Aerial Bombing Question

[stona]

This is exactly so. It's why the 8th Air Force attempted to plot a pattern for an entire Group.
It must be understood that any idea of precise bombing was long gone. Nobody was pretending that an individual building or facility could aimed at or be hit at will by successive individual aircraft. If it was the aiming point, and if a Group bombed accurately, then enough bombs would fall close enough to the aiming point to more or less guarantee a result.
As the 8th Itself explains in its 1943 analysis of bombing operations.

"...The necessity for this arises from the fact that the combat conditions in this Theater are such as to make it defensively impossible for individual aircraft to bomb, one at a time, a given target. Our bombers are forced to attack from tight defensive formations, the basic unit of which has been the Group, comprising up to 21 aircraft. In consequence, in formation bombing we are concerned primarily with the pattern or the Group bomb fall as a whole rather than with the individual bombs dropped by the several aircraft."

Underlined in the original.

What you have here is a description of a form of area bombing, though at the time this was written (October 1943) no such phrase would have been used by the USAAF.

Cheers

Steve

 

[Greg Boeser]

Biff and Wuzak,
That's what I get for making quick replies. Mea Culpa.

 

[Zipper730]

You would have problems if they released from the top first.

Common sense enough...

But it is still not what I was saying.

For a B-17 to have 20 bombs on board they would be held on 4 racks - possibly 6 each on the inner racks and 4 each on the outer racks.

I'm starting to get punchy from being up a little late: To be clear, racks have shackles or shackles got racks?

So the time taken to drop all is not 20 times the interval between bombs. More like 6 times.

Which would be mean they would all come out in six seconds and drape an area around 2200 feet long?

In the analyses 'gross errors' were usually discounted.

OK

How an analysis was done was dependent upon the type of mission and many factors. In the example I gave above (H2X through cloud cover) any bombs that fell more than five miles from the target were ignored. This figure for bombs that were simply ignored is substantial. In the worse case scenario, bombing blind on H2X through 10/10 cloud, 41.5% of bombs fell more than five miles from the aiming point and were discounted.

And they called this precision bombing... lol

The Americans used 'Group Pattern ' analysis in which a single set of error measurements were calculated for the bombs dropped by an entire Group. The object was to establish how well the bombs were aimed. The Americans established a 'pattern center', defined as the centre of a circle with 1000' radius in which most of the bombs fell. It was the displacement of this point from the aiming point which was used to calculate the bombing errors.

So where it fell relative to the center of the ring was how they counted it?

The Americans had earlier attempted to use the Mean Point of Impact (MPI) to assess bombing errors. This was a method useful in some instances, like for example fighter bomber attacks on specific targets, but proved unsatisfactory for pattern analysis. The problem was that a relative few (2 or 3 from a Group of 21) stray 'sticks' of bombs falling outside the pattern might drag the MPI to the periphery of the main fall or even outside it.

So, the RAF factored each plane's bombing accuracy by itself?

It took some time for the British to realise that they simply couldn't navigate or bomb accurately by night

That was like 1941 right?

With bomber formations 500yd across and even wider, a lot of bombs are going to be spread out.

I know this might sound like a silly series of questions: At one point didn't they go from the combat box over the target area to a more amorphous formation to bomb; then go back into the box?

And why did they switch from the earlier combat box formation to this?

 

[stona]

And they called this precision bombing... lol

First it is important to define the difference between precision and area bombing. The problem is that the two are often (even usually) confused with a selective bombing offensive, in which a group of related target all associated with the same activity are engaged (Oil Plan, Transport Plan etc) and a more general bombing offensive. A selective offensive can in fact be pursued by either area or precision attack. It is a distinction lost on many historians, particularly, I'm sorry to say US historians.
Webster and Frankland describe the factors influencing the decision better than me.

"The choice between area and precision attack is primarily governed by operational factors; the choice between a selective and a general bombing offensive is a question of strategy."

