PRC/PLAN Laser and Rail Gun Development Thread

Inst

Captain
It sounds like the gun we're seeing now is most likely to be a railgun, if they've gotten past the durability issue. A reconnection gun might be a next-generation solution to the railgun's range problems; it needs to achieve a range of at least 1000 km to be a viable anti-ship weapon, but a railgun as an initial weapon might be worth exploring.
 

taxiya

Brigadier
Registered Member
I read a article in chinese from other site saying this is not a pure "rail gun" sense which is why its a failure but a hybrid "rail mod" enhancement on the chinese version advanced gun system.
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Here is article for those can read chinese, english speaker can google translate

海軍】中共海軍的新炮
2018/02/02 08:57瀏覽1,159迴響6推薦1引用0
幾天前,一張來自武漢的照片顯示共軍在一艘072型坦克登陸艦上安裝了一門形狀很奇怪的新炮,POP3隨即宣佈這是“電磁炮”。從艦上的幾個集裝箱和登陸艦内部的充裕空間來看,這的確是一門需要很多附屬電力設備的設計,炮管上也有額外的環形外罩,應該是綫圈,所以“電磁”兩個字並非不合理。



936號“海洋山”072II型坦克登陸艦,排水量3430噸;請注意,艦體前方的開口已經被封死。

但是這門新炮並不是美國人做的或者我以前談的“電磁炮”(“Railgun”,嚴格來説應該翻譯成“軌道炮”),這是因爲工作原理完全不一樣:Railgun的炮彈是綫圈環路的一部分(所以磁場是垂直於軸向的),必須承載很高的電流,只有如此,才能提供足夠的加速度來達到Mach 7以上的初速(計劃中的性能,美軍的原型只做到Mach 5)。但是它的缺點也很嚴重:炮身雖然不必是密封的管狀(實際上只是兩條導軌,兼職做爲電流的接頭;這也是Railgun名字的來源),卻必須承受極大的摩擦力和電流加熱,所以射速和炮身壽命都是難以剋服的工程挑戰,以致去年有報導說美國海軍已經準備放棄。

武漢新炮卻有一個傳統的炮管,多出來的綫圈是圍繞著炮管的環形,那麽電流環路只存在於炮管外,產生的磁場是沿著炮身的軸向。如此一來,炮彈要感受加速度,本身就必須自帶強磁場;這是有些奇怪的,因爲永磁磁鐵並不便宜。或許共軍的研究團隊有我目前沒有想象到的妙招,或許中方因爲是稀土大國,所以可以這樣大量消費永磁磁鐵;不論這個經費問題如何解決,這種電磁加速方法的效率是不如Railgun的。

三年前我曾寫過專文評論電磁炮(參見前文《忽悠大衆的虛擬武器》),當時我對Railgun的負面意見來自兩個考慮:第一個是前面提到的炮身磨損問題,這是工程上的挑戰,中共的工程師想出工程上的解決方案(雖然還是有代價的)並非邏輯的不可能。但是第二個毛病,也就是高速動能彈在現代海戰中沒有意義,卻是物理+軍事的問題,很難想象這個武漢新炮能如何脫困。

我在這裏再詳細解釋一下:高速動能彈如果像百年前的戰艦巨炮一樣平射,因爲海平面大氣密度高,阻力大,不管初速多高,有效射程還是不可能超過40公里(這也剛好是地球曲率所造成的海面視界),而現代海戰一旦開打,就非常不可能讓敵我水面艦隻接近到這種距離。如果曲射,那麽面對能機動的目標,精度必然一塌糊塗,必須有雷達/紅外制導,炮彈的價錢一下子提高兩個數量級,接近導彈了,可是破壞力、射程和航路靈活度卻都遠遠不如,定位十分尷尬。

至於用來近防反導,射速必須極高(~每分鐘10000發),口徑反而不重要。照片裏的炮顯然不是為這個目的設計的。事實上,即使是用環形綫圈,電磁推動的艦炮射速永遠不會高於傳統火炮,所以天生就不適用於近防反導;激光才是合適的新技術。

