054B/next generation FFG thread


Gloire_bb

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That's because the Type 31 is actually designed as a General Purpose Frigate.

Royal Navy's ASW-specialized Frigate is the upcoming Type 26 Frigate. We should compare 054B to the Type 26 actually.
Type 26 isn't exactly a specialized ASW - it's more of a heavy frigate.
24 strike cells (VL-ASROC/Tomahawk/future hypersonic missile); 5" gun; size and cost to match (well over 052D).

I doubt PLAN is looking for anything like that - just doesn't make sense. 2nd tier navies just compose their fleets differently nowadays.

That's because the Type 31 is actually designed as a General Purpose Frigate.
General purpose in this case may be misleading - because type 31s de facto are "east of Suez" colonial cruisers, with very thinly veiled focus on the Gulf area.

I.e. there is "general purpose" when a universal ship can do everything short of high-end fleet on fleet work. That is one type of general purpose.
Then there is "general purpose" - a barebones combat ship that can do something just about any true warship can - but for cheap.
This is our 31 - as it is really, really weak in actual combat.
 
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tphuang

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Use more powerful diesel engines. Diesel engines scale up to powering the largest bulk freighters and containerships in the world. The Type 071, the Type 901, and the Type 075 are all diesel engined.

For surface warship use, for example, the Iver Huitfeldt class frigate. Four 8.2MW diesel engines, each an MTU 20V. Fully loaded, its a 6,600 ton ship that can run 30 knots. It has 32 Mk. 41 VLS, plus 24 Mk. 56 VLS, which is a stand up VLS meant to individually fire an ESSM each. There are provisions for 8 Harpoons but enough space to push it to 16. This ship is being used as the basis for the RN's new Type 31 Arrowhead 140 frigate.

The Type 31 also reminds me that as much as we talk about the 054A and 054B for ASW duties, the frigates themselves are conceived mainly for general purpose.
The large ships you mentioned only need to go at low 20s in top speed. 30 knots really isn't fast enough for 054B and I'm not convinced 33 MW is enough to sustain a 6000+t ship at 30 knots. Also, 40 UVLS probably takes up more space than 32 MK-41s and 24 MK-56s. Whatever propulsion they use need to be able to handle an expansion to 6000t and probably probably sustain over 30 knots for long period of time. Does these other frigates have the requirement of keeping up with a future nuclear powered aircraft carrier?
 

AndrewS

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The large ships you mentioned only need to go at low 20s in top speed. 30 knots really isn't fast enough for 054B and I'm not convinced 33 MW is enough to sustain a 6000+t ship at 30 knots. Also, 40 UVLS probably takes up more space than 32 MK-41s and 24 MK-56s. Whatever propulsion they use need to be able to handle an expansion to 6000t and probably probably sustain over 30 knots for long period of time. Does these other frigates have the requirement of keeping up with a future nuclear powered aircraft carrier?

The rule of thumb is [Power = velocity^3]

So if you had a 50% increase in the propulsion power of a Type-054A Frigate Hull to 30MW, you would get a top speed increase from 27 to 31 knots. If you doubled the propulsion power to 40MW, that would get you to 34 knots.

It goes back to what is the purpose of a Type-054B Frigate. Even keeping up with the Type-002 carrier means 31+ knots.
 
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Tam

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The large ships you mentioned only need to go at low 20s in top speed. 30 knots really isn't fast enough for 054B and I'm not convinced 33 MW is enough to sustain a 6000+t ship at 30 knots. Also, 40 UVLS probably takes up more space than 32 MK-41s and 24 MK-56s. Whatever propulsion they use need to be able to handle an expansion to 6000t and probably probably sustain over 30 knots for long period of time. Does these other frigates have the requirement of keeping up with a future nuclear powered aircraft carrier?

Is your last question a serious one? We're talking of NATO frigates, you only need to know their exercise histories to answer this.

40 U-VLS is still speculation, and even that speculation is based off the shorter version. The 7 meter VLS only refers to 7 meters missile length so the physical size could be 8 meters and over to allow for the cold launched mechanism. Mk .41 uses a 5.8 meter canister for the Standard only VLS, but a 6.8 meter canister for the Strike version that can use the Tomahawk and SM-6. This is canister length only, you still need to add the hot launch exhaust transfer system underneath so that adds a meter plus beneath. So not much difference in terms of depth when you account for the launch systems. U-VLS might have more diameter but it does not have a separate center plenum like the Mk.41 so in terms of surface area usage, the two might also be closer than you think. The 24 Mk.56 takes up their own space as well as 16 potential Harpoons.
 

tphuang

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Is your last question a serious one? We're talking of NATO frigates, you only need to know their exercise histories to answer this.

