Ground bombing is borked, part II

[rader]

ORIGINAL: Bullwinkle58

Yeah, A BUFF can carry more bombs that a B-29. But that was one B-52 in those vidoes. Why would you think a division in the open with no forts would survive a week?

Because there's probably almost no such thing as "clear terrain" at the strategic level. We aren't talking about open steppe - were talking about towns, fields, streams, etc. spread out over a large distance. It's unlikely that level bombers would consistently even hit the right area - most level bombing was off by hundreds of yards. And if in formation, how the heck would they cover more than a square mile?

[herwin]

ORIGINAL: Bullwinkle58

ORIGINAL: rader

Forts help, but don't allow you to hold clear terrain without a LOT of AA. I had level 6 forts in Hailar, and 3-4 units including a big fortress were trashed in a matter of days by B-29s. You could have destroyed all the units in Hailar (about a division equivalent) in about a week. It's really clear terrain that's borked (and the fact that 4E bombers are so much better at bombing ground units than ground attack planes are).

500 lb iron bombs being dropped on clear terrain:

http://www.youtube.com/watch?v=sks6D2l8erA

http://www.youtube.com/watch?v=dGLgZ8ht ... re=related

Yeah, A BUFF can carry more bombs that a B-29. But that was one B-52 in those vidoes. Why would you think a division in the open with no forts would survive a week?

Hi, Bullwinkle58. Just wondering, but wasn't there a major sea change in weapons guidance between 1975 and 1995? Through the Viet-Nam War, bomb CEP was about 1000 feet at best. The performance of the 8th AF at St. Lo was typical through 1975--5000 or so bombs on the front occupied by the Panzer Lehr produced about 30% casualties. Not many people remember the old days.

[obvert]

The largest number of defender casualties I would expect to see in a day for a corps versus division battle is about 400.

I have calibration data for the Burma campaign, and they are consistent with the OCS combat model. They are not consistent with the WitP-AE ground combat model.

There's been some interest in calibrating air attacks on troops. In OCS, a Sally or a Beaufighter unit (somewhere in the range of 20-45 aircraft) in Burma has an expectation of causing about 10 casualties per day. A fighter-bomber unit (same size range) can be expected to cause about 3 casualties a day. A Vengence unit, perhaps 15 per day. A B-25 was good for about 20/day, and a B-24 about 3 casualties a day (high-level bombing). The game engine produces about ten times that number.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

Wouldn't it be amazing if the units mentions above performed in the proportion stated? And the same for their Japanese equivalents? How could this be done?

I would be happy if a B-25 was stronger than a B-24 for ground attacks, and a Nick stronger than a Sally.

[LoBaron]

I show you whats borked:

[Bullwinkle58]

ORIGINAL: rader

ORIGINAL: Bullwinkle58

Yeah, A BUFF can carry more bombs that a B-29. But that was one B-52 in those vidoes. Why would you think a division in the open with no forts would survive a week?

Because there's probably almost no such thing as "clear terrain" at the strategic level. We aren't talking about open steppe - were talking about towns, fields, streams, etc. spread out over a large distance. It's unlikely that level bombers would consistently even hit the right area - most level bombing was off by hundreds of yards. And if in formation, how the heck would they cover more than a square mile?

See, now you're waffling. "Clear" terrain doesn't mean billiard tables. It means not triple canopy rain forest, the Black Forest, dense urban, or mountains. One of those videos is of hilly terrain. But if you want to see what 500LB bombs did in triple canopy, search "Arc Light" in YouTube. What you have afterward is . . . a billiard table.

Your opponent posted the conditions you're citing against, and they don't help your story. No AA, no fighters, 6000 feet, move mode unfortified troops, decent weather. With no flak at 6000 feet any bombardier who couldn't hit large troop formations would be shown the door. Arc Light B-52s flew in formations of three, in arrowhead, and each stick covered a linear mile of impact. They flew at very high altitudes, with more advanced bombing instruments than were available in WWII. (Remember, however, Arc Light was only 20 years after the period in your game under discussion.) So, do the reverse math for B-29s with smaller bomb loads, but at 6000 feet, and with 60 planes instead of three. Boomski.

You complain that ground bombing prevents you from defending, in 1945, large pieces of real estate because you as the Japanese don't have AA or air superiority. Well, WAAAAH. That was the whole point. The US didn't design and build the second most expensive weapon system of WWII, the B-29, so the Japanese could have a fair fight.

