Can we discuss about the bombs mechanic KFG?

[the Baron]

I will try to make this as short as possible.

ATM, there is only one simple rule related to bombs. The damage value is related to penetration value. The higher the damage the higher the penetration value and vice versa.

Well this makes impossible to diferentiate AP from HE bombs.

As one example let's say we are comparing 1000lb AP to 1000lb HE bombs.

- If i gave the AP more damage value, will get more penetration, ok but will also cause more damage and this is completely unrealistic.

- If i gave the HE more damage value, will cause more damage, ok but will also penetrate more armor and this is also completely unrealistic.

So can i suggest to add one simple setting?
- In the bomb files we have this "damageAmount" setting. Please also add "armorPenetration" value. This not only is crucial to make AP different in the way they work in comparison to HE but is also needed to make some ships decks immune to smaller bombs as they were IRL.

[Killerfish Games]

Absolutely agree and this is something we've been meaning to add.
Do you have suggested damage and armor penetration values for vanilla bombs?

[Amelia]

I found some old documents concerning the abilities of both USN and IJN bombs, hopefully they help:

USN: https://www.alternatewars.com/WW2/WW2_Documents/Navy_Department/OP1172/OP1172.pdf

IJN: http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/USNTMJ%20Reports/USNTMJ-200E-0465-0531%20Report%200-23.pdf

[the Baron]

Originally posted by Killerfish Games:

Absolutely agree and this is something we've been meaning to add.
Do you have suggested damage and armor penetration values for vanilla bombs?

o7! Thank you.

Sources:
http://pwencycl.kgbudge.com/B/o/Bombs.htm
https://en.wikipedia.org/wiki/List_of_Japanese_World_War_II_navy_bombs
https://bulletpicker.com/pdf/TM%209-1904,%20Ammunition%20Inspection%20Guide.pdf#page=613
https://bulletpicker.com/pdf/OP%201664,%20US%20Explosive%20Ordnance,%20Volume%202.pdf#page=55
https://bulletpicker.com/bomb_-2000-lb-gp_-an-m66.html

"*" this will be my personal notes.

Japanese bombs (only bombs used in antishipping role)

60kg bomb:
Type 99 Number 6 Model 1 Ordinary/ weight 62.8 kg/ Content weight 30kg / Notes: Capable of penetrating 1" (25mm) armor plate. Gave effective fragmentation.

250kg bombs:
- Type 99 No.25 / weight 250 kg / Content weight 60 kg / Notes: Designed in 1938 and adopted in 1939, The usual armament of Navy dive bombers at the start of the war. Capable of penetrating 2" (50mm) armor plate.

- No.25 Model 2 / weight 253kg/ Content weight 103 kg/ Notes: Teardrop shaped. The bomb was used by Japanese forces at the Battle of Midway
*More explosive power in comparison with the Type 99 but less penetration? 35mm?

500kg bomb:
-Type 2 Number 50 Model 1 Ordinary/ weight 491.0 kg/ Content weight 61.4 kg/ Notes:Capable of penetrating 3.1" (80mm) armor plate, making it an armor-piercing bomb by American standards.
*Not used in game by any japanese plane atm but we have the in the game files. Maybe important for a future update.

800kg bombs:
- Type 99 Number 80 Mark 5 Special / weight 796.8 kg / Content weight 22.3 kg/ Notes: Converted from 16" (400mm) armor-piercing shells and used in the attack on Pearl Harbor. Capable of penetrating 6" (150mm) armor plate.

- Type 2 Number 80 Mark 5 Mod 1 Special / weight 811.2kg / Content weight 35.7 kg kg / Notes: Similar to Type 99 Number 80 Mark 5 Special but with a larger explosive charge.
* Both this AP bombs have high penetration but small explosives, to make this interesting would be to always cause a black compartiment where they hit. There is also another 800kg with 400 kg explosives but was designed for skip bombing, and the japanese only start testing skip bombing at 1944, so not relevant in Guadalcanal 1942.

- Type 98? Number 80 / weight 805.0 kg/ Content weight 382kg/ Notes: Mod 1 relaced Shimose with Type 98 explosive. Capable of penetrating 16"(40cm) of reinforced concrete. Used by torpedo bombers acting as horizontal bombers at Midway. Model 1 and Model 2 had different fusing. Mod 1, 2, and 3 of each model had Shimose, Type 91, or Type 98 explosive fill. Capable of penetrating 2.8" (70mm) armor plate. These were the largest bombs in the Japanese Navy inventory.

