Daylight strategic bombing: German ball bearings

[Grittis]

I am reading "Vanishing Act" by Dan Hampton (2024) which describes in detail the aftermath of the Doolittle raider which landed in Russia after bombing Japan on 18 Apr, 1942. While the raid itself has been dealt with in detail by a number of authors, and Lt. Col. Hampton has broken some new ground, my interest is in one specific assertion he makes about strategic bombing in Germany in his background narrative.
He states that the SKF ball bearing company's Swedish exports to Germany during WWII mitigated the effects of the 8th AAF bombing of German manufacturing in Schweinfurt. Along with high grade iron ore exports, the ball bearings may have allowed Sweden to remain neutral during the war.
Have I not seen some new numbers in the recent past that somehow validate this? His book doesn't have comprehensive footnotes so it's hard to tell how he would substantiate this fundamental claim. Even an evaluation of the numbers he uses in his argument show that Swedish and its U.S. subsidiary in Philidelphia (shipped through intermediate countries) shows they made up an insignificant % of the total required by the German war industry. [2 million bearings/month vs. 50,000/mo. from SKF-Philidelphia] To go on to say in a note on page 116 that the Schweinfurt raids were extremely costly to the 8th AAF and that SKF-Philidelphia made up the shortfall is preposterous to me.
Two well researched papers on the Swedish ball bearing export arrangements with Germany during WWII show that they supplied about 10% of their needs during the war through 1943.
I remember years ago reading the biography of Albert Speer. I realize some of it may have been self serving, similar to a de-Nazification tribunal report, but I noted his conclusions on the effects of strategic bombing by both the RAF and USAAF. He believed that the British failure to continue bombing the other related dams associated with the Mohne was a strategic mistake and left the Ruhr valley supplied with water and power. He was also puzzled by the cessation of US bombing of the ball bearing plants in Schweinfurt and Erkner in Apr, 1944. These targets were heavily defended especially in the Fall of '43. His opinion was that a continued bombing campaign in the Spring of '44 would have accomplished what the target planners had predicted and brought Germany's war materiel production to a virtual halt. We know that the 8th AAF shifted in Apr from oil and ball bearing targets to transportation targets in support of the Normandy invasion. He mentioned the exhausted stock piles and that imports could not make up the short fall.
Am I missing something?

 

[EwenS]

Regarding Operation Chastise, opinions about its success or otherwise, have varied from 1943 onwards. Maybe at best a tactical success from a brilliantly executed operation. But strategically?

As for not conducting further such raids a few points to consider.

1. The Upkeep mine was not well suited as a weapon for destroying all dams. It worked well enough on concrete gravity structures like the Mohne & Eder. It didn't work on the Sorpe (which IIRC Speer considered the most important to the Ruhr). The Sorpe dam had a concrete core with earth banks on each side.

The attack technique for the Sorpe nvolved the aircraft running along the length of the dam and releasing the Upkeep unspun, in the hope it would roll down the waterside slope. It was estimated that at least 5 accurately placed Upkeeps would have been required to weaken the structure sufficiently for the water to do its work.Only 2 aircraft survived to attack it.

The RAF returned to the Sorpe dam in Oct 1944 with 12,000lb Tallboys and still didn't breach it.

2. While not all the crews of 617 were, as suggested by the movie, hand picked and experienced, a significant effort went into training at low level. That meant withdrawal from regular operations.

3. The attack profiles for these targets were extremely difficult to fly. It is a tribute to the determination of the crews that carried out the mission, especially when several had to make multiple runs before dropping their bombs.

4 .The losses on Chastise were heavy - 8 of 19 crews dispatched. One of those survivors turned back, never having made it much beyond the Dutch coast due to flak damage.

5 .Immediately following Chastise, the Germans reinforced the defences of its dams. More flak was brought in, barrage balloons were added, and wooden booms placed at distances from dam faces in a bid to protect them.

6. With the element of surprise lost (One bomb from a crashed aircraft was captured intact when the self destruct device failed) further dams raids would have been even more hazardous to undertake.

 

[Grittis]

Regarding Operation Chastise, opinions about its success or otherwise, have varied from 1943 onwards. Maybe at best a tactical success from a brilliantly executed operation. But strategically?

As for not conducting further such raids a few points to consider.

1. The Upkeep mine was not well suited as a weapon for destroying all dams. It worked well enough on concrete gravity structures like the Mohne & Eder. It didn't work on the Sorpe (which IIRC Speer considered the most important to the Ruhr). The Sorpe dam had a concrete core with earth banks on each side.

The attack technique for the Sorpe nvolved the aircraft running along the length of the dam and releasing the Upkeep unspun, in the hope it would roll down the waterside slope. It was estimated that at least 5 accurately placed Upkeeps would have been required to weaken the structure sufficiently for the water to do its work.Only 2 aircraft survived to attack it.

