WWII Tactical AAA

[Al]

Is there an available study somewhere on the effectiveness of WWII Tactical AAA; i.e., the weapons usually found mounted on half-tracks?

 

Thanks in advance.

[Tony Williams]

Some quotes from my book 'Rapid Fire: the Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces':

 

"The evaluation of heavy machine guns was rather confused. They had proved largely ineffective in the AA role. An American analysis based on the last year of the war showed that over 50,000 .50" rounds were fired for every aircraft brought down, compared with 500 Bofors rounds; that is, almost two hours of continuous firing per gun, compared with four minutes."

 

and:

 

"Curiously, the British Army showed little interest in light cannon, rapidly abandoning the various 20mm guns for improved models of 40mm Bofors. This view was probably influenced by operational research into the relative effectiveness of the 20mm Oerlikon and 40mm Bofors in dealing with low-flying coastal raiders. It was noted that these were not usually spotted until 1,500 yards (1,370m) away, so the Bofors could not use its range advantage. Engagement times were only about 13 seconds (from first sighting the target to the last shot) and the Bofors only had time to fire seven or eight rounds to the Oerlikon's 50. Even so, in most circumstances the Bofors was more effective.

 

Calculations were made about the probability of success (immediate break-off, or eventual crash) against a Junkers 88. Using simple sights only, the Oerlikon's chances were estimated at 3% against a crossing target, 12% against one approaching head-on; the Bofors' 18% and 20% respectively. With more advanced sights, performance was much better. Using predictor control, the Bofors' success rate rose to 35% and 39%. The addition of a Triple Gyro sight had an even more dramatic effect on the Oerlikon's performance – to 17% and an astonishing 76% respectively."

 

Tony Williams: Military gun and ammunition website and discussion forum

[Chris Werb]

Tony, I just finished a book on Anti Aircraft Command 1939-55 The Other Forgotten Army by Anthony J. Cooper. He mentions some 40mm being replaced by multiple 20mm during the low-level hit and run phase of attacks on UK coastal towns in 1943. These were deemed more effective due to the lesser amount of warning time you got with an incoming single engined plane approaching at low level. Presumably that was before the operational analysis you mention was undertaken.

 

Have you got any detail on how those American figures were arrived at? My only experience of shooting at aerial targets is clays and birds, but we have several people on the island that effectively wing shoot ducks with .22 long rifles (this started here long ago due to .22LR ammo being much cheaper than shotgun). I think clays were part of the training given to US AA gunners along (air powered BB machine guns were also used to train air gunners).

 

I think the massive number of rounds may be partly due to the fact that the .50s were fired by personnel that weren't specialised or trained sufficiently in AA fire or were firing for deterrent purposes rather than with any real hope of hitting.

[Yama]

Don't know any figures, but German low level AAA with their 20mm and 37mm guns were highly respected; when Finns and Germans turned to each other in 1944, FAF immediately noted high effectiveness of German AAA and losses were heavy considering low amount of sorties. Similarly, I understand that low-level Flak took a heavy toll amongst Allied fighter-bombers right to the end of war.

[Paul Lakowski]

I seem to remember being told of testing the poor state of RN ship flak . A target was towed around the ships for ages and the ships were never able to hit this (?)

 

Any one ever heard any more details on this test.

[JOE BRENNAN]

An American analysis based on the last year of the war showed that over 50,000 .50" rounds were fired for every aircraft brought down, compared with 500 Bofors rounds; that is, almost two hours of continuous firing per gun, compared with four minutes."

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I wonder when the US Army would have fired large multiples of 50k rounds at airplanes from the ground in actual combat late in WWII to get a good statistical sample. Anyway the USN concluded .50 was a pretty useless AA caliber early in the war; although it's not quite the same situation defending a high value target like a ship, and when a .50 doesn't really have other roles (in a WWII shipboard setting) whereas it does on land. The US quad .50's were effective ground weapons in WWII, then especially so in Korea (and a keystone of the final series of French positions at Dien Bien Phu was a couple of towed lightweight quad .50's, M55). Though you can shoot 40mm at ground forces too, the quad .50 seems to have built a special reputation for that use, with some AA capability "for free" (more or less).

 

20mm, even with on-mount lead computing sight as std later in war was judged mainly useless on ship by 1945. When those started firing against a kamikaze attacking DD's off Okinawa it was said to be the signal to shut down the blowers to the engine room to avoid injesting flame when the plane hit.

