WWII Tactical AAA

[Rich]

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

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Yep, 100 M15 and 1,000 M17.

[ABNredleg]

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.

189439[/snapback]

 

It took place in 1937 when a Queen Bee drone flew straight and level around the entire Mediterranean Fleet at a stately 85 knots and wasn't hit by a single shell. The problem, of course, was not the weapons, but the fire control system - the British High Angle Control System was flawed in concept and design and RN AAA suffered as a result.

Edited July 2, 2005 by ABNredleg

[Waffenhammer]

It took place in 1937 when a Queen Bee drone flew straight and level around the entire Mediterranean Fleet at a stately 85 knots and wasn't hit by a single shell. The problem, of course, was not the weapons, but the fire control system - the British High Angle Control System was flawed in concept and design and RN AAA suffered as a result.

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My father-in-law was a radar operator aboard the USS Wright (CVL-49) late in the Korean War. He told a similar story of a drone flying unhit over the ship during excercises off Key West Fl. The gunnery officer thought it would be easier to hit if the drone was diving towards the ship!. The drone crashed into a gun tub, killing three, and the gunnery officer was taken off the ship that evening.

[Paul Lakowski]

It took place in 1937 when a Queen Bee drone flew straight and level around the entire Mediterranean Fleet at a stately 85 knots and wasn't hit by a single shell. The problem, of course, was not the weapons, but the fire control system - the British High Angle Control System was flawed in concept and design and RN AAA suffered as a result.

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Thanks for the link. Interesting they had radio controled plane back in the 1930s.

 

If this target paraded for an hour and on 'flak' type gun could do 12 RPM thats ~ 700 rounds per gun. They must have fired thosands of rounds without any results.

 

The german 1943 example of 3500 rounds per plane shot down over germany presumably was from 'grossbatterie' I wonder what kind of fire control directors they had back then? I gather by 1944 the figure had climbed to 35,000 rounds per plane shot down. I wonder what changed to result is such a change in results?

[JOE BRENNAN]

The german 1943 example of 3500 rounds per plane shot down over germany presumably was from 'grossbatterie' I wonder what kind of fire control directors they had back then? I gather by 1944 the figure had climbed to 35,000 rounds per plane shot down. I wonder what changed to result is such a change in results?

190471[/snapback]

"Flak" by Westermann is a pretty complete history of the flak arm. Rounds per kill varied a lot and he seems to admit that single undisputed figures even for a period of the war can't be certain. But some comparatives he gives are first 20 months of WWII: 2805 heavy and 5354 rounds of light flak per kill. Late 1943 4000 heavy and 6500 light. (Light presumably refers to national defense Luftwaffe light flak only).

 

He discusses what he says is often quoted 16,000 rounds per kill by 88mm in 1944. Among the reasons were basic gun v. plane performance; B-17's bombed from the edge of the Model 36-37's (always far the most common 88) effective envelope and were more common attackers in 1944 than previously. In contrast the relatively rare (never more than a small % of flak force) 128mm reqd 3,000 shells per kill in 1944. Also in 1944 degraded guns that needed barrel changes were more common, and Allied ECM continuously improved. For example by the fall of '44 most USAAF bombers had active jammers, before that pretty uncommon.

 

The Germans had a hi/lo flak mix where some batteries had no directors, were often captured weapons (like Soviet 85mm) and fired barrages w/o directors. But the more numerous standard batteries almost all had directors and fire control radars even by 1943; thereafter what level of ECCM upgrade against chaff and jammers made a difference.

 

For comparison to the 128mm ratio, USN 5" with VT in the same period had ratio's in the range of 60-240 rounds per kill for different conditions of range and day v. night engagements per Friedman. The ratio of VT to time fuze effectiveness was given as around 4 to 1. The naval gun targets were not directly comparable: easier to reach and employing less ECM (Japanese used no active jammers AFAIK, though did use chaff, and used passive receivers to approach along nulls in antenna radiation patterns at night, late war); OTOH typically smaller, faster and maneuvering less predictably.

 

Joe

Edited July 2, 2005 by JOE BRENNAN

[Geoff Winnington-Ball]

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?

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I know this happened to some of the Canadian units in 1944, but we were going through the Great Conscription Crisis at the time, and many infantry regiments were manning the line at half-strength. Reinforcements from other support units were culled as well, many only half-trained, which resulted in a noteable increase in the casualty rates afterwards.

 

Some of our other LAA units were kept intact for ground support roles; interestingly, the barrel replacement rate for 40mm Bofors became a critical issue when firing 'pepperpot' missions - according to Blackburn, sustained firing caused the barrels to bulge. Still, I suppose they felt that they were at least doing something useful.

