1944: Flak Alone Blasts the Allies out of the Sky

[Zygmunt]

* When the Allies think that flak is becomming too effective they simply sic their fighter bombers on the sites. Since the majority of the bomber killers would be heavy flak guns this would now require their being protected by light flak guns and the cost of their employment rises expotentially.

The risk here is that with Allied fighter-bombers tied up suppressing enemy air defences for the strategic bombing campaign, German ground forces are (relatively) free to move during daylight hours. Every fighter bomber attacking flak sites in Germany is a fighter bomber not attacking German forces or communications elsewhere in occupied Europe. Lkefct has already alluded to the high attrition rate these aircraft will experience - higher, perhaps, than an ordinary sortie; it is easier to defend a fixed site like a heavy flak battery with light flak than it is a motor convoy. Yes, surrounding flak sites with low-level defences will mean a lot of work for the Axis, but could see dangerously high casualties (especially prisoners - single-engined aircraft damaged at low-level over Germany may not make it back to friendly territory) for the Allied fighter-bombers.

Zygmunt

[Tony Williams]

With WW2 aiming techniques, unguided rockets were too inaccurate to be anything more than area weapons (if you want to hit a specific target, use a gun). So they would be best suited to volley fire at relatively long range, followed up by a close-in gun attack.

The key factor in scoring hits with unguided rockets would therefore be the percentage of the sky occupied by the bombers in a formation: the more tightly the planes are grouped, the more chance of a hit (this is good, because the threat from fighters closing to gun range means that the bombers have to stay close to each other for mutual defence). This means that the worst possible attack angles would be from directly astern or directly ahead, because the bombers make the smallest targets at those angles. Much better is from the side, in a beam attack, but that carries the problem of a maximum deflection shot - the pilot has to calculate how far in front of the bombers to aim in order to hit them, and without a radar gunsight and ballistic computer, that is extremely difficult. Of course, they make the best targets of all looked at from overhead or underneath, but those are difficult angles to attack from

Put all of that together and it is clear that the vast majority of unguided missiles would simply pass by without hitting anything (no doubt they would scare the pants off the bomber crews, which is fine, but not so good as shooting them down).

Of course, if the interceptors have escort fighters to worry about, all of this becomes an order of magnitude more difficult.

So to give you the best chance against the bombing campaign, you need the biggest possible variety of weapon systems for them to worry about. Unguided rockets like the R4M would have been helpful as a part of that, but no way could they have been decisive by themselves.

Tony Williams: Military gun and ammunition website and discussion forum

[Lars]

Regarding the British night bombers a while ago: I agree that the upward firing Schrägemusik gun firing from beneath the British bombers was very effective. But why shouldn´t R4M be a problem for the British night bombers? The Wilde Sau (or was Zähme Sau?) tactics where day fighters attacked British bombers over their target had some sucess, even though the tactics were eventually disbanded and the fighters returned full time to day defense. If the Wilde Sau figters could fire a volley of rockets from a distance of ½-1 kilometers at a bomber caught in the search-lights this would be one thing more to attrite Bomber Command.

Regarding the Allied day campaign: One thing to consider would be Hitler´s low priority of the Reich defense. If Luftflotte Reich armed with R4Ms manages to halt day light bombing in the 1943-1944 period, Luftflotte Reich would surely be starved of planes, pilots and fuel for an endless list of more pressing concerns. The east front was always in a crisis, the Allies landed in Sicily, at Salerno, Anzio, Normandy, Southern France, etc, etc. "Surplus" day fighters (as Hitler would see it) would be thrown away in ground support campaigns, a role for which they were ill trained. This happened in Normandy in the real war.

If the Allied day campaign had been halted, this would almost surely mean an imidiate chance of priorities, whereby Luftflotte Reich would slide to the bottom of the German priority list.

[Tony Williams]

Regarding the British night bombers a while ago: I agree that the upward firing Schrägemusik gun firing from beneath the British bombers was very effective. But why shouldn´t R4M be a problem for the British night bombers? The Wilde Sau (or was Zähme Sau?) tactics where day fighters attacked British bombers over their target had some sucess, even though the tactics were eventually disbanded and the fighters returned full time to day defense. If the Wilde Sau figters could fire a volley of rockets from a distance of ½-1 kilometers at a bomber caught in the search-lights this would be one thing more to attrite Bomber Command.

I believe that you are seriously overestimating the accuracy of unguided rockets. They spread out rapidly to cover a wide cone, like a shotgun blast - which means that big holes rapidly appeared in the pattern. If you are aiming at an individual plane, then even if your aim is dead-on there is a strong probability of a clean miss at anything other than short range.

