PLAN Carrier Construction

I'd like both of the first two carriers to be EMALS too, but it is a little fanciful for me to believe and any hypothetical reasoning for both carriers to be CATOBAR can be twisted around to be STOBAR too.

However China has other shipyards that can produce large amphibious warfare ships, but only DL and JN can build carriers in the medium term, so I wouldn't hold my breath for either of them to cease carrier production for other power projection ships

delft said:

Further thoughts:
Last year the trading in the shares of one of the two largest Chinese shipbuilders, CSSC - owner of Jiangnan Shipyard among many others - IIRC, was interrupted from May to August because of the need to reach agreement with the government about investment concerning the production of naval vessels. If it now appears that both the Jiangnan Shipyard as well as the CSIC shipyard in Dalian will build a flattop. This suggest that the Dalian yard was preparing to to build one and had been investing for years to that purpose and that the government added the Jiangnan Shipyard early last year. In view of the vast investment necessary ( proven by the fact that months were needed to hammer out the agreement ) the reason cannot have been to make use of a temporary slack in orders. Also however fast these ships might be built the decision cannot have been based on political circumstances at the time.
One possible reason is that success of the tests with Liaonang showed that China didn't need a second experimental ship before committing to large scale production. An additional reason might be progress with the development of the EM cat. These would then be built into the new vessels and next also introduced into Liaonang. This is also suggested by the delay of the start of the refitting of Adm K from 2014 to 2018. She too might then be given Chinese cats.
What of the future? I don't think China will continue to have two yards churning out aircraft carriers. Perhaps this concerns say four ships altogether after which one yard switches to LHD's and/or helicopter/UCAV carriers and the other to nuclear propelled aircraft carriers, I hope with thorium molten salt reactors

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I'm often pushing the idea that China might be further along with its EMALS research than we might think, but I wonder about where all the current needed to operate those things will come from. It may end up being that gas turbines might be the bigger bottleneck that we'll have to look out for.

latenlazy said:

I'm often pushing the idea that China might be further along with its EMALS research than we might think, but I wonder about where all the current needed to operate those things will come from. It may end up being that gas turbines might be the bigger bottleneck that we'll have to look out for.

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It is misconception that using gas turbines or nuclear power would magically result in more power output. The power output is only as high as the engineers made it to be. Also, a nuclear reactor is essentially a boiler which produces steam to drive steam turbines. So, using gas turbines would be a huge detour if the ultimate goal is to build a nuclear powered carrier.

Engineer said:

It is misconception that using gas turbines or nuclear power would magically result in more power output. The power output is only as high as the engineers made it to be. Also, a nuclear reactor is essentially a boiler which produces steam to drive steam turbines. So, using gas turbines would be a huge detour if the ultimate goal is to build a nuclear powered carrier.

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Well, not magically, but I'm somewhat doubtful that a conventional steam boiler can generate enough instantaneous power for EMALS and still fit inside a carrier efficiently. I could be wrong, since I don't know much about the capabilities of contemporary steam turbines (You're welcome to educate me on this matter, I wouldn't mind learning more.

latenlazy said:

Well, not magically, but I'm somewhat doubtful that a conventional steam boiler can generate enough instantaneous power for EMALS and still fit inside a carrier efficiently. I could be wrong, since I don't know much about the capabilities of contemporary steam turbines (You're welcome to educate me on this matter, I wouldn't mind learning more.

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No power source can provide the instantaneous power you mentioned anyway. With nuclear power, you are dealing with boilers. With gas turbines, there is spool up time which you have to deal with. The energy to power catapults is always stored somewhere, then released instantaneously when needed. For steam catapults, accumulators are used for energy storage. For EMALS, flywheels play the role of capacitors for energy storage.

Engineer said:

No power source can provide the instantaneous power you mentioned anyway. With nuclear power, you are dealing with boilers. With gas turbines, there is spool up time which you have to deal with. The energy to power catapults is always stored somewhere, then released instantaneously when needed. For steam catapults, accumulators are used for energy storage. For EMALS, flywheels play the role of capacitors for energy storage.

