現實中的炮彈轉正效應,口徑壓制與APC

先一些翻譯,確認下文所講的詞

轉正效應->normalization <--有人提出這詞是wg原創的,目前不確定
壓制->overmatch
裝甲厚度/口徑->T/D->thickness of armour/diameter of shell (口徑似乎不太對,應該說彈體直徑)

引用來源
http://ftr-wot.blogspot.tw/2013/04/digging-deeper-1-shell-normalization.html
https://www.reddit.com/r/CredibleDefense/comments/4yd0w9/how_does_shell_normalisation_work_in_real_life/



開門見山,遊戲wot敘述的轉正效應跟現實是相反的




這張圖應是引用自"WWII Ballistics: Armor and Gunnery"

測試結果T/D對應不同角度的數據
範例
T-34 45mm 60度裝甲,等效是90mm 0度
對上88mm apc/apcbc T/D大約是0.5,根據上表對上60度裝甲,slope multiplier大約是2.5
也就是T-34裝甲對上88mm apc/apcbc等效約113mm

一般wot中所講的轉正應該是指口徑壓制,或其實應該稱壓制(三倍口徑壓制又是另一個遊戲機制)

另外提到APC,APCBC
APC彈頭前面有一層cap不是為了增加轉正效應,而是減少高速彈頭撞擊裝甲時破碎的可能

而現代的穿甲桿用很細長的彈體使T/D非常小,對照上表slope multiplier會壓得很低,使轉正效應下降
這也是現代坦克不太設計超斜裝甲的原因之一



補充口徑壓制

引用來源
http://forum.worldoftanks.com/index.php?/topic/260481-overmatching/

wot中常常講的轉正比較像是壓制,現實中壓制發生是在彈體直徑比裝甲厚的時候,T/D小於1.00

壓制搭配轉正計算是 裝甲*(1+( (slope multiplier -1)*overmatch factor))

overmatch factor數值為T/D

搭配上面的範例

45mm*(1+( (2.5 -1)*0.5))

所以T-34裝甲對上88mm apc/apcbc大約等於78.75mm等效裝甲


無聊計算下50mm對上T-34

45mm*(1+( (3 -1)*0.9))
所以T-34對上50mm的話大約是126mm等效裝甲,敲門炮這個稱呼名不虛傳(?


關於APC
引用自英文wiki https://en.wikipedia.org/wiki/APCBC

As the war lengthened, target armor became progressively thicker (and sloped) as new tank designs emerged, and early war AP and APHE became progressively less effective. The initial response to this thickening in armor had been to increase the muzzle velocity in newly developed anti-tank guns. However, it was found that steel shot tended to shatter on impact at velocities upward of about 823 m/s (2700 feet/second).

簡而言之,AP在高速下撞擊時會碎掉

Based on this deficiency, a new form of shell was developed which was designated APC (armor-piercing capped). In this form of munition, a cap of softer metal was attached to the tip of an AP (solid) round. The purpose of this cap was many-fold. The cap transferred energy from the tip of the shell to the sides of the projectile, thereby helping to reduce shattering. In addition, the cap appeared to improve penetration of sloped armor by deforming, spreading and “sticking” to the armor on impact and thereby reducing the tendency of the shell to deflect at an angle.

因此而製作APC,一個軟金屬在彈頭可以減少碎掉的機會
另外軟金屬可以幫助穿透傾斜裝甲,透過變型,擴散,"沾黏"裝甲,減少彈體的偏向