High Altitude Bombing: how useful?

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wiking85

Staff Sergeant
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Jul 30, 2012
Chicagoland Area
Given how the trend toward the end of the war was toward higher altitudes to avoid AAA and make it harder for defensive fighters to perform, its seems like the altitudes were rising above 30,000 feet, especially if the B-29 was going to appear in Europe. But how useful was it to bomb at this altitude? What sort of accuracy could be achieved, because it seems like even at 27,000 feet and above only area targets could be hit with dumb bombs used en masse. With altitudes over 30k ft what could actually be hit? Would the attacker need to use even greater mass of bombs and hope to hit something useful by luck?
 
It was very effective if for no other reason than Daylight Strategic Bombing and the threat it represented caused several extremely important actions by Germany.

First, it forced a massive shift of critical resources to the Luftwaffe, and in particular to Day Fighters and anti aircraft artillery and the manpower to man them. The Luftwaffe bomber force was severely impaired due to the shifts .

Second, Speer was so concerned about the effect of destruction/damage to critical 'choke' resources like Ball Bearings and aircraft engines, that he ordered and executed a massive decentralization of those resources. The decentralization impaired both efficiency of assembly and also lag time to produce final product.

Third, several critical industries (Oil/Chemicals) were hit hard enough to affect both the air war and ground war.

Last - the fear of the consequences of unhindered assault on critical industry caused the Luftwaffe to throw 60% of its day fighters into the battle over Germany - and thereby lose far too many skilled pilots and crews to even have a hope of defeating the Normandy Invasion.
 
Fair summary.

One may add that the prospect of high altitude bombing triggered Germany to invest a HUGE amount of ressources into engeneering efforts trying to develop high altitude engagement solutions. These included Jet and rocket propelled A/C, several big gun AAA (15cm) projects, SAM and conventional but highly specialised high altitude interceptors like Ta-152H. Usually, these investments in R&D returned low or no benefit when the B29 just didn´t made advent.
 
My question wasn't about the response cost, but what actually it could achieve in terms of physical damage. It seems to me that bombing from that altitude is going to be lucky to even strike a city that isn't as large as Berlin or London. I'm aware that the Germans historically were worried about it, but in terms of actually accuracy did they really have anything to be worried about (short of an Atom bomb which was dropped from 30,000 feet).
 
With WWII era bomb sights only area targets can be hit from 20,000+ feet using iron bombs.

It was worse than that.

An analysis of the bombing in support of the allied landings post D-Day by the RAF heavies, mostly carried out from 12,000 and 13,000 feet, showed an average displacement of the mean point of impact of 420 yards. The average radial standard deviation of the bomb pattern (a measurement of the scatter of bombs within the bomb pattern) was 620 yards.
The RAF achieved a density of 10 bombs per acre at the centre of the bomb pattern. Only 30% of the ground at the centre of the pattern was cratered. In the opinion of the ORS the destructive effect of a high explosive bomb extended little beyond the crater, and this density was 'unimpressive'.

This is bombing from a relatively low altitude in day light. It is also a report on the ability of heavy bombers to operate in a ground support role where they were hoping that they would destroy very small targets like individual guns and their emplacements.

Results for the USAAF were similar but slightly worse.

From higher altitudes both these figures would be larger but still in the hundreds of yards. Area bombing could most definitely hit an area the size of a small city or town and with the advent of master bombers and other marking techniques to adjust the aiming point (unlike USAAF bombers every RAF main force bomber had a bomb sight and was expected to use it, you can't bomb on someone else's say so at night) and with several hundred bombers attacking, large areas could be, and were, devastated.

Cheers

Steve
 
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Very little prior to spring of 1944. There were a few notable exceptions such as bombing of Hamburg during July 1943 and Alkett during November 1943 but most pre-1944 Allied bombing raids were failures.
 
Very little prior to spring of 1944. There were a few notable exceptions such as bombing of Hamburg during July 1943 and Alkett during November 1943 but most pre-1944 Allied bombing raids were failures.


