ISD. A serious design flaw.

[JodoForce]

What is important in a world with 70km/s/s maneuvers is probably suddeness. Even if the enemy is more maneuverable, a sudden, 70km/s delta-v on an enemy that's just sitting on your bottom should throw him off.

This assumes the helm is solely under human control, which I doubt.

The ship can also risk the maneuver and just roll REGARDLESS of the frigate. In a battle environment, if the ISD is under threat from collision, so is the frigate. Just play a game of chicken. This game favors the larger ship, and the enemy captain would probably wimp out and take evasive action.

hmmkay...

[vakundok]

Certainly in the novels they do, and 3D maneuvering is a part of every space vessel. If the Captains can't use it, it is their tactical stupidity. The best design cannot compensate for tactical stupidity.

In which novels? You mean sliding or off-axis movement? No, it is not an automatic feature on space vessels. Besides, in TESB did the two approaching destroyers slide, which would be the most effective way to avoid collision? No, they did not. They tried to turn.

Well, Dreadnaughts DO have maneuvering thrusters (Hutt Gambit) so I can't see why the ISD would not. You will notice my strategy requires NO thrust vectoring, just a usage of both the horizontal and vertical planes to "dive" down into the ideal attack position, which is ventral and up the enemy's ass - about as good as any Captain could ask for.

Yes, it works correctly. Until your opponent tries to survive and starts to maneuver downwards. Then, you will have to dive again and again. And turning down, moving and turning up sounds more difficult to me than just turning down (for only the first time) and moving.

The ISD's length is 1600m, its width is about 880m and its height is about 455m (scaling from the EGVV diagram.)
A frontal aspect is width times height: 880*455.
Find a picture or diagram of a Star Destroyer side view (plenty of those floating on the web. Cut the Star Destroyer out as closely as you can. I cropped mine accurate to a few pixels - I used Paint.
My original picture (unrotated) had a height of 181 pixels. After a 15 degree rotation of the Star Destroyer, I cropped out the space around the Star Destroyer again. It blew up to 271 pixels in height. Only 50% larger, and a Star Destroyer is already so big that does it matter?

You seem to forgot that the shape of the target surface is changing too. On a frontal view there are large holes on the sides of the superstructure, which are partially filled when the ship is turned down. But let's count as 50%. It means 50% higher chance to hit despite the ECM or the same target surface from 20% farther. Yes, it matters.

Yes, we all know superfiring would solve THIS problem. But just because superfiring works for a small gun turret does not mean it'll work with those big behemoths, with their much larger recoil and support requirements.

First of all, the "small cannon"-"big behemoth" comparison does not fit. The main cannons of the ISD II are not several times larger (actually 40-50%).
The main turrets can turn. It means that they solved those problems within a structure that capable of moving. Do you seriously state that they canot solve it within a fixed structure (the elevation)? Do you seriously say that eg: "The recoil of the guns do not take apart those small support structures (the actual turrets of the ISD II are really small), but would take apart a magintude larger and fixed elevation structure"?

I mentioned only a single frigate in my theory. What about four or five? Most likely three of them can find their ways to that position. One positioning directly under the hangar bay, the two others just besides the bulb.
-Rolling: Very risky as I wrote. (Imagine colliding a shielded frigate and the shielded hangar bay.)
-Quick acceleration and decceleration: During this the frigate under the bay will collide with the bulb. The two others will be behind and still under the ISD. So the ISD still need to turn and roll to fire back (which gives time the frigates to reposition) and the ventral shield is already damaged. Do you remember the new position of the frigates?

[JodoForce]

1 ISD = bad idea
2 ISDs = forget all about these fancy tactics

[vakundok]

1 ISD = bad idea
2 ISDs = forget all about these fancy tactics

If a lone ISD is so endangered, doesn't it mean that the design is flawed?
Tactics based on retreating still work finely against multiple ISD IIs.

[nightmare]

I'm interested in seeing the appropriate evidence for an extendable superfiring system for the ISD octuples. That idea sounds cute (and would afford about 10-20 more degrees of elevation arc for the HTLs,) but there are technical problems, versus say a Fixed Superfiring turret configuration.

Sure, now you can retract the turret to the lowest (and presumably most secure) position before a hyperjump. Beyond that, it is hard to see any advantage. The Extend-Retract device reduces structural integrity when the turret is in the Raised Position and is another failure point. And how does go from Retract to Extend. Is it some kind of pneumatic system, so the gun goes "hiss" and goes straight up? Or is it some kind of slow, screwlike system so the gun has to turn several rounds counterclockwise before going to the raised position?