 

My favourite Bofors story comes from Johnnie Johnson's WING LEADER... a single gun on forward airfield defence shot down a strafing ME-109 with one round... the gun corporal asked Johnson to verify the kill as he said his own commanding officer would never believe it! Johnson promised to do that, and supplied a case of beer for the gun crew...

[Paul in Qatar]

Is it true that early in WWII a single radar-directed shot destroyed a British bomber? I read (somewhere, Soldier of Fortune or a box of cereal) that this inspired Herr Goreign to claim no British bomber would ever attack the Fatherland.

[ABNredleg]

"Flak" by Westermann is a pretty complete history of the flak arm. Rounds per kill varied a lot and he seems to admit that single undisputed figures even for a period of the war can't be certain. But some comparatives he gives are first 20 months of WWII: 2805 heavy and 5354 rounds of light flak per kill. Late 1943 4000 heavy and 6500 light. (Light presumably refers to national defense Luftwaffe light flak only).

 

One of the more interesting things the Germans did was experiment with impact fuzes for their heavy flak guns. The theory behind this was that the chances of putting a time-fuzed shell close enough to damage an aircraft was almost the same as getting a direct hit, and by using impact fuzes you would eliminate any error created by the time fuze, as well as increasing the rate of fire and shortening the time between calculation and firing. The scientists crunched the numbers, which showed that theoretically the impact fuze was far more effective than time fuzes, and sought to convince the LW flak experts to do firing trials - during combat trials in Munich heavy flak batteries during one raid shot down 13 aircraft with an average expenditure of 370 rounds per shootdown. In late March the Luftwaffe ordered the heavy flak batteries to use nothing but impact fuzes, but by then it was too late to have any affect.

 

 

Source: "German Artillery of WW II" by Ian Hogg

Edited July 4, 2005 by ABNredleg

[Dan Robertson]

Thanks for the link. Interesting they had radio controled plane back in the 1930s.

 

The terminology of calling unmanned aircraft "drones" comes from this system. The aircraft with a the remote controller on board would be "queen bee", and the remotely controlled aircraft was the "drone".

 

What always amuses me is that the people around at the time couldn't see the woods for the trees and never though of attaching a bomb to the Drone and using it as an anti ship weapon.

[Chris Werb]

What always amuses me is that the people around at the time couldn't see the woods for the trees and never though of attaching a bomb to the Drone and using it as an anti ship weapon.

191208[/snapback]

 

Twenty years earlier, they had done exactly that!

 

In 1915, the Navy appointed both Sperry and Hewitt to its Naval Consulting Board, and Sperry, as chairman of the Board's Mines and Torpedoes Committee and a member (along with Hewitt) of its Aeronautics Committee, had little trouble gaining Navy approval and funding that October to continue developing what had come to be called an "aerial torpedo." The aerial torpedo program was broken into two phases, the first to develop a gyrostabilized, bomb-carrying drone with a distance gear (i.e., a preprogrammed version), followed by the addition of radio controls for directing the torpedo from an accompanying airplane (i.e., a controllable version). The Navy's concept of operations was to employ the torpedoes against German U-boat bases and munitions factories from distances of up to 100 miles. Flight tests began in 1916 using Curtiss N-9 seaplanes with safety pilots in them to perform the takeoffs and landings, and by November, 30-mile flights with accuracy errors of 2 miles (400 feet per mile flown) were being achieved.

 

[snip!]

 

During these same years in Britain, the Royal Aircraft Establishment was also developing a cruise missile, working up to flight ranges of 300 miles before beginning tests with live warheads from a RAF station near Basrah in present-day Iraq. These flights became the first of the numerous cruise missiles to traverse this terrain in the decades to come.

 

Target drones were introduced in the 1930s in both the U.S. and in Britain as a spin-off of these early cruise missile efforts.

 

Much more here:

 

http://www.uavforum.com/library/defnews.doc

 

In WW-2 the US deployed bomb carrying drones in the Pacific with some success:

 

http://www.stagone.org/

[Argus]

IIRC the radio control gear used on the Queen Bee was actually based on GPO technology, from their automatic telephone exchanges. The controler had a telephone dial with each number replaced by a command; dive, climb, left turn, right turn etc. The rear cockpit of the Tiger Moth had a dial (the kit filled the forward cockpit) as did the ground stations, and it was a normal testing procedure for a pilot to fly a sortie from the rear cockpit by dialing the commands and letting the gyros do their thing.

