Effectiveness of German anti Aircraft Fire

[perseus]

I'm reading about the anti-aircraft defences Germany used to protect the Reich in the latter stages of the war. The anti aircraft shells such as the 88mm were disadvantaged by the lack of an effective proximity fuse. However, it's still surprising how ineffective they were.

Consider the US daylight raids. Wikipedia says

[the bomber combat box] stacked 750 ft (230 m) vertically, 650 ft (200 m) from front to back, and 1,170 ft (360 m) laterally. This final variation presented flak gunners with a small target, produced excellent bomb patterns, and was both easy to fly and control.

This is still a very large area in which to explode a shell, surely any half decent gun battery in daylight couldn't avoid exploding shells inside the box? Worse still in such a confined space each bomber must have been very near to the detonating shell. So it seems that either the AA fire was very inaccurate or that the aircraft were largely immune to most shrapnel.

I performed a few calculations to determine how many rounds would be required to guarantee impacting directly on an airframe by chance. The answer is surprisingly few. Assuming a 200 sq metre area for the B17, these boxes are about 7.5% opaque with airframe! Obviously, it's difficult to miss after 10 rounds. So perhaps smaller more numerous, impact fused shells, which detonate just after contact inside the frame would be more effective than shrapnel? My estimate suggests that a few hundred L70 Bofors guns equipped with such shells would be very effective against such a formation of bombers.

The nightime raids of the RAF over wider spaces would have been rather more difficult to counter since they were far more widely spread, being sometimes hundreds of miles long, however, there were perhaps other means of dealing with these.

What am I missing?

 

[JOC]

German fighters day and night

I'm reading about the anti-aircraft defences Germany used to protect the Reich in the latter stages of the war. The anti aircraft shells such as the 88mm were disadvantaged by the lack of an effective proximity fuse. However, it's still surprising how ineffective they were.

Consider the US daylight raids. Wikipedia say

This is still a very large area in which to explode a shell, surely any half decent gun battery in daylight couldn't avoid exploding shells inside the box? Worse still in such a confined space each bomber must have been very near to the detonating shell. So it seems that either the AA fire was very inaccurate or that the aircraft were largely immune to most shrapnel.

I performed a few calculations to determine how many rounds would be required to guarantee impacting directly on an airframe by chance. The answer is surprisingly few. Assuming a 200 sq metre area for the B17, these boxes are about 7.5% opaque with airframe! Obviously, it's difficult to miss after 10 rounds. So perhaps smaller more numerous, impact fused shells, which detonate just after contact inside the frame would be more effective than shrapnel? My estimate suggests that a few hundred L70 Bofors guns equipped with such shells would be very effective against such a formation of bombers.

The nightime raids of the RAF over wider spaces would have been rather more difficult to counter since they were far more widely spread, being sometimes hundreds of miles long, however, there were perhaps other means of dealing with these.

What am I missing?

I don't have the statistics presently. But by far and away, the greater number of Allied bombers were downed by German fighters. "BTW: Wikipedia can be misleading at times concerning WW2 data"

 

[LeEnfield]

If you think that the German AA fire was ineffective just look at the casualties suffered by the Allied airforce over Germany.

 

[George]

If you think that the German AA fire was ineffective just look at the casualties suffered by the Allied airforce over Germany.

yeah, I'm thinking more B-17/B-24s were downed by A-A than by fighters.

 

[JOC]

protetion by P-51 made the difference by taing out the German fighters

A total of ~ 150,000 allied airmen died in the European theater of WW2. Roughly 1/2 American and 1/2 Common Wealth. The greater part of these were bombers B-19's, Lancaster's and such.
I still hold that the greater % were downed by German war planes than by AA fire. This is the reason the losses of bombers went down considerably in the spring of 44 when the P-51 Mustangs could accompany the bombers anyplace in Germany. They were able to engage the German fighters and greatly reduce the treat since they were built in such large quantities to fly the full distance and with the exception of the ME-262 could out dogfight the German fighters for the most part (depending on the pilot).

 

[perseus]

Unfortunately the truth is less glorious. Safety and pilot training was obviously compromised in war relative to peacetime, and a large number of losses were accidents, sometimes even before they were delivered!

