40K misc numbers and analysis thread

[Connor MacLeod]

Ships which need insane amounts of reactions mass are not very realistic.
Of course more realistic than "mass lightening" but only in hard universes with realistic acceleration capabilities. In WH40k they already need technobble to avoid people getting pulped.

They don't need to use or carry much "real mass". Push the velocity of the exhaust up to very close to the speed of light, and you add a shitload of relavatistic mass from all the energy you pumped into it. That's how SW vessels do it, basically.

Also a reaction drive does not necessarily have to do anything with how much power a vessel has available. Nuclear pulse propulsion for example.

At the levels of performance and capability you are talking about, it fucking does. I doubt you could get thousands of gees (or more) of accel out of a nuclear pulse propulsion unit, much less push around starships that are tens or hundreds of millions, or even billions of tons. The energy to push ships around like that has to come from somewhere, and that usually means the main reactors.

If you really want to argue it, I'd just point out that based on some novels the engines of some ships don't quite draw on the full power of the reactors, the same way weapons seem to, so that could be construed as a lower limit if anything.

[Connor MacLeod]

BFG magazine #17

PAge 6

Tau vessels already used a form of gravitic dirve. this projected a sheath of gravitic energy ahead of and around the vessel which was continually re-projected further ahead, drawing the ship behind it rather like an archaic sail.

The Tau seem to have found (or "borrowed") something which resembles a Weberverse gravitic drive (either impeller wedge or the Fasste drive from the furyverse.)


Page 7

Achieving transition to the Warp required more than technology, it required psychically attuned minds and the Tau race boasted no psykers. without them to guide the transition no amount of power could breach the dimensional barriers. The best the Tau could go was make a partial transition, forcing themselves into the void that separated Warpspace and realspacec before they were hurled out again like a ball held under water then released.

...

By carefully angling their descent toward the Warp and extending the field generated by the gravitic drive into a wing, shaped to hold the vessel down a Tau vessel could extend the duration of the dive considerably.

The workings of the Tau FTL drive.

Page 7

Early tests lost several drone ships because they inadvertnatly passed far beyond the sensor range of their recovery vessels.

This could imply FTL sensors, but we know the Tau don't have FTL comms, which makes FLT sensors unlikely.

Page 7

..only the most powerful (and bulky) drives could sustaint eh graivitic wing throughout the dive and the power drain meant that considerabel recahrge time was needed between dives.

Limitations of the FTL drive. Presumably the size constraint was overcome, since Tau manta can equip the drive.

Page 7

Taking typical Imperial warp speeds the Tau drive was slower by a factor of five. The speed was consistent though, did not expose the Tau to the perils of the Warp and enabled the Tau to expand beyond their home star for the first time.

Despite its "advantages", the Tau are goign to be hampered in their expansion unless they can develop faster FTL (nevermind the limits of communication and such)

Page 8

a colonisation fleet was assembled based around seventeen Gal'
leath and twenty-three H'fannor class vessels. Between them these ships could transport some forty Kass'l class gunships.

...

The victory cost the Tau fourteen of their captial ships.

If we assume this represents the fleet assets of a single system, this would imply a fleet of around 4,000 ships.


Page 9

Tau shields are formed by shaping the gravitiic field to repel any incoming fire.

Tau use sidewall- err gravitic fields to repel enemy weapons.

PAge 9

Railguns of the size mounted on warships require massive amounts of energy to fire despite Tau superconductors. Because of this, power is routed to a singel barrel at a time. The sequence is timed to ensure the first barrel is reloaded before it is charged again.

This curiously implies Tau have some hefty power draw limitations with their railguns, which implies a slow recahrge rate (and possibly not a consistent rate of fire.) Perhaps the Tau have limitations on their ability to transfer power from their reactors to weapons - the reactors may have the needed energy, the weapons may be able to use that energy, but the power feeds may not be able to easily/rapidly handle all that energy.

Then again, as I recall the early tau vessels (big blocky dildoes) were crap compared to Imperium designs. The later versions (around the time of the Taros campaign, I believe) were much more impressive (in terms of performance AND looks)

PAge 9

Spine guns are massive railguns where mass drivers trigger the nitial acceleration before the ship's gravitic field is pulsed to squeeze the missiles towards the enemym at enormous speed. The missiles are drone-controlled and exceptionally dangerous.

Tau version of a nova cannon, but with guided munitions. (Although I suspect nova cannon are also guided.)

Page 9

The deflector is a specialised shield generlaly mounted on the prow of the latest Tau ships. It turns the gravitic sheath around the vessle into ad ense wedge, whcih isf ar mroe effective against incoming fire.

Tau equivalent of an Imperium prow. Basically just a stronger shield.

Page 9

Tau missiles are drone-guided and fired in salvos, each point of torpedo strenght representing aobut 10 actual missiles.

Tau use less powerful but more numerous missile volleys. Most ships tend to have "strength 2-8" with the missile/torpedo volleys, which implies between 20-80 missiles. Since they're launched by railguns, this may give us an idea of the number of broadside (or dorsal) guns a tau ship could carry.

It should be fruther noted that these missiles are launched from (IIRC) gravitic launchers, which are railguns with a grav boost, suggesting that the projectiles themselves travel quite fast (significant fraction of c) - probably much faster than normal railguns (Imperial or tau)

Page 10

Based on average speeds using full warp travel, not that average means a great deal, the drive was slower by a factor of five [Explorer/Gal'leath]

Again, difference in FTL speed between Imperium/Tau ships

Page 12

[Il'Fannor/Merchant class] Its reactors were a fraction of the size of the Explorer's power plant but were capable of reaching a third of average warp speed.

Here (advanced?) its implied the Tau drives are merely 1/3 the speed of warp drive, ,rather than 1/5.

PAge 13

The Tau were determined that they should have a ship [Lar'Shi/Hero class] that could match the Imperial Lunar class. As it became evident, they failed..

Earlier Tau warships were less powerful than their Imperium equivalents.

