Traveller61 said:

The older fluff specifically mentions accelerations of 50 gravities on a merchant ship (Genestealer game). 40k fluff info has overwhelming shown double and triple digit gravities acceleration. There are some lower outliers but there are also higher outliers as well.

For those less science minded folks, a gravity refers to the force acting on an object on Earth, which is to say an acceleration of 9.8 meters per second squared. That's how fast things fall on Earth. It's a common way of measuring acceleration in science fiction settings.

Given the feel that DH and, we can assume, RT is going for, the acceleration numbers seem good to me. Perhaps the numbers in BG or other sources were a bit high, especially considering that with such high accelerations, reaching the light-speed barrier would actually be doable assuming that the ship is able to carry more then 6 months worth of fuel for continuous burning.

At high velocities, relativity makes you its ***** and the approximations of classical mechanics become grossly erroneously (Newtonian mechancis isn't actually how the universe works, they're just a very good approximation as long as you're travelling no where close to the speed of light). Approaching the speed of light requires a ridiculous amount of energy and actually reaching the speed of light is impossible.

Unless you're a Necron and make the laws of physics your *****.

Graver said:

Sounds reasonable - the ones listed in the preview are, afterall, freighter, pilgrim and ex-service military craft, rather than top-of-the-line marvels of the Omnissiah's blessed technology like the strike cruisers of the Grey Knights, the highly sophisticated pre-Imperial technology of the Imperial Fists fortress monastery (the Phalanx, which would be the station mentioned in Flight of the Eisenstein), or blasphemous nature-defying constructions like the Planet Killer (which was, amongst other things, partially constructed in the Warp and thus not entirely beholden to natural law).

There's room for a wide range of ability when it comes to the construction of ships in 40k, even if you only consider those of the Imperium. A tramp freighter or a retired (in the sense that it's no longer serving in the Imperial Navy) Sword-class Frigate will rarely be as quick through space as an Astartes cruiser or something similar.

Further... we've seen three pages of the starship rules, detailing only the hulls. It seems entirely likely that there'll be the option to give your ship more effective engines to replace the low-end baseline ones listed in the hull entry.

Well since I'm underqualified to comment on 40k physics (although I agree with the statement that sci-fi writers have no sense of scale...) Yeah, this looks pretty good, fairly reasonable compared to what I've seen in the Traveller system and fairly in line with a universe where tanks become landbased battleships and post-human warriors run around like medieval knights. Ships are less trawler or yacht and more ocean liner in scale, all I should say is that the folks at FFG might want to double-check their math to make sure everything makes sense. Other then that... yeah, I'm done.

Cynical Cat said:

Well, I was using slightly sipmlified Einsteinian physics, not Newtonian and, granted, I ignored mass and what would happen to it as it's speed increased and assumed that it would be able to maintain the acceleration rate despite it's increasing mass... but still, gees in the tripple digits might be a bit much. Crossing a decent sized solar system in under a month seems good (and amazingly fast to boot... solar systems are BIG) to me.

Cynical Cat said:

I'd have to say that warp travel in general is making the laws of physics your *****.

"Aww, shucks reality prevents us from reaching a destination in space at the speed of light or faster. That really cramps our style!"

"What if we just simply reject the reality and drive our vessel through an extra dimensional realm of UN-reality?"

"That's not a bad idea mate! Screw the laws of physics! We'll just leave this reality for a while and simply plop out at the other end of the extra dimensional wormhole! All we have to do is manage to dodge the malicious entities in that other dimension where making the laws of physics your ***** is possible."

Then again, the Necrons have made it possible to make the laws of physics their ***** in the material realm, which is a feat in itself...

Cynical Cat said:

Could be that it is like the Move-score in DH, and that different Move-actions use multiples of this. Ie, Half Move, Full Move, Charge, Run, etc.

Darth Smeg said:

I think that might be what the Speed number is for as each hull not only has a max acceleration written in gees but also Speed: some number. Just a bit of speculation...

I'm not talking about the speed number, which has no units and could be anything. I'm talking about the maximum acceleration number which is in gravities.

I'm not saying that high single digit gees is too slow to move around a stellar system, it isn't. I'm saying the numbers are inconsistent with the established universe where the Planet Killer can move across a star system.in hours and a space fortress can pull more than a hundred gees. It won't ruin the game to have lower accelerations and we can handwave them away fairly easy, but the game designers unquestionably dropped the ball with this one.

Cynical Cat said:

Are they inconsistent, though?

We haven't, for example, seen any presence or absence of upgraded engines within the RT starship rules, though I imagine that they're a viable option.

More importantly the two examples you list are far from conclusive in this regard. The Planet Killer, by design and construction, defies natural law - it was, apparently, constructed by the servants of Chaos within the Eye of Terror, where the laws of nature are far looser and more mutable than elsewhere (indeed, there are many in the Mechanicus who believe that it could not have been constructed outside of the Eye of Terror, so impossible is its function). It is, in every sense, a ship capable of things that no naturally-created vessel of similar mass could hope to accomplish, a warp-spawned superweapon rather than an adequate comparison against even the finest of Imperial Navy battleships.

The space fortress in question is the Phalanx, the Fortress-Monastery of the Imperial Fists. It is, amongst other things, an example of pre-Imperial design the likes of which has not been seen since the Dark Age of Technology, as demonstrated by its power, size and mobility. It is, for all intents and purposes, incomparable to any other spacecraft possessed by the Imperium.

In either case, the highly nonstandard nature and origin of these craft make them extremely poor choices against which to compare the capacity of mundane frigates and tramp freighters.

I would like to point out that the acceleration figures are labeled as " maximum sustainable " which does not preclude the ability or option to pull a burn or maneuver of significantly higher G-forces. It is simply the figure for which the ship will remain within safety tolerances. Pull more and the gravity plating/inertial dampers are gonna overstress, as well as the hull, bulkheads and numerous other systems.

