"Obsolete SDs" Waste not...

MaxxQ wrote:As far as I know, it's just a basic nuclear detonation, with the added effects of the grav lenses focusing all the X-Ray energy forward towards the laserheads. I'm assuming (although I'm sure someone here will point out that I'm wrong) that the grav lenses would also focus any OTHER detonation effects in that general direction as well. OTOH, maybe the grav lenses are tuned to only focus X-Rays... <shrug>

x-rays should outpace whatever physical debris from the bomb exits, particularly as a grav tamped bomb there isn't the need for a heavy radiation case in the direction of the laser heads. You could literally have just a plastic dust cover on top of the bomb electronics. So most of what debris will get blown free should be extremely rapidly turned into plasma by the radiation front and energized enough that it is effective transparent if I kind of remember how this works.

kzt wrote:

MaxxQ wrote:As far as I know, it's just a basic nuclear detonation, with the added effects of the grav lenses focusing all the X-Ray energy forward towards the laserheads. I'm assuming (although I'm sure someone here will point out that I'm wrong) that the grav lenses would also focus any OTHER detonation effects in that general direction as well. OTOH, maybe the grav lenses are tuned to only focus X-Rays... <shrug>

x-rays should outpace whatever physical debris from the bomb exits, particularly as a grav tamped bomb there isn't the need for a heavy radiation case in the direction of the laser heads. You could literally have just a plastic dust cover on top of the bomb electronics. So most of what debris will get blown free should be extremely rapidly turned into plasma by the radiation front and energized enough that it is effective transparent if I kind of remember how this works.

Yup... the x-rays outpacing everything else is why these "work" the way they do. As for the rest, well, if you say so...

kzt wrote:

Joat42 wrote:You don't re-orient the missile, you eject the lasing rods so they end up at the optimum position to hit a target before the "nuke" goes off, this takes a very short time. At least that's how I understand how bomb pumped lasers are supposed to work in a combat effective way.

And you get something of a blast effect from the vaporized missile materials although the area of effect is minuscule compared to the distances involved in space battles.

You still have the particle wave-front from the nuclear explosion and it's secondary effects but it also has to follow the inverse-square law.

No, you want the coarse aiming done by the missile. For one reason the grav lens used needs to be between the bomb and the laser heads. But there are more.

Consider the case of a missile targeting a rolled ship. You are going to pass 30,000 km away from the target. With the missile aimed roughly where it expects the target to be the laser heads need to move a fixed distance at a fixed velocity and fixed vector to reach firing position, so you can easily determine when that will be and provide appropriate vibration dampening etc.

If the missile is aimed 90 degrees to the target you need to have the laser rods all get to exactly the right spot at exactly the right time. Each of them needs to spin, then travel a different distance, at a different vector and using different amounts of thrust to get there. So you now require a much more complex engine. And since you are having them turn about 90 degrees and the actual laser rod is 5 meters long and about 0.06 millimeters in diameter, vibration is probably going to be a lot bigger problem.

I would think that with grav tech you can move the rods in any way you want in a very short time span without any problems.

It's not the predetonation size that matters, it's the mass.

For a 25MT yield you have to _fuse_ 300-800kg of fuel - the range depends on the reaction chosen, and thus on actual reactant mass and how much energy is lost to neutrinos. Depending, again, on how insanely optimistic you are about efficiency, that means 2-20 tonnes of fuel alone, plus machinery. Since this is science fiction, we can assume unphysical masses for both fuel and the grav-pinch system, but we do need to add mass for whatever material is included to get high x-ray luminosity, and one thing we do know about handwavium is that it has to be quite dense. That leads to a WAG of 6-10T for the mass of the warhead. The assumption [don't you love that word - if any of these numbers are within 50% I'll be thrilled] of uniform expansion actually gives the debris a density in the range of air at 150 meters, although, since it should really be expanding as a shell, the final number will be as much as 100x higher. Temperature, OTOH, will be ~100K. Possible even a lot less, since the radiative cooling that produces the X-ray flash invalidates the adiabatic approximation - and since I don't have the software to model this you know where I had to get that last number from

drinksmuchcoffee wrote:

Louis R wrote:There is if you're close enough to the warhead that the fireball still contains sufficiently dense material at sufficiently high temperature.

Without knowing what BuNine is postulating for explosion conditions, I can't determine that, but a bit of playing around using adiabatic simplifications leads to some skepticism, to be honest.

If your warhead is a sphere 2m in diameter, at 100m from the detonation the density would be one one-millionth of the density of your warhead. So for all practical purposes, unless you are extremely close to the detonation (on the order of 10-20 meters or less), there would be no blast effects.

