Building Bertha: A Love Story

[Rusty]

Some people believed that armor was the king of the battlefield.

Rusty knew better.

Traditionally, artillery was the king of the battlefield. Artillery could make or break an army.

Utlima Ratio Regum, the final argument of kings.

The Force fights on the side with the best artillery.

The pithy sayings went on and on.

In the strictest sense, the Shard knew this to be true, even in this day and age. A good shelling could wreak havoc on an opposing force, and shields had little to nothing to do with it. If you carried enough shielding with you to stop a 155mm shell, you were probably too slow to be of any use. If you tried to use speed and maneuverability to get out from under the shell, you were still hosed, because one shell always brought friends.

Yes siree, artillery was the real winner of wars, but there was something to be said for direct fire too.

Handheld missile launchers and recoilless rifles had fallen out of fashion in this modern age of shielding and super advanced armor, and Rusty intended to change that. There was no reason why a foot soldier should have to cower in fear at the first sign of armor. There was no reason why a man portable weapons system capable of potting even the most powerful vehicles didn't exist, save for the fact that no one thought it was possible.

That was why the Shard had come up with the idea of Bertha. He didn't want to just level the playing field for troops on the ground, he wanted to flip it upside down. Let the crews in their walkers and hovertanks cower in fear inside their metal coffins, waiting for the inevitable to roast them alive. It was time to put the fear of the foot soldier back into their lives.

 

[Rusty]

The basic idea Rusty decided to go with was the recoilless rifle.

The design was simple.

The main launcher was a relatively simple tube. It featured a simple durasteel sleeve wrapped in a carbon fiber shell that provided extra strength and rigidity. It was about a meter long, and flared at the back end. The durasteel tube was rifled, in order to impart spin to the projectile.

The cartridge of the recoilless rifle is perforated by design. The projectile is inserted into the back of the rifle and locked with a half turn. When the weapon is fired, much of the hot gas the results from the explosion is used to propel the projectile forward, but a fair bit is directed backwards. By directing a portion of the expanding gas backwards, much, but not all, of the recoil is cancelled out.

One of the most important things anyone who was experienced with the things will tell you is that recoilless rifles aren't. They kick like a mule, but the vented gas cancels out enough that the act of firing is survivable. Thus, a foot soldier can carry a weapon as powerful as a traditional artillery piece.

There are two downsides to this system. Firstly, by using some of the gas to cancel recoil, that gas cannot be used to propel the round forwards. This reduces overall range. Secondly, the resulting backblast is potentially fatal to anyone within three meters directly behind the weapon. On top of that, firing in an enclosed area like a bunker or a room would kill everyone within it.

Rusty considered including some of the backblast mitigation techniques, but most of those necessitated making the weapon single use, as they required destructive techniques. Rusty wanted his launcher to be reusable.

Most recoilless rifle designs compensated for a lack of range by using increased payloads. Though recoilless rifles are technically considered artillery pieces by bore, they pack a heavier punch than a traditional artillery round. This is because the act of firing exposes the firer, so when engaging vehicles, they typically only get one shot. If they don't take it out on the first shot, they typically ended up as ash on the wind.

Rusty was going to go a different direction. He was going to go in a radical direction that, to the best of his knowledge, no one had pursued in recent memory. It was going to take some work, but he figured it was worth it.

 

[Rusty]

Generally speaking, there are two ways to defeat armor on a vehicle.

The first is to blast a hole in it using explosives. This is the most popular way to go about it, because explosions are startlingly easy to engineer and control. One can make a bomb out of far more than most people realize, and someone with military grade explosives and a lab can design one hell of a bomb. Shaped charges in particular are popular, as they create a molten jet of copper that can easily burn through some fairly serious armor.

Most recoilless rifle rounds depend on explosives to get the job done. In fact, they typically use more of the stuff than artillery shells of a comparable bore, in order to make up for the lack of range or velocity.

The second method is to use a dense penetrator traveling at insane velocities to brute force through the armor. It is, oddly enough, the preferred method for defeating heavy armor. The penetrator method often relies on using fairly exotic materials, such as depleted uranium or tungsten, to get the job done. The problem with this method is that it usually requires a very large, very stable firing platform in order to work. The forces generated are tremendous, and there simply hasn't been a man portable platform capable of generating enough energy to penetrate heavy armor.

That was the problem Rusty set out to solve. Any old idiot could make a recoilless rifle. He wanted to make a hypervelocity recoilless rifle.

 

[Rusty]

The real engineering challenge here would be the projectile.

Rusty didn't have a lot to work with here in the way of mass, at least not when compared to a traditional discarding sabot penetrator. That meant, if he wanted to bring a comparable amount of force to bear, he'd need to increase velocity dramatically.