The USAAF pursued a selective bombing campaign and initially attempted to do this with precision raids. It was operational factors that inevitably lead to the selective campaign (which rarely deviated into anything like a general offensive) to be pursued by methods that looked a lot like area bombing.
The RAF also set out intending to carry out a selective campaign, despite the Trenchardist influence on its doctrine. The Western Air Plans certainly represent a selective campaign and the idea was that this be carried out by precision bombing. The difference between the two forces is that as the British were forced to give up any idea of precise bombing their strategy also shifted towards a more general bombing offensive which reached a zenith in Harris' area bombing campaign. Harris had to be cajoled into allowing his force to support the Americans in their selective campaign in the last two years of the war. He famously referred to the target systems of the various selective plans as 'panaceas'.

So where it fell relative to the center of the ring was how they counted it?

Not quite. Individual bomb strikes were not important, except to establish the centre of the pattern. It was the distance of the centre of the Group pattern from the aiming point which was used to assess how accurately a Group had bombed.

So, the RAF factored each plane's bombing accuracy by itself?
That was like 1941 right?

Aircraft produced a bombing photograph which gave the position of the aircraft when it released its load, from which the bomb fall could be calculated. The images from many aircraft were combined to give a diagram of what had been hit.
It was not just the photograph that was used. EVERY aircraft on the raid produced a 'Sortie Report' the data from which was passed from Squadron to Group and then to Bomber Command's Operational Research Section (ORS). In the limited space here I will note that the key data were, target attacked, bombs dropped, time, height, heading and airspeed at bomb release, what was in the bomb sight and the bomb aimer's and pilot's report. Based on this vast amount of data the ORS produced a time histogram of the raid, this sheet was known because of its size as the 'table cloth'. It depicted the raid as it happened, minute by minute. Each half inch square represented one sortie and contained information about that sortie (aircraft, aiming point, whether the bomb release photograph had been plotted, even the bomb load).
This method was used from its introduction until the end of the war, though the analysis of the raw data became increasingly sophisticated, as did the information included in the 'table cloth', notably once pathfinders were included and factors like time of burn for markers were added..
Bomber Command could and did completely miss target cities right up to the end of the war, though numerous factors meant that the force was much more effective and accurate in the last two years than previously. In mid 1942 between 20% and 30% of bombs fell within three miles of the aiming point, by late 1944 this figure was hovering around 90% and Bomber Command often bombed more accurately by night than the 8th Air Force by day. It was cloud that so severely limited the 8th Air Force, in 1944 a large majority of its raids were conducted through 7/10 cloud or heavier. That's the weather in NW Europe.

Cheers

Steve

 

[wuzak]

To be clear, racks have shackles or shackles got racks?

There are 4 racks in a B-17. The two main ones are the in the centre, while two others are at the outside.

Each bomb is hoisted on a rack and held in place with a shackle.

So each rack can hold several bombs.

Taken from this post by ww2restorer.

The release sequences are shown in the top right hand corner.

Which would be mean they would all come out in six seconds and drape an area around 2200 feet long?

Only if the interval was set to 1s.

I don't know what the interval was typically set to, but it was probably less than 1s.

As you can see, the maximum number of stations on a rack is 13, but even with the smallest bombs not all could be used.

 

[stona]

British bombers didn't generally have that problem!
A combination of bomb distributor and selector allowed bombs to be dropped from various stations at various intervals. The interval could also be adjusted manually (literally by stopping the distributor arm) when dropping ordnance, like incendiaries, with very different terminal velocities. A longer interval could be counted by the bomb aimer.
Special distributors were developed for pyrotechnic dropping pathfinders with intervals up to 8 seconds.
Cheers
Steve

 

[stona]

The maximum interval on the commonly used 16 and 32 way British distributors (Types VI and VII) was 0.5 seconds.

The scale on the selector starts at 0.05 secs and is marked in increments, 0.08 then 0.1 then continues around the outside in increments of 0.1 secs, subdivisions marked inside at 0.15, 0.25, 0.35 and 0.45 secs.
Cheers
Steve

 

[Zipper730]

First it is important to define the difference between precision and area bombing. The problem is that the two are often (even usually) confused with a selective bombing offensive, in which a group of related target all associated with the same activity are engaged (Oil Plan, Transport Plan etc) and a more general bombing offensive.