The RAF returned to the Sorpe dam in Oct 1944 with 12,000lb Tallboys and still didn't breach it.

2. While not all the crews of 617 were, as suggested by the movie, hand picked and experienced, a significant effort went into training at low level. That meant withdrawal from regular operations.

3. The attack profiles for these targets were extremely difficult to fly. It is a tribute to the determination of the crews that carried out the mission, especially when several had to make multiple runs before dropping their bombs.

4 .The losses on Chastise were heavy - 8 of 19 crews dispatched. One of those survivors turned back, never having made it much beyond the Dutch coast due to flak damage.

5 .Immediately following Chastise, the Germans reinforced the defences of its dams. More flak was brought in, barrage balloons were added, and wooden booms placed at distances from dam faces in a bid to protect them.

6. With the element of surprise lost (One bomb from a crashed aircraft was captured intact when the self destruct device failed) further dams raids would have been even more hazardous to undertake.

EwenS, Without the effort on my part, I did not realize the complicated nature of these attacks. As most things in life or war, things are never as simple as the first blush would suggest.
Thank you for your detail.

 

[EwenS]

If you want to know more about Barnes Wallis' bombs and the various operations I would recommend books by Stephen Flowers:-

https://www.amazon.co.uk/Hell-Bomb-Barnes-Wallis-Helped-ebook/dp/B0CQ736BG1/ref=mp_s_a_1_15?crid=1JVJ2U84GBC1Y&dib=eyJ2IjoiMSJ9.ZIHTg0g3IoKNEfvwhTDzDhWcH_UU1_5OaV0KEmYzUbGGSjFztiguXwTy9e2xsBSmgxhmkQqz6VuTbskTU4YtDz1bsDYcebdT2vDr8B7U6M0o6OeTu3rdw6gu5dW34k1WhaDy8A4bMqijn5bAbs-VyPHC2XlKgKZJwdv9pULHpNcLCabXkXsyAhywBjAB2gLbcin1TMdRistXrqCrEyZ7RA.IHjbqn2LEha9j9YHtfoN29e2N6ubYEA_5ThZ3Pav9Bo&dib_tag=se&keywords=Stephen+flowers&qid=1722154353&sprefix=stephen+flowers%2Caps%2C195&sr=8-15

Later republished under this title

https://www.amazon.co.uk/Dam-Busters-Operational-History-Barnes-ebook/dp/B00EVC3956/ref=mp_s_a_1_17?crid=1JVJ2U84GBC1Y&dib=eyJ2IjoiMSJ9.ZIHTg0g3IoKNEfvwhTDzDhWcH_UU1_5OaV0KEmYzUbGGSjFztiguXwTy9e2xsBSmgxhmkQqz6VuTbskTU4YtDxy4rn8x2yR91kgfvvvLM2Lf_oIerxpkI5LOi1LuNfUwhaDy8A4bMqijn5bAbs-VyIXUCiPMR6QF9QmNczkd7CFoQ6C4RFEY9dTR_dBoQFzpcin1TMdRistXrqCrEyZ7RA.c8zTW2hW9scUr555L9PWPthCBz-7gHWR3TlkpSB9QiQ&dib_tag=se&keywords=Stephen+flowers&qid=1722154102&sprefix=stephen+flowers%2Caps%2C195&sr=8-17

 

[wuzak]

Regarding Operation Chastise, opinions about its success or otherwise, have varied from 1943 onwards. Maybe at best a tactical success from a brilliantly executed operation. But strategically?

Surely it was a strategic operation - a raid againt the enemy's means of production?

Compare the damage of Operation Chastise to other strategic raids - surely it was much greater than most?

Two dams were destroyed, which required the redeployment of some labour from the Atlantic Wall to repair.

A few factories were destroyed, several were damaged.

Agricultural land was rendered usely for a year or two.

Several bridges were destroyed.

1. The Upkeep mine was not well suited as a weapon for destroying all dams. It worked well enough on concrete gravity structures like the Mohne & Eder. It didn't work on the Sorpe (which IIRC Speer considered the most important to the Ruhr). The Sorpe dam had a concrete core with earth banks on each side.

True enough.

In planning they had identified several less important dams that would have been more susceptible to the bouncing bomb.

But would they be worth the effort/risk to attack?

2. While not all the crews of 617 were, as suggested by the movie, hand picked and experienced, a significant effort went into training at low level. That meant withdrawal from regular operations.

Certainly the crews were extensively trained, as much to do with low flying and navigation at night as anything else.

If other raids were to happen, they may have not been flown at low altitude, except for the actual attack run.

