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Old 01-09-2009, 05:25 PM   #11
DungeonCrawler
 
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

Quote:
Originally Posted by Langy
Why? How do reactionless thrusters or high delta-v fuels make space fighters more useful?
Quote:
Originally Posted by SuedodeuS
I think the concept here is, if the fighter is going to be maneuvering a great deal in the fight (necessary if it's trying to capitalize on its increased maneuverability), it's going to be changing its velocity a lot, which means it's going to burn through a lot of delta-v. In order to not have to sacrifice a good deal of space for fuel tanks, either high delta-v fuels or reactionless engines are going to be necessary.
Exactly.

By themselves, those things may not make space fighters useful, but without them space fighters are pretty much impossible. Even if one or two-man craft existed, they'd no longer be "space fighters".
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Old 01-09-2009, 05:28 PM   #12
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

Space fighters don't have to be characterized by exceptionally high acceleration, unless a narrow definition is used. They do need to be able to attain tactical maneuvering thrust, in general, but not necessarily more than that.

Small fighters require carriers, and thus capital ships, to exist. If heavier SM+6 fighters are the norm and reactionless drives are used you might be able to do without large units altogether, but they'll probably exist anyway for transport. Carrier fighters also will be stronger than long-range fighters, even in a reactionless regime, because they don't need endurance features. Below TL10, this also can save you a lot of money by using chemical power rather than costly reactors. This is assuming that space remains big. If 24 hours is plenty of time to get wherever you might want to go, carriers become somewhat unnecessary.

These provide a target. That's important, since deep-space fighters probably aren't going to be very good at attacking planetary targets, except under extreme space-opera regemes.

Small craft are fundamentally advantaged against capital warships by their size and partitioning. Against heavy weapons (which notably includes all the longest-ranged weapons) they take preposterously low losses compared to a larger warship. It helps them a lot if gunnery skills can be assumed to fall within human norms, because they get much more out of the miss rate than a larger unit.

So attack craft should be viable if the balance of weapons and armor makes a compact weapon system operating inside the enemy's field of fire useful, and especially if the anti-capital weapon has more range than effective anti-fighter weapons.

Attack craft aren't exactly fighters though. They're defined by a weapon that makes big ships afraid of them, which may not be ideal for hitting other small units. (Though it may...if my reading is correct it's hard to beat the by-the-book 16cm missile for just about any role.) If they mix anti-capital and anti-small craft weapons, they might qualify as multi-role fighters.

A true fighter would be an interceptor designed to kill attack craft, or kill fighters threatening attack craft. It seems like their basic requirement is to be more capable in that role than capital-ship defensive batteries.


Space fighters will not fight like air fighters. That's practically impossible to justify low relative speed maneuvers in open space without some kind of Star Wars type wholesale abandonment of Newtonian mechanics. But combat passes don't seem to me to preclude the 'fighterness' of a small craft that shoots other small craft.

Last edited by Ulzgoroth; 01-09-2009 at 05:32 PM.
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Old 01-09-2009, 05:37 PM   #13
Anthony
 
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

The main reason why reactionless drives are more favorable to space fighters is the fact that a missile just needs to go one way, and thus requires a delta-V of X. A fighter needs to, after getting to the target, stop, and then return home. This requires a total delta-V of somewhat more than 2X.

With conventional reaction drives, a missile might already have a 50% fuel fraction, which means a fighter winds up needing a 75% fuel fraction, which is a big hit on its effectiveness. However, if you have a drive that uses small amounts of fuel, the difference between 5% fuel and 10% fuel is not that crippling.

Another way to handle this is if a 'fighter' is really just a transport for expendable munitions. If we assume a full missile is 10% operations, 40% payload, 50% fuel, you can do the round trip with a fighter that's 10% operations, 30% payload, 60% fuel, because it only needs enough fuel to get the 10% home. With constant-power variable-ISp drives (such as VASIMR) it becomes even easier, because you can run the drive in low gear on the way out, high gear on the way back (since you're not moving as much mass as before, you still have about the same acceleration); something like 10% operations, 38% payload, 52% fuel is adequate.
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Old 01-09-2009, 05:40 PM   #14
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

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Originally Posted by Ulzgoroth
A true fighter would be an interceptor designed to kill attack craft, or kill fighters threatening attack craft. It seems like their basic requirement is to be more capable in that role than capital-ship defensive batteries.
QFT.

