The Battle of the Radar Nets over Western Europe: 1944-1945

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Things were a little different for Bomber Command night operations. Navigators of individual aircraft were up to their own capabilities to navigate to the target and back. They did not formate on other aircraft. Critical and emphasised at all times, was the need to keep the Bomber Stream compact, and crews followed timing to turning points at specific speeds and height bands. GEE was the primary navigational aid and once outside of GEE range (and once jammed by the Germans) the navigator relied on fixes with towns along the way to supplement and correct his dead reckoning navigation.

Jim
 
...further to the above, I have the chart and log of my father's navigator for the operation to Chemnitz. A stunning document that puts me right in the aircraft. Far more thrilling to delve into than a video game. I've spent hours pouring over it.

Jim
 
What was most on my mind when I posted this was the effect that allied radar - once deployed on the continent - affected German operations. As the allies moved forward, even some of the homeland defense bases in Germany were covered by allied radar. When Allied fighter strength started crossing over from air superiority to air supremacy, it had to make everyday operations difficult.
 
I probably should have posted this earlier in the thread but better later than never. At the end of hostilities in Europe, the entire German Raid Reporting and Control System in Denmark had been captured intact, together with associated personnel and operators who staffed the System. Very quickly the Air Ministry ordered Bomber Command to conduct an investigation and a series of exercises to test the German System as well as the effectiveness of their own measures. This was undertaken promptly at the end June-1st week of July 1945 and was titled: "Exercise Post Mortem"

The complete report is available at the National Archives, Kew:

"Report on an Investigation of a Portion of the German Raid Reporting and Control System"
AIR 20/1723 Exercise "Post Mortem": investigation of a part of the German raid reporting and control... | The National Archives
AIR 20/1723 Exercise "Post Mortem": investigation of a part of the German raid reporting and control... | The National Archives

Those interested in obtaining these files can PM me with their email address and I will WeTransfer the images. The download is 369 mbytes and 129 JPG files. Note that Alfred Price apparently refers to this exercise in one of his books. I do not have that book so cannot comment on it. However, following my general practice, I believe review of the "primary source material" is always the best practice of even the amateur historian.

Edit: Alfred Price's book is called "Instruments of Darkness"

NOTE: This was a HUGE undertaking, involving 200 heavy bombers and all told over 331 aircraft on some exercises. Initially, I had intended to provide a high level summary of this, however, to remove any errors in interpretation on my part, I will post a series of screen captures below outlining the major conclusions:




Jim
 

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JD,

From an adversarial GCI perspective things weren't that different between day and night when painting the picture. Painting the picture means verbally describing what the adversary is doing, where they are doing it, and which way they are going. Regardless of whether it's a mass daytime visual formation or each aircraft is navigating individually in a stream made as compact as possible at night, it's something that needs to be attacked and delt with.

A compact stream at night, versus a large visual formation in daytime operations, would still be of some length, height, speed, location, and heading in some direction. That is the information that needs to be passed for the fighters / predators to get to the prey. And those descriptors are anchored off some common point or points, either a geographic reference or when doing close control the attacking aircraft itself.

Cheers,
Biff
 
As I understand it there, was little difference between a night time RAF raid and a day time USAAF raid in terms of numbers of bombers passing over the target in a given time, The night time bomber stream and the day time succession of box formations resulted in almost the same concentration, if both were viewed in daylight they would look much different though.
 
I agree completely, and both would be attacked differently (swarms of SE fighters day time (mass of firepower), small groups / singles of mostly TE fighters at night). However, how you describe the formations will be almost the same regardless of day or night (which is what I was driving at).
 

Perhaps I'm missing something here but I'm not sure I agree. Even the RAF daylight formations employed September 1944-April 1945, were not the same as those used by the USAAF. The USAAF used a very compact formation. The RAF Gaggle was much looser. The similarity by day was in the fact that navigation was by a single, lead crew, albeit with possible feedback from other designated crews incase there was an error in navigation (which happened on at least one occasion). The reason the RAF Gaggle was different, was the crews simply didn't have the experience in formation flying that was ingrained into the USAAF.

