Ground bombing is borked, part II

[herwin]

ORIGINAL: mdiehl

The lethal radius of a 500 pound bomb was 60-90 feet

I'd like to see a link to support that with some more details. 90 feet was probably the "100%" lethal radius. Meaning that every person prone, sitting, or standing within 90 of a 500lb bomb who didn't have a concrete wall between themself and the blast was either blown to bits or killed by the concussion. The "really good chance you could be killed by the detonation" radius was probably on the order of 150 feet. And the "induces shock, ruptured eardrums, broken limbs, and a general unwillingness to be combat effective" radius may have been much greater still.

The lethal radius is an approximation, since the blast and fragmentation patterns are not really circular. (This is most apparent with field guns, where the pattern is approximately ellipsoidal or even crescent moon in shape.) It's the average distance from the point of impact corresponding to a 0.5 probability of producing a casualty--take the lethal area and treat it as the area of a circle, then calculate the radius. Blast radius is reportedly 40 feet, nominal lethal radius is 60 feet, troops in the open, standing and not taking cover are vulnerable at 90 feet. My sources were unclassified, but nowadays, Google is your friend.

[mdiehl]

One of the things you can google is a USAAF WW2 pilots ordnance document that lists the minimum safe bombing altitude for the US 500 lb GP bomb as 2500 feet. Even allowing for a good margin of safety built into that distance, I think it suggests that a 500 lb bomb detonating anywhere near a man in the open where "near" is on the order of 100-200 yards would be a BAD THING for the person so exposed. If the bomb is a threat to the bomber 1000 feet or even 500 feet away, you can bet its a greater threat to a person on the ground with no cover or other protection against the detonation.

[herwin]

ORIGINAL: US87891

ORIGINAL: mdiehl

The lethal radius of a 500 pound bomb was 60-90 feet

I'd like to see a link to support that with some more details. 90 feet was probably the "100%" lethal radius. Meaning that every person prone, sitting, or standing within 90 of a 500lb bomb who didn't have a concrete wall between themself and the blast was either blown to bits or killed by the concussion. The "really good chance you could be killed by the detonation" radius was probably on the order of 150 feet. And the "induces shock, ruptured eardrums, broken limbs, and a general unwillingness to be combat effective" radius may have been much greater still.

There are no such links, except on the internet which express a very simplistic appreciation of a weapon's effectiveness. That simplistic effect is what the poster may have been referring to.

A bomb or shell's lethal radius is the function of many factors, not the least of which is the fuze timing. Bury the bomb or shell, before fuze activation, and its lethal radius goes to hell. Bombs and shells have two primary kill modes, kinetic kills by fragmentation and bio-rupture kills by blast over-pressure. The primary kill mechanism is fragmentation. Blast over-pressure is a secondary kill mechanism. The lethal radius of a 500 pound GP bomb, contact fuzed, against exposed soft targets, for a 10% hit probability, was approximately 100 yards.

The utility of large bombs, and shells, was their ability to stun and disrupt areal targets.

Matt

The way I heard it described was that troops under artillery fire tended to take cover and were easy to find and reorganise afterwards. Troops being attacked by air attack scattered away from the apparent aim point and took much longer to round up afterwards. Now, I've never been under fire, so I'm just reporting what colleagues told me when I was working on command and control systems for ground combat operations. (Inter alia, I was the chief systems engineer for TCO during 1982-89, and I had to learn something during that period. [:'(] )

--actually I was once under fire, but I was eleven at the time. My father had the family take cover, got his Johnson M1941 semiautomatic, and moved to the flank of the target shooters who weren't thinking about the possibility that farmers were living in the country behind the targets they had set up to try out their new weapons. Nobody was hurt.--

[herwin]

ORIGINAL: Bullwinkle58

ORIGINAL: witpqs

It's the 'defending in open terrain' part at that point in the campaign that I have the most trouble with. If your forces are defending they are most certainly located.

And bombers with no AA, no fighters, in good weather at 6000 feet couldn't possibly have pathfinders, or fighters, leading the way to the troop concentrations. Nope, those USAAF guys were complete idiots.

Well, we didn't have much good to say about those goddamn airforce targeteers. On the other hand, Marine aviators were always good to have on your side.

[herwin]

ORIGINAL: mdiehl

One of the things you can google is a USAAF WW2 pilots ordnance document that lists the minimum safe bombing altitude for the US 500 lb GP bomb as 2500 feet. Even allowing for a good margin of safety built into that distance, I think it suggests that a 500 lb bomb detonating anywhere near a man in the open where "near" is on the order of 100-200 yards would be a BAD THING for the person so exposed. If the bomb is a threat to the bomber 1000 feet or even 500 feet away, you can bet its a greater threat to a person on the ground with no cover or other protection against the detonation.

