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New comparative gun penetration data from Overlord's Blog

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Vlevs #61 Posted 27 August 2012 - 04:11 PM

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View PostZeZergling, on 27 August 2012 - 02:15 PM, said:

HEAT = 2x / 200mm (HEAT isn't affected by caliber; slope effect is always line of sight thickness)

One minor nitpick. In the test I linked HEAT shells were observed to fail to fuse at high angles, like T-54 glacis (60° vertical) with at least 20° side angle.

View PostTodd, on 27 August 2012 - 03:45 PM, said:

So how does normalization actually work IRL? If a plate at 60 degrees resist at least 2.5 times its own thickness then wouldn't E100's upper plate (without normalization) = 2.5x200mm=500mm armor?! In real life that is =) From what I understand bigger caliber = more normalization?
Btw: I wonder why WG doesn't implement improved versions of the 88 and 128 gun. The new guns will have better ammunition which would make them much better at higher tiers. Early 128 PaK could have the low charge, Late KwK the medium charge and Late PaK the huge charge? Same with difference ammunition types, AP, APBC, APCBC (what do they actually mean? :s). Me think great solution to all balance problemos =)

Posted Image
What traditional AP shells tend to do IRL is c). In WoT, e) is in effect. Modern APFSDS rounds tend to do this as well. http://en.wikipedia....i/Sloped_armour

APCBC means armour-piercing capped ballistic cap shell. This is armor-piercing shell that has cap, a blunt buffer of softer metal, added to reduce stresses to shell when penetration begins to prevent shattering the penetrator - a problem at high velocities.  The cap also helps somewhat against sloped armor by increasing friction between armor and shell, which decreased deviation from LoS. Ballistic cap is a light nose cone that decreases aerodynamic drag, but does not play part in penetration. http://en.wikipedia.org/wiki/APCBC

Edited by Vlevs, 27 August 2012 - 04:45 PM.


Orlund #62 Posted 27 August 2012 - 05:14 PM

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View PostTodd, on 27 August 2012 - 03:45 PM, said:

Btw: I wonder why WG doesn't implement improved versions of the 88 and 128 gun. The new guns will have better ammunition which would make them much better at higher tiers. Early 128 PaK could have the low charge, Late KwK the medium charge and Late PaK the huge charge? Same with difference ammunition types, AP, APBC, APCBC (what do they actually mean? :s). Me think great solution to all balance problemos =)

would make too much sense. remember this is WG we are talking about.

drothi #63 Posted 27 August 2012 - 05:25 PM

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View PostLimaBravo, on 25 August 2012 - 04:37 PM, said:

Erm 2 things ... this is a game & this is a game.  I mention this twice cause its such a large issue mentioning it only once doesnt seen suffiecent.

Also only Germans could whine that their central gun being +20% above its RL comparator & make it about how the poor Jerry doesnt get a fair break.  Learn to Play.

Get a job and don´t flame.

XxXSpottedYouXxX #64 Posted 27 August 2012 - 05:42 PM

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Interesting.

mondog #65 Posted 27 August 2012 - 06:01 PM

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Never believe soviet war time data. They made all equipment that wasn't theirs look bad.

A good example was the P47's the US supplied. The data the Soviets gathered was deliberately made to look bad, but if you compare the US and RAF evaluations of the same models they're not only identical but vastly different to the Soviet tests. The same holds true with nearly everything the Soviets tested, German, British or US. The US and UK data is near enough the same, the Soviet data is skewed with inaccuracies, missing key information and generally made to look like what they're testing is bad. Blame Stalin, its no one else's fault.

FreakDC #66 Posted 27 August 2012 - 06:09 PM

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Modern extreme high velocity shells (HEAT and APCR (Sabots) ignore caliber and slope effects due to fluid mechanics that come into play at these speeds.
Armor and shell act like fluids due to the extrem pressure and heat created by an impact at that speeds. So nearly no deflection comes into play and the diameter of the rod penetrator is also not as important (smaller is actually even better)

In WW2 however speed over ~1000 m/s were mostly decremental to gun penetration. Especially in low caliber guns (high armor over match).
Sub caliber HVAP rounds developed to defeat the Panther's 82mm @ 55° upper glacis for US and UK Weapons often shattered on impact.
US test results for the 90mm M3 showed failures to penetrate Panthers upper glacis as did UK tests of the 17 pdr. APDS.
I think "effect of impact and velocity" is the name of that report.
These rounds were able to penetrate more then 250mm of armor @ 0° angle.


