CV-18 Fujian/003 CATOBAR carrier thread

[by78]

Self-explanatory.

 

[Tam]

Brown one likely tacan,green one date link ?

Tacan in previous ships like Liaoning, Shandong and 055 takes the form of a disk, similar to the USN tacan. Unless there is a tacan of a new design but I got doubts since both 055 and 075 are still using this disk shaped tacan. Its likely the tacan for the Fujian has not been fitted but I'm open to the prospect there might be a new design for the tacan.

Don't think green is data link when you already have cec in blue. Both panels are also in the 055. The ESM used by the PLAN usually has three different parts. First is a mast, like a kebob stick with arrays sticking on it. The second is for signal threat analysis. The third is for direction finding of the threat signal. Call it passive radar. ESM is extremely important for any ship's defense and they have to be placed as high in the ship for maximum radio horizon. They can also track the emissions of any aircraft both friendly and non aligned within a large airspace.

As the ship lacks the previous bar shaped IFF, this means the IFF has a new design. The new design here on the Fujian reminds me of the ring shaped segmented IFF used on the Burkes and the Italian FREMM.

Based on the mockup, black will be a series of rectangles that form a circle around the neck of the mast. Not sure what this is.

 

[Juan B.]

Well, yes, you've hit the nail on the head.

I believe that as part of the PLAN's future requirements as part of the PLA's overall strategic procurement, USN style nuclear supercarriers are necessary. I don't want to turn this thread into a discussion about what the PLA and PLAN's future requirements and warfighting doctrine and plans may be. There are multiple threads about that already, and I have described my vision for it a number of times over the years, most recently here in this post:

PLA strike strategies in westpac HIC

They will have to do a lot of construction there (like they've done in SCS) to reclaim enough land there to have such a port. They will need to help bring soil to Kiribati anyhow to help them with rising water level. Maybe they will find that is too challenging and they are only able to have a...

www.sinodefenceforum.com

If you or anyone else want to discuss it further, feel free to continue there.

But for this thread, to have context for my position -- I believe that for the PLA's future warfighting needs, I believe they will desire future carriers to be both nuclear powered, large and have aviation generating capabilities that are not inferior to that of USN supercarriers.

My position on 003's flight deck configuration and further (what I believe to be inevitable) room for improvement on future carriers, should be understood on that basis

I am exceptical about building more carriers. On one hand hipersonic antiship weapons are a very good deterrent of a modern CSG. But in the other the new series of CVNs are consuming a LOT of US Navy resources, too much in my oppinion.

Type 003 can give PLAN a CVW even a bit modern that one US Navy based on F35C can offer (at least when JC31 are operationally deployed), but... really PLANs wants to follow the trend of US Navy?, ...and at which cost?. Type 003 would also be an awesome SCS for powerful ASW fleets, but LHDs are IMO enough for that.

 

[taxiya]

Do we know how Americans solved their EMALS power distribution problem? Have they perhaps dispensed with part of the redundancy?

No idea. What is the "distribution problem"? I don't really see their solution in the diagram as a problem though. So long as you don't launch aircraft simultaneously, you are safe. It is only few seconds between two launches.

However, in any one launch, the sync between all flywheels involved and the linear motor must be guaranteed. That is the core design work of their system. Are you saying they have problem in this scenario (in a single isolated launch)? If so, that would be serious, and giving up redundancy won't help.

 

[Intrepid]

... Are you saying they have problem in this scenario (in a single isolated launch)? ...

The US Navy had serious problems to complete launch phases. They had to shut down the whole system to deal with the problems.

 

[Gloire_bb]

But not as stealthy and the payload is much more varied in the F-35. J-20 can only do CAP loadouts.

Can you reliably quantify "not as stealthy"?
I mean, not through religious "A gotta be better than B because Oceania is Oceania".

 

[taxiya]

The Royal Navy learned its lessons, such as they were, from the Type 45 destroyer and applied them to the Queen Elizabeth class carriers which have an updated 11kV MVAC grid and much better balanced prime movers.