That what you needed to minimise the chance of a friendly fire incident. Some fragments could carry significant energy a long way. [;)]

[USSAmerica]

ORIGINAL: Bullwinkle58

ORIGINAL: herwin


I accept that, but we're dealing with divisions spread over at least 15 miles of road space on a march or at least 25 square miles deployed. The lethal radius of a 500 pound bomb was 60-90 feet, so it took a minimum of 1500 bombs for 70% casualties on a marching division assuming it stayed visible in 4s on a road--and the normal effect of air attack was for the unit to scatter away from the aim points--or 250,000 bombs for 70% casualties on a deployed division.

You're making stuff up now, professor.

We're dealing with a hex. Just that, a hex. You should know after all the posts to you by the devs that this is not a simulation with a military-grade tactical engine. IT'S A HEX. It's a data point. There are no statistical distributions of men inside that data point, no "2399 men in the first 0.8 mile, then a gap of .072 miles where that platoon stopped to take a piss, then a gaggle at .56 miles where the company clown was telling a really good story and they drew in to hear." It's a hex.

In exchange for it being just a hex, all the AA has instantaneous azimuth and range on any and all aircraft in the hex. Every manjack in the LCU has the same fortification level (no lazybones with the digging), the same health, the same psychological state, the same training. Nobody panics and runs away. Nobody goes crazy. No officers get fragged for dragging those poor draftees onto that godforsaken plain to get their behinds bombed by uber-bombers from Wichita, Kansas. Why? Because it's a hex.

Similarly, your manuals about how "every" division deploys are just that. Manuals. Are they Japanese manuals for operations versus the Soviets in Asia? And exactly 25 square miles. Really? What if it's only 22 square miles? Does somebody get demerits? Well, no. It's just a hex.

It's altitude, speed, terrain, op mode, pilot stats, aircraft stats, weapon stats, weather, and some randoms. You can quote manuals to the end of time and the model is going to be that. Why? Because it's a hex.

[rader]

I would say this might be an example of how ground bombing is borked the other way.

Tu-2 is a specific ground attack bomber. Yet over a hundred of them merely manage to destroy a few squads...

How come 4E bombers do way more damage than planes actually designed for the ground attack role?






And before you point this out, yes it's rough terrain, but do you seriously think 46 times the damage is a reasonable result for B-29s compared with Tu-2s? (26 times the damage per plane...)

[rader]

Even worse, IL-2s. These are specific (and very effective) ground attack aircraft... yet they do basically nothing. And yet 4E bombers are wonder weapons at ground attack [8|]

[witpqs]

I'll wager you already know the answer. The bombs are what they are, and the game engine does not distinguish them by what platform delivered them.

[rader]

ORIGINAL: witpqs

I'll wager you already know the answer. The bombs are what they are, and the game engine does not distinguish them by what platform delivered them.

Yes, I know the answer - I'm just pointing out that it might need re-examination [:D]

[Bullwinkle58]

ORIGINAL: witpqs

I'll wager you already know the answer. The bombs are what they are, and the game engine does not distinguish them by what platform delivered them.

Except, among other variables which may or may not be in the model, this plane has a max bomb-load of 8300 lbs, and a B-29 carries 20,000. Better bomb sight? I'm sure the B-29s aiming was a bit better.

This is also 10,000 feet, not 6000. We can't see AA and CAP sections. But a number were damaged, By what?

Bomb-load, terrain, altitude, accuracy, opposition. And there are different results!

[rader]

Better results, ok but 26 times better results? [8|]

Attack mode should make more of a difference than bomb load for ground attack (unlike city attack).

Why do you think they invented dive bombing and fighter-bombers? Because level bombers are crap at hitting anything smaller than a city block.

[Bullwinkle58]

ORIGINAL: rader

Better results, ok but 26 times better results? [8|]

Attack mode should make more of a difference than bomb load for ground attack (unlike city attack).

Why do you think they invented dive bombing and fighter-bombers? Because level bombers are crap at hitting anything smaller than a city block.

Except 200 B-29s at 6000 feet hit 200 icity blocks with 20,000 LBS per plane. When you compare this to dive bombing it's nuts. Not that 200 DBs could bomb in tight quarters without committing widespread fratricide . . .

Jsut for grins I ran the below attack in my current May 1945 game. It's not exactly congruent to yours. I only had one sighted Japanese unit not in a base hex in range of my B-29 base on Sakhalin Island, and it was a fortress. It was not in Move mode, and was, obviously, fortified. Terrain is wooded. It was also not reconned in any way. I bombed at 6000 feet, no fighter escort. Only B-29s, several models. I didn't play with COs. They were rested, but not every unit is filled out. The weather was rainy.