The people of a long list of German cities might disagree with you. The problem is quantifying the effect of the raids on German production. Many have tried and all have come to different conclusions. Most agree that production would have been greater (and different) had German cities not been subjected to an evermore accurate hail of bombs from.

Let's stick to the facts, reported by the Germans themselves rather than opinion. I'm not going to reproduce Bomber Command's war diary here but a couple of examples from 1942 will serve.

The first 'maximum effort' 1,000 bomber raid was of the night of 30/31 May 1942.
12,840 buildings were damaged of which 3,330 buildings were destroyed. Of these 2,560 were described as industrial or commercial (by the Germans). 36 large firms suffered complete loss of production. A further 70 suffered 50-80% loss and 222 up to 50% loss.
17 water mains, 5 gas mains, 32 main electricity cables and 12 main telephone routes were also destroyed. Very worrying to the German authorities was the exodus of between 135,000 and 150,000 of the cities 700,000 population.

The raid on Bremen on 25/26 June 1942 might not have been as dramatic but amongst the buildings destroyed was an assembly shop at the Focke-Wulf factory (16 others were damaged). As for other industrial facilities, the Atlas Werke, Vulkan shipyard, Norddeutsche Hutte and Korff refinery were also extensively damaged.

You might call that ineffective but the Germans did not. These large raids with hundreds of bombers carried on until August 1942.

The following year (1943) the RAF embarked on the 'Battle of the Ruhr'. I don't have time to give all the details, but again it is the Germans who did not consider it 'ineffective'. It was the success in these phases of the battle that led the RAF to embark on the 'Battle of Berlin' in late '43 and early '44. This was certainly a defeat for the RAF, even the official history more or less admits as much.

Cheers

Steve
 
There can be no doubt that they were effective. However, I keep the impression that they were inefficient, too. Effect only relates to the impact on target, efficiency relates to the investment to produce said impact.

There probably is a way to explore efficiency in terms of manhours pro and con. I once did that and estimated that the most efficient weapon platform -excluding the nuke- was probably the V1 and the most inefficient the V2.
 
Fair summary.

One may add that the prospect of high altitude bombing triggered Germany to invest a HUGE amount of ressources into engeneering efforts trying to develop high altitude engagement solutions. These included Jet and rocket propelled A/C, several big gun AAA (15cm) projects, SAM and conventional but highly specialised high altitude interceptors like Ta-152H. Usually, these investments in R&D returned low or no benefit when the B29 just didn´t made advent.

Kinda reminds one of the investment the USSR made to stop the B-70.. and President Kennedy did it for them with a walk and talk with General Lemay in the Rose Garden.
 
Occasionally the 8th AF performed some amazingly accurate 'pickle barrel' bombing under excellent weather/visibility conditions - to the extent of isolating a specific building/plant for the lead bomber to take out. A Catalytic Cracker in a refinery would be an example of a critical component in making aviation gasoline.
 
It was worse than of the scatter of bombs within the bomb pattern) was 620 yards.
The RAF achieved a density of 10 bombs per acre at the centre of the bomb pattern. Only 30% of the ground at the centre of the pattern was cratered. In the opinion of the ORS the destructive effect of a high explosive bomb extended little beyond the crater, and this density was 'unimpressive'.

This is bombing from a relatively low altitude in day light. It is also a report on the ability of heavy bombers to operate in a ground support role where they were hoping that that.

An analysis of the bombing in support of the allied landings post D-Day by the RAF heavies, mostly carried out from 12,000 and 13,000 feet, showed an average displacement of the mean point of impact of 420 yards. The average radial standard deviation of the bomb pattern (a measurement they would destroy very small targets like individual guns and their emplacements.

Results for the USAAF were similar but slightly worse.

From higher altitudes both these figures would be larger but still in the hundreds of yards. Area bombing could most definitely hit an area the size of a small city or town and with the advent of master bombers and other marking techniques to adjust the aiming point (unlike USAAF bombers every RAF main force bomber had a bomb sight and was expected to use it, you can't bomb on someone else's say so at night) and with several hundred bombers attacking, large areas could be, and were, devastated.

