That MIT paper is a very good find, thanks for posting!!!  Brought back a lot of memories from my days dealing with big floaty things as opposed to things which go bang  ;)

A gun mount that can throw 327 shells occupies the same volume as 100 not 300 rockets as you describe [See PDF discussing USS Thorn conversion on the MIT PDF in the previous including COSTING that I provide you. That design study has been done.]

Herald.

...so I'll start small:

 

page 25, Anti-Surface Warfare / Strike Warfare

last few sentences:

"It might be possible to fit the DDG-51 with one of the 155mm guns to be carried by the DDG-1000; it would likely require the removal of both the DDG-51's 5-inch gun and its forward (32-cell) VLS. In this configuration, the DDG-51 might carry about 120 of the gun's 155mm shells.

 

   The 155mm guns on the DDG-1000 could be replaced in the future with an electromagnetic railgun or directed-energy weapon. The DDG-51 does not have enough electrical power to support such weapons."

 

A lot more speculation in there than proven fact:

"might be possible", would likely require" and "might carry about" aren't proof-positive, solid-numbers answers.

Sounds like a lot of estimation thrown in moreso than actual engineering facts (guesstimates based loosely around generalized equipment specs).

Estimation, speculation, and semi-educated guesses is something you expect from someone like me,

not from someone supposedly high up in a given military branch who's trying to make a hard-sell case for a specific weapon system or program.

 

Another issue is the power.

Yeah, as it sits now, a Burke is designed around 8MW of electrical generation.

(but remind me again the actual output capacity of those LM2500s: something like 33,000shp a piece?

That's what?

, if kW = hp x 0.746-ish, that's about 24&1/2 MW apiece,

providing they're coupled to adequate generators that can handle that mechanical torque.

In a perfect world, that's 98MW, if the Burke had room for the generators!)

 

Way back in the day, post-WW2 saw the USN undergo the FRAM Fleet Rehabilitation And Modernization,

in which many hulls were upgraded and improved:

excess gun mounts were replaced by early missile systems,

anaolg gun directors were replaced with early electronics equivalents,

radars were added,

better ASW systems,

some vessels even received the first shipborne helicopters in the USN.

And certainly, as those vessels became more power intensive, the means were found to incorporate additional power generation (even if not on the scale of the difference between a current Burke and what's anticipated in a DDG-1000).

 

Seeing as a single AGS mount and a full magazine is obviously not going occupy both the volume and weight of both the Mk45 and its systems and a 32-cell Mk41 VLS,

what're the odds that an additional newer-generation power generation system could be installed there also?

Let's not assume that the intention is solely to power a 64-MJ railgun: if that gun does ever manifest onto the DDG-1000, then rest assured that there will be numerous other railguns built of lesser calibers and power requirements, just as there are multiple calibers of chemical propellant guns today.

Same goes for directed-energy weapons: every laser, particle beam, or whatever kind of electron cannon or undiscovered particle technology gun isn't going to require 60+ MW of power to operate, not as we learn to refine the power efficiencies of its components.

And by that timeframe, it's well possible that military budgets will not be able to afford $15-20B on single ships equipped with these fanciful weapons, so it should be almost logical (and cost practical) to have some kind of future FRAM in the works in that day and age (more than just SLEP-ing a hull).

And it's a safe assumption that, even if the earliest production Burkes are reefs or third-world navy vessels by then, it's safe to assume that the most recently-built hulls will still be in USN service (especially if we expect to maintain a 300-ish ship navy for a few decades somewhere in the coming future).

 

The more high-tech bells, whistles, and gee-whiz gizmos that we develop in the coming years, the more expense they'll add to the next generation of completely new designs.

So certainly we need to expect that at some point they will need to be backwards-compatible enough to still be installed into that day and age's currently-in-service vessels.

 

Why do we need to assume that we'll only ever use a railgun on the DDG-1000?

Can't future powerplant designs offer much more juice than the Burke's current 8MW?

And will they be so utterly big to the point that there's no chance in hell they could be specifically engineered in mind to be

installed into still-serviceable Burke hulls?

 

I thought the idea of the DDG-1000 was in part to test new technologies that will, obviously, spiral out into the fleet, not just stay DDG-1000/CG(X) specific...?

If the cost of a DDG-1000 gets too close to that $10B mark (something I posted ages ago, which wouldn't surprise me by the time we get to hulls 5, 6, 7, etc; look where we've ended up already with LCS, and they're not even fully fitted out and service ready yet!),

then a redesigned Burke hull incorporating as much spin-out as possible will most likely be the only cost-allowable alternative we have.

 

A lot of speculation there also: could bes, might bes, maybes, and what ifs.

But judging by the way military budgets have ballooned out then gotten trimmed left and right over the last 2 decades (even cancelled outright, regardless of how promising),  

I certainly see the merit in it: using a new Burke in place of DDG-1000s and CG(X) whose individual costs skyrocket beyond what we can afford, even if one or two of them are superior to half a dozen Burkes.

