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Old 10-21-2019, 05:53 PM   #21
Anthony
 
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by Daigoro View Post
You might have the command bridge with naval setting, so they can walk around and look out the front of the bridge (said gimballing optional). The problem with rocket-orientation is that you have to lie on your back to see where you're going- unless everything is done by instruments only.
  1. Everything is probably done by instrument anyway, instruments are more useful than vision for space maneuvering by TL 6 and for basically everything you might want to do in space by TL 8.
  2. There is no guarantee that the ship's nose is pointed in the direction it's traveling.
  3. There is no guarantee that the direction you want to look is towards the ship's nose. For realistic maneuvering it's far more likely to the direction the drives are pointed, as things like landings are done jets-first.
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Old 10-22-2019, 10:39 AM   #22
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by Daigoro View Post
With the gravity plates, gravity can be set arbitrarily, so there's no reason for it to be the same direction across the whole ship.
Well, that's the thing: I don't want completely arbitrary gravity, so I put some restrictions on the "disks". They must be round, and they apply their effect equally to both sides, pulling both sides towards their axis of rotation, or pushing them both away.

That said, if I have 1,000 engineers in a room figuring out how to lay this all out, it may be possible to get arbitrary gravity with those restrictions, but that's not the feel I want.

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The drive section at the rear might be rocket-down, so that equipment is attached to the thrust-down direction of the ship. A shell of gravity plates could be used to help lifting heavy equipment around.
Null gravity zones have turned out to be quite easy to do: you stick two disks both pulling towards each other and you get a nice pocket of null-G in-between them.

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Long axial corridors would be gravity radially down toward the ship's axis, as it would be a long dangerous fall with gravity axially down the corridor. Set strength to 0.2 G so that crew can quickly moon-hop along to their destinations.
Yeah, Major Passage ways are probably going to get their own gravity.

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I'm not sure how you'd handle transition sections between orthogonal G-zones, though they might be 0G for easy body rotation to orient to the G-vector for where you're headed.
0G zones between seem easiest, but thinking about how you get a crate on a pallet jack in and out might be the best method.

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The question is how big are the grav plates? How heavy? How much energy do they use? i.e. What are the economics of installing and running them? Can they be put anywhere and everywhere, or does their design limit how they can be used?
I haven't decided a minimum size. I do know I want them to have strong economies of scale, though I don't have the exact equation down yet. I want to discourage anything less than about 10 feet across, and strongly discourage anything less than 2 feet. The bigger, the better.

They produce a less efficient pull than a electromagnet of the same size, though range and substances pulled have different properties. They need to be very firmly secured: They are pulled or pushed by everything they pull or push, so they're major loads. I don't think I have a good idea of how much they're supposed to cost yet. I'd like a big industrial feel to them.

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And how switchable and responsive are they? If they're effectively instantaneous, then they can be basically inertial dampeners.
I've decided they will be fairly easy to tune their pull back and forth. Going from 0G to 1G probably takes about 5 seconds. You can even switch their direction, going from 1G to 0 to -1G. Each disk does have an optimum setting though, and you have to add extra (and expensive) reinforcement to both the disk and its mounting if you intend to reverse its pull.

So they will be able to act as inertial dampeners, but only if the acceleration is gradual enough, predictable enough, and oriented in the right direction. Its worth sticking in a dedicated disk system to cancel the engine though. humorously, I could see a pilot to be out of that cancelling effect so he can feel what the ship is doing.

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Originally Posted by Fred Brackin View Post
Try pouring hot coffee or going to the bathroom with that "5 degree slope" theory and you might not like the result. :)
I've been camping near crooked outhouses. Its not ideal, but its not that bad. If the ship is wobbling 5 degrees back and forth, that's another level of annoying, but nothing sailors haven't put up with for centuries. It would be nice to avoid it though.

