1944: Flak Alone Blasts the Allies out of the Sky

[LWD]

Two very interesting pieces of info which I´ve just read:
....
From "Das Deutche Reich und der Zweite Weltkrieg", vol. 7, p. 284, my translation:

"The Germans ... invented the socalled dubbel fuse, a combined time and impact fuse..... With the dubbel fuse the heavy flak shot down 13 bombers each for 370 shells, whereas until then 3500 to 4000 heavy shells and 5000 - 6500 light flak shells were needed per shoot down."

And..

"The Rheinmetall electrical proximity fuse which was ready at the end of the war didn´t become operational... An American post war study revealed that the American bomber losses would have been 3.4 times as high as they were ...

These numbers make it look like the dubbel fuse was more effective than the proximaty fuse?????

[JonS]

well, duh. The dubbel was German, so of course it was better.

[T. A. Gardner]

A couple of questions here:

1. What do the Germans do when they are unable to visually range on the bombers (the usual case) and their radar systems are jammed or seriously degraded by jamming? Go to box barrages? Guess the altitude and fire on those settings?

2.. If the Germans do introduce a proximity fuze using radio location (as the Allied one did) what is to stop the Allies from jamming that too? The US did carry out tests at Wright Army Airfield in Ohio proving that jamming of proximity fuzes was possible.

3. How does adding and impact fuze to a time fuze achieve "ten times the results?" Since direct hits on aircraft using heavy flak are basically pure luck how did this fuze do so well compared to previous models using essentially the same time fuze technology?

4. How do the Germans handle the ammunition shortage created by massive use of flak? Yes, historically this was the case by late 1943 - early 1944.

[Lars]

"In a major trial in the Munich area in April 1945, the new dubbel fuse (Doppelzünder) was tested. The new fuse consisted of both a time fuse and an impact fuse. With the new fuse the heavy Flakwaffe achieved ten times the usual results!!"

Comment: I believe that the Doppelzünder and the "direct fire instead of time fuse" may be one and the same thing. Both were reported at the very end of the war and both were said to be much more effective than the hithero used time fuses. The problem with time fuses was that they exploded below the air craft in may cases plus it took time to set the fuse, missing valuable time. The Doppelzünder may be direct fire at the air crafts by use of the impact fuse, and should the shell miss the air plane, the shell exploded before it hit the ground, by simply setting the time fuse on max.

[PMN1]

The RAF would probably have switched to very low-level attacks (especially with Mosquitos) which the big guns would have found very difficult to deal with. So the Germans would have responded with more light flak around targets. So the RAF would have responded by sending in Mosquito fighter-bombers to take out the light flak before the bombers arrived, and so on...

The Mosquito was the lost chance of the RAF. A fleet of Mosquitos instead of Lancasters would have meant several "Hamburgs" instead of only one. Still, making the entire RAF and USAAF four engine bomber fleet obsolete simply by improving the fuzes of the flak shells would be a heavy blow to the Allies. Besides, switching to Mosquitos would take time AND persuasion of Bomber Harris.

Mosquito's effectiveness was partly due to its elite status. The best navigators and selected pilots were used, as they were often required for Pathfinder missions. Expanding their role to the entire Bomber Command would be like trying to build an entire army group of snipers. The overall result would be diluted by the expansion.

Also the Lanc could carry nearly 5 times the bomb load to the same range.

I will have to check, but perhaps their wooden construction was difficult to mass produce in greater quantity? Can anyone provide better data on this?

You would probably have problems with the manufacturing capacity to get all the Mosquito you would want but there were metal high speed bomber designs such as the Hawker P.1005 which in theory could be built in place of the heavies. Engines (Sabre) would be a problem but with less Merlins being needed??

[phylo_roadking]

You would probably have problems with the manufacturing capacity to get all the Mosquito you would want

IIRC by the high point in Mossie production they were running out of subcontractors able to warp and shape plywood - furniture makers, piano builders, boatyards etc. - for they were competing with the needs of the RN for shaping wood for MTBs, RAF rescue launches, etc., etc...

But then again - the attrition rate would have been lower...

[EKB]

You would probably have problems with the manufacturing capacity to get all the Mosquito you would want

IIRC by the high point in Mossie production they were running out of subcontractors able to warp and shape plywood - furniture makers, piano builders, boatyards etc. - for they were competing with the needs of the RN for shaping wood for MTBs, RAF rescue launches, etc., etc...

But then again - the attrition rate would have been lower...

Or not.

Bill Sweetman claimed that during the first year of operations, Bomber Command Mosquito squadrons had a loss rate of 6.7% aircraft missing in action. He also wrote that during the first six months of those operations, the attrition rate was even higher at 8% while the turreted night bomber squadrons had a loss rate of only 5%.

I doubt if there was a significant difference in bombing accuracy when dropping from the same heights.

