PLAN Catapult Development Thread, News, etc.

[Jura The idiot]

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However, I can see the merit of railgun or coilgun in those regions, mainly a logistical one - without the need for propellent charge, more ammo can be pulled by the same truckload, this is critical because we do know that internal combustion engines produce less horsepower at higher altitude.

LOL I'm wondering about the weight of your "more ammo", and about the number of fuel trucks needed to generate the electric power

 

[davidau]

CG of Type 003 - CV-18, flat-top, conventional but purported to be with electric catapaults capability....
..not sure if posted before?..

 

[Gustaf Adolf]

CG of Type 003 - CV-18, flat-top, conventional but purported to be with electric catapaults capability....
..not sure if posted before?..

Is there a reason why the catapults converge on the 18th while they are parallel on the 19th?

 

[Dfangsaur]

Is there a reason why the catapults converge on the 18th while they are parallel on the 19th?

because it's fan art

 

[Mirabo]

The CG also shows 4 catapults, while rumors suggest that there will only be 3 on the 003.

 

[Figaro]

because it's fan art

And a pretty inaccurate one too ... the author has already gone out of his/her way to include navalized J-20s in the second photo.

 

[by78]

Another satellite photo of the catapult research facility near Shanghai... Unsure when this was taken.

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(2048 x 600)

 

[taxiya]

There is another type of Arresting Gear system studied by Naval University of Engineering. The programme received state funding around 2013, and published one of its outcomes in 2016.

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Method of arresting cable tension control

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(National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan 430033, China)​

Abstract:
Aircraft arresting gear is a vital safety device for the airfield to ensure normal landing and block the aircrafts which are accidentally out of runway. According to the condition that the mechanical arresting gear used at the present stage cannot meet the arresting needs of future carrier aircraft types, a kind of electromagnetic arresting gear with arresting electric motor as energy absorption components was put forward. A model of electromagnetic arresting gear considering the effects of kink wave was built. The closed loop control algorithm of electromagnetic arresting gear was designed and was validated by simulation.

Things worth to note:

1. This is not the system shown on CCTV program. That system is in the same principle as AAG from General Atomics.
2. The CCTV system and AAG both use "fluid turbine" aka water twister as the main energy absorbing device. The electrical motor in such system is to complement (in a less contributing role) the fluid turbine. The electrical motor is also part of the control system to provide variable torque during the arresting.
3. The system in this article removes the "fluid turbine" using the motor as the only device. It is therefor a pure electromagnetic arresting gear in the same technology league as EM cat.
4. The AAG and CCTV system therefor is a "electro-mechanic" arresting gear. Not a real or pure electromagnetic arresting gear in the same league as EMALS or Chinese EM cat.

Quote from the research paper:

然而，由于先进阻拦装置采用的是电机及水涡轮为吸能元件的混合型方案［９］，在阻拦调节过程中仍然不够灵活，为此提出一种电磁阻拦装置方案，其系统构成如图１所示。其特点为完全采用电机作为阻拦过程的调节及吸能元件，以便充分利用电机完全精确可控的优点，实现在飞机阻拦过程中对其阻拦轨迹进行实时闭环调节。

Translation

However, because AAG combines electrical motor and water turbine (twister) as energy absorbing device, it is deemed not flexible enough during arresting. Therefor we propose an electromagnetic arresting gear illustrated in figure 1. It's character is solely using electro motor as the energy absorbing and adjustment device, to fully utilize the advantage of accurate controlling capability of electrical motor, so to realize realtime close-loop adjustment of aircraft arresting process.

Quote from GA patent

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An arresting gear for quickly decelerating a moving object includes an elongated shaft that defines a rotation axis. A tapered drum that is wound with a purchase cable is mounted on the shaft for rotation about the axis. The drum and the shaft are rotated during the pay out of cable from the drum as the moving object engages and then pulls on the cable. The arresting gear includes an energy-dissipating fluid turbine, such as a water twister, that is mounted on the shaft to apply a torque on the shaft that acts to decelerate the rotating shaft. To complement the energy-dissipating fluid turbine, an electric motor is coupled to the shaft for creating a decelerating torque on the shaft. An electric motor control system is configured to use motor rotation feedback from the electric motor to pay out the cable from the drum at a substantially constant tension.

From here, it is clear that the motor is of fine tuning the torque rather than being the main energy absorber.

 

[YYZJ]

From your own quote: "It's character is solely using electro motor as the energy absorbing and adjustment device." If this to be trusted, it would be both the fine torque tuner and energy absorber.

 

[taxiya]

From your own quote: "It's character is solely using electro motor as the energy absorbing and adjustment device." If this to be trusted, it would be both the fine torque tuner and energy absorber.

First to clarify, it is my translation of the original Chinese paragraph from the research paper that was quoted, not my own words.

Secondly, your understanding is correct.

P.S. if you expect an answer/reply from me, please reply to my post or @me so I would receive a notification in my mail box, otherwise your post would have gone unnoticed.