ISU-152

[Leviathan]

anybody achieved something with those lumbering hulks?

They sure are pretty persistent and can dish out heavy damage, in multiple ways.

But for their price tag and availability in the crowded support tab they really performed sub-par against Panthers and Tigers. I lost most of the long range engagements where I called them in to stop the T-34 slaughter (oh boy, those things just keep on dying) due to the rounds always missing.

I used the unvetted and 1- star variatns with a buff to 1/2 stars respectively. Maybe it's a micro/works only with three star variants thing? Your experiences?

[Outplayed and Destroyed]

You cant win German tanks with ISU-152(and other tanks) at maximum attack range. Not enough armor for soviet tanks.
Try middle and close attack range with ISU. Seems better.

[Leviathan]

do you remember the hit chance of the ISU's gun? Armour value?

[Gumimeda]

It can kill Tiger or Panther on the medium range quite easy. Try use this beast in Breakthrought attack for destroying bunkers and gun pits.

[[EUG] MadMat]

As already stated somewhere, we've found a bug with the ISU-152 just prior to the beta, causing direct fire HE shell's damages to be half what they should (same issue with Grille) + rounded down.

We've fixed it, unfortunately the fix didn't make it on time fpr the beta.
So, next time you'll see an ISU-152, it will make a minimum of 7 HE damages instead of the actual 3!

[tyke]

They shouldn't perform well against Panthers and Tigers. ISU-152 should be really powerful against soft targets and felt like it was bugged, but even the blast number seems far too low. But how effective against armour should it be? It should be something that's very effective at firing into forests and towns at Infantry and AT Guns and blowing them away, but against tanks?

It could be a fantasy weapon based on propaganda where balanced to be quite effective against tanks. But, despite myths and all the "da beast killaaaaa!!!" stuff, and some games going with that, that isn't accurate depiction, and then should be even more expensive than it is now. What a 152mm round can do to a tank is different to how effective the weapon is for fighting tanks. In reality a 152mm doesn't even need to hit the tank to knock it out of action but can land about 20 metres away and still seriously damage the tank.
Problem with the real ISU-152 and putting it in a direct engagement with enemy tanks is that it has terrible accuracy, you have to load 2 piece 40kg shells, have no tracer and can't see anything from the smoke of firing the massive gun and said 40kg shells anyway, and so on.

As Askey writes in complete Organisational and Statistical Analysis, and Military Simulation, Volume I Project Concepts and General Structure, and Analysing Weapon System Effectiveness, Part 2 Methodology for Calculating a Weapon System's or Database Unit's Overall Combat Power Coefficient (OCPC), page 103:

An important factor not yet considered within either the RF factor (Rate of Fire) or RFE factor (Rapidity of Fire Effect), specifically in relation to MFMs (Mechanised Fighting Machine), is the reduction in rate of fire due to having ammunition with separate warhead and charge. 218 This is particularly critical in tanks and assault guns, with very limited available space and hence only one loader.

During WWII most AFV ammunition came in one piece, so the loader could pick up and load the whole round in one go. For calibres over 110mm the round becomes very head and large. For AFVs with guns over this size there arises the multiple problems of ammunition storage, manhandling such a large round in a small space, and the maximum weight that can be manually lifted. One way to reduce the problems related to excessively large rounds is to load the warhead (shell) and propellant (the charge) separately. This increases the numbers of rounds which can be stored and reduces the load on the loader. It also results in a severe reduction in the rate of fire because the loader has to effectively locate ammunition and load the gun twice per round fired. In addition they may have to 'ram' the shell to make room for the charge. Separate ammunition is common in medium and heavy artillery, but these weapons have a large crew. In these cases several crewman can lift and load each shell and charge, additional crewmen can ram the shell if required, and ammunition stowage is not a problem with yet more men bringing ammunition forward to the weapon. For artillery the normal RF factor already effectively includes separate ammunition in larger calibre weapons.

MFMs with separate ammunition and only one loader have their RFE factor multiplied by 0.8, and MFMs with separate ammunition and two loaders have their RFE factor multiplied by 0.9, to take account of this effect.

