Question from a friend/Bacta War/Shields/Torpedoes

McC · Post by **McC** » 2005-05-27 03:51pm

A friend posed this question to me today:

My friend wrote:How many proton torpedos would be needed to take down a star destroyer? Assuming it isnt fighting back or anything, and just taking it.

I responded with the following:

I wrote:Technically speaking, you could lob an infinite number of torpedoes at a star destroyer and it would just smile at you.

Shields work by dissipating the energy thrown at them. Star destroyer shields are particularly powerful. In the extended literature (and the movies), the only way to take down shields is to overwhelm their dissipative capabilities with a huge surge of firepower ("Concentrate all fire on that super star destroyer!") which you need to target at a shield generator. The idea is to punch through the shields and damage a local projector so that you can then attack the hull.

There's a particularly good example of this in one of the X-wing books. There's also a weapon called a Torpedo Sphere used for planetary sieges. What it does is basically sit in orbit and lob ungodly amounts of torpedoes at the same exact spot on the shields until they overwhelm the shield and punch through, destroying the planetary projector.

I didn't want to leave him with my vague assertions, so I poked around the board for a bit to find the particular X-wing quote in question. I then told him this (bold emphasis mine, added to point out relevant parts):

Then I wrote:Quote from "Bacta War" (bold emphasis mine):
Engaging in a straight-up fight with even a Victory-class Star Destroyer like the Corrupter would be suicide for a squadron of X-wings. [..] If the whole squadron fired a salvo of torpedoes at the same time, they could certainly bring the Star Destroyer's shields down, but any captain worth his rank cylinders would roll the ship to present undamaged shields and keep shooting.

Followed with:

I then wrote:A squadron in SW is 12 ships. X-wings each carry 6 torpedoes, fired in 'salvos' of 2. So if the entire squadron (12) fired a salvo of torpedoes (12*2 = 24) at the same time, they'd take down one facing of a Victory (smaller, weaker than Imperator-class seen in the OT movies) destroyer's shields, at which point the ship can simply be rolled over so the other side of its shields can block incoming fire.

From "Essential Guide to Weapons and Technology":
When overloaded by incoming energy charges, a shield projector's matrix boards will burn out rather than flooding the generator with energy and destroying the entire shield system. Tech crews can repair burned out-out projectors in just a few minutes to get the shields back up to full power.

So repairing that much shield collapse takes a matter of minutes. Attacking a capital ship with starfighters alone is a bad plan

So, having said all that, I have a few questions of my own.

Did I explain it to him correctly, more or less? I know I glossed over a few things, but he's not a tech-centric guy. As a layman's definition, how is it?

Given that we now know the reactor power of Venators, and that Victorys are roughly analogous warships, is it possible to codify the precise amount necessary to overload a shield facing on a Victory, given the above quote? If so, what is it?

Ender · Post by **Ender** » 2005-05-27 03:55pm

1) yes, you did all right
2) No. the yield of the torps is unknown, as is the dissipation rate for shields, and how to etermine it. I have a theory on it though, and I'm trying to find a way to test it through CAD programs and ship meshes.

McC · Post by **McC** » 2005-05-27 04:01pm

Ender wrote:2) No. the yield of the torps is unknown, as is the dissipation rate for shields, and how to etermine it. I have a theory on it though, and I'm trying to find a way to test it through CAD programs and ship meshes.

Want to share it with the whole class? Or at least PM me about it?

Praxis · Post by **Praxis** » 2005-05-28 12:36am

Yep, thats correct. It should be noted that its a quick downing, because they can get the shields back up in under a minute. According to the book he can roll and by the time the fighters move around it to get at the downed side it would be back up again.

Ender · Post by **Ender** » 2005-05-28 12:02pm

McC wrote:
Ender wrote:2) No. the yield of the torps is unknown, as is the dissipation rate for shields, and how to etermine it. I have a theory on it though, and I'm trying to find a way to test it through CAD programs and ship meshes.
Want to share it with the whole class? Or at least PM me about it?