General bombing offensives basically mean city busting?

A selective offensive can in fact be pursued by either area or precision attack.

Which is defined whether the aiming is at specific targets, or a zone where the targets are known to be?

"The choice between area and precision attack is primarily governed by operational factors; the choice between a selective and a general bombing offensive is a question of strategy."

Operational factors would be navigational and bombardment accuracy, enemy defenses, and bomber escorts; Selective would be a desire to destroy specific industry and targets where the other is to bomb 'em and burn 'em 'till they quit.

The USAAF pursued a selective bombing campaign and initially attempted to do this with precision raids.

And that didn't work because of a lack of effective deep-penetration escort, stiffening enemy air-defenses, and accuracy that was sub-par...

The RAF also set out intending to carry out a selective campaign, despite the Trenchardist influence on its doctrine.

This was from September 1939 to some point in 1940? If I recall, they chose a selective bombing campaign because of the size of the bombing force, the PM's personal opinions, and FDR's requests to avoid attacks on civilians.

Starting in May, it seem Churchill was more willing to adopt attacks on population centers but wanted to make sure the public was behind it before he'd do it. By July plans for incendiary raids were drawn up, but it wasn't until the Coventry raids that political unacceptable became political inevitable.

The Western Air Plans certainly represent a selective campaign and the idea was that this be carried out by precision bombing. The difference between the two forces is that as the British were forced to give up any idea of precise bombing their strategy also shifted towards a more general bombing offensive which reached a zenith in Harris' area bombing campaign.

Actually by February 1941, there was a memorandum circulated that specifically stated that attacks on cities were aimed at demoralization by causing mass destruction and fear of death to the population down below.

Harris had to be cajoled into allowing his force to support the Americans in their selective campaign in the last two years of the war. He famously referred to the target systems of the various selective plans as 'panaceas'.

Yeah, he was remarkably stubborn.

Not quite. Individual bomb strikes were not important, except to establish the centre of the pattern.

That I seem to get

It was the distance of the centre of the Group pattern from the aiming point which was used to assess how accurately a Group had bombed.

Understood

Aircraft produced a bombing photograph which gave the position of the aircraft when it released its load, from which the bomb fall could be calculated. The images from many aircraft were combined to give a diagram of what had been hit.
It was not just the photograph that was used. EVERY aircraft on the raid produced a 'Sortie Report' the data from which was passed from Squadron to Group and then to Bomber Command's Operational Research Section (ORS). In the limited space here I will note that the key data were, target attacked, bombs dropped, time, height, heading and airspeed at bomb release, what was in the bomb sight and the bomb aimer's and pilot's report. Based on this vast amount of data the ORS produced a time histogram of the raid, this sheet was known because of its size as the 'table cloth'.

Why did we not do this?

Bomber Command could and did completely miss target cities right up to the end of the war

Chemnitz right?

In mid 1942 between 20% and 30% of bombs fell within three miles of the aiming point, by late 1944 this figure was hovering around 90% and Bomber Command often bombed more accurately by night than the 8th Air Force by day.

What yielded this increased accuracy?

There are 4 racks in a B-17. The two main ones are the in the centre, while two others are at the outside.

So the walls are the racks...

Each bomb is hoisted on a rack and held in place with a shackle.[/quote]And each station has a shackle?

 

[wuzak]

So the walls are the racks...

No, the racks are the racks. The "wall" is round.

Each bomb is hoisted on a rack and held in place with a shackle.

And each station has a shackle?

No.

Only the stations that they are using would have shackles.

 

[wuzak]

View: https://www.youtube.com/watch?v=MHz3DBwYVyo


This is loading bombs into a B-29.

Generally similar to the B-17, I believe.

What we have been calling the shackle is attached to the bomb before it is hoisted into position, and that then connects to the rack.

