Star Destroyers' Garbage

[Treknobabble]

Canon alone gives us MT level firepower for 'light' turbolasers. I give you ESB and the asteroid field sequence...

4 megatons for the light turbolasers (based on the scene where the falcon gets jostled by a turbolaser hit). Based on Wong's scaling estimate, that gives you maybe 500 megatons for the big guns. If we instead go with an analogy between the yield of a surface-to-air missile (usually carries 50-150 kg of high explosives) and the yield of a surface-to-surface missile (usually carries 200-1000 kg of high explosive), that estimate gets reduced to around 80 megatons for the big guns. All well within standard sci-fi fare.

Ignoring the complete irrelevancy of that comparison,

No, let's not ignore the relevance, because I'm prepared to defend it. A modern ship will carry surface-to-surface missiles to deal with big targets (other ships) and surface-to-air missiles to deal with small ones (aircraft). The ISD carries heavy turbolasers to deal with other capital ships and light turbolasers to deal with smaler ones. The analogy seems pretty exact, and is just as likely to give a sense of the difference in firepower as a volumetric comparison, if not more likely.

that gets you...80MT for a HTL for DEW...against ships that die to single figure MT omnidirectional explosions. My money is sure as hell not on the B5 side.

Um, yeah, no. A pair of single figure MT proximity detonations killed a Sharlin (the best the Younger Races had to offer) and 500MT omnidirectional explosives could take out Shadow and Vorlon vessels. A 200 MW pulse cannon was apparently a credible threat to YR freighters.

But we're only going to have a handful of imperial vessels here.

Every single one of which can ignore any reasonable amount of YR ships with impunity.

Assuming we get a ten to one advantage with the YR ships, the required firepower advantage an ISD would need to have over a YR ship in order to win would be a hundred to one. Our calculations indicate a firepower disparity closer to 10:1.

An N-fold increase in quantity is as valuable as an N-squared-fold increase in quality.

[Eternal_Freedom]

4 megatons for the light turbolasers (based on the scene where the falcon gets jostled by a turbolaser hit). Based on Wong's scaling estimate, that gives you maybe 500 megatons for the big guns. If we instead go with an analogy between the yield of a surface-to-air missile (usually carries 50-150 kg of high explosives) and the yield of a surface-to-surface missile (usually carries 200-1000 kg of high explosive), that estimate gets reduced to around 80 megatons for the big guns. All well within standard sci-fi fare.

Ignoring the complete irrelevancy of that comparison,

No, let's not ignore the relevance, because I'm prepared to defend it. A modern ship will carry surface-to-surface missiles to deal with big targets (other ships) and surface-to-air missiles to deal with small ones (aircraft). The ISD carries heavy turbolasers to deal with other capital ships and light turbolasers to deal with smaler ones. The analogy seems pretty exact, and is just as likely to give a sense of the difference in firepower as a volumetric comparison, if not more likely.

Except it's a really silly comparison, since the difference between light and heavy turbolasers is power, and possibly range, whereas the difference between SAM's and SSM's is a completely different design because they're attacking different targets.

A better comparison would be between different gun calibres on battleships, since the essential technology and design ideas are the same, merely scaled up. For instance, the American Iowa class hips carried 16" main battery guns firing either 1,900 lb or 2,700 lb shells (the first being high explosive bombardment rounds, the latter being armour-piercing rounds). The 5" secondary batter fired 55 lb shells. Now that's total shell weight not explosive content, but it gives us a ratio of 34.5:1 (I used the 1900 lb HE shells for reference), which if we use the numbers you quoted, would give us around 120-130 megatons per shot for the heavy guns.

Of course, since the light turbolasers are being used in an essentially anti-aircraft role, we could just as validly use the 20mm Oerlikon rounds or the 40mm Bofors shells.

