Upcoming designs: regarding the Apollo ACM...

Dropping in late for the mass-driver discussion from Page 1:

We know for certain that the mass-driver acceleration is negligible in terms of range/closing speed, because the nifty Roland/Sag-C double broadside involves firing the missiles from each broadside in exactly opposite directions!

OTOH, going faster out of the tubes gets the missiles clear of the wedge perimeter sooner, leaving more room to maneuver without vaporising them all.

A neat trick would be to just drop loose missiles (just over a missile-wedge-perimeter apart) out of SD-Ps, could probably pack them in tighter than pods and less bulky when reloading or if things go wrong. Failing that (too many rails?), 'dumb' pods - with just enough thrust to push their missiles a wedge-perimeter apart between dropping and launch - would be a lot cheaper than the fancy mass-driver-equipped ones which were repeatedly mentioned in SVW and HaE as being rather expensive.
The problem with both those suggestions being that we now have fusion-powered missiles that need to be spun up by the pods before launch! So now we need complicated, expensive, retrieve-after-use-if-possible pods for a completely different reason than they had originally. Oh well.

FLHerne wrote:Dropping in late for the mass-driver discussion from Page 1:

We know for certain that the mass-driver acceleration is negligible in terms of range/closing speed, because the nifty Roland/Sag-C double broadside involves firing the missiles from each broadside in exactly opposite directions!

OTOH, going faster out of the tubes gets the missiles clear of the wedge perimeter sooner, leaving more room to maneuver without vaporising them all.

A neat trick would be to just drop loose missiles (just over a missile-wedge-perimeter apart) out of SD-Ps, could probably pack them in tighter than pods and less bulky when reloading or if things go wrong. Failing that (too many rails?), 'dumb' pods - with just enough thrust to push their missiles a wedge-perimeter apart between dropping and launch - would be a lot cheaper than the fancy mass-driver-equipped ones which were repeatedly mentioned in SVW and HaE as being rather expensive.
The problem with both those suggestions being that we now have fusion-powered missiles that need to be spun up by the pods before launch! So now we need complicated, expensive, retrieve-after-use-if-possible pods for a completely different reason than they had originally. Oh well.

Modern Manticoran missiles require external support to ignite the internal fusion reactor. A loose missile cannot be launched--it has to be fired from either a tube or a pod which ignites the generator.

SWM wrote:Modern Manticoran missiles require external support to ignite the internal fusion reactor. A loose missile cannot be launched--it has to be fired from either a tube or a pod which ignites the generator.

Well, I did write almost exactly that in my last paragraph...

FLHerne wrote:The problem with both those suggestions being that we now have fusion-powered missiles that need to be spun up by the pods before launch! So now we need complicated, expensive, retrieve-after-use-if-possible pods for a completely different reason than they had originally. Oh well.

FLHerne wrote:

SWM wrote:Modern Manticoran missiles require external support to ignite the internal fusion reactor. A loose missile cannot be launched--it has to be fired from either a tube or a pod which ignites the generator.

Well, I did write almost exactly that in my last paragraph...

FLHerne wrote:The problem with both those suggestions being that we now have fusion-powered missiles that need to be spun up by the pods before launch! So now we need complicated, expensive, retrieve-after-use-if-possible pods for a completely different reason than they had originally. Oh well.

I do wonder if launcher design hasn't or shouldn't have changed as a result of these developments. They need not provide much push, and the grav drivers that made modern missile pods desirable should make that a lot less demanding in size and power anyway. But they do have to charge up missile capacitors, which previously they either did not have to at all, or was a much less intense operation. If the missile dump truck cannot quite work given the need to charge the missiles, still there may be modifications for a "zap and drop" missile fire model.

In the past, the powerful mass drivers on shipboard launchers served two purposes. The first was to increase the missile's starting velocity, thereby increasing its powered range and reducing the window for the target's CMs and PDLCs to engage it. That requirement has been significantly reduced with the advent of MDMs and DDMs, and with off-bore targeting the loss of initial velocity is made up for by the ability to put in double broadsides at twice the rate that could be managed with old-school 'staggered ignition' salvos from a single set of broadside launchers.

However, the other purpose is still very much in evidence - the need to get the missiles clear of the ships wedge perimeter as quickly as possible.

Regarding the "off bore" launching capability of the Rolands, I've sort of assumed that it accomplished two things: longer missiles (the Mark 16's) in a thinner ship, and as stated, the ability to fire a missile out of the front and back of the ship while maneuvering. The "firing in two different directions bit" in this thread got me thinking though, "out the front can pretty much go straight ahead, out the back has to use the 120 degrees to turn and then go straight ahead", and the launch times are synchronized to make it all line up. Alternatively I could see the DD slewing "in position" with "no accel briefly" and launching in a position that would resemble the horns of a bull.

