GUNS_Revision_v01

[kraut1]

36 minutes ago, Aed said:

@kraut1  its a _kwk-36.txt  same gun as AA 88mm gun in game..
Can U pls put your gun files with dispersion here? 

The basic mod from 2025 is this:

Weapon-Accuracy-Mod-6Mils-dispersion.zip

In later versions for certain ToW Mods I raised the dispersion of low velocity MG-FF a bit. And for the 37mm AT cannons with very few ammunition (15...30 rounds) maybe without increased dispersion.

[Stonehouse]

1 hour ago, Aed said:

@kraut1  its a _kwk-36.txt  same gun as AA 88mm gun in game..
Can U pls put your gun files with dispersion here? 

Most of the dispersion for vehicles and flak guns etc is given by the bot file used by the weapon. The dispersion for the actual weapon is fairly trivial compared to the possible dispersion in the bot file. Ditto for aircraft turrets. Be aware that modifying a weapon's dispersion impacts all instances where it is used. You will need to do a lot of testing (and I really mean a lot) to ensure that you don't improve one aspect but cause an issue elsewhere. Ditto for the bot files. 

Edited Friday at 11:51 AM by Stonehouse

[Aed]

Interesting findings from this research. Aircraft weapons are defined in their own files with a single unified dispersion parameter for all of them. In practice, it's set to 0 for a cold (not overheated) barrel.

AI-controlled aircraft use the exact same weapon files.

Ground units, however, have separate turret files. For 88mm guns, the dispersion error is built into the aiming logic. For 20mm and smaller anti-aircraft machine guns, there is a separate dispersion parameter. At first glance, it appears to be an averaged value.

This means you cannot simply copy that turret dispersion parameter into aircraft gun configurations. It's simpler and more accurate to calculate dispersion using formulas and tables. Besides, aircraft cannons and machine guns clearly have a non-zero initial dispersion due to their own vibration, and some cannons suffer from rather poor ballistic performance as well.

@kraut1 how did you get 0.344?

UPD: But it turns out that the dispersion is actually built into the aircraft configurations themselves, down to the convergence distance and whether you're firing in bursts or single shots. In that case, I wouldn't touch the aircraft guns dispersion at all.

Edited Friday at 12:26 PM by Aed

[kraut1]

1 hour ago, Aed said:

 

@kraut1 how did you get 0.344?

 

in my last reply of the 2025 discussion I have explained the (rough) calculation.

https://forum.il2sturmovik.com/topic/92101-question-accuracy-of-typical-ww2-plane-armament-machine-guns-automatic-cannons/

As I have mentioned no exact science but I have flown with this mod ca. 110 campaign combat missions with realistic settings and for me it was okay...😁

Edited Friday at 02:17 PM by kraut1

[Hook_Echo]

@Aed I was looking for the hispano in your mod files. I don't see he_020mm_130g_11g_object.txt. Is the hispano not in version 1?

Also could you give me a breakdown of what these numbers mean? I'm trying to figure all this out. I understand shrapnel and mass but the rest is puzzling me. Are there units for these numbers? For ArmorShr we have radius, then velocity, and then something to do with armor and then the damage?

ArmorFoug=0.0,-1,    1,375,    0,750
ArmorFoug=0.4,-1,        0,300   // Убрали пару с броней (было 0,150)
ArmorFoug=0.8,-1,            0,100
ArmorFoug=1.2,-1,            0,60
ArmorFoug=1.6,-1,            0,50

// Осколочное воздействие
ShrapnelQuantity=20
FragmentMass=0.0044
                                                                                                                               
ArmorShr=0.0,403,    4,57,    0,143
ArmorShr=1.0,380,    3,45,    0,115
ArmorShr=2.0,360,    2,30,    0,90
ArmorShr=3.0,340,    1,18,    0,65
ArmorShr=4.1,320,        0,40   // Убрали пару с броней (было 0,9)

[Aed]

Hi, thanks for the question.

1. Hispano in v1
You're right — the Hispano file (he_020mm_130g_11g_object.txt) is not in the first release of the mod. I think i just missed it.

