Imperial armour: Siege of Vraks analysis

[Black Admiral]

The Idiot Korps of Krieg's certainly are.

[Gunhead]

I forgot this. If both sides are using the Leman Russ aka "PoS". It's really hampered on the defense. It needs to expose the hull to bring it's full firepower into the fight negating the cover advantage or forcing it to rely on it's main gun to engage enemies reducing it's ability to mow down infantry greatly. Pintle mounted weapons might alleviate the problem somewhat, but this exposes a crewman possibly the commander and hampers his ability to command the tank.

-Gunhead

[KhorneFlakes]

The fact that their name is the Death Korps of War is the thing I hate the most. Blow up the fucker's sun. They really don't deserve to exist. Far too much dark that it's just fucking annoying, rather than actually achieving anything.

[Sea Skimmer]

Well rather than guessing what sort of performance and size of vehicle you're talking about, could you clarify exactly what you're thinking of? Are we really talking something like a floating Bolo or Titan? How high off the ground is it operating? How fast is it moving?

Not as big as a Bolo or Titan no, though that would be great if you could build it. Something with no more size or firepower then a main battle tank that could fly would be revoltuonary enough, but I’m thinking of a craft in the size and armament range of the Finnish Ilmarinen class coastal defense ships, able to fly 100-200 feet high, sufficient to negate all conventional counter mobility tactics, as well as firing over trees and buildings. Speed would not need to be any better then that of ground vehicles. Bingo, you have armored air cavalry.

Basically the idea is merge the mobility and terrain masking abilities of a helicopter gunship with the firepower and armor of tanks and artillery, and the integrated defenses of a warship. Even if it was not as good as any of those categories in isolation, the combination of effects would be near unstoppable by anything but air power. What’s more, effectiveness would actually increase the worse the terrain gets as its mobility advantage counts for more and terrain masking is easier. 40K seems like it has the technology to do this.

What about vehicles? The implication I got from the book (and as I've noted) is that the Vraks storehouse had a literal shit-ton of vehicles, quite probably more than the Krieg themselves had (either that or the Krieg just like sending their troops in on foot by Imperial armour fiat.) Another possibility is that Vraks may have stored alot of remote control/automated gunnery emplacements - stuff like Tarantulas or servitor controlled guns and stuff that can contribute heavy weapons firepower in static positions at least.

Artillery fire should really just be destroying all of that, and cratering the landscape so much armored vehicles can’t even counter attack over it. In fact to certain extents it would make actual sense for the Krieg not to be vehicle heavy, if they were very centered in artillery that can blast craters tens of feet deep. Tanks would all get stuck really quickly. Also the attacker has a serious advantage in a circular situation like this, in that his attacks and fires are converging into a narrower area, while the attackers efforts are spread over a divergent path.

Yeah, I should have allowed for the angle of fire. It also may not be so much backwards movement as the front of the tank lifting off the ground. Which isn't good either. I'm pretty sure that's a good sign the gun on your vehicle is pushing (or exceeding) the safe limits of gun recoil.

Well, that’s why in real life certain self propelled artillery pieces have recoil spades that physically dig into the ground, and many towed pieces also can have spades dug in by hand. Its not uncommon for artillery designs to be able to shift themselves a little bit, but you can counter this if you have any sense.

As late as 1945 the British still had towed artillery which used RAMPS to absorb recoil due to them having painfully obsolete conversions of WW1 economy designs still in service.

It's less the battlefield salvage than the 'Meat Droid' Krieg doctrine andhow they're used in this book, plus the Munitorum 'doctrine' that technology and equipment is inherently more valuable than men. They really do believe that a lasgun is more valuable than the soldier wielding it, and soldiers are told they should save the gun before saving the trooper. They care about their own purview alone and everything else can go to hell (training may or may not matter here - since they can either just poach a planet's own defence forces for trained troops, or may just decide to use conscripts, training isn't always a big cost for them I'd say.)