PAge 14

It [Kir'Qath/Defender] can make up to half a dozen warp dives in succession but will then be able to do any more for at least a rot'aa.

...

Unable to build a drive light enough to produce a normal escort the Orca is transported within a capital ship's grravitic sheath. One unleashed ohwever it is a powerful gunship [destroyer?} able to contend with any Imperial or Ork class.

Tau drives seem to have a delay/limited number of uses in a given time period. Also some ships aren't able to carry the drive, so they have to be used as "parasites."

Page 17

Ion cannon shots vaporize the object struck magnifying the energy discharge. Armour is of no value against them. they function as lances in all respects.

I persume "magnifying the energy discharge" refers to the violent effects of work-heating (shock waves causing mecahnical damage in addition to melting/vaporizing thermal damage.) These are the Tau equivalent of lances, and they penetrate armour.


Page 25

Nicassar dhows are small but elegant yachts that are propelled by their captains' psychic powers.

Indication of Nicassar TK strength (at least collective.) If the Tau ever get their asses in gear these guys might be useful against the Imperium. Assuming the Imperium just doesn't exterminate the planet.

Page 28

Despite having vastly more resources than the fleets of Chaos, the Imperial Navy is constantly engaged in war and beset by threat of rebellion and the many natural disasters that befall worlds throughout the galaxy, and as such at any given moment its fleets are spread very thinly, making it extremely difficult for the Imperium to dedicate significant fleet assets to any one star system except in the most dire of emergencies. However, no force in the galaxy can bring to bear the immeasurably vast resources of the Imperium can given enough time

Comparison of resource/industrial capability, fleet sizes, and the such of the Imperium vs Chaos (and other powers.) The flaws of the Imeprium's size and scope are also made evident - if they oculd concentrate on any one threat, they could crush it eaisly. But because they are dispersed dfending their vast territories from numerous smaller threats, they cannot do so (at least not rapidly.) The Imperium stillh as more resources though.

Chaos has a definite advantage over the Imperium defensively in that the Eye is difficult if not nigh impregnable to assault by any covnentional power (in any great numbers, at least.) and that even if someone does invade the inhabitants have tremendous control and influence (An unbeatable home territory advantage.) Which is one thing that allows them, whent hey cooperate to threaten the Imperium - their resources can devote themselves entirely to the offense, and they are able to concentrate better in terms of strriking.

Tau ships are typically equipped with a substnatial number of [railgun] turrets configured for defence against attack craft and torpedoes...

.. you can attach railgun turrets to represent these.

Railgun turrets for poitn defense.

Railguns of the size mounted on warships require massive amounts of energy despite Tau supercondcutors. Because of this power is routed to a single barrel at a time. The sequence is timed to ensure the first barrel is reloted before it is charged again. There are two common styles of railgun - single barreled and double barreld, either of which may be mounted on a ship. Railguns function as stnadard batteries.

Again Tau weapons seem to have limitations in firing large broadsides with their railguns. This suggests that their firepower/rate of fire/concentration of fire is not consistent (kind of like in Age of sial)

[Luzifer's right hand]

They don't need to use or carry much "real mass". Push the velocity of the exhaust up to very close to the speed of light, and you add a shitload of relavatistic mass from all the energy you pumped into it. That's how SW vessels do it, basically.

These are ships which can accelerate to/decelerate from 0.75 c and more.
You just need huge amounts of fuel to get the energy to accelerate your reaction mass that way, that does not really help.
Unless your reactors cheat of course, but why assume that the reactors cheat instead of the drive?

You only seem the notice stuff useful for huge numbers "multi-ton" shells which are moved by people turn into multikilo-ton shells just because they are big for example.
Why not assume that the stated size of nova-cannons and stuff is wrong and not the multi-ton and people pulling them part, or that they just big just for the look, they are mounted on flying cathedrals for fucks sake.
That's a funky kind of cherry picking.

At the levels of performance and capability you are talking about, it fucking does. I doubt you could get thousands of gees (or more) of accel out of a nuclear pulse propulsion unit, much less push around starships that are tens or hundreds of millions, or even billions of tons. The energy to push ships around like that has to come from somewhere, and that usually means the main reactors.

If you really want to argue it, I'd just point out that based on some novels the engines of some ships don't quite draw on the full power of the reactors, the same way weapons seem to, so that could be construed as a lower limit if anything.

No real drive can do that so it does not. That the drive draws some energy from the reactors means nothing at all. Alone for shielding reasons you would most likely need much energy, and of course for internal damping.

[Teleros]

Unless your reactors cheat of course, but why assume that the reactors cheat instead of the drive?

For starters, the systems on most ships seem to utilise the same power source(s). And, given that powering a ship like this with something that vaguely resembles a realistic reactor is going to be difficult, if not downright impossible, then it'd make sense to assume the reactor is cheating, not the drive. That doesn't mean the drive can't be cheating as well, but you pretty much have to have the reactor "cheating" somehow if you're to power even the weapons and whatnot.

You only seem the notice stuff useful for huge numbers "multi-ton" shells which are moved by people turn into multikilo-ton shells just because they are big for example.
Why not assume that the stated size of nova-cannons and stuff is wrong and not the multi-ton and people pulling them part, or that they just big just for the look, they are mounted on flying cathedrals for fucks sake.
That's a funky kind of cherry picking.

Not really. If a shell is of such-and-such dimensions, it's going to weigh a hell of a lot unless it's constructed of some ridiculously light materials. It's far more plausible in my mind to assume that it is that big, and that if necessary the gangs pulling the shell into place etc have some mechanical assistance not mentioned in the passage if required. It also still leaves open plenty of other options (I believe Connor mentioned a nova cannon firing at only something like 30,000km/s at one point).
And just as importantly, you don't have to dismiss sources as "wrong" this way.