Cheers

Steve

Steve - there were good technical reasons for 8th AF Lead Crew methods. Simply put the burden of bombing accuracy on the shoulders of the proven best bombardier's shoulders. The RAF methodology was what 8th practiced in 1942 and Lemay's lead crew concept immediately improved overall accuracy, but more importantly it improved specific target (i.e. the Cat cracker analogy I used earlier) destruction probability.

When every squadron focused on a high value target within a complex, the probability of critical hits were improved.

The RAF had very good bombsights but I question the 'every man do his thing' concept that 8th AF discarded two years before.
 
My question wasn't about the response cost, but what actually it could achieve in terms of physical damage. It seems to me that bombing from that altitude is going to be lucky to even strike a city that isn't as large as Berlin or London. I'm aware that the Germans historically were worried about it, but in terms of actually accuracy did they really have anything to be worried about (short of an Atom bomb which was dropped from 30,000 feet).

A bit of an exaggeration ( but no worse than a bomb in a pickle barrel). Let's assume our airplane at 30,000 ft lets go a bomb over the center of a city that is circular in shape and 11.36 miles in diameter (101.36 sq miles). the bomb would have to travel on a 45 degree path in any direction to miss the city. Modern Berlin is 344 Sq miles, Greater London is over 600 sq miles.
Hitting a 100 ft circle from 30,000 ft is just about impossible. Missing a city, assuming you can find the center of it to begin with ( do not confuse navigation errors with bombsight errors) is almost equally impossible.

Lets take Stona's numbers again 420 yd average error from 12,000ft times 2 1/2 for 30,000ft = 1050 yds and then lets double it just as a fudge factor for extra cross winds and such and we have a 2100 yd average error. Or about 1.2 miles average error. Unless the city is smaller than 2.4 miles in diameter it has a problem, and even then please remember average error. for every bomb that landed 800 yds from the target point one had to land only 40 yds from the target point to get a 420 yd average.

Problems in bombing from 30,000ft include a higher probability of cloud cover obscuring target changing bomb "aiming" to bomb drop and "praying". More difficulty in estimating ground speed throwing of the bombsight calculations. Finding the target in the first place with the cloud cover. Clouds and bad weather can save you from some raids but NOT ALL. Bombers operating at 30,000ft could not be ignored and depending on the attackers poor accuracy is a pretty poor defense.
 
Alkett was seriously damaged during the "Battle of Berlin", one of the most effective bombing raids of the war. Was that intentional or did the RAF just get lucky that night?
 
the degree of acceptable efficiency was directly proportional to acceptable losses. the 8th af knew back then pretty much how well they were striking the target. recon photos taken after the mission were accessed and told them what the success rate was. you can increase accuracy and success by bombing at lower alts....but you place your bombers in airspace that is more hazardous...losses increase due to them being where the LW fighters have a better performance envelope and flak will be more accurate. how long are you willing to or can sustain that rate of loss? and how great an increase in accuracy/efficiency will you see? is that specific target worth what you will lose in manpower, machinery, and morale?
 
Steve - there were good technical reasons for 8th AF Lead Crew methods. Simply put the burden of bombing accuracy on the shoulders of the proven best bombardier's shoulders. The RAF methodology was what 8th practiced in 1942 and Lemay's lead crew concept immediately improved overall accuracy, but more importantly it improved specific target (i.e. the Cat cracker analogy I used earlier) destruction probability.

When every squadron focused on a high value target within a complex, the probability of critical hits were improved.

The RAF had very good bombsights but I question the 'every man do his thing' concept that 8th AF discarded two years before.

Every man had to do his own thing because the majority of raids were at night when it is obviously impossible to fly formation and bomb on the say so of a lead bombardier. Bennett once claimed that less than half main force crews were bothering to do so!