View PostVlevs, on 27 August 2012 - 12:19 PM, said:

Since it seems kind of relevant, I'll link some real-world tests here: http://208.84.116.22...showtopic=18562
The link contains penetration trials by Yugoslavian army in the 60s. They tested several guns in their inventory, including PaK 40 and PaK 43 to assess their performance against modern threats. Targets included "old" tanks M4 Sherman and T-34-85, and "modern" tanks, T-54 and M47. Their conclusion? AP no longer cuts it, buy HEAT.

To clarify, my prev post does not imply that Soviet tank engineers didn't know what they were up against. On the contrary, it seems they knew exactly how the PaK 43 (88 L/71) performed, and gave T-44, T-54, IS-3 and late model IS-2 (not in game) glacis that was strong enough to resist 88 L/71 shell. Note that this isn't evident in the game; despite 88 L/71 having slightly less pen than IRL it performs better than IRL against these plates because devs chose to implement slope normalization the wrong way around - in practice, 60° plate resist slightly more than its LoS thickness of 2x. In WoT the factor is only 1,7x, so the devs for some reason nerfed Soviet armor by the mechanics. Go figure.
WW2 era HEAT was much worse then APCR or even APCBC until you get into very large calibers. The 88's HEAT rounds penetrated roughly 90-100mm of armor at 30°. They had trouble with the fuses with high angle of impacts though. Also spaced armor and even wire mesh often defeated the rounds entirely.
They were also quite slow -> inaccurate.

The late Panzerfaust's  large 15cm HEAT rounds could penetrate 200-220mm armor but only at ~50m range because the slow projectile and inaccuracy of the hand held launcher.

Also not only the Russian tanks are sloped. Later war German models front armor would be near impenetrable (even the universal lower glacis weak spot)
and if you read the whole document you would see that they also had to nerf the 100mm, 122mm and 152mm Russian guns penetration values.
An angled King tiger would resist ~260-300mm penetration from the front, with lower front plate hidden, virtually immune to even T10 guns. E-75 front impenetrable, same for Maus and E-100.
And even the lower tiers: Hetzer, JgPz IV, JgPanther immune up to roughly 160-180mm penetration

Edited by FreakDC, 27 August 2012 - 06:13 PM.


ZeZergling #67 Posted 27 August 2012 - 07:12 PM

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View PostTodd, on 27 August 2012 - 03:45 PM, said:

Is there actual
So how does normalization actually work IRL? If a plate at 60 degrees resist at least 2.5 times its own thickness then wouldn't E100's upper plate (without normalization) = 2.5x200mm=500mm armor?! In real life that is =) From what I understand bigger caliber = more normalization?

Btw: I wonder why WG doesn't implement improved versions of the 88 and 128 gun. The new guns will have better ammunition which would make them much better at higher tiers. Early 128 PaK could have the low charge, Late KwK the medium charge and Late PaK the huge charge? Same with difference ammunition types, AP, APBC, APCBC (what do they actually mean? :s). Me think great solution to all balance problemos =)

Slope modifiers are determined by the ammunition type and base armor thickness version shell caliber; the thickness/diameter ratio, where the larger the shell is relative to the armor thickness, the more it overmatchs and is less likely to ricochet and normalisation effects can occur.

Ammo types:

AP: Armor-piercing. Sharp-nosed shell with no cap.

APC: Armor-piercing capped. AP shell with a cap added to the nose to assist in penetration and reduce impact force that could shatter the shell.

APCBC: Armor-piercing capped, ballistic capped. APC shell with a ballistic cap added to improve aerodynamic performance, which translates to improved penetration at longer ranges.
Slope modifiers for APC and APCBC are identical; they just differ in ballistic performance.