According to the AAF Statistical Digest, in less than four years (December 1941- August 1945), the US Army Air Forces lost 14,903 pilots, aircrew and assorted personnel plus 13,873 airplanes — inside the continental United States. They were the result of 52,651 aircraft accidents (6,039 involving fatalities) in 45 months.

Think about those numbers. They average 1,170 aircraft accidents per month—- nearly 40 a day. (Less than one accident in four resulted in totaled aircraft, however.)

It gets worse…..

Almost 1,000 Army planes disappeared en route from the US to foreign climes. But an eye-watering 43,581 aircraft were lost overseas including 22,948 on combat missions (18,418 against the Western Axis) and 20,633 attributed to non-combat causes overseas.

http://www.wwiifoundation.org/mission/wwii-aircraft-facts/

The Germans suffered even more through five long years of pilot attrition, the final straw were the escorts of the US 8th in the spring and summer of 1944. The US aircraft were good but the US were also able to draw upon fresh young men for this prestigious task. The Luftwaffe were left with very few half decent pilots [ame="https://www.youtube.com/watch?v=b4EASQJ0vJk"]to fly the ME 262[/ame] which was being produced in large numbers in the latter stages of the war. Together with the infrastructure damage and fuel shortage problems it made limited impact.

Some more interesting stats here, each of the major combatant countries had an almost identical number of combat aircraft losses, except for Germany which was only 30% greater. However, the US had the greatest losses in aircrew due to the number of crew in the bombers no doubt!

 

[perseus]

Regarding my contention that German AA was not very effective. I mean far less effective than you would think based on the area covered by aircraft in those compact combat boxes.

American bombers had losses down to 1% per mission once the Luftwaffe (but not the flak) had vanished. Problem is, even small losses per mission mount up over time resulting in the high figures mentioned in my previous post.

 

[JOC]

Continued and all veterans

My point exactly, basically due to P-51 coverage. Once the Luftwaffe fighters were shot down or destroyed otherwise, allied bombing losses went down dramatically.

As for casualties, yes many occur that are not directly a result of combat or as you say "not as glorious". Let me remind you everyone of those men that died was an allied veteran and whether he died in training or as a result of an accident it is no less glorious then that of the men who gave his life for his country fighting.

The USA suffered ~ 300,000 combats deaths in WW2, yet lost ~ 500,000 men in WW2. The x-tra ~ 200,000 died as a result of accidents, disease, friendly fire, exposure, even snakebite in Asia, "the list goes on". All ~ 500,000 of these men gave their life for their country.

 

[Kesse81]

I´ve read somewhere that it took more than 3,000 88-mm shells to shoot down a bomber.

 

[perseus]

I´ve read somewhere that it took more than 3,000 88-mm shells to shoot down a bomber.

Indeed

One Luftwaffe study estimated it took over 3,300 88-mm shells to successfully shoot down a bomber.

http://histclo.com/essay/war/ww2/air/eur/sbc/gd/flak.html

whilst this might not sound impressive the Germans produced something like 25,000 heavy Flak guns.

 

[JOC]

Actually that's not such a high number when compared to the total artillery produced by Germany including: SPA, (self propelled artillery - gun ), mortars, rockets such as the Nebelwerfer, and of course standard artillery pieces such as the pack 43 and 44.

 

[George]

Astounding numbers, & many thought "One a day in Tampa Bay" was bad...

 

[perseus]

It excludes light/intermediate artillery such as 'bofors' type guns which were produced in greater numbers.

Having looked into this further the L70 automatic wouldn't have been available until well after the war, and the L60 only had an effective range uwell below that of the B17s. The Germans used a fast firing 3.7 cm but with a effective firing range of only 4,800 m (15,700 ft). An obvious priority should have been to extend the range of this intermediate automatic flak, something they were surely capable of. Instead they went for developing exotic ground to air missiles which never bore fruit in time. Simply firing canon shells or missiles from aircraft into the box would have been effective as well which was a tactic used by the few Me 262 which got airborne.

However, it still doesn't explain how the Americans were able to maintain such tight 'combat boxes' since even a single 88mm shell would have had a 5% chance of a direct impact assuming it could be fired accurately enough to 'penetrate' the combat box. It makes me wonder if the Germans didn't think swapping to an impact fuse for the large artillery. A timed shell must have just made 'small' holes in the aircraft and exploded outside.

