RoflSeal

IS-2 (All Modifications) - Questions, Information, Gameplay

is2m_berlin.jpg

 

IS-2 model 1944 was an improvement over the earlier IS-2 model in terms of better ballistic shape of the hull. The hull of the IS-1 and IS-2 model 1943 were based of the hull of the KV-13 prototype hence they included a step which had an area of little slope making it vulnerable to the 7.5cm Kwk42 from 1.5km and the 8.8cm Kwk 43 from over 2km away. IS-2 removed this weakpoint and instead had a 100mm sloped glacis at 60 degrees. An extract of a report to GABTU in late August 1944 outlined the effectiveness of the IS-2s armor against German weapons.

 

1. The armor

The front hull of the IS is flatter (compared to the previous one), made of high hardness steel . The upper armour -100mm/60° cannot be perforated with German 75mm and 88mm 1942 and 1943 models, with an initial velocity of 1000m/sec.

The lower part of the front hull can be pierced in case of a hit at 90° with piercing ammo:

a) 75mm model 1942 gun with an initial velocity of 1000 m/s from 900 meters.
b) 88mm model 1943 gun with an initial velocity of 1000 m/s from 2500 meters.
c) 88mm model 1936 gun with an initial velocity of 810 m/s from 100-300 meters.

The front slopes of under-turret box, with 100mm high hardness steel in frontal engagement, cannot be pierced with the aforementioned guns.

The front part of the turret, made with high hardness steel and a thickness of 130mm can be pierced via a perpendicular hit with piercing rounds:

a) 75mm model 1942 gun with an initial velocity of 1000 m/s from 1100 meters.
b) 88mm model 1943 gun with an initial velocity of 1000 m/s from 3000 meters.
 

 

An improvement but it would require further redesigning in the form of IS-3 and IS-4 to grant frontal immunity from the German high-power guns

 

Supposedly some of the late production variants had Kotins loading assisting device which increased the rate of fire to 4-6 rpm.

 

The 122mm D-25T was an incredibly powerful weapon. Even if it a shell didn't penetrate, due to the weight, the impact could cause spalling on the inside. The BR-471 AP/HE round could knock out a Panther had 700-1000m away if facing frontally and a Tiger at around 2000m. In 1945, the BR-471B APBC/HE round was introduced meaning that the Panther and Tiger were vulnerable at all practical combat ranges.

 

mHVJS6G.png

 

Crew: 4

Weight: 46 Tonnes

Length/w gun: 9.09 m

Width: 3.09m

Height: 2.73m

Engine: 12-cyl. diesel model V-2 520hp

Speed: 37km/h

Range: 240km

Armament: 122 mm D-25T, 1x 7.62 Coaxial machine gun 1x 7.62 MG in a ball mount on the rear turret, 1x 12.7 Anti Aircraft machine gun, 1x 7.62 MG in a mount next to the driver

Elevation: -3° to +20°

Turret Traverse: 15deg/sec

 

 

 

Armor Schematic

[spoiler]

is2schemeofarmour2.jpg

[/spoiler]

 

Penetration data of 122mm APBC from Annex A of MN/388/01

8TBzn6M.png

Edited by wotertool
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'Dat front plate.

 

Shame it looks like a big shot trap though...

Edited by TheManYouFear
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this is going to create whine from the Tiger and Panther drivers, because the Soviet Union apparently had bad tanks which were rotflstomped at 3miles away.

 

And a excellent topic Rolfseal:D, lots of info:)

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Another good post by RoflSeal as usual.

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6CMXQxf.png

 

The first variant of the IS-2. Almost immediately after IS-1 was put into production, a larger weapon was required.

a) The T-34 was being upgunned to the 85mm which would increase demand for 85mm barrels and shells

b) As with the KV-1, if the medium tank and heavy tank had the same armour defeating performance, the point of the heavy tank was being called into question.

c) The 85mm was shown to be ineffective against the Tiger frontal armor from over 1km away and completely ineffective against the frontal glacis of the Panther.

 

The two guns on that the design bureaus narrowed down to were the 100mm S-34 and the 122mm A-19, with the 122mm gun being chosen due to nearly identical A/T performance, superior HE shell and most importantly availability (the one thing the Red Army never had a short supply of were 122mm gun barrels and ammunition).

And thus the IS-2 was authorized to enter production on the 31st December 1943 and IS-1s were gradually refitted with 122mm cannons. The first versions of the D-25T had the screw breach from the A-19, which was later upgraded to a semi-automatic semi automatic sliding breach, increasing the rate of fire to 3 rpm.

