Fantasy Railgun

I'm running a fantasy nation builder, and one player figured out a way to create a railgun. The random event table gave him rare resources and he got especially magnetic rocks that conduct electricity well depending on their temperature. The nation he's building has creatures that can generate electrical current like an electric eel. By placing the rocks in a line and charging them in sequence he proposes to fire a high velocity projectile.
Keep in mind this is a fantasy setting.
I'm trying to let the players have as much free reign as possible, but this just seems somewhere between ridiculous and overpowered. On the other hand, it's creative, interesting, and could bring some interesting flavor to the world. I've denied other players things before, like a perpetual acceleration machine because it could break the planet, but I don't like restricting them too much.

What do?

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Make the railguns good but prone to failures and not overpowered in damage?

Make the railgun good but the ammunition needs to be said special rare magnetic recourses. making it a few shot at most.

Point out to him that the timing on a railgun's circuit is actually really difficult to pull off, and that even with modern computer technology it's still pretty hard. To do this with analog systems would take superhuman precision and control, especially with the inconsistent power output resulting from using animals instead of proper electrical transformers. If he wants a railgun, he'd better create a custom spell to manage it. And once that's done, the railgun can be limited like you would access to any other spell. I don't know what system you're using, but whether spell slots or mana pools or just high difficulties to cast powerful spells, you can limit its use that way.

That could work pretty well. Thanks.

Good ideas as well.

Make the rocks fucking heavy and building the railgun annoying.
Make the projectiles very powerful but require a long time to charge and everyone can see it coming for a mile away while it is charging up (think Dragon Ball kamekameha). Since everyone can see it and you can't aim it precisely because the entire thing is too heavy and awkward, it have very very low accuracy.
So basically it is a powerful version of a trebuchet, great for destroying buildings that can't run away but extremely shit at killing things that can run away.

Good idea. He has very poor mastery of other metals and few sources of iron to make the steel mount for the gun so using it purely as a siege machine makes sense.

Have the creatures get tired from supplying so much power. Maybe give him one guaranteed shot a day and then make him roll for any more.

As proposed, it could work.

However, good fucking luck timing the discharge properly. And just placing the rocks in a row won't do anything. A railgun requires two rails to function, and precise shaping/working of the material. Can he forge the rocks? Or is he talking about a coilgun instead of a railgun?

Coilguns work by generating magnetic fields in sequence, but that also requires properly shaping the rings on top of the already mentioned timing issues. In short, he better be ready to dump a lot of time and magic into building the one gun when he could have dozens of ballistas or gunpowder siege weapons of comparable power.

Also, takes a shitton of power to fire off a railgun or coilgun. More than a few tanks of eels-worth.

It'd probably be cheaper and easier just to have him build a peasant railgun

Point out that he's confused railgun and coilgun so that he feels bad about himself and gives up.

a certain magical railgun

Good point. Gotta use the right terminology.

Certainly.

Except this isn't D&D. Physics actually work in this setting (most of the time).

Go the full length. Make it a legit, outright railgun. Massive power, capable of piercing practically anything, and an insane range. It can legitimately one-shot anything. (peak of modern technology vs fantasy, yeah tech wins).

But then include everything a railgun entails. And that is a mechanism which requires constant expensive repairs. Modern railguns can fire about two to three shots before needing full repair, if not outright replacement.

If he's smart, he'll realize there's no way this can viably be used constantly. Not with how rare materials are. So his empire or whatever now has a trump card. One final weapon, with extremely limited use that finishes off anything that was so overwhelming as to force its use.

Remember kids, modern technology can always be freely put in fantasy. Just remember to put in the sheer cost of it which fantasy can not compensate for, whereas modern day can.

Why is a rail gun assumed to be especially powerful, or high velocity?

There is nothing inherent in the design of one that make them super high velocity or super penetrating - this only appears to be the case because railguns are only of interest in reality for doing what a conventional gun cannot. Which is shoot things very, very, very fast.

Making a very low velocity railgun that fires a really massive projectile, sort of like an electric catapult or an early gunpowder mortar, would actually be far more reasonable with the technology seemingly available. The soft acceleration would also be very useful for flinging pots of incendiary material.

Science! Super conductors can move objects at HIGH VELOCITY due to an avoidance of friction plus high acceleration!