Dad did 11 daylight operations and 20 night operations. The average rate-of-loss on the daylight operations was 0.47%. This compares to a loss 3.42% or roughly 3.7 times higher. Most of the losses daylight operations were due to flak, the RAF and USAAF fighter cover driving off the Luftwaffe. Most of the losses at night were due to the Nachtjagd.

In terms of concentration of aircraft over the target, I think you would need to look at a frequency distribution of bombing times over the target and compare with those of the USAAF for similar sizes of attacking formations. I know the individual RAF bombing times are available in the ORB's, I don't know if the same is available for the USAAF. Based on their tactics that involved all aircraft bombing at the same time as the "Lead" aircraft, I'll betcha the USAAF bombed over a much shorter duration of time.

Jim
 
Jim,

I agree with everything you just wrote. However, from a scope dopes perspective (GCI controllers) and the comm they would use it wouldn't make any difference. The ability to count numbers in a group did not hit a quality point until the late 90s. And estimating a group size (front to back and or side to side) would be fairly easy to difficult depending on your type of scope and proficiency at interpreting it.

Cheers,
Biff
 
Agreed. The German controllers often overestimated the size of a spoof force and underestimated the size of a Main Force. I believe Window had a lot to do with that.

Jim
 
True, for each "box" formation, but the separation of the boxes evened things up.
 

Well, I've compiled the bombing time and altitude for 106, 408, and 433 Squadrons (when that info was listed).

On occasion, an aircraft reached the target only to not bomb due to either a mechanical malfunction, enemy action, or not being able to see the aiming point/target indicators. There were several missions on which all the aircraft did not bomb, due to the aiming point/target indicators being fully obscured by cloud and the master bomber calling off the attack.
 
I've only gone through this carefully on Dad's op to bomb the U-Boat pens, Bergen, October 4, 1944. 82% of the crews for the 5 squadrons I looked at (419, 428, 431, 432 and 434) bombed in a 3 minute stretch from 0929-0932 hours. I think that tight distribution is pretty unusual. Considerably broader distribution for other raids, I believe. Those were ANM SAP bombs, BTW. The aircraft was KB.762, "J" Jig On the op on the 9th of October to Bochum, they bombed 6 minutes early and Dad's navigator told me he caught a rocket from the Navigation leader for his transgression.
Jim
 
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This is the frequency distribution for Bergen in 1/10 minute increments. There are major peaks at 0929, 0930 and 0931 and secondary peaks at the 1/2 minute marks as well. This is almost certainly a "recording" issue with the bomb aimer or navigators rounding up to the nearest full minute or half minute.

 

My impression is that bombing times in general became more concentrated as the war went on, which comports with the changes made to condense the time taken for a raid as tactics evolved.

In the post-mission descriptions in some ORBs, there were occasions on which a bomber arrived at the target and then had to perform several orbits of the target, waiting for target indicators on which to bomb. In some cases they would finally bomb, and in other cases the crew gave up as nothing was visible and they returned to base.

(419 Squadron is on my list to go through eventually.)
 
Exercise post mortem Air 20/6282, also from AIR 14/3368. Dates in 1945. Originally planned as 14 exercises, with around 200 heavies on numbers 1 to 5, 9 and 10. While 11 and 12 Mosquito bomber only force. Exercises 2 to 10 to use radar restrictions as per most recent operations in target area.

100 Group support,
1 to 3, 11 and 12 none.
4, Mandrel screen, 20 aircraft
5, as above plus 24 Window, 6 Mandrel and 4 Piperack/Jostle/Carpet aircraft dispersed within bomber force.
6, 24 Window aircraft
7, 20 Mandrel screen plus 24 Window aircraft.
8, as for exercise 7 plus with Window force, 4 Piperack/Jostle/Carpet, 4 ABC/Jostle/Carpet, 6 Mandrel aircraft
9, 20 Mandrel screen plus 45 Window/Jammers.
10, 20 Mandrel screen plus 2 Window forces totalling 48 aircraft.
13, 22 Window aircraft accompanied by 6 Mandrel aircraft in pairs at 15 mile intervals.
14, 28 Window aircraft including 6 Piperack jammers.