Too bad the battle wasn’t written as an attempt at a quick lighting campaign. Stuff like this might make sense if the fortress had to fall in a month, and no seriously wounded man would have a chance of recovering in time to be useful. Also would help if they had local conscripts to force into the battle at gunpoint or via brainwashing rays. With 12 years in the plan and a 1,000 mile railroad to operate… wounded people are kind of seriously useful even if missing limbs.

[Zinegata]

I forgot this. If both sides are using the Leman Russ aka "PoS". It's really hampered on the defense. It needs to expose the hull to bring it's full firepower into the fight negating the cover advantage or forcing it to rely on it's main gun to engage enemies reducing it's ability to mow down infantry greatly. Pintle mounted weapons might alleviate the problem somewhat, but this exposes a crewman possibly the commander and hampers his ability to command the tank.

-Gunhead

The defenders are using a mixed bag of tanks (Forge World wanting to sell more models), including a number of Tank Destroyer variants. However, I'll note that they use their tanks mainly for counter-attacks - one of which overruns a Krieg regiment at a critical point and basically nullifies the first major Imperial breakthrough.

[Zinegata]

Not as big as a Bolo or Titan no, though that would be great if you could build it. Something with no more size or firepower then a main battle tank that could fly would be revoltuonary enough, but I’m thinking of a craft in the size and armament range of the Finnish Ilmarinen class coastal defense ships, able to fly 100-200 feet high, sufficient to negate all conventional counter mobility tactics, as well as firing over trees and buildings. Speed would not need to be any better then that of ground vehicles. Bingo, you have armored air cavalry.

Basically the idea is merge the mobility and terrain masking abilities of a helicopter gunship with the firepower and armor of tanks and artillery, and the integrated defenses of a warship. Even if it was not as good as any of those categories in isolation, the combination of effects would be near unstoppable by anything but air power. What’s more, effectiveness would actually increase the worse the terrain gets as its mobility advantage counts for more and terrain masking is easier. 40K seems like it has the technology to do this.

The Tau have vehicles of this description (Manta-class I believe). The Imperium probably has some, but they're not as widespread as giant tracked vehicles - including stuff that are essentially the equivalent of land battleships.

And the only reason why the Tau simply don't win all battles is because they're a puny empire compared to the Imperium - just a few dozen systems.

Artillery fire should really just be destroying all of that, and cratering the landscape so much armored vehicles can’t even counter attack over it. In fact to certain extents it would make actual sense for the Krieg not to be vehicle heavy, if they were very centered in artillery that can blast craters tens of feet deep. Tanks would all get stuck really quickly. Also the attacker has a serious advantage in a circular situation like this, in that his attacks and fires are converging into a narrower area, while the attackers efforts are spread over a divergent path.

See my previous post on how the defenders of Vraks were able to launch an armored counter-attack and make a total mess of the first breakthrough

[Sea Skimmer]

Part 2
I also considered the fact it might be multiple shells (like half a dozen or more) overlapping but I wasn't 100% sure and wanted to factor in the possibility of multiple crater. Gut instinct is that its a single shell from one of the heavier platforms (like the bombard) which is more likely to be ground penetrating. We know from the novel 'Storm of Iron' (which also had siege warfare, only with Space Marines more heavily involved) that Earthshakers can make craters 15 m in diameter, so the idea that conventional artillery blasting out deep craters might be possible.

Diameter of craters is typically several times the apparent depth. Apparent is important; shell and bomb craters are always deeper then they look but fill back in from the dirt raining back down, but even the true depth would almost never be as a great as the width. Blowing wide craters is just much easier than depth, even when you are using emplaced and tamped explosives to blow deliberate craters.

Well if we were going to play the 'nuke game' they should be able to lob melta bombs or demo charges or some heavier munitions in to blow massive holes in the lines. Hell, if they're willing to sacrifice meat droids in such huge numbers wouldn't it make sense to use kamikaze infiltrators like this? I bet a single Krieger could carry alot of munitions on his body...

