Aerial Bombing Question

[stona]

The British used individual bombing photographs, along with other data from each aircraft, to build up the overall pattern of the bomb fall relative to the aiming point for the entire raid.

The Americans, bombing in daylight, could take fewer photographs or even film to show the bomb fall of each Group, easily extrapolated to generate an analysis of the entire raid.

Both air forces were trying to establish the same things, most importantly the concentration of the bombing and the accuracy of the bombing.
A good result depended on both these factors. There was no point in achieving a good concentration several miles from the target (inaccurate). Nor was there much good in spreading bombs widely, with the aiming point in the centre of the distribution (poor concentration). Neither stood any chance of destroying the intended target.

Concentration in time was also important, particularly to the RAF which had worked out that for incendiaries to be most effective (the bulk of ordnance carried for a typical area raid) they needed to be dropped in substantial quantities as quickly as possible in order to start a really good fire. Bomber Command became really proficient at this. In the famous Dresden raid 5 Group, which bombed first, dropped 881 tons of assorted ordnance on the city in just 15 minutes (22.13 - 22.28).
Let's put that 881 tons into some kind of perspective. 5 Group dropped 172 x 4,000lb 'cookies', 26 x 2,000lb HC bombs, 72 x 1000lb bombs, 648 x 500lb bombs, 197,178 4lb incendiary bombs and 8,250 4lb incendiary bombs with explosive charges (to discourage fire fighters). This was just the first wave.

No 8 (PFF) Group bombed between 1.21 and 1.45. Its 60 Lancasters included the master bomber, markers and illuminators and backers up. Along with the 10 tons of various markers it dropped 27 x 4,000lb 'cookies', 94 x 1,000lb bombs and 159 x 500lb bombs for a total of 125.7 tons of explosive.

No 1 Group bombed between 1.23 and 1.53 with 248 Lancasters. It dropped 145 x 4,000lb 'cookies', 101 x 2,000lb HC bombs, 111 x 500lb bombs for 397.3 tons of high explosive. It also dropped 312,666 x 4lb incendiaries, a total of 558 tons of incendiaries.

No 3 Group bombed between 1.25 and 1.55 with 151 Lancasters. It dropped 1 x 8000lb 'super cookie', 119 x 4,000lb 'cookies', 84 x 500lb bombs, for a total of 234 tons of high explosives. It also dropped 130,492 x 4lb incendiaries, 233 tons of incendiaries.

No 6 Group bombed between 1.27 and 1.45 with 65 Lancasters. It dropped 65 x 4,000lb 'cookies', 374 x 500lb bombs and 155 x 250lb bombs, 217 tons of high explosives.

The first wave, No 5 Group comprised 240 Lancasters, bombing in 15 minutes. That is better than one aircraft bombing every four seconds.
The second wave comprised about another 550 Lancasters, all bombing between 1.21 and 1.55, just 34 minutes. Again, better than one aircraft bombing every four seconds. Imagine that for half an hour.

Modern commentators don't know what 'shock and awe' really looked like.

Edit: I've just done a quick sum to show that the 2,660 tons of ordnance dropped in two waves of 15 minutes and 35 minutes for a total of just 50 minutes, largely exceeds the roughly 2,000 tons per day average dropped and delivered (by missile) across all of Iraq during the 43 days of the Gulf War.

Steve

 

[Milosh]

Why the hell did we use formations this wide in 1944? Previously we were using 12 ship combat boxes one behind the other? At least that's a more narrow series of bomb-trains...

Formations were wider before 1944, Combat Box Formation For Bombers WWII - I Love WW2 Warbirds.com

 

[stona]

The 'bomber box' is a much misunderstood concept, in the sense that many fail to understand that it comprised much more air than it did aircraft.
The diagrams in that link do a good job showing this.
Cheers
Steve

 

[buffnut453]

Unless I misunderstood, or missed a detail: Is this the mean point of impact or is this something else? I'm just curious why they US didn't compute the bomb-accuracy for every plane as the RAF did? We could often see better than they did...

"Mean point of impact" is the average centre point of where 50% of all bombs landed. In Bomber Command, each aircraft individually bombed the target, hence improving the value of measuring MPI across the entire raid. Obviously, other data were also gathered and statistics generated.

The US didn't compute bomb accuracy for every plane precisely because only few airframes carried a bomb aimer. Most of the bombers in a USAAF formation would toggle their bombs when the lead aircraft, with a bomb aimer, released it's load. Clearly one could calculate the MPI for the formation but it wouldn't tell you anything about the accuracy of bomb aiming across the formation/unit because everyone dropped based on one bomb aimer's decision.