APBC: Armor-piercing Ballistic capped. Normally refers to Russian style APBC, which is a blunt nosed AP shell with a ballistic cap added. These have unusual slope effects.

There is also Western style APBC, which is just sharp-nosed AP shell with a ballistic cap added. These appear to have been fairly uncommon; I think there was an experimental shell for the 90mm guns, and post-war there was the M358 APBC-T (APBC with tracer) fired by the 120mm M58 (M103/T110E5 gun).

All of those above shell types could be either solid shot or have a HE filler/buster charge for improved after-armor damage; most shells of 75mm or higher tended to have HE charges in WW2, some more than others.



HEAT is a shaped charge warhead, and contrary to popular myth, it does NOT melt the armor, but forces it aside via pressure. Slope effect is always equal to line of sight thickness, due to the extreme velocity of the metal jet. A simple cosine calculation is all that is required to calculate effective protection versus HEAT.



There's also the rarer shells that used tungsten; they were lighter than normal AP shells and fired at higher velocties.

APCR: Armor-piercing Composite-Rigid. Basically a sub-caliber tungsten core surrounded by lighter and less dense metal.

HVAP: USA term for APCR type shells. AFAIK, they are basically identical in design to APCR.

APDS: Armor-piercing discarding-sabot. Sub-caliber tungsten penetrator surrounded by light metal sabots that hold the penetrator in the barrel, then seperate after it leaves the barrel.
More aerodynamically efficient than APCR, and also better penetration, but APDS suffered severe accuracy problems from uneven sabot seperation; the problems weren't solved until the 1950s IIRC.

Tungsten shells suffered worse slope modifiers than regular AP shells, due to their small caliber resulting in the shell being overmatched by armor thickness fairly easily.
This worsened with APCR, where the lighter metal jacket would cause additional penetration problems.

I don't have much specific information on slope effects for tungsten ammunition, as substantially less testing took place with much more expensive ammunition.
Likewise, I have little in the way of penetration data for tungsten ammunition, and the DeMarre equation doesn't work so well with impact velocities of more than 1200 m/s.




Now, the E-100's upper plate would have been virtually inpenetrable by WW2 guns.

200mm at 60 degrees versus 152mm shell:
AP = 559mm
APBC = 939mm
APCBC = 659mm
HEAT = 400mm


Even the Tiger II's upper hull (and E-100's lower) was basically inpenetrable.

150mm at 50 degrees versus 152mm shell:
AP = 296mm
APBC = 251mm
APCBC = 315mm
HEAT = 233mm

Basically, the only way to penetrate the Tiger II's upper glacis was with a large HEAT shell... nothing else was available at that time.

Vlevs #68 Posted 27 August 2012 - 07:15 PM

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View PostFreakDC, on 27 August 2012 - 06:09 PM, said:

Modern extreme high velocity shells (HEAT and APCR (Sabots)

APCR = Cored round; APDS = Sabot. Sorry, had to correct even as I'm sure that's just an oversight.

View PostFreakDC, on 27 August 2012 - 06:09 PM, said:

In WW2 however speed over ~1000 m/s were mostly decremental to gun penetration. Especially in low caliber guns (high armor over match).
Sub caliber HVAP rounds developed to defeat the Panther's 82mm @ 55° upper glacis for US and UK Weapons often shattered on impact.
US test results for the 90mm M3 showed failures to penetrate Panthers upper glacis as did UK tests of the 17 pdr. APDS.
I think "effect of impact and velocity" is the name of that report.
These rounds were able to penetrate more then 250mm of armor @ 0° angle.

Sorry, but I don't quite follow. So you say that high velocity causes shatter against overmatching plate. Then you say rounds shatter against angled non-overmatching plate, but do not shatter against unangled but highly overmatching plate.

View PostFreakDC, on 27 August 2012 - 06:09 PM, said:

WW2 era HEAT was much worse then APCR or even APCBC until you get into very large calibers. The 88's HEAT rounds penetrated roughly 90-100mm of armor at 30°. They had trouble with the fuses with high angle of impacts though. Also spaced armor and even wire mesh often defeated the rounds entirely.

