Bomber offensive vs. Gemany: you are in charge

Between Dunkirk and Brest there were sixty-six radar stations. To attack them all, even with the formidable air strength available to the Allies, was hardly possible and it was therefore decided to combine assault by air with radio counter-measures.

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My take on it is that they didn't attack the radar stations until just before D Day because they could be replaced too easily. According to Wiki, the Germans produced more than 1,000 Freya sets and more than 4,000 Würzburgs.

The 1000 Freyas (early warning type) means that it took 3 days to produce 2 sets, give or take. IMO that number can be hardly enough to replace the destroyed ones, once the dedicated campaign starts. Without Freyas, Wurzburgs (fire control type) lack the early warning, same thing for fighter units. With heavy bombers dropping heavy bombs, trained radar crews are also in jeopardy. The radar aerials are far better targets for day attacks than tanks or guns.
The allies were in much better position to replace their bombers than Germans their radars, ratio being perhaps 10:1.

If you took out even a couple of Freyas you would cause grief I imagine there were only so many teams with skills to survey and place units , it not just a matter of plopping them down on a piece of dirt . You'd need a well prepared surface with lots of surveying a nice level pad not even including commuications to what ever was central command . I'm sure they required APU's etc , testing labs etc . IMHO it 2was a missed opportunity

At the time the RAF and USAAF decided jamming and spoofing was the main way to combat German radar. They couldn't have committed to that effort without at least considering simply bombing German radar sites. I think it's difficult for us to second guess them with far less information than they had available.

There is no need for second guesses, since both Brits Yanks knew, rather early in the war, that radars are the key part for any air force defending something. Particularly Brits had the 1st hand experience from BoB.
A spoofed and jammed radar needs such a treatment for every aerial attack vs. German held Europe, maybe 3 times within 24 hours (one for night bombers, other for USAAF, 3rd for RAF's Typhoons Spits)? A destroyed radar does not. Since the Ultra was reading many of the German messages, the big, radiating radar aerials were not that secret.

Both Freya's and Wurzburgs could be bunkered and toughened against attackers. Freya's were bunkered by building them within sandbagged brick walls so that only the antena protruded or they could be recessed. This protected the opperators and the electronics. They could be and often were defended by light FLAK and it could be guaranteed that they would be able to take some attackers with them. A direct diving attack or a direct hit with bombs would be required. The attacker would need to get close.

The small Wurzburg-D were a little harder to protect however the giant Wurzburg Riesse were quite difficult but even these could be.


Left Freya (one of many types of Freya)
right Wurzburg-D with conical scanning 0.3 degree accuracy (0.5 in horizonal plane near ground) range accuracy 25m capable of 45 knautical miles range both search and FLAK direction.

Flakleit-G was an tunable 81cm system derived from seatakt. It could search for both sea and aerial targets, could height find and direct blind fire against both sea and land targets. As can be seen it is well protected. Several hundred built for the Germany navy tasked with guarding harbour areas. I is said to have been the most accurate German radar when directing against aircraft: better than 0.1 degrees.

The naval gun fire directing radar Scheer also used thye same attena as Wurzburg Riesse.


The radars on with on top of the tall towers are Kurmark and Kurplatz by the Lorentz company, a good radar produced only in the dozens of each type due to some degree of shortsighteness.

The Telefiunken Wurzburg-D could be mounted atop this Lorentz designed tower so that the controls. crew, electronics could be safely bunkered. The radar was known as FuSE 63 Mainz. In this guise it came with improved circuitry to increase tracking accuracy. About 50 produced and in service late 41 or early 42.

An even more advanced version was FuSE 64 Mannheim with more power, more accuracy and automatic range gate tracking.

The larger Wurzburg Riesse was in fact an expedient solution to directing FLAK, however the grearter range it provided an excuse to misuse it to direct night fighters.

Ansbach was a Wurzburg type radar that used the electronics of the 3m Wurzburg (same as 7.4m Wurzburg-Riesse) but a 5m antena that was remote controlled so aid concealment and bunkering. The next generation of German radars was to opperate at 25cm using technology developed independant of the magnetron. The program was suspended due to too few engineers after a few prototypes were built by Lorentz and Telefunken in about 1942. The program was resurrected when the British Magnetron was recovered.

If you take a look at the excerpts Hop kindly provided, the determined campaign against the radar sites was quite successful, despite the measures of protection.

Some might be surprised to realize that the site of the radar is very important , obviously on some higher point without obstuctions , it requires a fair amount of surveying , then all the communications required its no small task and would require a lot of skill sets . It just isn't plop it down and plug it in especially for "heavy radar" . Just imagine the amount of land lines specific to the unit a SAGE type enviroment can't have those pesky resistance chopping down telephone poles.