 

[MontyB]

While I am not sure this was part of the German grand plan I would like to point out that there was more advantage in a badly shot up aircraft and crew getting home than there was in bringing that aircraft down.

It consumes far more allied resources to fix an aircraft (for example a replacement engine would be one that never went into an extra bomber) and provide medical aid to wounded crewmen (both at base and at home) that made it home by comparison shooting it down consumes German resources in guarding/feeding and healing downed allied crewmen.

 

[perseus]

While I am not sure this was part of the German grand plan I would like to point out that there was more advantage in a badly shot up aircraft and crew getting home than there was in bringing that aircraft down.

It consumes far more allied resources to fix an aircraft (for example a replacement engine would be one that never went into an extra bomber) and provide medical aid to wounded crewmen (both at base and at home) that made it home by comparison shooting it down consumes German resources in guarding/feeding and healing downed allied crewmen.

Yeah wasn't that the philosophy behind the Schu mine?

that said, I guess downed aircraft and pilots could be a valuable source of raw materials and information. I wonder why they didn't try to patch up allied aircraft from the downed ones. Plenty of spares available!

 

[MontyB]

Yeah wasn't that the philosophy behind the Schu mine?

that said, I guess downed aircraft and pilots could be a valuable source of raw materials and information. I wonder why they didn't try to patch up allied aircraft from the downed ones. Plenty of spares available!

They did patch up the aircraft the could and the rest were recycled but the manpower cost of the PoW camps alone would have furnished a couple of extra divisions alone add to that feeding (even if it wasn't the best quality) and maintaining the health of POWs would have been a fairly major burden on the Reich.

This does not take into account the logistics requirements and subsequent industries and workforces needed to maintain the camps.

Personally if I was Goering I would have hoped just about every aircraft made it home on one engine and with its crew injured enough to be sent home.

 

[JOC]

salvaging B-17 planes - parts

Yeah wasn't that the philosophy behind the Schu mine?

that said, I guess downed aircraft and pilots could be a valuable source of raw materials and information. I wonder why they didn't try to patch up allied aircraft from the downed ones. Plenty of spares available!

Little salvaging was accomplished by the Germans as far as the B-17 were concerned. Of the > 10,000 used to bomb Germany ~ 4150 were shot down in the European theater. However only 40 were salvaged or forced down by the Luftwaffe over the course of the war. The fact is that these planes were high altitude bombers and when they went down usually their was little left.

 

[George]

An obvious priority should have been to extend the range of this intermediate automatic flak, something they were surely capable of. Instead they went for developing exotic ground to air missiles which never bore fruit in time. .

Read somewhere where a German scientist/arms developer said they could have fielded lots of cheap and effective anti-tank guided missiles but the Army kept asking for bigger and heavier A-T guns.

 

[perseus]

Little salvaging was accomplished by the Germans as far as the B-17 were concerned. Of the > 10,000 used to bomb Germany ~ 4150 were shot down in the European theater. However only 40 were salvaged or forced down by the Luftwaffe over the course of the war. The fact is that these planes were high altitude bombers and when they went down usually their was little left.

Considering the shortages of materials, I'm surprised they didn't at least collect and remelt the aluminium fuselage and engine steel. I suppose recycling wasn't the thing in those days! You should get an idea what state a B17 ends up in just by googling B17 crashed. I thought these planes were tough cookies. That said, these are probably landings over friendly territory. Over occupied countries the crew were probably instructed to bail out rather than try to land so the enemy couldn't reuse the plane directly.

sometimes the crews were too low to bail out, as was the case with this Lancaster.

 

[Kesse81]

The wreckage of Allied bomber and fighter aircraft proved to be an important source of raw materials for Germany. The Germans systematically collected all wreckage from the scattered crash sites into scrap dumps both in the Reich and in the occupied territories.

One of these dumps was located at Utrecht in the Netherlands. In November of 1943, this yard alone supplied more than 308,000 pounds of aluminum alloy to German industry. During late 1943, they were scraping approximately fifty Luftwaffe and thirty Allied aircraft each month.

Source: “Strangers in a strange land” by Hans-Heiri Stapfer.

The book deals primarily with captured American aircraft. But there is a section that tells about “How an American bomber becomes a new Messerschmitt”