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Post by CELS on Jun 29, 2004 4:50:28 GMT -5
First off, Vatsy, there's no need to quote my entire post. If people wanted to read my post, they could just read the one above yours Press reply if you want to reply without quoting. Press quote if you plan to reply to specific parts of my post. Don't just quote the entire post, since there isn't really any point in that. That said, I'm well aware of the design considerations you mention, but I don't know how to use this to make sense of different hull designs in 40k. The spreadsheet you offer allows me to make calculations, but that's not what I need. I need help to figure out why ships in 40k vary in shape. Why are some 'needle' shaped and other 'box' shaped? As you can see in my post, my argument is that all transport ships should be compact, to improve acceleration and maneuverability. I do not see the point of having needle shaped super-heavy barges. They would just be tremendously slow to accelerate and difficult to turn. Your spreadsheet doesn't explain the point with a needle-shaped ship. That's why I'm asking. Why do Imperial transports and heavy transports have the same shape as Imperial warships? The functions of most transport ships would be pretty similar. Most should be capable of picking up containers (probably more or less cube-shaped), carrying them either internally or externally, and quickly unloading them at their destination. Some transports may rely on ship-to-ship cargo transfer, as the cargo doesn't come in containers. This would be true for most livestock-transports and passenger transports, I suppose, as well as the most luxurious sprint traders, perhaps. At this point, I'm only interested in ships capable of warp travel. The purpose should be fairly obvious. We're talking about transports. Atmospheric capable? Some ships might be, but now I'm mainly concerned with bulk freighters, sprint traders, super-heavy barges, etc.
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Post by Sojourner on Jun 29, 2004 5:14:39 GMT -5
Why?
Straight-line thrust is not affected at all by the shape of whatever it's pushing, and turning would probably be improved if anything, by virtue of force-magnifcation by turning moments (that is, mounting maneuvering thrusters far away from the centre of mass)
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Post by Kage2020 on Jun 29, 2004 6:05:07 GMT -5
Really do wish this had the simpler to use Portent/Critical Hit quotation system. Would be far easier. Apologies for old-style Portent posting! And one can hope that the reason can be seen... Function, origin... aesthetics. The normal, as you subsequently say. Extending pure naval analogies to a space-borne fleet might be problematic, but it is what is done in 40k and, indeed, even looking through the 'ole MT Fighting Ships of the Imperium the influence of modern navy can be seen... Of course, that's more a product of influence on modern artists, but there we go. And interstellar debris, including glance. 'Streamlined' hulls increase the chance of a glancing blow for low-velocity particles. High velocity ones, of course, are more likely just to go right through... Erm... yes, but that's not really something that you would generally consider doing. Remembering that you're not exactly throwing planets at the beggers. The sheer size of Imperial ships should allow reasonable 'targetting' anyway, so the relative advantage of 'long sleek' ships vs. 'big cubes' is tempered by such a consideration. A reasonable point, though tacitly assuming a lack of guidance electronics even if said 'electronics' is a servitor slaved in the nose cone of a torpedo! Erm... It does? The "Rule of the Cool" does that more than well enough as it is. That and, simply, design momentum, i.e. the idea that one tends to stick to pre-established ideas. See "Rule of Cool", I'm afraid. It's the easiest answer. The 'warp field' idea is very Star Trek, but that doesn't make it necessarily inappropriate. See Sojourner's comments, below. Furthermore, transport ships do not need fast accelerations, 'small turning arcs', or whatever. They are not warships.
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Post by CELS on Jun 29, 2004 6:31:11 GMT -5
Straight-line thrust is not affected by the shape of whatever it's pushing? Boy, sometimes I wish I'd studied physics... So if you have a huge dish the size of a football stadium in space, and you put a huge rocket-engine in the center, that doesn't put enormous strain on the dish? Because in an atmosphere, of course, the resistance would probably cause the rocket-engine to break through the dish...
And then, what about GW's argument about Imperial warships being unable to stop on a dime because it would cause great damage to the ship? Hogwash?
Well, if we're operating with the 'rule of cool' here, I'll just post my list and be done with this. People seem unwilling to discuss this subject, so I guess we should just guestimate some numbers and be done with it.
Super-heavy barge: x * x * 8x - x * x * 10x Heavy barge: x * 2x * 7x - x * 2x * 10 x Barge: x * x * 6x - x * x * 8x Carrack - x * 2x * 5x - x * x * 7x Galleon - x * 2x * 5x - x * x * 7x Freighter - x * x * 5x - x * x * 6x Clipper - x * x * 5x - x * x * 7x Sprint trader - 2x * 3x * 9x - x * x * 10x Caravel - x * 2x * 4x - x * 2x * 5x
Now we just need volume estimates, and we've got the hierarchy.
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Post by Sojourner on Jun 29, 2004 7:27:39 GMT -5
Starships don't fly in atmosphere...
If you're bending the dish, yes, it does. But you're not bending the ship superstructure, you're compressing it. Metals, which ship superstructures are made of, are *extremely* strong in compression. You run into problems with deceleration if, that's if the retro engines are mounted near the rear, and thus having a pull on the centre of mass, thus subjecting the superstructure to tensile stress, which probably will cause damage to an extremely large structure.
As for turning, GW are fudging this a bit. All you need is a suitable arrangement of maneuvering thrusters, and a properly designed superstructure to avoid damaging the vessel.