Then relativistic weapons take over once it is high enough velocity. And if you don't know what relativistic weapons are, well read this:
futurewarstories.blogspot.com/2014/11/fws-topics-orbital-bombardment.html

Basically, that section on kinetic orbital projectiles? Those are relativistic weapons. Railguns replicate that effect, or at least closely, without needing to go off into space.

Or in short, imagine getting hit by a mini nuke. Without needing a nuke.

And said mini nuke can not be intercepted viably.

Anything else, user?

Oh, and to cap off a final point.

Mini nuke which can not be stopped versus some low-velocity incend which can be stopped.

Guess which one wins, user.

Answer: The mini-nuke.

>Relativistic
>Superconductors

Wait when did this become about star wars? Super conductors do not eliminate "friction" either. A superconducting railgun would still have friction because it still would have a sliding armature.

>mini-nuke

No. Not even close. You realize that energy is conserved, right? To get a "mini nuke" you need a mini nuke worth of energy. Shooting a tiny rock very, very, very fast is actually not some incredible super weapon.

>using science to make a railgun
>not just a ton of peasants and a 10 foot iron rod

They come god-damn close to doing so. And 'sliding' armature? Railguns are not the classic guns you're used to. Maybe gauss weapons, but this is an entirely different level of electromagnetic funtime. And no, Star Wars is not what this is about. But I have to provide simple examples on Veeky Forums after all, so there you do.

And holy damn user, shooting a rock very fast is indeed a super weapon. Even if we cast off all of this, and go back to the basics of literally throwing a rock, tell me what hurts more? A rock hurled full strength at high speed? Or a rock gently tossed that goes about a foot per sec for two seconds?

Yep! It's the rock going at HIGH SPEED.

Relativistic weapons user. Learn about them, learn about the physics behind them, and learn why kitty litter fired from off-planet at a planet is one of the deadliest weapons to ever exist.

Kek.

I appreciate you user. And yeah, I'm the science user with the link to Future War Stories.

But I appreciate humor. Many keks.

>Except this isn't D&D. Physics actually work in this setting (most of the time).
To be fair the peasant railgun just requires a really lax DM. The fact you're trying to find out how to reasonably incorporate a railgun/coilgun into your world shows you're at least not that lax.

Seriously who would ever assume that the passing is happening all in the same 6 second period? The readying of the passing obviously means their reaction comes when the stick is passed, not at an arbitrary time limit. Christ I'd slap a player

user, we're not talking about superconductive coils in vacuum. We're talking about slightly unusual magical rocks in a fantasy setting. Even if they were capable of producing a fucking absurd field and a really long barrel, they might be able to get up to a ton of tnt worth of energy in the projectile, but they would still need to use up that much energy in the device, which is possible nowadays, but would require some literal magic to do so in a pre-industrial society.

Convenient they have magic in that fantasy pre-industrial setting......................

....wait, something's wrong here.

> especially magnetic rocks that conduct electricity well depending on their temperature
but the whole purpose of the electricity is to "turn on" the magnetic effect on demand. If they're constantly magnetic and in a single direction, how do you use that in a railgun?

Electric Eels can generate current, but any animal that does so does it at inconsistent voltages and currents. You'll need to feed whatever they release into a battery for proper control, and battery tech is a HUGE stone wall techwise for a lot of things. Timers too.

First off, if you're going to be a fag and use ellipses, only use one at a time.

Also, how much effort do you think it would take to create a magic item that imparts several thousand kiloJoules, and how much more efficient would it be to just have a giant version of magic missile, or fireball, or create food and water, or basically any other use than someone's hobby project?

Do you legitimately not understand the concept of constant energy?

At a constant energy a relativistic projectile isn't just going to be tiny, it is going to be a literal particle. One gram traveling at .998 c has over 1.4 billion megajoules of energy.

You are gonna need a lot of electric eels. Like a lot. Trillions maybe.

This is roughly equivalent to 280 billion kilograms traveling at a more leisurely 100 m/s.

Now if 280 million tonnes of rock fell on you, do you think it would hurt?

The player has some good rune magic though. Using his people to charge it up and the runes to coordinate the coils would work. Not that I'm telling him that, he'll have to figure it out on his own. He's used runes cleverly before though.
I've had more fun hosting a builder than I've ever had playing a game. The players come up with the most dastardly things. Every time they look like they're on the ropes they come up with something crazy that I never thought of but would totally work. Right now they're engaged in a giant cold war planning their first strike. The more aggressive players prey upon the minor factions and keep away from each other, but somebody got caught spying is now suspected of magical terrorism.
Next time I host I'll try and get players that don't know each other personally though, it makes weird dynamics.

