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

  • Thread starter Deleted member 1487
  • Start date
One of the issues with flak shells was that the technology of the day was not accurate enough to ensure that the shells exploded at the exact height - the tolerances involved were so great that the differences between desired detonation point and potential detonation were many many times the effective blast radius meaning that even when a 'box' formations altitude was known the vast majority of the shells would detonate too early or too late to even have a chance of damaging any planes

So the idea of using 'impact' shells is not actually that daft

Also an impact fuse is much easier to make an more robust than a Prox fuse or timer type

I read an idea many years ago which may have been along these line and that was to use smooth bore guns firing sabot shells.

The idea being that a faster 'Saboted' shell can get to altitude quicker and be 'relatively' more accurate than a conventional flak shell of the same calibre - the shell can get away with being smaller as a direct hit requires far less explosives than a flak shell to bring down a four engined bomber.
 

Deleted member 1487

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.....
Right the Axis History Forum thread on FLAK sparked my interest once again. I'm not sure what the deal with the subcaliber munitions are, AFAIK despite efforts with them they never not into service, while the traces in the base issue might be problematic, as base bleed technology led to inaccuracy due to the turbulence caused by the smoke, while the Germans already added tracer components to normal shells to be able to see where their shots were headed. I think the aforementioned book mentions that. There wasn't a noticeable increase in velocity AFAIK.

So in your opinion introducing contact fusing in 1942 would be lethal to the Allied bomber offensive?

Why did the Germans not use contact fuses in the first place?

Also what is your source on German Operations Research and their conclusions about contact fusing? I didn't see anything about that in the FLAK book other than mentioning the new shell.
 

Deleted member 1487

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.
How was this not debunked/pushed back on?
 
I've looked at a lot of AAA damage photos to B-17s and B-24s

Can't say I recall any that were 88mm thru and thru shots that would have been the hallmark of all these supposed direct hits by time fuzed shells
 
So in your opinion introducing contact fusing in 1942 would be lethal to the Allied bomber offensive?

Dangerous to a nascent 8th airforce, bombing in clear conditions by day in rigid combat boxes, you could probably double or triple the losses to flak. More importantly you might make the bombers jink and weave on their bomb runs, spoiling bombing accuracy. Edit: for normal AA shells you would probably be looking at a similar loss rate to flak from contact fused versus time fused shells, with flower pot sabots you might get increased losses, smoothbore sabots, maybe higher losses again.

Why did the Germans not use contact fuses in the first place?

Why did no one else? take your pick: military inertia, lack of interest, alternative technology, lack of a recognised military need until too late etc, etc.

Also what is your source on German Operations Research and their conclusions about contact fusing? I didn't see anything about that in the FLAK book other than mentioning the new shell.

My sources on German ORS range from Rossler's 'The U-Boat' to Overy's 'Why the allies won' to numerous other tomes, such as 'Strategy for defeat: the Luftwaffe 1933-1945' and 'German Secret Weapons of the 2nd World War by Ian V. Hogg.

Hogg goes into a little detail about smooth bore AA sabot guns and their shells, which were based on the experimental Peenemünde Arrow Shells (Peenemünde Pfeilgeschoss or PPG) designs. Hogg also notes extensive research done on the 10.5cm Flak gun sabot round using an 88mm shell as the sabot (the sabot being of the so called 'Flower Pot' type).

Krupp in Essen were researching at the wars end the following AA shells:

8.8cm/7.0cm shell for 8.8cm Flak 16 and 41
10.5cm HE Flak shell
10.5cm/8.8cm Flak shell
12.9cm/7.5cm Flak shell

Niedersachsen AG were also working on similar Flak shell projects at the time.

My opinions on the Teutonic psyche are mine and mine alone... The Flak book does go into a little detail about what led to the contact fused shell, but it is frustratingly brief on the topic.
 
Last edited:
I've looked at a lot of AAA damage photos to B-17s and B-24s

Can't say I recall any that were 88mm thru and thru shots that would have been the hallmark of all these supposed direct hits by time fuzed shells

There were very few direct hits on bombers in general, and in general a bomber that took direct hits form flak tended not to last long enough for damage photos to be taken.

The points being raised here is that the Germans seem to have determined that abandoning time fused shells was worthwhile from an operational point of view as simple contact fused shells gave you the same (or better) chance of shooting down a allied heavy bomber.

The Germans invested quite a bit of research into Sabot AA rounds, I think that this research realised that the quicker you get a shell to altitude the less effect aiming errors and aircraft manoeuvring effects accuracy.
 
my understanding they could replace the timed fuse with tracer? and it had the dual purpose of (somewhat) disorienting effect on Allied pilots?

(thought the timed fuses, even in scenario of reduced number of flak shells expended crucial materials?)
 

Deleted member 1487

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'.
Maybe a Prussian thing, but the Germans were very much all about the why, they weren't called the land of poets and thinkers for nothing.
 
Maybe a Prussian thing, but the Germans were very much all about the why, they weren't called the land of poets and thinkers for nothing.

Yes the Nazi's were renowned for its support of poetry and free thinking, never constrained by rigidity of dogma :rolleyes:
 

MrP

Banned
Yes the Nazi's were renowned for its support of poetry and free thinking, never constrained by rigidity of dogma :rolleyes:
In a perverse sense they were. Unlike in Communism, there was no dogma in Nazism: it was whatever the infallible Führer said it was. He could say white one day and black the next, and that would be fine, because his saying it was its own dogmatic justification. Whereas Stalin needed to justify his policy decisions, however hypocritically, by coming up with the requisite interpretation of Marxist-Leninist holy writ.
 