Jpn bombs summary in game:
60kg: 25mm armor penetration; 30kg explosive.
250kg (AP): 50mm armor penetration; 60kg explosive.
250kg: 35mm armor penetration?; 103kg explosive.
500kg (AP): 80mm armor penetration; 61.4 kg explosive. (*not used in game atm)
800kg (AP): 150mm armor penetration; 35,7 kg.
800kg: 70mm armor penetration; 382kg explosive.

American bombs (only bombs used in antishipping role)

100lb bomb:
- AN-M30/ weight 100 lb (45 kg)/Content weight 54 lb (24 kg)/ Notes: General purpose

250lb bomb:
- AN-M57/ weight 250 lb (113 kg)/Content weight 123 lb (56 kg) Notes: General purpose

500lb bomb:
- AN-M58A1/ weight 500 lb (227 kg)/ Content weight 145 lb (66 kg)/Notes: Used against lightly armored warships.

1000lb bombs:
- M52 (AP)/ weight 1000 lb (454 kg)/ Content weight 50 lb (23 kg)/ Notes: "AP bombs are made to pierce 6 to 7 inches of armor plate". (152mm-177mm) source: https://bulletpicker.com/pdf/TM%209-1904,%20Ammunition%20Inspection%20Guide.pdf#page=613 Converted from naval shells. Obsolescent by 1943.

- AN-Mk33 (AP) / weight 1000 lb (454 kg)/ Content weight 150 lb (68 kg)/ Notes:Introduced October 1942. Capable of penetrating 5" (127mm) deck armor from a 6500' (1980m) in a 300 knot 60 degree dive. Widely used from its introduction date to the end of the war.
*Not used in game but can be important for future campaigns.

- AN-M59 / weight 1000 lb (454 kg)/ Content weight 303 lb (137 kg)/ Notes: Used against lightly armored warships, reinforced concrete.

1600lb bomb:
AN-Mk1 (AP)/ weight 1600 lb (726kg)/ Content weight 209 lb (95 kg)/ Notes:Introduced May 1942. Capable of penetrating 5" (127mm) deck armor from a 4500' (1370m) in a 300 knot 60 degree dive. Too heavy for delivery by naval aircraft other than the TBF Avenger or SB2C Helldiver. Typical carrier loadout rarely exceeded 20 bombs.

2000lb bombs:
- M34 (GP)/ weight 2050 lb (930 kg)/ Content weight 1113 lb (505 kg)/ Notes: M66 was very similar. Too heavy for delivery by naval aircraft other than the TBF Avenger. Typical carrier loadout rarely exceeded 20 bombs. General purpose

- M66 (GP)/ weight 2000 lb (907 kg)/ Content weight 1061 lb (481 kg)/ Notes: "The new-series general purpose
Ibombs (fig. 2-16) are designed for a higher blast effect than general purpose bombs of earlier
design . They are designed for improvedaerodynamic performance and accuracy in flight when released from most altitudes and airspeeds" source: https://bulletpicker.com/pdf/TM%209-1325-200,%20Bombs%20and%20Bomb%20Components.pdf#page=42
*Both are not designed to defeat Yamato deck armor but instead to cause the most damaged possible. General purpose bombs (GP)

American bombs summary in game:
100lb: 20mm armor penetration?; 23kg explosive.
250lb: 30mm armor penetration?; 56kg explosive.
500lb (SAP): 76mm +/- armor penetration; 66kg explosive. (*similar to 250kg japanese bomb)
1000lb (AP): 152mm-177mm armor penetration; 23kg explosive.
1000lb (SAP): 95mm +/- armor penetration; 137kg explosive.
1600lb (AP): 152mm +/- armor penetration; 95kg explosive.
2000lb: 80mm armor penetration?; 481Kg (*i choose the M66 variant since it have the AN designation "Army-Navy bombs"

Other notes:
The Baltimore in my research i got the info that the deck armor above the citadel (65mm) was enough to withstand 250kg bombs. The Yamato armor deck above the citadel (230mm-200mm) was designed to withstand 1000lb bombs.

Maybe General Douglas can find more information about the american bombs penetration.