 

But again depends on the threat, whether attrition/distraction of the enemy planes is sufficient, or they must be stopped each time, and what special diversion of resources the AA gun represents. For another example The DShK in Korea and Vietnam has to be judged a highly cost effective multipurpose incl AA weapon, I think.

 

Joe

Edited June 30, 2005 by JOE BRENNAN

[gnocci]

The consensus between Il-2 pilots seems to be that in the first half of the war, the main danger were enemy fighters. In the second half, the risk from fighters fell waaay down, while AAA, specially medium caliber (usually referred as "oerlicons"), rose waaaay up.

[Simon Tan]

Al - I assume you mean the M15 and M16 MGMCs issued to SP Anti Aircraft Autoweapons (AAA) units? As some posters have already pointed out, the .50 BMG was a pretty poor chambering against aircraft. While it is effective in terms of ballistic performance, it's lethality was very poor against the German attack aircraft of the day such as the Fw 190G. Thus while it might riddle an aircraft and cause it to abort, it simply lacked the wallop to knock them out the sky.

The M16 and M55 Maxson mounts were actually far better employed in ground fire and they earned a ferocious reputation for this.

The M15 and M15A1s employed a pair of .50s matched with a 37mm M1 gun. The latter was significantly less capable than the L60 Bofors. In the pacific they extemporised a Bofors onto the M15 as the M15 Special.

 

Indeed later war ground attack aircraft were very robust and heavily armoured. The Germans found that their 20mm Flak 30/38s (Solothurns rather than Oerlikons) were increasingly ineffectual against aircraft like the Typhoon and Thunderbolt. Even the Falkvierling quads were not considered to be adequate, which is why they went to the 37mm FlaK 43 as their 'desired' late war light AA piece. It would replace the Vierling on the MkIV Flakpanzers on the Ostwind and it was the standard armament for the Mobelwagen (Tamiya's 20 year gaffe not withstand). The FlaK 43 combined a high cyclic rate with the hiting power of the 37mm round of the Flak 36 and was a serious threat at low-altitiude.

 

The Germans however ran into increasing production difficulties with their highly engineered Refleksvisier (reflex gun sights) and went to the simpler Flakvizer ring type sights, which were a retrograde step but essentially what everyone else was running.

 

The measure of the failure of both the .50 and 37mm M1 can be measured by the fact that they were replaced at the war's end by the M19 MGMC mounting a pair of 40mm L60 Bofors. The end of the war cut into the reequipment process and resulted in hybrid M16 and M19 units fighting in the Korean war. Both proved exceptionally effective at breaking up infantry attacks and would play crucial roles in battles like Chipyong'yi (I can't spell these things)

 

Simon

[CaptLuke]

Al - I assume you mean the M15 and M16 MGMCs issued to SP Anti Aircraft Autoweapons (AAA) units? As some posters have already pointed out, the .50 BMG was a pretty poor chambering against aircraft. While it is effective in terms of ballistic performance, it's lethality was very poor against the German attack aircraft of the day such as the Fw 190G. Thus while it might riddle an aircraft and cause it to abort, it simply lacked the wallop to knock them out the sky.

 

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I subscribe to the theory that the purpose of AAA (like bomber defensive armament) is just to make the enemy planes fail to accomplish their mission, not to shoot them down. If a plane takes a couple .50 hits, breaks off the attack and returns to base, the AAA wins.

 

Also, this is the same .50 that, on US planes, hacked FW190s out of the sky in considerable numbers, so I'd be careful about lethality assumptions.

 

Ballistically, the .50 was probably the equivalent of the 20mm, which also required multiple mountings, preferably powered, to be effective.

 

The measure of the failure of both the .50 and 37mm M1 can be measured by the fact that they were replaced at the war's end by the M19 MGMC mounting a pair of 40mm L60 Bofors.

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There were an interesting variety of AAA projects that never made it with the US. , including IIRC a quad .60 turret on the M24 chassis. Late war the Germans were putting 15mm MG151s on half tracks in triple mountings so, while certainly their preference was for 30mm and up, even the Germans thought .50/.60 still had something to offer.

[Paul Lakowski]

Also, this is the same .50 that, on US planes, hacked FW190s out of the sky in considerable numbers, so I'd be careful about lethality assumptions.

 

Ballistically, the .50 was probably the equivalent of the 20mm, which also required multiple mountings, preferably powered, to be effective.