 

[tyrodtom]

Have you ever seen a railroad switching yard, chemical plant, or major aircraft/vehicle assembly plant ?
They're huge, usually covering acres of land, it's not a pin-point target.

It's best and safest for the bombers if they can all drop their bombs as close to the same moment in time as possible, you overwhelm the target's defense with more aircraft than they can shoot down in a given amount of time.

 

[stona]

Have you ever seen a railroad switching yard, chemical plant, or major aircraft/vehicle assembly plant ?
They're huge, usually covering acres of land, it's not a pin-point target.

It's best and safest for the bombers if they can all drop their bombs as close to the same moment in time as possible, you overwhelm the target's defense with more aircraft than they can shoot down in a given amount of time.

Yes and no. In terms of WW2 bombing a target like those above, even covering many acres, was a precision target. Bombing accuracy was such that even in good conditions of visibility (in which a small minority of raids were carried out, 14% of USAAF raids in late 1944) it was difficult to hit such a target and achieve the concentrations necessary to destroy it. In such ideal conditions about 35% of bombs (say 1 in 3) fell within 1,000 feet of the aiming point, but that leaves 65% which fell further away, sometimes literally miles away.

Bomber Command worked out that to destroy the facilities of a typical marshalling yard (railroad switching yard) required a bombing concentration of three bombs per acre over the entire facility to give a 75% chance of disabling it. Given an acre measures 22 yards by 220 yards you don't need a calculator to work out that to achieve this, even in ideal conditions the USAAF was going to have to drop a lot of bombs, and that means flying a lot of sorties against the target.
It required the 'pattern centre' of several Groups to be close to the aiming point and it required the patterns themselves to be sufficiently concentrated. Neither of these was a given, or easily achieved.



Cheers

Steve

 

[buffnut453]

Have you ever seen a railroad switching yard, chemical plant, or major aircraft/vehicle assembly plant ?
They're huge, usually covering acres of land, it's not a pin-point target.

It's best and safest for the bombers if they can all drop their bombs as close to the same moment in time as possible, you overwhelm the target's defense with more aircraft than they can shoot down in a given amount of time.

I'm very familiar with the scale of the targets you mention but that has nothing to do with why the USAAF didn't need to measure the accuracy of each airframe.

Note that precision and accuracy are separate metrics. Dropping all the bombs at one time as aimed by one aircraft will achieve concentration of explosive force (i.e. good precision) but it may not achieve good accuracy. If the bomb aimer is off his game, then the entire formation will precisely bomb the wrong location. Bomber Command suffered its own problems, not least of which was aiming point creep as successive bombers toggled at the nearest edge of a conflagration rather than carrying on to the actual aiming point. However, the fact that each aircraft's aiming point was identified helped in the development of techniques and technologies to improve the situation.

 

[stona]

I'm very familiar with the scale of the targets you mention but that has nothing to do with why the USAAF didn't need to measure the accuracy of each airframe.

Note that precision and accuracy are separate metrics. Dropping all the bombs at one time as aimed by one aircraft will achieve concentration of explosive force (i.e. good precision) but it may not achieve good accuracy. If the bomb aimer is off his game, then the entire formation will precisely bomb the wrong location.

What you are calling 'precision' was more normally called 'concentration', certainly by the British, but the point is valid. Achieving a good concentration of bombs, at or better than three bombs per acre, a mile away from the targeted marshalling yard will not damage it at all. (It might damage something else, therein lies one of the roots of area bombing theory.)

It was possible to miss an entire city, and by some margin. The British did this by night, but the Americans did it by day, particularly in bad weather when the ground was invisible to them.
I have somewhere the bombing photograph plots for a late 1942 Bomber Command raid on Cologne. It shows a good concentration which might have inflicted some serious damage on the city, if only it could have been moved about 10 miles to the south west!

Cheers

Steve

 

[buffnut453]

Sorry...I was applying my training as a targeteer and the current parlance just slipped out. It took all my effort to not start discussing Target Systems Analysis and how a large target like a switching yard, chemical plant or factory can be taken out of commission without the need to flatten both it and the surrounding several thousand square yards of real estate. Trying my level best not to apply the retrospectroscope and judge WWII practices by modern techniques.

 

[tyrodtom]

My answer was more of a reply to zipper730 as to why they switched from groups in trail, to groups abreast.
It was trading survival of aircraft crews for bombing concentration.

When you bomb in trail, you're presenting the enemy with the opportunity to defeat you in detail, shoot you down one at a time.

When you go over the target in a brief time period, his AA defense has more targets in less time.