105 Squadron was the first on Mosquitos to have a go at high-altitude bombing, and the results were not encouraging. More to the point, formation bombing does not work if the formation is dispersed before it ever reaches the target. With no turrets or other defensive guns, Mosquitos could not hold formation after they came under attack. All they could do is eject their bombs early, and flee. Mosquito pilots could not run the engines at high power for the entire mission, lest they deplete their fuel supply. Emergency engine boost was limited to about five minutes; and that was not very comforting when 500 miles from home.

It did not take long for the RAF to figure out that the best defense for Mosquito bombers was avoiding detection for as long as possible. Even if one could eliminate all engine noise, radar returns, and vapor trails, massed bombing did not lend itself to being stealthy. The result was that Mosquito bombing squadrons changed their preference to low-level attacks, typically confined to eight aircraft or less to further reduce the probability of early detection.

Maybe if dependable smart bombs were available in 1940, a better case could have been made for putting more emphasis on precision low-level air strikes against certain targets. Small strike packages of light bombers could not do enough damage with the weapons then available.

[phylo_roadking]

Bill Sweetman claimed that during the first year of operations, Bomber Command Mosquito squadrons had a loss rate of 6.7% aircraft missing in action. He also wrote that during the first six months of those operations, the attrition rate was even higher at 8% while the turreted night bomber squadrons had a loss rate of only 5%.

However - what did the Heavy Bomber Force's average loss rate CLIMB to at its highest...vs. what did Bomber Command's Mossie squadrons' loss rate decline to?

Also - IIRC those original loss rates were prejudiced by the BC's use of Mosquitos in the Pathfinder role

[BDV]

But I still think that the german air-defence could have been much better organized. In particular a 12.8 cm heavy flak Wand aus Feuer on the western border, exacting its toll on planes both coming and going.

Of course that starts the cycle of Allied measures against the WaF, and german responses to them, BUT bombs falling on the WaF are not falling on factories and cities.

[EKB]

Bill Sweetman claimed that during the first year of operations, Bomber Command Mosquito squadrons had a loss rate of 6.7% aircraft missing in action. He also wrote that during the first six months of those operations, the attrition rate was even higher at 8% while the turreted night bomber squadrons had a loss rate of only 5%.

However - what did the Heavy Bomber Force's average loss rate CLIMB to at its highest...vs. what did Bomber Command's Mossie squadrons' loss rate decline to?

Also - IIRC those original loss rates were prejudiced by the BC's use of Mosquitos in the Pathfinder role

You've got it backwards.

The loss rate of Bomber Command Mosquitos declined only after they were withdrawn from the strategic bombing mission. They were retasked with target marking, nuisance raids, weather reconnaissance, and other specialty roles. 105 Squadron and 139 Squadron proved that it was not a realistic option to replace heavy bombers with a light bomber that was poorly armed with defensive weapons.

[phylo_roadking]

The loss rate of Bomber Command Mosquitos declined only after they were withdrawn from the strategic bombing mission. They were retasked with target marking, nuisance raids, weather reconnaissance, and other specialty roles. 105 Squadron and 139 Squadron proved that it was not a realistic option to replace heavy bombers with a light bomber that was poorly armed with defensive weapons.

Withdrawn from strategic raids?

I know its only Wiki, but it's all I have to hand tonight -

The Light Night Striking Force was an outgrowth of the Pathfinder Force use of the Mosquito bomber. Both fast and long-ranged it could carry a sizeable bombload. Under 8 Group, the number of Mosquito squadrons was built up. These were used for harassing raids on Germany.

To the two (Oboe-equipped) Mosquito squadrons already in Pathfinder Force added a third (No. 139) in June 1943 which Bennett intended to use for diversionary raids to draw the German nightfighters away from the Main Force.

In February 1944, an entirely Mosquito raid was successfully carried out against Düsseldorf. It was formed of the usual marker aircraft from 105 Squadron, 692 Squadron Mosquitos each carrying a single 4,000 lb "cookie" and backup aircraft with 500 lb delayed action bombs.

With Harris' support, Bennett formed more Mosquito squadrons to expand the LNSF; giving him 9 bomber squadrons as well as the Oboe-equipped markers and 8 Group's own meteorological Mosquitos. Over two years, the LNSF achieved 27,239 sorties. Their best month was March 1945 with nearly 3,000. This was achieved for the loss of just under 200 aircraft lost on operations or "damaged beyond repair".

The PFF flew a total of 50,490 individual sorties against some 3,440 targets. At least 3,727 members were killed on operations.

"Over two years, the LNSF achieved 27,239 sorties. Their best month was March 1945 with nearly 3,000. This was achieved for the loss of just under 200 aircraft lost on operations or "damaged beyond repair""

I wonder what the total aircraft loss for the Heavy Force was over that same 2-year period?

[phylo_roadking]

I wonder what the total aircraft loss for the Heavy Force was over that same 2-year period?