 

Fitting a bomb was thought of, in fact the idea was raised during WWI, and it had been one of the factors driving the whole program from the RAF point of view. But the cost of an airframe, compared to the limited payload, range and accuracy just didn't work. Some thought was given to an incenduary raider, that was basicly a motorised cluster bomb, but the cities targeted were too distant for the existing DH82a based drone, and anything more sophistocated again lost on a cost benifit analysis.

 

It's been a long time since I read this and I can'tn remember the title, so I might be a bit off on detail, but I'm pretty confident about the overall picture.

 

shane

[istvan47]

Joe, perhaps the statistics about the 0.50 cal AA ammo expendure vs downed targets was mainly based on Tunisy campaign, where it was said that around 100 enemies were shot down by light AA units of US Army ( who knows if there were included the M2 of the AFVs like HT and tanks? I think only quad amount!)

[KingSargent]

It took place in 1937 when a Queen Bee drone flew straight and level around the entire Mediterranean Fleet at a stately 85 knots and wasn't hit by a single shell. The problem, of course, was not the weapons, but the fire control system - the British High Angle Control System was flawed in concept and design and RN AAA suffered as a result.

190374[/snapback]

Not that RN AAA direction was any good (until they just adopted the US Mk 37 and fitted it with Brit radar), but to be fair the director systems couldn't "dumb down" enough to cope with an 85 mph airplane. Not even the Stringbag was that slow.

 

In the same general frame, I have seen it said that the reason Bismarck couldn't hit the attacking Swordfish was that their directors couldn't cope with a plane that slow. I have no idea how they would know this.

[FormerBlue]

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.

Effective at what? Causing damage? Hitting? The two aren't mutually inclusive.

 

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.

In reviewing the .50s versus the Soviet Mig armament, the USAF determined that the cannon caused more damage when it hit. That's in line with your statement above. But there is a caveat.

 

They found that the use of the .50s meant there was less arc. Easier for the gunsite in the F-86 to compute. So the .50s were more effective at hitting. Until the velocity is raised on cannon in which case the cannon become superior. I gathered that the Soviet cannon were kind of arcy. Slow firing too. At a leasurely 600rpm the M2, x 6, is giving 3600rpm.

 

At the same time, the rest of the world moved up to 30mm...

Yes well that whole arc thing and speed thing still applies. US aircraft are still using 20mm. Seems to work.

 

The M39 was developed by the Springfield Armory, based on the World War II-era design of the German Mauser MG 213C, a 30 mm cannon developed for the Luftwaffe, but not used in combat. The same design inspired the British ADEN cannon and the French DEFA, but American designers chose a smaller 20mm round to increase the weapon's rate of fire and muzzle velocity at the expense of hitting power.

So I don't think the European move to 30mm is "correct" as much as it just satisfies their desire for a different effect.

 

Yes, cannon are better. But they have to fire fast and flat in US usage.

 

To get back to the thread. It wasn't a question of 40mm versus .50. US AAA was in three tiers. At range the 90mm was supposed to do the work. As the aircraft got closer the 40mm kicked in instead of the 90mm. When they were real close the .50s took over. Something to do with the 40mm not being effective up close for some reason. Could be speed of traverse. I could look it up but it takes time.

Edited August 14, 2005 by FormerBlue

[Richard Lindquist]

US Army Active AAA Bns:

 

31 Dec 42-391

30 Jun 43-547

31 Dec 43-557

30 Jun 44-479

31 Dec 44-347

31 Mar 45-331

[Tony Williams]

Effective at what?  Causing damage?  Hitting?  The two aren't mutually inclusive.

Causing damage, certainly - but that includes both hitting and destructiveness. In fact, the ballistics of the 20mm Hispano and the .50 were close enough for this not to be an issue at normal combat distances.

 

They found that the use of the .50s meant there was less arc.  Easier for the gunsite in the F-86 to compute.  So the .50s were more effective at hitting. 

The USAAF was obsessive about velocity in WW2. Yes, it improves hit probability but if you lose a lot of destructiveness then there's not much point. It is interesting that other air forces, with a choice between high-velocity HMGs like the .50 or cannon, invariably chose the cannon as a result of their combat experience.

 

Yes well that whole arc thing and speed thing still applies.  US aircraft are still using 20mm.  Seems to work. 

It isn't really an issue any more, guns have been become so unimportant in air combat..

 

TW

Edited August 14, 2005 by Tony Williams

[Chris Werb]

It is interesting that other air forces, with a choice between high-velocity HMGs like the .50 or cannon, invariably chose the cannon as a result of their combat experience.