 

[stona]

My answer was more of a reply to zipper730 as to why they switched from groups in trail, to groups abreast.
It was trading survival of aircraft crews for bombing concentration.

When you bomb in trail, you're presenting the enemy with the opportunity to defeat you in detail, shoot you down one at a time.

When you go over the target in a brief time period, his AA defense has more targets in less time.

Yes, but their is always a balance to be struck. In the American case an approach by the bombers on a narrow front was much easier for the escort fighters to protect.

The British, when operating in daylight, wanted to shorten their bomber stream by broadening the front on approach from two to three miles, only converging three to five miles from the target to bomb, in an effort to reduce losses to flak. It was Fighter Command which pointed out that protection was much more effective on a narrow front.
The British did not fly in daylight formations like the Americans, but in a 'gaggle'. All the bomber Groups endeavoured to reduce the length of the gaggle to eliminate the tail, which automatically broadened the front, and in the end they were left to get on with it and the fighters had to deal with it. Even in daylight every bomber bombed by itself, quite unlike American practice.
By this time German resistance, certainly from Luftwaffe fighters, was nothing like that faced by the Americans eighteen months or so earlier in any case. Flak seems to have been a more important consideration.

Cheers

Steve

 

[Zipper730]

The British used individual bombing photographs, along with other data from each aircraft, to build up the overall pattern of the bomb fall relative to the aiming point for the entire raid.

The Americans, bombing in daylight, could take fewer photographs or even film to show the bomb fall of each Group, easily extrapolated to generate an analysis of the entire raid.

I assume it required greatly more manpower to compute it the RAF way?

I assume the USAAF could compute the accuracy of each formation or each plane?

Modern commentators don't know what 'shock and awe' really looked like.

Of course not, but that's exactly what the goal was: To kill hoards of people as spectacularly and brutally as possible and turn life at home into a living nightmare as frequently as possible. The idea was that the civilian population was the political center of gravity, and that's what should be battered to a bloody pulp.

The problem with the idea was that, morality aside (there's no point in bringing that up in something of this nature), such attacks usually created a greater desire for the people to rally around their government instead of turn on it. People also were usually concerned with escaping the insanity alive, so they usually fled the city, but didn't usually riot.

Dictatorships also have powerful measures in place to

• Shamelessly propagandize and brainwash a sizeable portion of the population so as to ensure compliance
• Arrest and detain trouble makers, and maintain the justification of this to the public
• Brutally subdue, kill and/or terrorize those who won't comply with the previous two

Technically even democracies use propaganda and brainwashing to varying degrees, and in wartime powerful forces exist, some of which are extrajudicial, to hold-down a population. The difference is mostly that dictators are not held back by things like rule of law (he is the law), or a written constitution -- in the event such a written constitution exists, it is useless in that it's almost never enforced. Will of the public is less of a concern.

When it comes to coercive tactics, it usually only works when the country is unable to protect itself from attack, or becomes unable to retaliate. This seemed to be the case in both Germany and Japan

• Germany was progressively torched and battered into ruin, as well as occupied from two sides: As a rule, morale collapsed the more the country was wrecked, however fighting continued right into the streets of Berlin. An exception being a brief period in 1944, when Goebbels revealed the so-called Morgenthau Plan to the German people (ironically the guy who came up with it was Harry Dexter White).
  
• Japan had suffered massive destruction of their Navy and Army in various campaigns against the US, the UK, Australia, and NZ military forces, including the loss of some of their best pilots despite having initiated the war with a devastating series of sneak-attacks. Starting in 1944, the US began a massive mine-laying operation and enlisted the USAAF to join in, which succeeded in sinking enormous amounts of shipping and deprived the islands of resources and food (this was actually regarded as so devastating that had it begun earlier, it was considered to have been a war winner on its own); B-29's also entered service the same year and started carrying out raids into Japan mostly aimed at industrial targets, though largely ineffectual, with one incendiary raid carried out that year; raids intensified into early 1945 with Tinian and Iwo Jima taken, and starting on March 9/10, massive incendiary raids started that systematically roasted something like 65 or 67 cities and killed hundreds of thousands of people. Their ability to attack the US was limited to using hot-air balloons carried along the jet-stream aimed at the hope of starting forest fires (something I'm surprised didn't work spectacularly well to be honest as a mentally ill individual in 2006 managed to set a forest fire that torched over a hair over 254 square miles, and a grade-A douchebag managed to set an unambiguously intentional fire that destroyed almost 63 square miles of surface area and killed five firemen, for which he was sentenced to death), though there were concerns about their deployment of biological agents (which they did deploy on China) which would have caused serious death tolls (which I'm surprised they never implemented, though relieved). Their defensive capability against the US was quite limited due to the fact that many of their aircraft did not have high operating altitudes or service ceilings (the J2M, Ki-60, Ki-84, and Ki-100 seemed to be the best candidates), their night fighter force was fairly small, and bombing raids hampered production. This all occurred before the dropping of the nuclear bombs on August 6, and 9th of 1945, and feelers were already being extended prior to this as well. The nuclear bombs accelerated the end of the war by a few weeks (according to General LeMay), to a couple of months (USSBS). The Japanese did supposedly test a nuclear bomb at Konan on August 10th, but the country was already in shambles, and I'm not sure what ability they had to deliver this weapon what distance.