[Connor MacLeod]

These are ships which can accelerate to/decelerate from 0.75 c and more.
You just need huge amounts of fuel to get the energy to accelerate your reaction mass that way, that does not really help.
Unless your reactors cheat of course, but why assume that the reactors cheat instead of the drive?

the fuck? Have you actually DONE any research into 40K reactor systems? how much do you know? did you even bother reading the prior pages, because we just got done discussing plasma reactors a few pages ago.

- Squat "neoplasma reactors" being powered by "Warp cores" contained/controlled by a "Zero energy" containment field (Codex Imperialis and the Inquisition War novel "Chaos Child")

- Spacefleet stuff early on indicates plasma fuel is 1000x better than "conveitnonal nuclear fuels", which ought to include fusion if not antimatter. It also implies that plasma fuels are alot more complicated to create than fusion reactants (more akin to antimatter really.)

- Plasma reactors can "re-use/recycle" its fuel mulitple times (Despite being arguably "annilation grade or better" reactors) and have implied insanely long durations (3rd edition rules.. someone posted the excerpt in this very thread.) The ramilies class Star fort has a "hyper plasmatic" energy system that also has an endurance of millenia, which also points to insanely long timeframes.

- Earlier 40K supplements had plasma grenades that involved a "matter/energy transformation process", which is exotic.

- The Last Chancers novel "thirteenth Legion" have all manner of qualities associated with plasma reactors (needing exotic materials working as "catalysts" and "ignition elements"

More than that, it mentions plasma reactors as being a "self fuelling" process. And once you start them up, you don't shut them down. (but you can overload them.) Without its containment fields, a plasma reactor is highly unstable, going into a chain reaction that will utlimately detonate.
What's more, multiple plasma reactors can "fuel" each other's own chain reactions and apparently create larger destruction.

Taken as a whole, with all the other data we know, 40K plasma reactors are VERY exotic, along the lines of stargate Naquadah reactors or Weberverse hyperspace taps (or some theories as to how hypermatter reactors work, actually). Which probably means they are at least partially an extradimensional tap coupled with a conventional reactor (probably feeding the tap and allowing it to occur.)

On top of that, the "stellar levels of energy" needed for a mere cruiser's WARP trranslation are more than ample corroboration for the other figures I've stated. And that has been LONG available in quote form. Nevermind the established acceleration figures, or the recoil bit for the nova cannon (which alone substantiates the magnitude of my calcs, unless you're going to tell me when a ship fires its nova cannon it takes minutes to slow the fuck down too...)

You only seem the notice stuff useful for huge numbers "multi-ton" shells which are moved by people turn into multikilo-ton shells just because they are big for example.

"Muli ton" shells are used in fucking ground artillery in case you didnt notice (First and Only and necropolis.) BFG mentions small MACRO CANNNON hurling around multi ton shells for crying out loud. Its rather fucking obvious that its a whoel lot bigger than that.

Moreover, did you even bother looking at the calcs and the assumptions I put into them? do you think DENSITY OF WATER is at all plausible? Or do you think these are massive 30 meter shells that are virtually empty? I could assume its a 30 meter diameter sphere and still get insanely high end calcs assuming water density. Or maybe you think its got a denstiy slightly higher than air?

On top of that: we know macro cannon/mass driver rounds in the weapons batteries of Imperium cruisers are as large as a "marauder", which in the same short story (by Gav Thorpe, incidentally) are MORE than triple the mass of a "battle tank". The rennie BFG novels also mention the ork weapons batteries huhrling shells the size of fighters or bombers (IE the hundreds of tons range)

Torpedoes (which are, by the evidence I have thus far presented, the closest we might get to nova cannon size) are EASILY 10x more massive in the shortt story, and that's for cruiser grade torps, nevermind what a battelship might pack. BFG makes mention of "skyscraper" sized torpedoes, which probably are more on the scale of what a nova cannon shell as well. At the very minimum you can expect a nova cannon shell to be many THOUSANDS of tons at the minimum, ,and even then its not going to be very large compared to a thirty (nevermind the fifty meter diameter) nova cannon shells.

In short, by the fuckinvg evidence I have accumulated in my research, I've seen ample justification for my figures. You, on the other hand, seem only able to quibble over the interpretations without bothering to look at the reasoning or consistency.

Why not assume that the stated size of nova-cannons and stuff is wrong and not the multi-ton and people pulling them part, or that they just big just for the look, they are mounted on flying cathedrals for fucks sake.
That's a funky kind of cherry picking.

Yet again, do you ever bother to think about shit before you ay it, or are you just trying to be a condescending asshole making broad accusations of dishonestY? I don't really fucking appreciate being called dishonest when you eivdently haven't even bothered to pay attention or read the fucking thread. Nevermind what I just posted above which indiciates my justifications (nevermind validating them.)

As for the "pulling"shit, ,did you read the fucking quote?

...to accept the massive, multi-ton shell being trundled into place by more lash-motivated gangs pulling on an enormous overhead gantry under the careful eye of gunnery chiefs and Mechanicus adepts.

Trundling it into place indicates there's something UNDER the shell to faciliatte its movement (guess you just assumed they pulled it across the bare metal decking, huh?) Moreover, ,the mention of a Gantry would imply cranes being involved. If that's not enough, we dont even know how many men are involved, what kinds of augmentations they may or may not have, or even the kinds of equipment being used to do the hauling. Or are you going to tell me things like suspensors or other antigrav (which the guard have access to handily, nevermind the navy) or cybernetic augmentations are super rare among naval crews?

In fact, given the fifty meter diameter Nova cannon shell in Warriors of Ultramar needing to be artificially lifted by machinery, I think its a fairly safe bet that its nothing at ALL like you try to make it out to be. In short, I have sufficient proof to cover my ass. you simply have nitpicking and accusations. Maybe you'd care to bring some counter-evidence, or care to provide proof of my supposed dishonesty?

No real drive can do that so it does not. That the drive draws some energy from the reactors means nothing at all. Alone for shielding reasons you would most likely need much energy, and of course for internal damping.

