CV-XX (003 carrier) Thread I ... News & Discussions


Intrepid

Captain
I suppose it's a combination of a variety of reasons. And I assume that the Chinese have very extensive access to "otherwise acquired" knowledge on this matter.
 

Bltizo

Lieutenant General
Staff member
Super Moderator
Registered Member
The Chinese have the advantage of not being the first to develop EMALS and of finding out about the mistakes and problems of the Americans at an early stage. So they could do it differently and better right from the start.

You say that, but going by their development times, they emerged around the same time (within a few years of each other which is pretty damn close for this kind of system).

Doubt there was much second mover advantage here.
 

silentlurker

Junior Member
Registered Member
If my memory is correct, the Chinese and US system are significantly different. The US system works on AC, whereas the Chinese one work on DC. I read somewhere that the Chinese mid-voltage DC system has significant technical advantages, and the US would have chosen the DC path too but at the time of Ford's design the DC technology was not yet mature.

Now depending on the nature of the Ford's EMAL problems, it may or may not be applicable to Chinese system.
Do you have a source for this? I find it hard to believe such a power-intensive system would be taking an effeciency loss from DC conversion unless there were major benefits.
 

taxiya

Colonel
Registered Member
Do you have a source for this? I find it hard to believe such a power-intensive system would be taking an effeciency loss from DC conversion unless there were major benefits.
If I understand correctly, you are questioning the reason of DC grid because you believe that there is a efficiency loss for AC-DC conversion, am I right?

If my understanding is right, the short answer is DC grid can be more efficient than AC grid on a military ship.

First of all, all generators generate electricity in form of AC. However current high power semiconductor device integrated in the generator casing can convert to DC right out of the generator with very low loss. In AC grid there is induction loss because the power wire and the surrounding metal ship structure make up like induction loop in the same way as an AC motor. So AC current will be generated within the ship taking away part of energy, that is a loss. This happens in a land power grid too. This does not happen in a DC grid.

There are also many other advantages of DC grid, some of them can save energy but the list is too long to put here.

The impact of different grid (DC and AC) is not really the core issue of Ford or 003 because neither of them are IEPS. It would be a core issue in IEPS because >70% of electricity goes to the propeller. Ford and 003 only have EM catapult which isn't big enough to cause serious problem. But I can imagine DC grid being advantageous even in EM catapult application. It is my speculation because we don't have details of the Chinese EM cat, not even a clear picture.

The problem of Ford class' EMALS and AAG is a separate question about reliability. The article did not say anything. We know the existence of reliability problem has been there from day one. Without new input by the article, it could be just the same issues.
 
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Intrepid

Captain
The USA is active worldwide and the respective armed forces on site need the aircraft carriers for their protection. The problem is that CVN 65 has long been decommissioned and CVN 78 is far from ready for action.

China does not want to get involved worldwide until sometime in the future and can afford years of tests with an aircraft carrier specially built for this purpose. The Chinese Navy is nowhere near as pressured as the US Navy.
 

taxiya

Colonel
Registered Member
The Chinese have the advantage of not being the first to develop EMALS and of finding out about the mistakes and problems of the Americans at an early stage. So they could do it differently and better right from the start.
The issues with EMALS did not show up before China started its own EM catapult program, even the US did not anticipate the troubles they are going to face back then.
 

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