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Reverse Engineering For Fun and Profit (Planetary Annihilation/Multicross SI)

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NHO said:
Obvioulsy, Impaler is gauss-boosted weapon instead of pure gauss cannon, to improve efficiency.
At lease, Impaler that used that case.
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That actually has a good bit of truth to it. If I remember correctly, the last big limitation on deploying railguns by the USN was rail life. Specifically, they can get around 400 shots out of a set of rails before needing to be replaced.* One of the ways that the engineers found could extend it was to inject inert gas into the breech of the gun, propelling the projectile into the barrel, which would decrease the amount of wear on the early portions on the barrel. I'm not sure how smokeless powder would effect that though. Hmm, food for thought.

*As a side note, for most people, 400 shots would be more than enough, but the USN wants 1000. Although, this number was from a Congressional budget hearing in 2014, so it's probably higher now.
Lost Star said:
If I remember right, there's a serious issues with recoil and other problems for our current railguns.
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Most of the technical issues regarding railguns have actually been solved at this point. The biggest things preventing deployment is barrel life, as mentioned already, and having a sufficient amount of electrical power available to fire the rail gun at a rate of ten rounds per minute. The second one is a particularly thorny problem that ensures that the Zumwalts are really the only ship that can feasibly mount the things and fire them at the maximum rate. We only have three of them. Land-based artillery installations would work, but would be horrifically vulnerably to counter-battery fire. Alas, the age of the missile has not yet ended.
 
NHO said:
Almost ninjaed.

Rail weapon - and gauss weapon, too, AFAIK, works more efficiently if thing to accelerate already has some initial velocity. So using initial propellant to to start up and then boost with rails/coils is a valid design choice, combining best of both worlds and efficiency in return for more complex gun.
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As I understand things that isn't quite how stuff works IRL. The problem is that the length of the rail of a weapon is fairly limited by practical problems. And there is also a limit to how much force a magnetic weapon can impart on a projectile. The energy the system can give to a round is therefore based on how long the round is actually in the barrel. If the round is already moving at a significant speed then it'll be in the barrel for a much shorter time and therefore the system can't provide as much energy to it.

That is probably also the reason why the system is mainly focused on battleship guns right now. A battleship gun round is heavy, which means it carries more energy at a given speed than a small bullet does. Therefore it'll be in the barrel longer than it would be if it where lighter, and therefore the gun is more efficient comparatively. Handguns are pretty much the worst case scenario for electromagnetic weaponry.


That said the reason I brought this up is because this is all very much up in the air right now. If you want to handwave that the Terrans found some way to do make it so that accelerating a speeding bullet is more efficient you can do so comparatively easily (for now, no promises for a decade or two from now). And if you do handwave things that way some of the more narratively important parts line up, what you see and what is written in canon don't conflict.
 
vyor said:
Wrong, the round never touches the barrel. There is no wear there, what wears down is the capacitors.
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<Gibbs> I dunno, man, I have to swap 'em out every so often. Didja know Zerglin' blood is mighty unhighjennic an' corrosive? And don't get me started on these 'ere space zombies! They ain't as bad for wear an' tear, tho'. Skulls ain't as tough as Zerg Carapace.
<Isaac> *eyetwitches*
<Gibbs> ...You okay there, buddy?
<Isaac> *TWITCH* Why?! Why does a machine gun have a bayonet?!
<Gibbs> Fer stabbin'. And roastin' marshmellers. Mostly the stabbin', tho'.
 
TikiTau said:
<Gibbs> I dunno, man, I have to swap 'em out every so often. Didja know Zerglin' blood is mighty unhighjennic an' corrosive? And don't get me started on these 'ere space zombies! They ain't as bad for wear an' tear, tho'. Skulls ain't as tough as Zerg Carapace.
<Isaac> *eyetwitches*
<Gibbs> ...You okay there, buddy?
<Isaac> *TWITCH* Why?! Why does a machine gun have a bayonet?!
<Gibbs> Fer stabbin'. And roastin' marshmellers. Mostly the stabbin', tho'.
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Why didn't you put baby powder on it? Would keep the acid from eating through the metal.
 