The ORS looking at the support missions post D-Day thought that the US system was one of the principal reasons that the USAAF bomb patterns were less concentrated, if only by a small margin.
Again I must emphasise that these ORS were looking at the ability to destroy individual small targets with the heavy bombers, things that required a more or less direct hit, hence the importance of bomb density. This would not apply to a target like a refinery or factory complex, though it would apply to something like a machine tool.

Cheers

Steve
 
Alkett was seriously damaged during the "Battle of Berlin", one of the most effective bombing raids of the war. Was that intentional or did the RAF just get lucky that night?

There would be an element of luck, hitting anything specific, whilst statistically possible was never a probability using night time area bombing tactics.

Berlin was seriously damaged in this period. German reports actually show that the damage was heavier than Bomber Command suspected, but that's not the point. Harris' objective was much more far reaching, nothing less than forcing a German surrender by April 1944, and this he didn't come close to achieving.

Despite the rapid development of Bomber Command tactics (dummies and feints using 'window', ignoring Sweden's neutrality, more and more indirect routes, shortening of the bomber stream to the extent that 800 bombers could pass over Berlin in 20 minutes, increasing radio countermeasures and intruder forces, establishment of 100 (Bomber Support) Group and many more) losses remained unsustainable. German tactics also evolved and between mid November 1943 and January 1944, when the main thrust of the offensive turned away from Berlin, 385 bombers had been lost on 7,403 sorties.

It was a defeat not because Berlin wasn't substantially damaged but because it failed to achieve the objective set out by Harris and because losses were unsustainable.

Cheers

Steve
 
Every man had to do his own thing because the majority of raids were at night when it is obviously impossible to fly formation and bomb on the say so of a lead bombardier. Bennett once claimed that less than half main force crews were bothering to do so!

The ORS looking at the support missions post D-Day thought that the US system was one of the principal reasons that the USAAF bomb patterns were less concentrated, if only by a small margin.
Again I must emphasise that these ORS were looking at the ability to destroy individual small targets with the heavy bombers, things that required a more or less direct hit, hence the importance of bomb density. This would not apply to a target like a refinery or factory complex, though it would apply to something like a machine tool.

Cheers

Steve

Steve - my comments were directed toward daylight raids conducted by RAF in 1944/1945.

IIRC the ORS looked at all 8th AF raids including H2X (blind bombing as far as 8th concerned) directed bombing through 10/10. The 8th never attained the same proficiency as the RAF for such attacks.

In almost every case the 8th went back to those targets in better visibility.
 
Steve - my comments were directed toward daylight raids conducted by RAF in 1944/1945.

IIRC the ORS looked at all 8th AF raids including H2X (blind bombing as far as 8th concerned) directed bombing through 10/10. The 8th never attained the same proficiency as the RAF for such attacks.

In almost every case the 8th went back to those targets in better visibility.

Yes, RAF daylight raids. I suppose that they weren't going to change the system with which they'd been working for nearly five years :)

I think, but I'm not absolutely sure without digging out the original sources, that the ORS comparison was done for raids on Caumont by the 'heavies' of the two air forces. I wouldn't make too much of the rather small difference in results for such a limited sample.

Not relevant to high altitude heavy bombers, but medium bombers were only slightly more accurate. Between June and August 1943 mediums of the RAF Desert Air Force were bombing with a probable radial error of 330 yards. In June 1944 mediums of the Mediterranean Allied Tactical Air Force (MATAF) were bombing with a probable radial error of 170 yards. Crucially the bomb density on point targets achieved by mediums for a given number of bombs was 2 1/2 times that of the heavies. It didn't mean they could hit anything reliably. To ensure a 95% chance of hitting a typical bridge target of 6,000 square feet the MATAF mediums would have to drop 600 bombs. The poor old Desert Air Force would have needed to drop 2,400 !

A bit of a diversion, but it is important to emphasise just how difficult it was to hit relatively small targets without dropping huge quantities of bombs. It's the reason that area bombing was originally adopted by the RAF and later by the USAAF (whatever it liked to pretend, or whatever euphemisms it used).

Cheers

Steve
 

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