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Re: Miniatures combat

Posted: Wed Mar 11, 2009 10:04 pm
by SciFiGuy
My normal weapons range is less than a half light second - (150,000 km). That way, targeting data can be acquired in "real time" (well, less than a second) and it's a bit easier on the brain.
Missiles could have a range greater than a half-light-second, as they can correct their course. The AI package in missiles try to match the same course as their target. Once it's on the same bearing, it can stop thrusting and save fuel. The mass-to-thrust ratio greatly favours missiles, so they should be able to overtake their target (relatively) quickly. Coasting lets them save their fuel for minor course corrections, and for the 'terminal guidance' phase. Plus, the ship being pursued won't know if the missile has exhausted its fuel or if it's just coasting (unless it changes course to see if the missile does the same).

The AI is also smart enough so that it won't coast if the range exceeds a certain distance.

In practise, most missiles miss their target or run out of fuel. But they are useful for making the enemy waste fuel by changing their course frequently (which slows them down. To significantly alter their heading, they have to apply a delta v 90-degrees to their current heading to make an appreciable course correction). If they go too fast, they may not be able to turn very quickly.

So, if my Vector is 000°|10,000KM (i.e. each 'turn' their ship travels 10,000 km in the direction of 000°). If they want to change to 315°, they'd have to apply a sidewards thrust (pointing to 270°) equal to their main engine thrust of 10,000km. Since the thrust is the same, the vector addition gives you a heading of 315° for the next turn. Ideally, the ship should cut thrust, rotate 90° starboard, then resume full thrust. If they've been accellerating for more than a single turn, they'd have a curving/arcing course until the vectors 'evened out' and they were pointing the direction they wanted to be facing.

Of course, if the target ship is having to evade dozens of missiles, it's chances for successfully evading them all starts to diminish.

Smaller ships (in my setting) have been known to have 'throw-away' missile launchers attached to their hull during refueling or minor repairs. That way when it's ID'd by a hostile ship, they (may) not know about it's missiles and not factor them into their attack strategy. While long rage, if you fired one at very close ranges, the odds of a hit greatly go up.

I have a spreadsheet that factors in a ship's hull size (in cubic meters) and it generates percentage chances of a To Hit. In a hard science fiction setting, Detection is almost automatic. Ships radiate heat and heat travels at the speed of light (it's just Infared light). So, as long as you can scan space with a very basic IR sensor, then you'll pick up a starship. And when it fires its engines, you get a spectrascopic reading on the tail flame and that tells you how hot it's burning. Compare that to how fast the ship changed speed, and you have it's Mass. That's all 100% science up to this point. Once you have the mass, you can compare it to Ship Classes in your game. "That ship's massing a million metric tons. Gotta be their new Avenger-class Destroyer. Charge the rail guns..."

Re: Miniatures combat

Posted: Wed Mar 11, 2009 11:54 pm
by neutral stalker
you have a lot of time to think about this, dont you?

railguns are awesome. woo magnetic accelerator cannons :)

Re: Miniatures combat

Posted: Thu Mar 12, 2009 5:04 pm
by SciFiGuy
neutral stalker wrote:you have a lot of time to think about this, dont you?

railguns are awesome. woo magnetic accelerator cannons :)

Well, I've been working on it off and on for a few years.
I don't have a lot of free time, but I do enjoy this sort of stuff.

On a side note, the railgun round that is shot out comes out cherry red hot.
The ammo is causing a hard short between two highly-charged rails, so a by-product is that each round is a 'hot shot' round (using Golden Age of Sailing terms).

Unfortunately, that means the railgun rounds would show up on passive IR sensors.

In Ye Olde Days, some Captains would get a fire going in a container on their decks and put cannon balls in it.
When they were glowing red hot, they'd (carefully) transfer them to the cannons.
When the Hot Shot hit a sail or their wooden decks, they usually caused a fire.
Unfortunately, the heating container would often get tossed around and end up setting their own ship ablaze.

Hot Shot were more common on Forts - someplace with stone, rather than wood.

A popular choice of ammo for Railguns is DU (Depleted Uranium). Besides being incredibly dense, one of the properties of DU is that it's Self-Sharpening.
That is to say, when a bit of it gets rubbed off or flakes off (when it impacts something hard), the central core of the DU slug actually flakes or sheds its bits so that the point stays nice and sharp.
A small DU round, given sufficient accelleration, should easily penetrate thick armour.

