PLAN Carrier Strike Group and Airwing

Re: PLAN Carrier Construction

kwaigonegin said:

I do not disagree at all but I was refering more to the layout and design of the ship as oppose to the powerplant, subsystems etc. Powerplants are powerplants... if PLAN wants to 'study blueprints of nuclear powerplants there are much better ways of getting it than from the Ukranians. Like you said Kirov has them too they don't need Ulyanovsk blueprints for that.

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That's definitely a good point, and having that extra technical know-how would at the very least better enable the PLAN to avoid the mechanical pitfalls that the French fell into with the CdG when they modified their sub reactor design for surface ship use.

Re: PLAN Carrier Construction

Engineer said:

Reducing speed, also known as slowing down, is counterproductive when the goal is to launch the aircraft in the shortest distance possible. The aircraft actually needs to increase speed to get away safely, which is what a catapult is for. A ski ramp does not add any acceleration to the aircraft, and does not reduce take off distance the way you have imagined.

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The ski ramp lets an aircraft get away at lower speed but also at a lower lift coefficient than needed for sustained horizontal flight, so at a lower induced drag. This gives it time to accelerate in the air enough to reach horizontal flying speed even in the case of failure of the critical engine at the moment the wheel chocks are retracted by the ship. That is the concept behind the use of a ski ramp with multi-engine aircraft. You will have to differentiate between the case of take off with engine failure when the aircraft drops its external stores two seconds after leaving the ramp and that without engine failure. In current ships the aircraft with engine failure at the beginning of the take off run will leave the ramp with about 60% of the speed in the case without. With cats the difference might be zero as the cat senses the acceleration at any moment and compensates.
I choose 70% of the speed at which aircraft are launched according to USN norms because that gives a nice factor of 2 in the length of the cat, but the real speed norm will have to be decided by the designers based on simulations. Perhaps the speed might be less but the size of the ski ramp in Adm K and Liaoning seems to be half of the length of a USN cat.
I learned the principles of the use of ski ramps at university in lectures about V/SOL aircraft design some forty years ago.

Re: PLAN Carrier Construction

View attachment 9072

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Some clearer pictures of that giant structure.

Re: PLAN Carrier Construction

delft said:

The ski ramp lets an aircraft get away at lower speed but also at a lower lift coefficient than needed for sustained horizontal flight, so at a lower induced drag. This gives it time to accelerate in the air enough to reach horizontal flying speed even in the case of failure of the critical engine at the moment the wheel chocks are retracted by the ship. That is the concept behind the use of a ski ramp with multi-engine aircraft. You will have to differentiate between the case of take off with engine failure when the aircraft drops its external stores two seconds after leaving the ramp and that without engine failure. In current ships the aircraft with engine failure at the beginning of the take off run will leave the ramp with about 60% of the speed in the case without. With cats the difference might be zero as the cat senses the acceleration at any moment and compensates.
I choose 70% of the speed at which aircraft are launched according to USN norms because that gives a nice factor of 2 in the length of the cat, but the real speed norm will have to be decided by the designers based on simulations. Perhaps the speed might be less but the size of the ski ramp in Adm K and Liaoning seems to be half of the length of a USN cat.
I learned the principles of the use of ski ramps at university in lectures about V/SOL aircraft design some forty years ago.

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As you have said, the aircraft leaves the ski ramp at a lower speed. This is a great disadvantage, considering the goal is to actually get an aircraft to leave at the highest speed possible. Also, you pointed out that the aircraft needs to accelerate after leaving the ramp to attain horizontal flying speed. It means the take off run isn't shortened, just that part of the run is moved overboard. A catapult on the other hand truly shortens the take off run.

Even when we suppose your concept can reduce take off length, a catapult can always reduce that length more by having the power cranked up further. Essentially, your concept will always get beaten with a straight forward solution, rendering your concept infeasible.

Re: PLAN Carrier Construction

Engineer said:

As you have said, the aircraft leaves the ski ramp at a lower speed. This is a great disadvantage, considering the goal is to actually get an aircraft to leave at the highest speed possible. Also, you pointed out that the aircraft needs to accelerate after leaving the ramp to attain horizontal flying speed. It means the take off run isn't shortened, just that part of the run is moved overboard. A catapult on the other hand truly shortens the take off run.