Then the "stacked salvo" thought kicked in and says "ny-ope..." because even with say a 15-30 timing difference, that's still a huge distance at "battle speed and accel". Because we're told that the missiles acceleration is preset and doesn't vary after it's lit off, about the only solution I've come up with is that the "stack" missiles are timed to arrive on target nearly simultaneously (or at least within a single "countermeasure time period", vs. the same number of missiles in pods being precisely the same speed/accel because all of the missiles light off simultaneously, an easier task altogether.

Am I missing something?

SharkHunter wrote:Regarding the "off bore" launching capability of the Rolands, I've sort of assumed that it accomplished two things: longer missiles (the Mark 16's) in a thinner ship, and as stated, the ability to fire a missile out of the front and back of the ship while maneuvering. The "firing in two different directions bit" in this thread got me thinking though, "out the front can pretty much go straight ahead, out the back has to use the 120 degrees to turn and then go straight ahead", and the launch times are synchronized to make it all line up. Alternatively I could see the DD slewing "in position" with "no accel briefly" and launching in a position that would resemble the horns of a bull.

Then the "stacked salvo" thought kicked in and says "ny-ope..." because even with say a 15-30 timing difference, that's still a huge distance at "battle speed and accel". Because we're told that the missiles acceleration is preset and doesn't vary after it's lit off, about the only solution I've come up with is that the "stack" missiles are timed to arrive on target nearly simultaneously (or at least within a single "countermeasure time period", vs. the same number of missiles in pods being precisely the same speed/accel because all of the missiles light off simultaneously, an easier task altogether.

Am I missing something?

Well, off-bore mostly seems to involve bring bows-on to the target (minimise target area), so the missiles don't have to travel any further.

Not sure if broadside off-bore (180 degree) is possible, but if it is, "all" that is required is to step down the acceleration of the direct missiles to enable the off-bore missiles to catch up.

SharkHunter wrote:Then the "stacked salvo" thought kicked in and says "ny-ope..." because even with say a 15-30 timing difference, that's still a huge distance at "battle speed and accel". Because we're told that the missiles acceleration is preset and doesn't vary after it's lit off, about the only solution I've come up with is that the "stack" missiles are timed to arrive on target nearly simultaneously (or at least within a single "countermeasure time period", vs. the same number of missiles in pods being precisely the same speed/accel because all of the missiles light off simultaneously, an easier task altogether.

Am I missing something?

(the problem being, if I read your post correctly, that simply having the second wave go faster for the whole trip leaves it with a higher velocity than the first wave when it catches up?)

Maths, and a convenient implication of multi-drive missiles.

The acceleration rate and the period of acceleration can both be set before launch, so you can set the first wave to accelerate more slowly for a longer period of time, and the second wave to accelerate more rapidly for a shorter period, such that the overall delta-v is the same. Because the second wave gets its acceleration in earlier than the first its average velocity is higher, so it catches up the first wave, but the final velocities are identical.

Now (as usual) there are problems with this: The second wave's drives have burned out well before they catch up with the first wave, then the first wave's burn out the moment the second stage catches up with them - so you don't even get any powered flight once the missiles have matched position and velocity...
...except that we now have this shiny new second drive! So after the two waves combine and the first wave's drives burn out, you can light off the second stage - with matched settings across all the missiles - and suddenly the enemy have a single wave of missiles coming at them under power, exactly the same* as if they'd been launched together.

*You'll lose some closing speed: DDMs have easily enough time on their drives to make the whole trip at maximum acceleration, whereas in this case the first stages are run at a lower accel in one wave and shut down early on the other. Not that it'll help the SLN, of course.

--snipping--

FLHerne wrote:

SharkHunter wrote:Then the "stacked salvo" thought kicked in and says "ny-ope..." because even with say a 15-30 timing difference, that's still a huge distance at "battle speed and accel"...

Am I missing something?

Maths, and a convenient implication of multi-drive missiles. ...

...except that we now have this shiny new second drive! So after the two waves combine and the first wave's drives burn out, you can light off the second stage - with matched settings across all the missiles - and suddenly the enemy have a single wave of missiles coming at them under power, exactly the same* as if they'd been launched together.

Brilliant!.That actually even lets me play some games with the enemy, because you could even sets the "stacked salvo" to have different length ballistic missile phases an resumption accel rates to achieve the "stacked salvo on target" saturation while really screwing around with a tac-officer's "brain" in terms of forcing too many options for "what the hell are those Manties thinking/doing?" without any additional complexity for the controlling RMN ships "per stack".

Dafmeister wrote:In the past, the powerful mass drivers on shipboard launchers served two purposes. The first was to increase the missile's starting velocity, thereby increasing its powered range and reducing the window for the target's CMs and PDLCs to engage it. That requirement has been significantly reduced with the advent of MDMs and DDMs, and with off-bore targeting the loss of initial velocity is made up for by the ability to put in double broadsides at twice the rate that could be managed with old-school 'staggered ignition' salvos from a single set of broadside launchers.

However, the other purpose is still very much in evidence - the need to get the missiles clear of the ships wedge perimeter as quickly as possible.

If the ship is maneuvering, kick them out the stern and the ship'll leave them behind at several km/s2. It works for missiles in pods; it'd work for individually-launched missiles.