WWII Tactical AAA

[Lev]

I think the idea that the US quad .50 is a special case is also supported by the lack of upgrade kits for all the Warsaw Pact unpowered quad 12.7mm and 14.5mm weapons.  I'm guessing the larger, powered US mount, designed from the start for better sights was deemed worth upgrading while unpowered mountings were not.

 

There are other reasons for that too, after ww2 the soviets quickly went with the 14.5 for light AAA and a decade later this was superceded by the 23mm series. The latter saw incredible proliferation among the warsaw pact and client states, dominating all other light AA types.

[Paul Lakowski]

Hummm

 

We have an example of "Zampini's data" not being consistant with 'Facts" to dispell CW "Kind of makes the rest of his data somewhat suspect."

 

Then we have a single American AAA battalion downing a dozen Stukas with Quad HMG , to dispell the bulk of the reports that all consistantly state the HMG was being replaced by cannons due to the better effectiveness of the cannons.

 

So my question is, are we tring to make the facts fit the theory or the theory fit the facts?

 

A few exceptions in each case proves nothing...other than the fact that facts/opinions are often just 'averages' of results/experiences, and there are exceptions to every case.

[ABNredleg]

Actually, not. The naval water-cooled .50 had an adjustable rate of fire in the 500-700 rpm range (and the water-cooling meant that it could keep this up for much longer). The naval gun also came in twin as well as single mountings. The aircooled M2HB as used in the army's four-barrel AA mounting had a RoF of 450-500 rpm. Only the aircraft M2, with a shorter and lighter barrel and other changes, was faster-firing than the naval version, at 750-850 rpm.

 

The 20mm Flak 38 had a RoF of 420-480 rpm, i.e. the Vierling fired at about the same rate as the quad .50 - but the ammo was much more powerful and destructive.

 

Tony Williams: Military gun and ammunition website and discussion forum

209128[/snapback]

 

It is interesting to note that the USN, in its efforts to find lightweight weapons with high firewpower, put Army quad .50 mounts on three Essex class carriers in 1945. Six mounts was supposed to the equivalant of ten twin or fourteen single 20mm guns. The USN also developed the Mark 22 mount, which was an Army quad .50 mount with four 20mm aircraft type guns. Lots of firepower but not very reliable. It appears to me that stable mounts, good sights and high volume of bullets mattered more to the Navy than the power of the round.

Edited August 20, 2005 by ABNredleg

[FormerBlue]

Hummm

 

We have an example of "Zampini's data" not being consistant with 'Facts" to dispell CW "Kind of makes the rest of his data somewhat suspect."

 

Then we have a single American AAA battalion downing a dozen Stukas with Quad HMG , to dispell the bulk of the reports that all consistantly state the HMG was being replaced by cannons due to the better effectiveness of the cannons.

 

So my question is, are we tring to make the facts fit the theory or the theory fit the facts?

 

A few exceptions in each case proves nothing...other than the fact that facts/opinions are often just 'averages' of results/experiences, and there are exceptions to every case.

209846[/snapback]

I take it you were unable to comprehend the "40mm director couldn't solve firing solution for aircraft within 600 meters"? The 40mm might have been effective on the aircraft beyond that range but they were being hit by the 90mm.

 

"Single American AAA battalion downing a dozen Stukas..." It might be helpful to read the documents on the action. That was the single greatest use of AAA by US forces in Europe for point defense of a target that small. A quick read shows 11 AAA battalions in that operation containing .50s, 40mm, and 90mm guns. A closer read will raise that number considerably:

Three more AW Battalions joined the defenses on the 12th and by the 14th, the defense reached its peak: 16 gun batteries and 33 AW batteries, a total of 672 antiaircraft fire units.

 

I noted the Stukas as they were directly referenced and the unit scoring the kills was known. As more units arrived it gets harder to determine who hit what. Aircraft attacking the bridge consisted of Stukas, ME-109s, FW-190s, ME-210s, AR-234s, and ME-262s. Quite the performance mix.

 

There were over 200 casualities from .50 rounds returning to the ground. Volume of fire was heavy.

 

But hey, feel free to show me another example where .50s and light cannon were used that extensively in a land environment. Real world data, not tests. The review of that action pretty much stacked the kills to 90mm (on the 10th for example the 90s were credited with 28 of 47 downed) and then the .50s. Not just one flight of Stukas either.

 

Zampini's data is quite simply demonstrated to be wrong in that instance. Are you claiming the quad .50s didn't down the Stukas?

 

 

RIF.