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As for Dodging you don't do that with the main drive for big ships anyway. You can't turn the ship fast enough to bring main propulsion intot eh line you want. You have to use relatively large attitude thrusters that are scattered all over your hull.
That's not what spaceships would have you think (though that's hardly a final argument). Its not hard to imagine a ship where the potential acceleration from the attitude thrusters overshadows the more efficient but slower long-distance main engine. Where does gravity sit then? And is it a bad idea to position your main engine so that you have a "favored" attitude thruster?

OF course, by spaceship's rules, even dodging isn't likely to happen, given the accelerations, distances, and delta-v's I'm looking at using (Hot reaction drives, which just barely have the acceleration and delta-v to dodge for a few rounds of combat at long range 10 minute scale if you really build your ship for it).

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There is no gravity, so there is no "upwards". There is no atmosphere or ocean, so there is no "forwards". What direction you are going is a matter of "in what frame of reference?": in the ship's frame it isn't moving. Everything, including your destination and port of origin, is moving in all sorts of directions at speeds of several kilometres per second, while you are by definition stationary. The only direction that is significant is your thrust axis.
And the location of the enemy, who you will want to point things at and react to their counter-pointing.

Quote:
You might have the command bridge with naval setting, so they can walk around and look out the front of the bridge (said gimballing optional). The problem with rocket-orientation is that you have to lie on your back to see where you're going- unless everything is done by instruments only.
Quote:
Originally Posted by Anthony View Post
  1. Everything is probably done by instrument anyway, instruments are more useful than vision for space maneuvering by TL 6 and for basically everything you might want to do in space by TL 8.
  2. There is no guarantee that the ship's nose is pointed in the direction it's traveling.
  3. There is no guarantee that the direction you want to look is towards the ship's nose. For realistic maneuvering it's far more likely to the direction the drives are pointed, as things like landings are done jets-first.
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Originally Posted by Agemegos View Post
Everything probably is done by instruments only, as in the combat command centre of a modern warship.
I agree with the points favoring remote operation, but there are two caveats.

The first is that someone is going to disbelieve the instruments, his staff, and everything else, and demand to be able to take a look at what's going on out there, however illogical. The second is that this is a space opera ship, and sometimes they are depicted following out-dated schemes. I don't think I'm sticking the command center on the outside, but I'll probably have viewing stations of once sort or another.

And thanks for pointing out docking as a time when seeing where you are going is important. Its probably the only time human vision is actually useful. I don't know if the main drives are appropriate for that sort of manuever. Not the last few hundred yards, at least.
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Old 10-22-2019, 11:08 AM   #23
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by ericthered View Post
m.

I've been camping near crooked outhouses.
It's not the orientation of the floor that's in question. It's the net direction of gravity+acceleration and the way that affects liquids. Not the way it effects how the spacehands stand. The artifical gravity is only going in for human comfort (and possibly health). Making everyone apply a 5% "Kentucky windage" on all the hot coffee they pourfor soem reason I don't really understand is bizarre.

As for Spaceships and attitude thrusters, Spaceships is a simple, limited detail system for designing spaceships quickly. Attitude thrusters are one of those things that gets tossed into the mandatory "Control Room" which actually includes many things that aren't in the physical control room.

You'd have to go out of your way in Ve2 to include special extra engines for sideways thrust for dodging. At the ultra-realism level spitting out a hot reaction plume to your side while trying to change your motion would probably do more to tell your enemy where you actually are than the effect of changing your motion would disrupt his aim. Maybe you want to shut down your drives and use extra EW when you go into combat.

A question I have not heard answered yet about your artificial gravity discs is "What is their range?". Real gravity exerts a diminishing level of force over an unlimited range. Artifical gravity needs to exert a constant force over at least enough distance to go from floor to ceiling. Every inch farther than that is probably a disadvantage. If the artificial gravity has no range limits it's a very inconveniently infinte tractor beam rather than an artificial gravity system.
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Old 10-22-2019, 01:46 PM   #24
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by ericthered View Post
Null gravity zones have turned out to be quite easy to do: you stick two disks both pulling towards each other and you get a nice pocket of null-G in-between them.
As long as you're exactly equidistant between the disks? If you're slightly closer to one than the other, presumably you accelerate toward the close one. The zero-G spot isn't stable -- unless the force doesn't depend on distance from the disk. (Is that the case?)