In brief, I'm trying to get figures for the volume and surface area of a bunch of ships to see if there is some common thread there. Afterall, shields work by reradiation and reradiation (and thus shield strength) are proportional to surface area. Likewise, there is a rough corrolation between volume and reactor power. Then there is the obvious connection of volume and surface area. I intend to cross check all of these to try and figure out if there is some kind of scale that can then be extrapolated to cover ships we don't have shield numbers for.

Eville Jedi at TFN has made mantion of doing this kind of work in the fleet junky thread there (notably when he slapped Brett Bass around on "Venators cant hold all those starfighters!"), I plan to ask him.

Illuminatus Primus · Post by **Illuminatus Primus** » 2005-05-28 01:18pm

Bass is an idiot. For being a Marine he certainly knows jack and shit about anything.

McC · Post by **McC** » 2005-05-28 02:42pm

Ender wrote:In brief, I'm trying to get figures for the volume and surface area of a bunch of ships to see if there is some common thread there. Afterall, shields work by reradiation and reradiation (and thus shield strength) are proportional to surface area. Likewise, there is a rough corrolation between volume and reactor power. Then there is the obvious connection of volume and surface area. I intend to cross check all of these to try and figure out if there is some kind of scale that can then be extrapolated to cover ships we don't have shield numbers for.

Oh hell. I suddenly wish LightWave were still working. My hardware dongle for it is physically busted, so I can't run the program (and haven't gotten around to getting myself a new dongle, since I've switched from LightWave to Maya), but there was a free plugin for it that would instantly calculate both the volume and surface area of any object you threw at it. Would've been perfect for this, assuming the models were available for download (and many are).

I suppose I could look around for such a plugin for Maya, if it would be useful to do so.

Post by **Alyrium Denryle** » 2005-05-28 02:51pm

I seem to remember somewhere that by firing proton torps in a slightly staggered manner(one right after the other) that it was possible to cause a distortion in the particle shields that would allow another torp to slip past and damage a surface target. COrrect me if I am wrong here

McC · Post by **McC** » 2005-05-28 02:54pm

McC wrote:I suppose I could look around for such a plugin for Maya, if it would be useful to do so.

Found one.

Let me know if you want any measurements, Ender, and I'll see what I can do.

Ender · Post by **Ender** » 2005-05-28 03:45pm

McC wrote:
McC wrote:I suppose I could look around for such a plugin for Maya, if it would be useful to do so.
Found one. Let me know if you want any measurements, Ender, and I'll see what I can do.

Surface area and volume, as accurate as possible, for the Senatorial barge, Acclamator, Senatorial Yacht, coreship, Executor (remember to adjust for the now slightly larger command tower size and scale up), and Imperator class please.

McC · Post by **McC** » 2005-05-28 04:47pm

Ender wrote:Surface area and volume, as accurate as possible, for the Senatorial barge, Acclamator, Senatorial Yacht, coreship, Executor (remember to adjust for the now slightly larger command tower size and scale up), and Imperator class please.

Okay, two roadblocks:

This plugin may be calculating the surface area of all of the polygons, regardless of whether or not the polygon represents an exposed portion of the ship. Same for volume.

Some of these models are over a million polygons, and aren't exactly meant to have volume calculations run on them (the Imperator model in particular seems to like to just crash the volume calculator).

I can, however, approximate in much lower detail these same sizes using the complex models as a template. Would this be sufficient? Essentially, the entire brim trench consists of thousands of polygons, and only needs to really consist of 1 for these purposes, I'd think. Is that alright?

