T33 was reheat treated M77 and that actually may have cause it’s shattering issues. Here’s a chart I have showing AP vs APC and AP outperformed APC against 0 degree and 30 degree plates. APC retained its energy better due to the ballistic caps.
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Yes, early solid shells like M77 lacked caps or ballistic caps, but the T33 did have a ballistic cap.
Interesting. If I didn’t make any mistakes reading this graph, a capped round and an uncapped round with the same 0º pen also end up with the same 30º pen. In-game that’s not the case, generally speaking uncapped rounds have worse 30º slope modifiers.
Yeah, I know. My point is AP generally outperformed APC, unless the AP round shattered like T33. If the AP rounds had ballistic caps, they would outperform APC at all ranges.
AP actually has slightly better slope modifiers than APC.
These are not slope modifiers themselves, and while the ‘a’ value is generally lower at the 30º range, the ‘b’ value is noticeable higher, which means that against undermatched armor the AP round will perform worse, and better against overmatched armor.
Using Desmos we can determine that the AP and APC rounds end up with the pretty much the same 30º slope modifier at a T/D ratio of 1.3347, with AP being better if below, and worse if above. WarThunder uses D/T instead, so that would be basically 0.75 in-game. Red line is AP, blue line is APC, as seen from the respective 30º formulas on the top left.
Using 90 mm early M82 APC(BC) and T33 AP(BC) in-game, T33 has a higher 30º slope modifier compared to early M82 at point blank, with 175/132 mm and 173/133 mm of pen respectively at 0º/30º, although T33 will gain the advantage as the penetration decreases. Using the value of 1.3347 and the respective 1.2909 slope modifier, the 30º slope modifier is the same for M82 and T33 once their 0º penetration reaches roughly 155 mm, with 120 mm of 30º penetration for both rounds. I confirmed this using the T-54 (1947)'s UFP, which is 120 mm thick, and using it in protection analysis at 30º gave 155 mm of effective protection for both T33 and M82.
With the US 76 mm cannon, the break even 0º penetration is 130.95 mm, and basically the same for the US 75 mm, at 129.22 mm. However with these cannons the APC round just has massively improved penetration over the uncapped AP round, so the APC ends up with always higher 30º pen at all distances and this comparison becomes a bit pointless, which is why I used T33 and early M82 in my comparison as they have very similar flat penetration values
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Thats a good point. I only calculated the modifiers for 1 T/D and didn’t take the exponent into account.
I think in that case it’s because US APC kinda sucked. They appear to be designed to defeat FHA rather than to retain good penetration over AP at 30° impact angles.
76.2mm M79 is superior in penetrating a Tigers front plate even at 30°.
Had the Tiger used FHA however, then the M62 would be effective at much longer ranges compared to the M79.
To an extent, sure but even if you compare it to 75mm PzGr 39/42 DeMarre to the same velocity, M72 would out perform it by around 10mm.
I would like to hear from a community leader why this entire discussion isn’t a violation of new forum rule 3.6: ““reporting game bugs, errors, or other flaws is not permitted.” Seems to be a pretty flagrant violation. (Link)
I don’t want to stop the conversation, just wanting clarification before I risk my community rating participating as a community member in discussions like this.
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Gaijin has a very spotty track record when it comes to modelling shell shattering. Even before the calculator was implemented, Gaijin still gutted the T33s flat pen to realistic standards because of histroical accuracy. But, despite a bible worths of information made on the forum and suggestions the sloped pen was never touched on. The 90mm does seem very much under lock and key because Gaijin has very much deemed it ‘historically accurate’.
Anyways, the other issue is that only Soviet APHE is allowed almost borderline absurd sloped performance. If other nations were allowed usuable sloped performance, tanks like the T-44 wouldnt be such a balancing nightmare.
In a sense, it seems that soviet midtiers was specifically designed to have this ‘gimmick’ of superb sloped performance. Having uncapped AP shells creep over the soviet gimmick is completely unacceptable. After all this is what makes soviet shells ‘unique’.
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One question, which tanks had face hardened armor? Supposedly the hull front of the tiger 1 was not from FHA? And also the T34 were not made with FHA?
The Germans were really the only ones who used FHA. It works best against impacts of relatively low obliquity (such as with vertical armor plates). However when impacted at an oblique angle such as when you use sloped armor even if the harder front blocks the shell through ricochet or shatter the kinetic energy of the impact has a tendency to cause the softer rear to fly off as internal spalling.
As an (extreme) example, the French battleship Dunkerque had face-hardened armor on her turret tops to protect against AP bombs from aircraft, which meant that when Hood bounced a 15" shell off the top at Mers-el-Kebir the resulting spalling was bad enough to ignite the powder stored in that side of the turret, killing the crew from asphyxiation, as well as completely disable the right-most gun, only the internal bulkheads keeping the guns and crew in the left side of the turret safe.
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Both Pz III and IV used FHA for most of their armor. Probably the Pz II as well.
T-34 and IS tanks had HHA, while pretty much any other tank used RHA or CHA.
80mm FHA should protect against medium velocity 75mm AP projectiles so APC enabled Shermans to destroy Pz IVs even at long range.
A 100mm FHA plate would probably also protect against high velocity 75/76mm AP shells except from the 17pdr.
So 76mm APC was pretty much only required, had either Tiger or Panther used FHA for their 100mm thick armor plates. Since they didn’t, M79 AP was the superior shell.
90mm M82 is the same story. It’s pretty much inferior against any known target compared to M77, unless a vehicle had used >100mm FHA plates.
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I think Japan also used them for their tanks. Certainly for armor plates inside planes, afaik.
So not even the most initial tigers had the heat treatment on the front of the hull?
The armor on the early US M2 series light tanks was also FHA, and possibly on the M2 Mediums. The M3 series tanks more or less has transferred over to high to medium hardness plates depending on thickness.
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Never heard anyone talk about something like that. Since the Tiger is quite a popular tank in media and literature, I’m sure I would have stumbled upon such claim.
I think 80mm is the maxium thickness of German armor to be face hardened during the war.
Ok, thanks, so the ones with the hardened outer shell were pz 3 and 4, but until the last models? Or just the initial and intermediate models.
I think they used FHA until the very last models of the Pz IV. Not sure about the H but the J certainly didn’t use FHA at that point, since the J was an effort to speed up production and lower the costs as much as possible.