[Yama]

I have no problem with that.  In 1941-1942 the Ki-43 was a good fighter.  The Japanese focus on dogfighting is reflected in the light armament.  The Ki-43 was able to handle the lightly armored enemy aircraft without a lot of problems.  So if you are speaking of the 1941-1942 period I'd agree. 

209764[/snapback]

 

But was it effective because or despite of its' armament? That was the whole point.

 

RAF won BoB with .303 armed fighters, yet went for the cannon as main armament ASAP.

[FormerBlue]

I used 1200 rpm and 46g (basic AP round) times 6 (for number of guns) and divided by 60 (to get a second's worth of firing), pretty straight-forward I would think.

209812[/snapback]

Fair enough. Just flashbacks to math class (no credit unless you show your work!).

 

If you are using 1200 rpm that is probably high given what Bojan provided for F-84 figures on what are similar guns. Maybe the F-86 was "dialed" higher but it's probably safer to go with the 1000 he provided. If you also figured all AP your higher yet as they carried tracer which is lighter than the AP.

[FormerBlue]

But was it effective because or despite of its' armament? That was the whole point.

 

RAF won BoB with .303 armed fighters, yet went for the cannon as main armament ASAP.

209870[/snapback]

Reference the Ki-43. Good question. Sakai mentions taking the radio out of his Zero to get the weight savings. The Japanese fighters were designed to save as much weight as possible. That was what gave them their dogfighting abilities. If we add bigger guns to the Ki-43 aren't we taking away some of their lightweight advantage? Without that, and the ignorance of their opponents in trying to dogfight them, they weren't really good fighters. So I'd say they were probably more effective with that armament early in the war. Later in the war allied aircraft didn't get suckered in so easily. The later aircraft also had self-sealing fuel tanks and armor. So they were probably a disadvantage at that point. Empty weight on that plane was only 1,975 kg. I don't know if adding two Type 99 cannon would have helped. I just don't think I've seen a lot of references to Oscars hitting planes early in the war and those planes not going down. The aircraft they faced early on weren't very "rugged."

[Guest bojan]

Fair enough.  Just flashbacks to math class (no credit unless you show your work!).

 

If you are using 1200 rpm that is probably high given what Bojan provided for F-84 figures on what are similar guns.  Maybe the F-86 was "dialed" higher but it's probably safer to go with the 1000 he provided.

209879[/snapback]

 

I should get F-86 manual soon so I will post a figure for AN-M3 on Sabre. AN-M3 on domestic trainers were also 950-1050rpm.

 

On the note of light AA - Yugoslavia replaced M2s on M51 Quad Maxton mount with AN-M3 in late '50s/early '60s... There was a video of that rig in use somewhere in Bosnia - that was one serious anti-infantry firepower.

For a discusion it may be interesting to note that there is Yugoslav document from late '50s on the light AA that notes that Flak-38V (20/4mm M38/51V) is somewhat better then M51 Maxton Quad, but that both are adequate for a short-range AA defence. Problem in comparisation is that Flak-38V is modernised one (/51 bit notes that) that had powered traverse and new sights.

Edited August 20, 2005 by bojan

[Bob B]

FWIW, The Japanese did put larger caliber guns on the KI-43.

 

The Ki-43 Ib used one 7.7 and one 12.7 MG.

 

The later KI-43 Ic through the end of the series Ki-43 IIIa al had two 12.7 MGs. Aircraft in these series represent over 5000 of the approx. 5900 built. Note that the Japanese 12.7s were similar to the Italian 12.7s and didn't have the same power as the US .50 cal Mg.

 

The also experimented with mounting two 20mm H0-5 cannons on the KI-43 IIIb. This was a light weight Browning style gun. There were only two of the IIIbs built in the spring of 1945.

 

Info. from Fancillon's Japanese Aircraft of the Pacific War

 

Interesting topic.

[FormerBlue]

FWIW, The Japanese did put larger caliber guns on the KI-43.

 

The Ki-43 Ib used one 7.7 and one 12.7 MG.

 

The later KI-43 Ic through the end of the series Ki-43 IIIa al had two 12.7 MGs.  Aircraft in these series represent over 5000 of the approx. 5900 built.  Note that the Japanese 12.7s were similar to the Italian 12.7s and didn't have the same power as the US .50 cal Mg.

 

The also experimented with mounting two 20mm H0-5 cannons on the KI-43 IIIb.  This was a light weight Browning style gun.  There were only two of the IIIbs built in the spring of 1945.

