Doppelzünder FLAK shell introduced in 1942, effects on air war?

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Deleted member 1487

We've had repeated discussions about an improved German air defense system late in the war, but in reading a bit about it recently in this book:
http://www.abebooks.com/9780700614202/Flak-German-Anti-Aircraft-Defenses-1914-1945-0700614206/plp
there was a pretty minor buff that apparently would have had major consequences for the air war, which was the introduction of a Doppelzünder (double fuse) shell, which essentially was the normal FLAK shell with an added contact fuse and dramatically lowered the number of shells needed to shoot down a bomber:
In the final weeks of the war, the ammunition shortage within the flak arm became acute. The critical situation led the Luftwaffe to test a projectile with a contact and timed fuse (Doppelzünder), the same round that a member of Speer's ministry refused to support in 1944, based on safety considerations involved with the transportation of these munitions. During combat trials in Munich on April 9, heavy flak batteries using these rounds brought down thirteen aircraft at the cost of a mere 370 rounds per shootdown, an extraordinarily favorable ratio compared with the existing average of approximately 4,500 rounds.158

It seems like a remarkably easy addition even though it would make the shells somewhat more complex and expensive to make, but due to reduced ammo expenditure it would more than offset the decreased supply of shells.

If it were thought of and introduced after combat testing by mid-1942 what impact would that have had on the strategic air war? I'm assuming the attack was during the day by a bomber box, so the night missions might be less affected.

How would the Allies react and counter it? I've heard suggestions that they might turn more to Mosquito and medium bombers and avoid deeper raids, while turning to night attacks if they were less dangerous. Of course a significant issue in 1942-43 is the FLAK arm was limited in size compared to 1944-45, so while probably at peak efficiency in 1942-43 before Window and jamming was introduced, there weren't enough batteries to defend all cities and there was declining trained manpower, as men were combed out for the front leaving young boys, old men, and girls/women to work the guns; their training was not particularly thorough come 1943 when the comb outs really got going due to the raiding of training schools for equipment for the front.

Might the Allies grit out the losses and keep going because they could eventually rely on jamming, declining FLAK crew quality, gaps in defenses, and FLAK suppression missions?
 
It's basically rearranging deckchairs on the Titanic, by this point the Germans have lost no matter what new weapons they come out with.
 

MrP

Banned
That raises the possibility of resource reallocation to some other type of artillery munition, like antitank rounds (though I'm not sure if those were in short supply). Also, fewer rounds necessary to down airplanes mean slower wear of the barrels.
 
If the improvement is that dramatic, I'm thinking WAllied bomber losses are likely to climb pretty steeply.:eek:

It also strikes me the improvement in effectiveness would reduce the demand for AAA, making them available for the Eastern Front.

Whether that hurts the Sovs enough to make a real difference, IDK. I doubt it...
 

Deleted member 1487

It's basically rearranging deckchairs on the Titanic, by this point the Germans have lost no matter what new weapons they come out with.
Right, the point isn't about this winning the war, rather how the Allies and Axis respond given the strategic implications of this more effective shell.

If the improvement is that dramatic, I'm thinking WAllied bomber losses are likely to climb pretty steeply.:eek:

It also strikes me the improvement in effectiveness would reduce the demand for AAA, making them available for the Eastern Front.

Whether that hurts the Sovs enough to make a real difference, IDK. I doubt it...
Given that they were something like 11x more effective than existing shells...
But that was at the end of the war, they brought down 13 bombers out of an unknown number, and we don't really know the circumstances. I think they would be less effective at night, especially once the RAF jamming kicked in about mid-1943. Likely the demand for AAA stays the same given they had shortages of tubes to defend all the targets that were being threatened and were forced to transfer them around a lot in 1942-44 to try and economize.
 
To assess if the promising result is real or not we need to ask a few questions:
Were the 13 'claimed' aircraft actually confirmed as shot down? Certainly in air-to-air combat claims were often vastly overstated. Ground-to-air combat it's less of an issue (you can find and count the wrecks) until the frontline starts to get close... I'm not sure of the exact line on the 9th of April, but certainly by the 30th allied forces had reached Munich. Without being able to chase up the wrecks the Germans may be giving figures based upon what was seen from the ground, and if several people see the same aircraft going down you may see it counted two or three times.