I posted those video links so folks who think a stick of 500Lb bombs looks like a mortar going off can reconsider. If you watched them my work here is done. If you can't sit in open territory in the late game without getting killed, move elsewhere, or dig in. War is hell.

[Bullwinkle58]

ORIGINAL: herwin

Hi, Bullwinkle58. Just wondering, but wasn't there a major sea change in weapons guidance between 1975 and 1995? Through the Viet-Nam War, bomb CEP was about 1000 feet at best. The performance of the 8th AF at St. Lo was typical through 1975--5000 or so bombs on the front occupied by the Panzer Lehr produced about 30% casualties. Not many people remember the old days.

The videos are from circa 1967. The bomb silhouette was changed to be more aerodynamic versus 1945, but they were essentially the same beast. Perhaps the detonating compounds were improved--I'd expect so--but someone more into ordnance than me would need to confirm that.

Bomb CEP is a function of lots of things, altitude being a primary issue. Arc Light drops were VERY high, beyond aural detection range. In rader's game his opponent is droping at 6000 feet. Not the same thing.

St. Lo is not the same terrain at issue here, and we aren't talking about bombing armor, but men in unfortified positions. Again, apples, oranges. Also, 30% additive over succeeding days is not 30%.

There IS NO RL data for the type of strikes rader's opponent is carrying out. It's speculation and the model doing its best.

[witpqs]

I want the bombing model to be as good as possible, and I do understand that adjustments to parts of it might be in order, but when I read Rader's comments about not being able to defend in open terrain at that point in the game I had similar thoughts. Especially after seeing JZanes synopsis of the conditions, which are quite different than I understood from Rader.

[witpqs]

ORIGINAL: Bullwinkle58

ORIGINAL: herwin

Hi, Bullwinkle58. Just wondering, but wasn't there a major sea change in weapons guidance between 1975 and 1995? Through the Viet-Nam War, bomb CEP was about 1000 feet at best. The performance of the 8th AF at St. Lo was typical through 1975--5000 or so bombs on the front occupied by the Panzer Lehr produced about 30% casualties. Not many people remember the old days.

The videos are from circa 1967. The bomb silhouette was changed to be more aerodynamic versus 1945, but they were essentially the same beast. Perhaps the detonating compounds were improved--I'd expect so--but someone more into ordnance than me would need to confirm that.

Bomb CEP is a function of lots of things, altitude being a primary issue. Arc Light drops were VERY high, beyond aural detection range. In rader's game his opponent is droping at 6000 feet. Not the same thing.

St. Lo is not the same terrain at issue here, and we aren't talking about bombing armor, but men in unfortified positions. Again, apples, oranges. Also, 30% additive over succeeding days is not 30%.

There IS NO RL data for the type of strikes rader's opponent is carrying out. It's speculation and the model doing its best.

I don't know about the bombs in the video, but it's my understanding that MANY of the bombs used in Vietnam were WWII manufacture.

[Bullwinkle58]

ORIGINAL: witpqs

I don't know about the bombs in the video, but it's my understanding that MANY of the bombs used in Vietnam were WWII manufacture.

I found other videos of Operation Linebacker in 1972 with B-52s being loaded with WW2-era-design fat-boy 500-LBers. I'm not an ordie, but I think the slimmer design in the 1967 videos was brand new then. Those are the models which took the Snake Eye add-on package for reduced drag, low-altitude release from tactical FBs.

Edit: I ran across more data which says that the WWII-era bombs were used late in Vietnam due to better explosive-to-casing ratios for the targets of those strikes. The Mk 80 line, of which the most common 500 LB variant was and is the Mk 82, was developed in the late-1950s for better aerodynamics in external pylon use. But the old fat-boys were retained for internal use when best for the mission.

[herwin]

ORIGINAL: Bullwinkle58

ORIGINAL: herwin

Hi, Bullwinkle58. Just wondering, but wasn't there a major sea change in weapons guidance between 1975 and 1995? Through the Viet-Nam War, bomb CEP was about 1000 feet at best. The performance of the 8th AF at St. Lo was typical through 1975--5000 or so bombs on the front occupied by the Panzer Lehr produced about 30% casualties. Not many people remember the old days.

The videos are from circa 1967. The bomb silhouette was changed to be more aerodynamic versus 1945, but they were essentially the same beast. Perhaps the detonating compounds were improved--I'd expect so--but someone more into ordnance than me would need to confirm that.