The only significant AFVs in WWII which suffered from this effect were the IS-2 with a four man crew, and SU-152, ISU-122, ISU-152 and Sturmpanzer IV with five man crews.219 All these AFVs were direct fire weapons designed primarily for the assault role.220 This goes same way to explaining why combat accounts of these vehicles successfully surprising and engaging multiple enemy tanks are non-existent. Most major tank, assault gun and tank destroyer types in WWII, have combat accounts of a single AFV inflicting damage on numerically and possibly qualitatively superior enemy AFVs. This is often due to surprise, ambush or some similar tactical reason. In these situations a reasonable rate of fire is essential because the firer needs to inflict maximum damage on multiple targets in minimum time (i.e. before they can recover). The firer needs a lot better than around two rounds per minute, which was common in WWII AFVs with separate ammunition.221 This is also one of several reasons why these apparently powerful vehicles had relatively poor kill ratios against enemy AFVs. It should be said however that their kill ratio against dug in defences (where they could stand off at medium range) was good, and this is what these vehicles were primarily designed for.

Other factors which can dramatically affect rate of fire are: the tank commander doubling as the loader or gunner, the presence of a turret basket (both factors included in Fire Control Effect (FCE) below), and the design of the ammunition stowage in the AFV. Ammunition stowage layout and design is not specifically factored into out MFM OCPC calculations. Generally tanks with smaller internal volume have reduced efficiencies in this area. For example, in the IS-2 a portion of the ammunition propellant (charge) was stored in boxes such that the box roofs became the turret floor. When opened, the loader and other turret crew had to side step open ammunition boxes to move around the turret. At the same time the gun rotated above the loader, independent of his orientation, as there was no turret basket. Given all these factors, and its two piece ammunition, it is not surprising the IS-2 had such a low rate of fire.222

218 The QJM model does not include a factor for separate warhead and charge in Mobile Fighting Machines (MFMs).
219 The KV-2 also qualifies with separate ammunition. However the KV-2 had a crew of six so it could have had up to three loaders if needed in its excessively large turret. In this case normal RFE values apply.
220 The Sturmpanzer IV was purely an assault weapon with a short 15cm L/12 howitzer, and it never deliberately used to attack enemy tanks. The Soviet AFVs mentioned were all considered capable of engaging enemy armour was required, but their designs were not optimized for combat with enemy tanks.
221 T.Bean, W . Fowler, Russian Tanks of WWII, Ian Allan Publishing, London, 2002. p. 134. The SU-152 and ISU-152 could fire two rounds per minute, under ideal conditions. The IS-2, ISU-122 had similar rates of fire.
222 There are also unconfirmed reports that the 122mm D-25T Model 1943 gun on the IS series had to be lowered to a roughly horizontal position in order for the warhead and charge to be loaded. The gunner would then elevate the gun onto target after each round. However, the primary basis for this is that some German troops reported that the gun was lowered after each round. In late 1944 the Soviets introduced an improved breach for the 122mm D-25T gun: Among other things, this may have been to fix this problem.

The 7th or 8th book in the series will be focused on the Relative Overall Combat Power of forces later in WWII so there'll be indepth analysis of these weapons when and if that comes out.
But, as he states, the ISU-152, SU-152, ISU-122, and IS-2 overall performed poorly against enemy tanks.
They are potentially powerful weapons with big guns and thick armour and all those milimetres that people like to obsess about and focus on all the milimetres of this and milimetres of that and what these milimetres do to those milimetres, but there are a lot of other aspects to what determines how effective a weapon system is in combat. In some tactical situations those big guns and thick armour can produce neat results and all sorts of weapons can do neat things and perform above their average, but if you take the average of how these weapons performed as a weapon system then ultimately they shouldn't perform particularly well against enemy tanks. However overall they should in practice be really effective at destroying enemy defensive positions.

[Leviathan]

Originally posted by EUG MadMat:

As already stated somewhere, we've found a bug with the ISU-152 just prior to the beta, causing direct fire HE shell's damages to be half what they should (same issue with Grille) + rounded down.