I was surprised too when I first read it. It was quite some time ago and I only have vague memories of it, so I may be somewhat wrong here. IIRC, it was an illustration that was the basis of that argument, and I think it was a straight-up kind of thing. Sorry, but I can't be more helpful than that.

[JodoForce]

If you look at the scenarios I posted in the last page you'd see that one lone ISD wins some and loses some against an ISD with modified weapons layout, and twin ISDs ownz all against double the opposition.

Whereas the concentrated fire design is quite necessary for efficiency and extra firepower in fleet actions...

And it's not like you can mount 8 HTLs so they can all fire out the front can you?

An ISD rolled 10 degrees down is not heading directly towards the enemy but is still mostly heading in its direction...

As for the enemy going downwards, well that's fine, at least they're not running away anymore, as the range closes you can finish it off all the more quickly

[Kazuaki Shimazaki]

I meant 3D maneuvering in general, whether aerodynamic-like style or pure Newton reaction style or a combo. Or do you intend to tell me a Star Destroyer cannot maneuver in one of the X, Y, and Z dimensions. I try to do things to minimize things like sliding. If the vessel can turn down (officially stated,) fire its engines ahead, and turn back up like a plane, it can do what I ordered it to do. For my clear arc maneuvers, in fact, we do turn. No slide, no pivot (though of course they're welcome,) just roll (and the simple fact they can ROLL implies they have maneuvering thrusters of a sort.

If the guy changes his own vector to try and stay on my ventral side. Well, then he isn't running straight away anymore, is he? He has a lot more ground to cover. I have to pitch down. He has to run about me in this circle whose circumference is determined by how far he is from me (the farther he is, the easier my job is versus his if I just want to shoot at him.)

The point about the extra matter coming up is a good one that I've honestly forgotten. OK, fine, it is a problem, and if you count that part, it will probably be 70% or more of an increase. But then most Terran gun warships also have this problem. They have to turn and thus expose more (and it is not by 15, it is often more like turn by 20 or even 30) to use broadside (and for them full gunfire.) It does cost them. Yet nobody ever calls that a flaw, just a compromise. Very few (only the French AFAIK) tries to solve it by sticking all the guns in the bow, yet another compromise.

There's obviously (at least if we assume they weren't idiots) a line of feasibility they crossed somewhere if they superfired one (proving they know the concept) and not the other. You mean the Axial Defence Turrets (ICS term). They are measured to be maybe 10m long. and the primaries are about 14m, BUT the Axial Defences are TRIPLES and the Primaries are OCTUPLES. If we assume they have the same firepower per barrel, the octuples each pack about 2.66 times the firepower (and thus recoil) of the triples. Probably more like 300 percent at least once you take into account the longer length.

The main turrets do have traverse and elevation of course. But superfiring means you have to raise the traverse, elevation and recoil handling mechanisms somehow. To say nothing of an extendable design. You have them raised. Your turret suddenly became heavier due to its extra height, used more material, and places a greater structural strain on everything else when it fired. Worst case is that it might "snap" the superfiring "tower" used to raise to to position. I'm sure you can compensate for the extra weight and strain, but that's extra money, which goes to another debate.

It is a compromise. I'm sure I've said once before that if we don't care about cost or complexity or technical problems, we should put all the turrets on the dorsal centerline, and implement superfiring not by elevating them on a "pole", but by spacing them out on the sloped hull so they NATURALLY superfire each other even if they just stick out of the hull. Obviously, they are either idiots, or there is something else stopping them.

Your frigate scenario is turning more and more into one that goes like this: I have a gun. You say "What happens if there are five of me, and we are all in ideal stabbing positions with knives?" I'll deal with it in a separate post.

[vakundok]

If you look at the scenarios I posted in the last page you'd see that one lone ISD wins some and loses some against an ISD with modified weapons layout, and twin ISDs ownz all against double the opposition.

Whereas the concentrated fire design is quite necessary for efficiency and extra firepower in fleet actions...

And it's not like you can mount 8 HTLs so they can all fire out the front can you?

An ISD rolled 10 degrees down is not heading directly towards the enemy but is still mostly heading in its direction...

As for the enemy going downwards, well that's fine, at least they're not running away anymore, as the range closes you can finish it off all the more quickly

First of all, in my opinion, a ten degrees turn is not enough. I watched the side views of the Avenger on Saxton's page, and the guns require at least 12 or 13 degrees to fire forward. And it is barely enough against a completely stationed target. Besides, 10 degrees will not really cover the bulb. So, for these reasons I use the 15 degrees which covers the bulb and provides a small window to fire.