You'd also need a sensors and a control feedback loop to balance the two disks.
(Yay, more things to break!) Or remarkably good quality control in manufacturing them.

Since we're talking military ships and damage control, accidental loss of one of the paired plates is likely. So the null-G zone probably isn't used for anything important or fundamental to ship operation. Maybe something like beds, or battery-powered disks you can slide under cargo pallets (and stick the sides as well).
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Old 10-22-2019, 02:07 PM   #25
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by Fred Brackin View Post
A question I have not heard answered yet about your artificial gravity discs is "What is their range?". Real gravity exerts a diminishing level of force over an unlimited range. Artifical gravity needs to exert a constant force over at least enough distance to go from floor to ceiling. Every inch farther than that is probably a disadvantage. If the artificial gravity has no range limits it's a very inconveniently infinte tractor beam rather than an artificial gravity system.
As a working concept, I have it exerting its full gravity from the base of the plate to a previously engineered height, at which location it rapidly tapers off.
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Old 10-22-2019, 02:12 PM   #26
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by ericthered View Post
Null gravity zones have turned out to be quite easy to do: you stick two disks both pulling towards each other and you get a nice pocket of null-G in-between them.
Wouldn't you also get 2G above and below them? And you'd get the disks pulling toward each other at 2G, which would be nasty for anything in the middle if their screws came loose. And... wouldn't they just cancel each other out, and still leave whatever stray gravity field lines you have lying about active? i.e. There'd be no useful effect on the target object, it'd still be subject to whatever forces are acting on it from the environment.

This is all unless the plates are also gravity-insulators, which in turn opens up a whole range of other issues.
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Old 10-22-2019, 02:19 PM   #27
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by ericthered View Post
As a working concept, I have it exerting its full gravity from the base of the plate to a previously engineered height, at which location it rapidly tapers off.
This result falls out naturally from the geometry, although that height depends on the diameter of the disk.

The inverse-square law holds when you consider a test mass at a distance from an object that you can treat as a point, as the field lines diverge spherically.

When your test mass is near a field-emitting plane, there is no field strength drop off w.r.t. distance as the field lines are all parallel, until you move far enough away from the plate for it to "look" like a point source.

Simple engineering tricks could be making the plate concave or convex (not sure which would get the desired result...) Otherwise, you can just handwave the attenuation distance.

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Originally Posted by Anaraxes View Post
As long as you're exactly equidistant between the disks? If you're slightly closer to one than the other, presumably you accelerate toward the close one. The zero-G spot isn't stable -- unless the force doesn't depend on distance from the disk. (Is that the case?)
Where the field lines are parallel between the disks, opposing forces would cancel out equally at all points between them. But you're right in them having to be perfectly aligned.
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Old 10-22-2019, 03:08 PM   #28
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by ericthered View Post
As a working concept, I have it exerting its full gravity from the base of the plate to a previously engineered height, at which location it rapidly tapers off.
The simple version is that you need to have two plates (one attractive, one repulsive) and it applies in the region between the plates.
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Old 10-22-2019, 04:47 PM   #29
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Default Re: Spaceship Weapons and Gravity Layout

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The simple version is that you need to have two plates (one attractive, one repulsive) and it applies in the region between the plates.
I considered that model of artificial gravity, and ultimately I decided against it. It probably does make things simpler.

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Originally Posted by Daigoro View Post
Wouldn't you also get 2G above and below them? And you'd get the disks pulling toward each other at 2G, which would be nasty for anything in the middle if their screws came loose. And... wouldn't they just cancel each other out, and still leave whatever stray gravity field lines you have lying about active? i.e. There'd be no useful effect on the target object, it'd still be subject to whatever forces are acting on it from the environment.
Yes, you've read that correctly. You get a null zone between them that's still effected by external forces, they are pulling on each other, and if you get your overlaps wrong you're got 2G on the far sides of the plates. I would not plan on securing these things with mere screws, regardless of if they're facing each other or not. I think the one thing you might be missing is that the height or the field is not related to the height of the disk.