If Luftflotte Reich armed with R4Ms manages to halt day light bombing in the 1943-1944 period,

That is a HUGE if, and totally unrealistic IMO. I do not doubt that deploying R4Ms would have added to the bomber casualties, but not to the extent that the bombing campaign would have halted.

Tony Williams: Military gun and ammunition website and discussion forum

[Lars]

Watch your blood pressure, Tony I didn´t say halted in the sense of permanently halted. In fact that was exactly my argument that it wouldn´t be permanent even if the Germans were much more sucessful than in the real war. Say, the R4M rockets appearing in 1943 is just what pushes the American day-light bombers over the attrition threashold in the air war over Germany. Schweinfurt, Regensburg and other attacks deep into Germany have an even larger casualty rate. Say again, these larger casualties forces the USAAF to think again and wait for American long range fighers to appear. Hitler and Goering claim "victory" and therefore let the Luftflotte Reich slip down the list of priorites for the benefit of the Luftflotten in Russia and Italy.

When the USAAF resumes its air war over Germany, Luftflotte Reich would have been starved for months.

[Lkefct]

I am not sure that they would even let their priorities slip. Historically, even in the beginning, the USAAF used fighter excort. What was lacking was a plane that had the range to accompany the longer ranged missions. In 1943 there was considerable effort to extend the thunderbolts range by just adding larger tanks. It was never as satisfactory as having the mustang, but in conjunction with British planes, it allows the bombers to extend in belgium and northern germany. They can always drop back to restricting raids in that area until the can get their mustangs.

Additonally, I think the R4M might be a victim of it's own success. Witht eh AT round avaiblie, the demand from the attack squadrons in addition to the bomber killers is going to put an enourmous strain on the production of them. Many German pilots fly multiple sorites per day, each one they would potentially fire off their rockets. Unless production is expanded on a massive scale they will likely be in short supply. In addition to those rockets similar facilities are trying to produce a lot of other rocket launched waepons in massive quantities. If nothing else, I would image that the propellents would eventually run short.

[lazybather]

Guys....at the end of the day, its a what if question............

If and only if the Luftwaffe had brought in to service all the weapons mentioned during this thread, they would have made bombing missions over Germany alot more dangerous for the allies, perhaps soo dangerous they would be convinced to switch permenantly to bombing military targets instead, supprting the ground forces, (this worked well during the early stages of the D-Day landings).

The end result of more effective air defence, would only have led to a more effective ground battle.........and again hasten the German armies eventual defeat anyway?

stuart

[john1761]

lazybather, actual the intial bombing in D day were not that effective. High altitude bombing at that time was not acurate enough. A switch for hvy bombers to med . would increase the tactical air arm. What hvy forces that were left would probably be used at the near operational level once the strategic bomber offensive was drawn down due to losses. But with a less effective strategic bomber campaign you would see a much larger Luftwaffe as their plants were not constantly hit. This might lead to a longer ground campaign.

[lazybather]

Hmmmmmmm.......

John, I thought the RAF bob fleet was 'doing' low level bomb runs on the french rail network, and it did prove successful..........(ie..the Das Reich having to advance north by road instead of rail, seriously delaying its arrival in normandy)...........things like that.....are in the end successful campaigns..............

I suppose with enough bombers hitting the same target over successive days/nights, your bound to hit the target at some point,.........its the law of averages.........somethings going to get destroyed that will hurt the enemies ability to fight?


The antics of the SAS and French SAS are pretty interesting during this period too.......(bullbasket?)......created alot of problems for the german road and rail network during the summer of 1944.

stuart

[Lkefct]

Allied Bomber barons have been preaching strategic bombing ever since they got the idea back in WW1. IT is going to take a lot more failure then 6 months worth of heavy losses. Unless the entire bomber force for the US and UK are wipped out, they are going to change tactics several times first. For no other reaosn that it will take at least that long to retool the factories. Also, given the ranges necessary for allied bombers to operate in some of the other roles (maritime, in asia, etc), I don't think going to medium bombers is an option. There are a lot of roles that going to a 2 engine configuaration is not going to work. Also, going back to the production, there is no such thing as a small production line for heavy bombers. You go all the way or not at all really. That is not strictly true, but given the scale on which the US and allies are operating, at least the b24 needs to stay in production. The b29 has had a huge amount of development time invested, so they are going to build them too.