This simplistic comparison also forgets one crucial thing, we're comparing ships, not individual guns. An ISD will have 60+ twin-mounts of those light guns and anywhere from 12-64 of the heavies, with a rate of fire of around one shot per second or better. So, using these very loose and probably conservative numbers (120 light guns, 12 heavies, one shot per second) an ISD can pump out 1,920 megatons per second. That is well beyond what I know of B5 ships.

[Borgholio]

Of course, since the light turbolasers are being used in an essentially anti-aircraft role, we could just as validly use the 20mm Oerlikon rounds or the 40mm Bofors shells.

If you do that, and then compare to the super-heavy armor-piercing shell, you can easily get the half-gigaton firepower range for the heavy turbolasers.

[Eternal_Freedom]

Of course, since the light turbolasers are being used in an essentially anti-aircraft role, we could just as validly use the 20mm Oerlikon rounds or the 40mm Bofors shells.

If you do that, and then compare to the super-heavy armor-piercing shell, you can easily get the half-gigaton firepower range for the heavy turbolasers.

If we wanted to be really mean with this analogy, instead of the 2,700 lb AP shell, we could use the W23 20-kiloton nuclear shells they developed in the 50's.

[Borgholio]

Of course, since the light turbolasers are being used in an essentially anti-aircraft role, we could just as validly use the 20mm Oerlikon rounds or the 40mm Bofors shells.

If you do that, and then compare to the super-heavy armor-piercing shell, you can easily get the half-gigaton firepower range for the heavy turbolasers.

If we wanted to be really mean with this analogy, instead of the 2,700 lb AP shell, we could use the W23 20-kiloton nuclear shells they developed in the 50's.

Actually when I posted the pics of my USS Iowa trip a couple months back, I took a pic of the different ammo types. Strangely, I was more terrified by the description of the shell that drops 400 anti-infantry grenades over 9 acres than by the nuclear one.

[Simon_Jester]

One can (sort of) imagine the experience of watching it rain hand grenades all over nine acres of land. We have some concept of destructive accidents on the scale of a grenade blowing up, and then we just multiply.

No one who hasn't experienced one (and that is few) can readily picture what a nuclear initiation does to the surrounding land. It's very hard to imagine.

[Treknobabble]

Ignoring the complete irrelevancy of that comparison,

No, let's not ignore the relevance, because I'm prepared to defend it. A modern ship will carry surface-to-surface missiles to deal with big targets (other ships) and surface-to-air missiles to deal with small ones (aircraft). The ISD carries heavy turbolasers to deal with other capital ships and light turbolasers to deal with smaler ones. The analogy seems pretty exact, and is just as likely to give a sense of the difference in firepower as a volumetric comparison, if not more likely.

Except it's a really silly comparison, since the difference between light and heavy turbolasers is power, and possibly range, whereas the difference between SAM's and SSM's is a completely different design because they're attacking different targets.

It only makes sense to change power and range if one is intending to attack different targets with the weapons in question. Otherwise, why not just have all heavy turbolasers?

However, given that the operational principles of a gun are different from those of a missile, and given that the light turbolasers seem to be more of a secondary battery than a point defense system, a look at naval guns may be capable of giving us a better idea of what the heavy turbolasers would be capable of.

A better comparison would be between different gun calibres on battleships, since the essential technology and design ideas are the same, merely scaled up. For instance, the American Iowa class hips carried 16" main battery guns firing either 1,900 lb or 2,700 lb shells (the first being high explosive bombardment rounds, the latter being armour-piercing rounds). The 5" secondary batter fired 55 lb shells. Now that's total shell weight not explosive content, but it gives us a ratio of 34.5:1 (I used the 1900 lb HE shells for reference), which if we use the numbers you quoted, would give us around 120-130 megatons per shot for the heavy guns.

Let the record state that, had you used the 2,700 lb shells for reference, the firepower would have been closer to 200 megatons.

So a would a range from 120/200 megatons (from our analogies to "modern" ships) to 500 megatons (from volumetric considerations) be an acceptable one for estimating the power of a heavy turbolaser?