Ian_W

Banned
The source for the claim was a military report,\

So.

We have a Nazi state that is very clearly and very obviously losing the war.

We have a Nazi state that is addicted to wonder weapons, and that is quite sure they will create a second miracle of Frederick the Great and save Germany.

You'd need to be an exceptionally gullible fantasist to believe that the memo, that says in essennce "Sure boss, that wonder weapon that you said would work and win the war is absolutely working and will win the war" means anything other than "I dont want to get shot as a defeatist".
 
I'm not sure how many planes were shot down by being hit by a 15kg lump of metal (even if it didn't explode), but I suspect most planes that were actually hit didn't come back to tell about it.

However claiming a 10-fold increase in kills seems to contradict the logic.

Assuming the height of explosion is the only changed factor, with times shells we have three bands.
(1) Shells which explode too low, and don't do ant damage.
(2) Shells which explode at the right height, which may or may not kill/damage the bomber. Some of these might have hit.
(3) Shells which explode too late, not doing any damage. Since they've gone past the bomber, they obviously didn't hit.

So the improvement in a direct-contact fuse is to remove the shells in group 1 and hope they hit.

Given the number of shells needed for a kill, the middle zone is probably small compared to (1) and (2). But even assuming its negligible, as half the shells passed without a hit, you most certainly aren't going to get 10 times the kills.

Now it seems there would be an improvement. And IF you planned for contact fuses in advance, you could, for example, use a smaller higher velocity gun with a better rate of fire, and the cost of the shells would come down. All useful things. But with just a new fuse in the existing guns, I don't see a tremendous improvement. Its likely that zone 3 is nearly half the shells fired, so the best is likely to be a doubling, and in practice I think it will be less.
 

Deleted member 1487

Yes the Nazi's were renowned for its support of poetry and free thinking, never constrained by rigidity of dogma :rolleyes:
Come on not all Germans were Nazis. Also the Nazi movement was a romantic one in the literary sense.
https://en.wikipedia.org/wiki/Romantic_nationalism

So.

We have a Nazi state that is very clearly and very obviously losing the war.

We have a Nazi state that is addicted to wonder weapons, and that is quite sure they will create a second miracle of Frederick the Great and save Germany.

You'd need to be an exceptionally gullible fantasist to believe that the memo, that says in essennce "Sure boss, that wonder weapon that you said would work and win the war is absolutely working and will win the war" means anything other than "I dont want to get shot as a defeatist".

Its not a report to Hitler or anyone like that, its an internal report about what happened at the front for military use, which were accurate throughout the war.
 
it was what could be confirmed from wrecks.

Even counting wrecks is not 100% right. In an area as comparatively small and as densely populated as the South East of England WWII wrecks still get dug up that were either never officially logged or got lost in the paperwork. An area as large as Germany there must still be wrecks to find in places like the Black Forest and the Vogelsberg. Any performance metric needs to have a built in error or it leads to bad conclusions.

If the Germans thought they could increase kill rates by a unrealistic value they risked throwing too much effort into a system that costs too much per kill. Even at the bloodiest time of the RAF night bombing campaign Britain was spending less money on Bombing ops than Germany was spending defending itself. I have seen figures that Bomber Command used between 7 and 12 % of Britains war budget and defence of Germany used up to 30% of the German war budget.

A really radical solution might have been stop spending money on any AA bigger than 50mm to prevent bombers going in low for accuracy, increase the Nightfighter budget and use all those 88 and 105mm guns, shells and men where they might be more useful.
 

Deleted member 1487

A really radical solution might have been stop spending money on any AA bigger than 50mm to prevent bombers going in low for accuracy, increase the Nightfighter budget and use all those 88 and 105mm guns, shells and men where they might be more useful.
That's nuts:
https://en.wikipedia.org/wiki/5_cm_FlaK_41
The effective firing range was 10k feet. B17s and Lancasters were at near peak accuracy between 12-14k feet. That would be letting them run riot over Germany. Expanding the night fighter force wasn't going to fix things either, as FLAK was a critical component to backing the bombers off and reducing their accuracy, while NFers were only achieving slightly more kills and a lot less damage on bombers.
 
Thats why I said it was radical, if you are spending 2 to 3 times the money defending yourself against an enemy then eventually you run out of money and they win. Doesnt matter how many bombers got shot down they were still coming and before late 44 they are often still missing anything smaller than a 250,000 population town. Is it economically better to spend that money in artillery for the Army you can get a lot of 105mm and 150mm howitzers for the price of a battery of 88 or 105mm high velocity guns. If every building in Germany is missing a roof industry still carries on as real life showed.

How many battles in Russia, Africa and west Europe could have gone another way with a doubling or trebling in the artillery park. Despite what people like to think its Artillery that often won battles, tanks and planes just decided the score.

Statistics often tell us something different to what seems logical there is a fascinating book called Moneyball https://en.wikipedia.org/wiki/Moneyball about Baseball statistics and how some nerds realised that accepted ways of recording Baseball didnt tell the story of sucess. Dont know much about Baseball but its eye opening on how using counterintuitive ways of recording hits runs and outs could bring sucess.
 
USN vs Japan

Type Rounds fired Kills Rounds per bird

5" VT 117,915 346.5 340
5" Com 223,770 342.0 654

VT almost doubled effectiveness, by being close enough for the radar fuze to work, and also these were director aimed at single targets, and that Mk 37 radar assisted director was the best in the world.


I just am not seeing contact fuzing increasing things that dramatically, unless you have the Nazis begin director firing at individual aircraft, than trying to throw as many shells into the bomber box area as was possible.
 
Top