There were an interesting variety of AAA projects that never made it with the US. , including IIRC a quad .60 turret on the M24 chassis.  Late war the Germans were putting 15mm MG151s on half tracks in triple mountings so, while certainly their preference was for 30mm and up, even the Germans thought .50/.60 still had something to offer.

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I thought the whole idea of the gradual movement from MG to Cannons in fighter aircraft, was due to the inadequate killing power of machine guns. A single hit from a 30mm API, could cut a fighter in half.....Besides isn't the MG151 a 20mm cannon?

 

RE Heavy Flak, I read somewere that in 1943 roughly 3500 x heavy flak shells [88/105mm] were required to 'statistically' bring down a 'plane' flying over Germany.

[ShotMagnet]

I thought the whole idea of the gradual movement from MG to Cannons in fighter aircraft, was due to the inadequate killing power of machine guns. A single hit from a 30mm API, could cut a fighter in half.....

 

Not necessarily, considered in terms of fire-volume. Two or three cannon will certainly shred whatever they hit, but they have to hit; whereas 8 MG mounted in two wings will provide a pilot with a better chance of scoring at least one hit and probably doing something debilitating in the process.

 

To some degree size matters; British .303 MG had a hard time dealing with ME-109s, while the cannon from -109s did just fine against Spits and 'Canes. Keep the number of guns the same, though, and bump the size to .50 cal, and it's a different story. .303 is rifle ammo, .50 is not.

 

As aircraft became better armored the need to hit them harder became apparent, and eventually obviated the MG. Note however that in Korea Sabre pilots flew agains cannon-armed MiGs and in the final tally outscored the MiGs. Some Sabers were armed with cannon, but some were armed with MG.

 

Gun caliber certainly plays a role, so does the quality of pilot and/or plane.

 

 

...isn't the MG151 a 20mm cannon?

There are apparently two weapons with the MG 151 designator. One is the MG 151/15, the other is the MG 151/20. Both are cannon, but one is a 15mm weapon and the other is a 20mm weapon.

 

 

 

Shot

[Tony Williams]

Two or three cannon will certainly shred whatever they hit, but they have to hit; whereas 8 MG mounted in two wings will provide a pilot with a better chance of scoring at least one hit and probably doing something debilitating in the process.

 

The USN, which used both the .50 and the 20mm in aircraft, reckoned that the 20mm was about three times as effective as the .50. So the usual RAF quartet of 20mm was twice as effective as the usual USAAF fit of six .50s.

 

As aircraft became better armored the need to hit them harder became apparent, and eventually obviated the MG. Note however that in Korea Sabre pilots flew agains cannon-armed MiGs and in the final tally outscored the MiGs. Some Sabers were armed with cannon, but some were armed with MG.

The superior performance of the Sabre was despite rather than because of its armament (although the MiG-15 was no better in that respect, as its armament was optimised for use against heavy bombers). Nearly all of the Sabres were equipped with .50s, but late in the Korean War the USAF combat-tested Sabres armed with 20mm cannon, and the result was such that they immediately switched to 20mm for all new planes thereafter. At the same time, the rest of the world moved up to 30mm...

 

There are apparently two weapons with the MG 151 designator. One is the MG 151/15, the other is the MG 151/20. Both are cannon, but one is a 15mm weapon and the other is a 20mm weapon.

 

Actually, according to the Germans, they were both machine guns rather than cannon, whgich is why they have the MG rather than MK prefix.

 

If you want to learn about WW2 fighter armament, read this: http://www.quarry.nildram.co.uk/WW2guneffect.htm

 

Tony Williams: Military gun and ammunition website and discussion forum

[Chris Werb]

Al - I assume you mean the M15 and M16 MGMCs issued to SP Anti Aircraft Autoweapons (AAA) units?

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That's the crux of the matter. They would have been a small percentage of the total number of 0.50s that could have been trained at aircraft. The quad fifty could also be used dismounted - and post war often was. Many were used in Vietnam. I don't think that was the case with the 37+2 0.50s mount (which served as late as Korea)

[Simon Tan]

The MG151 Drillings on the SdKfZ 251/21 were a naval mounting that was impressed into service on a simple free pedestal mount. While on paper they seem impressive, in reality the extremely cramped arrangements and solitary gunner made it a rather poor AA weapon. They were however better than the alternative, which for the gepanzert battalions was nothing heavier than a MG42 on the stern AA pintle.

