Tau vs Galactic Empire question

[hunter5]

Okay so from the Star Wars Rebels show we have seen that the Mass driver cannon on an AT-TE cant hurt and AT-AT. So how does this translate to a Tau Hammerhead rail cannon ability to hurt an AT-AT?

[Simon_Jester]

[Deep breath]

It's gonna be hard to quantify the performance of either weapon.

Given that the Tau heavy antitank railguns are built to roughly the same scale as the dorsal gun on an AT-TE, and given that I know of no evidence for the Tau having more sophisticated technology than the Empire in any particular respect... I would assume that Tau antitank railguns would not be particularly effective at doing what an AT-TE dorsal gun can't.

[Eternal_Freedom]

Indeed. I would suspect that since an AT-AT is roughly similar in size to Imperial Titans you would need the next size up railgun to reliably hurt it with one or two hits.

[Elheru Aran]

Indeed. I would suspect that since an AT-AT is roughly similar in size to Imperial Titans you would need the next size up railgun to reliably hurt it with one or two hits.

So something like this, perhaps?

[Eternal_Freedom]

Don't get me started on those fucking giant Battlesuits. Real pain in the ass to kill the fuckers.

[Venator]

Okay so from the Star Wars Rebels show we have seen that the Mass driver cannon on an AT-TE cant hurt and AT-AT. So how does this translate to a Tau Hammerhead rail cannon ability to hurt an AT-AT?

I don't know the full lore, but given that the AT-TE in SWR had a fabric tonneau cover and a balcony on it, it's possible that it was either using substandard ammunition or simply wasn't running at peak power.

With that said, the kinetic effects of the AT-TE guns aren't terribly striking - see the rock-face impact when fired at Obi-Wan in RoTS - compared to descriptions of Tau railguns (such as vehicular overpenetration of Imperial tanks, where the only signs of damage are neat entry and exit holes and the complete liquification of the crew due to pressure differential).

Still, GE armour technology is similarly impressive to the IoM's, and the AT-AT's armour is a standout even by those standards - either insanely heavily armoured (or armoured-and-shielded depending on who you ask), probably to counteract the fact that everything in the same post code could draw line of sight to engage one.

[NecronLord]

Okay so from the Star Wars Rebels show we have seen that the Mass driver cannon on an AT-TE cant hurt and AT-AT. So how does this translate to a Tau Hammerhead rail cannon ability to hurt an AT-AT?

No one has ever to my knowledge, produced calcs for both weapons, though I think some data on the AT-TE was present in the ICS. So, who knows? They function the same way, but that doesn't mean they're equally powerful.

[Batman]

The E2 ICS states that the massdriver has 'variable yield'

[Crazedwraith]

The E2 ICS states that the massdriver has 'variable yield'

But also that the six laser cannons have 5x10e9 Joules max yield per shot. The main gun should be in the same ballpark. (Unless it fires really specialised ammo)

[Simon_Jester]

It would honestly not surprise me to learn that the AT-AT can shrug off gunfire/bolts/whatever with yield comparable to one ton of TNT equivalency (4.2*10^9 joules). Or for that matter ten tons.

The E2 ICS states that the massdriver has 'variable yield'

Against a target as large and hardened as an AT-AT...

Only a complete imbecile would fire it set to anything but the maximum yield.

[Elheru Aran]

The E2 ICS states that the massdriver has 'variable yield'

Against a target as large and hardened as an AT-AT...

Only a complete imbecile would fire it set to anything but the maximum yield.

As noted (I believe I've seen a trailer for the episode in question, so I recall the general configuration of this AT-TE), this was a walker that had been converted after the fact into some manner of.... Star Wars style RV. (Shades of Spaceballs, anybody?) So I find it not unlikely that either they were low on ammunition, or didn't have the highest yield ammunition available because it had all been fired off already. This is particularly likely if the AT-TE was scavenged from a battlefield or some such situation.

[Balrog]

I'm not sure we know enough to make a call either way. I mean for one thing what do we know for sure about the Tau railgun? The smaller railguns carried by Broadside suits are said to launch projectiles between Mach 7 and Mach 10, so I think we can assume the railgun is capable of firing at those velocities as well, but what about the projectile itself, weight/shape/et cetera? I also recall reading somewhere that physical impacts which take place at hypervelocity don't act the same as at slower velocities, that there is actually even less penetration or somesuch, but would have to double check on that.

[Gunhead]

I'm not sure we know enough to make a call either way. I mean for one thing what do we know for sure about the Tau railgun? The smaller railguns carried by Broadside suits are said to launch projectiles between Mach 7 and Mach 10, so I think we can assume the railgun is capable of firing at those velocities as well, but what about the projectile itself, weight/shape/et cetera? I also recall reading somewhere that physical impacts which take place at hypervelocity don't act the same as at slower velocities, that there is actually even less penetration or somesuch, but would have to double check on that.

You're probably thinking about phase transition where solid materials start to behave like liquids when under extreme pressure. At high velocities, angle of impact is mostly relevant to thickness since at these speeds, deflection doesn't really happen anymore. This starts to take place around 1500-1600m/s speeds. At least on paper, the increased velocity translates directly to increased penetration but in reality it's lot more complex. The penetrator has to be able to withstand the impact while retaining it's shape to force the armor material to give way as it passes through it. If you can break the penetrator apart, the velocity can in fact work against it because parts of it are moving at different speeds. This affects any kind of rod shaped penetrators, because the mechanism is really about the ratio of thickness vs. length.

-Gunhead

[Simon_Jester]

I'm not sure we know enough to make a call either way. I mean for one thing what do we know for sure about the Tau railgun? The smaller railguns carried by Broadside suits are said to launch projectiles between Mach 7 and Mach 10, so I think we can assume the railgun is capable of firing at those velocities as well, but what about the projectile itself, weight/shape/et cetera?...

It's a tabletop wargame, no way are we getting useful information on the details of how a hypersonic penetrator is designed.

It's safe to assume that the penetrators are made from some kind of exotic, very strong material, but that's just because it's science fiction in a soft SF setting. It's also safe to assume they have roughly the same mass and bulk as ordinary artillery rounds, because they're built to the same physical scale.

We're better off trying to observe the effects of the weapons on their targets, not trying to find the details of the weapon's design and function as written by Black Library writers who would get the details wrong if they even tried to include them.

I also recall reading somewhere that physical impacts which take place at hypervelocity don't act the same as at slower velocities, that there is actually even less penetration or somesuch, but would have to double check on that.

As noted, hypervelocity impacts basically care a lot more about a few key traits- the strength of the impactor, the angle of impact as it affects the thickness of armor material to pass through, and the presence or absence of active countermeasures that damage or break up the impactor before it hits the main armor belt. If the first of those things is lacking, or the third is in play, you usually just get a crater made in the armor by the impactor.

[Elheru Aran]

We're better off trying to observe the effects of the weapons on their targets, not trying to find the details of the weapon's design and function as written by Black Library writers who would get the details wrong if they even tried to include them.

I want to say Connor Macleod did some work on that when he analyzed that Ciaphas Cain novel with Tau. There's a scene where a railgun round hits an omnibus (IIRC) and shreds it. I have no idea where the hell to find that thread though...

Never mind:

http://bbs.stardestroyer.net/viewtopic. ... 1#p3774730 (post in question)

No calcs, though.