Of course, since the light turbolasers are being used in an essentially anti-aircraft role, we could just as validly use the 20mm Oerlikon rounds or the 40mm Bofors shells.

Hmmm. Let the record state that using a 2000 grain Oerlikon round would give us a value of 37.8 gigatons for the heavy turbolasers, whereas using a 2 lb Bofors shell gives us a value of 5.4 gigatons for the heavy turbolasers.

However, just as a battleship wouldn't use its AA guns to disable a fleeing corvette, I doubt that a Star Destroyer would use its point defense to disable Princess Leia's fleeing corvette. It was dealing with a large ship that it wanted intact, and a secondary battery would be ideal in such a situation. Moreover, a heavy turbolaser is only 5 times as long as a light turbolaser (125 times as massive). A 20 mm Oerlikon is 87 inches long, whereas the Mark 7 gun is some 68 feet in length. This gives a difference in size of some nine times (giving 825 times the volume). When compared to a Mark 12, we find that the Mark 7 gun in some 3.6 times longer (giving 48.5 times the volume).

It would thus appear that the comparison of an Iowa battleship's secondary battery to its main guns seems far more apt than my original proposal.

Conclusion: an ISD's light turbolasers can deliver 4 megatons with each shot, and its heavy turbolasers can deliver 200-500 megatons with each shot.

This simplistic comparison also forgets one crucial thing, we're comparing ships, not individual guns. An ISD will have 60+ twin-mounts of those light guns and anywhere from 12-64 of the heavies, with a rate of fire of around one shot per second or better

When have we observed such fire rates from an ISD?

So, using these very loose and probably conservative numbers (120 light guns, 12 heavies, one shot per second) an ISD can pump out 1,920 megatons per second. That is well beyond what I know of B5 ships.

It's hard to find numbers on B5 ships. However, assuming that they are armed with some kind of nuclear missiles in addition to their energy weapons, and assuming that the Imperial force is limited to the Death Squadron (~30 ships + the Executor), and assuming a Lanchesterian situation, even a yield of 50 megatons per second from each B5 YR ship would be sufficient to enable a sizable fleet (ie several hundred ships) to compete with the Star Destroyers.

[Simon_Jester]

Every single one of which can ignore any reasonable amount of YR ships with impunity.

Assuming we get a ten to one advantage with the YR ships, the required firepower advantage an ISD would need to have over a YR ship in order to win would be a hundred to one. Our calculations indicate a firepower disparity closer to 10:1.

An N-fold increase in quantity is as valuable as an N-squared-fold increase in quality.

The Lanchester Laws aren't meant to model this kind of combat, not on small scales. They don't talk about what happens when one combatant appears that can casually obliterate one of its enemies with one shot, while taking a massive amount of sustained barrage fire to put down.

This is why no number of rifle-armed infantry can realistically stop a tank, even though in theory one thousand rifle shots put out enough kinetic energy to equal one shell from an antitank gun. The tank can drive up to such a force, blast away until its ammunition or fuel runs low, and retreat, with virtual impunity. The Lanchester Laws don't affect this.

So basically, if an ISD is shielded to survive sustained fire from a ship of its own class, it will probably take a combined fleet with aggregate firepower greater than or equal to that in order to kill it. "Greater than," because the defending fleet's firepower will start to erode almost immediately as it takes losses, whereas a rival ship individually as powerful as the ISD would not erode right away.

Of course, a fleet that is not large enough to kill the ISD might theoretically 'drive it off' by simply remaining in the field long enough that the ISD exhausts its ammunition supply or its crew gets tired killing them or the combined bombardment somehow wears down the shields enough that the star destroyer captain decides to leave. But this would require absolutely ludicrous insensitivity to casualties, the sort of thing normally only seen in parody.

However, just as a battleship wouldn't use its AA guns to disable a fleeing corvette, I doubt that a Star Destroyer would use its point defense to disable Princess Leia's fleeing corvette. It was dealing with a large ship that it wanted intact, and a secondary battery would be ideal in such a situation.