In that case, just how few ships can our USN effectively operate with?

250?

200?

Less?

We can't afford to build a few dozen $10+B ships (especially if we expect to replace some aging carriers with a few of the newer CVN-21 design).

But if we can design a new Burke for even a generous $5B (packed with spun-out DDG-1000 tech), we might actually see more than 5 or 6 (10-20years out). 

And railguns or not, rest assured there'll still be plenty of missiles.

 

 

Maybe in developing the P44 series, LockMart was doing some in-house speculation of its own, as to what to fall back on if the DDG-1000 and its AGS gets cut back/delayed, or even axed outright.

The P44, and possibly a revamped POLAR, will offer comparable (growth potential) fire support capability to a majority of USN ships, even if it means they individually can't stealthily lie on station off an adversary's coast and throw several hundred rounds at him.

According to the USS Thorn conversion doc (closer to a real engineering assessment), an AGS mount plus 320 rnds would occupy the same space as a Mk45 mount plus ammunition and a 61-cell VLS!

That is about accurate, but consider this, the AGS mount is throwing a more massive rocket boosted shell, that while no where near as large as the PGM rocket is designed to achieve the same range [and that would be larger than POLAR I'm afraid-almost 2/3 the size of STANDARD II] is 3X the MER range of the standard 5 inch naval gun delivered shell.

The only weapon drawback is that the shell still doesn't have interceptor rocket guidance. I'd like to see that HTK capability built into the shell.

Herald

We wouldn't be having all these ":negative waves" now would we?

Its a good concept. Cannon launched HTK vehicle just warms the cockles of my heart!

You think the SCRAMJET is any easier?

Herald

Ahhhh!  Now if you are talking abount a seperate "cannon launched" interceptror muniton thats easy!!!!   I thought you wanted that capability combined with the proposed LRLAP shell!!!!

Hells yeah, I like this idea.

'tis why I suggested a few threads back, about if an EM railgun does find its way eventually into a DDG1000,

as the technology matures and we learn to increase efficiencies,

we'll definitely be building EM guns in lesser calibers than 6" class (or greater, even?).

 

But even if we're only going to be playing with chemical energy guns for the foreseeable next half century,

that DTIC pdf I like posting up about EAPS, using a 50mm Bushmaster cannon to fire guided (course correcting) shells as a C-RAM (counter rocket, artillery, and mortar) systems,

in a 2" diameter munition,

certainly makes plenty of case for renewed interest in dedicated, gun fired anti-aircraft/anti-missile munitions for larger caliber guns.

All the better from a railgun, as that added velocity compared to CE guns means reduced time of flight to target, and lower ballistic loss (proper terminology? it doesn't droop as much because of gravity over the same distance) and less crosswind interference.

But even still for CE guns, the ability to fire HTK rounds at both aircraft and missiles, while still a few dozen km away,

certainly should be within our grasp.

(Shucks, we were firing off Sprint ABMs back in the day that accelerated to a phenomenal 6miles/sec, and built mostly with hardened tube tech and the earliest IC chips,

so I don't see the reason why we can't do better today, with modern microminiature electronics that, I would think, can be built to fare much more reliable than the umpteen thousand G's of an accelerating Sprint.)

 

Dual ammunition for shipborne guns isn't uncommon: a general purpose surface role (LRLAP in this instance),

and a more dedicated AA/AM munition that, much like in WW2 in the early days of proximity fuzes,

is used principally against airborne threats.

 

How far down can we shrink an NCADE sensor/guidance system, and still make it work from a gun-fired munition, perhaps in the 5" class...?

Unlike AAMs that, often, are built with the intention to maneuver at high G's to catch evading targets,

a gun-fired AA/AM guided munition shouldn't need that level of complication, as the gun is providing the majority of velocity at launch.

 

Hey, wait a minute: isn't this how the Italians' DART round for the 76mm naval gun works now?

(currently being marketed as part of the STRALES system:  link )

www.otomelara.it/EN/Common/files/OtoMelara/pdf/business/naval/development/STRALES.pdf

 

Here.

ERGM was a failure in 2005 and has since been rebooted to try to get the costs per shell way down.

Costs of rocket assisted projectiles here.

Yes that is a small boost engine in comparison to this.

ATACM

Small cost as well.

Herald

So the 2D is an "add on" kit of sorts?  Just a question...

That is about accurate, but consider this, the AGS mount is throwing a more massive rocket boosted shell, that while no where near as large as the PGM rocket is designed to achieve the same range [and that would be larger than POLAR I'm afraid-almost 2/3 the size of STANDARD II] is 3X the MER range of the standard 5 inch naval gun delivered shell.

The only weapon drawback is that the shell still doesn't have interceptor rocket guidance. I'd like to see that HTK capability built into the shell.

Herald