I wouldn't know magic to energy conversion rates user, but OP implies they have enough.
Once more, I don't know magic to energy conversion. OP has implied "enough to get the thing going"
Also, you kinda justified my argument on relativistic projectiles, from what I can read. I have really have no idea how electric eels got in here.

If you're ok in principle with his idea I'd just keep in mind that electromagnetic cannons does not necessarily mean modern hypersonic rail gun or whatever. It could just as easily and more likely perform worse that a cannon or catapult.
I would advise him to take advantage of the relatively steady and gentle acceleration to lob fragile projectiles. IE pots of Greek fire. Would also be advantageous naval wise as no gunpowder to go boom.
Basically just make it equivalent to something you're comfortable with, then give it some advantages and disadvantages to make it unique and cool.

Also nation builders have always interested me, any chance you could upload the rules you're using or whatever material for how you run one?

If they're willing to put in the thought to make it work, then all power to them. I'd personally stick to just the EM catapult, personally, and save the fancier stuff for the thing you're launching. Delayed Blast Fireball (or equivalent) on the thing being launched could be fun, and the smaller size needed means you could covertly set up for a siege instead of having to develop the railroad just to cart your new superweapon around.

Basically, I'm suggesting
>I backstab him with the mortar

Are you slow or something?

All you "argued" is that if you put an unimaginable amount of energy into a projectile, it will be very powerful. This is like saying if the moon fell on you, it would be very heavy. Or if you fell into the Sun, it would be hot.

At a reasonable energy level a "relativistic weapon" shoots atoms. Not bullets. And atoms do not behave like bullets. At all.

We can already shoot relativistic particles. They are not impressive as weapons.

I love how everyone steers clear of me and user going on about something that is good for /k/ at this point.

I.....eh......look what I argued is that thanks to the science behind relativistic weapons and that railguns operate on a similar function, a basic piece of metal can be easily weaponized. An object at high velocity can penetrate most objects, and with some mass on it, you can get massive impacts. Imagine recreating the effect of an asteroid, with a basic piece of metal fired from a railgun. You no longer need a moon, because you can recreate that effect from a rock. Or kitty litter, but that's an Atomic Rockets reference. Anyway, relativistic weapons would normally be fired from space. But the value in a railgun is that it could come close to such an effect without needing to be in space. Happy, user?

If you have the ability to make directional lightning, and you do because you are in a fantasy setting, there really isn't any reason to have railguns.

Just make directional lightning guns, user.

Give me a sec and I'll throw together my documents. A lot of it is just imagination and time. When the game ends I'll be putting all of the information we've created somewhere. This builder is meant to create a fully fleshed out setting to host a campaign in or make a story in since about half of my players like to write.

Pst OP.

How you liking the viability and power of railguns argument in the background?

Enjoying quite a bit. I'm always glad to see an argument. If the thread made up its mind either way immediately it would point to there being a problem of some sort or my post being boring.

But anyway, dissenting user seems to have left. So as I have mentioned earlier, have that power exist. But make it nearly impossible for use beyond a shot or two. The first modern railguns broke on in one shot due to stress.

Keep that aspect in, and balance!

What if...

Take a 50ft long steel tube, have a sealable hatch at the top you could insert a projectile and a cap on the bottom

Using magic you create a portal at the bottom, the exit portal being at the top. You then use more magic or science to create a total vacuum within the pipe. Stand the pipe on end and begin accelerating the projectile.

With no air to create friction and terminal velocity, it will continually fall, going faster and faster, until you open a second portal directly above the bottom one, with that exit portal being piinted towards whatever you wish to obliterate

This is Portal. As in the game, Portal. You literally use this mechanic (kind of-differently applied, but same basic concept)

I'm not mad. I'm just legit surprised that made its way in.

I had a player propose this and immediately told them they are "not allowed to hold the planet for ransom".

Can they hold the DM for ransom?

A third of them know where I live, so I guess they could if they really wanted to.