40 U-VLS is still speculation, and even that speculation is based off the shorter version. The 7 meter VLS only refers to 7 meters missile length so the physical size could be 8 meters and over to allow for the cold launched mechanism. Mk .41 uses a 5.8 meter canister for the Standard only VLS, but a 6.8 meter canister for the Strike version that can use the Tomahawk and SM-6. This is canister length only, you still need to add the hot launch exhaust transfer system underneath so that adds a meter plus beneath. So not much difference in terms of depth when you account for the launch systems. U-VLS might have more diameter but it does not have a separate center plenum like the Mk.41 so in terms of surface area usage, the two might also be closer than you think. The 24 Mk.56 takes up their own space as well as 16 potential Harpoons.
That is a serious question. Do they have the requirements of sustaining 30+ knots for long period of time. It's one thing to join NATO formations and go 30 knots occasionally. Plan has much higher requirements than that. It will need to be able to sprint at over 30 knots for extended period of time. If you look at 055, it clearly has the power to sustain over 30 knots.

From what I know, 054a can sustain top speed of 25 knots, even though it's top speed is 27 knots. Let's say you raise that to 33 knots top speed and 31 knots sustained. And then, 054b having 10% additional wet area than 054a seems like a reasonable assumption.

(33/27)^3 x 1.1 is about 2. I wasn't just making things up when I said double the power is needed.
 

Tam

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That is a serious question. Do they have the requirements of sustaining 30+ knots for long period of time. It's one thing to join NATO formations and go 30 knots occasionally. Plan has much higher requirements than that. It will need to be able to sprint at over 30 knots for extended period of time. If you look at 055, it clearly has the power to sustain over 30 knots.

From what I know, 054a can sustain top speed of 25 knots, even though it's top speed is 27 knots. Let's say you raise that to 33 knots top speed and 31 knots sustained. And then, 054b having 10% additional wet area than 054a seems like a reasonable assumption.

(33/27)^3 x 1.1 is about 2. I wasn't just making things up when I said double the power is needed.

First of all how absolutely sure are you the 054A is truly limited to 27 knots? We see it regularly with Liaoning battle groups. Don't assume everything you read on paper is absolutely true to the right number. Top speeds you read about is just some kind of general assumed ceiling but it may not be the actual operating ceiling. Only the PLAN knows their true ceiling.
 

tphuang

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First of all how absolutely sure are you the 054A is truly limited to 27 knots? We see it regularly with Liaoning battle groups. Don't assume everything you read on paper is absolutely true to the right number. Top speeds you read about is just some kind of general assumed ceiling but it may not be the actual operating ceiling. Only the PLAN knows their true ceiling.
I don't have access to that kind of data. I am basing this also on what I hear from shilao podcast. They have talked several times about inadequacy of 054a for carrier groups.
 

charles18

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First of all how absolutely sure are you the 054A is truly limited to 27 knots? We see it regularly with Liaoning battle groups. Don't assume everything you read on paper is absolutely true to the right number. Top speeds you read about is just some kind of general assumed ceiling but it may not be the actual operating ceiling. Only the PLAN knows their true ceiling.
Isn't there a general rule that if you want to sustain 30 knots you pretty much have to have a war ship that runs on turbines, and not piston engines?
I'm not an engineer, I'm just making a casual observation here.

Only the PLAN knows their true ceiling.
All ships have to obey the same laws of physics. We know the size and shape of the Type 054A so the hydro-dynamic forces acting on the ship can be calculated. The Type 054A runs on piston engines. We know what the PWR power to weight ratio is for such engines.
Therefore the design speed of the Type 054A can be calculated. I do Not think it is 30 knots.
 

AndrewS

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I don't have access to that kind of data. I am basing this also on what I hear from shilao podcast. They have talked several times about inadequacy of 054a for carrier groups.

I would agree with that that the Type-054A would limit the overall sustained speed of the carrier group.

And if you look at the OH Perry, it's a pretty comparable conventional Frigate design to the Type-054A.
31MW of propulsion gets you to 30 knots

And the OH Perry class were noted for being too slow to fully keep up with a carrier.
 

BoraTas

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Isn't there a general rule that if you want to sustain 30 knots you pretty much have to have a war ship that runs on turbines, and not piston engines?
I'm not an engineer, I'm just making a casual observation here.


All ships have to obey the same laws of physics. We know the size and shape of the Type 054A so the hydro-dynamic forces acting on the ship can be calculated. The Type 054A runs on piston engines. We know what the PWR power to weight ratio is for such engines.
Therefore the design speed of the Type 054A can be calculated. I do Not think it is 30 knots.
No. There is no such rule. Gas turbines are used in warships and yatches because they are weight and volume efficient. Take a 6000 tons frigate and install it 2 x 30000 hp diesels and it would hit 40 knots.
 

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