3. The attack profiles for these targets were extremely difficult to fly. It is a tribute to the determination of the crews that carried out the mission, especially when several had to make multiple runs before dropping their bombs.

Some more than others.

I think the Eder was harder than the Mohne.

Smaller dams may have been even more difficult.

4 .The losses on Chastise were heavy - 8 of 19 crews dispatched. One of those survivors turned back, never having made it much beyond the Dutch coast due to flak damage.

Yes, they were in terms of loss percentage, but not compared in pure numbers to other BC raids at the time.

One of the bombers lost the bomb when it hit a wave crossing the channel.

5 .Immediately following Chastise, the Germans reinforced the defences of its dams. More flak was brought in, barrage balloons were added, and wooden booms placed at distances from dam faces in a bid to protect them.

Which is diverting resources from other areas.

The British also upgraded the defences at important dams in Britain.

6. With the element of surprise lost (One bomb from a crashed aircraft was captured intact when the self destruct device failed) further dams raids would have been even more hazardous to undertake.

Yes, further raids would have been much more difficult.

And success was far from guranteed.

 

[wuzak]

Regarding ball bearings, the Germans had a small stockpile which allowed them to compensate for the loss of production for a short period.

Also, a number of ball bearing applications were redesigned to use plain bearings.

I have a vague memory of reading about a mission in teh wake of teh first Schweinfurt raid where a BOAC Mosquito carried diplomats to Sweden to negotiate the purchase of Sweden's ball bearing production. Anybody know of this?

 

[Geoffrey Sinclair]

Sweden required millions of tons of coal per year, that meant trading with Nazi controlled Europe. The British official history, 2 volumes, "The Economic Blockade" by W.N. Medlicott is a good overview of the situation.

I am reading "Vanishing Act" by Dan Hampton (2024) ....
He states that the SKF ball bearing company's Swedish exports to Germany during WWII mitigated the effects of the 8th AAF bombing of German manufacturing in Schweinfurt. Along with high grade iron ore exports, the ball bearings may have allowed Sweden to remain neutral during the war.
Have I not seen some new numbers in the recent past that somehow validate this? His book doesn't have comprehensive footnotes so it's hard to tell how he would substantiate this fundamental claim. Even an evaluation of the numbers he uses in his argument show that Swedish and its U.S. subsidiary in Philidelphia (shipped through intermediate countries) shows they made up an insignificant % of the total required by the German war industry. [2 million bearings/month vs. 50,000/mo. from SKF-Philidelphia] To go on to say in a note on page 116 that the Schweinfurt raids were extremely costly to the 8th AAF and that SKF-Philidelphia made up the shortfall is preposterous to me.
Two well researched papers on the Swedish ball bearing export arrangements with Germany during WWII show that they supplied about 10% of their needs during the war through 1943.

Anybody making claims of US goods to Nazi Germany needs to explain the route and length of voyage, for something rated as vital as bearings the US should have been keeping very tight control of distribution, so what was the country of destination according to the export documents? To around May 1940 the trade routes to Europe were largely open, plenty of friendly neutrals. For the next year comes via Japan/the USSR and Türkiye, after that only Türkiye. Sending bearings from Philadelphia to Germany in 1943/44 would be a gigantic failure on many levels, agreed it is preposterous.

I remember years ago reading the biography of Albert Speer. I realize some of it may have been self serving, similar to a de-Nazification tribunal report, but I noted his conclusions on the effects of strategic bombing by both the RAF and USAAF. He believed that the British failure to continue bombing the other related dams associated with the Mohne was a strategic mistake and left the Ruhr valley supplied with water and power. He was also puzzled by the cessation of US bombing of the ball bearing plants in Schweinfurt and Erkner in Apr, 1944. These targets were heavily defended especially in the Fall of '43. His opinion was that a continued bombing campaign in the Spring of '44 would have accomplished what the target planners had predicted and brought Germany's war materiel production to a virtual halt. We know that the 8th AAF shifted in Apr from oil and ball bearing targets to transportation targets in support of the Normandy invasion. He mentioned the exhausted stock piles and that imports could not make up the short fall.
Am I missing something?

Others have commented on the dams raid, apart from the technical troubles to really do the Ruhr dams alone, ignoring the rest of the German economy, would have required a bigger force and the understanding they would go out the next night to break any dams still standing, soon after that the defences would be too strong.

Speer can generally be relied upon for the economic facts, like many (auto)biographies the problems start with his idea of his actions. We know now destroying factory buildings was much easier than destroying the machinery inside, unless a fire took hold. We know after the 1943 raids the Germans discovered large stocks and ready substitutes, while a major advantage to Swedish supply was the ability to adjust orders to cover shortfalls. With ball bearings the obvious target came dispersal measures as well as better defences. Allied economic intelligence was weak, little solid information on losses in production. One reason the oil campaign was stepped up was the Luftwaffe Ultra messages reporting its fuel problems.