The tests were made in the 60s with better HEAT technology, and in later post I cited the fuse problem. That HEAT is better is directly from the article:
"Developement of HEAT ammo suitable to be fired from M3A1 gun mounted on SO-90 M-36 is recomended."
"Amount of M431 HEAT rounds in ammo load should be increased, and load of T33 AP be reduced."
"Frontal engagement of the new foreing tanks is to be done only with M431 HEAT round."
"Problem of M431 round failing to fuse at angles more then 60deg is to be fixed with production of domestic HEAT."

View PostFreakDC, on 27 August 2012 - 06:09 PM, said:

Also not only the Russian tanks are sloped. Later war German models front armor would be near impenetrable (even the universal lower glacis weak spot)
and if you read the whole document you would see that they also had to nerf the 100mm, 122mm and 152mm Russian guns penetration values.
An angled King tiger would resist ~260-300mm penetration from the front, with lower front plate hidden, virtually immune to even T10 guns. E-75 front impenetrable, same for Maus and E-100.
And even the lower tiers: Hetzer, JgPz IV, JgPanther immune up to roughly 160-180mm penetration

True. However, In German tanks apart from E-series and Hetzer sloping was usually more moderate 50° (55° for Panther & JP), while a good number of Soviet tanks from T-34 up used steeper 60° angling. In addition, Soviets tend to have sloped sides, while German sides are near vertical. Thus I consider Soviet tanks to lose more on diluted slope mechanics.

I've thought for some time how WoT would be to play if it was more historically accurate. Given its historical 122 mm gun, two IS-4s can't even damage each other. Many tanks were designed to frontally withstand their own guns. Would that make the game more fun? (Sincere question)


Edit:

View PostZeZergling, on 27 August 2012 - 07:12 PM, said:

200mm at 60 degrees versus 152mm shell:
AP = 559mm
APBC = 939mm
APCBC = 659mm
HEAT = 400mm

150mm at 50 degrees versus 152mm shell:
AP = 296mm
APBC = 251mm
APCBC = 315mm
HEAT = 233mm

Looks like you have an error there.

Edited by Vlevs, 27 August 2012 - 07:22 PM.


CoreMaster101 #69 Posted 27 August 2012 - 08:16 PM

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My great friend Сергеи Донтлиемушх found a Top Secret german gun penetartion data table:

Posted Image

FreakDC #70 Posted 28 August 2012 - 01:04 AM

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Caution long post ahead :Smile-hiding:  amazing what you can write on a long train ride :Smile_veryhappy: .

View PostZeZergling, on 27 August 2012 - 07:12 PM, said:

HEAT is a shaped charge warhead, and contrary to popular myth, it does NOT melt the armor, but forces it aside via pressure. Slope effect is always equal to line of sight thickness, due to the extreme velocity of the metal jet. A simple cosine calculation is all that is required to calculate effective protection versus HEAT.
Single warhead HEAT shells of the 40s and even early 50s were easily defeated by spaced armor and were incredibly slow/inaccurate due to the unaerodynamic form with bad stabilization.

Also spinning greatly reduces penetration of the metal stream because the centrifugal force disperses the focused jet.
This is the reason why HEAT rounds only became widely used with decent fin stabilized rounds fired from smooth bore guns.
Only modern technology made rifled barrels more effective at firing HEAT but it's still not common.

A simple cosine calculation only works with solid steel plates.

View PostZeZergling, on 27 August 2012 - 07:12 PM, said:

APDS: Armor-piercing discarding-sabot. Sub-caliber tungsten penetrator surrounded by light metal sabots that hold the penetrator in the barrel, then seperate after it leaves the barrel.
More aerodynamically efficient than APCR, and also better penetration, but APDS suffered severe accuracy problems from uneven sabot seperation; the problems weren't solved until the 1950s IIRC.
These problems weren't solved until (late) into the 60s which is why the T62 and other tanks of that area only used HEAT.
Also APDS gets highly complicated with rifled barrels which made them ineffective over 500m ranges (can't even hit a tank). Also only solved much later.