 

Initially uses of the IS-2 were pretty aggressive and hence they suffered some unnecessary losses in the spring of 1944. However, lessons were learned in time for Operation Bagration and the subsequent destruction of German Army Group Center where the IS-2 played a pivotal role in achieving the breakthrough and in August 1944, IS-2 model 1943s of the 71st IHTR along with T-34s of the 53rd and 52nd TBr bled dry a Panzer counter attack led by King Tigers of the 501st Schwere Panzer Abteilung directed at the Sandomierz Bridgehead, taking nominal losses.

 

It was also during this time that the frontal weakspot caused by the step in the IS-2's armor was discovered which made it vulnerable to the high-power 88mm and 75mm Kwk 43 and Kwk 42 and also the 88mm Kwk 36. In IS-2 model 1944, this weakspot was eliminated.

 

3caKiLF.png

 

Crew: 4

Weight: 46 Tonnes

Length/w gun: 9.09 m

Width: 3.09m

Height: 2.73m

Engine: 12-cyl. diesel model V-2 520 hp 

Speed: 37km/h

Range: 240km

Armament: 122 mm D-25T, 1x 7.62 Coaxial machine gun 1x 7.62 MG in a ball mount on the rear turret.

Elevation: -3° to +20°

Turret Traverse: 15deg/sec

Ammo Capacity : 28 rounds

 

Armor Schematic

 

[spoiler]

is2_armor_scheme.gif

[/spoiler]

Edited by RoflSeal
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Is this the one with the 30-second reload?  Harsh.  I wonder if they'll keep that for ground forces HB/FRB.

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Is this the one with the 30-second reload?  Harsh.  I wonder if they'll keep that for ground forces HB/FRB.

Testing revealed the ROF could be as high as 4-6.

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Testing revealed the ROF could be as high as 4-6.


Depends on the breach used. I think in May-June 1944 the semiautomatic breach was beginning to be introduced and older ISs were gradually refitted with it.

Edited by RoflSeal
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Depends on the breach used. I think in May-June 1944 the semiautomatic breach was beginning to be introduced and older ISs were gradually refitted with it.

 

Maybe that will be an unlockable upgrade for the IS-2.

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Did the Is-2 (can't recall) have an issue with reloading the 122mm? You had to point the barrel downward to reload, and then reacquire your target again.

Edited by cryotech9020

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this is going to create whine from the Tiger and Panther drivers, because the Soviet Union apparently had bad tanks which were rotflstomped at 3miles away.

 

And a excellent topic Rolfseal:D, lots of info:)

Yeah, Tiger won the war lol.

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http://www.youtube.com/watch?v=RDIU7TKZDTs&list=PLjhgvLxrPCvA_WKFUmUZcswll9CeQjIiD&index=20

:salute:

Nice video i can't wait to drive this tank in the game :Ds

but why do Russians use wood on one side of their tanks :dntknw:   

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Unditching beam.

Can be used to make a tank become unstuck in mud and also...

 

Jeremy+Clarkson+is+a+smart+man_9587ad_48

Edited by RoflSeal
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Unditching beam.

Can be used to make a tank become unstuck in mud and also...

 

Jeremy+Clarkson+is+a+smart+man_9587ad_48

Made me laugh so hard when I saw that episodexD.

 

Also whats the effective armour thickness on the front upper glacis, lower glacis and front turret on the 1944 model?

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If we put the numbers through WWII Gunnery

 

Front upper glacis 100mm cast armor at 60 degrees 

vs 75mm APCBC = 297mm effective

vs 88mm APCBC = 274mm effective

vs 128mm APCBC = 223mm effective

 

Lower glacis 100mm cast armor at 30 degrees

vs 75mm APCBC = 116mm effective

vs 88mm APCBC = 110mm effective

vs 128mm APCBC = 96mm effective

 

Front upper glacis 90mm Rolled armor at 60 degrees (IS-2 m1944 produced in the UTZM factory)

vs 75mm APCBC = 305mm effective

vs 88mm APCBC = 285mm effective

vs 128mm APCBC = 237mm effective

 

Front lower glacis 90mm Rolled armor at 30 degrees (IS-2 m1944 produced in the UTZM factory)

vs 75mm APCBC = 109mm effective

vs 88mm APCBC = 105mm effective

vs 128mm APCBC = 93mm effective

 

Turrets for both are probably at minimum ~100mm effective ,but since they are rounded, if you strike at a high angle, the round can ricochet

Edited by RoflSeal
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Unditching beam.