Also, senatorial barge/yacht? Which ships are those? I'm guessing that the yacht is the Naboo ship from TPM and the barge is the Naboo ship from the beginning of AOTC. Furthermore, what length am I to use for the Executor? Your statement indicates (most likely rightly so) that the 17.6 km figure is in fact too small (probably going off of the ROJ scene with the Lambda being very tiny).

nightmare · Post by **nightmare** » 2005-05-28 09:49pm

Alyrium Denryle wrote:I seem to remember somewhere that by firing proton torps in a slightly staggered manner(one right after the other) that it was possible to cause a distortion in the particle shields that would allow another torp to slip past and damage a surface target. COrrect me if I am wrong here

I wonder if not this is in regarding to Vong dovin basals rather than shields.

Post by **Mr Bean** » 2005-05-28 11:12pm

nightmare wrote:
I wonder if not this is in regarding to Vong dovin basals rather than shields.

No its for shields, Firing torps at the same spot with enough power behind them won't bring them down, but it can buckle them temporarly, or knock down a hole through the shield temporarly(Handful of seconds according to EU) which can let a torp or two slip through, hit the armor and possibly take out a shield emitter or two

Ender · Post by **Ender** » 2005-05-29 12:15am

McC wrote:
Ender wrote:Surface area and volume, as accurate as possible, for the Senatorial barge, Acclamator, Senatorial Yacht, coreship, Executor (remember to adjust for the now slightly larger command tower size and scale up), and Imperator class please.
Okay, two roadblocks:
This plugin may be calculating the surface area of all of the polygons, regardless of whether or not the polygon represents an exposed portion of the ship. Same for volume.

My ignorance on the subject means I'm gonna have to assume that's really bad.

Some of these models are over a million polygons, and aren't exactly meant to have volume calculations run on them (the Imperator model in particular seems to like to just crash the volume calculator).

I see my assumption is correct.

I can, however, approximate in much lower detail these same sizes using the complex models as a template. Would this be sufficient? Essentially, the entire brim trench consists of thousands of polygons, and only needs to really consist of 1 for these purposes, I'd think. Is that alright?

Should work I think.

Also, senatorial barge/yacht? Which ships are those? I'm guessing that the yacht is the Naboo ship from TPM and the barge is the Naboo ship from the beginning of AOTC.

Barge is the ship from the start of AOTC, Yacht is the ship from later in AOTC.

Furthermore, what length am I to use for the Executor? Your statement indicates (most likely rightly so) that the 17.6 km figure is in fact too small (probably going off of the ROJ scene with the Lambda being very tiny).

Dr Saxton has the exact ratio on his site, but basically, 270 meters gets you the 17.6 value, but the new value is 294 or so. Have to adjust the dimensions as a result.

McC · Post by **McC** » 2005-05-29 01:41am

Ender wrote:My ignorance on the subject means I'm gonna have to assume that's really bad.

I see my assumption is correct.

Hehe. More than just that, though, the shield isn't going to cover, say, the mounting point inside the hull where the sensor globe towers bolt into the command tower. However, there's geometry there, so the calculation will end up including that for surface area/volume, even though the shield won't actually be there.

Should work I think.

Okay, I'll get cracking on that.

Barge is the ship from the start of AOTC, Yacht is the ship from later in AOTC.

Aha, gotcha. I don't think models of those ships are available for free download at the moment, but I'll keep looking.

Dr Saxton has the exact ratio on his site, but basically, 270 meters gets you the 17.6 value, but the new value is 294 or so. Have to adjust the dimensions as a result.

19.16km, then.

McC · Post by **McC** » 2005-05-29 03:35am

Okay, as an experiment, here's what I got for Executor using my "simple model replacement" method:

Given: Length of 19.16km

Measured: Length of 18.832497 units

Measured: Surf. Area of 151.687254 units^2

Calculated: Surf. Area of 157 km^2

Measured: Volume of 61.162587 units^3

Calculated: Volume of 63.3 km^3

If those are close to what one would expect for Executor, then I'll continue with the other ships. If those seem off, then I'll have to rethink my methodology

Ender · Post by **Ender** » 2005-05-29 03:41am

I'd say that's about right, thanks

McC · Post by **McC** » 2005-05-31 12:34am

Here's Imperator.