TikiTau said:
<Gibbs> I dunno, man, I have to swap 'em out every so often. Didja know Zerglin' blood is mighty unhighjennic an' corrosive? And don't get me started on these 'ere space zombies! They ain't as bad for wear an' tear, tho'. Skulls ain't as tough as Zerg Carapace.
<Isaac> *eyetwitches*
<Gibbs> ...You okay there, buddy?
<Isaac> *TWITCH* Why?! Why does a machine gun have a bayonet?!
<Gibbs> Fer stabbin'. And roastin' marshmellers. Mostly the stabbin', tho'.
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When you're used to Zerg charges you'll start to wonder, Why does your gun LACK a bayonet?
 
vyor said:
*face palms*

They don't use a rail gun, it's a coil gun. There is no rail wear.
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vyor said:
Wrong, the round never touches the barrel. There is no wear there, what wears down is the capacitors.
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What. The scientist in me says, "Theoretically possible." The engineer though is saying, "They want to do what?!" I mean, sure. You could have the slug be suspended in an electromagnetic field and then be accelerated that way. But then it's a trade off. Sure, you may not have to deal the barrel wearing out, but now everything else is twice as big to deal with the efficiency loss. And when weight and size (and thus cost) is a critical thing, which it is for just about everything, it's a bad trade off. Practicality tends towards stuff being good enough rather than perfect.
 
Decim said:
What. The scientist in me says, "Theoretically possible." The engineer though is saying, "They want to do what?!" I mean, sure. You could have the slug be suspended in an electromagnetic field and then be accelerated that way. But then it's a trade off. Sure, you may not have to deal the barrel wearing out, but now everything else is twice as big to deal with the efficiency loss. And when weight and size (and thus cost) is a critical thing, which it is for just about everything, it's a bad trade off. Practicality tends towards stuff being good enough rather than perfect.
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That's how coil guns work. The round floats in the middle and is pulled along. It's actually more efficient since you don't need to worry about the drag from the barrels themselves.
 
Decim said:
What. The scientist in me says, "Theoretically possible." The engineer though is saying, "They want to do what?!" I mean, sure. You could have the slug be suspended in an electromagnetic field and then be accelerated that way. But then it's a trade off. Sure, you may not have to deal the barrel wearing out, but now everything else is twice as big to deal with the efficiency loss. And when weight and size (and thus cost) is a critical thing, which it is for just about everything, it's a bad trade off. Practicality tends towards stuff being good enough rather than perfect.
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Well; do remember that the gun is supposed to be wielded by people in full huge Powerarmour. The guns being bigger is a good thing in this case.
 
From what I've read and played, there are basically four types of weapons in sci-fi settings.

First, Direct Energy Weapons. Basically, every 'laser gun' ever. Lasguns, Starcraft Battlecruiser main armaments, etc.

Second, Kinetic Energy Weapons. If it fires a 'bullet', its this. Pistols, Autoguns, snipers, Impaler Gauss Rifles, etc.

Third, Energy Delivery Weapons. Missiles, grenades, torpedoes, Bolters, Plasma weapons (something is containing the plasma during delivery), etc.

And Fourth, Exotic Weapons. The really freaky shit that just doesn't quite fit into the above. Please note, even miniature singularity weapons can fit into the third category, if you squint a little bit. This is for quantum fuckery, gravitic distortions (as opposed to black hole generation), and other exotic effects.

As a weapon, especially a ranged weapon, is basically a means of delivering energy from point 'a' to point 'b', the primary difference in the above is how that is accomplished.
 