Depending on whether the fleeing corvette has meaningful armor/shield protection, the battleship might do exactly that, and use Bofors guns (or hell, a .50 caliber bolted to the railing). Remember, Vader wants Leia (and her ship's computers, and apparently her ship's officers) alive. Any weapon powerful enough that it poses a high risk of overpenetrating and accidentally killing her would be a poor choice, whereas lightweight weapons capable of causing only the most superficial damage would be an excellent choice, as long as they can prevent her from escaping entirely.

Basically, if I'm on a battleship and I'm trying to stop a [url=http://en.wikipedia.org/wiki/Go-fast_boat]cigarette boat[/i], I'm not going to shoot it with a 5" gun. Sure, the 5" gun would stop it... but it would also blow the thing to kindling and scrap metal.

A similar argument applies to the Millenium Falcon, which is an even smaller and more lightly built ship. As I remember, on most if not all occasions where the Falcon is shot at by starship-grade weapons, the Imperial gunners have reason to want her taken more or less intact.

It would thus appear that the comparison of an Iowa battleship's secondary battery to its main guns seems far more apt than my original proposal.

Conclusion: an ISD's light turbolasers can deliver 4 megatons with each shot, and its heavy turbolasers can deliver 200-500 megatons with each shot.

Remind me again why we're assuming firepower scales perfectly with volume? Because if we follow this to its logical conclusion, I suspect we'll end up concluding that the Death Star is considerably less powerful than it needs to be to blow up planets. A heavy turbolaser turret is... somewhere between 10 and 100 meters in barrel length, compared to a superlaser roughly 100000 meters in barrel length, so the superlaser "should" have somewhere between one billion and one trillion times the power output... except that isn't anywhere near big enough, because your upper bound on turbolaser firepower is on the order of 10^19 joules per bolt.

It's hard to find numbers on B5 ships. However, assuming that they are armed with some kind of nuclear missiles in addition to their energy weapons, and assuming that the Imperial force is limited to the Death Squadron (~30 ships + the Executor), and assuming a Lanchesterian situation, even a yield of 50 megatons per second from each B5 YR ship would be sufficient to enable a sizable fleet (ie several hundred ships) to compete with the Star Destroyers.

It would be rather impractical to coordinate such a fleet against an overwhelmingly powerful opponent- but perhaps possible. Also, the reliance on massed barrages of nuclear missile fire is questionable for a number of reasons, among them missile fratricide.

And, again, the ability of ISDs to casually one-shot individual defending ships, while requiring the defenders to fire massed, sustained barrages to even seriously inconvenience them, tends to make a mockery of the Lanchester Laws, which are based on the assumption that all combatants on both sides are equally susceptible to being killed at all times, even if one side has less ability to do killing than the other.

[cmdrjones]

Every single one of which can ignore any reasonable amount of YR ships with impunity.

Assuming we get a ten to one advantage with the YR ships, the required firepower advantage an ISD would need to have over a YR ship in order to win would be a hundred to one. Our calculations indicate a firepower disparity closer to 10:1.

An N-fold increase in quantity is as valuable as an N-squared-fold increase in quality.

The Lanchester Laws aren't meant to model this kind of combat, not on small scales. They don't talk about what happens when one combatant appears that can casually obliterate one of its enemies with one shot, while taking a massive amount of sustained barrage fire to put down.

This is why no number of rifle-armed infantry can realistically stop a tank, even though in theory one thousand rifle shots put out enough kinetic energy to equal one shell from an antitank gun. The tank can drive up to such a force, blast away until its ammunition or fuel runs low, and retreat, with virtual impunity. The Lanchester Laws don't affect this.

So basically, if an ISD is shielded to survive sustained fire from a ship of its own class, it will probably take a combined fleet with aggregate firepower greater than or equal to that in order to kill it. "Greater than," because the defending fleet's firepower will start to erode almost immediately as it takes losses, whereas a rival ship individually as powerful as the ISD would not erode right away.