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Originally Posted by Daigoro View Post
This result falls out naturally from the geometry, although that height depends on the diameter of the disk.

The inverse-square law holds when you consider a test mass at a distance from an object that you can treat as a point, as the field lines diverge spherically.

When your test mass is near a field-emitting plane, there is no field strength drop off w.r.t. distance as the field lines are all parallel, until you move far enough away from the plate for it to "look" like a point source.

Simple engineering tricks could be making the plate concave or convex (not sure which would get the desired result...) Otherwise, you can just handwave the attenuation distance.
Oh wow, I'd forgotten about that particular geometric quirk of gravity. That's intriguing. I wonder what the natural height of the effect from a disk is? I'm a touch worried the effect will be small compared to the radius of the disk. I don't have to use this, but its a nice piece of math to think about and play with.

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Originally Posted by Fred Brackin View Post
It's not the orientation of the floor that's in question. It's the net direction of gravity+acceleration and the way that affects liquids. Not the way it effects how the spacehands stand. The artifical gravity is only going in for human comfort (and possibly health). Making everyone apply a 5% "Kentucky windage" on all the hot coffee they pourfor soem reason I don't really understand is bizarre.
Gravity and Constant acceleration are indistinguishable from each other in a closed system. I usually see that statement made right before people talk about general relativity and gravity. I will grant that if the acceleration is from spinning you can get some fun effects, and if the acceleration is changing that can really cramp your style.

At this point, I think I'm either lining up gravity with the main acceleration, minimizing how often those main engines fire, or using a disk to apply a neutralizing effect.

Quote:
As for Spaceships and attitude thrusters, Spaceships is a simple, limited detail system for designing spaceships quickly. Attitude thrusters are one of those things that gets tossed into the mandatory "Control Room" which actually includes many things that aren't in the physical control room.
I know where attitude thrusters come from. I'm just saying the spaceships requires you to be burning fuel with your main engine to be allowed to dodge in spaceships combat. Attitude thrusters presumably don't match your main engine. But as we both said, its a simple system to get the game going, so its not hugely important.

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You'd have to go out of your way in Ve2 to include special extra engines for sideways thrust for dodging. At the ultra-realism level spitting out a hot reaction plume to your side while trying to change your motion would probably do more to tell your enemy where you actually are than the effect of changing your motion would disrupt his aim. Maybe you want to shut down your drives and use extra EW when you go into combat.
That's not a bad point. The reaction plume is likely to be among the most visible parts of your ship. I suppose it depends on how tight the loop between their telescopes, computers, and gunnery corrections are. If they've got telescopes that can quickly determine how much plume you just shot out, and in precisely what direction, and the organizational and computing power to feed the guns updated estimates of where you're going, it reduces the utility of dodging a lot. But if any one of those fails, its effective if expensive dodging.

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Originally Posted by Anaraxes View Post
As long as you're exactly equidistant between the disks? If you're slightly closer to one than the other, presumably you accelerate toward the close one. The zero-G spot isn't stable -- unless the force doesn't depend on distance from the disk. (Is that the case?)
Yes, the disks have a set distance at which they apply uniform gravity. Though Diagro has me thinking about that.
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Old 10-22-2019, 09:48 PM   #30
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Default Re: Spaceship Weapons and Gravity Layout

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Originally Posted by Anthony View Post
The simple version is that you need to have two plates (one attractive, one repulsive) and it applies in the region between the plates.
That's the way I'd make it work. In fact I'd have the floor plate produce a .25 G attractive force for a distance of 1.2 meters by itself and the ceiling do .25G of repulsion with the same sort of range. Run them both at the same time and synergy of the pseudo-particles involved gives you 1.0 Gs over 2.4 meters.

Makign things relatively weak like this can serve to ewduce at least some of the abuses possible with such pseudo-particles.
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