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ThinksMarkedly wrote:

penny wrote:True. True. But the principle of compensation should be the same regardless of the nuts and bolts utilized to achieve it. If not, then therein lies the entry point that exists to exploit the difference. Tum te tum per the MAlign.

We don't know that they are the same. We don't know what magic for compensation works for missiles. All we know is that it's different from the standalone compensators for ships.

But also, we don't know what the compensated volume of the missile is in the first place. Maybe the minimum practical volume of compensation is already much larger than the missile itself, so making it smaller or less massive wouldn't lead to a reduction in the compensated volume, which in turn wouldn't lead to an increase in acceleration. The missile volume isn't limited by the wedge's compensated volume: it's instead limited by the size of the tubes it's fired from and the pods it's stored in. And since it's stored and fired in full size, the size of the missile after dropping a stage is completely irrelevant.

Jonathan_S wrote:The RMN MDMs seem to have the same acceleration as their SDMs; so the larger size doesn't seem to have slowed them any.

penny wrote:Which might be the result of a larger volume available to house the built-in compensator.

It's practically exactly the same, so it's highly unlikely that two different compensators on two different missile bodies achieved that entirely by coincidence.

However, it could be intentional because having time-on-target solutions with other missiles is a useful thing to have.

But all of that could be a function of the static nature of a compensator whose compensation effect cannot change. If the volume of the compensated area magically changes on the fly then it seems as if the compensation effect would increase, allowing for a higher drive setting. IOW, the static nature of the existing setup might be a function of the static compensation effect.

It doesn't look like that's how impellers work. The impeller is locked to a specific acceleration setting, regardless of what is being compensated. Though it's not impossible that changing one makes the other change due to how the equations work.

I see your point and it is well taken. Actually I realized from the onset that the extreme difference in the volume occupied by our chemically powered rockets wouldn't equally transfer to the equation. Our rocket fuel is just so volume intensive. But losing even a small volume of the missile should equate to a potentially significant increase in performance.

Or, conversely, an even smaller change in performance. Suppose that a change in volume results results in the square of that changing in acceleration. That means a 1% change in volume results in a 0.01% change in performance. That's actually rounding error.

Can anyone post the statements made by David about a missile's compensator?

penny wrote:Anyway, the suggestion is simply a theory of concept. Something that may be worth investigating by open-minded navies. And do consider that a much larger percentage of a missile's body might be discarded if some navy were to specifically design its missiles for this tactic. We already know the Cataphracts may be a prime candidate.

I think it was Thinksmarkedly who first pointed out that a smaller missile body could roll much faster. Certainly if a warship can roll 45 degrees in 12 seconds a missile should be able to roll 180 degrees in one second, even before shedding ⅔ of its missile body. Yeah, I'm banking on two-thirds of a missile body being shed.

A smaller missile body might also improve down the throat shots.

Question. First, for my own review, why can't a missile's wedge be completely closed on the nose?

penny wrote:Can anyone post the statements made by David about a missile's compensator?

I've been failing at finding it. I really thought I rembered him saying that they had their own compensating mechanism; different than a ship's. But to date my attempts to find that in my notes, the archive of the infodump site, or the books themselves has failed.

penny wrote:Question. First, for my own review, why can't a missile's wedge be completely closed on the nose?

Presumably for the same reason a ship's can't. That's not how wedge geometry works

On Basilisk Station wrote:The impeller drive created a pair of stressed gravity bands above and below a ship—a wedge, open at both ends, though the forward edge was far deeper than the after one—capable in theory of instant acceleration to light speed. Of course, that kind of acceleration would turn any crew to gory goo; even with modern inertial compensators

It's not clear you can form those gravity bands into any shapes other than inclined wedges (or for Alpha nodes - enormous discs). And if you could it wouldn't be able to provide any acceleration. (Plus the missile would have a hell of a time seeing through the wedge well enough to maintain sensor lock on its target)

Even if you close the nose off with a sidewall (which missile's don't use) it kills your ability to accelerate

Echoes of Honor wrote:"As we all know, it's impossible to close the bow or stern aspect of an impeller wedge with a sidewall, right?" Heads nodded once again. "And why is that, Lieutenant Takahashi?" she asked genially.
[...]
"Because cutting off the stress bands' n-space pocket with a closed wedge prevents you from accelerating, decelerating, or using the wedge to change heading, Ma'am," he replied. "If you want the math—?"
"No, that's all right, Lieutenant," she said. "But suppose you don't want to accelerate or decelerate? Couldn't you generate a 'bow' sidewall then?"

penny wrote:I think it was Thinksmarkedly who first pointed out that a smaller missile body could roll much faster. Certainly if a warship can roll 45 degrees in 12 seconds a missile should be able to roll 180 degrees in one second, even before shedding ⅔ of its missile body. Yeah, I'm banking on two-thirds of a missile body being shed.

A smaller missile body might also improve down the throat shots.