 

Info. from Fancillon's Japanese Aircraft of the Pacific War

 

Interesting topic.

209946[/snapback]

Well, since we're all over the place....

 

Are those numbers right? About 700 Type 1s with the majority being 12.7mm armed is what's normally quoted. This is kind of interesting:

http://www.j-aircraft.com/research/rdunn/n...ima_ki43arm.htm

 

I don't know. Japanese armament isn't my specialty. A/C #750 has apparently been recovered from Truk and is in Oz.

[Chris Werb]

On the note of light AA - Yugoslavia replaced M2s on M51 Quad Maxton mount with AN-M3 in late '50s/early '60s... There was a video of that rig in use somewhere in Bosnia - that was one serious anti-infantry firepower.

 

The Israelis did something similar putting two 20mms (that looked like wartime aircraft guns) in place of the 0.50s. I have seen this vehicle referred to as the TCM-20 though that designation may refer to the mount which was apparently also used on captured BTR-152s and RAMs. Some sources say the guns were removed from Dassault Ouragan trainer aircraft.

[JOE BRENNAN]

Hummm

 

We have an example of "Zampini's data" not being consistant with 'Facts" to dispell CW "Kind of makes the rest of his data somewhat suspect."

 

Then we have a single American AAA battalion downing a dozen Stukas with Quad HMG , to dispell the bulk of the reports that all consistantly state the HMG was being replaced by cannons due to the better effectiveness of the cannons.

 

So my question is, are we tring to make the facts fit the theory or the theory fit the facts?

 

A few exceptions in each case proves nothing...other than the fact that facts/opinions are often just 'averages' of results/experiences, and there are exceptions to every case.

209846[/snapback]

I don't see the comparison there, and am answering since I was the one who mainly questioned Zampini's data and accounts, I didn't OTOH say any one AAA Bn proved anything. Zampini just fudges stuff, pretty obviously if you look into it at all. If you look into it and find otherwise, especially on Korean War stuff, please let the forum know and we'll have another opinion on it. That's not relevant otherwise, just an aside because ACIG is sometimes badmouthed here, and Zampini's stuff left over there is a valid reason, perhaps taints other better stuff there, though I'm not sure. Anyway Z doesn't particularly push the idea F-86 armament was ineffective (may repeat such statements), not really relevant to that.

 

Back off that tangent (I started), to establish relative armament ineffectivness we'd have to show actual damage to MiG's statistically as in records was very skewed to damage rather than kills (and not just more than the case of F-86 damage/loss, much more, because of course the MG's will hit and wing more planes even if equally effective killers). That info is not available to us here in this discussion, now. I don't think the assertion that that was so in claims is really sufficient, and I'm not sure it's true; it's just been asserted so far.

 

Anecdotes of a Soviet pilot say that was true (I had seen that before this thread ), but the best blow by blow accounts from the Soviet records as opposed to general quite old recollections don't seem to back that up, don't mention a lot of damaged planes. Too, the Soviet statements are implicitly comparisons to the idea F-86's fell in droves to MiG cannon, and almost whenever they were hit, which they may have honestly believed happened, but US then-secret records simply don't bear it out. Among US pilots, some thought the .50 was a problem some didn't. A contemporary 20mm, M3, had reliablity problems in some known combats (with the Navy).

 

I think those dam/loss stats for MiG's are the core missing data, without which the rest tends to be projections of an assumption, "F-86's were far more effective, probalbly even reqd fewer rounds per kill than the MiG's but that was because of other factors" how do we know it was 100% or more due to the other factors without the key data?

 

So in summary among optional hypotheses about which the debate revolves "F-86 succeeded despite its armament": I question it. "It's clear F-86's should have been fitted with US 20mm available before the KW": I question it. "MiG armament was superior even for fighter combat": no IMO. "Eventually gun tech moved on to where a 20mm reasonable clearly superior to the M3 .50 emerged": I agree, ready for combat evaluation late in the KW, in GUNVAL.

 

PS re; Ki-43's the -I's used by JAAF in 1941-42 had a mix or 2*7.7, 1 each 7.7 and 12.7 and the definitive 2*12.7, I've never seen a source breaking down the numbers or timing of that evolution. Anyway I think that a/c's general success in that period is food for thought on the relative importance of armament weight. Also, to a greater degree than F-86 since such a smaller plane at earlier state of art, the design impact to include heavier armament, thus penalizing the plane in other respects, is more significant.