The hoisting starts at around 3:00 or 3:30, the connecting of the shackle to the rack happens around 4:45.

For the Silverplate B-29s the normal racks were removed and a new type of rack installed.

 

[stona]

General bombing offensives basically mean city busting?
Which is defined whether the aiming is at specific targets, or a zone where the targets are known to be?
Operational factors would be navigational and bombardment accuracy, enemy defenses, and bomber escorts; Selective would be a desire to destroy specific industry and targets where the other is to bomb 'em and burn 'em 'till they quit.
And that didn't work because of a lack of effective deep-penetration escort, stiffening enemy air-defenses, and accuracy that was sub-par...
This was from September 1939 to some point in 1940? If I recall, they chose a selective bombing campaign because of the size of the bombing force, the PM's personal opinions, and FDR's requests to avoid attacks on civilians.

No. A selective campaign targets what we would now call target systems, oil, ball bearings, transport etc. The USAAF with rare exceptions always adopted this policy. A general bombing offensive might target far more nebulous objectives like enemy morale. In the case of the British effort it was an offensive to reduce German war production by any means possible. It degenerated into city busting, Harris is on the record stating that he was more interested in the acreage destroyed than factories flattened.

The method employed for a selective campaign might be precision or area bombing. The operational factors you identify determine which is achievable and whether there really is a choice. If you cannot reliably find or hit a relatively small target accurately (precision bombing)then you drop a lot of bombs in the area of that target in the expectation of hitting it (area bombing). The British (and I'm sure the American) did a lot of statistical analysis to work out how many sorties and what weight of bombs were required to guarantee the destruction of various targets.

The British chose a selective bombing campaign, as drawn up in the Western Air Plans because they thought it was the best application of the available air power. The re-think came when they realised that most crews couldn't find their targets, let alone hit them. The idea of a more general campaign was not new. For example, in WW1 the British attempted to bomb German or German occupied railway stations, but were not to bothered if the bombs missed the target and caused panic and damage elsewhere in the city/town. It was not considered a waste of effort.
You have to understand the bomber fleets of the major pre-WW2 powers as a deterrent. Everybody started with the intention of attacking purely military targets, not targeting civilians, in fact making a conscious effort to avoid civilian casualties. It wasn't long before this moral position started to slip on all sides and the RAF in particular had always had a strong influence from the Douhet/Mitchell/Trenchard line of doctrine. The RAF could not decide bombing policy in isolation, Britain is and was a democracy, not a military dictatorship. The gloves could only come off once sanctioned by the British government. By late 1940, much earlier than most appreciate, Bomber Command was pursuing its selective campaign by area bombing methods. On 30th October 1940, before Coventry was attacked, Sholto Douglas was writing to Peirse regarding attacking German towns and concluding

"The objectives considered most suitable for these concentrated attacks [on towns] are the sources of power, such as electricity generating stations and gas plants, and centres of communications; but where primary targets such as the oil and aircraft industry objectives are suitably placed in the centres of the towns or populated districts, they also might be selected."

One glove was already off.

Coventry was bombed on 14th November 1940 and Mannheim was the British city chosen for reprisal for this attack, and also for the heavy raids on Southampton. The raid took place on the night of 16/17 December under the code name Operation Abigail Rachel. Bomber Command was given a special authorisation by the War Cabinet to carry out a 'general attack on the centre of a German city', and it was Bomber Command that chose Mannheim. 134 aircraft were sent to Mannheim (reduced fron the intended 200 )and did bomb the city, most bombs falling in residential areas, killing 34 people and injuring another 81. The special authorisation was precisely because, at this time, the British were still prosecuting a selective campaign.
British bombing policy evolved through 1941, there is a series of reports and mamoranda published in Volume IV of the official history, but any in depth discussion of these is beyond the bounds of a forum reply. On 18th August 1941 the infamous Butt Report was published, which showed just how inaccurate and ineffective Bomber Command's efforts had been.