It would make more sense to just send out a small wave of expendables each morning, and spend the entire day attacking the positions they locate via dieing with deliberate artillery fire and direct fire. If the enemy declines to fire on the advancing forces, then they’ll dig into the first positions they capture and await reinforcements. In this way you steadily push forward, and simply never make the attempt to stage a big attack. This is even more logical if you had a long term plan running. The stories are a monstrously stupid contradiction of vast timeframes and yet somehow urgent attacks.

The Admech is known to have some pretty massive landscaping machines and tech (as big or bigger than the superheavy vehicles like Baneblades.) As a point of reference they're capable of demolishing and levelling mountains and such in a matter of months. I'm sure someone like Black Admiral could give me exact references, I can't remember anything aside from a few cases in the Horus Heresy novels.

Well, we can level mountains in months in real life too, and it doesn’t even take our largest earthmoving machines to do it. Just lots and lots of drilling and explosives. That they actually field such machines in military units make the whole battle that much more stupid. If you had enough big armored bulldozers, in 12 years you could literally just bury the enemy fortifications. Just keep pushing forward a 100-200 foot thick wall of earth and rock with the dozers steadily plowing stuff over the summit

Such a mentality has been ascribed to the siege regiments in this book, up to and including the tanks. Its pretty bad that the Krieg apparently have to be reined in so as not to excessively waste men and materiel in combat, or something stupid.

Its sad that people get paid to write ideas that pointlessly stupid. Why don't they just have every tank self destruct with a grenade while still on its home planet? I'td save an awful lot of resources.

and yes this is contradictory with the Munitorum idea that 'machines and equipment are more important than men.' Hypocrisy is a one of the hidden 'virtues' of the Imperium.

Seems to yet again support my belief that the system just wouldn’t work even in its own retarded universe. Its all just insane.

[Zinegata]

It would make more sense to just send out a small wave of expendables each morning, and spend the entire day attacking the positions they locate via dieing with deliberate artillery fire and direct fire. If the enemy declines to fire on the advancing forces, then they’ll dig into the first positions they capture and await reinforcements. In this way you steadily push forward, and simply never make the attempt to stage a big attack. This is even more logical if you had a long term plan running. The stories are a monstrously stupid contradiction of vast timeframes and yet somehow urgent attacks.

Or they could also assign FOs to follow the expendables and direct the artillery fire. While vox (radio) commuications could often be disrupted by magic (literally), most of the early battles could have been fought under a fairly reliable vox umbrella.

[Sea Skimmer]

Or they could also assign FOs to follow the expendables and direct the artillery fire. While vox (radio) commuications could often be disrupted by magic (literally), most of the early battles could have been fought under a fairly reliable vox umbrella.

You probably wouldn’t even expect to get far enough that observers at your start line can’t do the job. Defenses and deconfliction allowing, you’d also want as many airborne observers as possible. As fixed defenses are eliminated more and more mobile enemy forces have to come forward to be destroyed in turn. It might go like Sugar Loaf Hill for a while, but it’d have the same outcome as well.

[Gunhead]

The defenders are using a mixed bag of tanks (Forge World wanting to sell more models), including a number of Tank Destroyer variants. However, I'll note that they use their tanks mainly for counter-attacks - one of which overruns a Krieg regiment at a critical point and basically nullifies the first major Imperial breakthrough.

Using your tanks to counter attack is something that actually makes sense here. If the enemy gets into your first trench you can just have your arty start blasting at pre measured coordinates with tanks providing direct fire in support to the infantry assault. Against this the enemy pretty much doomed to fail. They are exhausted from their attack, have very little or no heavy weapons, have no prepared positions, enemy knows where all the hardpoints are and fresh reinforcements are still on the way and are subject to artillery / direct fire.

Another thing is, why rely on air vox when you can easily draw landlines? Your attack is advancing at walking pace allowing you to draw huge amounts of cable all around. FO has limited need to move in a static engagement like this. Other options include observation balloons that could even be unmanned. Just stick a high powered camera onto one and lift it into the air tethered to a land line. The only thing limiting the use would be weather.