If so, can all 13 losses be attributed to the new shells, rather than other sources? If you've got two batteries banging away with the new shells and another half-dozen with the old shells, it's possible that many of the aircraft shot down would have been brought down by the batteries equipped with ye-olde shells. If you then have a raging boner for Napkinwaffen and, hence, divide all losses in that general area by shells fired by the two batteries with the new ammo you could easily come up with an incorrectly good performance.

Was this particular occasion a typical bombing raid or something out of the ordinary? April '45 isn't typical... the Luftwaffe has ceased to exist; a lot of industrial targets have been wrecked or captured... the Bomber Command is flying during daylight hours! If the allied bombers were acting in a more tactical roll, or if the poms' were sending a bomber stream over during daylight (when visual direction systems work well) then the losses may not be applicable to more normal operations.

Edit: I'd go so far as to state I strongly suspect one of more of these factors is at play. A supposed 11 times improvement in kills by adding a contact fuse implies a hell of a lot of direct hits, but a 9kg lump of steel and explosive hitting a plane at several hundred meters a second is going to do nasty things to an aircraft even if it doesn't go bang... you may expect a few constructive total losses to be turned into fire balls and crashes, but I wouldn't expect kills to rise that drastically.

Of cause, if the numbers are right, and if the performance was achieved against a typical bomber-raid, then, well, it'd imply that certainly daylight operations would take heavy losses rendering them impractical...
 
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Right, the point isn't about this winning the war, rather how the Allies and Axis respond given the strategic implications of this more effective shell.
Okay, good for the Germans, as it would discourage area bombing, thus you don't see as many cities flattened (either because they don't do it, or because they take time first to ensure all the flak is gone). Comments about barrel wear, relocation of guns, etc. are also true, so they do slightly better on the fronts.
 

Deleted member 1487

To assess if the promising result is real or not we need to ask a few questions:
Were the 13 'claimed' aircraft actually confirmed as shot down? Certainly in air-to-air combat claims were often vastly overstated. Ground-to-air combat it's less of an issue (you can find and count the wrecks) until the frontline starts to get close... I'm not sure of the exact line on the 9th of April, but certainly by the 30th allied forces had reached Munich. Without being able to chase up the wrecks the Germans may be giving figures based upon what was seen from the ground, and if several people see the same aircraft going down you may see it counted two or three times.

If so, can all 13 losses be attributed to the new shells, rather than other sources? If you've got two batteries banging away with the new shells and another half-dozen with the old shells, it's possible that many of the aircraft shot down would have been brought down by the batteries equipped with ye-olde shells. If you then have a raging boner for Napkinwaffen and, hence, divide all losses in that general area by shells fired by the two batteries with the new ammo you could easily come up with an incorrectly good performance.

Was this particular occasion a typical bombing raid or something out of the ordinary? April '45 isn't typical... the Luftwaffe has ceased to exist; a lot of industrial targets have been wrecked or captured... the Bomber Command is flying during daylight hours! If the allied bombers were acting in a more tactical roll, or if the poms' were sending a bomber stream over during daylight (when visual direction systems work well) then the losses may not be applicable to more normal operations.

The source for the claim was a military report, so I'm assuming they confirmed because direct hits from 88s don't result in bombers getting very far. AFAIK to be claimed as a FLAK kill you must have the wreck, claims aren't counted unless confirmed and these weren't claims AFAIK. AFAIK the combat test was conducted by FLAK only equipped with the new shell, nothing else to mess up stats. Your last point is very valid and I don't have an answer; I'm assuming a daylight raid, hence why I doubt its full effectiveness at night. I doubt they did a low altitude mission because FLAK was still a threat right up to May 1945. I think it was against the USAAF because Munich was in their zone of advance and any support missions were not going to be done by Poms.
 

Saphroneth

Banned
That's a greater improvement than you'd get from using VT fuzes - AKA "magic fuzes which explode when the enemy is nearby". I'm skeptical.
To say the least.
 