Even when we suppose your concept can reduce take off length, a catapult can always reduce that length more by having the power cranked up further. Essentially, your concept will always get beaten with a straight forward solution, rendering your concept infeasible.

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Delft, I see your concept as sound, but overly complex, I have even transferred some of my great affection for you, to your EMALs Ramp, I believe what you mean to convey as advantages are thus, the aircraft may fly away at full gross weight, accelerate to "flying speed" on a much shorter ramp, after being accelerated up the Ramp by the EMALs Cat or Cats, and "fly away" at an optimum Angle of Attack, at a greater altitude, and therefore offer a safer departure than the cat launch off a deck parallel to the water. This concept would free the mid and afterdeck for parking, fueling, loading, and recovering aircraft. I am finally getting some of this into my Mark ONE noggin, and I do LOVE the concept, as a pilot, I like the idea of having greater obstacle clearance,,,,, but, I'm afraid the Eng is right, it is very complex, and that means expensive. Now your confidence in Sino Engineering is also catching, and their "clean slate" status at present would be good timing if their EMALs was at a pace to move ahead? a very big if??

Re: PLAN Carrier Construction

We've had this discussion before..Just keep reading from Delft's post onward.

http://www.sinodefenceforum.com/nav...ns-news-videos-photos-38-5683.html#post159854

An USN C41 steam Catapult can launch this..an A6-E with twenty four 500(226kg) pound bombs and a full centerline tank... what more do you need?



An Nimitz class with 4 C41 catapults can launch, if need be , four fully laden aircraft every two to four minutes. I see no need for a cat with an ski ramp. EMAL or steam.

Just my opinion.

Re: PLAN Carrier Construction

bd popeye said:

We've had this discussion before.

An USN C41 steam Catapult can launch an A6-E with twenty four 500(226kg) pound bombs and a full centerline tank... what more do you need?

An Nimitz class with 4 C41 catapults can launch, if need be , four fully laden aircraft every two to four minutes. I see no need for a cat with an ski ramp. EMAL or steam.

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Add to this that a ski ramp takes up valuable deck space for spotting...and a lot of it.

If you can build and effectively operate cats, you will definitely eliminate the ski jump so you can launch those heavy birds, and gain all of that deck space.
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Re: PLAN Carrier Construction

Liaoning's Provincial Party Committee Secretary has just said publicly that "after the commissioning of the Liaoning, China's second home-constructed aircraft carrier will start construction at Dalian, with an estimated construction cycle of 6 years, together with 2 other 052D guided-missile destroyers. "

First, this MAY or MAY NOT be reliable. But I believe it should be as it corresponds to what we have known so far (North and South each will build a carrier, with the North start the construction of 052Ds). Although the number of 052Ds does differ from what we have known (2 vs 4).

Second, in the original report what he said was "国产" which literally translates into "country-made" or "country-produced" or "country-manufactured". So, by "second" he could mean that Liaoning is the first OR he could mean that the carrier at Shanghai has already started construction (which may be those structures we have seen in photos).

These are just some of the possible interpretations of his words and some of my own speculations. Do take it with a grain of salt.

For those who are not familiar with Chinese system, a provincial party committee secretary (also known as "party-chief") is the highest level party official in a province. Although the provincial governor is the head of government, the "party-chief" has actually higher rank and higher power than the governor. Also, many provincial level or municipal cities' party chiefs, especially young and capable ones from important places such as Shanghai, will eventually rise to the most powerful elite Politburo Standing Committee, or even become premier or Party General Secretary, who's also the President, and Chairman of the Central Military Committee.

News link:

Re: PLAN Carrier Construction

If the source is right, it all sounds legit. That being said, the construction cycle of 6 years, compared with cycles of other carriers around the world, either doesnt include pre-keel laying subcomponents construction or doesnt include post launch fitting out and testing. Assuming its the latter, and keel laying happens within, say, six months, the handing over to the navy probably wont happen before mid 2019. true entry into service, witch active air wing, then probably wouldnt happenbefore end of 2020.

Re: PLAN Carrier Construction

More likely it would be the former, methinks, given most people qualify shipbuilding start as keel laying and subcomponents are usually created outside of "awareness" whereas fitting out is generally included in the "construction time".

But this entire thing is still as suspect as any other carrier construction rumour.