Starting in May, it seem Churchill was more willing to adopt attacks on population centers but wanted to make sure the public was behind it before he'd do it. By July plans for incendiary raids were drawn up, but it wasn't until the Coventry raids that political unacceptable became political inevitable.
Actually by February 1941, there was a memorandum circulated that specifically stated that attacks on cities were aimed at demoralization by causing mass destruction and fear of death to the population down below..

The debate about morale attacks did not really gather pace until May/June 1941 when Trenchard himself produced a memorandum advocating German morale as Bomber Command's primary target. On 2nd 1941 June Sir John Gill, Chief of the Imperial Staff, commented on the memorandum.

"1. Lord Trenchard makes two points

(a)That our primary bombing target should be German morale
(b) That the building up of a strong bomber force should be given the highest priority.

The primary bombing target
2. There is, I think, general agreement that the Battle of the Atlantic must remain our chief preoccupation: after that our effort should be employed against the most profitable targets in Germany. The possibilities are:
(a) Morale
(b)Oil
(c) Transportation
The arguments in favour of attack on morale are set out in Lord Trenchard's paper" [Beyond the scope of a reply here].

Note that morale is top of the table. The debate continued for months, and it wasn't until 14th February 1942 (not 1941) that AVM Bottomley (Deputy Chief of the Air Staff) wrote to AM Baldwin (Acting AOC-in-C Bomber Command, pending Harris' arrival) instructing him that

"...it has been decided that the primary objective of your operations should now be focussed on the morale of the enemy civil population and in particular of the industrial workers."

Just one sentence in a directive of several hundred words, but now the gloves were really off. It had taken two and a half years of war before it happened.

Cheers

Steve

 

[stona]

What yielded this increased accuracy?

I missed this one

Bomber Command's accuracy increased with improvements in operational efficiency.
There were many factors. Better training, better tactics, better and improved technology. This encompasses everything from 'broadcast winds' to Gee and H2S to the establishment of a path finder force and the complicated ballet of marking, backing up and main force bombing, all overseen by a master bomber, that typified a major raid in 1944/45.

Bomber Command almost overcame the problem of seeing in the dark, but like its American 8th AF ally, never overcame the vagaries of European weather.

Cheers

Steve

 

[wuzak]

The primary bombing target
2. There is, I think, general agreement that the Battle of the Atlantic must remain our chief preoccupation: after that our effort should be employed against the most profitable targets in Germany. The possibilities are:
(a) Morale
(b)Oil
(c) Transportation

Interesting that (b) and (c) were the target systems which would turn out to be, probably, the most important targets and which would give the most decisive results - for the war effort.

Was the RAF's capabilities, at that time, a major reason that Morale was put to the top of the list?

 

[stona]

Oil and transport systems featured in the Western Air Plans and along with an arguably more general target in 'the German war industry', meaning targets in the Ruhr, formed the backbone of Britain's strategic campaign. Other Plans had objectives like delaying '..a German invasion of southern Holland, Belgium and France' and we know how well that went.
Bomber Command was certainly attempting a selective campaign against such target systems, albeit using area bombing techniques, throughout 1940 and into 1941. It was really the Butt Report, which demonstrated that Bomber Command was incapable of hitting these or any other targets that concentrated minds.

Trenchard made this point in the memorandum I mentioned above. I can't reproduce the whole thing here, but having outlined why the British are better at withstanding casualties than other nations, nonsense that he obviously believed at the time, he makes the core argument in this extract.
Excruciating prose alert, Trenchard was not one for a short concise sentence

"Taking all in all the percentage of Bombs which hit the Military target at which they are aimed is not more than 1% .
This means that, if you are bombing a target at sea, then 99% of your bombs are wasted, but not only 99% of the bombs are wasted, but 99% too, of the pilots and the training which went to produce them, and of all the machines and the labour and plant and raw material which went into their construction, and, further back, 99% of all the ships which have transported the raw materials and of the finance which purchased these raw materials are all equally wasted. So, too, if the bombs are dropped in Norway, Holland, Belgium or France, 99% do Germany no harm, but do kill our old allies, or damage their property or frighten them or dislocate their lives. It is more than wasted. If, however, our bombs are dropped in Germany, then 99% which miss the military target all help to kill, damage, frighten or interfere with Germans in Germany and the whole 100% of the bomber organisation is doing useful work, and not merely 1% of it.
So technical factors also point to the wisdom of striking at what is in fact Germany's weak point. We should therefore exploit to the uttermost this vulnerable spot in the German nation and we should bomb persistently military targets in every town in Germany and never let up on them."

