runsforcelery wrote:Jonathan_S wrote:Though at those ranges, in fact any pre-Apollo effective range) even with normal Mk23s they should already be using at least the 1st drive at it's max setting (High-Low-Low drive profile) - but for some reason we never see them doing so in the books.
Quickest 3-drive profile by range is:
0 - 17 MKm - High-High-High (14-17 requires coast phase)
17 - 41 MKm - High-High-Low (33-41 requires coast phase)
41 - 70 MKm - High-Low-Low (50-70 requires coast phase)
70+ MkM - Low-Low-Low (65+ requires coast phase)
At 50 MKm the HLL profile gets the missile on target 52.4 seconds sooner and with about 2% higher terminal velocity compared to what we see used in the books with all 3 drives at 50% power.
(Somewhere buried on the board is a whole thread I created showing this in detail with graphs)
It is true that mixing
acceleration settings would make for more flexible tactics. Unfortunately, because of
the nature of
the "splitter plate" technology used in
the current generation MDM,
you can't set different acceleration rates on
the sequenced drive nodes.
The "splitter plate" has to be adjusted and paired to
the selected
acceleration rate (effectively, "
set" to damp
the molecular distortion of a single power level) across all 3 sets of nodes. (I'm almost sure that I commented on this either in one of
the books or in a post online quite some time ago.) This is something that R&D is still working on but has not yet solved.
So
the different combinations of "high" and "low"
acceleration which are being proposed are not workable
at this time. They may
become possible, but right now they aren't.
Ah. Thank
you. If
you'd said that before I'd missed (or forgotten it).
I may have been mislead by Honor's correction to White Haven in
the Harrington Library back in In Enemy Hands, or Honor might have been thinking
the R&D breakthrough of mixed
drive settings would happen immenently.
In Enemy Hands wrote:"Certainly she came up with the concept, but R&D took it and ran with it. We're talking about a 'multistage' missile—one with three separate drives, which will give us a degree of tactical flexibility no previous navy could even dream of! We can preprogram the drives to come on-line with any timing and at any power setting we wish! Simply programming them to activate in immediate succession at maximum power would give us a hundred and eighty seconds of powered flight . . . and a powered attack range from rest of over fourteen and a half million kilometers with a terminal velocity of point-five-four cee. Or we can drop the drives' power settings to forty-six thousand gees and get five times the endurance—and a maximum powered missile envelope of over sixty-five million klicks with a terminal velocity of point-eight-one light-speed. That's a range of three-point-six light-minutes, and we can get even more than that if we use one or two 'stages' to accelerate the weapon, let it ride a ballistic course to a preprogrammed attack range, and then bring up the final 'stage' for terminal attack maneuvers at a full ninety-two thousand gravities.
I'd thought Honor was talking of using 2 drives at half power and
the 3rd at full - but rereading I see she doesn't actually say that. She should have been speaking of 2 drives a full, a coast, and
the final
drive also at full. Though specifically mentioning
the drive setting of just
the final one doesn't seem to imply that.
But still, like I said, she could have been anticipating that that capability would be available once they were build and been disappointed it turned out to be harder than expected.
Though
the Mantie R&D must have made
some progress on it since
the "baffle" splitter plate can handle protecting
the CM derived 4th stage on
the new system defense Mk23s from
the 3 normal drives. (But they might be able to tune for that since
you'd expect, and possible hardwire, those missiles to be tuned for max range with half power on all 3 main drives and then
the final
drive has to be hardwired (since
you did say elsewhere that one of
the tradeoffs of
the overpowered CM style drives is that they
can't be dialed back to lower
acceleration)
runsforcelery wrote:What I hadn't considered, because for so many decades missile acceleration rates were basically hardwired by the various navies at either full acceleration or half acceleration, would be the possibility of dialing in an acceleration rate somewhere between those 2 extremes to max out performance over a given range. I'd have to play around with the numbers a bit, but it seems likely that in certain range brackets that would buy you a bit more time before the enemy's first salvo launched in reply could reach you. I'm inclined to think the window would probably be fairly short, however, and it wouldn't have any impact on the intervals between follow-up salvos, since that interval would be governed by the speed at which pods can be rolled. It might mean a slight advantage in closing speeds, getting the missiles through the defense of envelope a bit faster, but at first glance, I think that would probably be about it.
Fairly early on, probable in
the appendix to Short Victorious War or
the essay in Worlds of Honor it did mention that
the Manties didn't hardware their missile settings, but that going lower than 50% gave more run time but resulting in less range and lower terminal velocity (so it must have been something of a local maximum).
I'd just assumed from that, and
the fact that nobody every used an intermediate setting, that 100% power was another local maximum and
the area between them
the drive life fell off too quickly to usually be beneficial. That at, say, 75%
drive power,
you'd have at most only a few percent more run=time than at 100% so
you'd be worse off picking that because
the extra seconds couldn't make up for
the reduced
acceleration rate.
But that was just head cannon.
But there have always been some gaps in missile
drive tech that looked odd from
the outside, like why nobody had been able (or at least hadn't been willing to pay whatever trade-off was involved) to combine dual or multi-
drive missile's baffle/splutter with
the extended runtime of extended range missiles. A Mk16+ built around a pair of just 75|225 second drives would have a 50% better reach - making 45 MKm max powered range.
Arguably in
the capacitor powered era a 2-
drive ERM based DDM would have let
you build a smaller capital missile that had nearly as much
usable range as
the Mk41s they actually build - giving
you the ability to put more in your magazines or design smaller pods (hopefully allowing
you to carry more of them)
But there's probably some tech reason that hasn't needed to be shared with us on why that's not actually a practical approach.