 

Joe

Edited August 21, 2005 by JOE BRENNAN

[istvan47]

boooohhhh, nobody care of me

 

 

I have spent almost one hour to write an enciclopedic post and nobody was interested!! It's a ungenerous world this one.

 

 

I'd want to repeat atleast some things here:

 

-if 4 M2 were enogh in the maxom mount, EVEN to the 20mm vierling, how hell in post wwII these 4 HMGs were often sobstituded by 2 20mm guns?

How is comparable the pratical range and the chemical payload ,cleary advantage of the 20mm??

 

-Let's say that the american 20mm guns were indeed not reliable and with few rounds in Korea: this is the same problem, incidentally, that happened in the BoB right? Also there was a problem with 20mms and the 8 303 brownings were deemed as more effective.

 

But this should say really anithing to us? I say not. It's not a guilty of the cal 20 if HIsso wasn't yet reliable and with ammo belts.

 

And ABOVE ALL it's not a guilth of every one in the rest of world if US weren't able to field reliable 20mm guns even in Korea. Or not?

After, when Sabre had even 30mm guns nobody cares if there wasn't anymore any M2-M3 on board. The sabre was the last HMG fighter in the world. It performed well, but this NOT mean that reliable 20mm guns weren't better, just like happened to the browning 303 v. Hisso when they latter were developed. Shame that Hurricanes weren't never fitted with 4 M2s as temporary solutions waiting Hissos, even if i heard that some huricanes were fited in URSS with 6 HMGs and another in the rear as defense arm.

 

However, that 7,7 weapons were sobstituted by 12,7 is a fact, but also the 12,7 were sobstituted in the evolution of the aircrafts, with the 20mm and then even 30mm.

 

Perhaps that even with 8 303 mm you can shot down also a B-17s, but this worth nothing.

 

Say that 12,7 didn't need to be sobstituted by 20mm is simply fihgtitng with every evolution happened with the A/A and aircraft evolution.

Bottom line, even the bombers after the B-50s and B-45s were fitted with 20mm guns as well

[CaptLuke]

-if 4 M2 were enogh in the maxom mount, EVEN to the 20mm vierling, how hell in post wwII these 4 HMGs were often sobstituded by 2 20mm guns?

How is comparable the pratical range and the chemical payload ,cleary advantage of the 20mm??

 

-

210130[/snapback]

 

IN WWII, the 20mm alternative to the M2 was the Oerlikon at about the same rate of fire (circa 450 RPM). Going from 4xM2 to 2xOerlikons would halve the rate of fire.

 

Post WWII, 20mm cannon development went at a pretty rapid clip compared to .50 development, so the Maxon upgrades were with cannon at around 650 to 1000 rpm (depending on the upgrade). This enables use of HE with much less, or even no, rate of fire loss for the mounting.

 

Also the ballistic advantage of 20mm rounds in WWII is not clear. We went around on this in a previous 12.7mm vs cannon argument on Tony's board and IIRC, the superior ballistic shape of the 12.7mm projectile resulted in the .50 having ballistics that were comparable to the 20mm weapons.

 

I'm guessing that this is not true with more modern 20mm ammunition and this is perhaps another reason that the 2x20mm approach made more sense post war than it did during the war.

[istvan47]

Thanks, finally someone take care of me!

 

 

IN WWII, the 20mm alternative to the M2 was the Oerlikon at about the same rate of fire (circa 450 RPM). Going from 4xM2 to 2xOerlikons would halve the rate of fire.

 

Post WWII, 20mm cannon development went at a pretty rapid clip compared to .50 development, so the Maxon upgrades were with cannon at around 650 to 1000 rpm (depending on the upgrade). This enables use of HE with much less, or even no, rate of fire loss for the mounting.

 

Also the ballistic advantage of 20mm rounds in WWII is not clear. We went around on this in a previous 12.7mm vs cannon argument on Tony's board and IIRC, the superior ballistic shape of the 12.7mm projectile resulted in the .50 having ballistics that were comparable to the 20mm weapons.

 

I'm guessing that this is not true with more modern 20mm ammunition and this is perhaps another reason that the 2x20mm approach made more sense post war than it did during the war.

 

 

 

partially agree. but you, excuse me, miss the point: even if you change 8 browning 303 with 4 Hisso or MG, you start with 7200 rpm down to 2400. Is it a losses ? No, because the 20mm shell weight around 10 times the rifle caliber.

So the 12,7: if a M2 projectile weights 48 gr, and an Oerlikon weights 120 gr., even if you cut the RoF from 2200 down to 800, where is the loss? You have simply around the same weigh focused on less projectiles.