This is really no more than a re-hash of the plan developed in 1917 by the Air Policy Committee, to terrorise the German civilian population, and points made in Trenchard's own 1919 despatch on the Independent Force's operations. It has been argued (notably by H A Jones) that Trenchard's retirement led to confusion over what exactly the RAF bombing policy should be, but with a vague notion that an attack on enemy civilian morale existed as a back up option should others fail.

As early as July 1941, just a month later, Bottomley was writing to Peirse that

"I am directed to inform you that a comprehensive review of the enemy's present political, economic and military situation discloses that the weakest points in his armour lie in the morale of the civil population and in his inland transport system."

There are literally hundreds of documents on the record throughout this period which all demonstrate a general slide into what would become Bomber Command's general bombing offensive, prosecuted by an area bombing campaign. The best source for these is not the very small selection I can quote in short forum replies, hopefully to illustrate this process, but in Volume IV (annexes and appendices) of the official history in which many are reproduced.

Cheers

Steve

 

[stona]

This is an immense subject, I've spent years trying to understand it, and there are a few points I need to make, explanatory to those above.
First, the predisposition to bomb civilians in order to destroy their morale never left the RAF. In the inter-war years it resurfaced in 1923 as an official policy (as a response to the French air scare*) and would again, during WW2, in 1942. It was reinforced by aerial operations in colonial policing, so called 'air control', which was dependent on a willingness to bomb civilians. Between 1927 and 1935 an area bombing mentality informed the major manoeuvre exercises carried out by ADGB.
Within Bomber Command and the RAF, not the British government which was guided to a similar conclusion by a different route, it was always assumed that the precision campaign against military and industrial targets in Germany would only continue as long as Bomber Command remained too weak to launch a Trenchardian offensive against enemy cities. This is why the second point of Trenchard's 1941 memorandum emphasised the need for the build up of bomber forces. The Western Air Plans were designed to exploit the then available air power as best possible. They were designed not from a position of strength but of weakness. The move to a Trenchardian offensive came in 1942/43 as the Command started to gain sufficient strength. It had NOTHING to do with the coincidental appointment of Harris who somehow seems to get 'blamed' for it .
Cheers
Steve
* The then Major Archibald Sinclair made a long speech in parliament during the 'Air Estimates' debate (funding of the RAF) which sums this up better than I can. Check Hansard online.

 

[Graeme]

Thread drift, but an interesting list of possible reasons for bombing errors - RAAF bombing manual 1943...

 

[stona]

That's an interesting report. It has to be said that almost all of those errors should have been addressed in basic and operational training.
Bomber Command did much research into bombing accuracy and certainly acknowledged the classes of error listed above. It, however, considered the largest error, particularly contributing to under shooting and 'creep back' to be psychological rather than physical. Many crews saw what the wanted to see and if they saw something that looked like a target, then that was good enough. These errors occurred randomly throughout the crews attacking, but the cumulative effect was a systematic undershooting error.
This conclusion was included in a list sent out to the Bomber Groups which included other major sources of error. Pilots were considered to often approach the target taking no account of wind drift, and this could play havoc with the tracking system in the bomb sight, no matter how well the bomb aimer attempted to use it. Many bomb aimers thought that lobbing their bombs anywhere among the TIs was good enough, and that it was better to aim for an area where there was no fire rather than contributing to a target already engaged. This led to the completely unfounded charge by Bennett that half the main force crews didn't even use their bomb sights!
Bomber Command termed these errors 'blitz-consciousness' and they could not for the most part be overcome by better training. The errors were mitigated by improved marking techniques (they never spread the same way twice and it was considered important to have the track pass directly over the target) and the position of the TIs. For Oboe marking it was decided to place the TIs 11/4 miles ahead of the 'Command Aiming Point' and also to adjust for cross winds, regardless of strength, by placing the markers upwind by 1/2 a mile. For H2S marking the markers were placed a full 2 miles ahead of the Command Aiming Point.
Cheers
Steve

