PRC/PLAN Laser and Rail Gun Development Thread

[SilentObserver]

So this means with DDG-1000's total power of 78MW they can't really run two such rail guns at full power simultaneously? because that will consume 50MW leaving only 28MW for the rest of the ship including radar (sounds risky to me). I can only speculate this is one reason they prefer AGS, that railguns can't both run at full power.

Yes, it means a combination of things, the current DDG-1000 can:

• Sustain rapid fire of 1 rail gun at full power, while travelling at speed.
• Slow down the rate of fire for both, while travelling at speed.
• Decrease power for both guns to maintain rate of fire.
• Slow down its ship speed to divert more energy to rail guns and rapid fire both guns at full power
• To squeeze extra energy it could lower the power diverted to electronic units like radar.

The precise combination of power levels for each unit is still a mystery but its a rough estimate based on available information. There is not enough power for all units to be at full power at once and sustain it, though it would be available for short bursts, whether it's the drive unit, rail guns, and electronics. It makes sense why the DDG1000 opted for the conventional AGS, this way it's able to operate at full capacity.

 

[latenlazy]

So this means with DDG-1000's total power of 78MW they can't really run two such rail guns at full power simultaneously? because that will consume 50MW leaving only 28MW for the rest of the ship including radar (sounds risky to me). I can only speculate this is one reason they prefer AGS, that railguns can't both run at full power.

1) That’s what storage is for. Available power is going to be more than generator output.
2) The guns wouldn’t draw that much power continuously, and in fact that draw time is relatively short, so the impact on power supply for other subsystems isn’t as extreme as the numbers may look.
3) The guns probably wouldn't normally fire simultaneously. If both were firing multiple shots at once they’d probably taper their firing sequence.

 

[Jura The idiot]

I now went through what had been posted here while I slept, will react just to Western-fanboish claims; number one:

The rail gun system allows for a more compact ammo storage.

...

Jul 10, 2017

...

(I've heard the spin of 'saving space' by shooting just small, inert metal rods off a railgun, as compared to a conventional gun which needs a magazine, is dangerous to operate etc. ... in fact huge space/amount of fuel is required to produce the electricity for a railgun: something which railgun proponents don't advertise

 

[Jura The idiot]

I now went through what had been posted here while I slept, will react just to Western-fanboish claims; number two (#1 is right above):

Yes, it means a combination of things, the current DDG-1000 can:

• Sustain ...

... did your sales talk refer to the unarmed vessel, which limped to San Diego, with "the current DDG-1000 can"? LOL!

 

[Jura The idiot]

now this:

...

Additionally, for the F-35 the price has been kept under 90 million dollars per plane, which is very reasonable considering the capability.



...

sounds like a LockMart ad, while Jan 22, 2018

6530/34 is about192
... etc. (dated JAN. 18, 2018): Belgium – F-35 Joint Strike Fighter Aircraft

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the point is the price is way higher if one looked at ALL contracts relevant for a particular lot, not just one particular production contract:

May 30, 2017

... I checked myself what I found in Internet ... well it doesn't seem to make sense but:

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says 'Lot IX' $698032385

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says 'Lot IX' $60000000

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says spares for Lot 9 $237765479

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says nonrecurring items for 'Lot IX' for $431322997

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several items for Lot 9 $430878490

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something for 'Lot IX' for $120555991

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says 'Lot IX' $ for $5370955495

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several items for Lot 9 $181765203

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says Lot 9 $743169377

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this one is particularly funny: "... to provide additional funding for affordability-based cost reduction initiatives in support of low-rate initial production Lot 9 F-35 ..." $137834819

LOL I skipped several contracts below $100m but still:
698032385+60000000+237765479+431322997+430878490+120555991+5370955495+181765203+743169377+137834819 = 8,412,280,236
(of course they said 'a $6.1 billion deal'
Lockheed ‘Disappointed’ by Pentagon’s Latest F-35 Contract November 2, 2016

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)
8412280236/57 is almost 148m ... for one of Lot 9 without an engine and so called LOT 9 AIRFRAME UPGRADE AND RETROFIT CONTRACTS
... apparently also documented in the mind-boggling link
Unit Cost of F-35s Delivered This Year Still Exceeds $206M

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it's getting off topic, so I finish with this:
I'm totally pro-West, just don't like how Sales Departments try to play me

 

[SilentObserver]

I now went through what had been posted here while I slept, will react just to Western-fanboish claims; number one:


Jul 10, 2017

I'm not a fanboy, just someone who likes to dig into the maths.

My argument was that the volume of the fuel needed to be turned into kinetic energy for the rail gun is less than the conventional propellant charge, thus rail gun space savings for the propellant. Read my calculations, correct me if there are any mistakes there. I have factored in efficiency losses and made some assumptions, came up with a system efficiency of 7.7%.

BAE 32 MJ rail gun and the AGS are comparable systems.

BAE 32 MJ uses 12L of fuel per shot (electricity converted from turbine engine)while a conventional AGS artillery has a propellant charge that takes up 32 L of volume. Making the rail gun more space efficient, this is independent of the warhead, just the propellant equivalent volume. In addition the fuel consumed would amount $12 per shot where as the conventional gun's propellants would cost hundreds of dollars per shot.