 

Plus, you must add two factors: the useful load and the range.

As the range, M2 were found effective until 1500 max., not more and often less. With a 20 mm you have 50% more range, and see well, it's VERY important if you must face expecially aircarfts that starts from medium levels ( 1500-3000 mt) to dive on some targets. If you can reach 2 km you can make troubles to someone that looks for targets on the ground, while with a M 2 you are almost at the extreme range of use.

 

This is not the same as the ballistic that you mentioned, because this ballistic is similar between M2 and Hisso, only at low range, as example, between fighter combats. Not could be the same over 1000 mts, as Paul L. said, the speed loose of the M2 shell is much higher than 20 mm ones (arleady at 400 mts, 170 ms vs 120 or similar)

 

But wait, it's not all. If you have M2s you have just AP and Inc. shells. Now, the AP naturally, over 1 km hardly can shot something because it loose to much energy. The load of Inc. is less than 1 i say one gram. Even with HE the problem cannot be solved and i dunno if it was available (perhaps only for aircrafts).

As Tony said, the semi-AP of 20mm Hisso had 10 times the load of M2 and both incendiary and HE were available. And still a semi AP had around the same piercing power of a full AP M2.

 

With all these factors, i'd say that 2 AA or aircraft guns were quite better than 4 M2s. Not much, OK, but better. The M2 was and is a good weapon, reliable, cheap etc. etc. i personally not critic US if they had it as their main AA pattern, but 20mm was obviousely better, and i dont think that someone thinked differently, if we se how the evolution began to replace HMGs at any level with guns.

 

After WWII, of course, there was an improvement of 20mm weapons, as RoF.

But even so, pardon me, you missed this point: also the M2 can be improved, and this was in the form of M3 and many other things. If you want to improve Maxom mount you can teorically choose a faster RoF M2, let's say with 1000 RPMs. Now, you have still the same problem, and if you choose 2 .20mm guns you have still the problem of down the RoF more or less at the same example of WWII weapons.

 

But this is a surprise, because NOBODY cared about. Insthead to buy or modernize AA mounts with new version of M2s, everyone began to want at any level 20mm AA guns. This speaks volumes, as yuo can see how many RH 202, Oerlikon, Giat were made, and then the evolution sent to 25mm or even 30.

This cannot be explained with anything except the CLEARY superiority of the 20 mm caliber. If not, today we could been full of 12,7mm gatling or so.

 

Sadly, it appears that the unability of the US army to found a viable 20mm gun is still seen by someone as indirect proof of the "superiority" over the 20mm, thing maybe never thinked even by Browning engeneers.

Strange world this is.

[FormerBlue]

partially agree. but you, excuse me, miss the point: even if you change 8 browning 303 with 4 Hisso or MG, you start with 7200 rpm down to 2400. Is it a losses ? No, because the 20mm shell weight around 10 times the rifle caliber.

No you don't. You cannot add the output of the guns together for rate of fire. Do you not understand that? The rate of fire per gun dicates when the second round leaves the barrels. If I take 100 men with muskets, assume they can reload in 1 minute, that would be 100rpm right? Wrong. That would be 100 rounds in the first second and no rounds for the next 59 seconds. With the speed of aircraft that matters.

 

So the 12,7: if a M2 projectile weights 48 gr, and an Oerlikon weights 120 gr., even if you cut the RoF from 2200 down to 800, where is the loss? You have simply around the same weigh focused on less projectiles.

The 8" (203mm) 55Cal Mk 16 as installed in the USS Des Moines throws a 335lb (152kg) round. The rate of fire of the 8" was 7 rpm and it had 9 of them. So by your figuring that would be 63 rpm with 152kg rounds. Why not just go with that instead? We can take the figures for the USS Wisconsin's 16" (406mm) 9 cannon instead if you like. I believe there were rounds for that in the 2000lb category. Rate of fire would be (3 rounds per gun X 9) 27rpm tossing one ton rounds. Range is about 24 miles so all problems solved right?

 

Plus, you must add two factors: the useful load and the range.

Wow, those 16" cannon are going to rock in this category!

 

With all these factors, i'd say that 2 AA or aircraft guns were quite better than 4 M2s. Not much, OK, but better. The M2 was and is a good weapon, reliable, cheap etc. etc. i personally not critic US if they had it as their main AA pattern, but 20mm was obviousely better, and i dont think that someone thinked differently, if we se how the evolution began to replace HMGs at any level with guns.