I don't think it matters. I had a very different answer while writing this reply, but after some calculations I came to the exact opposite of my premise. I was going to say that I didn't think missiles rotated fast because rotation rates appear to be correlated less-than-linearly with mass and therefore a decrease in mass would imply negligible improvement in rotation rate. I still think the decrease in mass is not going to make a meaningful difference when we know the rings are a small portion in the back of the missile, but it's also irrelevant.

Here's what I ended up realising: I do think missiles rotate plenty fast already.

By the time we're talking about MDMs, the missiles are screaming past their target ships at better than 0.8c. If the target's throat (the largest aspect) is a mere 190 km wide, the missile will overfly it in a mere 0.8ms.

We also know that missiles don't enter PDLC engagement range with their own wedges interposed -- we know that because PDLCs exist in the first place and can take out missiles, even MDMs. Obviously that's for plot reasons, but in-universe that's technically explained by their being too dumb to maintain a target lock over long distances and a long period of time.

Therefore, improving the rotation rate doesn't help the missile. The problem is not how fast it can rotate to track the ship it's attacking. The problem is that it can't begin rotating in the first place because doing so makes it lose the target lock. They appear to rotate plenty fast already -- if we assume the PDLC engagement range is 240,000 km, at 0.8c they'll reach the target ship in just 1 second. And we know they can rotate that fast or faster, because because missiles can actually shoot ships that have interposed wedges (even SLN missiles can, just not very effectively).

That's not to say there would be no gains. Yes, improving the rotation rate probably improves the ability of the missile to better target the ship it's attacking. I just don't think removing two stages of rings is going to make that much of a difference in performance. Every little bit might help, but I´d be astonished if this resulted in even 10% improvement.

ThinksMarkedly wrote:Therefore, improving the rotation rate doesn't help the missile. The problem is not how fast it can rotate to track the ship it's attacking. The problem is that it can't begin rotating in the first place because doing so makes it lose the target lock. They appear to rotate plenty fast already -- if we assume the PDLC engagement range is 240,000 km, at 0.8c they'll reach the target ship in just 1 second. And we know they can rotate that fast or faster, because because missiles can actually shoot ships that have interposed wedges (even SLN missiles can, just not very effectively).

At least at the beginning of the series the PDLC range is given (in a diagram in Jaynes) as 100,000 km. So they've even less time to engage.

I can't recall anything specific about their range increasing during the series -- but certainly against faster missiles it would be beneficial to boost it. (Assuming that doing so didn't entail tradeoffs that more than offset the benefit; such as reducing the number of emitters and thus number of shots against each missile; or reducing the number of mounts a ship could carry)

Jonathan_S wrote:At least at the beginning of the series the PDLC range is given (in a diagram in Jaynes) as 100,000 km. So they've even less time to engage.

I can't recall anything specific about their range increasing during the series -- but certainly against faster missiles it would be beneficial to boost it. (Assuming that doing so didn't entail tradeoffs that more than offset the benefit; such as reducing the number of emitters and thus number of shots against each missile; or reducing the number of mounts a ship could carry)

I don't think it did. I just used a round value that definitely overestimated the time to prove the point. At 120,000 km, the missile would cross from PDLC range to ship in half a second. And if they can themselves fire from 50,000 km, it means they can rotate in the 70,000 km that separates that, though of course that only applies if the angles are really favourable.

ThinksMarkedly wrote:

Jonathan_S wrote:At least at the beginning of the series the PDLC range is given (in a diagram in Jaynes) as 100,000 km. So they've even less time to engage.

I can't recall anything specific about their range increasing during the series -- but certainly against faster missiles it would be beneficial to boost it. (Assuming that doing so didn't entail tradeoffs that more than offset the benefit; such as reducing the number of emitters and thus number of shots against each missile; or reducing the number of mounts a ship could carry)

I don't think it did. I just used a round value that definitely overestimated the time to prove the point. At 120,000 km, the missile would cross from PDLC range to ship in half a second. And if they can themselves fire from 50,000 km, it means they can rotate in the 70,000 km that separates that, though of course that only applies if the angles are really favourable.

Fair, fair.

And of course the rotation value we have the best information on at various tonnages is roll (rotating around the ship's long axis) which is of limited use in avoiding PDLC fire as it doesn't change where the nose is pointing (likely right at the target). Though a roll would keep moving the vulnerable sides of the wedge and make it a bit harder for ships further away from the target to make PDLC hits. (Roll is a more useful metric for ships as they tend to fight nearly broadside on, so a roll will interpose the wedge or can bring the previously unengaged broadside to bear)

But for a missile trying to interpose its wedge against PDLCs the important metric would seem to be its rate of pitch (as yaw wouldn't alter which ships can hit it, as it leave the vulnerable gap between the wedges unchanged in orientation). And we've very little info on pitch rates for ships, and I don't think any on missiles (beyond knowing that the RMN was able to program a pitch maneuver into their MDMs to blunt the effect of the Triple-Ripple as an anti-missile tactic - but that doesn't tell us much since that was so much further out and could have been done with a fairly slow pitch rate).

ThinksMarkedly wrote:

Jonathan_S wrote:At least at the beginning of the series the PDLC range is given (in a diagram in Jaynes) as 100,000 km. So they've even less time to engage.