Well shit user.
Get me in on that, I need my share of money for creating the idea to hold you ransom.

drive.google.com/drive/folders/0Byxd0FpiZANbcWtoamY3SklRc2s?usp=sharing
This folder has a bunch of my planning docs, a few example docs from the current game, and a modified version of your intro doc. Have fun and excuse my lack of editing.

OHOHOHOHOHOHOHOH
I'M GLAD I STAYED HERE AFTER FINISHING MY ARGUMENT FOR WHY RAILGUN IS POWERFUL

AH THANKS MUCH user

And now that my caps lock is gone, oh boy I feel sorry if a player ends up pulling major civil war three times in a row.

I've had some very funny rolls.
One player said "user, you can give me a bad event, I want one, bad events give me a chance to thrive in the face of conflicts and turn a negative situation into a good one". I rolled and he got "re-roll twice" and then got a civil war and a monster infestation at the same time. He's never asked for a bad event again.
I have another player who didn't get a bad event until turn 5.
Another player got "re-roll twice" and then got "rich resource" twice.
4/5 of the players rolled elite troops, and only half of them had to pay for them.
It's a madhouse.

Mazin'

Share some stories on Veeky Forums at some point!
Put links here when you do though, cause I gtg!

user's point was that if you want a relativistic weapon that replicates the damage of a crashing moon, you need to put a similar amount of energy INTO the weapon as you'd spend deorbiting the actual Moon.

It's a bit like the Death Star. One of the Empire's admirals took one look at it and said "with the resources and manpower it took to build this monstrosity, we could have made a hundred thousand Star Destroyers and ruled the entire Galaxy."

make it really heavy and loud. Like farts turned to shitwhich is like a real railgun

Remember the biggest flaw to the railgun (other than the massive amount of power it draws) is the HEAT. Real life railguns have to have their rails replaced or be made out of heat resistant materials.

My suggest would be to replace the stones often or give them a drawback like fires 2 shots then it overheats and has to cool down for awhile

Let him do it, but I'm a fucking sucker for railguns and always will be.

That 'charging in sequence' bit makes it a coilgun analog, not a railgun. For this to work, he has to drill holes in all the rocks. And if that's surmountable, there's the problem of the rocks trying to tear themselves apart by magnetic forces. And if THAT's surmountable, there's the hard AF problem of switching current correctly as the projectile travels down the barrel. Let him try to do that with eels.
The projectile itself also has to have some magnetic properties which I'm too lazy to explain.

An actual railgun has another set of problems: the rails pushing each other away with incredible strength, the abrasion of the rails (early experimental railguns were good for ONE shot only), the arcing between the rails.

Both devices would also have a problem with heating.

>By placing the rocks in a line and charging them in sequence he proposes to fire a high velocity projectile.

Unless he could perfectly smooth and line up the rocks and thier magnetic fields a bunch of chunks of loadite arent going to make a railgun.

Id let them do it, but it would be a rare thing maybe one per well equipped army, and a couple mounted high in ever major city.

Unless youre playing the highest of high magic (In which these would be redundant anyhow.) your PCs shouldnt be able to just whip a bunch of rare earth magnets into functional mass produced rail guns easy enough to equip an army or even a unit.

Also logistics of keeping these things in ammo, and preventing constant attempts to steal one or the plans, maybe any major military action against the PCs involves major raids against the places that supply the materials? Or the materials in transport? Treat them like a major strategic assets not an assault rifle and that should keep the PC empire suitably paranoid to just whip them out to solve every and all problems.

What you described is a coil gun, known for being bult by anyone and not going faster than a regular gun. Punish his hubris with scientific knowledge.

There is so much that goes Into an actual coilgun that neither you nor he obviously know. If he wants to try to do something this dumb, he better know how to make it work in real life. I dont think he does. In fact I think all either of you know is hurrr magnets + electricity make shoot

Which is such an over simplification it's rediculous

What about the timing? What about heat? What about the fact that modern coilguns made of super materials fly the fuck apart after just one or MAYBE two shots? How will he ensure and regulate consistent amperage? How will he mount it? How will he transport it?

And the end all be all, WHY ARE YOU LETTING HIM METAGAME.A HIGHLY ADVANCED THEORETICAL WEAPON HE WOULD HAVE NO CONCEPT OF WITH HIS OWN SCIENCE AND NATURAL PHILOSOPHY!?