Theoretically: place two turrets (in superfiring position to front) on the right and left dorsal side and two others to the right and left ventral side. All eight can fire directly forward, four to the sides, and they have more firepower to the rear then previously. Besides no enemy can maneuver in front of you to not to face at least two turrets. Your maximum firepower is paired with the smallest possible target surface and you can approach or follow your opponent without loosing firepower. The hangar bay and the bulb is more exposed to enemy fire, but it matters only after you lost your shield in which case your tower (bridge) will be exposed anyway. It also makes the "smaller ships under the ventral side" largely ineffective.

I posted the retreating tactics on the first page. I used an ISD I as an example but the situation is far worst for an ISD II. What could the two ISD IIs do in that situation? Facing "mostly" toward a ship is not enough to follow it with full speed.

[Kazuaki Shimazaki]

First of all, in my opinion, a ten degrees turn is not enough. I watched the side views of the Avenger on Saxton's page, and the guns require at least 12 or 13 degrees to fire forward. And it is barely enough against a completely stationed target. Besides, 10 degrees will not really cover the bulb. So, for these reasons I use the 15 degrees which covers the bulb and provides a small window to fire.

Yes, we are using 15 degrees now in our debates. We just loose about one or two percent more speed.

Theoretically: place two turrets (in superfiring position to front) on the right and left dorsal side and two others to the right and left ventral side. All eight can fire directly forward, four to the sides, and they have more firepower to the rear then previously. Besides no enemy can maneuver in front of you to not to face at least two turrets. Your maximum firepower is paired with the smallest possible target surface and you can approach or follow your opponent without loosing firepower. The hangar bay and the bulb is more exposed to enemy fire, but it matters only after you lost your shield in which case your tower (bridge) will be exposed anyway. It also makes the "smaller ships under the ventral side" largely ineffective.

That's the same as Frank's solution, except you added superfiring. Not debating whether we can really superfire the octuples (somehow I doubt they wouldn't if they could economically)... You are not really adding much to the rear fire part of the solution. Your solution in fact is another compromise - dispersing your firepower. You still have a full-fire capability, but instead of moving out of a Elevation 15-90 degree arc, now one's task is simplified to moving out of a 20 degree arc, beyond which your forward firing guns will hit the hull. Against a major threat opponent to your hull. He can choose your ventral hull, and supposing he's an ISD-II, he can now choose an optimum angle where his 8 guns match against your four. Different threats, different dangers, more chances, less chances.

I posted the retreating tactics on the first page. I used an ISD I as an example but the situation is far worst for an ISD II. What could the two ISD IIs do in that situation? Facing "mostly" toward a ship is not enough to follow it with full speed.

If you are chasing a guy at 100km/s (say) on the X axis, and you pitch down 15 in the Z (height) axis, you are still moving at about 96.59% of your original speed in the X-axis. Not a huge, irrecovable loss. Plus you are getting free slams into his engine, some of which will penetrate and reduce the efficiency of HIS engine. A 5% difference is small. Maneuvering skill, the state of the engines that day ... all can do quite a bit to compensate. Just the fact he's RETREATING suggests he's not doing so great - if he's retreating despite looking great, I might actually pursue him only slowly and cautiously because he might be trying to set me up.

[vakundok]

I meant 3D maneuvering in general.

OK.

If the guy changes his own vector to try and stay on my ventral side. Well, then he isn't running straight away anymore, is he? He has a lot more ground to cover. I have to pitch down. He has to run about me in this circle whose circumference is determined by how far he is from me (the farther he is, the easier my job is versus his if I just want to shoot at him.)

I didn't write it, so I apologize, but I ment that it tried to get out of range. (My retreating tactics, you know.) So, you canot stay in place and just pitching down. You most follow or leave it.

The point about the extra matter coming up is a good one that I've honestly forgotten. OK, fine, it is a problem, and if you count that part, it will probably be 70% or more of an increase. But then most Terran gun warships also have this problem. They have to turn and thus expose more (and it is not by 15, it is often more like turn by 20 or even 30) to use broadside (and for them full gunfire.) It does cost them. Yet nobody ever calls that a flaw, just a compromise.

See my theoretical main weapon arrangement. This compromise is unneeded. I call an unneeded compromise as a design flaw.

There's obviously (at least if we assume they weren't idiots) a line of feasibility they crossed somewhere if they superfired one (proving they know the concept) and not the other.

Yes. But unless we know this line it is an unneeded compromise. We can also assume that the designers simply did not face the problem since there were no real opposition when the ISD II was designed.

Your turret suddenly became heavier due to its extra height, used more material, and places a greater structural strain on everything else when it fired.