Since I'm a little tired of your guerilla sniping, whyh don't you provide some fucking proof and calcs to back up your assertions. I'm a little tired of you taking potshots at me without bothering to back up any of your shit. and I've got very little patience for this right now.

[Luzifer's right hand]

Did I claim that you calcs were wrong? I claim that the how you select the numbers you use in your calcs are highly questionable.

You use the stuff the writers created("stellar levels of energy" and so on) which are suitable for huge numbers. However you happily ignore the stuff which is not suitable for huge numbers like low masses for ships.
It's of course clear that the writers to not know what they are writing about, but either you accept everything or nothing, not just what suits you.

[NecronLord]

By definition, if a ship is capable of putting out e23 J, it is capable of putting out gigawatts. A hell of a lot of them, but still. Unless the high end is outliers, you go with the high end. This is why the guns on Geonosian fighters are given a higher power rating in AotC ICS than they appear to display in the film (dinky divots of sand anyone?) for example.

[Connor MacLeod]

Did I claim that you calcs were wrong? I claim that the how you select the numbers you use in your calcs are highly questionable.

You accused me of cherry picking. How am I supposed to take that as anything but an indication of dishonesty on my part, pray tell? I doubt you could be thinking I would be so ignorant as to be unaware of what I was doing, so it would have to be DELIBERATE.

You use the stuff the writers created("stellar levels of energy" and so on) which are suitable for huge numbers. However you happily ignore the stuff which is not suitable for huge numbers like low masses for ships.

Yes, because a ship the size of an ISD is going to plausibly be 100,000 tons. The Honorverse had ships of that size that were FAR more massive (heavy cruisers were on the order of 1200 meters IIRC, and Battlecruisers close to a mile long.. the former were ~300,000 tons and the later close to 900,000 tons) yet their densities were abusrdly low (and were hence rescaled.) Even at a mere 500 meter long "Raider". is going to mass far more than 100,000 tons at any reasonable density.

I'm not even going to venture onto the idea of a 1 million ton, 4 mile long battleship (nevermind the whole "inside the eye of terror and moving at FTL speeds in normal space wonkiness and how that might even begin to foul up mass figures and rammings.) In cae you haven't noticed, I have provided MULTIPLE reasons why I ignored them in various cases - they're never absolute, even disrearding the mass/volume/density absurdity.

Do you have any actual legitimate arguments to put forth, or are you going to keep nitpicking?

It's of course clear that the writers to not know what they are writing about, but either you accept everything or nothing, not just what suits you.

Neverminding the "outlier" point Necronlord mentions, I like how your interpretation assumes that Sci fi analysis is an "all or nothing" approach. See by your logic, dialogue must be taken at absolutely face value no matter what (the usual argument of the "dialouge over visuals crowd, IE TDIC) or that visuals are merely SFX and shouldn't be calced (usually the same crowd.) Additionally, as Necronlord points out, not only does consistency matter, but "lower end" examples can be accounted for more easily than higher end examples (a energy weapon that can fire gigatons of energy can also fire megatons or kilotons arguably. A weapon limited to KT or MT cannot fire gigatons as easily or plausibly.)

Sci fi analysis is not nearly as straightlaced as you make it out to be, You don't fucking believe me, ask Mike.

Moreover, I do and redo many of these calcs as new information comes to light or as I figure out new things. Lasgun calcs, ,the Caves of Ice calcs, and nova cannon/bombardment calcs have all been done this way. Many of the calcs in this very goddamn thread have followed that pattern. You can only calc shit when you have the variables at hand, and many of the supposed "low end" examples I get tossed into my face are either vague as hell or the person doing it has no fucking clue how to analyze shit.

Lastly, I am not aware of having "ignored" anything obviously or directly quantifiable that suggests lower numbers, aside from the "gigawatts" Necronlord mentioned (Which is so obviously ludicrous, given the most conservative calcs place man portable weaponry the Guard uses well into the gigawatt or higher range, nevermind anything like artillery or tank guns)

So again, you want to claim I am ignoring shit, provide your evidence and examples of what I am "ignoring"

[fusion]

Since this is the Misc. calc thread for 40K: How big and how much power are the Baneblade's main cannon, the Mega Battle Cannon?

[Connor MacLeod]

Since this is the Misc. calc thread for 40K: How big and how much power are the Baneblade's main cannon, the Mega Battle Cannon?

At the moment? No fricking clue. More powerful than a regular battle cannon or Conqueoror.. I'd guiess at least several times more so, but that's just a guess.

Bear in mind that the recoil/impact of the weapon isn't the same as the explosive power.

If I were to dig into my mind, the Forgeworld suppelments gave one of the superheavies a 180 kg projectile. Assuming a muzzle velocity of around 1000-1500 m/s for a MBC, that's going to be several hundred thousand kg*m/s worth of momentum in the shell. and around 90-200 MJ worth of KE. That could be conservative, as I remember MBC also being noted to use rocket-assisted cannons to boost speed (so it could be even higher.) and that doesn't factor in any explosive payload. Assuming 1/3 the mass in simple TNT, , that oculd easily be another 200-300 MJ worth of enegy.

Again that's all conjecture based on forgeworld and the definition of a "hypervelocity" round (what conqueror cannons fire in Honour Guard), its not direct or stated, ,but it should probably mesh with what we already know elsewhere.

[Connor MacLeod]

Before I post the next update...

I've decided that maybe I need to give a fucking reason WHY I chose to interpret the "multi-ton" nove cannon calc the way I did, since certain people think I "cherry pick" what I use. Thus I will also confine this to analysis of the quote in question (Because even disallowing other evidence being brought to bear, the quote itself is fairly straightforward to analyze.)

For reference, I'll lay down the quote once more:

Deep within the bowels of the ship, archaic weapons of unimaginable power hummed to life, and the Master of Gunnery personally supervised the loading of the awesome Nova cannon as gangs of men numbering in the dozens opened the thirty-meter wide breech to accept the massive, multi-ton shell being trundled into place by more lash-motivated gangs pulling on an enormous overhead gantry under the careful eye of gunnery chiefs and Mechanicus adepts.