Given: Length of 1.600km

Measured: Length of 69.85001 units

Measured: Surf. Area of 4570.825002 units^2

Calculated: Surf. Area of 2.398km^2

Measured: Volume of 10709.75505 units^3

Calculated: Volume of 5.619km^3

How do those hold up to expectations?

Mad · Post by **Mad** » 2005-05-31 01:20am

Praxis wrote:Yep, thats correct. It should be noted that its a quick downing, because they can get the shields back up in under a minute. According to the book he can roll and by the time the fighters move around it to get at the downed side it would be back up again.

More precisely:

The Bacta War, pg 198 wrote: Wedge felt a moment's joy at the collapse of the Corrupter's shields, but it died as the big ship began to maneuver. It rotated in space above him, executing a roll that swapped up for down and presented the squadron with its undamaged starboard shields as a target. Convarion knows we have a limited supply of proton torpedoes. If he survived this salvo, we've got one last shot to take him down. If he repairs his shields and rolls again, we're done, because then he can take all the time he wants to come after us.

The point is clear: a lone squadron of the best pilots around don't stand a chance against a Victory Star Destroyer with a competent command.

Grandmaster Jogurt · Post by **Grandmaster Jogurt** » 2005-05-31 03:01am

Are you sure that volume for the ISD is correct? Even if it was a cube 1.6 km to a side, it would be smaller than that figure.

McC · Post by **McC** » 2005-05-31 03:07am

Grandmaster Jogurt wrote:Are you sure that volume for the ISD is correct? Even if it was a cube 1.6 km to a side, it would be smaller than that figure.

I find both of the figures to be highly suspect, actually.

While the Executor figures suggest a very big number for the surface area, and a smaller number for the volume, these numbers are reversed. I'll look into it further.

McC · Post by **McC** » 2005-05-31 04:23pm

Okay, I'm now fairly sure the surface area figure is correct. Just using a basic triangle for reference, I figured out the area of said triangle using the width of the ISD and the length of the ISD as parameters (45.68x69.85) and it worked out to 3190.748 units^2. The measured figure was 1400 units^2 bigger, which makes plenty of sense given the engine wells, trenches, and superstructure aren't accounted for in my rough estimate.

I also found the problem with the volume figure. The short version is, "Ryan is dumb."

You were correct in saying that a cube 1.6km on all sides would have a lesser volume (4.096 km^3). I went into Maya to calculate the volume of a cube matching the bounding box dimensions of an ISD and came out with a volume of 67,101 units. This was, clearly, much larger than the 10,709 units that's calculated, suggesting that everything was fine on the calculation end. It was when I went into Excel to check the conversion that I realized the problem: the volume column was still using units squared, rather than units cubed.

That said, here's the corrected volume data:

Executor

Measured: Volume of 61.162587 units^3

Calculated: Volume of 64.4 km^3

Imperator

Measured: Volume of 10709.75505 units^3

Calculated: Volume of 0.1287 km^3

Much better

Ender · Post by **Ender** » 2005-05-31 06:34pm

Now that is odd, there should only be a difference of x100 between the two.

McC · Post by **McC** » 2005-05-31 06:42pm

Ender wrote:Now that is odd, there should only be a difference of x100 between the two.

Why's that?

I just re-checked both the measurement and my Excel units conversion and they both verify...

Ender · Post by **Ender** » 2005-05-31 09:47pm

McC wrote:
Ender wrote:Now that is odd, there should only be a difference of x100 between the two.
Why's that? I just re-checked both the measurement and my Excel units conversion and they both verify...

ITW OT says the mass difference between the two is over a hundred, which means its only slightly mroe then that, otherwise it would have been 110x, or 105x etc. I presume this statemetn comes from the evidence and a constant density.