Simply no. The turret remains the same, only the hull under te turret is elevated. Watch the support structure (that actually holds the guns) of the main guns of the ISD II. They can handle the strain caused by the guns and they are very small. Saying that handling this strain could pose any problem to a hull elevation under the turret is beyond me.

Your frigate scenario is turning more and more into one that goes like this: I have a gun. You say "What happens if there are five of me, and we are all in ideal stabbing positions with knives?" I'll deal with it in a separate post.

Yes, largely. Except that you shoot down two of me during the positioning and five of me are nowhere in relation to you (in terms of resources), which makes the situation imaginable (to me). I am waiting for it, but I will not be available from friday.

[vakundok]

That's the same as Frank's solution

Yes, it is a very simple (and most likely a quite old) solution.

You still have a full-fire capability, but instead of moving out of a Elevation 15-90 degree arc, now one's task is simplified to moving out of a 20 degree arc, beyond which your forward firing guns will hit the hull. Against a major threat opponent to your hull. He can choose your ventral hull, and supposing he's an ISD-II, he can now choose an optimum angle where his 8 guns match against your four. Different threats, different dangers, more chances, less chances.

For a "largely sitting and shooting each other" scenario there is only minimal difference between the two designs. This modified is slightly better due to the smaller target profile required for concentrated fire.

If you are chasing a guy at 100km/s (say) on the X axis, and you pitch down 15 in the Z (height) axis, you are still moving at about 96.59% of your original speed in the X-axis. Not a huge, irrecovable loss. Plus you are getting free slams into his engine, some of which will penetrate and reduce the efficiency of HIS engine. A 5% difference is small. Maneuvering skill, the state of the engines that day ... all can do quite a bit to compensate. Just the fact he's RETREATING suggests he's not doing so great - if he's retreating despite looking great, I might actually pursue him only slowly and cautiously because he might be trying to set me up.

It was a long range situation where the distance was important due to the range of the guns. Even with 1% of difference it will be out of range soon. You canot pursue it slowly and cautiously.

We should consider one thing:
Can the ISD accelerate directly toward 15 degrees off-axis or not?
I say not or only in an extremely limited manner (one or two percent of their forward thrust). It is based on mechanics, and that the ISD does not have large enough (visible) thrusters to compensate the rotation. It is harmonious with the "collision" in TESB.

[JodoForce]

No they can't accelerate directly towards the enemy anymore.
The acceleration towards the target would be something like *cos 15deg = 96.6% of what it would have been had it been going directly towards the target

1% difference -> out of range? You must have been playing too much X-Wing Real weapons don't work that way.

[vakundok]

No they can't accelerate directly towards the enemy anymore.
The acceleration towards the target would be something like *cos 15deg = 96.6% of what it would have been had it been going directly towards the target
1% difference -> out of range? You must have been playing too much X-Wing Real weapons don't work that way.

And there will be a sin 15deg=25.9% which will only enlarge the distance between the two ships.

If I remember well, the novelization of TESB (or maybe ANH?) mentioned out of range (most likely turbolaser) blasts from an ISD, but I am not sure.
So, how do the weapon systems of the ISDs work? Do they have range at all? Doesn't the "out of range" mean that the power of the blast is significantly lower than would be effective or the target is too far away to be targeted by the computers? Or doesn't the "long range confrontation" mean that the distance is close to the maximum range, when enlarging the distance will result "out of range" soon?

[JodoForce]

And there will be a sin 15deg=25.9% which will only enlarge the distance between the two ships.

Nope, that component will be perpendicular to the direction of the target ship, taking the ISD straight down but not away from the ship.

As the ISD gains on the target this downward component may increase, in which case just roll up gently to keep the incident angle at 15deg.

I'm not basing my interpretation about TL in-range / out-of-range questions based on anything in SW--common sense just tells me that a TL bolt won't be ready to eat a gaping hole in neutronium armor one second then stop dead in its tracks and vaporize into nothingness the next (or one km away)

[vakundok]

Nope, that component will be perpendicular to the direction of the target ship, taking the ISD straight down but not away from the ship.

An example: The distance between the two ships is four unit. Both have the same horizontal movement but one of them also has a vertical component that causes it 3 unit downwards (after a while). The distance will increase by one unit only because that vertical component.

I'm not basing my interpretation about TL in-range / out-of-range questions based on anything in SW--common sense just tells me that a TL bolt won't be ready to eat a gaping hole in neutronium armor one second then stop dead in its tracks and vaporize into nothingness the next (or one km away)

As I wrote the range can also mean the distance from what the sensors can detect the ship (separate it from the background).
The novelization of TESB (before the ISD "collision") wrote that the closing two ISDs were nearly within range and those ships did not fire. So, at least in that occassion they did not open fire untill they would be within range.