Schweinfurt was quite small making it a difficult target to locate at night, resulting in one of the few attempts at a night strike following a day one In addition the Battle of Berlin period saw Bomber Command gradually shut out of much of Germany unless willing to risk high losses. Similarly for the USAAF in the August to October 1943 period, it would take until the arrival of enough long range escorts before day raids could be resumed.

The following is from the Richard Davis spreadsheets, target class bearings or Schweinfurt as the location for the 8th Air Force and Bomber Command, note the losses even in the April 1944 raids, entries in date order.

AF	City	Date	Target Struck	Sighting	Atk	Lost	H.E.	I.B.	Frag	Total
8th	Schweinfurt/Kugelfisher	17-Aug-43	Bearings	Vis	54	9	25.0	88.0	-	113.0
8th	Schweinfurt/VKF 1	17-Aug-43	Bearings	Vis	78	4	145.0	40.0	-	185.0
8th	Schweinfurt/VKF 2	17-Aug-43	Bearings	Vis	51	23	127.2	-	-	127.2
8th	Paris/Hispano-Suiza	15-Sep-43	A/Ieng & Bear	Vis	78	3	229.0	-	-	229.0
8th	Schweinfurt/Kugelfisher	14-Oct-43	Bearings	Vis	81	10	165.7	-	-	165.7
8th	Schweinfurt/VKF 1	14-Oct-43	Bearings	Vis	61	35	63.0	74.1	-	137.1
8th	Schweinfurt/VKF 2	14-Oct-43	Bearings	Vis	86	15	166.5	13.5	-	180.0
8th	Paris	26-Nov-43​	Bearings	recalled	-	4	-	-	-	-
8th	Paris/Bois-Colombes	31-Dec-43	Bearings	Vis	57	1	164.3	-	-	164.3
8th	Paris/Ivry	31-Dec-43	Bearings	Vis	63	0	188.2	-	-	188.2
BC	Wuppertal/Elberfeld/Jaeger	30-Jan-44​	Bearings	OBOE (N)	9	0	9.0	-	-	9.0
BC	Wuppertal/Elberfeld/Jaeger	02-Feb-44​	Bearings	OBOE (N)	1	0	4.0	-	-	4.0
BC	Wuppertal/Elberfeld/Jaeger	04-Feb-44​	Bearings	OBOE (N)	1	0	1.2	-	-	1.2
BC	Wuppertal/Elberfeld/Jaeger	07-Feb-44​	Bearings	OBOE (N)	4	0	4.0	-	-	4.0
BC	Wuppertal/Elberfeld/Jaeger	08-Feb-44​	Bearings	OBOE (N)	3	0	2.9	-	-	2.9
BC	Wuppertal/Elberfeld/Jaeger	09-Feb-44​	Bearings	OBOE (N)	3	0	2.7	-	-	2.7
BC	Wuppertal/Elberfeld/Jaeger	11-Feb-44​	Bearings	OBOE (N)	2	0	2.0	-	-	2.0
BC	Wuppertal/Elberfeld/Jaeger	12-Feb-44​	Bearings	OBOE (N)	1	0	1.0	-	-	1.0
8th	Schweinfurt/Kugelfisher	24-Feb-44	Bearings	Vis	238	11	399.3	175.3	-	574.6
BC	Schweinfurt	24-Feb-44​	City	H2S (N)	662	33	1,372.8	1,160.8	-	2,533.6
8th	Stuttgart/VKF	25-Feb-44	Bearings	Vis	55	2	76.0	39.5	-	115.5
BC	Schweinfurt	25-Feb-44​	City	Vis (N)	5	0	2.2	0.7	-	2.9
8th	Berlin/Erkner VKF	08-Mar-44	Bearings	Vis	468	36	300.4	761.0	-	1,061.4
BC	St. Etienne/La Ricamarie	10-Mar-44​	Bearings	Vis (N)	16	0	64.0	14.2	-	78.2
8th	Schweinfurt/Kugelfisher	24-Mar-44	Bearings	H2X	60	0	51.5	78.8	-	130.3
8th	Schweinfurt/Kugelfisher	13-Apr-44	Bearings	Vis	153	14	202.5	138.7	-	341.2
BC	Schweinfurt	26-Apr-44​	City	Vis (N)	217	23	155.0	593.2	-	748.2
BC	Annency/Schmidt-Roost	09-May-44​	Bearings	Vis (N)	37	0	125.6	0.6	-	126.1
8th	Leipzig/DKF	29-Jun-44	Bearings	Vis	17	0	42.5	-	-	42.5
8th	Leipzig/DKF	07-Jul-44	Bearings	Vis	48	3	75.0	44.8	-	119.8
8th	Schweinfurt/VKF 1	19-Jul-44	Bearings	Vis	173	2	299.5	102.1	-	401.6
8th	Ebelsbach/Kugelfisher	19-Jul-44	Bearings	Vis	54	0	130.0	-	-	130.0
8th	Leipzig/DKF	20-Jul-44	Bearings	H2X/Vis	75	9	95.0	48.9	26.8	170.7
8th	Schweinfurt/VKF 1	21-Jul-44	Bearings	Vis	99	1	174.5	57.8	-	232.3
8th	Ebelsbach/Kugelfisher	21-Jul-44	Bearings	Vis	70	2	90.0	69.7	-	159.7
8th	Schweinfurt	09-Oct-44	I/A	H2X	329	0	811.2	4.7	-	815.9
BC	Schweinfurt	12-Oct-44​	City	OBOE (N)	2	0	1.8	-	-	1.8
BC	Schweinfurt	27-Oct-44​	City	Vis (N)	1	0	1.0	-	-	1.0
BC	Schweinfurt	31-Oct-44​	City	Vis/DR (N)	2	0	4.0	-	-	4.0
8th	Schweinfurt	22-Feb-45	RR/Br	Vis	1	0	3.0	-	-	3.0
8th	Schweinfurt	23-Feb-45	M/Y	Vis	12	0	35.5	-	-	35.5