Formations were wider before 1944, Combat Box Formation For Bombers WWII - I Love WW2 Warbirds.com

If I read this right, the 12-plane box was used first, then an 18-plane formation followed by a 27-ship formation, and eventually using several 18-ship formations side by side and then several behind each other if I look at this right, and then finally bringing it down into the 500 yd x 200 yd 36 ship formation.

I'm surprised they would need 36 aircraft to provide coverage for themselves once they got fighter escorts, you'd think they'd be better off by using a whole line or series of lines of 12-ship formations.

The US didn't compute bomb accuracy for every plane precisely because only few airframes carried a bomb aimer. Most of the bombers in a USAAF formation would toggle their bombs when the lead aircraft, with a bomb aimer, released it's load.

I thought that was only done in some cases?

 

[stona]

Manpower to debrief the crews, gather intelligence and interpret the bombing photographs was the least of the RAF's concerns. Assembling and understanding the data, interpreting it to make realistic assessments of every raid was just one vital aspect of the overall effort.
There were many, many cogs in the machine that was Bomber Command, some might be bigger than others, but they all had to work.
Cheers
Steve

 

[pbehn]

Some info on picture taking by Bomber Command.

Photo Flash Bomb

 

[Reluctant Poster]

The attached files are excerpts from the US Strategic Bombing Survey: Oil Division Report. Figure 7 illustrates how inaccurate WWII bombing really was. The table on page 4 of the report dispels the myth that the USAAF daylight raids were more accurate than the RAF night raids, in fact showing the opposite. Figures 6 & 8 demonstrate the greater effectiveness of the larger bombs dropped by the RAF. The larger bombs dropped by the RAF could, and sometimes did, permanently destroy a synthetic oil plant in one raid, which the USAAF could not do. A final point is that, according to the Germans, the longer duration of the RAF raids increased their destructiveness as damage control was not possible during the raid. Coupling all this with the fact, as been pointed out, that the RAF did devote a lot of effort to the oil campaign it is difficult not to come to the conclusion that the RAF deserves the lions share of the credit for the destruction of the German oil industry

 

[Reluctant Poster]

The attached files are 8 AF reports on bombing accuracy. One of the more eyeopening facts is that the B-24 was a far less accurate bomber than the B-17. This fact alone makes it clear as to why the 8th AF preferred the B-17 to the B-24.

 

[Reluctant Poster]

Charts comparing bombing accuracy of visual vs overcast.

 

[stona]

A final point is that, according to the Germans, the longer duration of the RAF raids increased their destructiveness as damage control was not possible during the raid.

Good stuff there, thanks for that.

Just to clarify the point above, the 'longer duration' was not of each phase of the raid, which could be as little as 15 minutes for a typical 250 aircraft (the mantra was concentration, concentration, concentration). It was for the overall length of the attack. It was because city area attacks attacks were often made in two separate phases with a gap of up to two hours between. It was entirely intentional because the British had worked out what the Germans knew from experience, that it limited efforts at damage control, notably fire fighting, and gave the best chance of a really destructive fire.
Cheers
Steve

 

[Robert Porter]

Take me awhile to digest this info but I thank you for it! Very interesting read!

 

[pbehn]

Good stuff there, thanks for that.

Just to clarify the point above, the 'longer duration' was not of each phase of the raid, which could be as little as 15 minutes for a typical 250 aircraft (the mantra was concentration, concentration, concentration). It was for the overall length of the attack. It was because city area attacks attacks were often made in two separate phases with a gap of up to two hours between.

There was also a compromise made between concentration of bombing and defence of the bombers. Maximum concentration would be by 1000 bombers crossing the target in 10 minutes but that would also be a wonderful environment for night fighters. The bomber streams did not always follow identical routes with the idea of giving the German defence the maximum number of problems to solve as far as how many planes to have in the air or coming back for refuelling/re arming.