>Go the full length. Make it a legit, outright railgun. Massive power, capable of piercing practically anything, and an insane range. It can legitimately one-shot anything. (peak of modern technology vs fantasy, yeah tech wins).
>But then include everything a railgun entails. And that is a mechanism which requires constant expensive repairs. Modern railguns can fire about two to three shots before needing full repair, if not outright replacement.
>If he's smart, he'll realize there's no way this can viably be used constantly. Not with how rare materials are. So his empire or whatever now has a trump card. One final weapon, with extremely limited use that finishes off anything that was so overwhelming as to force its use.
>Remember kids, modern technology can always be freely put in fantasy. Just remember to put in the sheer cost of it which fantasy can not compensate for, whereas modern day can.

This is approximately what I would do.

As a DM, I hate doing the "yes but no" thing where you do something but then withdraw it because you didn't consider the implications.

I don't know about "massive power" because he's charging it off eels here, but I'd let him have a real rail gun maybe about as powerful as a .50 rifle (or whatever is appropriate to your game.

He can either have it built into a massive metal scaffold that must be moved by cart, or a much lighter version that can be maneuvered by hand but is liable to tear itself apart after each use.

>but the whole purpose of the electricity is to "turn on" the magnetic effect on demand. If they're constantly magnetic and in a single direction, how do you use that in a railgun?

You can do a railgun with perma-magnets by moving the variable electric field to the projectile.

Nobody does this IRL because it is ridiculous when electromagnets are so useful for the rails, but it's not beyond the realm of the theoretically possible.

>You realize that energy is conserved, right? To get a "mini nuke" you need a mini nuke worth of energy. Shooting a tiny rock very, very, very fast is actually not some incredible super weapon.

Like I said, he's gonna need a looooot more energy than just a few eels. In fact, the railgun should only do half as much damage as the electrical shocks the eels output. Or whatever power source he uses.

That's already being nice, as modern railguns only get about 30% efficiency instead of the 50% supposed above.

Thats where i got the idea, but air resistance would mean a terminal velocity, hence the vacuum.

There are a few limitations though. You let it build up too fast, your projectile disinegrates as soon as it hits the atmosphere, and would generate an ungodly amount of muzzle blast, as in, igniting the air itself, and being inside a solid metal tube, you can see how fast its going, so some hilarious practice is involved.

>alright, junior artificers! Yesterday we determined that a solid round iron ball with 1 minute of buildup will shrapnelize shortly after leaving the barrel. Today, we have the great luck of using an adamantine sphere weighing roughly 5 pounds. Knowing the resilience of the material, i took the liberty of starting the buildup last night!

>now, extra credit to whoever gan figure the current velocity of our current projectile if it has been under 1g of movement with no friction for 12 hours now?

Go!

Unless the magnets are powerful enough to propel a rock that fast, it won't work. What, you think you think you can make a railgun with some kitchen magnets and an electric toothbrush?

>Peasant railgun
>Simultaneously ignoring physics for game rules and game rules for physics
No.

There was a gun from a magical scifi article for dragon magazine over a decade ago that worked on this principle. You loaded a "bullet" into a chamber, fired it off, and it would travel through a portal into an unused section of space to be accelerated into a ridiculous speed, and then come out another one pointed where the gun aimed. The result was a powerful handgun that would kill whoever or whatever it was aimed at.

They were of course outlawed and made utterly illegal to own.

And I forgot to mention the time magic that sent the projectile back in time a few minutes or so to get proper acceleration going before getting blasted out the end of the gun.

Thanks very much. Building a campaign setting that the players are all invested in and aware of the basic goings on is why I want to try running a builder

Ah, you might not want to use mine then. It's designed to be played on the internet over a college semester. You could probably modify it, but it might be a bit more expansive than what you're looking for.

>somewhere between ridiculous and overpowered
Do you have creatures/wizards that can hurl fireballs, lighting bolts, etc? If yes then it is fine.

>By placing the rocks in a line and charging them in sequence he proposes to fire a high velocity projectile.
Tell him it doesn't work.

Best rail gun ever, too bad her best friend was a total cunt

>WHY ARE YOU LETTING HIM METAGAME.A HIGHLY ADVANCED THEORETICAL WEAPON HE WOULD HAVE NO CONCEPT OF WITH HIS OWN SCIENCE AND NATURAL PHILOSOPHY!?

This man asks an important question.