About damage: (running tests)
- "The Americans estimated that three hits with 500 lb (227 kg) GP bombs would almost certainly sink a 1630-ton destroyer and had a 70% chance of sinking a 2100-ton destroyer."
*Works fine against light destroyers, however it have the same impact against heavy destroyers. 3 hits in different places is deadly most of the times. "damageAmount":620.0 AN-M58A1/ weight 500 lb (227 kg)/ Content weight 145 lb (66 kg)

- "Three hits with 1000 lb (454 kg) GP bombs had a 95% chance of sinking a relatively lightly protected Atlanta-class light cruiser and a 30% chance of sinking a 10,000-ton heavy cruiser."
*In game seems to work right against the Atlanta, the problem is against heavy cruisers where it seems to get similar results, however this can be minimize in game with the bomb armor penetration against some heavy cruisers. "damageAmount":1250.0 for the AN-M59 / weight 1000 lb (454 kg)/ Content weight 303 lb (137 kg)

- "Six hits with the 1000-lb bomb gave a 80% chance of sinking a heavy cruiser."

- "The Americans estimated that seven penetrating bomb hits would be enough to sink a battleship, while the Japanese estimated that 12 to 16 penetrating hits were required. American operational analysts later revised their estimates, concluding that the Mark 33 could sink a battleship only if it hit a magazine, which worked out to a 79% chance of sinking a battleship with six penetrating hits."

Conclusion:
In my tests it seems a factor by x10 seems to be good balance. If i take the:
- AN-M30/ weight 100 lb (45 kg)/Content weight 54 lb (24 kg)
- M52 (AP)/ weight 1000 lb (454 kg)/ Content weight 50 lb (23 kg)
And i gave them a x8 multiply value so "damageAmount":184.0 it seems they would cause only light damage where when is above 200 already starts to do some relevant damage.
The problem with CAs being too vulnerable against 1000lbs can be minimized by the bomb armor pemetration against some heavy cruisers deck armor or maybe by adding a new cells column to the heavy cruisers.

Jpn bombs summary in game:
60kg: 25mm armor penetration; 30kg explosive. "damageAmount":300.0
250kg (AP): 50mm armor penetration; 60kg explosive. "damageAmount":600.0
250kg: 35mm armor penetration?; 103kg explosive. "damageAmount":1030.0
500kg (AP): 80mm armor penetration; 61.4 kg explosive. "damageAmount":614.0
800kg (AP): 150mm armor penetration; 35,7 kg. "damageAmount":357.0
800kg: 70mm armor penetration; 382kg explosive. "damageAmount":3820.0

American bombs summary in game:
100lb: 20mm armor penetration?; 23kg explosive. "damageAmount":230.0
250lb: 30mm armor penetration?; 56kg explosive. "damageAmount":560.0
500lb (SAP): 76mm +/- armor penetration; 66kg explosive. "damageAmount":660.0
1000lb (AP): 152mm-177mm armor penetration; 23kg explosive."damageAmount":230.0
1000lb (SAP): 95mm +/- armor penetration; 137kg explosive. "damageAmount":1370.0
1600lb (AP): 152mm +/- armor penetration; 95kg explosive. "damageAmount":950.0
2000lb: 80mm armor penetration?; 481Kg "damageAmount":4810.0

[Herr Flick]

Excellent as always baron I’m looking forward to these correct penetration bombs I’ve often wondered what’s the difference with AP and HE as nothing was listed 👍🏻. The American bombs went for more packed explosives rather than penetration, fillings were 30-40% of the bombs weight was explosives so looking it had a much weaker bomb case as the inside was filled with a lot more HE material. Can you add the 500lb to the B17 by any chance? Looking they used them in 1942 way more than the monster bombs in game eg when trying to take out the Hiei they hit her with at least 1 500lb bomb no mentions of 1000 or 2000, I think it would carry 8?

[the Baron]

Originally posted by HD-18thGA.C Cpl. Zippo:

Excellent as always baron I’m looking forward to these correct penetration bombs I’ve often wondered what’s the difference with AP and HE as nothing was listed 👍🏻. Can you add the 500lb to the B17 by any chance? Looking they used them in 1942 way more than the monster bombs in game eg when trying to take out the Hiei they hit her with at least 1 500lb bomb no mentions of 1000 or 2000, I think it would carry 10?

It seems it could carry 16 at short distances and 8 at long distances but i am not 100% sure.

[Markus1987]

Originally posted by the Baron:

Originally posted by HD-18thGA.C Cpl. Zippo:

Excellent as always baron I’m looking forward to these correct penetration bombs I’ve often wondered what’s the difference with AP and HE as nothing was listed 👍🏻. Can you add the 500lb to the B17 by any chance? Looking they used them in 1942 way more than the monster bombs in game eg when trying to take out the Hiei they hit her with at least 1 500lb bomb no mentions of 1000 or 2000, I think it would carry 10?