There are three potential indicators as to the mass of the projectile.

The first, of course, is the "thirty meter diamter". One can get a good lower limit estimate (as I did) by estimates of the diameter coupled by the probable shape/length of the thing (treating it as a sphere or short cylinder is conservative, much less like say, a pistol bullet.) This is very straightforward and at its most conservative requires few unreasonable assumptions.

Secondly, there is the "multi-ton" shell reference . Frankly, this is rather vague. Were I inclined to be ridiciouslyl consevative, I could couple a 2 ton mass with the near-c quote, but that would be ridiculous for many reasons . As I've already noted, there are numerous other soures indicating that 2 tons is absurdly tiny for a nova cannon shell, but there is a more immediate reason why it would be absurd, and that is the diameter of the shell. There is no possible, plausible way for a 30 meter diameter shell to weigh 2 tons, unless it was a very thin, 30 meter diameter disc the density of air (or almost completely hollow.) None of that is plausbile in the least, and by itself "multi-ton" can mean any sort of tonnage, just because "two tons" is a lower limit does not mean it is automatically the right one. The lager projectiels I estimated (thousands/tens of thousands of tons) can also be argued to be "multi-ton" as well, even if this is a looser interpretation.

Thirdly, there is the "men pulling the shell into position". This, too, ,is too vague to be quantifiably useful. We know they're pulling somehow, but we don't know how they are doing it. It does suggest "assisted" pulling, but whether it is or isn't just adds mroe complicaton to the issue. We don't know how many men are pulling, either, nor what the conditions/capabilities of the men are, ,or what assistance they may have individually (IE augmentics.) By itself, the quote tells us nothign we can use to determine pulling, unless we do the absurd "low end" again of 2 gangs of 2 dozen men each (48 men) which suggests a shell of the same tonnage as the "multi-ton" quote (but also has the same problems.)

But what if we brought other information to bear? Let's assume a crew of 20,000 (an upper limit suggested by the Soul Drinkers novels for the largest Battleships, even though other sourecs have suggested larger, and cruisers alone carry half that complement and being a fraction of the volume.)

We further know that in a cruiser of unknown size (crew close to light cruiser/heavy cruiser displacement) they had an estimated crew of "hundreds" to a thousand hauling torpedoes (which could weigh ten times the mass of a marauder fighter, which itself was 3x the mass of an MBT) For a battleship, we'll call it 2,000.

Furthermore, to be conservative, we'll ignore any augmentics. We'll allso ignore the fact that, as many sources have demonstrated, such as Necromunda, the Ghost novels, etc.. there exist many individuals who are stronger than your average real life human, many of them vasty stronger than even those individuals (such as Bragg, who can lift heavy bolters, or the Heavies or Goliaths from Necromunda.) I will also ignore the possibility of any "assistance" - I will assume they are simply pulling or pushing a shell across the bare floor, despite this being ludicrous.

Being lazy, I decided to check Wikipedia here for weightlifting values. Under "records", it generally indicates a skilled individual can lift between 4-6x his or her body mass. I will generally assume 2x body mass for "untrained" individuals, again being conservative. Assuming a roughly 75 kg man (even though Imperium humans can be larger), this translates to 150 kg. This, by itself, means that 2000 people should be able to push/pull a 300,000 kg (300 ton) shell into position.

That is a purely conjectural estimate, of course, and nowhere near what I estimated for the size, but it also fails to account for the fact I've ignored countless things that would revise the figure upwards. Hell I assumed they were simply lifting the shell straight up, even though pushing or pulling on it, even without assistance, shoudl be easier (much less "trundling" into position, which would suggest the use of wheels.)

Timeframe and distance also play factors, but are also unknowns. The more time they have, the more effort can be used in pushing the shell into position (and can allow for bigger shells to be hauled.) This is to say nothign that even at 300 tons, a 30 meter long, thirty metre diameter "disc" would only be 14x more dense than air at that mass, which is still fairly silly.

Given all that, its more probably likely that a nova cannon shell would mass no less than thousands of tons, if not tens of thousands of tons, which accords with all the other known facs (particularily given that six cruiser-class torpedoes would togehter mass more than several thousand tons, easily, and that you trade in six torps for one nova cannon in most cases, even if you didnt "scale up" for a battleship's nova cannon.)

And this, of course, is why I did the calc the way I did. And now shown that, even doing it the other way, I could still reach the same figures. I could have still been "conservative" I suppose, but again given the totality of known facts in the source material, doing so would be silly to the point of redundant (the same way that bothering with the Pre-ICS calcs when we have the established ICS figures are - they're simply a curiosity, nothing more.)

[Connor MacLeod]

BFG magazine #17

PAge 6

Tau vessels already used a form of gravitic dirve. this projected a sheath of gravitic energy ahead of and around the vessel which was continually re-projected further ahead, drawing the ship behind it rather like an archaic sail.

The Tau seem to have found something which resembels a Weberverse gravitic drive (either impeller wedge or the Fasset drive from the furyverse.)


Page 7

Achieving transition to the Warp required more than technology, it required psychically attuned minds and the Tau race boasted no psykers. without them to guide the transition no amount of power could breach the dimensional barriers. The best the Tau could go was make a partial transition, forcing themselves into the void that separated Warpspace and realspacec before they were hurled out again like a ball held under water then released.

...

By carefully angling their descent toward the Warp and extending the field generated by the gravitic drive into a wing, shaped to hold the vessel down a Tau vessel could extend the duration of the dive considerably.

The workings of the Tau FTL drive.

Page 7

Early tests lost several drone ships because they inadvertnatly passed far beyond the sensor range of their recovery vessels.

This could imply FTL sensors, but we know the Tau don't have FTL comms, which makes FLT sensors unlikely.