We've fixed it, unfortunately the fix didn't make it on time fpr the beta.
So, next time you'll see an ISU-152, it will make a minimum of 7 HE damages instead of the actual 3!

good to now! It will be a very different beast then

[Leviathan]

Originally posted by XxPu$$yD35tR0y3RxX:

They shouldn't perform well against Panthers and Tigers. ISU-152 should be really powerful against soft targets and felt like it was bugged, but even the blast number seems far too low. But how effective against armour should it be? It should be something that's very effective at firing into forests and towns at Infantry and AT Guns and blowing them away, but against tanks?

It could be a fantasy weapon based on propaganda where balanced to be quite effective against tanks. But, despite myths and all the "da beast killaaaaa!!!" stuff, and some games going with that, that isn't accurate depiction, and then should be even more expensive than it is now. What a 152mm round can do to a tank is different to how effective the weapon is for fighting tanks. In reality a 152mm doesn't even need to hit the tank to knock it out of action but can land about 20 metres away and still seriously damage the tank.
Problem with the real ISU-152 and putting it in a direct engagement with enemy tanks is that it has terrible accuracy, you have to load 2 piece 40kg shells, have no tracer and can't see anything from the smoke of firing the massive gun and said 40kg shells anyway, and so on.

As Askey writes in complete Organisational and Statistical Analysis, and Military Simulation, Volume I Project Concepts and General Structure, and Analysing Weapon System Effectiveness, Part 2 Methodology for Calculating a Weapon System's or Database Unit's Overall Combat Power Coefficient (OCPC), page 103:

An important factor not yet considered within either the RF factor (Rate of Fire) or RFE factor (Rapidity of Fire Effect), specifically in relation to MFMs (Mechanised Fighting Machine), is the reduction in rate of fire due to having ammunition with separate warhead and charge. 218 This is particularly critical in tanks and assault guns, with very limited available space and hence only one loader.

During WWII most AFV ammunition came in one piece, so the loader could pick up and load the whole round in one go. For calibres over 110mm the round becomes very head and large. For AFVs with guns over this size there arises the multiple problems of ammunition storage, manhandling such a large round in a small space, and the maximum weight that can be manually lifted. One way to reduce the problems related to excessively large rounds is to load the warhead (shell) and propellant (the charge) separately. This increases the numbers of rounds which can be stored and reduces the load on the loader. It also results in a severe reduction in the rate of fire because the loader has to effectively locate ammunition and load the gun twice per round fired. In addition they may have to 'ram' the shell to make room for the charge. Separate ammunition is common in medium and heavy artillery, but these weapons have a large crew. In these cases several crewman can lift and load each shell and charge, additional crewmen can ram the shell if required, and ammunition stowage is not a problem with yet more men bringing ammunition forward to the weapon. For artillery the normal RF factor already effectively includes separate ammunition in larger calibre weapons.

MFMs with separate ammunition and only one loader have their RFE factor multiplied by 0.8, and MFMs with separate ammunition and two loaders have their RFE factor multiplied by 0.9, to take account of this effect.

The only significant AFVs in WWII which suffered from this effect were the IS-2 with a four man crew, and SU-152, ISU-122, ISU-152 and Sturmpanzer IV with five man crews.219 All these AFVs were direct fire weapons designed primarily for the assault role.220 This goes same way to explaining why combat accounts of these vehicles successfully surprising and engaging multiple enemy tanks are non-existent. Most major tank, assault gun and tank destroyer types in WWII, have combat accounts of a single AFV inflicting damage on numerically and possibly qualitatively superior enemy AFVs. This is often due to surprise, ambush or some similar tactical reason. In these situations a reasonable rate of fire is essential because the firer needs to inflict maximum damage on multiple targets in minimum time (i.e. before they can recover). The firer needs a lot better than around two rounds per minute, which was common in WWII AFVs with separate ammunition.221 This is also one of several reasons why these apparently powerful vehicles had relatively poor kill ratios against enemy AFVs. It should be said however that their kill ratio against dug in defences (where they could stand off at medium range) was good, and this is what these vehicles were primarily designed for.

