CV-18 Fujian/003 CATOBAR carrier thread

[by78]

The steam delivery system that pipes steam from onshore boilers into the carrier appears to be missing in the image. This could be a sign that verification of the ship's turbines has been completed. If so, boiler tests may begin soon.

Another flyby update. The steam delivery systems is still there, contrary to what I had believed in the post above.

Upon further examination, it appears that one of the two steam delivery systems has been dismantled, specifically the

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. Assuming it hadn't been dismantled temporarily for the long Chinese New Year break, this could mean verification of her forward set of turbines has been completed.

An image taken sometime in early November 2022, the two steam delivery systems are marked with green arrows:

Another image, taken in October of 2022, again showing the two steam delivery systems marked by green arrows:

An image taken about a week ago. The forward steam delivery system doesn't appear to be present:

 

[4Runner]

Generators with fossil boilers can be up to 47% efficient, but even old ones are 35%+ efficient.

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Linear motors are 85% efficient.

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Steam catapult is claimed to be 5% efficient.

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I think the best supercritical technologies in real-world operations are from Shanghai Electric.

 

[4Runner]

China's New Aircraft Carrier is a Game Changer​

LOL. Where have you been since this forum tilted toward anti-US people-power social media?

 

[zgx09t]

A question for those knowledgeable people here.

What kind of module/super module/super block takes at least six months to a semi-finished state?

Aug 08, 2022. In the shed.

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Oct 10, 2022. Outside now.

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Feb 05, 2023. Still there, all by themselves.

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Blocks seem to have length wise brace bars installed on top. Second block closer to the lens seems to have white enclosure forming like a shape of deep bowel. Big flat pieces lying next to it.

Kind of resembles QE super blocks.

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What that could be, a commercial construction? Then what kind of commercial construction would that be?
Even with Covid stoppage factored in, a normal commercial construction would take that long for any kind of ship?

 

[lcloo]

A question for those knowledgeable people here.

What kind of module/super module/super block takes at least six months to a semi-finished state?

Aug 08, 2022. In the shed.

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Oct 10, 2022. Outside now.

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Feb 05, 2023. Still there, all by themselves.

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Blocks seem to have length wise brace bars installed on top. Second block closer to the lens seems to have white enclosure forming like a shape of deep bowel. Big flat pieces lying next to it.

Kind of resembles QE super blocks.

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What that could be, a commercial construction? Then what kind of commercial construction would that be?
Even with Covid stoppage factored in, a normal commercial construction would take that long for any kind of ship?

Personally I hope this is an aircraft carrier, but most likely those modules are for car carrier.

Many car carriers had been constructed at this yard site, and there are still many orders for this ship type to be fullfilled.. China's car exports exceeded 2.5 million vehicles in 2022, and there is shortage of car carrier ships.

Or, it could be a large container ship.

 

[taxiya]

Thanks for the reply. When you say that the EM catapults use less energy than steam are you saying that it is more efficient to generate electrical energy than to use steam to pump the cat? If so what is your source? Do we even know how many Megawatts an EM cat complex would consume?

I will only answer the bold part as other member has answered the rest.

122 MJ is the typical value of launch energy released in 2-3 seconds. The figure is probably the max that is the heaviest loaded aircraft. The figure is from paper "Electromagnetic Aircraft Launch System - EMALS" by US Naval Air Warfare Center. It is also quoted by Ma Weiming of PLAN.

This is the mechanical energy delivered by the shuttle. You will need to take into consideration of efficiencies of linear motor, flywheel, turbine-generator to get the thermal energy of the steam. This energy consumption in a EM cat is lower than in a Steam cat. This has been calculated in the other thread dedicated to EM launcher.

BTW, it is wrong to ask how many watts EM cat consumes. Watt is unit of power, not energy.

 

[by78]

Two images taken fairly recently (less than two weeks old). The first one is a high-resolution version of a previously shared image. Pardon the dimensions of the second image, but the file size is very small (less than half a megabyte).

I know this is rather old (from around last August), but here's the rare video from which the images were taken.

 

[Hub]

I will only answer the bold part as other member has answered the rest.

122 MJ is the typical value of launch energy released in 2-3 seconds. The figure is probably the max that is the heaviest loaded aircraft. The figure is from paper "Electromagnetic Aircraft Launch System - EMALS" by US Naval Air Warfare Center. It is also quoted by Ma Weiming of PLAN.

This is the mechanical energy delivered by the shuttle. You will need to take into consideration of efficiencies of linear motor, flywheel, turbine-generator to get the thermal energy of the steam. This energy consumption in a EM cat is lower than in a Steam cat. This has been calculated in the other thread dedicated to EM launcher.

BTW, it is wrong to ask how many watts EM cat consumes. Watt is unit of power, not energy.

Sure, 122MJ is about 33.9kWh. For reference, in 2021, the average cost of 1 kWh electricity in US is about USD 0.14, 33.9kWh is about USD 4.75. Yes, EMALS is far more energy efficient than steam cat.

 

[SinoaTerrenum]

I will only answer the bold part as other member has answered the rest.

122 MJ is the typical value of launch energy released in 2-3 seconds. The figure is probably the max that is the heaviest loaded aircraft. The figure is from paper "Electromagnetic Aircraft Launch System - EMALS" by US Naval Air Warfare Center. It is also quoted by Ma Weiming of PLAN.

This is the mechanical energy delivered by the shuttle. You will need to take into consideration of efficiencies of linear motor, flywheel, turbine-generator to get the thermal energy of the steam. This energy consumption in a EM cat is lower than in a Steam cat. This has been calculated in the other thread dedicated to EM launcher.

BTW, it is wrong to ask how many watts EM cat consumes. Watt is unit of power, not energy.

Pardon my basic question but why does the launch require so much energy? Basic physics dictate Force = mass x acceleration.

Maximum loaded weight of J-15 is 32,500 kg, let's round up to 40,000 kgs for argument's sake, so mass = 40,000.
Take-off velocity on US carriers is ~170 knots/hr, or 87.22 m/s. Let's round that up to 100 m/s to be conservative.
It takes ~2 seconds to catapult aircraft off, so acceleration needs to be 50 m/s.
Taking integral of 50 m/s accelerating over 2 seconds from initial velocity of 0 is (1/2 * 50) * 2^2 = 100 meters, which is roughly the runway distance on a carrier (300 ft/90 meters but close enough)

50 * 40,000 = 2 million newtons, 2 million joules, or 2 MJ.
Even assuming a 10% conversion/efficiency ratio, only 20 MJ energy needed. Even reducing time to 1.5 seconds and acceleration to 67 m/s2 gets you 2,666,667 newtons/joules, or 2.67 MJ. Unless team catapults only 2-3% efficient?

 

[JebKerman]

Energy needed does not depend on acceleration? E = 1/2 m V^2 --> 0.5*32500*70 (250km/h) ^2 gets you 80MJ, 290km/h gets you 110MJ so 122MJ seems pretty reasonable?