Of course, a fleet that is not large enough to kill the ISD might theoretically 'drive it off' by simply remaining in the field long enough that the ISD exhausts its ammunition supply or its crew gets tired killing them or the combined bombardment somehow wears down the shields enough that the star destroyer captain decides to leave. But this would require absolutely ludicrous insensitivity to casualties, the sort of thing normally only seen in parody.

However, just as a battleship wouldn't use its AA guns to disable a fleeing corvette, I doubt that a Star Destroyer would use its point defense to disable Princess Leia's fleeing corvette. It was dealing with a large ship that it wanted intact, and a secondary battery would be ideal in such a situation.

Depending on whether the fleeing corvette has meaningful armor/shield protection, the battleship might do exactly that, and use Bofors guns (or hell, a .50 caliber bolted to the railing). Remember, Vader wants Leia (and her ship's computers, and apparently her ship's officers) alive. Any weapon powerful enough that it poses a high risk of overpenetrating and accidentally killing her would be a poor choice, whereas lightweight weapons capable of causing only the most superficial damage would be an excellent choice, as long as they can prevent her from escaping entirely.

Basically, if I'm on a battleship and I'm trying to stop a [url=http://en.wikipedia.org/wiki/Go-fast_boat]cigarette boat[/i], I'm not going to shoot it with a 5" gun. Sure, the 5" gun would stop it... but it would also blow the thing to kindling and scrap metal.

A similar argument applies to the Millenium Falcon, which is an even smaller and more lightly built ship. As I remember, on most if not all occasions where the Falcon is shot at by starship-grade weapons, the Imperial gunners have reason to want her taken more or less intact.

It would thus appear that the comparison of an Iowa battleship's secondary battery to its main guns seems far more apt than my original proposal.

Conclusion: an ISD's light turbolasers can deliver 4 megatons with each shot, and its heavy turbolasers can deliver 200-500 megatons with each shot.

Remind me again why we're assuming firepower scales perfectly with volume? Because if we follow this to its logical conclusion, I suspect we'll end up concluding that the Death Star is considerably less powerful than it needs to be to blow up planets. A heavy turbolaser turret is... somewhere between 10 and 100 meters in barrel length, compared to a superlaser roughly 100000 meters in barrel length, so the superlaser "should" have somewhere between one billion and one trillion times the power output... except that isn't anywhere near big enough, because your upper bound on turbolaser firepower is on the order of 10^19 joules per bolt.

It's hard to find numbers on B5 ships. However, assuming that they are armed with some kind of nuclear missiles in addition to their energy weapons, and assuming that the Imperial force is limited to the Death Squadron (~30 ships + the Executor), and assuming a Lanchesterian situation, even a yield of 50 megatons per second from each B5 YR ship would be sufficient to enable a sizable fleet (ie several hundred ships) to compete with the Star Destroyers.

It would be rather impractical to coordinate such a fleet against an overwhelmingly powerful opponent- but perhaps possible. Also, the reliance on massed barrages of nuclear missile fire is questionable for a number of reasons, among them missile fratricide.

And, again, the ability of ISDs to casually one-shot individual defending ships, while requiring the defenders to fire massed, sustained barrages to even seriously inconvenience them, tends to make a mockery of the Lanchester Laws, which are based on the assumption that all combatants on both sides are equally susceptible to being killed at all times, even if one side has less ability to do killing than the other.

https://en.wikipedia.org/wiki/Lanchester's_laws

Y'know... you'd think that this really wouldn't apply, but with the advent of Shielding and with massive ships that maneuver comparatively slowly, this may have more of an application than we think. I agree though that unless a B5 force can punch through and ISDs shields with a single volley, they'll be attritted faster than they can damage a SW shielded ship....
Assuming the B5 powers figure this out relatively quickly, they will know flat out that they don't have a hope of beating ISDs in the open and resort to guerrilla tactics (or just surrender), or that they will HAVE to go for a huge one shot alpha strike designed to overwhelm the ISD before it can blast them all to dust.