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15-03-2013, 11:23
Normally how much time a ship needs to go e.g. from the fringe of a system to an inner planet? A couple of hours? Days? Weeks?
And what is their actual speed? I know that there is hardly a speed limit in space (expect for lightspeed, of course), but they must have a common operational speed (depending on the class and the size of the particular ship).

Lothlanathorian
15-03-2013, 22:45
Well, Warp travel is highly unpredictable. In the wrong circumstances, you could arrive hundreds of years late, or, potentially, you could arrive before you departed.

jareddm3
15-03-2013, 22:56

From what I recall, it can take a matter of hours to days to reach the edge of a system, or at least far enough away from matter to keep from pulling it along with them once they enter the warp.

Lothlanathorian
15-03-2013, 23:02
Ah, derp. I misread what he was asking. I've read everything from a few days to a month traveling from the outer edges to a core planet in-system. I don't think it was specified how big these systems were or how far core-ward the destination planets were, though.

eutambem
15-03-2013, 23:16
i would say it would take from a few hours to about 2weeks at most.
first of all we need to remember that a ship comes out of the warp outside the system for safety reasons. we dont want to collide head on with a derelict asteroid or some moonlet that has gone out of orbit due to natural catastrophe.
second is the size of the system, that can have one planet or 2dozen of them (and wich will be the target of the travel). a good navigator can put a ship in the right trajectory to 'intercept' a planet in his orbit.
third, the gravity pull of the stellar objects may interfere with the approach.
at last take in account the sensor array of the ship itself to check on danger, the radiation emanating from the star, the sanity of the crew after such trip, and of course the xenos attacks because this is 40k!!!
i hope i helped. (i played a lot sci-fi roleplay back in the day...)

Hrw-Amen
16-03-2013, 17:04
Yes I would guess it depends on the size of the system and where you are heading inside it. It will also depend on the various sensors the ship has and how good the navigator is at plotting his / her way through the warp. Mostly I imagine them coming out of warp far enough out to have a reasonably good chance of not hitting anything too big that the shields could not bounce it off, but I do wonder on occasion if the mission requires it, say a space marine raid in a strike cruiser that needs the element of surprise? Is it ever possible to get the ship to drop from the warp right on top of a planet?Maybe risky, but if needs be, would they do it? If a defender has at least a couple of weeks notice of any potential attack they have loads of time to prepare fortifications around vital sites.

Francis
16-03-2013, 17:24
Is it ever possible to get the ship to drop from the warp right on top of a planet?Maybe risky, but if needs be, would they do it? If a defender has at least a couple of weeks notice of any potential attack they have loads of time to prepare fortifications around vital sites.

In several BL novels it is noted that chaos ships will enter or leave the warp very close to a planet if there is an emergency. I would also guess that an Imperial Captain could be tempted to do this if his ship was on its legs and the warp engines were still operational. I really can't see the navy do this a lot though. The space marines chapters and grey knights are a different story, with the best navigators in the galaxy and balls of steel I do think that it might be a valid tactic for Strike cruisers and battlebarges to use in a pinch.

Gaargod
16-03-2013, 17:41
Depends where they come out of the warp. Let's say they're acting in a solar system very similar to ours.

Do they need to come out of the warp outside of the Kuiper Belt, in order to avoid the most of the random debris. At its furthest point, it's about 50 AU from outside to the sun. So if they want to get to Earth, they need to travel about 49 AU. If they were travelling at light speed, that'd be about slightly less than 7 hours.
But, obviously, they won't be travelling at light speed. If they were only travelling at 1/4c (which is still mind bogglingly fast), it's going to take them a day to get from the outside to the Earth - and that's assuming the navigator gets the orbit perfect, so they come in on a direct line to where they want to be.

If they're going slower than that, which is highly likely (especially when you consider they probably have to accelerate a lot), and the system is bigger, which is entirely possible, you could be talking about weeks to get into the centre, even months.

However. Better ships (i.e. military ones, especially elite strike cruisers, etc) will likely be able to risk dropping much closer into the system. Their navigators will probably be better and their shields more capable of taking a hit. Plus, they'll likely have faster engines. This could cut the time down well into the hours, or even less - although the closer they get, the more risky it is. In an emergency, they might drop in very close indeed, but to do so probably risks the ship and everyone on it... so maybe not a good idea!

Hrw-Amen
16-03-2013, 21:05
Would it be more risky really though? If they dropped just outside the Kuiper Belt they would have to travel and navigate through it. They may run into things but I get the impression that even though there are probably millions of rocks there: 1. Most are very small. 2. Even though there are millions they are still thousands, if not millions of miles apart.

If they dropped in nearer to one of the main planets say Earth or Mars, by the era of W40k I would expect nearly if not all of the orbit crossing rocks would have been either mined away or moved and made into orbital docks or the like thus leaving the space around the planet clear for literally millions upon millions of miles, possibly just as clear if not more so than the outer reaches. as the large part of the orbit would be clear of stuff big enough to do any damage. I assume that they would not literally drop straight into orbit of course.

totgeboren
16-03-2013, 22:08
I thought the problem with especially dropping into the warp too close to big objects lead to the ship being ripped apart by gravitational forces? And something similar with dropping in close to planets and suns. Too close and your ship breaks from odd gravitational disturbances... not that they were really afraid of hitting some random debris (which could of course lead to catastrophic damage too).