View PostZeZergling, on 27 August 2012 - 07:12 PM, said:

Tungsten shells suffered worse slope modifiers than regular AP shells, due to their small caliber resulting in the shell being overmatched by armor thickness fairly easily.
This worsened with APCR, where the lighter metal jacket would cause additional penetration problems.

I don't have much specific information on slope effects for tungsten ammunition, as substantially less testing took place with much more expensive ammunition.
Likewise, I have little in the way of penetration data for tungsten ammunition, and the DeMarre equation doesn't work so well with impact velocities of more than 1200 m/s.
Wartime sub caliber tungsten rounds used to shatter on impact with slopes and they were as said before highly inaccurate.
The softer nose broke of on impact and the core got deflected.
This happened even on small angles, which is why many of the German Plates where slightly set back (10°) to shatter incoming rounds.

Spoiler                     

British tests with the 17 pdr. described in "effect of impact and velocity" talk about trouble getting good hits at 300yards :Smile_teethhappy: . Sub caliber ammo ...

View PostVlevs, on 27 August 2012 - 07:15 PM, said:

APCR = Cored round; APDS = Sabot. Sorry, had to correct even as I'm sure that's just an oversight.
Well technically sabots are just the stuff around the core (today usually a long rod penetrator shaped like a dart with fins) that propel the sub caliber round, you can see them falling of here from this APFSDS:
Spoiler                     
That was the point I was trying to make, very small impact surface + very high kinetic energy = fluid dynamics.
That wasn't the case in WW2.

Nice compendium about shell types:
http://www.flamesofw...aspx?art_id=836

View PostVlevs, on 27 August 2012 - 07:15 PM, said:

Sorry, but I don't quite follow. So you say that high velocity causes shatter against overmatching plate. Then you say rounds shatter against angled non-overmatching plate, but do not shatter against unangled but highly overmatching plate.
Exactly! As long as there is no angle involved the round does not shatter but penetrate (even overmatching plates)
E.g. German 50mm APCR fired from the L/60 penetrated 149mm at 100m @ 0° angle but failed to penetrate the 60° angled T-34 armor that was only 45mm. Velocity was ~1180 m/s.

So the 5cm projectile had no trouble penetrating a three times as thick plate as long as it wasn't angled but failed to penetrate 45mm armor (90mm LOS thickness) which it over matched at a high angle.

Spoiler                     

That's what is called the "shatter gap"
Because the rounds could penetrate if they were slower (e.g. further away).
The mechanics behind it are fairly complicated and very confusing effects can occur.
E.g.
A round could penetrate @ 0 to 300m, then fail to penetrate from 300 to 1000m  and then penetrate again from 1000 -1500m solely dependent on impact angle.

Spoiler                     


View PostVlevs, on 27 August 2012 - 07:15 PM, said:

The tests were made in the 60s with better HEAT technology, and in later post I cited the fuse problem. That HEAT is better is directly from the article:
"Developement of HEAT ammo suitable to be fired from M3A1 gun mounted on SO-90 M-36 is recomended."
"Amount of M431 HEAT rounds in ammo load should be increased, and load of T33 AP be reduced."
"Frontal engagement of the new foreing tanks is to be done only with M431 HEAT round."
"Problem of M431 round failing to fuse at angles more then 60deg is to be fixed with production of domestic HEAT."
Your point being? M431 is late 60s 90mm HEAT that could penetrate ~400mm of RHA.
The WW2 88s fired HEAT that penetrated 90-100mm of RHA.

However these late 60s test show that the 88mm L/71 could penetrate more then 200mm of armor (T-54 turret front) with APCBC @ 600m:
Spoiler                     

View PostVlevs, on 27 August 2012 - 07:15 PM, said:

True. However, In German tanks apart from E-series and Hetzer sloping was usually more moderate 50° (55° for Panther & JP), while a good number of Soviet tanks from T-34 up used steeper 60° angling. In addition, Soviets tend to have sloped sides, while German sides are near vertical. Thus I consider Soviet tanks to lose more on diluted slope mechanics.
Well only KT and Maus use 50°, most other Tanks used 55° while the E series was planed with 60°.
"Non angled" armor plates were usually actually slightly angled at 10° or 8° which was enough to cause shatter problems with some ammunition types.