For the benefit of other readers on the forum, it should be pointed out that that the problems suffered by the Type 45 destroyers wasn't necessarily with its 4kV MVAC grid per se, but with the decision to design the ship's peacetime CONOPS around a single generator operation mode, whereby one of the two WR-21 complex cycle gas turbine generator would provide power to all onboard systems, including propulsion. The auxiliary diesel generators weren't intended to be used in regular operation, except in harbour transits and blackout recovery. This was driven by the desire to reduce through life costs at the risk of providing no redundancy in case of a propulsion casualty. In war time, both gas turbines would be operated, reducing fuel economy but providing the critical redundancy.

The adopted IFEP system on the Type 45 was a departure from the original UK electric warship design, which was to use a hybrid AC-DC grid, where additional redundancy was built into the DC grid with its own prime movers and energy stores:
View attachment 91146

As a remedy, it seems that they are taking out the two 2MW diesel generators and replacing them with 3x 3 MW diesel generators. The ships will now run exclusively on diesel generators at low speed patrols and switch in the gas turbine when cruising.

As for the Zumwalt's, they have adopted the hybrid AC-DC grid whereby all service loads (including radars and future pulse weapons?) are delivered through a zonal DC grid. However, they have the shortcoming of operating their AC grid at the same 4kV voltage as the Type 45 destroyer whilst packing twice as much installed power. From what I've read, this makes it quite difficult if not impossible to parallel all 4 prime movers across their switchboards.

I believe that you took the figure from this document "Refining the Power Station Design of the All-Electric Warship" by Rolls-Royce Defence – Naval, in page 3.

As you can see, there are two Link Converters. On the left is DC grid that serves radar, computer, control systems etc. On their right is the propulsion which account more than 70% load (rough figure). This part is a AC grid. As I have said, only this part determines the overall architecture.

This is the same architecture as Zumwalt which is also a hybrid. They are all MVAC grid determined by the propulsion grid. This kind of hybrid does not solve the fundamental challenge/difficulties/complexities of MVAC. I suspect that US and UK share a common design root.

The remedy is addressing another issue that is unrelated to MVAC. It is to mend the gap of optimal power range (to 10MW). This is shown in Figure 2 in the same page.


Regardless how you connect the 3 3MW diesel engines, you don't change the fact that GTs are on AC grid, nor the fact that >70% of the maximum power is on AC grid.

It is a patch work that does not change the architecture. The defining point of MVDC is that the main power bus is pure DC, not hybrid.

 

[taxiya]

I don't know wether it is that easy to simply connect or disconnect busbars. I know from the electric railway that de-energizing a section is a complex operation. It is not enough to switch switches or open contactors. The sections must then be grounded. At least at 15,000 V AC this is the case. I don't know if DC is any different.

Switching off (disconnecting) any high power appliance from a grid is a very challenging work. DC is just more challenging than AC because DC does not have the zero point moment as in AC.

 

[taxiya]

But presumably you wouldn't need to disconnect the busbars in the case of an exhausted or faulty energy storage unit.

The issue, as encountered by the US EMALS, is the inability to isolate the individual catapults if any of them fails.

I think you misunderstand "disconnect". There is always a switch that connect/disconnect the storage unit and the launch motor whenever they are not used for launch even when they are not faulty.

In your home, all sockets are connected to the bus. A lamp is connected to the bus by a switch, the lamp is connected/disconnected by that switch. When the lamp is burnt, you turn off the switch before you replace it, same as repairing a faulty energy storage unit.

I don't know anything about US EMALS's inability to isolate faulty catapult. It sounds like they don't have a switch to cut it off from the bus which is unimaginable by me.

 

[Helius]

I think you misunderstand "disconnect". There is always a switch that connect/disconnect the storage unit and the launch motor whenever they are not used for launch even when they are not faulty.

In your home, all sockets are connected to the bus. A lamp is connected to the bus by a switch, the lamp is connected/disconnected by that switch. When the lamp is burnt, you turn off the switch before you replace it, same as repairing a faulty energy storage unit.

Except in that analogy the lamp is the catapult/motor and the energy store is the AC mains connected to the busbar inside your breaker panel.

So please correct me if wrong - if we were to apply the faulty lamp analogy to the US EMALS, it'd be like there's no on/off switch on the lamp, so you can't replace the light bulb without shocking yourself.