leonpoi
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Re: Vehicle Cannon Stats Look Off (HE vs HEAT vs APFSDS)

Thu 17 Jun 2021, 04:47

Something like that would work I think. I like the idea of bonuses for advanced FCS - it’s something I did have for a house rule previous additions. From memory

I agree that some modifier vs HEAT rounds would be the way to go

Also, comparing the Large-Caliber Guns from Tw2k 2.2 and the new addition there seems to be a good match between the Pen and damage values respectively. (I have a screenshot but can't work out how to insert it here because I get an error message saying the file is too large ....)

but e.g.
25mm AP is Dam 5
100mm APDS is Dam 8
120mm APFSDS is Dam 10 and Armour -1
125mm APFSDS is Dam 11 and Armour -1

in 2.2
25mm AP has Pen 13 / 13 / 9 / 3 for the 4 range bands
100mm APDS has Pen 70 / 60/ 50 / 30 for the 4 range bands
120mm APFSDS has Pen 110 / 100 / 90 / 70 for the 4 range bands
125mm APFSDS has Pen 100 / 90 / 80 / 60 for the 4 range bands

So at least for the very large calibers the, roughly, each 10 Pen = 1 Damage and APFS / APFSDS etc rounds have their Pen declining as a function of range. These map to the conversion rules on p110 of the referee manual also if a cross check is needed because armour is not a linear relationship in the new edition.

So, if penalties for HV rounds due to range is something you wanted, you could just map it back to the conversion rules (which would be roughly no penalty for the 1st 2 range bands for 120/125mm, and then -1 at 3rd and between -1 and -2 at 4th range band. So a simple approach would be to say 1st 2 range bands no change and you lose the -1 Armour at more than that. 100mm doesn't map as well, but I suppose you could have the same rule with -1 Armour for > half max range.

Having a look at the rules for composite armour in v2.2 (there's also spaced, ERA, but I'm not looking to be comprehensive) - what is basically does is half the Pen value of HE rounds - it's a bit unclear if this applies to HEAT also, because it's not explicitly mentioned ..... What I think might be easy is to say the -1 Armour for HEAT rounds doesn't apply to CA / CSA armour (which is almost equivalent to your post Ursus Maior, or perhaps make it a +2 penalty so that it's +1 overall (because otherwise APFSDS adjusted for range and HEAT adjusted for CA / CSA would bring you back to the same relative effective again because they'd both lose -1 Armour ..... and what would be the point of that !). Then do a sense check to see if it's going to hit the cannot penetrate threshold for having Dam >= 2+ vs Armour)

So ..... in a nutshell. Perhaps:
APFSDS are -1 Pen at >50% max range (last 2 range bands)
HEAT is +2 vs CA / CSA armour (to keep it simple and not differentiate) and perhaps an extra +1 for ERA

So @Ursus Maior - almost exactly what you said !

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Ursus Maior
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Re: Vehicle Cannon Stats Look Off (HE vs HEAT vs APFSDS)

Thu 17 Jun 2021, 11:17

So ..... in a nutshell. Perhaps:
APFSDS are -1 Pen at >50% max range (last 2 range bands)
HEAT is +2 vs CA / CSA armour (to keep it simple and not differentiate) and perhaps an extra +1 for ERA

So @Ursus Maior - almost exactly what you said !
Yay, lucky me. I confess, I never fully read v2.2 so I did no comparison there. But I forgot to think and write about reduced penetration for AP(FS)DS over longer ranges. I second your suggestion, though, it seems easy to understand and integrate.

What I omitted as well, but I think it goes without saying, is that many of these attributes could be combined: Especially the Soviets, but also Israelis and certain third-parties, upgraded the heck out of obsolescent designs. The sheer amount of T-55 variants is absurd. So, there are tanks with regular armor (pre-1970) that got composite spaced armor with ERA tiles, laser range finders, new fire-control computers, stabilizers, guns and power packs, essentially designing a completely new tank. The Romanian TR-85 is such an example, it was even improved with a rifled gun that shoots APFSDS. In it's core it remains a pimped T-55, though, which has inherent limits and is super-cramped.
liber & infractus
 
leonpoi
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Re: Vehicle Cannon Stats Look Off (HE vs HEAT vs APFSDS)