That implied a two stage device. The powder charge that initially launched the projectile would be the first. It would get the round going in approximately the right direction and impart enough velocity to make the second stage meaningful.

For the second stage, the most obvious solution was to strap a rocket on the projectile. Rockets were simple, after all. A solid fuel rocket doesn't have much in the way of moving parts, and if you get everything right, there's not a whole lot to go wrong. The downside was that rockets had to carry their own oxidizer, which reduced the overall weight of fuel they could carry and thus limited the burn time.

He briefly considered adapting repulsor technology to generate the thrust, but almost immediately discounted it. The technology was fine for some applications, but there was just too much to go wrong.

Finally, he settled on a classic (some would say antiquated) design: the ramjet. Most jet engines relied on internal turbines to compress the air. This allowed them to operate at low speeds, but placed an absolute limit on the upper range: if the vehicle went too fast, it would wreck the compressors.

Ramjets, on the other hand, relied on internal geometry to compress the air. Unlike a normal jet engine, which could operate while sitting still, the ramjet had to reach a certain velocity before it could function. But once it hit that velocity, the speeds it could generate were incredible. The only limitations were the fuel supply and the mechanical strength of the airframe.

Rusty was reasonably certain he could get this thing to work, but it would take some engineering.

 

[Rusty]

Once upon a time, working with osmium would have been quite difficult for Rusty. The metal was nearly impossible to melt, incredibly tough, and even getting it was somewhat difficult.

The upside to his recent expansion was that he was able to upgrade his workshop considerably. No more hand forging the stuff, not for this Shard. He still did most of his blades by hand, as he liked the work, but when it came to precision stuff like this, he was more than happy to put his new fabricator to work.

The penetrator, as you might have guessed, would be a slender osmium spike roughly 10 centimeters long and 1 centimeter in diameter. The rest of the projectile would basically be the propulsion system.

The spike would make up the core of the inlet body. While it was the perfect shape for penetrating armor, it was exactly the wrong shape of the inlet body, so it would be surrounded by aerospace grade durasteel that would be able to stand up to the stresses of the airflow, but would break away when the projectile struck something solid. The penetrator spike wouldn't be held in by anything more than friction, but the tolerances were tight enough that, once everything was fitted, it wouldn't be able to just fall out by accident.

The outer nacelle would likewise be made of aerospace grade durasteel. The stuff was lightweight, but extremely sturdy. It had no flex to it at all, which made it a bad choice for blades, but was perfect for this application. The first half of the body would double as the fuel tank. Fuel would be sprayed into the combustion chamber via four nozzles. Rather than relying on a fuel pump, it would be force through the nozzles by inertial. They would be capped for storage, but when the round was armed, the caps would be removed.

Because of the inertial fuel delivery, the projectile couldn't be allowed to spin. Instead, covered by a discarding sabot that would also plug up the rear of the projectile until it cleared the tube, were fins that would bite into the air and keep it relatively straight.

The total length of the projectile was about 25 centimeters.

That was long by recoilless rifle standards, but the actual weight wasn't more than the average HEAT round.

All the data was inputted into the fabricator. It would machine all the parts and put them together. All Rusty would have to do is fuel up the projectile and test it out.

Meanwhile, it was time to design the other rounds.

 

[Rusty]

At the end of the day, Bertha was still a recoilless rifle, and as pretty as her party dress was, she'd still need other outfits.

The most basic round for any weapon along these lines was the HE, or High Explosives round. It was basically a standard artillery shell stuffed with more than average boom. Its purpose was to destroy buildings, light armored vehicles, and other relatively soft targets. It was a versatile round, a true case of "jack of all trades but master of none." The HE round was a workhorse, not a thoroughbred.

It could be made infinitely more versatile with the advent of the multipurpose fuse, however.

The standard setting was Contact. It was fairly self explanatory. The round would hit something, and the fuse would set it off, resulting in a large explosion on the surface of whatever it hit.

The second setting was Proximity. A small Doppler radar in the nose would detect when the round entered the proximity of the target and would explode at a set distance. That set distance was usually 10 meters, but if you had a hex-head screwdriver on hand, you could dial it up to twenty or down as low as three. The primary purpose of this function was to allow for limited engagements against slower aircraft, as an explosion in near proximity could definitely destroy one if it hit just right. At the very least, the pilot was likely to soil themselves. Clever troopers would realize that it could also be used as an airburst weapon against troops behind cover. Set the fuse for three meters and then launch it above a berm or a trench and it would rain down hellfire on the enemy soldiers.

The third setting, delay, was most useful against buildings and light bunkers. On impact, the round would wait a split second before detonating, allowing the projectile to travel through thin walled buildings. By blowing up inside the building, it would do a lot more damage than it would have by detonating outside. Smaller structures would often be knocked flat, and even larger or reinforced structures would be gutted to a certain extent. It might not level a skyscraper, but anyone within a few dozen meters of the blast would be too dead or injured to care.