Bombing brought Germany to her knees for a couple of reasons. First is that it added additonal stresses to a war time economy that it could not take. Inustrial production was never hurt like the bomber barons had hoped. IT did manage to distrupt the germans efforts to improve their efforts, but it never hurt it that badly. The primary thing that it did was force the Luftwaffe into battle to be destroyed, and assured air superiority. This was occuring even before the introduction of the P51, but then accelerated into overdrive once the long range escorts kicked in. Once air superiority was attained, both tactical and strategic operations became notably more effective, and it completely robbed the Germans of the strategic and tactical initative. The reaminder of the war, the allies where much more successful by forcing the germans to react to them rather then let the heavy armor get concentrated against them. Instead pockets of german armor are dispearsed along a braod front to match the allied attacks along a broad front. The germans inflicted many tactical defeats along the way, but the strategic picture was never in doubt.

If the allies go over to all tactical bombing, they will never be able to achieve the level of air superiority that they achieved by the massive attrition that the strategic bombing campaign achieved. The germans can always pick their spots to oppose the allies. Air superiority was never as complete on the eastern front as it was on the west, largely for this reason. Sure the western allies have a lot more planes, but tactical bombing is going to lose a lot to flak, and the german fighter arm with all those rockets is still going to knock a lot of the mediums down.

[Lars]

Two very interesting pieces of info which I´ve just read:

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!!

Add to that, that an American post-war study revealed that a German proximity fuse would have meant 3.4 more bomber losses.

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. However, the fuse couldn´t be tested until April 1945 in a major trial during a bomber attack in the Munich area. 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 at an average flying altitude of 25,000 feet and a speed of 250 miles per hour had the Germans developed a proximity fuse. Instead of a loss ratio of 11 bombers per 1,000, the loss ratio would have been 37 bombers per 1,000."

Clearly there was plenty of room for improvement for the conventional German flak in WWII!

[T. A. Gardner]

There may have been room for improvement but, it wasn't going to improve much. And, it certainly wasn't going to triple the effectiveness by any means.

Looking more generally at the whole use of AAA problem, we find:

The advantages of flak are: It is cheaper than missiles or aircraft in terms of equipment procurement and crew costs. It requires a relatively low level of skill for the majority of the crew (ie., they are cheap to train and quickly proficent in its use). Its combat readiness is not easily degraded and, its effect is readily calculable.

The disadvantages are: Short range. This presents two seperate problems. First, flak can only defend a local target to its location. Second, it quickly reaches maximum density meaning that only so many guns can be realistically applied against a target. The attacker can often avoid flak by maneuver or route selection. Flak is relatively static.

To increase the effectiveness of a flak gun one can: Raise the muzzle velocity / velocity of the round in flight. There is a practical maximum of about 4500 to 5000 fps involved here. Raise the rate of fire. The mechanical limit for heavier guns appears to be right around 100 rpm. Increase the effective burst diamter. This is limited by shell size, explosives available and, materials that the shell can be made from. Add better fire control. This includes better fuzing.
The attacker can decrease its direct effectiveness by: Maneuver. A target that is not maintaining a steady course is harder to hit. Flying higher. Longer shell flight times decreases the accuracy of prediction and gives the attacker more time to maneuver. Flying faster. Again, this decreases prediction accuracy. Use counter-measures against the fire control (eg., jam radar, blind optics etc.).
The attacker also has the option to ignore targets too heavily defended in favor of ones with weaker defenses. An attacker can also switch to stand-off weapons that make going through the flak with the attacking aircraft unnecessary. An attacker can also try to "roll back" defenses by attacking the flak positions directly either supressing or destroying them.

As an example, if we assume the following about a flak gun and its target:

Flak gun: Vert range = 40,000 yards Horz range = 80,000 yaards (per Tartaglia's rule for cubic functions where an approximation can be easily made that the horizontal range is about double the vertical). MV is 3000 fps. RoF = 20 rpm. Pk = 1 plane per 600 rounds fired.
Target: A steadily flying aircraft at 250 knots (or 8,333 yards per minute) flying at various altitudes per below:

For the aircraft at 25,000 feet the Pk is .43 per gun with a maximum slant range of 54,000 yards and firing time of 13 minutes. Shell time of flight is about 60 seconds.

If the aircraft goes to 30,000 feet the Pk falls to .3 per gun firing time to 10 minutes and maximum slant range about 42,000 yards with a shell flight time of about 55 seconds.

At 35,000 feet the Pk falls to .14.