-Gunhead

[Sea Skimmer]

Its easy enough to lay landlines, but what do you really think the chances are of land lines surviving? They are rather notorious for being magnets for artillery shells, as well as being broke by vehicles and even men tripping on them. Even when buried 4-6 feet deep or laid on the walls of trenches as was typical in the world wars whenever time allowed they had poor survivability. Certainly though, a huge amount of technology easily possible in 40K can be thrown at the issue of communication and observation.

Even simple colored flares can be very effective for calling down preplanned concentrations to defend a lodgement, this became the main way of controlling front line artillery fire in WW1 in many instances since the phones always broke and radios were so clumsy. If anyone ever wrote 'born from birth to fight to death' stuff well they'd have the troops be masters of fire planning and coordinating like this... but no... must make super warriors who only know how to die fearlessly because that's totally the only defining characteristic of good troops. I hear BTW that the IJA took over the whole world sixty years ago.

[Gunhead]

I know about the vulnerabilities of land lines, but I was thinking in the hi-tech approach. I.e "We cannot communicate with our FO base deltafoxtrotnineremprah! Expendables 1, 2 and 3. Take these phones and run them to the base, one of you should get through." If the cable is copperinium, it can be 0.25 mm thick, weigh next to nothing and a single man portable reel can have several kilometers of the stuff allowing single guy draw it while running without fear of it snapping.
Ooh right, I forgot about flares. This gives me an even better idea, coded pulse flares. It's shot in the air and it flashes back a coded message to a receiver that translates it into text. It's very WWI / WWII throwbackish and 40K has a ton of tech that would make it pretty much useless. But hey, it's really GRIMDARK!!
Now if only I could make the flashes look like skulls... Wait, I can! By the power of BS tech, SKULL FLARES FTW!!

I also like your antigrav landship Ilmarinen Skim. Maybe I'm biased . "Landushippu Ilmarinen hasshin!" "Koutei Heika BANZAI!". Oh man, the enemies of mankind would be sooo fucked.

-Gunhead

[Zinegata]

Landlines were extensively used during the First World War, but experience showed that they were cut too easily by enemy artillery fire. Yes, you can send guys out to repair them, but that'd take as long as sending out a messenger and you have to pray he survives in the first place.

I wouldn't expect them to fare any better in the 40K battlefield, and there's no real reason not to simply rely on readily available Vox units.

BTW - Skimmer - you may be happy to note that the Tau (the tiny fringe alien race in 40K) make extensive use of airbornee drones and targeting "lasing" (an actual in-game mechanic) for use against fortified positions, so the technology for the kind of airborne observation certainly exists in the universe - and they basically slaughter the Imperium in another Imperial Armor book.

The Kriegers sadly are definitely on the more "stupid IJA" scale of the equation who are still stuck with 1916 doctrine.

[Simon_Jester]

I don't think the line being really thin or light would do much to make it resistant to enemy fire. It might still be a good idea to have easily portable landlines, but they'd be... sort of a backup to the backup to the backup, because there'd be no point in using them while the radio was working, and in many cases they'd be nothing but a temporary patch for communications, one that would inevitably stop working within a few hours of the time you sent a man out with the wire in the first place.

[Sea Skimmer]

Ooh right, I forgot about flares. This gives me an even better idea, coded pulse flares. It's shot in the air and it flashes back a coded message to a receiver that translates it into text. It's very WWI / WWII throwbackish and 40K has a ton of tech that would make it pretty much useless. But hey, it's really GRIMDARK!!
Now if only I could make the flashes look like skulls... Wait, I can! By the power of BS tech, SKULL FLARES FTW!!

I don't think that even needs BS; near any 2D pattern should be able to be put into a firework style rocket if you felt like it. To be cooler though, make the flare a star cluster so it blows out a whole bunch of small skull bursts.