8th Air force bomb tonnages on aircraft, oil and transport class targets versus total tonnage dropped for the month.

month	aircraft	oil	transport	Total
Jan-44​	2150.6​	980.4​	1902.1​	11679.2​
Feb-44​	3924.6​	0​	1835.9​	18339.4​
Mar-44​	3533.1​	128.5​	1179.5​	21046.6​
Apr-44​	6226.1​	0​	2281.4​	24931.3​
May-44​	3278.6​	2872.9​	10083.7​	36006.6​
Jun-44​	2070.5​	4966.1​	9795.3​	58271​

The January oil raid was at Ludwigshafen/I. G. Farben a combined oil and chemical target.

 

[Wavertree]

Surely it was a strategic operation - a raid againt the enemy's means of production?

Compare the damage of Operation Chastise to other strategic raids - surely it was much greater than most?

Two dams were destroyed, which required the redeployment of some labour from the Atlantic Wall to repair.

A few factories were destroyed, several were damaged.

Agricultural land was rendered usely for a year or two.

Several bridges were destroyed.




True enough.

In planning they had identified several less important dams that would have been more susceptible to the bouncing bomb.

But would they be worth the effort/risk to attack?




Certainly the crews were extensively trained, as much to do with low flying and navigation at night as anything else.

If other raids were to happen, they may have not been flown at low altitude, except for the actual attack run.




Some more than others.

I think the Eder was harder than the Mohne.

Smaller dams may have been even more difficult.




Yes, they were in terms of loss percentage, but not compared in pure numbers to other BC raids at the time.

One of the bombers lost the bomb when it hit a wave crossing the channel.




Which is diverting resources from other areas.

The British also upgraded the defences at important dams in Britain.




Yes, further raids would have been much more difficult.

And success was far from guranteed.

So the Germans had a bomb to work with - but did they have a bomber capable of carrying it?

 

[z42]

Also, a number of ball bearing applications were redesigned to use plain bearings.

I'm aware of the DB 605 switching to plain crankshaft bearings, from the roller bearings on the 601. Any other examples?

I have a vague memory of reading about a mission in teh wake of teh first Schweinfurt raid where a BOAC Mosquito carried diplomats to Sweden to negotiate the purchase of Sweden's ball bearing production. Anybody know of this?

I haven't heard of this. They used Mosquitoes to transport ball bearings they had purchased. Also Niels Bohr was exfiltrated in a Mosquito, so sounds plausible the same approach was used for other people as well.

 

[special ed]

Many years ago a magazine article about restoring a FW 190D to flying condition, in a shop in Minnesota as I remember, commented about restoring the Jumo.
The comment I remember was about the bearings are babbit and the rods and bearing blocks must be turned to fit available modern bearings after the babbit material was removed.
The restorer said although the Jumo's expected life was 25 hours the babbit bearings may not have lasted that long.

 

[Thumpalumpacus]

Middlebrook (The Schweinfurt-Regensburg Raid, p269) writes:

Regarding ball-bearings coming from America through the British blockade, after the fall of France I'd be pretty skeptical.

 

[Retattack]

USSBS monthly ball bearing production chart:

Reports. European War v.53-58.