Palvinore
16-03-2013, 22:08
Found the following quote from Andy Chambers from the BFG list of long ago:

I'm not sure if I've talked about scale before but here goes anyway. BFG works around an approximate scale of 1cm=1000KM for the planets and other tabletop features. Obviously this means the ship models are massively out of scale, an Imperial cruiser is NOT 9000KM+ long! The scale is basically there as a rule of thumb and I didn't worry about it too much when it came down to setting weapon ranges, ship speeds and so on. These were all done to create the right impression of distance on the tabletop. For example 60cm 'feels' like a long way and 30cm doesn't, the weapon ranges aren't defined by some pseudo-science calaculation of the energy dissipation rate of lasers (fairly obviously ) but to create an interaction between the (massively out of scale) models on the tabletop.

The more interesting question is perhaps how long is a turn, and that one I don't know the answer too - I'd guess somewhere between 15 minutes and an hour (quite likely telescoping so that at long range a turn is an hour but by the time you're within 15 cm its 15 minutes). This would make an attack craft capable of moving 30cm per ordnance phase capable of doing approximately 30-120,000 km/h. I've got no idea if this is realistic for starfighter speeds, or unfeasibly fast, incredibly slow or what , perhaps someone on the list could enlighten us all on this front (don't just tell us what it says it the Star Wars technical manual though!).

An Imperial cruiser moves at 20cm per turn. At 15 minutes per turn and 1,000km = 1 cm, then that is 80,000 km/hour. If on special orders of All Ahead Full, that is 44 cm or 176,000 km/hour absolute maximum. This creates problems though if you look at what is written in Rogue Trader RPG or elsewhere about travel times as at 176,000 km/hour it would take over 640 days to travel from Neptune orbit to Earth, assuming they were a straight line distance (making for 29.1 AU distance).

Kaldor Draigo
17-03-2013, 00:36
Well, I seem to remember the travel time from Mars to Earth given as less than 24 hours which, depending on the distance between the two planets at the time, would give you a travel speed of ~3,000,000 kph.

Now, obviously in space there is no air resistance or road friction, so pretty much all of your forward thrust translates into acceleration. This means that, theoretically, all ships will have a similar top speed. The only question is how quickly then can get there, and how well they can maneuver at those speeds. So rather than a question of speed, what's important is how fast a ship can accelerate.

Imperial ships seem to have a pretty well limitless power supply. Our current space craft can only carry a limited amount of fuel, so they need to carefully calculate when and where to fire rockets in order to accelerate and decelerate, or to change direction. 40K spacecraft no longer need to worry about things like that and can pretty much just burn their thrusters at full throttle for as long as they want, and then just burn their 'brakes' as hard as they want to slow down or change direction.

Now, the other consideration is that, while the ship might make a hard 90 degree turn at 3,000,000 kph, the people inside it won't. They'll splat into the wall across from them at a very terminal velocity. However this can be handwaved away with technology like inertial dampeners. If nothing else, they need some kind of fancy tech to make the gravity work on the ships!

So if a ship has no intention of slowing down to maneuver, it can probably travel very, very fast indeed. However if it expects, or wants to engage an enemy ship it likely must travel much more slowly, since the structural frame of the ship itself probably won't be able to cope with very quick changes in direction and momentum at high speeds. If it fired the 'brakes' at 3,000,000 kph for example, there's a good chance the entire ship would just concertina, like it had hit an immense brick wall. If you fired a directional rocket on the nose of the ship, to make it turn right for example, there's a good chance you'll just bend the ship in half or blow the front half of it clean off like a car getting it's nose clipped by a speeding train.

So in order to maneuver, even just to slow down, it's likely that any space ship would need to slow down considerably.

There was a scene in 'Flight of the Eisenstein' where the ship covers a distance noted as being 'several light minutes' in a scene that reads to be about ten minutes long. This would mean the Eisenstein covered about 1,000,000 kilometers in about ten minutes, or was traveling at about 6,000,000 kilometers an hour. The ship was also required to carry out evasive maneuvers during this scene, so we could possibly call it 'combat speed' although I think it would be the very top end of combat speed. All Ahead Full, in other words.

Phunting
17-03-2013, 02:08
There's obviously lots of problems with translating tabletop ranges to 'real' distances, however for what it's worth Rogue Trader puts 1VU at approximately 10,000k with ships moving between 3 and 10 VUs per turn for Imperial vessels. A turn is stated as half an hour, so a cruiser with an average speed of 5VUs would do about 100,000kph while frigates with an average speed of 8VUs do about 160,000 kph. This seems to roughly equate to the BFG rules as described above. Generally these vessels move at the speed of 'plot' however...

Hrw-Amen
17-03-2013, 19:21
I thought though that when they drop from the warp, are they not transitioning from faster than light to slower than light and the transition is the point at which they cross that threshold, albeit plotted and whatnot by the navigator. As such I would have thought a ship coming from the warp would be initially travelling at just under FTL and then the run into which ever planet it is going to is the time it takes to slow to a reasonable speed at which the ship can perform whatever maneuvers it wants to.

agurus1
18-03-2013, 00:30
I thought though that when they drop from the warp, are they not transitioning from faster than light to slower than light and the transition is the point at which they cross that threshold, albeit plotted and whatnot by the navigator. As such I would have thought a ship coming from the warp would be initially travelling at just under FTL and then the run into which ever planet it is going to is the time it takes to slow to a reasonable speed at which the ship can perform whatever maneuvers it wants to.

Generally from what I remember about reading in BL books about fleets arriving in system, this seems to be true. They have a fair amount of speed behind the coming out of warp, there doesn't seem to be a need to "accelerate".