9 16" would be even better. Followed by the 9 8" and then the 12 6". Dipping down to the Atlanta classe's 16 5" wouldn't be as good as there is no way to catch that throw weight of the Wisconsin.

 

But this is a surprise, because NOBODY cared about. Insthead to buy or modernize AA mounts with new version of M2s, everyone began to want at any level 20mm AA guns. This speaks volumes, as yuo can see how many RH 202, Oerlikon, Giat were made, and then the evolution sent to 25mm or even 30.

This cannot be explained with anything except the CLEARY superiority of the 20 mm caliber. If not, today we could been full of 12,7mm gatling or so.

Korea didn't see use of the Quad-fifty then? Everybody that I spoke with was wrong when they saw them?

 

You want to see a 12.7mm gatling?

http://www.gdatp.com/products/lethality/gau19/gau19a1.htm

But then I guess they don't exist.

 

Sadly, it appears that the unability of the US army to found a viable 20mm gun is still seen by someone as indirect proof of the "superiority" over the 20mm, thing maybe never thinked even by Browning engeneers.

Strange world this is.

The US couldn't field a viable 20mm gun? In which mount? For what? Naval use? What about this:

http://www.ussslater.org/weapons/20mm.html

 

Aircraft use? You are correct. None worked. They removed them from the P-38s as they couldn't get them to work at all. They installed 6" cannon from scrapped armored cruisers instead. They just couldn't resist the weight of the round.

 

Rate of fire matters. Speed of traverse matters. Sights matter. Reliability matters. Mobility matters.

[gewing]

Thanks, finally someone take care of me!

IN WWII, the 20mm alternative to the M2 was the Oerlikon at about the same rate of fire (circa 450 RPM). Going from 4xM2 to 2xOerlikons would halve the rate of fire.

 

Post WWII, 20mm cannon development went at a pretty rapid clip compared to .50 development, so the Maxon upgrades were with cannon at around 650 to 1000 rpm (depending on the upgrade). This enables use of HE with much less, or even no, rate of fire loss for the mounting.

 

Also the ballistic advantage of 20mm rounds in WWII is not clear. We went around on this in a previous 12.7mm vs cannon argument on Tony's board and IIRC, the superior ballistic shape of the 12.7mm projectile resulted in the .50 having ballistics that were comparable to the 20mm weapons.

 

I'm guessing that this is not true with more modern 20mm ammunition and this is perhaps another reason that the 2x20mm approach made more sense post war than it did during the war.

partially agree. but you, excuse me, miss the point: even if you change 8 browning 303 with 4 Hisso or MG, you start with 7200 rpm down to 2400. Is it a losses ? No, because the 20mm shell weight around 10 times the rifle caliber.

So the 12,7: if a M2 projectile weights 48 gr, and an Oerlikon weights 120 gr., even if you cut the RoF from 2200 down to 800, where is the loss? You have simply around the same weigh focused on less projectiles.

 

Plus, you must add two factors: the useful load and the range.

As the range, M2 were found effective until 1500 max., not more and often less. With a 20 mm you have 50% more range, and see well, it's VERY important if you must face expecially aircarfts that starts from medium levels ( 1500-3000 mt) to dive on some targets. If you can reach 2 km you can make troubles to someone that looks for targets on the ground, while with a M 2 you are almost at the extreme range of use.

 

This is not the same as the ballistic that you mentioned, because this ballistic is similar between M2 and Hisso, only at low range, as example, between fighter combats. Not could be the same over 1000 mts, as Paul L. said, the speed loose of the M2 shell is much higher than 20 mm ones (arleady at 400 mts, 170 ms vs 120 or similar)

 

But wait, it's not all. If you have M2s you have just AP and Inc. shells. Now, the AP naturally, over 1 km hardly can shot something because it loose to much energy. The load of Inc. is less than 1 i say one gram. Even with HE the problem cannot be solved and i dunno if it was available (perhaps only for aircrafts).

As Tony said, the semi-AP of 20mm Hisso had 10 times the load of M2 and both incendiary and HE were available. And still a semi AP had around the same piercing power of a full AP M2.

 

With all these factors, i'd say that 2 AA or aircraft guns were quite better than 4 M2s. Not much, OK, but better. The M2 was and is a good weapon, reliable, cheap etc. etc. i personally not critic US if they had it as their main AA pattern, but 20mm was obviousely better, and i dont think that someone thinked differently, if we se how the evolution began to replace HMGs at any level with guns.

 

After WWII, of course, there was an improvement of 20mm weapons, as RoF.