Juha said:

I still wonder why Germans didn't use that claimed ferry range, at least not often. In all 109 pilot memoirs I can recall, when they ferrier 109s to the east they did it by rather short stages. Same to Finns when they ferried 109s to Finland. And when 11./JG 2 with its 109G-1s were transferred from Normandy to Tunisia via Sicily in early Nov 42, it didn't flew to Southern France and then across the Med to Sicily, not even via Sardinia to Sicily. No, it first went to Mannheim and even that was impossible without a refilling stop at Rheims. From Mannheim to München, then to Treviso-Jesi-Bari-Reggio di Calabria-Trapani-Comiso-Pantelleria. It departed on 4 Nov 42 and arrived to Sicily on 8 Nov. To me that didn't show specially good ferry range.

Now Mk VIIs flew a few long range escort missions in ETO, the longest I'm aware took 3h 50min and Mk VIIIs flew long range escort missions in Pacific, the longest I'm aware was 4h 30min long, so it had some practical use.

Juha

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The range of an Me 109G was as follows (approximate)
1 High speed cruise (about 320 knots) 390 miles
2 High speed cruise with 66 gallon drop tank about 600 miles.
3 Economic cruise with drop tank about 1000 miles.

The range without drop tanks is actually slightly better than the Spitfire IX at similar speeds. The Germans only seemed to use single 66 gallon drop tanks. Recon Me 109's could carry 3 of these.

Long single hop ferry flights conducted at slow speed were probably dangerous from the point of interception and possibly dangerous from the point of view of navigation errors. A 5 hour flight would be little fun and most fatiquing.

pbfoot said:

Some might be surprised to realize that the site of the radar is very important , obviously on some higher point without obstuctions , it requires a fair amount of surveying , then all the communications required its no small task and would require a lot of skill sets . It just isn't plop it down and plug it in especially for "heavy radar" . Just imagine the amount of land lines specific to the unit a SAGE type enviroment can't have those pesky resistance chopping down telephone poles.

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The best site for non microwave radar is actually in a shallow bowl of land. The 'perimeter' of the bowl creates some clutter but all clutter is beyond that is blocked by the perimeter of the bowl.

German radars could use decimetric (50cm) links to provide remote PPI displays and communication links, they were in fact widely used.

Partisan attacks on radars would be a very poor use of their lives. They need to stick to reconaisance and at most blocking trains. Cutting telephone lines was a strategy to force more traffic onto the air and then be vulnerable to code breaking, however I believe the 50cm links were too directional for that.

Siegfried said:

The best site for non microwave radar is actually in a shallow bowl of land. The 'perimter' of the bowl creates some clutter but all clutter is beyond that is blocked by the perimter of the bowl.

German radars could use decimetric (50cm) links to provide remote PPI displays and communication links, they were in fact widely used.

Partisan attacks on radars would be a very poor use of their lives. They need to stick to reconaisance and at most blocking trains. Cutting telephone lines was a strategy to force more traffic onto the air and then be vulnerable to code breaking, however I believe the 50cm links were too directional for that.

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Should let NORAD in on that secret for all these years theve been putting heavy radar on top of hills , maybe though they may not have the brains of the germans . Have you ever worked or better yet seen a radar. I ve seen and worked on several types mind you not heavy just ASR and PAR but for light radar could pick up a target at 200 miles , or in the case of PAR watch a guy pedal a bicycle at a few miles
and as for remotre PPI and comm links what did they use if not land lines ,

Siegfried said:

The range of an Me 109G was as follows (approximate)
1 High speed cruise (about 320 knots) 390 miles
2 High speed cruise with 66 gallon drop tank about 600 miles.
3 Economic cruise with drop tank about 1000 miles.

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The problem with economic cruise speed was that according to Finns cruising at speeds of 450km/h TAS or slower fouled the plugs and carbon monoxide seeped into the cockpit. Or more accurately "flooding of carbon monoxide into the cockpit." So not very practical for longer periods.

Siegfried said:

The range without drop tanks is actually slightly better than the Spitfire IX at similar speeds. The Germans only seemed to use single 66 gallon drop tanks. Recon Me 109's could carry 3 of these.

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Now most of us agree that standard Spit Mk IX was rather short-legged fighter. So to have a slightly longer range than it wasn't very big achivement. And did LW use recon 109s with 3 300l drop tanks? I'm aware only that normal recon 109Gs could carry one 300l drop tank and the special LR recon 109Gs could carry and carried 2 300l DTs, one under each wing.

Siegfried said:

Long single hop ferry flights conducted at slow speed were probably dangerous from the point of interception and possibly dangerous from the point of view of navigation errors. A 5 hour flight would be little fun and most fatiquing.

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Now the ferry flights to Finland and to southern part of the Eastern Front were flown over Axis controlled areas and VVS didn't usually conduct LR fighter sweeps in 43, so interception risk was minimal there, and IMHO not very high in early Nov 42 N of Sicily. And Mannheim is a bit under 500km from Poix, but even that distance meant a refuelling stop and Rheims for 11./JG 2. So it seems that at least 11./JG 2 didn't use the economic cruise. And landings and t/os were/are the most dangerous parts of flying, difficult to see why maximize their number.

Juha

pbfoot said:

Should let NORAD in on that secret for all these years theve been putting heavy radar on top of hills , maybe though they may not have the brains of the germans .