My calculations
Based on BAE 32 MJ railgun data:

• 25 MW sustains 10 rounds/min
• 25 MW = 25,000,000 J/s , Energy consumed per shot = 6s * 25,000,000 J/s = 150,000,000 J
• Rail gun efficiency: output/input = 32 MJ / 150 MJ = 21.3%
• Turbine efficiency: 40%
• Electricity transmission efficiency: 90%
• Total efficiency of chemical energy (fuel) to kinetic energy (projectile): 0.213*0.4*0.9 = 7.67% efficiency

• 32 MJ = 8.89 kWh
• 8.89/0.0767 = 115.9 kWh of fuel energy
• 1 litre of Diesel = 10 kWh, 115.9 kWh = 11.6 L/round

Advanced Gun System (AGS) on DDG 1000

• Propelling charge dimensions (estimate): r = 100 mm , h = 1000
• Propelling charge volume (estimate) = 31.5 L

11.6L/31.5L= 36.8%

Therefore a rail gun system is more space efficient than a comparable conventional artillery platform. The rail gun propellant uses 37% of the space of a conventional artillery propellant. It is also cheaper to convert fuel into kinetic energy compared to chemical propellants. Fuel would cost $12-15/round.

 

[hkbc]

Well that's simple. For the same weight, power, and space (not to mention price) one can install 3 or 4 CIWS systems facing different directions. A type 730 or 1130 can fire at faster rates and engage multiple incoming threats at around 7km away. A EMG takes several seconds between each shot. How are the two even comparable? Once this EMG fires the first shot and assuming it destroys the missile, before it reloads second shot 10 seconds or so later, the other missiles would have already hit. Why is this not obvious? A CIWS would spray into first and following missiles and delivered thousands of rounds. Yes I get the rounds are different but please be realistic. EMG for CIWS is not realistic. At least not the one we're seeing. That is what we're discussing after all since it's the only one we have seen. If you're talking about miniature guns then I'm not interested. Lowering the power would also mean lowering muzzle velocity.

Not saying that particular gun is suitable for point defence it clearly isn't but that an EM gun changes the calculus of point defence not sure why that's a puzzle! the current gun is way too big so will be slow to traverse, but just like you have guns of different sizes for different purposes a smaller one won't have the same issue, you are stuck in the paradigm that a CIWS needs to fire a 'wall of lead' of small projectiles to be effective I disagree once the technology is refined it will be much easier to scale a EM gun down than a 'chemical' gun, it should be more accurate at short ranges as it's projectiles as less affected by gravity and also has little in the way of recoil forces on the mount as for rate of fire that's a function of available power and barrels.

All you are saying is by fitting more 1130's on a hull a ship is not sunk, well since the most any Chinese vessel fits is 3 by your logic lob 4 missiles at any Chinese ship and it's toast, this naval warfare lark is really easy, not sure what all the fuss is about! I mean in the real world ships don't move as a fleet of vessels offering mutual support with a variety of capabilities deployed on different vessels, they just sail around singularly waiting to be picked off by a rainstorm of opposing missiles, rinse and repeat till they're all gone, so obvious!

I am not disagreeing that the gun on show is unsuitable for point defence but conceptually ruling out EM guns as completely unsuitable, really! Comparing a prototype with a functioning system then dismissing the prototype as useless you might as well stick with the bullock cart after all how's burning anything in a lump of metal ever going to get a cart to move!

Finally, I guess I must be in the presence of royalty, didn't realise this was your personal forum and that what you are interested is what matters!

 

[Jura The idiot]

I'm not a fanboy, just someone who likes to dig into the maths.

...

My calculations
...

will you also calculate the additional fuel needed to power a railgun?

 

[SilentObserver]

will you also calculate the additional fuel needed to power the railgun?

Power the rail gun as in its drive system and electronics? That doesn't have to be included as a conventional gun system would consume that energy from fuel as well.

 

[ougoah]

Not saying that particular gun is suitable for point defence it clearly isn't but that an EM gun changes the calculus of point defence not sure why that's a puzzle! the current gun is way too big so will be slow to traverse, but just like you have guns of different sizes for different purposes a smaller one won't have the same issue, you are stuck in the paradigm that a CIWS needs to fire a 'wall of lead' of small projectiles to be effective I disagree once the technology is refined it will be much easier to scale a EM gun down than a 'chemical' gun, it should be more accurate at short ranges as it's projectiles as less affected by gravity and also has little in the way of recoil forces on the mount as for rate of fire that's a function of available power and barrels.

All you are saying is by fitting more 1130's on a hull a ship is not sunk, well since the most any Chinese vessel fits is 3 by your logic lob 4 missiles at any Chinese ship and it's toast, this naval warfare lark is really easy, not sure what all the fuss is about! I mean in the real world ships don't move as a fleet of vessels offering mutual support with a variety of capabilities deployed on different vessels, they just sail around singularly waiting to be picked off by a rainstorm of opposing missiles, rinse and repeat till they're all gone, so obvious!

I am not disagreeing that the gun on show is unsuitable for point defence but conceptually ruling out EM guns as completely unsuitable, really! Comparing a prototype with a functioning system then dismissing the prototype as useless you might as well stick with the bullock cart after all how's burning anything in a lump of metal ever going to get a cart to move!

Finally, I guess I must be in the presence of royalty, didn't realise this was your personal forum and that what you are interested is what matters!

Chill. Simple misuderstanding. People were throwing around the idea of using this particular machine as some CIWS. I was more addressing this particular idea rather than using EMG as CIWS. Who knows how this program will develop. I think we are both in complete agreement on what THIS particular gun probably cannot do but what is possible with this technology.