And finally - I understand that some people have been a bit miffed about my bluntness when scientific debate occurs. Who's being blunt now?
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Post by CELS on Jun 29, 2004 8:30:28 GMT -5
Starships don't fly in atmosphere... Erm, yes, I know. I was just saying, in an atmosphere, that kind of thing would go wrong, so I figured it might be similar in space. And before someone is kind enough to point this out- yes, I know there's no air in space Then couldn't the same happen if you a have a very broad ship with engines only in the middle? Wouldn't the same forces that might bend the dish damage this ship? But otherwise, you should be fine? Good, I'll take your word for it. I didn't study physics, unfortunately. Am I being blunt? How so?
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Post by Sojourner on Jun 29, 2004 9:25:39 GMT -5
The 'hogwash' bit was what grated with me. Perhaps I misinterpreted that, I assumed you were siding with them when now perhaps what you meant was that it actually is?
Basically what I'm getting at with all this is that the only important factor is where the centre of mass is with relation to the force applied. Pushing the structure together isn't a problem, as it's made of metal and metal has no problems with compression. Pulling and shearing it are different problems. It's complicated to explain, better to consider in terms of specific problems.
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Post by CELS on Jun 29, 2004 11:42:48 GMT -5
The 'hogwash' bit was what grated with me. Perhaps I misinterpreted that, I assumed you were siding with them when now perhaps what you meant was that it actually is? Ah, yes, you misinterpreted that. Perhaps I should have thrown in a smiley there... Actually, I'm fully prepared to accept official fluff as hogwash, especially justification for BFG rules, since they are based more on 16th century naval warfare than science fiction! Ah well. As long as everyone's happy with the shapes I have suggested for the different ship types, I'm happy.
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Post by Minister on Jul 9, 2004 2:58:18 GMT -5
True, but it's a fun kind of hogwash, and I like BFG better than Full Thrust as a game.
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Post by CELS on Jul 9, 2004 4:21:47 GMT -5
Well, this is kinda Off T, but I think the game is great fun as well. A great strategical challenge even in smaller games, and the rules are simple. Sure you could use rules that would make it more 3d, but it's fun now, and 40k was never meant to be realistic anyway Now... perhaps someone could help me with a suggestion for volume for the different ship types (battleship, grand cruiser, barge, galleon, etc) so we can post a finished hierarchy, complete with length estimates and everything?
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Post by Kage2020 on Jul 11, 2004 1:46:22 GMT -5
Is that hierarchy purely a volume one, or are we talking about something which integrates with function? And since you posted the volume calculations, do you have a preference with regards to any one dimension? We could then use this the other way around, i.e. length determining volume and therefore adhering more to the 'fluff' than preference?
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Post by CELS on Jul 11, 2004 2:56:00 GMT -5
Is that hierarchy purely a volume one, or are we talking about something which integrates with function? Mostly volume, but there are function considerations. A sprint trader is obviously designed for speed, and whilst it might be the same size as a clipper, it's drastically different in design. Other than that, the function of the ship is determined mostly by the sub-category, such as 'bulk', or 'passenger'. So you could have a passenger clipper or a bulk freighter. This hierarchy is based on volume, however. Good point. Well... the smallest warp capable ship should be around the same size of an Imperial destroyer, so maybe 250-300 meters as a minimum. A standard Imperial line cruiser is, what, 1400 meters? That should be approximately the same length as a barge. A super-heavy barge should be somewhere along the lines of a battleship. I don't remember how long we decided a battleship would be... must check out the flagship thread. Edit; 4600 meters... oh boy.. well, that would be the length of an average super-heavy barge.
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Post by Kage2020 on Jul 11, 2004 3:19:55 GMT -5
Good point. Well... the smallest warp capable ship should be around the same size of an Imperial destroyer, so maybe 250-300 meters as a minimum. <grin> We've already determines that the smallest warp-capable ship is around 135m in length, v-displacing some 3,000 tons. Importantly this was considered the minimim economically feasible size for a warp-capable ship, not technically the smallest that they could make. (Cf. Inquisitorial 'psi-sensor' ships taken into the Eye of Terror.) Edit; 4600 meters... oh boy.. well, that would be the length of an average super-heavy barge. Oooh... means that 2,100,000 v-displacement tons is too small for a battleship/dreadnought... Then again it was suggested using a "needle ship" configuration, which is not wholly appropriate to Imperial battleships. (Well, except the Gothic.) I don't suppose you could append suggested lengths based on the BFG models to those fomulae? Then it would be a simple matter of just calculating a rough estimate of the volume and using that as a guide to producing a framework suggestion... In fact, doing it for known military ships would also be useful so that we don't get into the problem that happened with the "Retribution"...
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Post by ErnestBorgnine on Jul 14, 2004 8:06:28 GMT -5
As for turning, GW are fudging this a bit. All you need is a suitable arrangement of maneuvering thrusters, and a properly designed superstructure to avoid damaging the vessel. True, that's all you need to turn it and if it can stand the compression of the main drive I can't believe the superstructure wouldn't stand up to maneuvering thrusters, but still, wouldn't conservation of angular momentum suggest a long tube shape is going to be a PITA to turn compared to, say, a Kroot warsphere?
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Post by Minister on Jul 14, 2004 8:17:26 GMT -5
Reguarding volumes... you have been reading my design thread posts with the stupidly long calculations, havn't you?
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