 

[GreenKnight121]

So the Germans had a bomb to work with - but did they have a bomber capable of carrying it?

Not the point being made.

With an intact bomb, and with the spinning mechanism in the aircraft plus eye-witness accounts of the attacks, the Germans could determine exactly how further attacks on dams would be conducted, allowing them to determine which dams would most likely be attacked, from what direction, at what altitude, etc.

This would allow them to site defenses more effectively, and to develop and install effective counter-measures more quickly..

 

[EwenS]

And of course, with understanding of the concept, it allowed the Germans to develop their own bouncing bomb in 1943/44. Kurt. It came in several versions including versions that were rocket propelled. But more like the smaller Highball than the large Upkeep. But not spun like the British weapons.

Kurt Bouncing Bomb - Weapons and Warfare

The only known pictures of the SB 800 Kurt bouncing bomb. An FW 190 drops two bombs, which bounce over the sea for a considerable distance before sinking to

weaponsandwarfare.com

Project Kurt

I'm not sure where this would go so I'm posting here as a WW2 project. Some time ago I thought I'd read either on the web or in a book about a German Wallis-type bouncing bomb project and a modified Fw190 that carried two of them. I never found the source again and I thought I was imagining...

www.secretprojects.co.uk

 

[Engineman]

I'm aware of the DB 605 switching to plain crankshaft bearings, from the roller bearings on the 601. Any other examples?

Hi,
The roller bearings in the DB 600/601 engine "crankshaft" are only the forked connecting-rod big end bearings.
The crankshaft main bearings and the blade-rod bearings were always plain bearings. The change to all plain bearings on the DB 605 big ends was a planned improvement of the re-design. All these engines had many standard and special roller and ball bearings in the rear wheelcase, supercharger drive, the camshaft drives and the reduction gear, etc.

Eng

 

[Grittis]

Gentlemen, I have generated much more discussion of the dam busting than the ball bearing production question. Both were important strategic target categories for different reasons. I was not aware of the more complex problem of destroying such large features as were dams with different engineering features. I'm a Yank and am more concerned with the ball bearing question. It fits with the US Daylight Strategic Bombing doctrine. Yes, we can talk about the shortcomings of the mass production of the Norden bombsight. Yes, we can consider that by late 1943 the LeMay 'combat box' formations relied on a shotgun pattern based on Norden sights only in lead bombers. And yes, the Schweinfurt raids in late 1943 were extremely costly due to small attacking forces. But I also believe that in the 1st quarter of 1944, with larger attacking formations from the 8th AAF, escort fighters with new tactics, that serious damage was done to the German production of ball bearings. We have seen that the Swedish and foreign (insignificant) contribution to the total Ger. production was only about 10%. This was cut off in 1944. Yes, I realize that the Swedes shipped more ball bearing manufacturing machine tools and specialty steel in 1944, but the Germans expressed panic over their shortfall..... until the US changed tactics in Apr, 1944 and concentrated on transport in the lead up to Normandy. The Erkner 63mm bearings used in tank production were especially sensitive to disruption. This was expressed by Speer when he stated that he thought that a continued attack on German ball bearings would have paralyzed large sections of the German war production. And his complete surprize when the campaign was discontinued in Apr '44.
Many authors discount the Norden sight as a fraud and a propoganda campaign by the US government. No, you could not drop a bomb on a pickle barrel from 20,000 ft. But you could get closer to the barrel than any other piece of technology extant. Under real world conditions in N. Europe it performed inconsistantly. It worked great under ideal conditions at altitudes up to 10,000 ft. The British, however, had a much wider variance and so individual targets were abandoned early in the war. I believe Speer when he wrote that a sustained attack on oil (hydrogenation and coal gasefication), and ball bearings would have been a more fruitful use of the strategic bomber force.

 

[Thumpalumpacus]

Many authors discount the Norden sight as a fraud and a propoganda campaign by the US government. No, you could not drop a bomb on a pickle barrel from 20,000 ft. But you could get closer to the barrel than any other piece of technology extant. Under real world conditions in N. Europe it performed inconsistantly. It worked great under ideal conditions at altitudes up to 10,000 ft.

Yea, but when your bombers are at 25,000 ft, and the weather is crummy, it's not terribly useful.

American "precision bombing" is really a just-so story we tell ourselves. We just had better PR than Bomber Harris. Under real-world conditions, we too resorted to H2S/X, blind bombing, and secondary targets consisting of entire cities.

 

[Geoffrey Sinclair]

I also believe that in the 1st quarter of 1944, with larger attacking formations from the 8th AAF, escort fighters with new tactics, that serious damage was done to the German production of ball bearings.