Page 7

..only the most powerful (and bulky) drives could sustaint eh graivitic wing throughout the dive and the power drain meant that considerabel recahrge time was needed between dives.

Limitations of the FTL drive. Presumably the size constraint was overcome, since Tau manta can equip the drive.

Page 7

Taking typical Imperial warp speeds the Tau drive was slower by a factor of five. The speed was consistent though, did not expose the Tau to the perils of the Warp and enabled the Tau to expand beyond their home star for the first time.

Despite its "advantages", the Tau are goign to be hampered in their expansion unless they can develop faster FTL (nevermind the limits of communication and such)

Page 8

a colonisation fleet was assembled based around seventeen Gal'
leath and twenty-three H'fannor class vessels. Between them these ships could transport some forty Kass'l class gunships.

...

The victory cost the Tau fourteen of their captial ships.

If we assume this represents the fleet assets of a single system, this would imply a fleet of around 4,000 ships.


Page 9

Tau shields are formed by shaping the gravitiic field to repel any incoming fire.[

Tau use sidewall- err gravitic fields to repel enemy weapons.

PAge 9

Railguns of the size mounted on warships require massive amounts of energy to fire despite Tau superconductors. Because of this, power is routed to a singel barrel at a time. The sequence is timed to ensure the first barrel is reloaded before it is charged again.[//quote]

This curiously implies Tau have some hefty power draw limitations with their railguns, which implies a slow recahrge rate (and possibly not a consistent rate of fire.)

PAge 9

Spine guns are massive railguns where mass drivers trigger the nitial acceleration before the ship's gravitic field is pulsed to squeeze the missiles towards the enemym at enormous speed. The missiles are drone-controlled and exceptionally dangerous.

Tau version of a nova cannon, but with guided munitions. (Although I suspect nova cannon are also guided.)

Page 9

The deflector is a specialised shield generlaly mounted on the prow of the latest Tau ships. It turns the gravitic sheath around the vessle into ad ense wedge, whcih isf ar mroe effective against incoming fire.

Tau equivalent of an Imperium prow. Basically just a stronger shield.

Page 9

Tau missiles are drone-guided and fired in salvos, each point of torpedo strenght representing aobut 10 actual missiles.

Tau use less powerful but more numerous missile volleys.

Page 10

Based on average speeds using full warp travel, not that average means a great deal, the drive was slower by a factor of five [Explorer/Gal'leath]

Again, difference in FTL speed between Imperium/Tau ships

Page 12

[Il'Fannor/Merchant class] Its reactors were a fraction of the size of the Explorer's power plant but were capable of reaching a third of average warp speed.

Here (advanced?) its implied the Tau drives are merely 1/3 the speed of warp drive, ,rather than 1/5.

PAge 13

The Tau were determined that they should have a ship [Lar'Shi/Hero class] that could match the Imperial Lunar class. As it became evident, they failed..

Earlier Tau warships were less powerful than their Imperium equivalents.

PAge 14

It [Kir'Qath/Defender] can make up to half a dozen warp dives in succession but will then be able to do any more for at least a rot'aa.

...

Unable to build a drive light enough to produce a normal escort the Orca is transported within a capital ship's grravitic sheath. One unleashed ohwever it is a powerful gunship [destroyer?} able to contend with any Imperial or Ork class.

Tau drives seem to have a delay/limited number of uses in a given time period. Also some ships aren't able to carry the drive, so they have to be used as "parasites."

Page 17

Ion cannon shots vaporize the object struck magnifying the energy discharge. Armour is of no value against them. they function as lances in all respects.

I persume "magnifying the energy discharge" refers to the violent effects of work-heating (shock waves causing mecahnical damage in addition to melting/vaporizing thermal damage.) These are the Tau equivalent of lances, and they penetrate armour.


Page 25

Nicassar dhows are small but elegant yachts that are propelled by their captains' psychic powers.

Indication of Nicassar TK strength (at least collective.) If the Tau ever get their asses in gear these guys might be useful against the Imperium. Assuming the Imperium just doesn't exterminate the planet.

Page 28

Despite having vastly more resources than the fleets of Chaos, the Imperial Navy is constantly engaged in war and beset by threat of rebellion and the many natural disasters that befall worlds throughout the galaxy, and as such at any given moment its fleets are spread very thinly, making it extremely difficult for the Imperium to dedicate significant fleet assets to any one star system except in the most dire of emergencies. However, no force in the galaxy can bring to bear the immeasurably vast resources of the Imperium can given enough time

Comparison of resource/industrial capability, fleet sizes, and the such of the Imperium vs Chaos (and other powers.) The flaws of the Imeprium's size and scope are also made evident - if they oculd concentrate on any one threat, they could crush it eaisly. But because they are dispersed dfending their vast territories from numerous smaller threats, they cannot do so (at least not rapidly.) The Imperium stillh as more resources though.

Chaos has a definite advantage over the Imperium defensively in that the Eye is difficult if not nigh impregnable to assault by any covnentional power (in any great numbers, at least.) and that even if someone does invade the inhabitants have tremendous control and influence (An unbeatable home territory advantage.) Which is one thing that allows them, whent hey cooperate to threaten the Imperium - their resources can devote themselves entirely to the offense, and they are able to concentrate better in terms of strriking.

Tau ships are typically equipped with a substnatial number of [railgun] turrets configured for defence against attack craft and torpedoes...

.. you can attach railgun turrets to represent these.

Railgun turrets for poitn defense.

Railguns of the size mounted on warships require massive amounts of energy despite Tau supercondcutors. Because of this power is routed to a single barrel at a time. The sequence is timed to ensure the first barrel is reloted before it is charged again. There are two common styles of railgun - single barreled and double barreld, either of which may be mounted on a ship. Railguns function as stnadard batteries.