Deleted member 1487

That's a greater improvement than you'd get from using VT fuzes - AKA "magic fuzes which explode when the enemy is nearby". I'm skeptical.
To say the least.
VT fuses were pretty much used against low level fast moving targets during the later parts of WW2, not against bomber boxes a 25k feet; in terms of box barrages a lot of shells are wasted with the timed fuses that would have had direct hits had they had contact fuses; so you get the best of both worlds with these shells, direct hits when they happen and the effects of box barrages on bombers.
 
It depends. How many aircraft were shot down by Flak compared to the entire number of strategic bombers?

For example, if OTL only 1% of B17s and Lancasters were shot down, at best you increase that to 10%. So, little effect though it increases Allied costs.

If the number is 10%, you probably get diminishing returns, but it certainly gives a reprieve.

So, you need a number.

At worst, the Allies give up on strat bombing and focus on bombing away logisitics in France, where there are less 88s, and focus the war effort on taking France and beating the Germans on the field. The war doesn't last much longer, but more German civilians survive.
 

Deleted member 1487

Sbiper would know. :cool:

My guess is heavier daytime causalities means more nighttime runs for the RAF?
You mean USAAF? The RAF was already going by night in 1942. Perhaps the USAAF would try and get a bloody nose, switching the night some time in late 1943, probably staying restricted to France in 1943-44 during the day. Then letting their fighters go nuts in Germany in 1944, because the 88 shell doesn't impact them.
 

Saphroneth

Banned
VT fuses were pretty much used against low level fast moving targets during the later parts of WW2, not against bomber boxes a 25k feet; in terms of box barrages a lot of shells are wasted with the timed fuses that would have had direct hits had they had contact fuses; so you get the best of both worlds with these shells, direct hits when they happen and the effects of box barrages on bombers.

Even if you got the best of both worlds, a VT fuze is basically a time shell that's automatically set to the right amount AND a contact shell with a non-contact range. It is automatically better.

And the quantitative improvement from VT shells is a factor of seven - which is, remember, going from "have to get fuze in right place at right time" to "have to get fuze in right place at any time".

This is supposedly a factor of twelve - nearly twice as good.
 

Deleted member 1487

Even if you got the best of both worlds, a VT fuze is basically a time shell that's automatically set to the right amount AND a contact shell with a non-contact range. It is automatically better.

And the quantitative improvement from VT shells is a factor of seven - which is, remember, going from "have to get fuze in right place at right time" to "have to get fuze in right place at any time".

This is supposedly a factor of twelve - nearly twice as good.
That's the thing the VT shell in WW2 that the Allies used wasn't used the same way the Germans were using their FLAK, so perhaps VT then would have been several times better against high altitude bomber boxes when used en masse as 88s were than it was against the lower level targets of OTL 1944-45. Massed FLAK tended to do well against tight bomber formations relative to spraying 20mm shells at individual Kamikazees.
 
The source for the claim was a military report, so I'm assuming they confirmed because direct hits from 88s don't result in bombers getting very far. AFAIK to be claimed as a FLAK kill you must have the wreck, claims aren't counted unless confirmed and these weren't claims AFAIK.
Okay, that's a reasonable explanation as to why they'd be confident in the number of kills.
AFAIK the combat test was conducted by FLAK only equipped with the new shell, nothing else to mess up stats.
This is a bit more difficult to believe. Assuming the quote accurately reflects the situation... You've got a new experimental fuse and manage to roll it out to all the gun batteries around a major city, and not just in niche quantities but in sufficient quantities to replace all old fuses? It's not out and out impossible but it does seem unlikely.

Either that or the quote doesn't reflect the true situation, and the AA guns and bombers were concentrated on a smaller target distinct from the city of Munich itself.

Edit: There's also the whole single datapoint issue. With only a single test there's no way of knowing if the performance was typical or happened to be an outlying case.
 

Deleted member 1487

Okay, that's a reasonable explanation as to why they'd be confident in the number of kills.
This is a bit more difficult to believe. Assuming the quote accurately reflects the situation... You've got a new experimental fuse and manage to roll it out to all the gun batteries around a major city, and not just in niche quantities but in sufficient quantities to replace all old fuses? It's not out and out impossible but it does seem unlikely.