 

Despite the 20mm calibre, the MG151 was in no way comaprable to the much larger FlaK 38 in terms of either ballsitic performance or lethality. The experience of Normandy pretty much drove the Germans to the conclusion that any AA was better than no AA.

 

The SdKfz 251 wasn't suited to mounting AAA due to the inwards slope of the upper armoured surfaces. The Germans did however make extensive use of the lighter DEMAG SdKfz 10/4 and heavier Hanomag SdKfz 7 as SP FlaK guns but these had unprotected flatbeds onto whicht he guns were mounted. The SdKfZ251/17 FLaK SPW was not very successful. The 'famous' Luftwaffe version had the flank armour hinged to open out to enable low-angle fire but there were precious few of these. The more common solution was a hybrid Kwk30 with FlaK 38 barrel on a pedestal, somewhat simialr to the Hanglafettes of the Radpanzer. This suffered from many of the problems that were to plague the Drillings.

 

The .60 HMG never went anywhere. It lacked the punch of 20mm cannon and the extra ballsitic eprformance just didn't make all that much difference. In fact the only >.50 cal weapon to have any success has been the 14.5mm KPV. It wasn't adequate by any means and was supplanted in the 60s by the iconic ZU-23.

 

Chris...you're thinking of the M55 Maxson ground mount. It goes on a trailer. I don' think the M16 units routinely dismounted the guns but I believe that M16 Maxson mounts may have been converted into M55s. These would wind up on 'gun trucks' in VN.

[Rich]

Chris...you're thinking of the M55 Maxson ground mount. It goes on a trailer. I don' think the M16 units routinely dismounted the guns but I believe that M16 Maxson mounts may have been converted into M55s.

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And of course the other way around. Prior to 6 June 1944 US Army Ordnance mounted 321 M55 mounts onto spare halftracks in England, enabling them to equip one SP platoon in each battery in nearly every AAA Automatic Weapons (Mobile) Battalion in the theater. My Dad commanded one of those platoons in Battery A, 537th AAA Battalion. I think those were eventually the source of the M55 mounts "converted" from M16, since the trailer minus its wheels had been simply bolted into place.

[Simon Tan]

And of course the other way around. Prior to 6 June 1944 US Army Ordnance mounted 321 M55 mounts onto spare halftracks in England, enabling them to equip one SP platoon in each battery in nearly every AAA Automatic Weapons (Mobile) Battalion in the theater. My Dad commanded one of those platoons in Battery A, 537th AAA Battalion. I think those were eventually the source of the M55 mounts "converted" from M16, since the trailer minus its wheels had been simply bolted into place.

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This is whacky because around the same time, the British Army was busy stripping >1,000 M14 MGMCs (twin .50 Maxsons) of their mounts to make into regualr HTs! They had little enough need for these since they were even busy disestablishing SP LAA.

 

Was the 537th a 'real' SP unit?...or extemporised? I always though the AAAs attached to Infantry divisions kept M55s and Bofors guns.

[tomcat_1974]

Any data for the Russian SPAAG in ww2? I just know that they where feared by CAS pilots of LuftWaffe and RRAF that flew HS129B's.

[Al]

Thaks for all the great info guys. This is really helpful.

 

Couple of other points. I have heard that since the threat from the Luftwaffe was low, that AAA units were used to provide replacements for the infantry. Rather than just sending men, were any of these AAA units "broken up" & parceled out to line units? For instance, assigning a AAA battery to infantry battalions so they could be used in the ground support role?

[Rich]

This is whacky because around the same time, the British Army was busy stripping >1,000 M14 MGMCs (twin .50 Maxsons) of their mounts to make into regualr HTs! They had little enough need for these since they were even busy disestablishing SP LAA.

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Why was it "whacky" Simon? Those were British Army Lend-Lease vehicles, not US Army vehicles? And by this time the BA was pretty well equipped for the invasion with 20mm and 40mm SP AA, I can give you details if you are interested.

 

 

Was the 537th a 'real' SP unit?...or extemporised? I always though the AAAs attached to Infantry divisions kept M55s and Bofors guns.

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Nope, it was a "Mobile" battalion, not SP. Re-examining may stuff I find that the Automatic Weapons Battalions were organized as:

 

SP - four batteries, each of four platoons, two with 4 M15A1 each and two with 4 M16 or M17 each.

 

Mobile Standard TO&E - four batteries, each of four platoons, two with 4 40mm towed each and two with 4 M51 MG carriages (M55 was actually intended as an airportable mount and was in limited supply in theater).