But even so, pardon me, you missed this point: also the M2 can be improved, and this was in the form of M3 and many other things. If you want to improve Maxom mount you can teorically choose a faster RoF M2, let's say with 1000 RPMs. Now, you have still the same problem, and if you choose 2 .20mm guns you have still the problem of down the RoF more or less at the same example of WWII weapons.

 

But this is a surprise, because NOBODY cared about. Insthead to buy or modernize AA mounts with new version of M2s, everyone began to want at any level 20mm AA guns. This speaks volumes, as yuo can see how many RH 202, Oerlikon, Giat were made, and then the evolution sent to 25mm or even 30.

This cannot be explained with anything except the CLEARY superiority of the 20 mm caliber. If not, today we could been full of 12,7mm gatling or so.

 

Sadly, it appears that the unability of the US army to found a viable 20mm gun is still seen by someone as indirect proof of the "superiority" over the 20mm, thing maybe never thinked even by Browning engeneers.

Strange world this is.

210268[/snapback]

 

 

AFAIK You are forgetting two basic facts.

 

The US was, in WWII, usually shooting at FIGHTERS. These were not as hard to kill as bombers.

 

 

The higer rate of fire, while it doesn't put any more weight of shells on target, makes it MUCH easier to hit a fleeting target.

 

So if your 2x20mm guns have 1/3 the chance to hit...

 

Though this may be an oversimplification, I believe it IS a valid point.

 

IMO, Though the US should have introduced something like the M-3 years earlier, and gone to 4-6 of them with more ammo instead of 6-8 m-2.

[tomcat_1974]

About Mig 15 weapons.. I hardly consider it a failure. Guys remeber East Front aierial fighting during WW2. The majority of Russian highest scoring Aces flew P-39 AirCobra. They never complain about the weapons. The learn how to use them. For the ones that don't know P-39 had a 37mm cannon and 2 M-2 machineguns. Depensing on subversion it could had 4x .30 cal machineguns or another 2 x M2's.

Also russians used Yak-9 K and Yak 9 T.(37mm and 465 mm cannon armed).

 

They had exeperience with this kind of weapons. They used them on Luftwaffe tactical airforce.

[Tony Williams]

Damn - take a day off and it takes ages to catch up!

 

On the fighter armament issue, there is one point made above which I feel needs emphasising. I said originally that an armament of good 20mm guns was better than a similar total weight of armament in .50 guns. The fact that the USA wasn't able to get the 20mm Hispano working properly during WW2 is well recorded (see: http://www.quarry.nildram.co.uk/US404.htm ). There is no doubt that the US made an effort to solve the problems, first (without, it seems, much success) in late WW2, resulting in the M3, and then in the late 1940s with the development of the M24 and further work to the M3. There appears to be conflicting evidence about how successful these later improvements were, but it is important to bear in mind that aircraft guns were 'highly tuned' (to use automative terminology) and even the best were never 100% reliable, so individual anecdotes about guns jamming don't mean much. In particular, it was not uncommon for the stress of high-G manoeuvring to cause the belt feeds to jam - something which still afflicted the F-8U Crusader in Vietnam.

 

On balance, the best solution for the F-86 would probably have been to develop the .5" and 20mm versions in parallel: the .5" version would have been out first, but the 20mm could have followed on later when the installation had been debugged, in good time to perform useful service in Korea.

 

Incidentally, in WW2, the Japanese and Italian 12.7mm guns were ballistically less powerful than the US and Russian .50s, but did benefit from HE shells which (sometimes) helped to restore the balance a bit.

 

To turn to AAA use: the .5" BMG was ballistically superior to the WW2 20mm Oerlikon because the proectiles were a much more aerodynamic shape. It therefore had a longer absolute range. However, the .5" relied almost entirely on kinetic energy to do the damage and that fell off steadily with range, whereas the 20mm inflicted much of its damage through the chemical energy of the explosives, which did not fall off at all with range. So the effective range of the 20mm was probably greater, particularly since it needed a small fraction of the number of hits to inflict equivalent damage. However, in all cases with manually-aimed AAA (whatever sights were used) the effective range was limited more by the skill of the gunner than anything else.

 

I do not doubt that the quad .5", with its power-operated mount, was well able to shoot down aircraft at close range. However, I think that twin 20mm in the same mounting would have been even more effective, and the USN certainly seemed to agree when you look at the speed with which they replaced their .5 mountings with the 20mm Oerlikon during WW2.