Question, how would one of the best of the SLN SDs (with Halo, Fleet 2000, etc...) compare to HMS Hercules (no pods, just on board weapons)?

Mikeo wrote:Question, how would one of the best of the SLN SDs (with Halo, Fleet 2000, etc...) compare to HMS Hercules (no pods, just on board weapons)?

Here's my lengthier than I originally realized take on this; using a Vega-class SD, which has a couple extra tubes per broadside over the old Scientist Class.

I don't think we know her exact tonnage, but a bit bigger and slower than the 6.8 mton Scientist's normal 432.0 gees.

Compare that to Samothrace-class HMS Hercules 7.25 mtons; at launch she'd have been capable of only 416.6 gees, but if we're allowed to assume she got a mild refit around 1914 PD she should be capable of at least 487 gees flat out. Now of course most navies restrict themselves to no more than 80% of that max accel - but Manticore has realized, from war experience, that compensators have become more reliable under heavy load and their new fleet max is 90%. So bigger and faster than the SLN ship.

Lets compare missile broadsides.
Vega: 34[*] - Samothrace: 28
But remember thanks to Aegis the Vega needs to devote several of these to CM canisters, not offensive missiles. Also based off the BC info we have the Manticoran missile tubes should cycle at least twice as quickly; so this is actually advantage Manticore.

And CM tubes:
Vega: 16[*]
Samothrace: 18
Again these should be faster cycling for the RMN

And PDLC:
Vega: 32[*]
Samothrace: 26
You can see the bias towards PDLC over CM here for the SLN - but I've got a note that somewhere it was mentioned that each PDLC on an RMN BC(P) is superior to that of a SLN SD - so I'm not sure how these stack up one on one to Hercules. Call it a modest advantage SLN, if not just a push.

As for missiles, on the drives the SLN actually has a slight edge. Their Trebucht should be capable of 47,600 gees for 180 seconds = 7,556,976 km range
And the RMN SDM is only good for 46,000 gees for 180 seconds = 7,302,960 km range
But given Manticoe's real world warfighting experience I'd give them a solid edge in ECM and ECCM even with the old capacitor powered single-drive missiles. So despite a marginally slower terminal velocity their missiles are probably harder to hit and less likely to be fooled/confused by decoys or jamming.

And I'd guess the old launchers on the Hercules might well be able to accept the Mk30 CMs from the ceasefire period - that would give Manticore a major edge in CM range.
SLN: presumably around the 1.5 million km of the pre-war CMs (which incidentally is really also all we've seen from Haven)
RMN Mk30: 130,000 gees for 60 seconds = 2,293,200 km range.

I'll ignore energy range combat, though that's what the Vega is really optimized for since it's unlikely Hercules would close without badly crippling the Vega first.

Things are harder to judge on the decoy front - does Hercules have her original tethered only decoys? Or have they been swapped for some of the Buttercup era micro-fusion powered Ghost Rider decoys that were so effective against Haven during their abortive offensive just before Buttercup was unleashed?
We know the Halo hardware the SLN has is pretty decent, but apparently it's software blows and you have to assume that Hercules has gotten the latest SW routines to use with whatever ECM hardware she has - as that's the easiest part to keep current. So at a guess Hercules has a solid edge there as well.

Armor is probably a wash as a Samothrace is too old to have the continuously grown, laser-head optimized, armor that debuted nearly 50 years later on the Star Knight CA - so her armor is probably much like the SLN's.

But Hercules probably does have Ghost Rider recon drones off in the corner of her boat bays, replacing the far more limited capacitor powered drones she's have launched with. That would give her a major edge in the recon battle, and let them near real-time back the defensive ECM and tactics of the Vega; letting her give more current information to her attack missiles.

Basically I'd say Hercules, no pods, in a one-on-one fight with a current Vega armed with the SLN's Trebuchet missile probably has an 85+% chance of battering the Vega into surrender. I'd even give her a near even chance against a pair of them. The combination of battle tested ECM routines, more mass to absorb damage, better recon, more experience at combat damage control, significantly faster cycle times on all launchers, better accel, and longer ranged CMs just adds up to too much of an advantage - even without the newest and best RMN gadgets.
OTOH golden BBs exist, and there's always a risk that a lucky hit will knock out your wedge -- that would upset a fight in a hurry. And unlike the newest designs Hercules can't engage a Vega or Scientist without closing into their own missile range; so you do have to factor in the chance of a few lucky hits upsetting the favorite.