While I don't have it divided out by year by type, I DO have aircraft totals (so far identified) for 1944 and 1945 for ALL of Bomber Command...

4639 aircraft lost in 1944 and 1945 up to VE Day.

I might have this the wrong way round ( in y normal fashion) but doesn't that mean that Mossie losses only make up 4.3%?

I wonder what the sortie totals comparison would look like?

[stg 44]

Too late, the Germans discovered that dispensing with time-fusing and firing at the bomber directly, with the intent of a direct hit , rather than a burst barrage, was much more effective, with a much higer rof. This discovery in the last months of the war, resulted in a sudden spike in bommber losses, but too late. If they had employed time-fuseless direct fire in 1943, even without proximity fuses, Allied losses might have become a schtickel vicious.

I know this reply is WAY out of date, but I wanted to discuss this issue in context. Based on the research I've done on the very limited info available on this the German Doppelzünder did not dispense with the timed fuse, it doubled up the fuses, adding a contact fuse to the standard mechanically timed fuse, which made the existing shells more complex, but more effective at the same time.

"In a major trial in the Munich area in April 1945, the new dubbel fuse (Doppelzünder) was tested. The new fuse consisted of both a time fuse and an impact fuse. With the new fuse the heavy Flakwaffe achieved ten times the usual results!!"

Comment: I believe that the Doppelzünder and the "direct fire instead of time fuse" may be one and the same thing. Both were reported at the very end of the war and both were said to be much more effective than the hithero used time fuses. The problem with time fuses was that they exploded below the air craft in may cases plus it took time to set the fuse, missing valuable time. The Doppelzünder may be direct fire at the air crafts by use of the impact fuse, and should the shell miss the air plane, the shell exploded before it hit the ground, by simply setting the time fuse on max.

As far as I can tell they were not. They added a contact fuse to the existing mechanically timed burst fuse. They were more effective in that they kept the bonus of the shrapnel damage, but allowed the direct hit shells to actually detonate rather than pass through a bomber. The issue with the shells bursting too low remained, but depending on what type of shell it was, the like brandschrapnel shell, that actually through incendiary materials upwards at bombers, but they needed to be very careful about using those near woods or cities because they had thermite and could cause fires on the ground if the submunitions fell back to earth.

So creating a direct hit shell to mix in with the box barrage Doppelzünder shells might have been very helpful, but the double fuse seems to still use the shrapnel effect as well as adding a direct hit capability.

[T. A. Gardner]

A better fuze alone is going to do next to nothing to help German flak improve its performance. What the Germans needed was something akin to the US M2 90mm coupled with the SCR 584 radar and M9 fire control computer. That combination, with proximity fuzes made the M2 so much more effective that the battery size was cut from 6 to 4 guns with no reduction in effectiveness.

The M2 was a powered mount slaved to the fire control system that used an automatic power rammer system for loading. The radar made the fire much more accurate and whether using time or proximity fuzes. The power fuze setter / rammer meant when using time fuzes that the time delay between setting the fuze and firing was shorter reducing the inaccuracy inherent in that step.
The M9 system allowed the battery to be controlled centrally with the guns tracking a target using power on the mount to drive the guns. This reduced operator error and improved accuracy again.

Post WW 2, the British adopted similar systems with their 3.7" retrofitting them, as did the Italians with their 90mm. This sort of system became the standard for heavy AA guns until those disappeared being replaced with SAMs.

As for box barrages, these were horridly costly in terms of shell use. A typical one might eat anything from a few thousand to tens of thousands of shells being fired usually for very few enemy losses.

[Paul Lakowski]

sound good but not that much more high tech than SAM TECH.... possible but just as unlikely - to little to late?


considering...

In 1944 Flak accounted for 3,501 American planes destroyed, enemy fighters shot down about 600 less in the same time period.

In 1944 the average amount of rounds used to down a bomber
(4 engines) was :
16000 8,8cm (flak 36/37)
8500 8,8cm (flak 41)
6000 10,5 cm
3000 12,8cm

flak numbers ... inventory numbers...

1944 = 9470 x 88 flak 36 x 20= 189,000/16,000= 11.84
500 x 88 flak 41 x 20 = 10000/8500= 1.17
= 3000 x 105 flak x 12 = 36000/6000= 6
= 829 x 128 flak x 12 = 9948/3000= 3.31

22.33 TOTAL

if all 88 PAK are built as 88 Flak 41 [3.7/7.8] and all 5" guns are built as flak [PAK-FLAK = 10.1/13]
1944 = 7072 x 88 flak 36 x 20= 140,540/16,000= 8.78
2700 x 88 flak 41 x 20 = 54,280/8500= 6.39
3000 x 105 flak x 12 = 36000/6000= 6
1027 x 128 flak x 12 = 12324/3000= 4.11
25.28 TOTAL

So if all 128mm guns & 88L7x are built as FLAK then it should produce a 13% Increase in potential flak fire power.....3964 American planes shot down instead of 3501.