從照片來看,這個設計似乎有傳統的炮管,那麽最可能的,就是它基本上還是火炮,只不過加上電磁助推來增程減重。如前所述,它不適合對海和對空,那麽就應該是針對打擊固定的地面目標而設計的,可以采用相對簡單便宜得多的衛星制導來打擊點目標,或者靠完全無制導的自旋穩定來打擊面目標,只要口徑夠大,能裝載足夠的炸藥,性價比還可以接受。炮彈受發射藥和電磁綫圈雙重加速,炮管的長度和厚度都可以減半,以往要10000噸的重巡洋艦才能搭載的8寸炮,現在3400噸的船就可以搞定,曲射(假設Mach 3初速)又有100公里以上的射程,那麽我想用來在臺海戰役或者對任何美軍以外的敵對方岸上據點做為火力艦進行先期炮擊,還是可能有經濟效益的。

不過我覺得這種“電磁助推火炮”最好的應用,還是把口徑增加到400毫米,也就是二戰時代40000噸級戰列艦的火炮水準。由於電磁綫圈的減重效應,10000噸出頭的055型仍然可能裝得下。除了發射200公里射程的大型彈丸之外,還可以用來為小型導彈助推(當然,加速度必須降低,否則有些零件承受不起)。照片中的武漢新炮似乎只有200毫米左右的口徑,但是它可能是第一代的原型,將來還是有向大型化發展的可能。
The guy is a Chinese speaker, but not a Chinese in strict sense if we leave out the political dimension of what China and Chinese is.

Why I say this? Because I want to emphasize the apparent Nay-saying smell all over his article. That sentiment discredits him being objective, he is saying no not because of evidence but because of wanting no.

No need to read more, just the part "額外的環形外罩,應該是綫圈,所以“電磁”兩個字並非不合理" (coil like casing on the barrel) is enough to tell. Firstly, coil gun or rail gun are all EM guns, there are no fundamental difference. Using "coil gun vs. rail gun" to somehow play down the gun is "鸡蛋里挑骨头" (searching for bones in the egg), deny for the purpose of denial. Secondly, it is known that China has tested a hybrid EM gun that employs coil and rail, there is nothing bad of it from technology perspective which should the only consideration of debate.

P.S. his Chinese is not good either, 並非不合理 is opposite of opposite which is confirmative, he is essentially saying the opposite of what he actually wanted to say.
 

taxiya

Brigadier
Registered Member
An EM gun engineer wrote on Zhihu three years ago, as a quick summary of China's EM gun situation:
  • He categorized EM guns into:
    • #1 Rail gun. What the Americans are doing in the prototypes
    • #2 Reluctance coil gun. Home bred EM gun projects
    • #3 Conduction coil gun. Used in XM934
    • #4 Reconnection gun. This seems to be the focus of Chinese implementation in the EM proportion on carriers
  • Challenges ahead of the Chinese project (not clear if it is in #1 or #4)
    • Super capacitor is non issue. He said the ship borne EM gun uses "magnetic flux compression generator" as energy storage, not capacitors
    • The "rail" is made of carbon. Rail durability is non issue
    • The challenge here is the tip of the rail is often burned, not due to friction, but due to high temperature caused by plasmatization of the aluminum shoe
Remember this was his comment three years ago. And who knows, we can't believe everything here.
This is not to dispute what you are posting, but merely to borrow your lists of the 4 types to illustrate my thought.