However I have to rethink my "retreating tactics". Maybe it does not work at all or maybe it only requires a more complex maneuver than just a straight retreating.

[Kazuaki Shimazaki]

I didn't write it, so I apologize, but I ment that it tried to get out of range. (My retreating tactics, you know.) So, you canot stay in place and just pitching down. You most follow or leave it.

You can "slide" under it. I've tried to explain this to you. You can follow it and shoot at it at the same time, though admittedly not as capably as a bowchaser design. It is kind of the same way a conventionally laid out battleship maneuvers to get all its guns on a fleeing target only that we pitch instead of yaw/turn.

See my theoretical main weapon arrangement. This compromise is unneeded. I call an unneeded compromise as a design flaw.

How do you KNOW it is un-needed? Besides If you don't care about potential problems (racking it up to them not thinking about it,) then the centerline is even better. Whether you divide into dorsal or ventral sets, a centerline arrangement (space the turrets out so they can superfire using the natural slope without building a extra hull extension) allows 100% forward, 100% port and 100% to starboard. If you put them all dorsal or ventral , you get 100% dorsal or ventral as well.

If you think that way, therefore, your structure is also flawed.

Yes. But unless we know this line it is an unneeded compromise. We can also assume that the designers simply did not face the problem since there were no real opposition when the ISD II was designed.

It wasn't like they didn't face this problem. They did have relatively ventral heavy guns and superfiring turrets in the ISD-I, right? So they did try those things. They decided they were so useless or even disadvantageous that they actively TOOK THEM OFF in exchange for something else. The typical procedure is to assume reasonable competence, so that actions not taken (though they LOOK technically feasible at first glance) can imply actions not feasible.

If we assume competence, obviously the line is somewhere between Triple 10m Gun Turrets and Octuple 14m Gun Turrets.

Simply no. The turret remains the same, only the hull under te turret is elevated. Watch the support structure (that actually holds the guns) of the main guns of the ISD II. They can handle the strain caused by the guns and they are very small. Saying that handling this strain could pose any problem to a hull elevation under the turret is beyond me.

The support structure sits on top of a much larger turret structure, which in turn apparently sits on other support stuff that can't even make it in the turret. If any of these don't work in the new superfiring turret... then the turret cannot be used.

For a "largely sitting and shooting each other" scenario there is only minimal difference between the two designs. This modified is slightly better due to the smaller target profile required for concentrated fire.

You lose out in the parallel battle, which is also quite popular and a tactic mentioned in the Rebel Sourcebook. You can bow-chase with 8 guns, but your parallel is only 4 guns (pick dorsal, ventral, port or starboard, but you are only getting 4 guns.) Wins and loses...

It was a long range situation where the distance was important due to the range of the guns. Even with 1% of difference it will be out of range soon. You canot pursue it slowly and cautiously.

We should consider one thing: Can the ISD accelerate directly toward 15 degrees off-axis or not? I say not or only in an extremely limited manner (one or two percent of their forward thrust). It is based on mechanics, and that the ISD does not have large enough (visible) thrusters to compensate the rotation. It is harmonious with the "collision" in TESB.

There is no need to accelerate directly forward with a 15 degree off-axis thrust (though of course the capability would be welcome.) My scenarios try to use certanties as much as possible. So I merely used aerodynamic like turns, probably with that etheric rudder stuff.

If things really are that marginal as to depend on a few percent here and there, well then there are lots of factors that become more significant.

As for your surround my bulb tactic:
Suffice it to say that you need five SURVIVING ships to gurantee success. You need one to block my hangar bay and prevent me from accelerating. You need another one behind me, behind my bulb, to prevent me from decelerating. You need a third and a fourth to block my attempt to turn. And a fifth to prevent me from pitching up and escaping.

Your five ships will require very good formation control, despite no doubt having come under fire and very possibly taking damage. And even after you do this, I could INTENTIONALLY ram my bulb (which is probably the strongest part of the ship) against the ship directly forward of it (right into its engines, a more vulnerable part)

You'll need brave volunteers too. Figure 1 or 2 would get blown up during the approach. HTTE establishes my tractors can effectively hold onto anything up to an Assault Frigate, so another 1 or 2 would get tractored and force lifted up my centerline to get blasted. After losing several ships, I doubt yours would be very keen for a fight. You could run. Maybe I couldn't catch all of you in the end, but you are still dead. Plus I can make defensive rolls and turns to make your "docking precision" task more difficult.

A problem, but not a vital, absolutely killer flaw.