I also like your antigrav landship Ilmarinen Skim. Maybe I'm biased . "Landushippu Ilmarinen hasshin!" "Koutei Heika BANZAI!". Oh man, the enemies of mankind would be sooo fucked.

Flying all the time sure is a nice defense against swarming melee attacks...automatically defeating a rather large portion of of all enemies in 40K. I can see how given the way 40K logic works, if such ships were common the Tyranids would be given large biological catapults based on giant mutant crickets to fling the melee fighters onto the hulls of aerial warships.

BTW - Skimmer - you may be happy to note that the Tau (the tiny fringe alien race in 40K) make extensive use of airbornee drones and targeting "lasing" (an actual in-game mechanic) for use against fortified positions, so the technology for the kind of airborne observation certainly exists in the universe - and they basically slaughter the Imperium in another Imperial Armor book.

Well, they damn well should. Someone remotely competent with the available technology should go through these fools like the Gulf War, but faster.

I don't think the line being really thin or light would do much to make it resistant to enemy fire. It might still be a good idea to have easily portable landlines, but they'd be... sort of a backup to the backup to the backup, because there'd be no point in using them while the radio was working, and in many cases they'd be nothing but a temporary patch for communications, one that would inevitably stop working within a few hours of the time you sent a man out with the wire in the first place.

No actually no point in using the radio while the landlines are working, unless you love being bombarded by enemy artillery using radio direction finding. Thin and light is very useful so you can lay lots of it, that’s what Gunheat was thinking. If you have the wire, you can just fix breaks by laying new lines which is often much quicker than hunting down breaks to splice. Course 40K should also be able to create networks of small laser communications devices and a few other things, but this would be silly, clearly.

[Alkaloid]

Flying all the time sure is a nice defense against swarming melee attacks...automatically defeating a rather large portion of of all enemies in 40K. I can see how given the way 40K logic works, if such ships were common the Tyranids would be given large biological catapults based on giant mutant crickets to fling the melee fighters onto the hulls of aerial warships.

Apply for a job a Games Workshop. Now. You would make it so awesome.

[Zinegata]

Laser communications do exist in 40K; I recall it being mentioned in some of the Imperial Guard novels as an alternative to vox.

Also, Skimmer would be too sane to be employed by GW.

[Alkaloid]

He came up with giant cricket tyranid manapults. He is not sane.

[Gunhead]

Well damn, Skim beat me to it. Yes that's exactly what I was thinking about the land lines. Even if voxes are the main form of comm, land lines can be produced basically anywhere, though it has been pointed out they should have far better alternative ways off communication if the voxes are down. The other main point was you can make low tech solutions a shit ton better with hi tech and at the same time thematically appropriate if you're looking to emulate a certain style of warfare in fiction.

-Gunhead

[Simon_Jester]

BTW - Skimmer - you may be happy to note that the Tau (the tiny fringe alien race in 40K) make extensive use of airbornee drones and targeting "lasing" (an actual in-game mechanic) for use against fortified positions, so the technology for the kind of airborne observation certainly exists in the universe - and they basically slaughter the Imperium in another Imperial Armor book.

Well, they damn well should. Someone remotely competent with the available technology should go through these fools like the Gulf War, but faster.

They often do, but they're outnumbered so badly that the Tau's idea of "all out offensive" is the Imperial leadership's idea of "mildly depressing nuisance we might or might not remember to do anything about." It also does not help that Tau tactics seem... strangely stylized, in ways that are arguably inefficient. And that their warrior caste is often heavily dominated by the designated ruler-caste.

I don't really know what's going on there.

I don't think the line being really thin or light would do much to make it resistant to enemy fire. It might still be a good idea to have easily portable landlines, but they'd be... sort of a backup to the backup to the backup, because there'd be no point in using them while the radio was working, and in many cases they'd be nothing but a temporary patch for communications, one that would inevitably stop working within a few hours of the time you sent a man out with the wire in the first place.