My understanding is that there are only two major categories of EM gun. Rail gun is in its own, the others are all kind of coil gun. The difference is that in rail gun, the rails and the projectile make a closed loop for current, projectile itself is part of the wires. In others, the coils make up the current loop, the projectile is not part of it. Any type of coil gun is essentially like maglev train or EM cat (linear motor), the coils make up the rail track or Cat track, the projectile is the train or sled (right name?) pulling the aircraft.
 

azesus

Junior Member
Registered Member
Yes they are both EM guns but they are specific detail subset difference, straight rail is railgun, which has the advantage of being easier tech wise but also disadvantage of being less useful, coilgun also called a Gauss gun named after the prince of mathematics Gauss himself is more advanced but also more difficult to build. Just like Chinese and Japanese are both yellow skin asians but I am pretty sure you wouldn't want to be mistook as the other. The author's point is saying as a purely EM gun by itself is still not useful because the technology is not stable mature and very expansive, so rather make it a pure EM gun, and to showcase the Chinese ingenuity after observed USA's failure with a pure EM gun, it would be best to make a EM Modification enhancer hybrid on the existing system, like makeing a hybrid car first instead jump a bigger technological leap and making a failure hurting your crotch doing so like USA. I think what this author's opinion is very valid foundation, making a pure EM gun is too expansive and technology not mature and stable, but making a hybrid EM modification enhancer has the best overall cost performance enhancing firepower on a weight basis making a small destroyer ship has the punching power of a battleship turret. Maglev and EMcat is like railgun, you got it wrong opposite, you can just over simplify analogy, railgun is smoothbore, and coilgun is rifled
 
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Inst

Captain
Hybrid systems for coilguns have been proposed, i.e, a chemical propellant gets the projectile up to normal speeds, then the coilgun kicks in and adds additional acceleration. But the design clearly shows that it's likely to be a railgun instead of a coilgun system, since the terminal barrel is rectangular. Moreover, the limitation on railguns is a matter of durability at high energies, so it's difficult to see how a hybrid railgun would have advantages over a pure railgun.
 

manqiangrexue

Brigadier
It sounds like the gun we're seeing now is most likely to be a railgun, if they've gotten past the durability issue. A reconnection gun might be a next-generation solution to the railgun's range problems; it needs to achieve a range of at least 1000 km to be a viable anti-ship weapon, but a railgun as an initial weapon might be worth exploring.
I dunno about that range necessity. Ship-to-ship hostilities don't always start at 1,000km out. Sometimes, they get much closer to intimidate, warn, pester, bully each other before things turn ugly and the shooting starts, in which case, the ships would be easily within view of each other at the onset of fighting.

But in any case, I don't think there is any point in further stressing that the rail gun is not a technology that supplants the missile. It's just a big upgrade over the conventional gun and we should be happy for that.
 

Inst

Captain
What's the information on magnetic flux compression generator? That makes the claim seem dodgy, since magnetic flux compression generators are, and I emphasize, explosive and single-use.
 

taxiya

Brigadier
Registered Member
It sounds like the gun we're seeing now is most likely to be a railgun, if they've gotten past the durability issue. A reconnection gun might be a next-generation solution to the railgun's range problems; it needs to achieve a range of at least 1000 km to be a viable anti-ship weapon, but a railgun as an initial weapon might be worth exploring.
I am not sure about it being a pure railgun at this moment. It can still be a coil gun or hybrid of both. The partial rectangular shape of the barrel is not nessesarily the definition of it being railgun.

As Kurutoga's post 278 and 279 demonstrated, only the pure coil gun has a circular barrel all the way, the other type like the one in post 278 has rectangular barrel. Like I said in post 283, all of them are essentially coil gun, not rail gun.

I am afraid that unless some technician in the project eventually was allowed to tell something in a future CCTV interview or similar circumstance, we will never know what type this gun is.
 

kurutoga

Junior Member
Registered Member
What's the information on magnetic flux compression generator? That makes the claim seem dodgy, since magnetic flux compression generators are, and I emphasize, explosive and single-use.

It seems there are other kinds that
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. His words were "MFCG and CFA, widely used in military projects". It seems he thought this is very common in EM gun design.
 
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I get some 20 meters of turret with barrel length. ...
... which would be about the size of
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!

(was now looking into Campbell's Naval Weapons of WW2 to check)
I of course refer just to the longitudinal dimension, don't know how wide the gun house is ... anyone?

so far I liked most the pair of doors though:
b0f88423175e7340a3dad906e8532c74.jpg
 
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