Dropping the effectiveness of beam weapons in an anti-fighter role is probably the best option to get here. The low sAcc of guns and the low RoF of missiles - combined with the fact that a large ship is going to have difficulty matching velocities (good for getting rid of the relative velocity penalty) with attacking fighters - means that interceptors with VRF guns are probably going to be the best defense against small craft.
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Old 01-09-2009, 05:44 PM   #15
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

High delta-v fuels are only needed for a short time in combat, though.

Say you've got a 3-minute turn in a standard-scale encounter. You need 1G and 1 mps of delta-v per +2 acceleration bonus. There's no other use for delta-v in the space combat under the Spaceships system that I can see. That makes a ship that has, say, 30 delta-v total have more than enough DV for an entire combat encounter. Mind you, that's a lot for most drives - but not too much for a nuclear pulse drive, for example.
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Old 01-09-2009, 05:45 PM   #16
David Johnston2
 
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

[QUOTE=Molokh]
Quote:
Greetings, all!

Inspired, by two other current threads (one very close, the other only vaguely related), I wanted to fine-tune the question:

Under what tech assumptions are Space Fighters actually useful? Nonexistent AI seems like an early prerequisite.
Not really. If you look in Spaceships, it seems to be pretty irrelevant to cost and performance whether the intelligence in the control room is organic or not and a human military is going to want a human in the command loop to authorize any firing of weapons. Unless AIs are fully integrated into society as citizens, people aren't going to be willing to hand over the decision to kill or not to them. Even then, you have to ask yourself whether the human pilots might be cheaper than an AI control system of similar capability.

Of course an AI piloted fighter is still a fighter. The big issue is whether small vessels themselves are going to be effective tools of war. Assuming that you haven't nerfed missiles though, the real question may very well be whether large vessels are effective tools of war. Small expendable firing platforms operating off mother ships might be just the thing for space warfare.
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Old 01-09-2009, 05:47 PM   #17
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

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Originally Posted by Molokh
Greetings, all!

Yes, I know under most assumptions they're useless - I always proposes to replace them with AKVs if they sound better. But it's not about proving them useless. I'm sure most of you know what the topic is about.
The major one is going to be scale limited technologies. A drive that is faster for smaller ships than larger ones, or simply not practical for larger ships at all, is largely what naval aviation has going for it now. But there are other possibilities - a maximum size of force screens for example.

One hit, one kill weapons help too, in the sense that while it might not favor fighters, it keeps down the maximum size of ships enough that the gap between a fighter and a serious capital ship is smaller. We see some of that in navies now, and I'm sure we'd see a lot more if there were more risk of naval engagements involving a nuclear exchange. These aren't so great for a game though, since "you're hit, your character dies" isn't real good in an RPG, and "you see the enemy first, you win" kind of kills the turn structure and maneuver phase for a wargame.
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Old 01-09-2009, 06:03 PM   #18
dynaman
 
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

Space fighters will be useful under the following conditions.

First, AI has to be low, or there has to be a reason why it is not better to use a robotic fighter. This is pretty much required.

With that out of the way, if there are highly damaging weapons per weight then fighters will be the primary combat weapon. No use sending out a large ship when a fighter can take it out...

Another possability is scouting, large ships are still expensive and smaller ones are better at looking for the enemy (or verifying the enemy is where you think they are).

Third would be if resupply is needed, small fighters can take out supply ships (even if they can't get through the shields of a warship).

Fourth is if ships have exposed sensors, fighter can go in first to blind the enemy making is easier for your capital ships to finish them off.
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Old 01-09-2009, 07:44 PM   #19
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

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Originally Posted by DungeonCrawler
I've got no clue what an AKV is,

(SNIP)
Autonomous Kill Vehicle. An armed drone piloted by an on-board sapient artificial intelligence (SAI). The SAI does not require a life-support system -- just enough electricity to keep the computer running. It's also immune to g-forces, which gives it superior maneuverability. Finally, you make a back-up copy of the SAI just before it launches, so it's fairly fearless -- especially if it's programmed that way, in the first place.

The idea originated in the Transhuman Space Line.
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Old 01-09-2009, 07:55 PM   #20
David Johnston2
 
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Default Re: [Spaceships] Under what tech assumptions Space Fighters make sense?

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Originally Posted by tshiggins
Autonomous Kill Vehicle. An armed drone piloted by an on-board sapient artificial intelligence (SAI). The SAI does not require a life-support system --
The fighter doesn't require a life-support system either. You are going to be wearing a space-suit, after all. And frankly, everything I've done with space vehicle design suggests to me that it's unlikely that you'll end up pulling more Gs than a human can take.

Last edited by David Johnston2; 01-09-2009 at 08:19 PM.
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