 

Tony Williams: Military gun and ammunition website and discussion forum

[Guest bojan]

FormerBlue, I got it finaly - ROF for AN-M3 mounted on CL-13 Sabre is 1150-1250 RPM... F-86E is same. However F-86D is 950-1050... Why it differed even on the various marks of the same aircraft I have no idea - maybe some problems with radar and vibration or gun-gas ingection in engine - but that is just my guess...

 

PS. Most serious firepower - F-47D (F) Thunderbolt in servise with Yugoslav AF - those were from France (hence (F) in designation) and were delivered w/o armament. They were armed with 8 x AN-M3 with ROF 1150-1250rpm...

[FormerBlue]

FormerBlue, I got it finaly - ROF for AN-M3 mounted on CL-13 Sabre is 1150-1250 RPM... F-86E is same. However F-86D is 950-1050... Why it differed even on the various marks of the same aircraft I have no idea - maybe some problems with radar and vibration or gun-gas ingection in engine - but that is just my guess...

 

PS. Most serious firepower - F-47D (F) Thunderbolt in servise with Yugoslav AF - those were from France (hence (F) in designation) and were delivered w/o armament. They were armed with 8 x AN-M3 with ROF 1150-1250rpm...

210446[/snapback]

Thank you. That is kind of different. F-84 and F-86 using different rates of fire. I'm surprised that they rated them different. It would be nice to find the T.O. for the F-80 to see what that was rated at. Probably yet another rate.

[Miner]

FormerBlue, I got it finaly - ROF for AN-M3 mounted on CL-13 Sabre is 1150-1250 RPM... F-86E is same. However F-86D is 950-1050... Why it differed even on the various marks of the same aircraft I have no idea - maybe some problems with radar and vibration or gun-gas ingection in engine - but that is just my guess...

 

Probably something to do with the radar/computer(valve analog). The mix of complex valve electronics and guns was not a happy story leading to some weird rocketry pre guided missiles.

 

Can anyone confirm the story that the Genie (unguided rocket with nuclear warhead) was dropped like a bomb until it came to the end of a rope when the rocket was ignited, just hoping the bang was big enough.

[larrikin]

It seems to me that the .50vs20mm debate is of a similar nature to the BARvsBren debate. As the US couldn't get it right with the system that everyone else went to it follows that the US was correct in the first place.

[FormerBlue]

It seems to me that the .50vs20mm debate is of a similar nature to the BARvsBren debate.  As the US couldn't get it right with the system that everyone else went to it follows that the US was correct in the first place.

210554[/snapback]

The tactics of the organizations using BARs and Brens was different. There is also the issue that the BAR was supporting semi-automatic armed troops whereas the Bren was supporting bolt armed troops. But you see the .50vs20mm as similar in nature? What exactly is similar?

 

It's amusing to me that those that view the BAR from a Brenish perspective are in countries that have adopted the SAW in one form or another.

[CaptLuke]

[but this is a surprise, because NOBODY cared about. Insthead to buy or modernize AA mounts with new version of M2s, everyone began to want at any level 20mm AA guns. This speaks volumes, as yuo can see how many RH 202, Oerlikon, Giat were made, and then the evolution sent to 25mm or even 30.

This cannot be explained with anything except the CLEARY superiority of the 20 mm caliber. If not, today we could been full of 12,7mm gatling or so.

 

 

210268[/snapback]

 

With 20/20 hindsight, the US in WWII probably could and should have put more emphasis on fast firing, reliable 20mm weapons, though I think I've outlined why I think the 20mm advantage over the .50 may be less than it might appear.

 

Post WWII, however, you can make an argument that 20mm weapons offered too much extra cost for too little improvement over .50/14.5mm weapons. IMHO this is especially true of the less powerful 20mm rounds, like the US and German rounds that were just necked out cases from .60 and 15mm heavy machine gun projects.

 

23mm/25mm/27mm/30mm seem to be the calibers that, for a small incremental size and weight penalty, offer considerably more power than the 20mm weapons. Perhaps the Germans got it right at the end of WWII: 30mm high velocity for AA and a 30mm revolver cannon for planes, and it was only the investment and habit of using 20mm cannon that kept them in play so long.

 

Going to the higher calibers also fits in with one of Tony's points earlier: if you're going to spend the money on a powerful mounting, which is very important, you might as well put some bigger guns on it.

 

The optimal high/low mix for US AAA might have been .50 in free mounts and cheap, unpowered, multiple mounts for low end air defense complimented by expensive powered mountings for multiple weapons in the 30mm class, which IIRC, they had a good round for in the Naval 1.1", though they needed much better guns.