Again Tau weapons seem to have limitations in firing large broadsides with their railguns. This suggests that their firepower/rate of fire/concentration of fire is not consistent (kind of like in Age of sial)

[Lost Soal]

For material masses, If I recall the numbers correctly than the dimensions and masses of tanks (which have been consistent between novels and IA) tend to indicate that the Imperiums battlefield materials tend to mass approximately 1/3rd that of Iron. Therefore the ships and shells will mass less than expected for their sizes, just not to the low extremes that are being suggested.

[Cykeisme]

For material masses, If I recall the numbers correctly than the dimensions and masses of tanks (which have been consistent between novels and IA) tend to indicate that the Imperiums battlefield materials tend to mass approximately 1/3rd that of Iron. Therefore the ships and shells will mass less than expected for their sizes, just not to the low extremes that are being suggested.

"Battlefield materials"? Assuming you're referring to density rather than mass, these numbers (if accurate) would primarily be referring to the density of the armor and structure of the vehicles in question.

There is no reason to assume that shells would be composed of similar materials with similar densities. Are shells fired by aircraft-mounted cannon made of aluminium? Or are tank hulls made of solid depleted uranium?

[Falkenhayn]

BFG magazine #17

PAge 6

Tau vessels already used a form of gravitic dirve. this projected a sheath of gravitic energy ahead of and around the vessel which was continually re-projected further ahead, drawing the ship behind it rather like an archaic sail.

The Tau seem to have found something which resembels a Weberverse gravitic drive (either impeller wedge or the Fasset drive from the furyverse.)

Are there advantages to gravity based defenses? Weber likes to state how wedged and sidewalled ships are immune to KE and Momentum. Is that technobabble?

[NecronLord]

Are there advantages to gravity based defenses? Weber likes to state how wedged and sidewalled ships are immune to KE and Momentum. Is that technobabble?

Verily. He has a weird cosmology set up to back that up.

[Imperial Overlord]

The Tau seem to have found something which resembels a Weberverse gravitic drive (either impeller wedge or the Fasset drive from the furyverse.)

Are there advantages to gravity based defenses? Weber likes to state how wedged and sidewalled ships are immune to KE and Momentum. Is that technobabble?

All the cool shit associated with Weber's tech (invulnerable wedges, uber sidewalls, free energy, etcetera) is all authorial fiat to get his universe working like he wants it to (i.e. to be a soft sci-fi version of the age of sail complete with crossing the T and broadsides).

[Connor MacLeod]

For material masses, If I recall the numbers correctly than the dimensions and masses of tanks (which have been consistent between novels and IA) tend to indicate that the Imperiums battlefield materials tend to mass approximately 1/3rd that of Iron. Therefore the ships and shells will mass less than expected for their sizes, just not to the low extremes that are being suggested.

Well I'm using water (or if I'm feeling perverse, 1/10th water if I'm insane) scale density, so I'm alot less than that

"Battlefield materials"? Assuming you're referring to density rather than mass, these numbers (if accurate) would primarily be referring to the density of the armor and structure of the vehicles in question.

There is no reason to assume that shells would be composed of similar materials with similar densities. Are shells fired by aircraft-mounted cannon made of aluminium? Or are tank hulls made of solid depleted uranium?

I suspect he was just suggesting an analogue. And its not unreasonable from a consevative POV either - alot of weapons shells are noted to be as large/massive as fighter or tank platforms (or more massive.).

In truth we don't know quite WHAT the composition of the shells is, which is why I generally don't assume 100% iron I could assume 10% iron, or 1%, but 1000 kg*m^3 density seems like it would more reasonably cover the entire volume (I can't think of any RL explosive that might be substnatilaly less dense, really.)

[Connor MacLeod]

Are there advantages to gravity based defenses? Weber likes to state how wedged and sidewalled ships are immune to KE and Momentum. Is that technobabble?

No. tHey're probably no more "real" gravity than weberverse drives are or Vongwank dovin basals. And in any cae, Conservation of momentum still applies. And I'm pretty sure Tau shields still degrade like void shields do.
I simply was making the WEberverse analogy because the defenses are derived from the drive system (shaping the drive system IIRC) which is like alot of weberverse drives.

The closest they have to a sidewall/wedge is the Bow deflector thingy, which is basically a forcefield version of the armoured prow of an Imperial warship.

All the cool shit associated with Weber's tech (invulnerable wedges, uber sidewalls, free energy, etcetera) is all authorial fiat to get his universe working like he wants it to (i.e. to be a soft sci-fi version of the age of sail complete with crossing the T and broadsides).

Well thats what its supposed to be in theory. In practice its mainly because Weber uses plasma nukes for the contact warheads and his gravity wedges behave like a solid wall (any object striking basically vaporizes.) Its worth noting they do NOT ignore conservation of momentum, so its probably quite easy to buckle the sidewall generators with a sufficiently nasty impact. Even the Impeller wedges probably could buckle.

[Connor MacLeod]

Last BFG magazine updates.. about fucking time too.

BFG magazine #18

Page 9

The Imperium's defenses were thinly spread, even around hte Caidan Gate where the so called Bastion fleets stand as the largest permanant Imperial Navy element outside of the Solar System.

Sol System's naval forces are larger than the bastion fleets around the Cadian gate (meaning many hundreds of vessels, possibly thousands.) Presumably this means only naval ships, not including the Inquistion, Arbites, AdMech, or Astartes vessels that might be there.

PAge 10

Where the Imperial Navy had been forceed to divide its assets across hundreds of worlds at the outset of the war.

...

Where Imperial defences had been overstretched at the outset of the war, they soon stood reinforced by dozens of neighboring battlefleets. Tiny patrols, at first hopelessly outnumbered nad overwhelmed by Abbadon's invasion, mustered together into battlefleets numbering hundreds of vessels.

...

To win the greater war now the wise (and not least amongst them, Admiral Quarren) realised that a handful of crucial fronts must be all to which the Imperium committed.

Description of the Imperial dispostion of forcees and how it altered with the onset of the 13th Black Crusade, and how it influences tactics.