Reducto absurdum: Taking flak to its extreme:

IN the late 40's systems were developed for AA defnese that took these weapons to almost absurd levels of cost and complexity in the quest for a more effective system. One extreme example is Britain's Green Mace AA gun. This system was under development through the late 1950's before being abandoned. The final version was to be a 5" (127mm) water-cooled, automatic loading gun firing 96 rpm. A fin stabilized discarding sabot round with proxmity fuzing was to be used to increase the velocity of the rounds and the likelyhood of a hit. The entire mount weighed over 30 tons.
The US and Sweden (Bofors) among others, attempted similar systems on a smaller scale with 50 to 75mm guns. Events and the development of reliable SAMs put an overdue end to such guns by 1960.

[Lars]

Regarding the R4M rocket. The German version of Wikipedia has better specs for the rocket. It specifies that the rocket overall weighted 5 kilos and then goes on to specify what those 5 kilos were made up of (like Warhead =1 kilo):

Allgemeines:

* Entwurf/Konstruktion: Rheinmetall
* Länge: 66 cm
* Durchmesser: 5,5 cm
* Geschwindigkeit: 1850 bis 2200 km/h
* Brenndauer: ca. 3,5 sek
* Reichweite: 2 bis 2,25 km

Gewicht:

* Gesamt: 5 kg
* Hülle u. Technik: 1,5 kg
* Treibladung: 2,5 kg
* Sprengkopf: 1 kg

Oddly enough the cost of each salvo of R4M went up from 500 RM in 1944 to 750 RM in 1945:

Kosten:

* Die Kosten der Rakete lagen pro 2 Batterien 1944 bei ca. 500 Reichsmark, 1945 bei ca. 750 Reichsmark.

[Von Schadewald]

Wikipedia http://en.wikipedia.org/wiki/88mm states:

"There were complaints that, due to the apparent ineffectiveness of anti-aircraft defences as a whole, the guns should be transferred from air defence units to anti-tank duties, but this politically unpopular move was never made."

WI the Germans suddenly assigned 50%, or even 25% of their thosands of Reich-based 88mm flak guns in mid 1944 for pak and artillery use.

Could they do it? Did they have the transport? Would the flak crews, usually 3rd liners or flak-hilfer youth, be up to front line ground warfare?

A few less Allied bombers will be shot down.

But could such an increase of guns, especially on the Eastern front actually slow down the Russians, or even bleed their tank corps white?

Or no real difference?

Was shortage of AT guns ever an issue for the Germans in OTL, even in 1945?

[Lkefct]

The germans where always short of AT guns. That is not even a point for debate. Even relatievely fresh units could have used more AT guns, and the units that have been in the lines where very short of AT guns. This is especially true of the larger caliber guns, like the 88mm guns. The probelm doesn't lie in the lack of desire to use the guns farther forward.

How would you tow all the guns? Gernany is crtically short of all forms of motor transport, but especially the prime movers used to tow the big flak guns. The nice thing about using them in the Flak role defending Germany is that they can be left realteively static or moved via rail. If you look at German Pak losses, they conincide with the major german retreats, not necessarily the major german counter attacks. Since Germans use their Pak guns in cooperation with tanks and assualt guns, this certainly suggests that the problem is transport. Guns are left behind/destroyed/captured because they can't get out of the way. Similar patterns are visible with damaged tanks. Gemran infantry units get somewhat weaker and weaker due to infantry losses, but they become much less combat effective since their guns represent a large proportion of their total firepower.

Also, just having them in forward units don't mean they will be as effective as their numbers suggest. Many of the combat losses come due to artillery fire. THe Allies have tons of extra guns to shoot up the flak units once they dig in. What few survive will probably be tremendously effective. During certain periods Mostly the 1942-43 period in the east, and the western desert, a small number of guns can cause a huge casualty lists for the allies, but MOST of the guns are likly to be blown away by the allied artillery barrage that is used to soften things up.

If the Soviets know the Germans have put more guns in the line, they will probably just lengthen the bombardment accordinigly. The big 88 Flak guns are tough to conceal and entrench, so they will not be suprised by too many of them. Artillery is the Soviets best attacking arm and causes most of the casualties to the germans. Soviet artilleryt can bring much more firepower to bear, so in a way, this would be a good thing for them. It ties the germans to the front and keeps them under the Soviet guns, chewing them up faster. The small increase in the number of guns strengthens the defense and allows them to inflict more losses, but then there will be fewer guns in Germany so things get easier at the end. I don't think there is any reason to think that the Russians would be bled white. If anything, the heavier losses to the infantry and guns might allow the front to collapse sooner.