You could even use Californium Rounds - radioactive material that has a 25%-50% chance of causing a micro-nuclear explosion under the right conditions.
Perhaps a DU layer, wrapped around a core of Californium.
A Tactial Nuclear explosion in your Bridge would tend to ruin your day...

Re: Miniatures combat

Posted: Fri Mar 13, 2009 12:00 am
by neutral stalker
the railgun variant that ive studied personally consists of a titanium core held in place by steel sleeves. a multi stage magnetic coil pulls and pushes the outer sleeve forward at incredible speed. after exiting the barrel, the sleeve breaks away and you have a nice big titanium spear poking through you. the steel shell is retreived and used again.

Re: Miniatures combat

Posted: Sat Mar 14, 2009 3:20 pm
by SciFiGuy

It sounds like you are describing a COILGUN, not a RAILGUN.

Here's a snippet from Wikipedia:
A railgun is a purely electrical gun that accelerates a conductive projectile along a pair of metal rails using the same principles as the homopolar motor.

Railguns use two sliding or rolling contacts[1] that permit a large electric current to pass through the projectile. This current interacts with the strong magnetic fields generated by the rails and this accelerates the projectile.

The U.S. Navy has tested a railgun that accelerates a 7 pound projectile to seven times the speed of sound.[2]

Railguns should not be confused with:

* Coilguns (Gauss guns), which are contactless and use a magnetic field generated by external coils arranged along the barrel to accelerate a magnetic projectile.
* Railway guns, which are very large artillery pieces placed on railway tracks and predominantly used in and between the American civil war and the Second World War.

Here's a snippet about the negative aspects of COILGUNS:
Projectile saturation
One of the greatest limitations to the coil gun is the rate at which the ferromagnetic projectile becomes fully saturated by the magnetic field and the rate at which it loses its magnetic saturation. Once a ferromagnetic object becomes completely saturated the amount of force in which it can be attracted stops increasing. The rate at which the projectile loses its saturation is critical; as this rate is constant, greater distances between drive electromagnets are needed to compensate for this rate. As the projectile increases in speed it reaches drive electromagnets at progressively faster rates. Without compensation for desaturation time, there will be less and less effect to the velocity of the projectile, resulting in significantly lower efficiency per drive electromagnet stage as the projectile travels down the line. Once the amount of force exerted to the projectile is less than or equal to the amount of resistance exerted on the projectile due to air friction and friction in the barrel the projectile will no longer gain velocity. Projectile saturation can be treated by either using a different metal that has a higher saturation point, or increasing the mass of the projectile. Usually when a saturation point of a metal goes up, its permeability goes down. This reduces the force on the projectile.

Re: Miniatures combat

Posted: Sun Mar 15, 2009 4:10 am
by neutral stalker
oh. i stand corrected.

thanks for clarifying.

by any chance did you read my post on shield technology in the "discuss the latest page" topic?

Re: Miniatures combat

Posted: Tue Mar 17, 2009 9:20 am
by kirkspencer
If I may suggest another engine, see Attack Vector:Tactical from Hard science based, plus it lets you handle 3d newtonian movement easily. (How easily, you ask?) Well, easily enough I've taught ten-year-olds to play. Not well (they don't get tactics), but the mechanics are handled.

Yes, 3D makes a difference.

Re: Miniatures combat

Posted: Wed Mar 18, 2009 9:29 pm
by SciFiGuy
ah yeah - I've heard good things about that system.
I think you get to ignore any one of the three Newton's Laws - kinda interesting take on it.
The only way I can imagine the miniatures would be on sticks, like I remember seeing the WW2 / Vietnam fighter jet gamers from waaaaaaaaaay back when.
Not sure if I want to break the 3D barrier or not.

Re: Miniatures combat

Posted: Fri Mar 20, 2009 9:53 pm
by Froggy the Great
Wow, this has been an amusing discussion to walk, especially as the game I first suggested is one of the more simplistic fighter-plane games I know.
For the record, Full Thrust is my large-ship game of choice, and I was going to make a CD-themed fleet or two back in the day, but I didn't.

Re: Miniatures combat

Posted: Wed Sep 30, 2009 11:02 am
by neutral stalker
ummmm any of you play warhammer?