Can be used to make a tank become unstuck in mud and also...

 

Jeremy+Clarkson+is+a+smart+man_9587ad_48

thanks for the info  :)s

Jeremy Clarkson rules :good:

Edited by Blackeagle99
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If we put the numbers through WWII Gunnery

 

Front upper glacis 100mm cast armor at 60 degrees 

vs 75mm APCBC = 297mm effective

vs 88mm APCBC = 274mm effective

vs 128mm APCBC = 223mm effective

 

Lower glacis 100mm cast armor at 30 degrees

vs 75mm APCBC = 116mm effective

vs 88mm APCBC = 110mm effective

vs 128mm APCBC = 96mm effective

 

Front upper glacis 90mm Rolled armor at 60 degrees (IS-2 m1944 produced in the UTZM factory)

vs 75mm APCBC = 305mm effective

vs 88mm APCBC = 285mm effective

vs 128mm APCBC = 237mm effective

 

Front lower glacis 90mm Rolled armor at 30 degrees (IS-2 m1944 produced in the UTZM factory)

vs 75mm APCBC = 109mm effective

vs 88mm APCBC = 105mm effective

vs 128mm APCBC = 93mm effective

 

Turrets for both are probably at minimum ~100mm effective ,but since they are rounded, if you strike at a high angle, the round can ricochet

That looks pretty beastly, thanks:)

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If we put the numbers through WWII Gunnery

 

Front upper glacis 100mm cast armor at 60 degrees 

vs 75mm APCBC = 297mm effective

vs 88mm APCBC = 274mm effective

vs 128mm APCBC = 223mm effective

 

Lower glacis 100mm cast armor at 30 degrees

vs 75mm APCBC = 116mm effective

vs 88mm APCBC = 110mm effective

vs 128mm APCBC = 96mm effective

 

Front upper glacis 90mm Rolled armor at 60 degrees (IS-2 m1944 produced in the UTZM factory)

vs 75mm APCBC = 305mm effective

vs 88mm APCBC = 285mm effective

vs 128mm APCBC = 237mm effective

 

Front lower glacis 90mm Rolled armor at 30 degrees (IS-2 m1944 produced in the UTZM factory)

vs 75mm APCBC = 109mm effective

vs 88mm APCBC = 105mm effective

vs 128mm APCBC = 93mm effective

 

Turrets for both are probably at minimum ~100mm effective ,but since they are rounded, if you strike at a high angle, the round can ricochet

 

Hey... are you a fokkin military engineer or what?  8/s

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Penetration with the 122 and bunch of other guns for comparison.

probivbaemost.gif

Edited by t___a
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The 122mm D-25T was an incredibly powerful weapon. Even if it a shell didn't penetrate, due to the weight, the impact could cause spalling on the inside. The BR-471 AP/HE round could knock out a Panther had 700-1000m away if facing frontally and a Tiger at around 2000m. In 1945, the BR-471B APBC/HE round was introduced meaning that the Panther and Tiger were vulnerable at all practical combat ranges.
The D-25T isn't that great, while it's HE-Shell are great, the AP-Capabilities are lacking, especially if you keep in mind that it lacked a APC-Type shell and therefore suffered against hardened steel. Also please keep in mind that the IS-2 Model 1944 Tank you value so highly in fact is not the Match for the Tiger I but the Tiger 2.
 

The penetration table (numbers in the quote) you posted seems questionable, as the first part seems to be calculates using the °30 pen-values as 90° and then calculating vs. effective armor and using a modifier for the hardened armor.

 

This leads to something "weird": In fact, German Tanks had face-hardened armor on most tanks, which while being great against soviets who did field APC or APBC shells only on rare occasions  was actually a weakness against the allies good apc/apcbc shells - most likely they rated soviet tanks as more of a danger. (kinda understandable, especially given the geography). Also, Germans *mostly* counted on abcbc-he and apcr shells which perform better against hardened steel, what makes the coice from soviets kinda odd.

 

Supposedly some of the late production variants had Kotins loading assisting device which increased the rate of fire to 4-6 rpm.

Under training conditions.

 

 

Penetration data of 122mm APBC from Annex A of MN/388/01

FYZoi3X.png

This chart seems to be pretty much spot on, however not for the shell/gun in question but for the BR472 fired by the D-74 field gun (don't know if T-10 also fired them).

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