13 and 14 optional, if time permits and are considered necessary.

13 scenarios
1, 1 force of heavies, no window
2, 2 forces of heavies, own window
3, 1 force of heavies, low altitude
4, 2 forces of heavies, own window, Mandrel screen
5, 2 forces of heavies, own window, Mandrel screen, plus Mandrel aircraft in force.
6, 2 Window forces only
7, 2 Window forces plus Mandrel screen
8, 1 communications jamming force flying as if they would be using Window
9, 1 Piperack jamming force flying as if they would be using Window
10, Grand finale, including Window force breaking from main force, all jamming employed
11, Low flying Window forces, simulating an airborne landing.
12, 20 high flying Mosquito, "in fair dilution"
13, as for 12 but at low altitude.

39 German radar stations, (Drch Freya, Elephant, Freya, Jagdschloss, Mamut, Wassermann, Wurzburg), 18 in Star Area, 13 in Ringelnatter Area and 8 in Faun Area, plus 3 first class and 7 second class operations rooms.

Actual operations,
25 June, Post Mortem Exercise 1, Flensburg, 134 Lancasters from 1 Group, 67 from 3 Group, 20 from 8 Group, total 221. Route A Flying 17/20,000 feet, H2S on from start.

25 June, Post Mortem Exercise 3, Flensburg, 126 Lancasters from 1 Group, 64 from 3 Group, 20 from 8 Group, total 210, 1 Lancaster lost, Route B Flying 17/20,000 feet, using Window

29 June, Post Mortem Exercise 2, Flensburg, 139 Lancasters from 1 Group, 65 from 3 Group, 32 from 8 Group, total 234. Route A start climb from 2/3,000 feet to 17/20,000 feet at 6E

29 June, Post Mortem Exercise 6, Flensburg, 12 Halifax and 12 Fortress from 100 Group, total 24. Route B. Window force at 18,000 feet simulating 10 mile wide, 6.5 mile deep main force raid, no jamming.

1 July, Post Mortem Exercise 4, 134 Lancasters from 1 Group, 60 from 3 Group, 24 from 8 Group, 22 Halifax from 100 Group, total 238, 1 Lancaster crashed in Britain. Route B. Main force to use Window from Mandrel screen onwards.

1 July, Post Mortem Exercise 11, 35 Mosquito from 8 Group. Route A, Mosquito without countermeasure support at 25,000 feet.

1 July, Post Mortem Exercise 7, 12 Halifax and 12 Fortress from 100 Group, total 24. Route B. As per exercise 6 but with Mandrel screen.

2 July, Post Mortem Exercise 12, 36 Mosquito from 8 Group. Route B, as per exercise 11 but at 2/3,000 feet.

3 July, Post Mortem Exercise 9, 137 Lancasters from 1 Group, 65 from 3 Group, 30 from 8 Group, 25 Halifax (Mandrel), 25 Halifax (Window), 20 Fortress (Window) from 100 Group, total 300 Route A. Window force to push through Mandrel screen and fan out just ahead of main force which will be flying at 17/20,000 feet.

4 July, Post Mortem Exercise 5, 135 Lancasters from 1 Group, 65 from 3 Group, 30 from 8 Group, total 230 plus RCM support. Route B, Repeat of exercise 4, with all jamming to be used plus Window diversion force to break away fom main force.

4 July, Post Mortem Exercise 5 and 8, 27 Halifax, 12 Fortress, 1 Halifax from 100 Group, total 60. Exercise 8, Route B, Window force at 18,000 feet plus jamming simulating main force used in exercise 5.

5 July, Post Mortem Exercise 10, 132 Lancasters from 1 Group, 84 from 3 Group, 30 from 8 Group, 30 Mosquito from 8 Group, 60 Halifax and 22 Fortress from 100 Group, total 342. Route C. Two Window forces plus main force and full jamming, Window forces to diverge to create apparent 3 prong attack, no one on ground will know in advance which is the actual main force.
 
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