Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Esna Pitoojee]

I knew I had seen a bit of fiction that discussed this, and now I present an excerpt from "Recursion", a short (chronicle-length) piece done by CCP Headfirst for Kirith Kodachi's Inner Sanctum of the Ninveah:

The cylinder had barely cleared of its previous occupant and was still clouded with scalding hot residual smoke when the breech shot back open. A belt of reinforced, flexible carbon fibers pulled from left to right, yanking the hollow shell out of the way so that the next round could slam into place, where it was immediately secured by a locking collar at the front and back of the chamber.

A fraction of a heartbeat after it had settled in, though, the back of the cylinder segmented near its center, sending a solid piston of polished steel slamming into the back of the round. The force of the impact, along with the crackling spark it caused upon touching the bullet, ignited the explosive gel contained inside. As each molecule of the heavy composite paste overheated, the atoms within shed their higher level electrons, which in turn heated up their neighboring particles, and so on in a chain reaction.

As the available space in the shell rapidly filled with a blistering inferno of hot gas, ripples of tension reverberated down the outer casing of the bullet, causing it to expand the last few millimeters between it and the cylinder’s wall. When there was no more room, the expansion could only press forward, where the only thing standing between it and the welcoming vacuum of space was a titanium sabot projectile.

Note that the ship in question is a Rupture using autocannon.

Important facts:
- Medium-caliber autocannon, at least, use a shell-projectile combo that is already in a fixed state when it enters the barrel.
- Shells are in a belt linked by carbon fiber. This is extremely unusual; to my knowledge, no mass-produced weapon in real-life has used a belt which actually entered the chamber with the shell, instead usually extracting each shell from the belt and then separately ejecting the spent shell and belt or belt remains. Carbon fiber is a reasonably good material to work with should you want to use such a mechanism, though - even in the environment of an autocannon of that size, it is unlikely to melt, chemically react, expand from heat, permanently deform or shatter under shock.
- The propellant in a cruiser-size autocannon is a gel- or paste-like substance, ignited by both mechanical shock and electric ignition. There is no mention of a primer material.
- The casing expands "a few millimeters" during firing before it is pressed against the breech walls. Given that the casing is secured in place by a pair of collars during firing, it seems likely that this refers to the rear of casing expanding towards the back of the breech.

A thanks to Synthetic Cultist for locating this bit of fiction for me.

[Elmund Egivand]

This more or less confirms that autocannon shells, at least medium-sized, are cased. However, there's a few things that strikes me as odd. First, using carbon-fibers to yank out the shell? This seems oddly inefficient. You would think that they would just stick an ejection port on the side or something to reduce delay time and increase firing rate. Also, this piece of fiction sort of struck me as outdated and written before the turrets were remodeled. I would think that the current autocannons are magazine or belt fed, to improve rate of fire as well as explaining why it would take 10 seconds to reload the autocannon (10 seconds for robotic arms and other machinery to load and lock mags/belt in place).

[Erys Charantes]

This more or less confirms that autocannon shells, at least medium-sized, are cased. However, there's a few things that strikes me as odd. First, using carbon-fibers to yank out the shell? This seems oddly inefficient. You would think that they would just stick an ejection port on the side or something to reduce delay time and increase firing rate. Also, this piece of fiction sort of struck me as outdated and written before the turrets were remodeled. I would think that the current autocannons are magazine or belt fed, to improve rate of fire as well as explaining why it would take 10 seconds to reload the autocannon (10 seconds for robotic arms and other machinery to load and lock mags/belt in place).

I'd have to agree. Remembering how modern naval guns work, and looking at game mechanics, I would say that it's pretty clear that every ship mounted weapon (lasers being the exception, for obvious reasons) uses a ready magazine setup, holding an on-mount payload of munitions that is automatically replenished from the ships main magazines.  For an artillery cannon, this likely means single rounds feed into a rotating carousel that can be quickly emptied and refilled.  I'm with Elmund on the interchangeable linkless belts being a better option...  Maybe they changed it with the remodel, lore wise? Given that autocannons fire very rapid bursts of very heavy shells, the described mechanism would be under incredible strain.  Still, lore is lore. 