Japanese losses were 10 squads KIA, and 2 guns.

I think forts, terrain, and op mode are EXTREMELY relevant to the results you report seeing in your game.
--------------------------------------------------------------------------------------------------------------------------------

Morning Air attack on 3rd Border Defense Fortress, at 112,42 , near Mutankiang

Weather in hex: Heavy rain

Raid spotted at 30 NM, estimated altitude 10,000 feet.
Estimated time to target is 9 minutes


Allied aircraft
B-29-1 Superfort x 3
B-29-25 Superfort x 71
B-29B Superfort x 164

No Allied losses

Japanese ground losses:
993 casualties reported
Squads: 5 destroyed, 47 disabled
Non Combat: 2 destroyed, 63 disabled
Engineers: 3 destroyed, 14 disabled
Guns lost 15 (2 destroyed, 13 disabled)


Aircraft Attacking:
9 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
12 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
12 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
15 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
3 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
12 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
9 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
3 x B-29B Superfort bombing from 6000 feet
Ground Attack: 36 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
3 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
3 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 36 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 36 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
3 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
3 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 36 x 500 lb GP Bomb
3 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
2 x B-29-25 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
3 x B-29-1 Superfort bombing from 6000 feet
Ground Attack: 20 x 500 lb GP Bomb
14 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb
3 x B-29B Superfort bombing from 6000 feet
Ground Attack: 45 x 500 lb GP Bomb

[sandman455]

ORIGINAL: US87891

There are no such links, except on the internet which express a very simplistic appreciation of a weapon's effectiveness. That simplistic effect is what the poster may have been referring to.

A bomb or shell's lethal radius is the function of many factors, not the least of which is the fuze timing. Bury the bomb or shell, before fuze activation, and its lethal radius goes to hell. Bombs and shells have two primary kill modes, kinetic kills by fragmentation and bio-rupture kills by blast over-pressure. The primary kill mechanism is fragmentation. Blast over-pressure is a secondary kill mechanism. The lethal radius of a 500 pound GP bomb, contact fuzed, against exposed soft targets, for a 10% hit probability, was approximately 100 yards.

The utility of large bombs, and shells, was their ability to stun and disrupt areal targets.

Matt

Ah yes, someone who knows.

/salute


I've have avoided this thread until now. And given the conviction of many, I doubt anything I would say would be of much use anyway. Besides, it has been almost 2 decades since I made a living doing such stuff. And even today I'm scared that I might cross the boundries of what is history, what is common sense, and what is not suppose to be discussed, ever.


All I will say is that the man from Canada has some valid points.


The only advice I'd give to my fellow players is let history be your guide. The brains of their day, knew the limitations of the platforms/weapons and this applies to both sides. I feel comfortable in saying that if they thought it would work, then they would have done it. If they didn't do it, or you didn't read about them doing it, then there are probably some very good reasons why they didn't.


When do you guys find time to play anyway?

[LoBaron]

Ok, as witpqs and The Moose already pointed out, the whole thing is pretty simple.

We have a couple of variables which influence how much damage a raid deals to the target per plane.
DL, MDL, AA, weather, crew skill, bomb size, number of bombs, distance to target, morale, terrain, number of units in hex, type of devices in hex, bombing altitude.

There is no separate formula per delivery platform (which puts all level bombers on equal footing except for bomb load and size, and
this is the reason for HB always soming out on top of LB...). There is only a certain difference between dive and level bomb
which seems to be outweighted by number of bombs dropped.

So: if all or most variables hand a + to the attacker and he incidentially flies an HB at 6k the game engine favoures extreme results.
And: if you nerf HB effectiveness chances are you will nerf low-med skil bombing, high alt bombing, and MB and LB effectiveness.
Also: the drawbacks of operating HB instead of MB/LB are pretty much AF size/supply consumption/service level and are outweighted by the advantages.

So nothing new here. Now, when the question comes to how to solve this, you get 100 different proposals
ranging from impossible to ineffective, or from-doesn´t-change-a-thing to nerfs-the-other-end-of-the-spectrum.

Which means the solution is complex that it probably will not be possible to implement with our dedicated one-man-show or needs to be weighted
extremely carefully and my show up in +1 year in the modders section.


You don´t need a 7 pager to come to this conclusion, this was already pretty obvious before this thread existed, and a simple HR takes care of things
better than any state of the art patch can. Which was also pretty obvious from the start. [:)]

[herwin]

ORIGINAL: rader

I would say this might be an example of how ground bombing is borked the other way.

Tu-2 is a specific ground attack bomber. Yet over a hundred of them merely manage to destroy a few squads...