 

[mcoffee]

Two documents that should answer a lot of the questions regarding bombing:

Bombardiers Information File
Bombardiers' Information File : United States. Army Air Forces. Office of Flying Safety : Free Download & Streaming : Internet Archive

Terminal Ballistics Data, Vol I
Terminal ballistic data, volume I, bombing. :: World War II Operational Documents

 

[swampyankee]

One thing to remember is that factories, even without special hardening are not fragile. The USAAF probably overestimated how easily a factory could be destroyed; a lot of the machines would survive, undamaged, near-misses that would kill everybody in the factory. Much like aircraft and pilots, factories' skilled -- and even semi-skilled -- workers are harder to repair and replace than the machines.

 

[Zipper730]

No, the racks are the racks. The "wall" is round.

Ok

Only the stations that they are using would have shackles.

So the stations are attached to the racks, and a shackle is where bomb meets station?

For the Silverplate B-29s the normal racks were removed and a new type of rack installed.

They also redesigned the bomb-bay correct?

No. A selective campaign targets what we would now call target systems, oil, ball bearings, transport etc.

Okay, I understand

A general bombing offensive might target far more nebulous objectives like enemy morale.

Straight forward enough

In the case of the British effort it was an offensive to reduce German war production by any means possible. It degenerated into city busting, Harris is on the record stating that he was more interested in the acreage destroyed than factories flattened.

Actually there seemed to be primary desire to bomb the population, with industrial objectives being a bonus in such cases, unless specifically added.

Harris said that he was told to not bomb anything unless told to do so and waste the cities. While my view of Harris isn't generally positive, I'll say that he was one of the most honest and tried to remotely tell the truth.

The method employed for a selective campaign might be precision or area bombing. The operational factors you identify determine which is achievable and whether there really is a choice. If you cannot reliably find or hit a relatively small target accurately (precision bombing)then you drop a lot of bombs in the area of that target in the expectation of hitting it (area bombing). The British (and I'm sure the American) did a lot of statistical analysis to work out how many sorties and what weight of bombs were required to guarantee the destruction of various targets.

We both did...

The British chose a selective bombing campaign, as drawn up in the Western Air Plans because they thought it was the best application of the available air power. The re-think came when they realised that most crews couldn't find their targets, let alone hit them.

There was a book called "Almost a Boffin" in which an officer described USSR penetration of the RAE; additionally Richard Overy described some errors with filming the bomb-drop.

My guess is that the Soviet penetration ended in 1941...

The idea of a more general campaign was not new. For example, in WW1 the British attempted to bomb German or German occupied railway stations, but were not to bothered if the bombs missed the target and caused panic and damage elsewhere in the city/town. It was not considered a waste of effort.

Actually, in at least one case they wanted to set a city on fire; another they wanted to deliberately drop bombs sloppy to pound the population.

In some cases the population was the target, and the specified target the bonus

You have to understand the bomber fleets of the major pre-WW2 powers as a deterrent.

If I recall, there was a general fear that any declaration of war would be met with an annihilating attack with bombs, incendiaries, and poison gas. They seemed to actually view poison gas as the biggest threat. Fortunately the Germans and UK never used them.

Everybody started with the intention of attacking purely military targets

The RAF made such a decision because their bomber fleets weren't big enough, as well as Chamberlain viewing it as a war-crime. The Luftwaffe seemed to attack air-fields first, but soon was hammering the daylights out of Warsaw from what I remember.

It wasn't long before this moral position started to slip on all sides and the RAF in particular had always had a strong influence from the Douhet/Mitchell/Trenchard line of doctrine. The RAF could not decide bombing policy in isolation, Britain is and was a democracy, not a military dictatorship.