No actually no point in using the radio while the landlines are working, unless you love being bombarded by enemy artillery using radio direction finding. Thin and light is very useful so you can lay lots of it, that’s what Gunheat was thinking. If you have the wire, you can just fix breaks by laying new lines which is often much quicker than hunting down breaks to splice.

Crap, you're right. Nevermind.

[Darth Hoth]

The Tau are somewhat interesting because they appear (as best I know, at least) to use at least somewhat competent tactics at least somewhat regularly. (Not that they are exactly at Desert Storm levels, either, but at least post-WWII for the most part. 1960s-ish doctrine with vastly less artillery, perhaps?) In the setting of Orks, Space Marines and the Imperial Guard, this makes them fairly unique, even more so than their anime-style aesthetic: While they do have their own fair share of "rule of cool" (mechas, anyone?), their military appears intended to be taken seriously for the most part, rather than as grimdark comedy/parodies of WWI or WWII in space or mediaeval knights with jetpacks. Their doctrine and tech are designed with at least a passing nod to what might be practical or make sense.

I can easily see why the message board debate about them is so love/hate polarised. They represent a fundamentally different approach to the universe than just about every other faction. No sorcery, no demons, no Gothic gargoyles on their spaceships, but what is essentially an "ordinary" space opera power without Warhammer's overt fantasy elements. (Drop them in something like Mass Effect and they would fit right in, save for not being a planet species of hats.)

At its most basic, you have an approximation of a power consistently portrayed as not insane and not hyper-grimdark, in a universe whose entire basis is those things, one that grows out of '80s British absurdist dark comedy in the vein of Judge Dredd, Rogue Trooper and other such 2000 AD comics. No wonder, then, that you have people yelling about them being out of place next to the more familiar rosary-branding crusader knights in power armour.

[Sea Skimmer]

The sorcery and demons and gargolyes are all fine by me, it gives the universe its character, but its just not necessary to have such persistent rampant stupidity of command and tactics beside such fluff if its going to be treated in a remotely serious manner. I do agree the Tau seem much more rational then anyone else now that I have looked into them. This Manta class lander though it still not really what I have in mind, while well armed its clearly designed as an aircraft with little rear facing armament and nothing that appears to be all that heavy.

[Zinegata]

The sorcery and demons and gargolyes are all fine by me, it gives the universe its character, but its just not necessary to have such persistent rampant stupidity of command and tactics beside such fluff if its going to be treated in a remotely serious manner.

The Imperium isn't completely staffed by incompetents though, or else they'd never win a battle. Space Marines tend to have plot armor which means they pull off crazy feats that should be synonymous with "mass suicide", whereas Imperial Guard tend to be more competent depending on the writer.

The Valhallans in the Ciaphas Cain novel for instance are a very modern mechanized force who don't rely on "Send in the next wave!". Likewise, we see highly effective armor formation in the Gaunt novels (particularly Necropolis and Honour Guard). Gaunt in particular retrieves the situation in Necropolis largely by organizing a competent command structure after everyone else above him (who had been playing politics) were disgraced or killed.

I do agree the Tau seem much more rational then anyone else now that I have looked into them. This Manta class lander though it still not really what I have in mind, while well armed its clearly designed as an aircraft with little rear facing armament and nothing that appears to be all that heavy.

The two heavy railguns are technically the most powerful anti-vehicle weapons in the game, while the burst cannons and Ion cannons are very effective anti-personnel weapons capable of throwing down a huge number of shots, at least compared to Imperial weaponry.

If what you're looking for is heavy artillery for dumping HE though (i.e. 155mm gun)... the Tau don't really have them which is one of the blind spots in their arsenal. They really don't seem to like "indiscriminate bombardment" type weapons, and I can't remember them having any kind of tube artillery at all.

Their principal artillery weapon are various "Seeker Missiles", which are missiles guided to the target by lasing (Markerlights) or fired in "dumb" mode. To their credit, they do tend to have a lot of these missiles to make up for any arty shortage.