How come 4E bombers do way more damage than planes actually designed for the ground attack role?






And before you point this out, yes it's rough terrain, but do you seriously think 46 times the damage is a reasonable result for B-29s compared with Tu-2s? (26 times the damage per plane...)

That kind of damage (1 casualty per bomber) is my rule of thumb.

[herwin]

ORIGINAL: US87891

ORIGINAL: mdiehl

The lethal radius of a 500 pound bomb was 60-90 feet

I'd like to see a link to support that with some more details. 90 feet was probably the "100%" lethal radius. Meaning that every person prone, sitting, or standing within 90 of a 500lb bomb who didn't have a concrete wall between themself and the blast was either blown to bits or killed by the concussion. The "really good chance you could be killed by the detonation" radius was probably on the order of 150 feet. And the "induces shock, ruptured eardrums, broken limbs, and a general unwillingness to be combat effective" radius may have been much greater still.

There are no such links, except on the internet which express a very simplistic appreciation of a weapon's effectiveness. That simplistic effect is what the poster may have been referring to.

A bomb or shell's lethal radius is the function of many factors, not the least of which is the fuze timing. Bury the bomb or shell, before fuze activation, and its lethal radius goes to hell. Bombs and shells have two primary kill modes, kinetic kills by fragmentation and bio-rupture kills by blast over-pressure. The primary kill mechanism is fragmentation. Blast over-pressure is a secondary kill mechanism. The lethal radius of a 500 pound GP bomb, contact fuzed, against exposed soft targets, for a 10% hit probability, was approximately 100 yards.

The utility of large bombs, and shells, was their ability to stun and disrupt areal targets.

Matt

Just curious, because 10% hit probability comes up. Is that the distance to the 10% lethality contour? Or is that (slightly different) a 10% probability of a fragment impacting on an exposed soft target with enough energy to cause a casualty?

[PaxMondo]

ORIGINAL: Bullwinkle58

Japanese losses were 10 squads KIA, and 2 guns.

I think forts, terrain, and op mode are EXTREMELY relevant to the results you report seeing in your game.
--------------------------------------------------------------------------------------------------------------------------------

Morning Air attack on 3rd Border Defense Fortress, at 112,42 , near Mutankiang

Weather in hex: Heavy rain

Raid spotted at 30 NM, estimated altitude 10,000 feet.
Estimated time to target is 9 minutes


Allied aircraft
B-29-1 Superfort x 3
B-29-25 Superfort x 71
B-29B Superfort x 164

No Allied losses

Japanese ground losses:
993 casualties reported
Squads: 5 destroyed, 47 disabled
Non Combat: 2 destroyed, 63 disabled
Engineers: 3 destroyed, 14 disabled
Guns lost 15 (2 destroyed, 13 disabled)

I think what most players are seeing is: Now bomb the next turn. The disrupted units will not have fully recovered, and will be destroyed. 3 turns, you will have nothing left.

But, as has already been pointed out, this isn't going to get changed in spite of the game consequences. LoBaron is correct, for PBEM HR's can be erected to mitigate. For AI players, you have to break out the editor. I would suggest moving on. There a lovely picture of BB that is far more appealing in another thread .... [:D]

[Bullwinkle58]

ORIGINAL: PaxMondo

I think what most players are seeing is: Now bomb the next turn. The disrupted units will not have fully recovered, and will be destroyed. 3 turns, you will have nothing left.

If I were really bored today I'd run two more turns and see. But I'm not that bored.

But, as has already been pointed out, this isn't going to get changed in spite of the game consequences. LoBaron is correct, for PBEM HR's can be erected to mitigate. For AI players, you have to break out the editor.

As a moose with some repute as an AI-only player I have to say that this test was the first time I've ever even considered using hundreds of B-29s to bomb an LCU in the open. Never even occurred to me. I use them historically, for City strikes 90%, and about 10% for Port strikes in the HI where I suspect or know there are fuel-starved ships squatting at the pier.

I have used lesser LBs to Ground attack in Burma, Java, Sumatra, and Indo-China, often to try to finish off routed units in the bush. Results have been unsatisfactory. One unit in northern Burma I've been strafing at 100 ft. with P-47s daily for over six months. At this point it's more a point of comedy than anything else for me.

The AI abhors leaving LCUs in the open pretty much everywhere except China. Most ground attacks necessarily are on some level of urban terrain and don't score division-killing numbers. For PBEM players I'd say again: just say no to HRs. Put your men in cities, not the fields.

[Erkki]

There often is no option but to use a clear terrain hex. You have to move through them or occupy them to avoid getting flanked. Maybe AI doesn't know how to flank but always attacks directly, but real people do...