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I doubt they were quite up there with Kunhold, von Wilsen. Refinement is easy after others have done the inventing.

pbfoot said:

Should let NORAD in on that secret for all these years theve been putting heavy radar on top of hills (SNIP) I ve seen and worked on several types mind you not heavy just ASR and PAR but for light radar could pick up a target at 200 miles , or in the case of PAR watch a guy pedal a bicycle at a few miles
and as for remotre PPI and comm links what did they use if not land lines ,

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Note, I did specify "non microwave radar". With a narrow beam microwave radars, or those with excetionally large antena can avoid ground clutter by simply stearing clear of it though the clutter will still appear when the beam is seeking low flying targets.

Pulse Doppler helps as well.

The need to site metric radars in slight depressions was eventually learned by all sides; the Germans probably among the first as they were using mobile Freya's in inland areas ahead of others.

stona said:

Way back in this thread I made the point that low penetration light,specialised raids like Amiens and Copenhagen are utterly irrelevant to the conduct of a bombing campaign designrd to destroy and dislocate an enemies production capability.

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Those raids had very specific objectives, nothing to do with the bombing campaign at large.

However, those raids demonstrated accuracy well beyond the normal operations of Bomber Command and the 8th AF. Look at Schweinfurt - 80 direct hits on the target buildings. With 100% accuracy that would require 20 Mosquitos. But since we can't count on 100% accuracy we can use 40 Mosquitos - comapred to 300+ B-17s. It would be a more efficient use of resources.

stona said:

As for the dams raid,delivering a few mines to destroy two dams for a minimum return at an enormous cost was,sadly, a propaganda victory and nothing more.That's why the photo reconnaissance photos of one of the destroyed dams (Mohne?) appeared in the British press so rapidly. No air force could sustain that level of loss on regular operations.

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Again a small raid, not sure that the cost could be described as "enormous".

As for the returns, that is disputed by many, but here are some effects of the Dams raids (from Stephen Flower, A Hell of a Bomb).

Eleven factories were destroyed, 114 damaged from the Möhne dam alone. Some rail lines were cut by flooding or damage to bridges. Many other bridges were swept away. Very importantly large areas of agricultural land were rendered useless for food production, and some stocks of food were lost. That land would not be arable for many months.

Another effect of the dams raid was that all the dams in Germany would now be defended heavily. Taking resources away from other areas. 20,000+ workers were moved into the area for cleanup and repair efforts. Many of these had been working on the atlantic wall. According to Speer up to 1/3 of the workers on the Atlantic wall left becuase they feared they would be sent to Germany. This required a policy change.

By early 1944 the Möhne dam was near full capacity, but due to the fears of another attack the level was reduced so that the capacity was half, and the water pressure (affects the power that can be generated) reduced.

The Kriegsmarine developed mines that would explode if low flying aircraft were to fly over. 5 rows of these were installed in the lake. Smake screens were installed, extra towers erected, more torpedo netting and deflection booms added. Chain mail was suspended on the air side of the Möhne to protect against rocket propelled bombs.

Some 2500 men were involved in the defences at the Möhne Dam, and saw little action in th remaining period of the war.

The Eder Dam repairs were not completed until 1947, so it could not reach full capacity until then.

The Germans also used a captured Upkeep to develop their own bomb, and even a smaller rocket propelled version that coud be carried by an Fw190 - none of which were ever used.

Some damage - like that to generating facilities - was repaired or compensated for quickly.

Overall I would say the direct damage caused may not have had great effect, but the flow on effects were significant.

Besides, in what other raid of 19 bombers were 11 factories destroyed and 114 damaged?

Well said, Wuzak.

I wonder if any of the air forces was using clockworks in part of their bombs, randomly timed, in order to make repairs of a bombed site a risky business?

tomo pauk said:

Well said, Wuzak.

I wonder if any of the air forces was using clockworks in part of their bombs, randomly timed, in order to make repairs of a bombed site a risky business?

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I believe BC sometimes used long delay fuses in order to do just that.

It may have been a common practice by many countries.

Those nineteen bombers (which left the UK) did not achieve the level of dislocation envisaged by the planners,this was later blamed on the failiure to destroy the Sorpe dam,something probably impossible with the "Upkeep" mine in any case. The British over estimation of the damage caused led to another familiar failing,that of not following up with further conventional raids to prevent the rapid repair to the dams and associated infrastructure.
You actually failed to mention the biggest problem caused to German production (according to the Germans) which was the loss of hydro electric power from the generating stations associated with the dams and even this was partially restored in a couple of weeks.
The RAF lost EIGHT of the NINETEEN highly trained crews on the raid,a completely unsustainable percentage and a poor return on a magnificent and heroic
investment.
Actually lowering the water level in the lake behind a dam does not automatically reduce the capacity of the generating station downstream. The Germans were back to full power from the dams by the end of June about six weeks after the raid.
Cheers
Steve

Every AF had bomb fuzes with delays of up to almost a week, with anti-disturbance features that would set the bomb off if anyone moved the bomb, or attempted to remove the fuze.

Did RAF ever tried to use the delayed-action (clockwork equipped) bombs to mark the target for the subsequent raid? Say, 10 bombs to detonate 3 nights later, flames appropriately colored?