Either that or the quote doesn't reflect the true situation, and the AA guns and bombers were concentrated on a smaller target distinct from the city of Munich itself.

Edit: There's also the whole single datapoint issue. With only a single test there's no way of knowing if the performance was typical or happened to be an outlying case.

Indeed the single data point is probably not representative, so I'd say that a 3-4x shells per shoot down improvement is probably more likely. From what I understand they were forced to use the new shells due to supply issues, so its actually not that crazy to believe that equipped all batteries with them. Also even if not why the crazy decrease in shells per shootdown? If using the old sells then the normal 4500 shells per shootdown would hold, the only variable being altered was the new shell introduction on the German side.
 

Saphroneth

Banned
Indeed the single data point is probably not representative, so I'd say that a 3-4x shells per shoot down improvement is probably more likely. From what I understand they were forced to use the new shells due to supply issues, so its actually not that crazy to believe that equipped all batteries with them. Also even if not why the crazy decrease in shells per shootdown? If using the old sells then the normal 4500 shells per shootdown would hold, the only variable being altered was the new shell introduction on the German side.
Well, if they fired off (say) 3500 of the old shells per aircraft and a few hundred of the new shells, then given the "superweapon" obsession it's entirely possible for it to result in assuming "oh the old shells were crap it must have been the new ones".
 
I actually have the book that is linked in the 1st post of this thread.

The Germans were very poor at Operational Research during WW2, some might argue this was as a result of the strength of the tradition of their General Staff's, others that it was a result of the Germans conscripting Scientists and exempting engineers from military service, typical Teutonic traits of 'all how and no why'.

The concept of contact fused AA shells actually came from nascent German ORS, the Kreigsmarine realised it needed the equivalent of ORS in late 1943 and around the same time so did the Luftwaffe. For the Luftwaffe the first thing they looked at was Flak effectiveness, for the simple reason that Germany could have vastly more flak guns than fighters i.e. it was a resource that could be expanded easily, whereas fighters could not (despite the miracles of production, the Germans lacked trained pilots and then fuel for the thousands of fighters that Speer produced for them).

The Germans went back to 1st principles, they looked at how predicted heavy Flak worked, and they realised a number of things. The most important thing was that given the flight time of heavy AA shells, small variations in the time setting of timed fuzes was of critical importance. Even time fuzes that were matched to within several per cent of each other i.e if set to detonate after say 60 seconds and they would detonate at 59.9, 59.3, 60.2, 60.5 seconds, resulted in the shells detonating outside their lethal radius. Add to this errors in the mechanical predictors, errors in date entry, ballistic variations in shell flight time etc. and it was actually not worth it to bother fitting time fuzes to shells. A simpler impact fuzed shell had about the same probability of shooting down a heavy bomber as had an 'accurately' set time fuze shell. And remember that heavy AA time fuzes were complex and expensive to make, the Armaments Ministry was delighted with these findings and tried to expedite these shells into service.

But here is where service bureaucracy got involved and all sorts of objections were raised, the main one being that it was too dangerous to transport fuzed shells (a total strawman argument). The end result was that very little of these shells were made or used.

With regard to the losses suffered by the allies to these shells, a direct hit will destroy a bomber, prior to this flak usually mostly inflicted damage and rarely killed bombers outright, it was fighters that did the execution. One would have to look into more detail to the losses claimed, if it was in daylight and good weather conditions and against the 8th Airforce, it is certainly plausible that you might be able to shoot down those numbers. At night, or in poor weather and relying upon jammed AAA radars, you would probably not get the same results.

Also by the stage these shells were introduced it would make not one blind bit of difference, the allies could have taken these increased losses for the few weeks that the 3rd Reich had left to live.

Introduce them a year earlier? you probably only increase allied casualties significantly in their bomber forces. Introduce them 2 years earlier and you could strangle the 8th Airforce in its crib and gut RAF Bomber Command.

Now if you replaced your heavy AA shells with sabots and fitted long burn tracers to their base and fitted contact fuzes.....
 
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