Yes but when the circumstances "work out" political impossible becomes inevitable. Modern day most say it as "never waste a good crisis", but the principle is the same. Churchill seemed interested in bombing cities by May, 1940 and wanted to gauge the public reaction; by July, Abigail Rachael was starting to be drawn up.

The gloves could only come off once sanctioned by the British government. By late 1940, much earlier than most appreciate, Bomber Command was pursuing its selective campaign by area bombing methods. On 30th October 1940, before Coventry was attacked, Sholto Douglas was writing to Peirse regarding attacking German towns and concluding

"The objectives considered most suitable for these concentrated attacks [on towns] are the sources of power, such as electricity generating stations and gas plants, and centres of communications; but where primary targets such as the oil and aircraft industry objectives are suitably placed in the centres of the towns or populated districts, they also might be selected."

One glove was already off.

Correct

Coventry was bombed on 14th November 1940 and Mannheim was the British city chosen for reprisal for this attack, and also for the heavy raids on Southampton. The raid took place on the night of 16/17 December under the code name Operation Abigail Rachel.

Yup, but the plan was drawn up in July of that year... around the time the Battle of Britain started.

I don't know if Churchill realized the raid on 8/24 was an accident or not and simply saw it as an opportunity to hit Berlin with the hopes that Hitler would go apeshit (not a hard conclusion to make) and divert attacks off the air-fields and onto the city; thus justifying the city-busting raids that would follow (This might be my modern views flavoring things -- I've openly said that "there's no such thing as an innocent politician" online, and view most politicians as sociopaths until I can prove they're not) and also taking the heat off the RAF, or; he thought they were deliberate and retaliated as war plans stipulated (attack airfields if cities get hit).

Bomber Command was given a special authorisation by the War Cabinet to carry out a 'general attack on the centre of a German city', and it was Bomber Command that chose Mannheim. 134 aircraft were sent to Mannheim (reduced fron the intended 200 )and did bomb the city, most bombs falling in residential areas, killing 34 people and injuring another 81. The special authorisation was precisely because, at this time, the British were still prosecuting a selective campaign.

I didn't know a special authorization was required, I do know the media was asked to be silent on it.

The debate about morale attacks did not really gather pace until May/June 1941 when Trenchard himself produced a memorandum advocating German morale as Bomber Command's primary target.

I'd almost swear I read a document dated February 23, 1941...

On 2nd 1941 June Sir John Gill, Chief of the Imperial Staff, commented on the memorandum.

"1. Lord Trenchard makes two points

(a)That our primary bombing target should be German morale
(b) That the building up of a strong bomber force should be given the highest priority.

The primary bombing target
2. There is, I think, general agreement that the Battle of the Atlantic must remain our chief preoccupation: after that our effort should be employed against the most profitable targets in Germany. The possibilities are:
(a) Morale
(b)Oil
(c) Transportation

Was there any point at which the RAF risked being truly dismembered?

The debate continued for months, and it wasn't until 14th February 1942 (not 1941) that AVM Bottomley (Deputy Chief of the Air Staff) wrote to AM Baldwin (Acting AOC-in-C Bomber Command, pending Harris' arrival) instructing him that

"...it has been decided that the primary objective of your operations should now be focussed on the morale of the enemy civil population and in particular of the industrial workers."

That sounds correct

Just one sentence in a directive of several hundred words, but now the gloves were really off.

Correct

I missed this one

Bomber Command's accuracy increased with improvements in operational efficiency.
There were many factors. Better training, better tactics, better and improved technology. This encompasses everything from 'broadcast winds' to Gee and H2S to the establishment of a path finder force and the complicated ballet of marking, backing up and main force bombing, all overseen by a master bomber, that typified a major raid in 1944/45.

When you say "broadcast winds", do you mean get wind-data while in flight so you're up to date?

Bomber Command almost overcame the problem of seeing in the dark, but like its American 8th AF ally, never overcame the vagaries of European weather.

That problem affected everybody eh?