 

[Rusty]

The next round was more of a specialized thing: The High Explosives Anti Tank, or HEAT round.

The basic premise was simple enough: it had a large explosive charge, but it was also a shaped charge. It was designed to impact against something hard, like an armored vehicle. The explosives would go off, sending a self-forging copper projectile screaming through the armor of the target. Once it got inside, it cooled down, but it was still going way over the legal speed limit, so little bits of copper went bouncing around, and through any poor unfortunate souls that happened to be inside.

Meanwhile, underneath the casing and wrapped around the explosive charge, was notched durasteel wire. While the shaped charge dealt with the vehicle itself, the shrapnel generated by the rest of the weapon would scour the area immediately around it, poking holes in any troops that happen to be hanging around it. It had an effective kill radius of about three meters, which was nothing to sneeze at, but wasn't great by grenade standards.

And though the shaped charge was pretty good about taking out light to medium armored vehicles like troop transports and self propelled artillery pieces, it wouldn't do more than piss off a main battle tank unless a lucky hit took out the engine compartment.

In short, the HEAT round was specialized enough to be good at a couple of things, but it wasn't the best choice for either of them. It was best used against light armor with dismounts, where it stood the chance to do the most damage. For that purpose it was more than adequate. And besides, sometimes the objective wasn't to kill everything, but to scare them enough to withdraw.

 

[Rusty]

The next and final round Rusty was designed was the canister round.

The idea was simple: Bertha had a large bore and a lot of powder. So if you loaded her up with ball bearings instead of high explosives, she made for one hell of a shotgun.

That was basically what a canister round was: a giant shotgun shell. Then the round was fired, the blast would sent the canister screaming out of the barrel. After a few meters, the canister would split, sending the shot flying everywhere. This was not a long range solution, as it would be difficult to accurately target anything beyond about 150 meters.

For shot, Rusty decided to go with 1.5 centimeter diameter tungsten/durasteel ball bearings. The canister could effectively contain 500 of the things, which was nice. It also should be able to handle thin walled buildings and obstacles such as razor or concertina wire.

Canister rounds were one of the few rounds that could be useful on a ship, as they could effectively turn a corridor of soldiers into paste. The primary downsides, aside from the potential to be killed by backblast, was the fact that there was a very high chance of the ball bearings bouncing back towards the shooter, or else penetrating outwards through the hull. This wouldn't be a problem on larger warships, but on a lighter freighter or transport? Big, big problem.

But hey, what's the point of life if you're not willing to take a risk every now and again?

 

[Rusty]

For the obvious reasons, Rusty wouldn't be able to test out the weapon live in his shop. Instead, he had to rely on computer simulations.

Everything looked promising so far.

He was using an 80mm bore, which meant the rounds had some legs on them. By his calculations, the standard HE round could reach out and touch someone at about 1100 meters, maybe further with some kind of mount. The HEAT round was a little heavier, but it was still good for 900 meters, and the Hypervelocity Penetrator (HVP) round...

"HOLY [bleep]!" he exclaimed as he read the readout.

There had to be a mistake. He knew the ramjet was potent, but there was no way it could do that.

Rusty ran the numbers again.

The exact range was, well, theoretical. It would never get out that far, so he slapped 1500 meters down as the effective range and left it at that. On a sufficiently small planet, the [bleep]ing thing could hit escape velocity, no problem. On standard gravity, well, it was line of sight. Literally, line of sight. If you could see it and it held still long enough, you could hit it. That wasn't the same as being able to kill it; after about 3000 meters the air resistance would slow it down to the point were it wouldn't be able to punch through heavy armor.

And hell, the 1500 meters probably wasn't sandbagging too badly; even at the speeds the round traveled, that was a long way to go, and trying to aim accurately at something that far away that was moving would be difficult. So 1500 meters it was.

Now it was time to wait for everything to finish fabrication.

 

[Rusty]

When Bertha was finally finished, Rusty felt like maybe he finally understood what it was like to be a proud daddy.

She was heavy, coming in at about 8 kilograms unloaded, and at 1 meter long, she wasn't exactly short either. Her olive drab pain scheme wasn't glamorous. She didn't have any fancy switches or buttons, no real moving parts either. It would be hard to coax any impressive metallic noises from her, like people always seemed to in the action holos.

Rusty didn't care.

She was beautiful.

It was about that time Koko walked in from the office, stack of paperwork in hand.

"Hey boss," she said, turning the corner to find the elder Shard cradling Bertha like an infant. "What do yo-OH MY GOD, WHAT THE HELL ARE YOU DOING?"

Rusty turned around, swaying gently as he patted Bertha on the side.

"Shhhh," he replied. "She's sleeping."