PLAN Catapult Development Thread, News, etc.

[taxiya]

A EM torpedo revolver launcher by Naval engineering university. Application date March 2022.

CN114543589A

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Fully submerged in liquid/sea water when stored.
No need to flood the tube before launch.
Torpedos are stored in their own compartment outside of pressure hull.

 

[taxiya]

Ma Weiming's latest paper stated that CV-18 uses EM arrestor, no water twister involved as I have posted here #9,203
This is the official confirmation.



In 1), it says CV Fujian is equiped with advanced EM launcher and arrestor.
In 2), it says EM arrestor consists absorption and transmission (cabling), arresting motor, emergy conversion (to electricity) and control system ...... compared with "water twister arresting technology" ......

 

[by78]

Two undated satellite images of the catapult R&D facility in Shanghai. That's large pool of water at the end of the catapult track.

 

[taxiya]

I am very surprised that many posts here saying that CV-18 uses supercapacitor as energy storage system. So I searched around and find that this notion is popular by many internet posters after CV-18's cat test.

The fact is that we only have official paper by Ma Weiming stating that his EM cat chooses flywheel. There is nothing else. So the notion of supercapacitor is for the moment baseless.

Members here should avoid spreading it without any new evidence to keep the standard of this forum high. At least people should put the notion as a question in the forum instead of taking it as a fact.

 

[taxiya]

I watched the live stream, first 1.5 hour is on carrier catapult history, PLAN history with catapults is in the last hour.
There were two points that were pretty interesting:

1. Acquiring HMAS Melbourne and its BS4 steam catapult was actually quite the unexpected windfall for PLAN, the BS4 was studied in detail and had the two earlier attempts at building carrier not being cancelled they may have been equipped with BS4 clones or derived steam catapults. Shilao showed off an internal manual (he double checked to make sure the book had a RRP, otherwise he wouldn't have been able to show this manual on air) from his collection with a section on workings of BS4:
View attachment 122099
At the time it would seem neither RAN nor UK or US thought China would go onto develop carriers and so didn't bother to remove the catapults from HMAS Melbourne. If something like the sale happened today they wouldn't make that mistake.

2. While reading through the last few pages with people saying Fujian's EM cats are powered by supercapacitors I recall having seen somewhere that that's not actually the case, and that Fujian's EM cats are in fact powered by flywheels too. In fact I recall somewhere on Weibo someone had a pretty official looking table listing the pros and cons between flywheel vs supercapacitors and it wasn't clear cut that supercapacitors are better. The team did specify in the stream that Fujian uses flywheels for the EM cats.

Maybe this is the table, it is from Ma Weiming's paper from 2016. I marked them in color, Orange: forbiding factors. Green: desirable. Blue: acceptable. It is clear that supercapacitor in the 2016s are not suitable for EM cat due to its low reliability, frequent need to replace and repair, short life. Some of the factors are unlikely going to improve over time because they are inheret disadvantages of supercapacitor (chemical degradation).

 

[WhiteBeardEdward]

is anyone got a link of article or video that can debunk the myth of conventional power cant use EMALS only nuclear power can?

 

[Intrepid]

This myth doesn't exist. At least not for people who have a professional background. That's why there is no such website to link to.

 

[gelgoog]

That trite argument. An EMALS setup should be more energetically efficient than a similar steam catapult at converting energy to motion. If anything you should need less power to operate it. Not more. And yet there were plenty of conventionally powered carriers with steam catapults.

 

[Intrepid]

An oil-fired aircraft carrier with steam turbines can produce more power in the short term than the same aircraft carrier with nuclear reactors. This is a favorable feature of oil firing for EMALS.

 

[jackwells]

As the catapult is most likely to be installed on 002, I think this post fits here than anywhere else. I went through google earth today and got the following dates.

Shanghai facility:

• 2008/7/6 1st track construction began
• 2009/12/20 dead weight cart present on the 1st track
• 2011/11/21 2nd track construction began
• 2012/4/16 2nd track construction finished
• No cart is seen on 2nd track
• No spherical shaped structure and piping ever seen

Wuhan facility:

• 2010/8/14 earth work start
• 2011/7/29 track construction
• 2012/4/26 dead weight cart
• 2015/7/29 triangular feature on the track
• 2016/2/20 part of the track being covered
• No spherical shaped structure and piping ever seen

My rough comparison (rough due to the fact that dates of google earth photo are equal or later than events):
From visible construction beginning to cart on track: Wuhan < 9 months, Shanghai < 18 months, Wuhan caught up 8 months

• Track construction start: Wuhan = Shanghai + 36 months
• Dead weight cart shown: Wuhan = Shanghai + 28 months

If dead weight cart on track indicate the beginning of test, Wuhan had 4 years to the construction of Xingcheng test site. Shanghai had more than 7 years. There are no changes to the Wuhan facility since dead cart shown.

All these together make me conclude:
Wuhan facility had a way faster speed than Shanghai, also very confident and smooth in its test progress. Wuhan version is very mature, as much as one can test before a real aircraft launch.

What ever version (steam or EMALS) the Wuhan facility is, it is clear to me that it has an advantage in confidence and maturity to be installed on 002 as far as I can tell today.

What are the coordinates of the Wuhan electromagnetic catapult test site