2. What the numbers mean

 No, there are no real-world units (like mm or Joules) in these files — everything is in game units, calibrated internally by the devs. But they follow clear physical logic.

ArmorFoug — blast / HE effect

Format:
ArmorFoug = distance, -1, armor1, damage1, armor2, damage2

distance — from the explosion center (meters)

-1 — unused (it's a placeholder for something else)

armor1 — thickness of armor the blast can penetrate (mm)

damage1 — damage dealt if that armor is penetrated

armor2 — thickness of armor for the second hit (usually 0 for unarmored surfaces)

damage2 — damage dealt if the second armour value is matched

Example:
ArmorFoug=0.0,-1, 1,375, 0,750

At 0 meters:

Blast penetrates 1 mm of armor → deals 375 damage

On unarmored surface (0 mm) → deals 750 damage

At 0.4 meters, only unarmored damage (300) remains

At 1.6 meters, just 50 damage left — blast fades out

ArmorShr — fragment effect

Format:
ArmorShr = distance, velocity, armor1, damage1, armor2, damage2

distance — from explosion center (meters)

velocity — fragment velocity at that distance (m/s)

armor1 — armor thickness the fragment can penetrate (mm)

damage1 — damage if that armor is penetrated

armor2 — armor for the second hit (usually 0)

damage2 — damage on unarmored surface

Example:
ArmorShr=0.0,403, 4,57, 0,143

At 0 meters:

Fragment velocity = 403 m/s

It penetrates 4 mm of armour → 57 damage

On unarmoured surface (0 mm) → 143 damage

At 4.1 meters, velocity = 320 m/s, no armor penetration, just 40 damage on bare skin

The ArmorShr rows describe one fragment. The total fragment damage is this value multiplied by ShrapnelQuantity.

So yes — these numbers are all in game units, but they're tightly coupled to real physics (mass, velocity, armor thickness). We didn't invent them; we recalculated them using Gurney and De Marre equations, and then scaled them into the game's internal system.

Hope that helps. If you want the Hispano file, just let me know.

[Stonehouse]

I don't believe it is 2nd hit but more a comparison for each hit to the armour at the location and if the armour is less than or equal to the value of the amount of penetration then apply that damage.

I also believe that the shrapnel damage is applied individually not as a multiplier. IE 20 fragments are 20 possible locations hit in a sphere around point of impact.

There is also a representation of internal bulkheads etc that reduce the energy of each round as it penetrates.

Edited 8 hours ago by Stonehouse

[Aed]

🔍 You're right about:

1. ArmorFoug and ArmorShr pairs
It's not "first hit / second hit". It's a threshold system:

If the armor at the impact point is ≤ the first value → apply the first damage.

If the armor is ≤ the second value → apply the second damage (which is usually lower, because it's for thinner armor).

The game picks the highest damage value that matches the armor thickness.

So for ArmorShr=0.0,403, 4,57, 0,143:

If the fragment hits 4 mm armour → 57 damage.

If it hits 0 mm (unarmoured skin) → 143 damage.

If it hits 6 mm armor → fragment stops, no damage.

Not "second hit" — just a conditional check based on actual armor thickness at that exact point.

2. Fragment damage is applied individually
You're right — ShrapnelQuantity=20 means 20 fragments are spawned, and each one travels in a different direction. Each fragment does its own penetration check and damage roll. If 10 fragments hit the wing, each one is processed separately. They don't "sum" into one big hit.

3. Internal bulkheads and energy loss
Yes, that's exactly what energyloss does. In the CPlane files we have:

text

energyloss="",true,0.23,1000

0.23 — equivalent armor thickness the fragment must beat to enter the zone.

1000 — energy lost per meter of travel inside the zone.

So when a fragment enters a wing zone, it loses energy as it passes through internal structure. If it hits a bulkhead, the game checks armor again. This is why fragments often stop before reaching the pilot — they run out of energy inside the airframe.

[Hook_Echo]

@Aed @Stonehouse Thank you for the info guys. Very helpful. I unGTP'ed my first files a few days ago. I appreciate your accumulated knowledge.