Page 14

...Space Marine Honor Guard companies failed to prevent hte Planet Killer firing, but damaged its shields. As a consequence, debris from the shattered world struck the Planet Killer, which was last seen tumbling away into wilderness space critically damaged.

The Planet killer was struck and damaged severely by debris from one of its own victims.


Page 15

Faster escort squadrons ploughed on ahead, hoping to inflict critical damage on the Blackstone, but most were vapourised instantly by its booming warp cannons.

faster (and thus smaller?) escorts were vaporized rapidly by the Blackstone.

Page 15

with Chaos fleets being caught ill-prepared as they hung in orbit over a dozen worlds, disgorging the hordes within.

Indicates the Imperium struck at a dozen different planets (out of a Thousand potential, or "hundreds") attacked by Chaos.

---

BFG magainze #19

Page 5

Under such circumstances, a Rogue Trader may even be called upon to lead an expeditionary force without an attendant fleet, perhaps numbering several dozen vessels.

It seems that on the high end of things a Rogue Trader may command "severla dozen" vessels, which we may take to mean between 24-40 ships./

Page 6

Rogue Traders typically favour vessels which make use of alien energy tehcnology, since the huge power supplies and impossibly difficult upkeep needed for the Imperium's own laser and lance weaporny generally makes them unusable by Rogue Traders, isolated, ,as they often are, for yers at at ime, far from Imperial docks.

Curiously, this implies that Imperium laser/lance weaponry is more powerufl (raw firepower) than most alien weapons. The upkeep part is also curious, since Imperial ships are designed to be, among othe things, mobile foundaries for the reason they DO operate way from base for extended periods.

PAge 6

Although these weapons are described in simple terms as weapons batteries and lance batteries, they actually represent a whole gamut of alien weaponry such as ion cannons, jokaero laser technology, fusion generators or otehr weapons of indeterminate origin.

No idea what a "f usion generator" is, but jokaero lasers seem to be different than Imperial lasers. Also, the Imperium doesn't use ion cannons (if they do use particle beams, ,they're something else than CPB's then.)

PAge 7

Most admirals are more than happy to have a ship or two of their own acting in concert with any Rogue Traders in tehir employ, not least because they are likely to trust their own escort crews rather more than they trust the Rogue TRaders.

at any time a handful of ships may be assigned to serve with Rogue Traders.

Page 8

.. in less than a thousand years their sphere of influence swelled to eight primary worlds and several dozen additional systems. As time progressed, thse major worlds, or Septs as they are known to the Tau, began establishing their own expeditions of colonisation and conqeust...

The Tau have at least 30-50 planets under their sway.



page 8

As most of these [alien races] only existed on one or a very small number of habitable worlds, they were easily incorporated as subject races in the Empire.

tau "recruitment" policies.

Page 11

hulking manta missile destrtoyers, bombers that were nearly escort-sized in their own right.

This probably suggests the Mantas are several hundred metres long, since the smallest escrots known are around half a kilometer or so. I'm pretty sure the Imperium has fighters and drop ships close to this sczle too (some of the larger ordnance/attack craft.)

[Teleros]

Pics of the Manta. Unless the Tau have another, larger Manta design, I'm guessing the "escort-sized bombers" are separate to the Mantas. I'd be very surprised if the Imperium uses escorts that small...

[andrewgpaul]

The photos on page 2 of that link Teleros posted give a better sense of scale.

I think there's mention of the sizes of the Navy fighters and bombers (Furies and Starhawks) somewhere in the BFG material. I think they're similar in scale to Mantas. This is a comparison of a BFG-scale Manta with a space-adapted Barracuda.

[white_rabbit]

You'll find that like many other things, the manta has shrunk slightly from its original concept, simply because they wanted to make a model of it, then the "model" often becomes the more exposed image, and thats the end of the "escort" sized Mantas.

[Falkenhayn]

*possibly some spoilers below*

This is some calc fodder for anyone with the inclination and know-how.

The setting:

Armor of Contempt, p. 109-111

"Along the west coast, down the line of seaboard towns and cities that had been linked and fortified into one long snake of battlements called K'ethdrac, or K'ethdrac'att Shet Magir, the sky went white...There was no wind, and everything was hushed. Visible static charges gathered like ivy around the raised barrels of the weapons assemblies standing read all along the seventy kilometer long fortress".

This fortified region above will be the target of the Imperial Navy's preperation.

"The first strikes were like rods of molten glass, blue hot, there and gone again in a nanosecond. The cloud cover they came through was left wounded and supperating light. Where they touched, the ground vaporised into craters thirty meters wide. Bulwarks, armored towers, thick barriers of metal and stone all vanished, and with them, the gun batteries and crews that had been stationed there. Nothing was left but fused glass, lignite ash and deep cups of rock so hot they glowed pink. Each strike was accompanied by a vicious atmospheric decompression that sucked in debris like a bomb blast running backwards".

There's no indication on whether these strikes were from Lances or Plasma batteries.

Now, the next bit is about the physical effects of IoM warships on planets in close proximity, and the environmental effects of what looks like a pretty "mundane" planetary invasion.

Armor of Contempt, p. 309

"Gaunt nodded. He knew it was the invasion that had triggered the storm. You didn't dump such catastrophic amounts of mass and energy into an atmosphere without the weather patterns flying apart. He remembered Balhaut, Fortis Binary, and most recently, Ancreon Sextus. It wasn't just the heat exchange of weapons use, it was ship drives in low orbit, gravity generators, overpressure, and atmospheric insertions. This rainstorm in Lowensa province was due in part, to the null fields of capital ships squeezing the air over the ocean at Gereon's tropics, to the global warming of orbital barrage, to the rapid air displacement of a hundred thousand drop ships".

Null fields apparently project some distance from the actual ship. Also, the reference to a "Null Field" is new to me, as opposed to a Gellar Field or Void Shielding. I haven't got a clue what it does.

[Imperial Overlord]

Null fields are mentioned in the novel Eye of Terror. They are stealth devices that hide ships.