Bomb CEP is a function of lots of things, altitude being a primary issue. Arc Light drops were VERY high, beyond aural detection range. In rader's game his opponent is droping at 6000 feet. Not the same thing.

St. Lo is not the same terrain at issue here, and we aren't talking about bombing armor, but men in unfortified positions. Again, apples, oranges. Also, 30% additive over succeeding days is not 30%.

There IS NO RL data for the type of strikes rader's opponent is carrying out. It's speculation and the model doing its best.

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.

[rader]

I accept the fact that if the Japanese units all clustered together in a pre-arranged open field, level bombers might be able to systematically eliminate them.

And I would expect "relatively high" losses due to air attack under the game conditions (but probably more from straffing fighter bombers than level bombers). But I don't see how anyone can consider half a of division eliminated per day can be considered in any way reasonable.

How would they actually find all the troops to kill them and bomb them so accurately? Try locating infantry men moving through farmland at even 6Kft. Try determining which are japanese and which are manuchurian civilians or refugees (not that they wouldn't be considered acceptable "collateral damage"). But how would level bombers in formation at altitude accurately target and entirely eliminate units spread out over a wide area? This makes no snese whatsoever for pattern bombing.

[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.

[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.

[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.

[Bullwinkle58]

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.

Sixty feet is six car lenghts. I invite Herwin to stand seven car lengths from a exploding 500 lb ground burst. You know, if he feels lucky.

[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

[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.

[Cribtop]

Bullwinkle, I agree with your premise from a few posts back, namely in clear terrain the defender needs to move or dig in. I think one of the questions presented, particularly in PzB's example, is whether digging in, a/k/a fort levels, is sufficiently modeled to reduce bombing effects.

[Bullwinkle58]

ORIGINAL: Cribtop

Bullwinkle, I agree with your premise from a few posts back, namely in clear terrain the defender needs to move or dig in. I think one of the questions presented, particularly in PzB's example, is whether digging in, a/k/a fort levels, is sufficiently modeled to reduce bombing effects.

Field forts, the number on the top left of the LCU screen, have always been assumed, and I believe sorta kinda dev confirmed, to be basic, crude structures. Slit trenches, log bunkers, maybe some sandbags. Combat engineer stuff. Nothing permanent, certainly no concrete. Some of these structures help against shrapnel. A lot less against overpressure and heat/flame. When I bomb ground formations, and there's flak, or fighters, or both I don't wipe out half divisions. I'm using B-29s to bomb in Java and Sumatra now, and they face both sorts of defenses. I get numbers more on the order of 15 diasabled and 2 KIA squads for 30 B-29s from 10,000 feet. Yes there are terrain differences, but troops on the ground need help to disrupt the aim of the bombers. If there's no AA or fighters the Japanese better send their troops where there is some.

[Alfred]

ORIGINAL: Bullwinkle58

ORIGINAL: Cribtop

Bullwinkle, I agree with your premise from a few posts back, namely in clear terrain the defender needs to move or dig in. I think one of the questions presented, particularly in PzB's example, is whether digging in, a/k/a fort levels, is sufficiently modeled to reduce bombing effects.

Field forts, the number on the top left of the LCU screen, have always been assumed, and I believe sorta kinda dev confirmed, to be basic, crude structures. Slit trenches, log bunkers, maybe some sandbags. Combat engineer stuff. Nothing permanent, certainly no concrete. Some of these structures help against shrapnel. A lot less against overpressure and heat/flame. When I bomb ground formations, and there's flak, or fighters, or both I don't wipe out half divisions. I'm using B-29s to bomb in Java and Sumatra now, and they face both sorts of defenses. I get numbers more on the order of 15 diasabled and 2 KIA squads for 30 B-29s from 10,000 feet. Yes there are terrain differences, but troops on the ground need help to disrupt the aim of the bombers. If there's no AA or fighters the Japanese better send their troops where there is some.

Plus it is important to re-read post #113. Several important points which do not support Rader's claim seem to be ... ahem ... still conveniently overlooked in presenting the case. Like divisions forced to move in the open after being routed by Soviet divisions before being visited by hordes of B-29 at 6k feet with no AA or CAP. Can't help wondering whether the presented data points just happen to be these very same Japanese divisions already crippled with disabled squads and limited supply etc. Nah, such selective manipulation to buttress a claim that something is borked would never happen.

Alfred