[Alkaloid]

You shouldn't use the model for the Manta existing as evidence for no one else having a similar piece of kit either. It exists to fill the same gap in the rules and model line up as titans do for everyone else, but we know the Guard have at least one model of lander that can transport at least company worth of troops straight into a fire fight from orbit that we don't get rules for them regardless.

I think what you are talking about skimmer is about the size and armament of an imperial escort, but operating in atmosphere?

Honestly I'm not sure it would work. Having it low enough to avoid fire from the planetary defense weapons would seem to bring it into range of the heaviest stuff they have on the ground, and a vehicle the size you are talking about is going to make even titans look small. Titans are huge but can at least use a building for cover at some point, this thing would always be exposed to enemy fire, and I don't really see what you would get out of it at the sort of altitude to keep it safe from that that ships in orbit couldn't do as well if not better.

[Sea Skimmer]

[
The two heavy railguns are technically the most powerful anti-vehicle weapons in the game, while the burst cannons and Ion cannons are very effective anti-personnel weapons capable of throwing down a huge number of shots, at least compared to Imperial weaponry.

I didn't notice those, if they have them then shrapnel and canister projectiles could deal with softer targets.

If what you're looking for is heavy artillery for dumping HE though (i.e. 155mm gun)... the Tau don't really have them which is one of the blind spots in their arsenal. They really don't seem to like "indiscriminate bombardment" type weapons, and I can't remember them having any kind of tube artillery at all.

That would be a horrible problem. It might actually be realistic for far future warfare, if everyone had C-RAM out the ass, but this is plainly not the case in 40K and in my opinion I'm not going to judge long in the works writing for not having projected it appearing in the last decade.

Their principal artillery weapon are various "Seeker Missiles", which are missiles guided to the target by lasing (Markerlights) or fired in "dumb" mode. To their credit, they do tend to have a lot of these missiles to make up for any arty shortage.

That would help... but its a universe with a lot enemies that just beg for massed bombardments with DPICM.

I think what you are talking about skimmer is about the size and armament of an imperial escort, but operating in atmosphere?

I dunno anything about the 40K spacecraft, never much cared.

Honestly I'm not sure it would work. Having it low enough to avoid fire from the planetary defense weapons would seem to bring it into range of the heaviest stuff they have on the ground, and a vehicle the size you are talking about is going to make even titans look small. Titans are huge but can at least use a building for cover at some point, this thing would always be exposed to enemy fire, and I don't really see what you would get out of it at the sort of altitude to keep it safe from that that ships in orbit couldn't do as well if not better.

No the entire point is that you fly low to the ground, but without the constraints of the actual terrain to hamper your mobility as they will for any ground vehicle or 'hovertanks' that are only a few feet off the ground and could thus still be stopped by trees or a one story house. Such craft would in fact be entirely capable of having a lower profile then a Titan since they don't need to be hundreds of feet in diameter... but if a huge building or a ridge was in the way, they'd be able to rise up to fire over it, then duck back down to avoid counterfire. Ships firing from orbit would presumably have problems with heavy fixed defense as they did on Vraks, and might also have accuracy limitations when firing high power weapons. The fact that Titans work at all is proof out of hand that such ships would be highly effective, and entirely feasible if the required anti grav tech existed, which it seems it does if something like the Manta can be built. A Titan can have its head blown off in situations in which its arm mounted guns would be useless as it crests a horizon. Mr aerial battleship meanwhile would have turrets on the damn top, avoiding the retardation of nearly all mecha of not doing this, and it could mount BIG periscopes to look over obstructions with utter minimal exposure.

Ideally you'd just have space capable warships can that fly into the atmosphere and start blowing stuff up from 50-200 feet off the ground like the Star Wars Victory and Acclamator classes should be able to do, but minus the stupid bridge towers. However issues of cost and design optimization may work against this, so failing that go with a dedicated ship several hundred feet long. A ship like a Acclamator would be extra awesome because if it could break the sound barrier in an atmosphere the shockwaves would create blast damage on par with small nuclear weapons. This makes for a very good close range defensive weapon.