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Jokarun said:
When you're used to Zerg charges you'll start to wonder, Why does your gun LACK a bayonet?
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The standard Impaler does have a bayonet.
vyor said:
That's how coil guns work. The round floats in the middle and is pulled along. It's actually more efficient since you don't need to worry about the drag from the barrels themselves.
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No, not really. If you want it to constantly float, then you'd need to have a constant upwards magnetic force the entire way. That's
a) hard to do
and b) at that point, you basically have a railgun pointing up.
 
FullNothingness said:
The energy the system can give to a round is therefore based on how long the round is actually in the barrel
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Ah, nope. Energy imparted to something is force · distance, and is independent of how long the object experiences the force.
What you're thinking of is impulse, force * time. That's the change in momentum. So, the faster something goes through something, the less its velocity changes. But you still wind up with more energy than you started with.
And also, there are railgun prototypes that shove the slug into the rails via a light gas gun.
 
Wobulator said:
No, not really. If you want it to constantly float, then you'd need to have a constant upwards magnetic force the entire way. That's
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exactly how a coil gun works.

Wobulator said:
and b) at that point, you basically have a railgun pointing up.
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No.

Just... no. A railgun works like this:
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The railgun round completes the circuit between 2 rails, this completion activates magnets, pulling the slug up and out, this is why it wears the rails down.

A coilgun on the other hand does not do this. A coil gun uses just that, a coil. Wires wrap around a tube, as electricity moves through it the magnetic field moves with it. The slug never touches the barrel as a result. This is why what you are saying is dumb and makes no sense.

That concludes our 4th grade science lesson.
 
vyor said:
exactly how a coil gun works.
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No? A coil gun is a series of coils, each of which provides a pulse. There's no constant force at all.
Unless you're gonna make a single giant coil(which is inefficient), you're going to have the projectile "wobbling" up and down as it enters and exits coils. You could stick the entire thing in a coil pointed up, but why would you do that?
 
Wobulator said:
No? A coil gun is a series of coils, each of which provides a pulse. There's no constant force at all.
Unless you're gonna make a single giant coil(which is inefficient), you're going to have the projectile "wobbling" up and down as it enters and exits coils. You could stick the entire thing in a coil pointed up, but why would you do that?
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wobbles?
 
Wobulator said:
No? A coil gun is a series of coils, each of which provides a pulse. There's no constant force at all.
Unless you're gonna make a single giant coil(which is inefficient), you're going to have the projectile "wobbling" up and down as it enters and exits coils. You could stick the entire thing in a coil pointed up, but why would you do that?
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This depends entirely on the relative strength of the magnetic fields of the coils compared to gravity, the distance between them and the speed of the projectile. And if these coil guns have an acceleration equal to or better than chemical explosive based weapons (they'd better, explosives based propulsion is much less complicated) the level of projectile drop in the barrel is going to be negligible.
 
Gah. I may have made an error, previously.
Working coil, as far as I can remember, wants to place magnetic object in geometric center. So you turn coil on when spike enters it and turn it off when spike passes halfway.
This includes counteracting gravity. So, you need a barrel or your shot will fly randomly away, due to amplification of random wobbles.

Because force isn't parallel to axis of the coil, it directed from projectile to the center of the coil.
 
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My headcanon is that the shells are from the power generator. I remember reading (on Wikipedia, I can't find it again) that we have built generators that run on (and are broke by) an explosion to make lots of power for a few milliseconds.
 
vyor said:
wobbles?
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Hazard said:
This depends entirely on the relative strength of the magnetic fields of the coils compared to gravity, the distance between them and the speed of the projectile. And if these coil guns have an acceleration equal to or better than chemical explosive based weapons (they'd better, explosives based propulsion is much less complicated) the level of projectile drop in the barrel is going to be negligible.
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Because force is relative to distance squared, it's decidedly not constant, especially given that you keep on turning coils off behind you. As the projectile nears the coil, the force on it increases, both forwards and upwards.

EDIT: Actually, nevermind. You're right, the wobble is negligable.
 
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