Postby Pyro » Mon 7 Dec 2015 13:17
Practical Example
Consider two tanks in the topmost bucket: the Leopard 2A4 and the T-80U, being fired upon by a KE round with a penetration of 22 (550mm penetration - a 120 mm US M829 DU APFSDS at 2,000m) (or 560mm penetration - a 125 mm SU BM-32 DU APFSDS at 2,000m). The data that I use for their front face is as follows:
Leopard 2A4
W:AB AC 20
Inferno D bucket average 23
T-80U with K-5
W:AB AC 20
Inferno D bucket average 23
Effect: Same damage. The damage is given by the Maps in 237: TGameplayArmeArmureContainer, calculated by the first term in the formula to be 5.4
The criticals are now rolled. The first step is to correct to the maximum armour value on each face - the second term in the formula:
Leopard 2A4
Maximum armour: 30
Correction for maximum armour: -0.7
Cumulative damage: 4.7
T-80U with K-5
Maximum armour: 28
Correction for maximum armour: -1.1
Cumulative damage: 4.3
The next step is to randomise. So this says, assume you've hit the most protected spot on the target, can you kill it? If so, we don't have to check for specific location hits. The randomisation is from -2.3 to +1.0 and is a skewed bell curve (skewed because of the effect of a randomised angle of attack; i.e. it may not be square on). Assuming a dice roll of 48% (-0.2) we get this:
Leopard 2A4
Correction for randomised attack: -0.2 (48%)
Cumulative damage: 4.5
T-80U with K-5
Correction for randomised attack: -0.2 (48%)
Cumulative damage: 4.1
Still no KO, because the value has not exceeded 10. So now we randomise the hit location. Here are the possibilities:
Leopard 2A4
Turret hit, mantlet: armour 24, damage adjustment 0.6 (5% chance to hit this location)
Turret hit, centre: armour 30, damage adjustment 0.0 (5%)
Turret hit, centre on gunsight*: armour 28, damage adjustment 0.2 (5%)
Turret hit, outer: armour 26, damage adjustment 0.4 (35%)
Hull hit, glacis: armour 24, damage adjustment 0.6 (30%)
Hull hit, lower: armour 24, damage adjustment 0.6 (20%)
T-80U with K-5
Turret hit, upper: armour 12, damage adjustment 2.1 (5% chance to hit this location)
Turret hit, upper ERA**: armour 15, damage adjustment 1.6 (5%)
Turret hit, mantlet: armour 19, damage adjustment 1.0 (5%)
Turret hit, centre: armour 15, damage adjustment 1.6 (5%)
Turret hit, centre ERA: armour 26, damage adjustment 0.2 (5%)
Turret hit, outer: armour 17, damage adjustment 1.3 (5%)
Turret hit, outer ERA: armour 27, damage adjustment 0.1 (20%)
Hull hit, glacis: armour 19, damage adjustment 0.9 (5%)
Hull hit, glacis ERA: armour 28, damage adjustment 0.0 (25%)
Hull hit, lower: armour 9, damage adjustment 2.8 (20%)
*Only the Leopard 2 has a spot for a hit on the gunsight - it is a large noticeable weak spot that you can see in photos.
**ERA - explosive reactive armour, useful mostly against CE (eg HEAT) rounds but also effective against KE. Coverage on Soviet tanks in this period is less than 100%, so I have reflected that using different percentages in locations.
See here how some AFVs (e.g., Leopard 2, Challenger and M1) are quite homogeneous in their armour protection, not varying much from the average. Most tanks however, and all Soviet tanks in this time period, have quite a large variation in armour protection across a particular face. In Inferno, this is modelled quite accurately, so you can notice that tanks such as Leopard 2, Challenger and M1 are KO'd within narrow bands of attacking AP, but other tanks can be KO'd with a hit on a weak location with a much lower attacking AP.
Continuing the example, let's assume a hit on the hull lower (a 20% chance):
Leopard 2A4
Correction for Hull hit, lower: 0.6 (20% chance to hit this location)
Cumulative damage: 5.1
T-80U with K-5
Correction for Hull hit, lower: 2.8 (20% chance to hit this location)
Cumulative damage: 6.9
Now the last term is added, a fixed constant of 4.5. Remember, we added 10 to the formula because it takes 10 to KO. We added 5.5 at the beginning, the first term which is the damage is given by the Maps in 237: TGameplayArmeArmureContainer. Now we must add the 4.5 to make the sum correct. See the discussion under "Formula" above if this is not clear. Once this is done, if the vehicle is not destroyed then a "healing" AddDamages of -10 is added, to bring the HPs back to zero.
Leopard 2A4
Correction for constant: 4.5
Cumulative damage: 9.6 - no KO
Healing damages added: -10
Cumulative damage: 0 (rounded up to zero always by game engine)
T-80U with K-5
Correction for constant: 4.5
Cumulative damage: 11.4 - destroyed
At this point the T-80U is KO'd, but the Leopard 2A4 survived. Had the dice roll been a little luckier, or if the attack occurred at a closer range, the Leopard 2A4 would also be destroyed.
It is a characteristic of the period that Inferno models (1980-1989) that the rise in defensive armour outstripped the rise in attacking power as the decade progressed. Tanks available in 1980 were much weaker compared to the ones available in 1989. This makes it a very interesting period to model. I have built the Inferno mod with the ability to battle with early '80s, mid-80s or late-80s equipment, and I suspect there will be very different tactics and results in each period. I also think the Soviets have the edge in equipment in the early 80s, and NATO in the late 80s, which makes the mid-80s possibly quite evenly balanced.