 

Mobile Modified TO&E - four batteries, each of four platoons, two with 4 40mm towed each and the other two with either 4 M51 each or 4 M17A1 each (the theater-modified M5 HT with and M51 bolted onto the rear). There was a lot of variation, the 537th had A Battery with two platoons of M17A1 (my Dad commanding one of them), B and C Battery were the same, but D Battery had .50 caliber AA MG M2A1 (water-cooled) on Mount M2A1.

 

Semi-Mobile, organized as per the Standard Mobile TO&E, but with fewer prime movers.

[John(txic)]

I seem to remember being told of testing the poor state of RN ship flak . A target was towed around the ships for ages and the ships were never able to hit this (?)

 

Any one ever heard any more details on this test.

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Yes - the famous incident involving the Queen Bee - apparently, the "dive" command was eventually given, to simulate being shot down!

 

I have seen this referred to in many books, so it is probably not an apochryphal tale; alas, I can give no references at the moment.

[Tony Williams]

Any data for the Russian SPAAG in ww2? I just know that they where feared by CAS pilots of LuftWaffe and RRAF that flew HS129B's.

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Apart from the 12.7mm DShK, which was the equivalent of the .50 M2, they used automatic cannon derived from Bofors designs, in 37mm and 25mm calibre. See the article on my website on 'Bofors Automatic Cannon'.

 

Tony Williams: Military gun and ammunition website and discussion forum

[Chris Werb]

Simon, post war the Dutch built a wide variety of fortifications as part of their Ijssellinie defence plan. Many of these structures used quad 50s. Those accessible by land (some were built into dams etc.) didn't have the quad mount permanently fitted - instead an AAHT would drive out and the gunners would take the mount off the HT and bolt it to a turntable inside the position. These vehicle gun mounts were apparently not the M55 with the tyres. The position even even had a sunken parking spot for the vehicle. Here is a model of one such position:

 

http://www.johannas-art.com/M16HT.jpg

 

I'm not suggesting this was routine in the ETO or that this happened in Korea or Vietnam. However, I'm sure that multiple mountings of all types would have been a small minority of 0.50s that would have been trained at attacking aircraft in most circumstances. Most would surely have been vehicle flex guns and single ground mounts. Some US Engineer units in england even put single water-cooled pedestal mounted fifties on the back of trucks.

 

AA Command was losing personnel and units from quite early in the war as the air threat diminished and other arms started to suffer personnel shortages. However, some SPAA was used in the Diver belt against flying bombs. Some SPAA tanks also made it to Normandy, although I believe some of the units that had the AA tanks left them behind during the subsequent advance. I'm sure Rich could clarify/debunk that though.

[Guest RuLavan]

Any data for the Russian SPAAG in ww2? I just know that they where feared by CAS pilots of LuftWaffe and RRAF that flew HS129B's.

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Except Dshk's was widely employed quad-mounted, liquid-cooled Maxim machineguns AA 7,62mm(.303). Together with Dshk's they officially claimed 512 aircraft kills. Typically, it takes 3 to 6 .50 hits to shoot down Bf -109 and 2-2,5 times more with .303.

[yak_v]

Any data for the Russian SPAAG in ww2? I just know that they where feared by CAS pilots of LuftWaffe and RRAF that flew HS129B's.

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Russians didn't have any SPAAGs in WWII. The only real SPAAG was rather unsuccessful ZSU-37 built on the basis of the T-70 light tank. Only 100 or so were built and they were not a success. Other than that there were some lend-lease halftracks with AA guns and improvised trucks with guns ranging from 7.62mm Maxim to 37mm 61-K.

 

Vladimir

[Risto Järnström]

Finland used the Swedish Landsverk Anti II SPAAGs which had a single 40 mm Bofors gun. Six of them were bought and they were used to protect the lone armoured brigade and managed to shoot down 11 aircraft and damage 7. Those were probably mostly Il-2s, but I don't know exact details. Pretty good score as they didn't lose any of their vehicles, but 4 men were KIA and 11 WIA. It was also very important that many air attacks were foiled and Shturmoviks didn't manage to destroy the armoured units. I think that Landsverk Anti II was probably the best SPAAG which participated in WWII. Of course the Swedes developed even better SPAAG in Lvkv fm/43. Some pictures and Swedish text can be found at :

http://www.pansarmuseet.se/lvkv43.htm