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.
Thinksmarkedly wrote:I might agree but that's irrelevant because it's not two thirds of the volume. From the drawings we've seen, the three drive rings together occupy at a third of the missile's volume. So shedding two of them would reduce your volume by a quarter or a fifth.
That calculation might be a bit premature. The volume occupied by the drive rings does not necessarily indicate the volume of the missile that would be rendered inert when a particular drive ring is spent. As a matter of fact, don't stages (even in multi-drive missiles) have differently rated burn times? Anyway, I would hesitate associating and guestimating the inert volume of a missile based on the volume occupied by its drive ring.
As an example that is included solely to accompany my thoughts.
Five-Segment Solid Rocket Booster The SLS booster is the largest, most powerful solid propel-lant booster that will ever fly. Standing 17 stories tall and burning approximately six tons of propellant every second, each booster generates more thrust than 14 four-engine jumbo commercial airliners. Together, the SLS twin boosters provide more than 75 percent of the total SLS thrust at launch.
If our very own booster rockets burn that much fuel every second then surely the infrastructure associated with the far longer burns of HV missiles (capacitors and accompanying electronics) occupy a formidable volume. Multidrive missiles got much longer than the volume occupied by the drive rings over their long history of development. No?
But yeah, I might be a tad bit overly optimistic about a missile possibly shedding two thirds of its volume. But I've always been an open-minded sort. And as stated upstream, I will remain optimistic about the volume of a missile that might be shed if some entity were to
specifically design its missiles to separate after a spent stage. Capacitors, associated electronics and other gizmos just might be as volume intensive as the chemical fuel aboard our very own booster rockets since the range and burn time of the missiles in the HV are far longer. So who knows. I shall remain opti– …
enthusiastically optimistic.
What
is the burn time of the various stages of multistage missiles? Anyone know?
The missile does drop its wedge just before firing, but I am not sure targeting is not completed beforehand. I would wager targeting is already completed.
Thinksmarkedly wrote:We don't know what affects the rotation rate of a wedge and whether any particular direction has a higher rate than the others. We only know that it's faster for a ship to rotate using its wedge than using thrusters and Newtonian Physics. If the missile performs its attack rotation using the wedge, it's possible the missile's volume is completely irrelevant.
Indeed, but if the volume has been significantly reduced then a missile might be able to sufficiently rotate without a wedge.
Thinksmarkedly wrote:If it has to aim after dropping the wedge, then indeed the volume matters because then it's just pure Newton. If you remove mass, then you have less inertia to counteract. On the other hand, Archimedes would like to have a word about leverage.
And then we go back into unknown Physics when we examine that the x-ray lasers are focused by gravitic mechanisms. It's virtual lens, not a physical medium. So what's to say you can't change its "optics" to bend the beam in the direction you want it to go anyway?
Ditto on Archimedes and his word about leverage. One would only have to remember the gyroscopes of ones childhood and how difficult it was to roll the gyroscopes against its axis of spin.
If it currently aims before dropping the wedge then shedding volume certainly won't hurt it. If it currently aims after dropping the wedge then shedding significant volume should help it tremendously.
But the whole object of this exercise is for the missile to surprise, evade and befuddle point defense. Again, I suggest that the missile might be able to drop the wedge before it normally does so that point defense no longer has a huge beacon to assist in targeting the missile body. How much time beforehand the missile should drop its wedge for this tactic to work has to be worked out by the design team just like Hemphill had to determine the correct moment her missiles had to dive to evade the Triple Ripple.
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.
Thinksmarkedly wrote: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.
Rotation and roll are different, right? Why would rotating lose lock if the sensor is located at the nose of the missile? Indeed, I thought the entire nose
is the sensor? No? In which case rotating would not cause the missile to lose lock. Rolling would. I am not certain why a missile would even need to rotate (spin).
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).
Semantics really matter here and I hope I am not confusing it. But that is not what we have information on. “Rolling” a ship is
not rotating around the long axis. Unless ‘around’ the long axis is not the same as ‘about’ the long axis. For clarity, perhaps rotating should be referred to as spinning. Like a figure skater.
Jonathan_S wrote: 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).
I think we have another data point on pitch rates. Remember the demonstration launch Honor provided which had the missiles bearing down on a Peep ship only to pull up short then pirhouette and fire at absolutely nothing? (Actually I think the wedge was specifically targeted.) That gives a lot clearer data point on the performance and range of pitch rates.
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The artist formerly known as cthia.
Now I can talk in the third person.