T-34 and T-34-85 used thin armor that was easily penetrated by the "high quality" (high hardness steel caps that did not shatter as easily according to US and UK tests) German APCBC as long as it over matched (7,5cm L/43 guns and above)
While that is true German armor loses more due to missing/wrong armor over match mechanics.
On the other hand Russian guns lose more due to missing/wrong caliber over match mechanics.


View PostVlevs, on 27 August 2012 - 07:15 PM, said:

I've thought for some time how WoT would be to play if it was more historically accurate. Given its historical 122 mm gun, two IS-4s can't even damage each other. Many tanks were designed to frontally withstand their own guns. Would that make the game more fun? (Sincere question)
122mm D25 failed to penetrate the Panther's glacis at combat range when angled a rather small amount (~30° was German standard "Mahlzeitstellung" for tanks) according to wartime tests described by Steven Zaloga, so they ended up using mostly HE :Smile_smile: .

Well realistic combat would never work with WOT. Sight system and map sizes won't work that way.
If you would add bigger maps, realistic view ranges, accuracy, penetration and ROF German tanks would rip apart the allied tanks of the same period of time at long range.

Spoiler                     

View PostCoreMaster101, on 27 August 2012 - 08:16 PM, said:

My great friend Сергеи Донтлиемушх found a Top Secret german gun penetartion data table:
Amazing that they already had computer graphic support back then! But since it's time dated... seems legit :Smile_trollface-3: .

ZeZergling #71 Posted 28 August 2012 - 02:34 AM

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View PostVlevs, on 27 August 2012 - 07:15 PM, said:

Edit:


Looks like you have an error there.

Actually, that's the unusual slope effects of APBC in effect. When APBC is overmatched by armor thickness, it appears to be inferior to AP and APC shell types at high angles.
APBC only starts to become competitive at 60 degree angles when the shell starts to overmatch the armor.

ZeZergling #72 Posted 28 August 2012 - 03:01 AM

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Here's a direct comparison between Overlord's tables, WoT and my best estimates for historically accurate, 0 degree slope and 100 meter range penetration values for each gun:

45mm 20K: Table = 57mm, WoT = 51mm, Best Estimate = 54mm
57mm ZiS-4: Table = 115mm, Wot = 112mm, Best Estimate = 115mm
76mm F-34: Table = 76mm, WoT = 86mm, Best Estimate = 83mm
85mm D-5/ZiS-S-53: Table = 119mm, WoT = 120mm, Best Estimate = 120mm
85mm D-5S-85BM: Table = 143mm, WoT = 144mm, Best Estimate = 150mm
100mm D-10: Table = 170mm, WoT = 175mm, Best Estimate = 180mm
122mm D-25: Table = 165mm, WoT = 175mm, Best Estimate = 170mm

57mm QF 6 Pounder: Table = 83mm, WoT = 105mm, Best Estimate = 105mm
75mm M3: Table = 64mm, WoT = 92mm, Best Estimate = 81mm

50mm L/60: Table = 74mm, WoT = 67mm, Best Estimate = 90mm
75mm L/48: Table = 103mm, WoT = 106mm, Best Estimate = 140mm
75mm L/70: Table = 150mm, WoT = 138mm, Best Estimate = 180mm
88mm L/56: Table = 120mm, WoT = 132mm, Best Estimate = 155mm
88mm L/71: Table = 168mm, WoT = 203mm, Best Estimate = 230mm

Vlevs #73 Posted 28 August 2012 - 10:11 AM

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View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

So Sabots are technically APCDS rounds because they are still composite in nature just a different kind of encasing.
Modern "Sabots" are more different from WW2 sabots then WW2 APCR are different from WW2 APDS because the actual projectile is no longer a lighter sub caliber round but a long rod penetrator.

Well, since the nomenclature specifically differentiates shells of different type of composite construction, please stick to convention for clarity. If you want to differentiate the design of APCR/APCNR/APDS cores, please refer to cores or penetrators. Thank you.