Other factors which can dramatically affect rate of fire are: the tank commander doubling as the loader or gunner, the presence of a turret basket (both factors included in Fire Control Effect (FCE) below), and the design of the ammunition stowage in the AFV. Ammunition stowage layout and design is not specifically factored into out MFM OCPC calculations. Generally tanks with smaller internal volume have reduced efficiencies in this area. For example, in the IS-2 a portion of the ammunition propellant (charge) was stored in boxes such that the box roofs became the turret floor. When opened, the loader and other turret crew had to side step open ammunition boxes to move around the turret. At the same time the gun rotated above the loader, independent of his orientation, as there was no turret basket. Given all these factors, and its two piece ammunition, it is not surprising the IS-2 had such a low rate of fire.222

218 The QJM model does not include a factor for separate warhead and charge in Mobile Fighting Machines (MFMs).
219 The KV-2 also qualifies with separate ammunition. However the KV-2 had a crew of six so it could have had up to three loaders if needed in its excessively large turret. In this case normal RFE values apply.
220 The Sturmpanzer IV was purely an assault weapon with a short 15cm L/12 howitzer, and it never deliberately used to attack enemy tanks. The Soviet AFVs mentioned were all considered capable of engaging enemy armour was required, but their designs were not optimized for combat with enemy tanks.
221 T.Bean, W . Fowler, Russian Tanks of WWII, Ian Allan Publishing, London, 2002. p. 134. The SU-152 and ISU-152 could fire two rounds per minute, under ideal conditions. The IS-2, ISU-122 had similar rates of fire.
222 There are also unconfirmed reports that the 122mm D-25T Model 1943 gun on the IS series had to be lowered to a roughly horizontal position in order for the warhead and charge to be loaded. The gunner would then elevate the gun onto target after each round. However, the primary basis for this is that some German troops reported that the gun was lowered after each round. In late 1944 the Soviets introduced an improved breach for the 122mm D-25T gun: Among other things, this may have been to fix this problem.

The 7th or 8th book in the series will be focused on the Relative Overall Combat Power of forces later in WWII so there'll be indepth analysis of these weapons when and if that comes out.
But, as he states, the ISU-152, SU-152, ISU-122, and IS-2 overall performed poorly against enemy tanks.
They are potentially powerful weapons with big guns and thick armour and all those milimetres that people like to obsess about and focus on all the milimetres of this and milimetres of that and what these milimetres do to those milimetres, but there are a lot of other aspects to what determines how effective a weapon system is in combat. In some tactical situations those big guns and thick armour can produce neat results and all sorts of weapons can do neat things and perform above their average, but if you take the average of how these weapons performed as a weapon system then ultimately they shouldn't perform particularly well against enemy tanks. However overall they should in practice be really effective at destroying enemy defensive positions.

Interesting. I always had the ISU line marked as a heavy tankhunter. I think it comes from the common categorization of that vehicle. From the Panzer General series onward in quite every game I played it has always been flagged as an assault gun with impressive AT capabilities ,and much more akin to tank hunters like the Jags Tiger than- let's say the KV-2. I remember that back in Combat Mission Barbarosse/Berlin it performed very good against even the heaviest German tanks as well. This series always served as a benchmark for realism in my books, although the more you look the more flaws and abstrations you'll find.

Anyway. Some very interesting points you make here. All the more as those seem quite well depicted in-game- after the HE fix at least.

[Toppopia]

I know this isnt the best reference but in War Thunder the ISU-152 and any tank that shoots 152mm shells wrecks tanks with just its HE shell. Its been a while since I played but I remember it could even kill Tigers occasionally when you hit the turret of a Tiger H1. Anything with thicker armour/sloping like a Panther though and it stopped being effective but all smaller tanks would be insta-killed by this monstrosity.

[Leviathan]

Citing games to illustrate game balance and mechanics is fine. But it doesn't prove anything but the fact that it was working like that in a game.

I remember back in CM:Barbarossa Berlin I had great fun just by setting up a battle with a single ISU or KV-2 then going hunting for light tanks just using HE rounds...after MadMatts confirmed HE is going to be fixed I might be doing the same thing in SD 2 :D