A good example would be a modern submarine; say with a dive rating of 1200m, means the sub should not experience any issues up to that depth. Most can go deeper, but the increased pressure causes more and more stress and damage to the hull and other systems until there is a catastrophic failure and the vessel is crushed like an empty aluminium can. In the case of a starship, it would begin to fly apart.

-=Brother Praetus=-

Brother Praetus said:

Quite possible (I think at this moment, most anything is still possible...), though, it doesn't say anything about sustainability. For instance, the Jericho only has: "Accel: 1.6 gravities max acceleration."

Although, now in looking at the stats again, that Speed number I mentioned earlier very well might be the ships initiative score maybe.

Graver said:

True enough, Graver. But read a little further. Starting with the Havoc -class raider and both of the frigates, it includes the word "sustainable." I hope we see corrections in the final print run for consistency.

As to speed, could be.

-=Brother Praetus=-

N0-1_H3r3 said:

1) Those were just two examples I mentioned in that post. It doesn't address my previous examples at all and they still apply. See below.

2) The Planet Killer is known to be slow and unmaneuverable by battleship standards. The main gun is the product of warp craft, but the ship is slow and maneuvers like a pig (Battlefleet Gothic and Execution Hour). It also crosses the inner planetary system and achieves an orbital position suitable for bombardment in hours (which requires deacceleration as well as acceleration which means high double digits gees at the very least and low hundreds being more likely).

3) Battlefleet Gothic has a number of Imperial and Chaos ships with engines that are currently beyond the ability of the Imperium to produce and they still operate on the same scale although with superior performance. Even Necron and Eldar craft maneuvering at sublight, grossly superior in speed and maneuverability to even Dark Age of Technology ships, don't have the kind of differences (two orders of magnitude) you suggest. So no, the Phalanx's origin only suggests it will be faster than other mobile star fortresses. Unless you think that a Necron raider with an inertialess drive which can achieve FTL in normal space can't match the acceleration of a Dark Age star fortress.

4) There are references to merchant ships pulling high double digit gees (Genestealer has one doing 50gees, right off the top of my head) and warships pulling what has to be low hundreds.

So yeah, they screwed up. This doesn't ruin the game, but it is an error.

Cynical Cat said:

Wargame stats are, IMO, never reliable for this sort of thing. Partially because the BFG rules don't deal with acceleration but rather an unchanging abstracted speed value, and partially because of the issues of game balance which constrain the upper limits of what might be possible. A Necron vessel can, through means undetermined, accelerate to faster-than-light velocities... the in-game rules for that are a representative abstraction, hampered by a need to at least nod towards the notions of a fair game.

Novels, on the other hand, are beholden to tell a story first, and pander to the details second. Sometimes the two elements can go hand in hand, but the scales and capabilities of 40k universe spacecraft are so deliberately and universally ill-defined (by way of example: it's taken ten years to get anything even approaching a definitive size for a Sword-class) in 'real' terms that it is and will remain nigh-impossible for there to ever be any consistency in this matter. Starships travel at the speed of plot, with some having faster plots than others.

Cynical Cat said:

First of all, i wouldn't dare to say that these numbers are errors before seeing the whole book. It isn't even stated what a "gravity" is (Terra surface gravity or maybe Imperial standard gravity measured on the surface of Sol). Additionally one of the first paragraphs tells us that players select both a hull and a drive. In the few pages of the preview we only get to see some hulls. This might also explain why some ships have a max acceleration (they might have built-in standard drives) and some have a max sustainable acceleration (the drive must be bought separately and might damage the hull if it is too strong). Note that too strong acceleration can kill the whole crew. These arguments may not be new but i think they are not disproved up to now

I don't want to build up any prejudices against a book of which i have only seen about 1% of all pages.

Did I refer to a stats? Did I quote the Planet Killer's BFG speed rating? No. I refered to in universe background information from novels and games centered around space ships. In universe the Imperial Fleet engages Necron raiders (and usually does badly, but that's Necrons for you), Eldar corsairs, Dark Eldar Pirates, and ancient Heresy era Chaos warships and while all of them are typicially faster and more maneuverable than their Imperial equivalents the difference is not two orders of magnitude. The Planet Killer is slow, both in fluff and stats . Eldar and Necron ships are faster and more maneuverable and so on and so forth, but not to the degree of superiority that is anywhere close to a space fortress having two orders of magnitude of superiority over a fast raider.

Well my whole take on this is.

A. Thank god the ships are big and have large crew compliments!!!

B. If the bigest thing people have to argue about is if the max sustainable acceleration of a ship is to low then they must be doing something right. Since ships move at the speed of the plot anyway.

Big time thumbs up FFG

llsoth said:

Haha, isn't that the truth? The ships always move as fast as the writer finds convenient. Anyway, yeah I am also appropriately impressed with the ships. Certainly seems to be a balance between traders, privateers, and combat-worthy ships. Wonder if there's an Explorator vessel thrown in to give us an idea what the Ad Mech are flying?

Thrudd said:

Inquisitor's Handbook, Forge World Gear, Isotropic Fuel Rods, "A basic building block of Imperium technology,...meter-long metal rods contain a concentrated liquid metal storage medium capable of holding vast quantities of energy. A single fully-charged rod is able to power a small settlement or an entire hab-block for several weeks. ....surviving wonder of the High Dark Age,......"

Not as much space as you might think, though still quite a bit. If you have ever seen the Star Wars cross-sections for the Imperial Star Destroyer or the Acclamator Class, the amount of room the engines and hyper-density fuel storage tanks take up should be about the same as any other 40k ship, at the proper size proportions of course, and with way better technological ideology.