Thu 17 Jun 2021, 22:54

Cool. From memory in 2.2, for ERA, you could install up to 10 tiles and then you’d have a “number of tiles out of 10” chance on a d10 for a tile to be hit (perhaps on a certain facing i.e. not the rear). If a ERA tile was hit it would be used and therefore future hits had a higher chance of missing the ERA

[edit] - just thinking too on the FCS comment (that there are 2 types of FC available but they are not differentiated in the rules). V2 had 2 separate ways of tracking this 1) weapon stabilisation (none, basic, fair, good) and 2) FC (0, 1, 2, 3, 4). From memory stabilisation allowed you to reduce moving and shooting penalties a bit (fair) or entirely (good) and FC cancelled out a number of range or enemy moving penalties equal to the value.

We are kind of lucky that the penalties for range are -1, -2, -3 and moving target is -1 = max of -4, so if we wanted to go by the same principles it would not be hard. FCS in the new version cancel the -2 for moving, but if we wanted to have more granularity you could have different levels of stabilisation to cancel up to -1 and -2.

Then the next step would be to go through all the vehicles and decide which had what …. But we don’t need to do this because we can just jump onto Paul’s site and use those values (which I’m sure are better than anything I could come up with).

E.g. I would just keep it simple and say FCS assumes stabilisation that cancels moving and then you can have a number of range / target moving penalties cancel equal to the system value. E.g. M60A3 could be FCS(3).

(Edit) - just realised that Paul’s page also lists which vehicles has composite armour also, so the “job” of working it all out is made very simple. There’s not many vehicles in the current version so it wouldn’t take long to make a list. Then, vehicles have a little bit more depth - composite armour, different night vision / thermal capability, weapon stabilisation, FCS ability - which means a vehicle fight has a little more crunch too it but the additional rules don’t make it much more difficult.

E.g.

https://www.pmulcahy.com/tanks/us_tanks.html

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HorusZA
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Re: Vehicle Cannon Stats Look Off (HE vs HEAT vs APFSDS)

Tue 22 Jun 2021, 09:56

I've played loads of 1:300 ultra-modern miniature wargaming so I've dipped into various sources (Challenger, Fist Full of Tows, Armoured Brigade, Steel Beasts, etc.) to rework the armour and penetration model in my game (along with stuff like fire-control systems).
Due to their nature, exact values are hard to come by so I've looked for broad consensus between the different systems to derive at what seems like reasonable approximations. The things I've struggled the most with was how to model the differences between spaced, composite, active and applique armour in regards to chemical energy penetrators and their interactions with things like precursor tips and tandem warheads.
In my system, APFSDS is generally preferred over HEAT in most circumstances except at very long ranges or against thinner-armoured targets due to the enhanced behind-armour effects of HEAT.
 
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Ursus Maior
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Re: Vehicle Cannon Stats Look Off (HE vs HEAT vs APFSDS)

Tue 22 Jun 2021, 10:49

APFSDS absolutely is the ammunition of choice for modern MBT vs. MBT combat, and that's not limited to non-extreme ranges. During the Gulf War a Challenger used a APFSDS round to kill an Iraqi tank over a range of 4,700 m. The 120 mm gun of the M1A1 (or M1IPM) and the Leopard 2 had a battle range of at least 3,000 m during the 80s and 90s (the T2K timeframe). And this supremacy of APFSDS rounds should be reflected in the rules.
liber & infractus
 
leonpoi
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Re: Vehicle Cannon Stats Look Off (HE vs HEAT vs APFSDS)

Tue 22 Jun 2021, 17:20

I’d love to see what you’ve done so far on this
I've played loads of 1:300 ultra-modern miniature wargaming so I've dipped into various sources (Challenger, Fist Full of Tows, Armoured Brigade, Steel Beasts, etc.) to rework the armour and penetration model in my game (along with stuff like fire-control systems).
Due to their nature, exact values are hard to come by so I've looked for broad consensus between the different systems to derive at what seems like reasonable approximations. The things I've struggled the most with was how to model the differences between spaced, composite, active and applique armour in regards to chemical energy penetrators and their interactions with things like precursor tips and tandem warheads.
In my system, APFSDS is generally preferred over HEAT in most circumstances except at very long ranges or against thinner-armoured targets due to the enhanced behind-armour effects of HEAT.

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