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Ah I see. So IEPS offers no particular advantages on this matter?

latenlazy said:

Ah I see. So IEPS offers no particular advantages on this matter?

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Integrated Electric Propulsion does not provide instantaneous power you mentioned either, although it would be a necessity for a carrier equipped with EMALS.

On a traditional ship, engines are mechanically connected to shafts driving the propellers. These engines do nothing other than propel the ship. There are separated auxiliary engines that power the ship's electrical system. This creates some issues.

Suppose a ship has four engines driving four propellers. All four engines must be running, even if the ship really needs the power from just two engines. One may suggest throttling the four engines to 50%, but that is inefficient and would not reduce fuel usage to 50%. If one of the engine is busted, there is no way to reroute power like they do in Star Trek, because each engine is connected up with a propeller mechanically. If the ship wants more power, it has to wait for the kettles to boil. Also, if the electric demand is just half of the peak demand, the half the auxiliary engines will just be sitting there.

Integrated Electric Propulsion merges the two separated systems together. The mechanically connection between an engine and a propeller is replaced by a electrical network that is part of the ship-wide electrical system. This enables the use two main engines to drive four propellers, or reroute power from auxiliary engines to the propellers should one main engine be damaged. Since these auxiliary engines will most likely be diesel engines, it is possible to adjust power output in a very short time.

With regards to EMALS, it would be possible to tap into the enormous power output of the main engines for charging on a ship with IEP. It is not impossible to install EMALS on a ship with traditional propulsion system, but space must be sacrificed for a few additional auxiliary engines that won't always be in use.

chuck731 said:

QE would be the best indicator for the likely rate of progress for building Liaoning successor. Both are being built by ship builders without prior (comparable) experiences in building very large modern combat vessels.

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The QE is a poor indicator for rate of progress, the vessel went through 3 major revisions before settling on the "final" design, then after that the incoming government flip flopped over whether it should be catobar or stobar, finally it's been further delayed by politics as the government tries to constrain spending by the MOD by slowing down the builds.

With regards to building 2 carriers unless the Chinese plan to re-use the existing Liaoning hull form they'll be taking a risk putting a 2nd vessel in the water without working out the kinks in the first. So if they are going to make radical changes to the basic Liaoning design (like a much bigger vessel) expect a gap between the 1st and 2nd vessels.

With modern modular ship building they can shrink the gap but unless they are really confident they won't be completing a 2nd vessel until they well after the builder trials of the first. Anyway don't think they are in a rush

Bltizo said:

I'd like both of the first two carriers to be EMALS too, but it is a little fanciful for me to believe and any hypothetical reasoning for both carriers to be CATOBAR can be twisted around to be STOBAR too.

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STOBAR is really an inappropriate name. The take off run on Adm K and Liaoning is longer for the two front positions, much longer for the third position than the length of the USN cats. And even so the speed at which aircraft leave the ski ramp is less than of those launched by cat from a flat deck.
If aircraft should leave the ski ramp at 70% of the speed they need from a conventional cat then a cat built into the ramp and giving the same acceleration need only be half as long, 45 rather than 90 meters. The short run from the forward positions is some 130 meters in Adm K and Liaoning so such cats would free a deck length of 85 meters for spotting aircraft and much more from the third position.
To approach the quality of USN aircraft carrier operation PLAN has two ways: experience - immensely important - but also innovation. A carrier with cats in the ski ramp is truly STOBAR.

delft said:

STOBAR is really an inappropriate name. The take off run on Adm K and Liaoning is longer for the two front positions, much longer for the third position than the length of the USN cats. And even so the speed at which aircraft leave the ski ramp is less than of those launched by cat from a flat deck.
If aircraft should leave the ski ramp at 70% of the speed they need from a conventional cat then a cat built into the ramp and giving the same acceleration need only be half as long, 45 rather than 90 meters. The short run from the forward positions is some 130 meters in Adm K and Liaoning so such cats would free a deck length of 85 meters for spotting aircraft and much more from the third position.
To approach the quality of USN aircraft carrier operation PLAN has two ways: experience - immensely important - but also innovation. A carrier with cats in the ski ramp is truly STOBAR.

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Revenge of the Jeep Carriers?