January to July 1043 saw German Bearing production vary from 7,189 to 8,576. November 1943 to April 1944 saw a steady decline in output, halving. Meantime the dispersal can be seen by the "small firms" figures near doubling between early 1943 and early 1944 and then more than doubling again by mid 1944.

The August and October 1943 raids did little long term damage to output. While the fall from 8,082 in November 1943 to 6,866 in January 1944 happened without any new raids on German sites.

We have seen that the Swedish and foreign (insignificant) contribution to the total Ger. production was only about 10%. This was cut off in 1944.

Sweden was useful as it had an overall quota which meant the Germans could switch orders according to needs, while the cut off was in the second half of 1944, along with losses in France etc.

Yes, I realize that the Swedes shipped more ball bearing manufacturing machine tools and specialty steel in 1944, but the Germans expressed panic over their shortfall..... until the US changed tactics in Apr, 1944 and concentrated on transport in the lead up to Normandy.

Speer wrote his book as a sort of real time journal, so as various allied raids hit he reacts including ideas on possible future problems, which means you can generally find quotes for and against all aspects of the bombing raids on Germany.

The Erkner 63mm bearings used in tank production were especially sensitive to disruption. This was expressed by Speer when he stated that he thought that a continued attack on German ball bearings would have paralyzed large sections of the German war production. And his complete surprize when the campaign was discontinued in Apr '44.

Looking at the raid list the USAAF campaign dropped 5,823.5 short tons, the RAF 3,522.6 short tons. The USAAF had 9 raid days to end April 1944, as of 12 February bomb tonnage dropped by the USAAF was 1,489.5 tons, RAF 26.8, end February 2,064.1 to 2,560, end March 3,471.3 to 2,641.5, as of 9 May 3,712.5 to 3,515.8.

The USAAF 1943 raids dropped 1,489,5 tons, the February to April 1944 raids 2,223 tons and the June/July raids 1,256.6 tons, so why is April considered the cessation month? And why didn't the post D-Day raids at least partially fulfil the Speer worries?

8th AF % of bombs dropped on Germany November 1943 to October 1944, 83.90, 75.79, 70.96, 71.24, 69.56, 61.27, 55.21, 22.52 (June), 66.00, 49.18, 86.30, 99.96.

Many authors discount the Norden sight as a fraud and a propoganda campaign by the US government. No, you could not drop a bomb on a pickle barrel from 20,000 ft. But you could get closer to the barrel than any other piece of technology extant.

On the bombing range, when it came to raids the dust and smoke created by the first bombs created a form of smoke screen, reducing accuracy, it would have been better if the sight had the "false winds" ability, that is set it to apparently bomb a nearby landmark but actually hit the target.

Under real world conditions in N. Europe it performed inconsistantly. It worked great under ideal conditions at altitudes up to 10,000 ft.

At 10,000 feet the USSBS calculated an expected circular error of 570 feet for 3 bomber boxes, 765 feet for 15+ boxes, at 25,000 feet the numbers were 1,047 and 1,242 feet, at 29,000 feet 1,605 to 1,700 feet, note the closing of the difference, it was hard to hit an individual target with a lot of bombs. The heavy bombers could rarely bomb below 15,000 feet and certainly not key targets.

The USSBS reports the 9th Air Force bombers generally averaged 75 to 80% of bombs with 1,000 feet of the target. In the final 4 months of 1944 the 8th AF in good to fair visibility managed 30% with 1,000 feet.

The British, however, had a much wider variance and so individual targets were abandoned early in the war.

British day raids had targets, regular abandonment of individual targets at night took until the second half of 1941, the Butt Report, then returned in early 1944 with the bombings in France and then Germany

I believe Speer when he wrote that a sustained attack on oil (hydrogenation and coal gasefication), and ball bearings would have been a more fruitful use of the strategic bomber force.

As noted Speer wrote a lot of good quotes.

Raid reports, A good chance the first one is the combined damage from the and and night raids.

SCHWEINFURT, E.2606 - Min. of Arm. & War Prod, 24/25 FEBRUARY. This is the only source available and information refers to the ball-bearing works only. No details are available of any other results of the raid.

Estimated No. of Aircraft: 1100
Weight of Bombs dropped: 102681 kg. H.E. & incendiary
Weight of Bombs on work areas: 68330 kg. H.E. & incendiary
Floor area of works buildings destroyed: 79435 sq. metres.

SCHWEINFURT, 8a 2341 - LGK VII War Diary, E.2606 - Min. of Arm. & War Prod, 13 APRIL, (USAAF). A medium heavy attack was launched against Schweinfurt and Augsburg as well as a number of airfields. From 1313 to 1525 hours penetrations by strong formations with fighter escort took place between Longwy and Remagen. The more northerly forces attacked Schweinfurt and at 1436 hours a covering force was at Kaiserslautern and after covering the returning bombers left the LGK area between Luxemburg and Remagen.