Now if the SLN was carrying Cataphract-Bs in their tubes that'd be an interesting twist. Those substantially outrange Hercules' missiles - yet carry a much lighter warhead. I believe Hercules would have the compensator upgrade to let it chase down the Vega - but assume normal fleet max accels she'd have only a 100g accel advantage; so just considering the Cataphract's powered range she'd have to survive up to 75 minutes of unreturned fire (actually worse because that would be a stern chase which shortens her effective missile range. OTOH in a stern chase like that the Vega could only use it's few stern tubes so you're not taking much fire per salvo - but you wouldn't have the control links for offboard firing like the new ships; so you can only defend with your forward chase mounts...)
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[*]These numbers are based off the Scientist-class, but we're told a Vega is just stretched with a couple more missile tubes per broadside; so I gave +2 for that and same for the defensive.

Whose to say that Hercules wasn't given some weapons upgrades like ERDM or the equivalent of a Mk 16 Mod G warhead upgrade for her Mk 13 capital missiles. Also for Hercules you could add better long range targeting.

saber964 wrote:Whose to say that Hercules wasn't given some weapons upgrades like ERDM or the equivalent of a Mk 16 Mod G warhead upgrade for her Mk 13 capital missiles. Also for Hercules you could add better long range targeting.

A Mod G style warhead upgrade might well be an easy upgrade. But Manticore never designed a capital ship grade ERM for the simple reason that they already had the far more capable 3-drive MDMs for that.

Now technologically there's no reason you couldn't build a heavy ERM - but it wouldn't fit in Hercules' missile tubes. There's been no significant breakthrough in capacitor storage density - so the extra 45 - 90 seconds of 1/2 power flight time require 25-50% more capacitors to power. (And a micro-fusion reactor is bigger even than that; it and it's fuel is more like twice the volume of a single drive's capacitors - so it doesn't save you much space until you're up to 3 drives; but the extra power is a nice to have for dual drives. Plus of course you have to install different launchers and additional cofferdam armoring if you switch to microfusion powered missiles; so that's an even bigger refit job that adding oversized ERM tubes)

There isn't free space in the missile so you need a bigger missile to hold them. That's why the older legacy cruisers and DDs can't fire the Mark-14 ERM or Mark-36 LERM; you need the bigger tubes the Sag-B and Avalon-classes were built with the carry the bigger than SDM ERM missiles.

I guess you might be able to cheat and drop to a cruiser weight warhead to free up volume for the capacitors; but even using the Mod G tech to squeeze out more efficiency from the warhead that's not a great solution. But that's the only approach I see for building an ERM that could fit in the current missile tubes.

Thank you for thevery comprehensive answer jonathan.

saber964 wrote:Whose to say that Hercules wasn't given some weapons upgrades like ERDM or the equivalent of a Mk 16 Mod G warhead upgrade for her Mk 13 capital missiles. Also for Hercules you could add better long range targeting.

actually, that brings another group of points in favor for the Hercules, all of which are operational factors.

From A Rising Thunder, we learned that a Scientist only has ~50 broadside control links, about a %50 redundancy. A RMN SD usually has a 100-200% percent as built, and many were later upgraded to have more firecontrol in the pod era. so they would have at least 100 broadside control links. While this doesn't really effect the numbers of missiles the Hercules can throw in a battle, as damage builds up, the Hercules can continue to throw large salvos, where the control arrays on a Scientist/Vega are more likely to limit salvo size as damage is taken.

You will also see other, deeper redundancies in RMN craft over SLN ships, As the RMN saw ships being lost, it learned from the experience and increased redundencies and damage resilience.

Maintenance is another consideration in this. We saw at Spindle that the maintenance levels of the SLN ships were far less than RMN standards. So the chances that critical equipment is not working, or fails under pressure during battle, is much higher on an SLN ship.

The crews are also a factor. The RMN crews are all veterans or elite units. Even new ships have crews which are so well trained and experienced, there probably no "green" units in the RMN. SLN SDs have not seen real combat in over 300 years. Even the most senior petty officer, no matter how seasoned, has not seen combat, and does not know how he will react under fire.

Another point Jonathan covered lightly is the FTL comm and Ghost Rider drones. A single RMN ship can deploy enough drones to give full sensor coverage of the region around a planet and the hyperlimit. The FTL comm allows near realtime knowledge of what is happening, and lifts the fog of war. The chances of an RMN craft maneuvering into an optimum position at the start of the battle is many times higher than an SLN ship surprising the RMN ship or out maneuvering it.