 

Surely some of the 20mm cannon had velocities not unlike a 0.50 Browning? The Hispano used on RAF fighters fired a fairly high velocity round IIRC.

[FormerBlue]

It isn't really an issue any more, guns have been become so unimportant in air combat..

 

TW

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You do realize that is why the F-4 was designed without one right?

[CaptLuke]

Causing damage, certainly - but that includes both hitting and destructiveness. In fact, the ballistics of the 20mm Hispano and the .50 were close enough for this not to be an issue at normal combat distances.

The USAAF was obsessive about velocity in WW2. Yes, it improves hit probability but if you lose a lot of destructiveness then there's not much point. It is interesting that other air forces, with a choice between high-velocity HMGs like the .50 or cannon, invariably chose the cannon as a result of their combat experience.

It isn't really an issue any more, guns have been become so unimportant in air combat..

 

TW

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For hitting, a short time of flight and a high rate of fire are key. The Hispano had good velocity but IIRC the M3 .50 kept a substantial rate of fire advantage.

 

As for hitting power, two comments:

 

1. The US had issues with the .50 even in WWII and bungled a .60 development program that would have yielded something like the MG151/15 so even within the "Heavy Machine Gun" philosophy, there was recognition that the .50 was out of steam by 1945.

 

2. It's purely speculative, but I believe the US was the only air force that never faced a bombing offensive [the arguable exception being Japanese Betties, which may have been the most flammable combat aircraft in WWII] and that this goes a long way towards explaining why they stuck with the .50

USAAF night fighters, which were designed to engage bombers from the start, carried 20mm armament.

[DKTanker]

It isn't really an issue any more, guns have been become so unimportant in air combat..

TW

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Until the guy you're trying to shoot down with a missle has as good or better stealth technology than do you. You might be wishing you had a cannon or two after watching your missles fly harmlessly by the guy who's now shooting his cannons at you.

[FormerBlue]

Until the guy you're trying to shoot down with a missle has as good or better stealth technology than do you.  You might be wishing you had a cannon or two after watching your missles fly harmlessly by the guy who's now shooting his cannons at you.

207196[/snapback]

Planes don't carry a lot of missiles. What do you do if you run out in a furball? Opening the canopy and tossing your thermos at somebody is considered bad form. I suppose you could bomb them with your centerline if you hadn't ejected it before the fight.

 

The last real fighter on fighter of any real amounts that the US had was VN. I think it was 75% of kills were hitting the other guy with chunks of metal.

[Chris Werb]

The last real fighter on fighter of any real amounts that the US had was VN.  I think it was 75% of kills were hitting the other guy with chunks of metal.

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Missiles, fire control, sensors and command and control have come a long way since 1972. You've pretty much mastered the art of shooting down enemy fighters before they get within gun range. Gun kills have been exceptional for a long time. How many of the 80 or so kills the Israelis inflict on the Syrians in 1982 were gun? How many air to air gun kills (against fixed wing aircraft) did the US make in 1991?

[FormerBlue]

Missiles, fire control, sensors and command and control have come a long way since 1972.  You've pretty much mastered the art of shooting down enemy fighters before they get within gun range.  Gun kills have been exceptional for a long time. How many of the 80 or so kills the Israelis inflict on the Syrians in 1982 were gun?  How many air to air gun kills (against fixed wing aircraft) did the US make in 1991?

207210[/snapback]

On 17 January 1991, a USAF EF-111 was credited with a kill against an Iraqi Dassault-Breguet Mirage F1, which it managed to maneuver into the ground, making it the first and only F-111 to achieve an aerial victory over another aircraft.

Lack of thermos and cannon perhaps?

[Chris Werb]

Lack of thermos and cannon perhaps?

207215[/snapback]

 

IIRC EF-111s weren't equipped with missiles either.

[Tony Williams]

Surely some of the 20mm cannon had velocities not unlike a 0.50 Browning?  The Hispano used on RAF fighters fired a fairly high velocity round IIRC.

207147[/snapback]

 

Yes, but the Luftwaffe switched from their high-velocity 15mm MG 151 to the lower-velocity 20mm version because it was more destructive. And the Russians preferred the 20mm ShVAK over the 12.7mm UB despite the fact that it was heavier, slower-firing and had a lower velocity.

 

And in both cases, the need to deal with heavy bombers was not an issue: the Luftwaffe's 15 to 20mm switch took place in 1941.

 

Tony Williams: Military gun and ammunition website and discussion forum