At 1338 hours the stronger forces change course to SE in the Saarbruecken/Pirmasens area for their attack on Augsburg and airfields. (For detail, see under Augsburg and Airfields.)

Bombs dropped: 500 H.E., 2500 oil bombs.

Houses: 53 destroyed, 106 severely damaged, 282 medium to slight damage.

Fires: 40 major, 31 medium and 100 smaller fires.

Casualties: 13 dead, 37 injured.

The Rotenburger Metal Works are reported as destroyed, while Kugelfischer, VKF and Duetsche Gelatine suffered severe and Fichtel & Sachs medium damage.

At Fichel & Sachs 756 sq. metres of floor space were destroyed by 67 incendiary bombs and Kugelfischer, Georg Schaefer & Co. suffered damage from 1800 kg of mines, 29000 kg of H.E. and 3500 kg of incendiary bombs which destroyed 17% (= 42500 sq. metres) of floor space.

In addition, 500 H.E., 270 fragmentation and 606 oil bombs were dropped on the 80 localities, destroying 77 houses and damaging 203, killing 114 and injuring 130.

SCHWEINFURT, 8a 2341 - LGK VII War Diary, E.2606 - Min. of Arm. & War Prod, 26/27 APRIL. Between 0054 and 0143 hours a force estimated at 400 to 500 aircraft entered the area and steered an E course between Mannheim and Stuttgart and later a N course to Schweinfurt.

Bombs dropped: 6 mines, 300 H.E., 5000 phosphorous bombs, 20000 incendiary bombs.

Houses: 122 destroyed, 120 severely damaged, 64 medium damage, 335 slightly damaged.

Casualties: 5 dead, 45 injured.

The ball-bearing works sustained fairly heavy damage. No. 1 Works of the United Ball-bearing Co. were obliged to reduce their production for some days. At Fichtel & Sachs the gas generator plant was put out of action for some time as a result of fire and the Star Co. suffered very severe damage, resulting in a 100% drop for some time. The Rotenburger Metal Works also suffered a 100% drop for about a fortnight as a result of severe damage by H.E. bombs.

In the Armaments Ministry document the weight of bombs dropped on Star Kugelhalter Gesellschaft, Kugellager Fichtel & Sach and Kugelfischer, Georg Schaefer & Co. is given as about 22000 kg of mines, H.E. and incendiary bombs. The greatest weight fell on Kugelfischer, Georg Schaefer & Co. but 68% (16625 sq metres) of the works area of the Star Kugelhalter Gesellschaft was destroyed.

SCHWEINFURT, 8a 2341 - LGK VII War Diary, E.2606 - Min. of Arm. & War Prod, 19 JULY, (USAAF). About 200 - 250 bombers with fighter escort penetrated on an easterly course from 0810 to 0903 between Schneeifel and Ahrweiler.

Bombs dropped: 1000 H.E., 1200 oil bombs, 5000 incendiary bombs.

Houses: 123 were destroyed and 200 sustained medium to slight damage.

Casualties: 5 dead, 30 injured and 49 missing.

Fichtel & Sachs ball-bearing works sustained damage causing 100% loss of production for the time being, and Star Ball-bearing works suffered medium damage. The telephone and teleprinter service were put out of action. The Adolf-Hitler Barracks also suffered damage by H.E.

According to Document E. 2606, 39 H.E. and 10 incendiary bombs fell on Fichtel & Sach, destroying 9416 sq. m. of floor space of the works. At Kugelfischer, Georg Schaefer & Co 18000 kg of H.E. and 1900 kg of incendiary bombs were dropped destroying 18000 sq. m. (= 8%) of the total works complex.

SCHWEINFURT, E. 970 - LGK XIV, 9 OCTOBER, (USAAF). About 350 - 400 aircraft carried a raid between 1432 and 1515 hours, when the main target was the industrial area of the town.

Bombs dropped: 1500 - 2000 H.E. as well as incendiary bombs.

Fires: 1 major and 12 smaller fires.

Casualties: 22 dead, 14 unrecovered.

Kugel-Fischer was hit by 9 H.E. and some damage was caused. No.2 works of VKS suffered severely in the press shop, lathe department, machine tool shop etc. A quantity of oil was burnt. The Star Ball-bearing works suffered from H.E. and the main water supply was destroyed. Considerable damage was also caused to the electricity supplies.

The Central Station was hit by 58 H.E. and 5 duds, causing 12 lines to be put out of action. A quantity of H.E. bombs was alto dropped on targets in the neighbourhood of Schweinfurt causing material damage and a number of fatal casualties.