager looked nearly tearful as he moved the mouse.
The densely packed tiles on the screen vanished here and there.
A startled gasp came from Kim Soyeon, who was watching from behind.
Everyone else on the team was muttering in disbelief too.
It was no wonder. From their perspective, we were turning a perfectly good armor plate into Swiss cheese.
But in my eyes, this was just the normal process of removing excess fat from a patient with obesity.
“Select the remaining tiles. Tilt them 15.5 degrees on the Z-axis.”
“15.5 degrees?”
“Yeah. And tighten the spacing so they overlap each other.”
Jeong Assistant Manager’s hands moved quickly.
The tiles that had stood rigidly upright all tilted over at once.
Like fish scales, or like a tiled roof.
“Now we modify the backing material. Reduce the thickness to 15 millimeters.”
“You’re shaving 5 millimeters off a 20-millimeter layer? Gagwa-nim, are you really sure this is okay?”
“Change the shape too. The surface that touches the tiles shouldn’t be flat. Carve it into a serrated pattern.”
“S-serrated?”
Jeong Assistant Manager stared at me in horror.
“Gagwa-nim, if I model that, the mesh is going to break all over the place. And the geometry gets so complicated...”
“It has to be done. Otherwise the tiles will shift and crack everything.”
I pointed at the corner of the monitor.
“Here, sector 3. The tile layout is too neat. Shift it 0.5 millimeters to the left.”
“0.5 millimeters? Does that even matter?”
“It does. The load-bearing point changes once the tiles are tilted.”
Watching the point where the blue line bent slightly, I went on, “As it stands now, when it takes a hit, that edge will stab into the backing material. We need to offset it a little so the force can flow properly.”
Though he was still half unconvinced, Jeong Assistant Manager obeyed my orders under the pressure of my fierce pace.
Tap, tap-tap.
Keyboard strokes and mouse clicks rang out sharply, sometimes brisk, sometimes irritated.
About thirty minutes later, the screen displayed a new model, completely different from the existing TP-C and yet strangely balanced, though bizarre.
“Phew... that’s everything, at least.”
Looking exhausted from the frantic concentration, Jeong Assistant Manager stretched both arms out and spoke.
I immediately launched the simple built-in analysis tool.
It was a function that could check changes in physical values immediately, even if it wasn’t a precise simulation.
“Let’s see the result.”
I pressed Enter.
The progress bar in the center of the screen filled rapidly.
Song Bujang uncrossed his arms and moved in close to the monitor.
The rest of the team held their breath too.
Ding.
The result window appeared.
The first thing that caught my eye was the reduction value highlighted in red.
Total Weight: -12.4%
Estimated Cost: -21.8%
“Wow...”
Kim Soyeon let out a gasp.
“The weight dropped by 12%? My God.”
At this level, it was like giving the tank’s mobility wings.
And on top of that, a 21.8 percent cost reduction.
Just the composite armor package for one tank already cost several hundred million won.
Cutting that by more than 20 percent meant that, across the full production run, the company’s margin would become astronomical.
But Song Bujang’s face still hadn’t loosened.
The most important metric for an engineer was still left.
“What about protection?”
His voice was low.
“If we just made something light and cheap that falls apart, it’s meaningless. Show me the protection numbers.”
Without a word, I clicked the effective protection efficiency tab.
A graph appeared on the screen.
The efficiency curve of the existing TP-C model was shown as a gray dashed line, while the model we had just modified appeared as a blue solid line.
The gray dashed line hovered just barely above the baseline of 1.0.
But the blue solid line...
Protection Efficiency: 1.15
It had shot well past the benchmark and was climbing upward.
“1.15...?”
Song Bujang’s pupils shook violently.
Protection had not fallen.
It had gone up by 15 percent.
We had reduced the material, reduced the weight, and made it stronger?
He looked like he thought the result was physically impossible.
“This... isn’t a bug, is it? The simple analysis tool didn’t calculate it wrong, did it?”
Song Bujang tapped the monitor in disbelief.
“Even accounting for the sloped armor effect, this makes no sense. You removed dense steel and packed in rubber scraps, and protection still came out at 1.15? That’s not physically possible.”
“It works because it’s not just blocking the hit, Bujang-nim. It’s burning it out.”
“What?”
“The rubber composite doesn’t just absorb shock. It induces impedance mismatch between the ceramic and the backing material.”
I pointed to the waveform on the graph.
“The moment the shell makes contact, the shock wave will travel backward. But when it hits the rubber layer, the wave speed changes abruptly. In that process, the shock wave is scattered and reflected, and the ceramic gets shattered into much finer fragments.”
“...!”
“In other words, we’re forcing the penetrator to burn through all its kinetic energy breaking the ceramic before it even gets through. Compared to just brute-forcing the thickness of a steel plate, the energy dissipation rate has to be much higher.”
Song Bujang’s mouth parted slightly.
A design that turned incoming force against itself and made the shell wear itself out.
Theoretically, everyone knew the idea.
Actually balancing the composition ratio in a real design, though, was a brutally difficult skill.
“You... you knew this composition ratio going in?”
Song Bujang’s voice trembled.
“It was just a hunch.”
I shrugged.
Calling the answer shown by the blue line a hunch was pretty convenient.
After a short pause like that, Song Bujang’s gaze shifted to me.
The suspicious look he’d been wearing only moments ago was gone, replaced now by eyes lit with cautious hope.
“Baek Gagwa.”
“Yes.”
“Let’s run a full analysis on this.”
There was force in his voice now.
“Not the simple tool. We need to run it properly on the analysis team’s supercomputer. If these numbers are real... then we can turn this around.”
He immediately pulled out his phone.
His eyes flashed fiercely as he hit the speed dial.
“Yeah, it’s me. Put the structural analysis team leader on. Call a meeting. Right now.”
After hanging up, Song Bujang looked at me and grinned.
“Come on. Let’s go see whether the numbers you made actually hold up in the real world.”