[Lyn Farel]

I'm holding to the opinion that it's an overthought answer to a game simplification, Saede.  The utter lack of any description as to how it might work in prime lore bespeaks such...  It works because of reasons.  The problem with "expando" rounds is that, regardless of how much you expand a smaller shell, its still going to have the warhead of a smaller shell. I could buy them being reprocessed into the appropriate load, but not resized on the fly.  You'd have to resize everything.   More or less propellant, the warhead, triggers for said warhead...  Otherwise, you're just firing underpowered rounds, our having to neck down larger ones.  Sabots would allow you to fire a smaller round from a larger tube, but it would still be the smaller round.

As for hybrid charges, they're not the same.  The plasma round that Matari guns fire use a similar warhead, but use a propellant charge to fire it. Hybrid rounds have no propellant whatsoever, no case either. They're launched by magnetic acceleration. A conventional cannon could not fire them at all, even if the round was sized for the bore.

I'm of the school of thought that if ingame mechanisms do not fit to PF, or just do not fit to coherent explanations and credibility, thus breaking the suspension of disbelief, then the lore trumps ingame, period. PF is the universe, ingame is just a simplification of it to offer a certain code and standard of fun and gameplay. That way, it is impossible for me as well to grab ammo in a wreck that was fired by 650mm canons and fit them into my 720mm canons, unless there is PF handwavium involved, which mean, some tech allowing them to be universal. Otherwise it's putting the cart before the horse.

Also, firing underpowered rounds does not mean unefficient. Most of the power of a projectile gun comes from the gun. Though I would agree that it would be more efficient to actually use the whole caliber of the biggest calibers...

Also, the plasma warhead has nothing similar to the hybrid charges, since the latter are made of a single metal component (iron, lead, uranium, etc) fired at high speeds with electric/magnetic acceleration in the case of railguns, and transformed into balls of pure plasma by blasters (not the gimped version of the minmatar plasma shell). What I am still struggling with is why is there also antimatter in the case of hybrids. That's not a metallic component, and should require a whole different tech to fire, and also, has probably to be contained into a shell, unlike other hybrid charges...

[Elmund Egivand]

I'm holding to the opinion that it's an overthought answer to a game simplification, Saede.  The utter lack of any description as to how it might work in prime lore bespeaks such...  It works because of reasons.  The problem with "expando" rounds is that, regardless of how much you expand a smaller shell, its still going to have the warhead of a smaller shell. I could buy them being reprocessed into the appropriate load, but not resized on the fly.  You'd have to resize everything.   More or less propellant, the warhead, triggers for said warhead...  Otherwise, you're just firing underpowered rounds, our having to neck down larger ones.  Sabots would allow you to fire a smaller round from a larger tube, but it would still be the smaller round.

As for hybrid charges, they're not the same.  The plasma round that Matari guns fire use a similar warhead, but use a propellant charge to fire it. Hybrid rounds have no propellant whatsoever, no case either. They're launched by magnetic acceleration. A conventional cannon could not fire them at all, even if the round was sized for the bore.

I'm of the school of thought that if ingame mechanisms do not fit to PF, or just do not fit to coherent explanations and credibility, thus breaking the suspension of disbelief, then the lore trumps ingame, period. PF is the universe, ingame is just a simplification of it to offer a certain code and standard of fun and gameplay. That way, it is impossible for me as well to grab ammo in a wreck that was fired by 650mm canons and fit them into my 720mm canons, unless there is PF handwavium involved, which mean, some tech allowing them to be universal. Otherwise it's putting the cart before the horse.

Also, firing underpowered rounds does not mean unefficient. Most of the power of a projectile gun comes from the gun. Though I would agree that it would be more efficient to actually use the whole caliber of the biggest calibers...

Also, the plasma warhead has nothing similar to the hybrid charges, since the latter are made of a single metal component (iron, lead, uranium, etc) fired at high speeds with electric/magnetic acceleration in the case of railguns, and transformed into balls of pure plasma by blasters (not the gimped version of the minmatar plasma shell). What I am still struggling with is why is there also antimatter in the case of hybrids. That's not a metallic component, and should require a whole different tech to fire, and also, has probably to be contained into a shell, unlike other hybrid charges...

The power of the autocannon more accurately comes from the shell caliber. Force is mass times acceleration after all. The mass comes from the shell. The acceleration comes from the propellant. If there isn't enough propellant, or the shell isn't large and heavy enough, you fire an underpowered shell that can't do as much damage as it should. It IS inefficient. So yes, you can resize the shell, but you must also adjust the mass of propellant and the mass of the shell itself to compensate. All the gun does is aim at the thing you want dead, ignite the propellant and send the shell into his face.