View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

Exactly! As long as there is no angle involved the round does not shatter but penetrate (even overmatching plates)
E.g. German 50mm APCR fired from the L/60 penetrated 149mm at 100m @ 0° angle but failed to penetrate the 60° angled T-34 armor that was only 45mm. Velocity was ~1180 m/s.

So the 5cm projectile had no trouble penetrating a three times as thick plate as long as it wasn't angled but failed to penetrate 45mm armor (90mm LOS thickness) which it over matched at a high angle.

Spoiler                     

That's what is called the "shatter gap"
Because the rounds could penetrate if they were slower (e.g. further away).
The mechanics behind it are fairly complicated and very confusing effects can occur.
E.g.
A round could penetrate @ 0 to 300m, then fail to penetrate from 300 to 1000m  and then penetrate again from 1000 -1500m solely dependent on impact angle.

[tables]

Thanks, I learned a lot about shatter mechanics today. I haven't managed to secure myself a copy of WWII Ballistics: Armor and Gunnery, so these tables are new to me.

View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

Your point being? M431 is late 60s 90mm HEAT that could penetrate ~400mm of RHA.
The WW2 88s fired HEAT that penetrated 90-100mm of RHA.

No particular point there. I just made a quick summary of the article's findings for the people who were curious but didn't want to read through it all.

View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

However these late 60s test show that the 88mm L/71 could penetrate more then 200mm of armor (T-54 turret front) with APCBC @ 600m:
Spoiler                     

That's pretty much the meat of the article - that PaK 43 using APCBC can punch through 200 mm thick turret front at short range, but isn't good enough to stop a wave of attacking T-54s at range.

View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

Well only KT and Maus use 50°, most other Tanks used 55° while the E series was planed with 60°.
"Non angled" armor plates were usually actually slightly angled at 10° or 8° which was enough to cause shatter problems with some ammunition types.

AFAIK Löwe and JPz IV use 50°, and VK4502B might use it as well. Still, even without deflection mechanics difference between 55° and 60° plate is significant.

View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

122mm D25 failed to penetrate the Panther's glacis at combat range when angled a rather small amount (~30° was German standard "Mahlzeitstellung" for tanks) according to wartime tests described by Steven Zaloga, so they ended up using mostly HE :Smile_smile: .

There's a test account of the shell penetrating (unangled ofc) Panther's glacis and engine. Given that Soviet AP shell technology advanced significantly even during late war, it seems likely that while earlier versions struggled with Panther's glacis, later versions could penetrate it. Frankly, that late-issue 122 mm AP would consistently fail against Panther's glacis seem unlikely to me. If AP doesn't work against "primary" hard target and HE works at least decently against all targets, was there any purpose for 122 mm AP then?

View PostFreakDC, on 28 August 2012 - 01:04 AM, said:

Well realistic combat would never work with WOT. Sight system and map sizes won't work that way.
If you would add bigger maps, realistic view ranges, accuracy, penetration and ROF German tanks would rip apart the allied tanks of the same period of time at long range.

Spoiler                     

And here I was thinking we were talking about gun vs armor mechanics instead of military-historical balance. What I meant that given more realistic armor mechanics all tanks would be harder targets to each other. That would require more thinking - as general rule, everyone would be frontally immune to equivalent tanks at range, which would mean much more flanking and weakspot sniping. That isn't necessarily all bad.

View PostZeZergling, on 28 August 2012 - 02:34 AM, said:

Actually, that's the unusual slope effects of APBC in effect. When APBC is overmatched by armor thickness, it appears to be inferior to AP and APC shell types at high angles.
APBC only starts to become competitive at 60 degree angles when the shell starts to overmatch the armor.

That's interesting. Can you give me the equations so I can do some number crunching myself?