I can't recall anything specific about their range increasing during the series -- but certainly against faster missiles it would be beneficial to boost it. (Assuming that doing so didn't entail tradeoffs that more than offset the benefit; such as reducing the number of emitters and thus number of shots against each missile; or reducing the number of mounts a ship could carry)

I don't think it did. I just used a round value that definitely overestimated the time to prove the point. At 120,000 km, the missile would cross from PDLC range to ship in half a second. And if they can themselves fire from 50,000 km, it means they can rotate in the 70,000 km that separates that, though of course that only applies if the angles are really favourable.

Jonathan_S wrote:Fair, fair.

And of course the rotation value we have the best information on at various tonnages is roll (rotating around the ship's long axis) which is of limited use in avoiding PDLC fire as it doesn't change where the nose is pointing (likely right at the target). Though a roll would keep moving the vulnerable sides of the wedge and make it a bit harder for ships further away from the target to make PDLC hits. (Roll is a more useful metric for ships as they tend to fight nearly broadside on, so a roll will interpose the wedge or can bring the previously unengaged broadside to bear)

But for a missile trying to interpose its wedge against PDLCs the important metric would seem to be its rate of pitch (as yaw wouldn't alter which ships can hit it, as it leave the vulnerable gap between the wedges unchanged in orientation). And we've very little info on pitch rates for ships, and I don't think any on missiles (beyond knowing that the RMN was able to program a pitch maneuver into their MDMs to blunt the effect of the Triple-Ripple as an anti-missile tactic - but that doesn't tell us much since that was so much further out and could have been done with a fairly slow pitch rate).

Even if so -- and I shall guard my vote for confirmation of your point -- a missile that has managed to shed two thirds of its volume should manage a much faster pitch or yaw. That also drives my point that up the kilt shots should be more successful if I am correct that up the kilt shots are opportunistic maneuvers made when a missile sees an opportunity. But just a small bit of increased quickness and responsiveness "at the helm" just might make the missile a lot more effective and deadly.

penny wrote:Even if so -- and I shall guard my vote for confirmation of your point -- a missile that has managed to shed two thirds of its volume should manage a much faster pitch or yaw. That also drives my point that up the kilt shots should be more successful if I am correct that up the kilt shots are opportunistic maneuvers made when a missile sees an opportunity. But just a small bit of increased quickness and responsiveness "at the helm" just might make the missile a lot more effective and deadly.

I think you'd need more than just a little more quickness to routinely make up the kilt shots.

If the ship is rolled behind it's wedge then yes, it'd make sense to angle for an up the kilt or down the throat shot -- as opposed to attacking the broadside. You've a better chance of only having armor, rather than a sidewall, in the way - and against a podlayer an up the kilt shot has a chance to disable at least a pod bay door and might give you a golden BB that wrecks the stored pods. And regardless of which of the four sides you attack you've got to fly around the edge of the wedge and then make a snap shot before you fly clear past the other wedge. (Of course against RMN ships they do have bow/stern walls; so unless they're actively accelerating they've likely got either the bow or the stern covered by a full wall -- so as you crest the wedge and finally see you'll find out whether you'll have a chance at a sidewall-less attack of not.

And of course if the enemy is has their stern to you (running directly away or decelerating towards you) then an up the kilt shot is the easiest one to make.

But if the ship is broadside on and engaging the incoming fire with its PDLCs then you've a much lower chance of making it into a spot where you can make the up the kilt shot.



To pull it off you need to fire from within a narrow slot behind the ship. The rear opening of an SD's wedge is only 40 km high; and the sidewalls extend along it; leaving a gap only 20 km wide between them. So for a proper up the kilt shot you need to fire while you can see the ship's stern down that 20x40 km shaft from 30-50,000 km away. And then hope they don't have their sternwall up. (And even then part of that slot's angles might be blocked by a buckler wall; which can be up while accelerating or while a full wall is active at the other end of the ship)

But let's say you've got a warhead with the same 50,000 km standoff of the RMN. If you same in straight at the ship's broadside you'd only have to cover 50,000 km of PDLC fire to reach your firing range. But to keep going astern of the ship to reach that up the kilt zone -- that approach geometry forces you to remain exposed to PDLCs for up to 73% longer! So it's very much a risk/reward scenario. If you get there you might hurt the ship more -- but your chances of charging that much longer through the point-defense envelope are much lower.

It's going to take more than a bit more maneuverability to offset a 73% longer exposure to defensive fire. (And if coming in from astern, or against a target that's rolled behind its wedge, you shouldn't need extra maneuverability to try for an up the kilt shot)

If you're rolling a ship, you add yet another component to the firing solution (including leading the target) to hit a missile with a PDLC. That's one of the things that all the sensors and targeting computers are for- figure out where the incoming weapons are and put your countermeasure to intercept in in X amount of time from when you fire them.

And why do you think the missiles are rolling/spinning to avoid counter measures? If it's a CM that it is trying to defeat, having the CM and the shipkiller's wedges touch is going to destroy both of them.