And I assume that the anti-matter was contained in the canister by a magnetic field, and was then launched into people's face.

[Lyn Farel]

A good chunk of the speed always comes from the length of the nozzle. And another part of what you say. But eventually in the case of projectiles it mostly depends if the main application is meant to penetrate (like AP) or to cause damage (like HE).

If the former, then the chemical compound is useless and you end up with a pure dense metal shell made to pierce through armour. Weirdly enough in eve, explosive is the most effective way to pierce through armour of spaceships, where in real life it is mostly useless unless used as HEAT (which is totally obsolete these days, completely beaten by reactive armour and new compounds). Kinetic should be the most effective, but whatever.

And if the latter, the chemical compound is the main factor, the one that creates the explosion/effect causing widespread damage (as opposed to localized piercing). In that case the length of the nozzle is insignificant and will just add kinetic power that we don't need (to cause the maximum damage against soft targets, you want to avoid too much speed, see how poor is a tank destroyer IRL against soft targets when using HE).

That said I would tend to see HE style effects needed to overcome a shield and saturate it, and AP effects to pierce through armour. Which means that you need an all purposes canon capable of dealing both. I would expect to see EMP and plasma munitions mostly made for the former and titanium sabot for the latter. That's also maybe why we don't have too much high damage short range explosive ammo for projectile ammo (the only T1 one is nuclear iirc...), except T2 specialized ones like barrage and hail. Maybe those ones make a special use of explosive property to pierce through/obliterate armour..

As for railguns and blasters, that's my issue, those use pure metal rounds since a railgun bases everything on kinetic speed, and the blaster just transforms it into a ball of plasma. I can understand that antimatter to work for blasters, but how does that fit with the properties of a railgun ?

[Morwen Lagann]

Fusion is the close-range explosive projectile ammo. Nuclear is actually one of the long-range ammo types along with Proton and Carbonized Lead.

[Lyn Farel]

Ah shit, I forgot fusion... I was pretty sure something was missing.

[Morwen Lagann]

To be fair, I wasn't sure if you meant lore-wise or actual damage types, but figured I should point it out just in case.

Been using projectiles way too much lately for my own good...

[Elmund Egivand]

Yes, nozzle speed is also important. Thanks for reminding. But you cannot deny that under powered projectiles are far from irrelevant.

And join us, Autocannoneers! Join us in Dakka-ing the stars!

[Katrina Oniseki]

Yes, nozzle speed is also important.

You mean muzzle speed?

[Elmund Egivand]

Yes, nozzle speed is also important.

You mean muzzle speed?

Put me in a dress and call me Patsy. You are right.

[Katrina Oniseki]

Yes, nozzle speed is also important.

You mean muzzle speed?

Put me in a dress and call me Patsy. You are right.

Nozzle Speed.

[Elmund Egivand]

Yes, nozzle speed is also important.

You mean muzzle speed?

Put me in a dress and call me Patsy. You are right.

Nozzle Speed.

The future of Minmatar combat.

[Ayallah]

Explosive against armor makes perfect sense to me.  Works like an AT rocket scaled down into some high speed super-projectile.  Like that new matt damon movie #winmatar.

As for the shells, it would be completely lame to have to buy 30 kinds of ammo.  This is a simplification obviously and people should consider getting over it.  Expanding rounds or larger and larger sabots are silly and make no sense.

As for how they work, causeless ammunition in the large kind of guns that EvE uses (smallest is still the size of a howitzer) doesn't make sense, they were made to save weight and be less volatile.  Modern or super-modern technology has various gels and forms of propellent that are nonvolatile.  Hell, use c4.

I always imagined it as an automated process involving cased ammunition.  There isn't a real reason why the story above does not work, it works like most machine guns it is just picture it without the casing.  It would work just as well though.  And disintegrating belts are a more modern invention and doesn't really have a place on a starship.  Hell, the linked powder casing could even be machined out of a space material that is flexible.  Breech closes around it and it fires then it extracts and flattens so it can be spooled into a drum to not take up as much space. 

I mean in the end, it is a giant machine gun.  Machine guns are not difficult.