It seems it could carry 16 at short distances and 8 at long distances but i am not 100% sure.

Very good, Baron, I would love to see an update on this through this information. Would be great if the B 17 could carry more bombs

[the Baron]

Originally posted by Markus1987:

Originally posted by the Baron:

It seems it could carry 16 at short distances and 8 at long distances but i am not 100% sure.

Very good, Baron, I would love to see an update on this through this information. Would be great if the B 17 could carry more bombs

Already done. In the next update the B17 will have the option (default payload) to carry 8x 500lb bombs.
I tried to add the 16x option but the game engine don't let me use more than 8 bombs it seems.

[Markus1987]

Originally posted by the Baron:

Originally posted by Markus1987:

Very good, Baron, I would love to see an update on this through this information. Would be great if the B 17 could carry more bombs

Already done. In the next update the B17 will have the option (default payload) to carry 8x 500lb bombs.
I tried to add the 16x option but the game engine don't let me use more than 8 bombs it seems.

Maybe KFG can do something about it

[the Baron]

Originally posted by Markus1987:

Originally posted by the Baron:

Already done. In the next update the B17 will have the option (default payload) to carry 8x 500lb bombs.
I tried to add the 16x option but the game engine don't let me use more than 8 bombs it seems.

Maybe KFG can do something about it

If possible great but is not important. The 16x variant don't have the range to reach from New Hebrides to Guadalcanal. However can be interesting the moment the americans have an airfiled level 3 in the area.

[Markus1987]

Originally posted by the Baron:

Originally posted by Markus1987:

Maybe KFG can do something about it

If possible great but is not important. The 16x variant don't have the range to reach from New Hebrides to Guadalcanal. However can be interesting the moment the americans have an airfiled level 3 in the area.

That would be quite enough with only x 8 as payload
The Betty fits I think so, or would that also need a larger payload?

[Herr Flick]

This is great!

Originally posted by the Baron:

Originally posted by Markus1987:

Very good, Baron, I would love to see an update on this through this information. Would be great if the B 17 could carry more bombs

Already done. In the next update the B17 will have the option (default payload) to carry 8x 500lb bombs.
I tried to add the 16x option but the game engine don't let me use more than 8 bombs it seems.

[Killerfish Games]

Thanks for the detailed data!
We'll look into getting this in-game.

[Instigator]

Best dev ever!

[Amelia]

It's hard to find penetration values for US bombs but I am still searching

[the Baron]

Originally posted by Killerfish Games:

Thanks for the detailed data!
We'll look into getting this in-game.

Thank you!

Originally posted by General_Douglas:

It's hard to find penetration values for US bombs but I am still searching

I found something interesting.

https://www.alternatewars.com/WW2/WW2_Documents/Navy_Department/OP1172/OP1172.pdf

Table 5 penetration of reinforced concrete in horizontal bombing
Table 6 Penetration of reinforced concrete in dive bombing

500 lb. S.A.P., AN-i\158
1000 lb. S.A.P., AN-M59 30% more +/-
1000 lb. A.P., AN-Mk.33 65% more+/-
1600 lb. A.P. AN-Mk.l 100% more +/-

*average values in comparison with the 500 lb. S.A.P., AN-i\158 performance. Different heights give different results.

And we know the 1000 lb. A.P., AN-Mk.33 was designed to pierce 127mm deck armor.

So the values would +/- something like this.

500 lb. S.A.P., AN-i\158 76mm +/-
1000 lb. S.A.P., AN-M59 95mm +/-
1000 lb. A.P., AN-Mk.33 127mm
1600 lb. A.P. AN-Mk.l 152mm +/-

Note:
-AN-Mk1 (AP)/ weight 1600 lb (726kg)/ Content weight 209 lb (95 kg)/ Notes:Introduced May 1942. Capable of penetrating 5" (127mm) deck armor from a 4500' (1370m)

- AN-Mk33 (AP) / weight 1000 lb (454 kg)/ Content weight 150 lb (68 kg)/ Notes:Introduced October 1942. Capable of penetrating 5" (127mm) deck armor from a 6500' (1980m) in a 300 knot 60 degree dive.

*Important: Note both bombs having the same penetration, however they are dropped from different heights so looking at the tables is clear that AN-Mk1 (AP-1600lb) have higher penetration.