Yamaxanadu #74 Posted 28 August 2012 - 10:35 AM

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View PostVlevs, on 28 August 2012 - 10:11 AM, said:

There's a test account of the shell penetrating (unangled ofc) Panther's glacis and engine. Given that Soviet AP shell technology advanced significantly even during late war, it seems likely that while earlier versions struggled with Panther's glacis, later versions could penetrate it. Frankly, that late-issue 122 mm AP would consistently fail against Panther's glacis seem unlikely to me. If AP doesn't work against "primary" hard target and HE works at least decently against all targets, was there any purpose for 122 mm AP then?
90% of shell in IS-2 were HE shells after Russians learned that 122 HE shell could defeat any German tank from any range as long as it hit it. 20 kg of explosive just knock out crew?

Tuccy #75 Posted 28 August 2012 - 10:50 AM

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One idea re. long 88, before PzGr.39/43 came in, long 88 used also either flak PzGr. or PzGr.39/1, both were suboptimal in high velocity guns (PzGr.39/1 to be fired only from guns with less than 500 shots fired for example). Date of the tests seems to be 2nd half of 1943, ie definitely before PzGr. 39/43 came.

Yamaxanadu #76 Posted 28 August 2012 - 11:03 AM

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View PostTuccy, on 28 August 2012 - 10:50 AM, said:

One idea re. long 88, before PzGr.39/43 came in, long 88 used also either flak PzGr. or PzGr.39/1, both were suboptimal in high velocity guns (PzGr.39/1 to be fired only from guns with less than 500 shots fired for example). Date of the tests seems to be 2nd half of 1943, ie definitely before PzGr. 39/43 came.
Well, considering the fact that during Citadel operation over half of new German vehicles (Panthers and Ferdinands) were out 'cause of mechanical failures it's quite possible that part of those completely functional units was captured with full ammunition.

Vlevs #77 Posted 28 August 2012 - 11:58 AM

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View PostYamaxanadu, on 28 August 2012 - 10:35 AM, said:

90% of shell in IS-2 were HE shells after Russians learned that 122 HE shell could defeat any German tank from any range as long as it hit it. 20 kg of explosive just knock out crew?

Shell weight does not equal HE weight. 122 mm shell had up to 3,8 kg of HE.

View PostTuccy, on 28 August 2012 - 10:50 AM, said:

One idea re. long 88, before PzGr.39/43 came in, long 88 used also either flak PzGr. or PzGr.39/1, both were suboptimal in high velocity guns (PzGr.39/1 to be fired only from guns with less than 500 shots fired for example). Date of the tests seems to be 2nd half of 1943, ie definitely before PzGr. 39/43 came.

Interesting. Where can I read more about this ammo? What's the introduction date and are there German or Western tests with it?

Edited by Vlevs, 28 August 2012 - 12:03 PM.


Yamaxanadu #78 Posted 28 August 2012 - 12:02 PM

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View PostVlevs, on 28 August 2012 - 11:58 AM, said:

Shell weight does not equal HE weight. 122 mm shell had up to 3,8 kg of HE.
Usually it's enough to disable vehicle and cripple crew. As long as it hit and hull or turret.

Vlevs #79 Posted 28 August 2012 - 12:18 PM

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View PostYamaxanadu, on 28 August 2012 - 12:02 PM, said:

Usually it's enough to disable vehicle and cripple crew. As long as it hit and hull or turret.

I remember reading that 152 mm HE was a threat even to KT frontally due to its fragile glacis plate, so it seems reasonable that 122 mm HE shell would similarly threaten Panther. However, I have overall poor grasp on what effect HE load of given size has on armor of given thickness on a tank of given size. I've read a bunch of anecdotes, but overall they give rather inconsistent impression, like 122 mm blowing Panther to smithereens on one occasion and doing next nothing in other. Nominal HE penetration is always pretty low, which means HE often relies on non-penetrating hits to score enough damage to disable tank and crew. I realize there's no clear-cut table for non-penetrating HE effect, but I really would appreciate a good reference on that.

Yamaxanadu #80 Posted 28 August 2012 - 12:27 PM

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View PostVlevs, on 28 August 2012 - 12:18 PM, said:

Nominal HE penetration is always pretty low, which means HE often relies on non-penetrating hits to score enough damage to disable tank and crew.
Yes, basically HE shell do not penetrate but rather send "waves" through all parts of vehicle and destroy some in process. Additionally WW2 tanks was not protected from air pressure of HE.





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