IIRC correctly the USN used a water cooled .50 with a low rate of fire (450?). If you compare this to an air cooled 20mm with about the same rate of fire, the 20mm should be much more effective: it has a more destructive shell and the .50 does not have weight or rate of fire advantages, which is what .50 partisans tend to site as its advantages.

If the comparison was, for instance, between a mount with twin air cooled .50s at 650-700 RPM, and a single 20 mm Oerlikon at 450 RPM, the effectiveness calculation might be different, though we would just be having the aircraft armament argument all over again to talk about how the calculation would change.

The quad .50 is a whole different animal from the USN single mount: four barrels and a powered mounting. Given approximately equal ballistics and belt feed (which I would expect to translate into a practical rate of fire advantage over the Oerlikon and German 20mm Flak) I would guess the quad .50 to be near the German 20mm quad in effectiveness.

So I think the numbers are skewed because the USN had pretty much the worst case scenario for .50 AA effectiveness and, if they had pushed for lighter, higher rate of fire .50 AA, possibly like the twin mounts on PT boats, they might have liked the .50 a lot more.

The bridge on the Rhine scenario, OTOH, is best case for .50 AA: all quad mounts with time to deploy around a single high value target. This is why I don't see a contradiction between your notes on the .50 as an AA weapon and the performance at the bridge.

In any case, once the Kamikazes are an issue, both the .50 and the 20mm are out the window.

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

Apart the very funny posts of formerblue ,
this topic (resurrected by miself, great ) send us other reasons to be read.

IMO, we can draw some conclusions:

-M2 vs 20mm. We can argue if M2 areonautics were better or not of the old oerlikon MgFF, as example.But apart this, the evolution has shown that "bigger is better".

Surely that M2 was a ugly beast to manage. If a fighter has 6 of them, you are in trouble. Some pilots of P-47s stated that their armament was more effective than previous fighter flown with 20mms. But it really worths?

Also in the BoB Brownings lights were effective, after all, to shot down a thousand of german A/C. But , despite their RoF was atleast comparable with a minigun, they were away from the ideal. The HE bullets for them was considered "ridicolous", and the minimum caliber to fire HE was considered as the 20mm. If nothing else, the MG FF was capable to shot a very powerful shell.

British were in trouble to making reliable Hisso armed fighters. But the unreliability of these and the short time of fire were serious issues.

So we can say that perhaps the most successfull AA british weapon was the Browning 303, but even if it works quite well, there was a different needing to be satisfied. This was well shown when (to answer to Formerblue about the issue of "how" damages are evalued) by several german bombers returned to home with over 220 holes of MG. Naturally, many were shot down, but the problem was that in a typical tail engagement, even 200 hith could have been not enough, and this mean atleast two fighter that had fired all their ammo on this bomber. Waht if they had heavier weapons? It could had been better. Also in Spain there were complaints about the SKAS letality (not abot reliability, not about RoF, but just leta lity)

But how heavier? US tough it was enough the M2. reliable, powerful, cheap. Why not? US didn't faced heavy bombers, after all. The vanilla 20mm with their weight, low ROF , high price and last 60 shell drum, wasn't exactly ideal.

But the history became furhter, the reliability was improved, the bels inshtead of drums and powerful fighter engines. So the things happened. Hurricane MK II had before 8, after 10-12 MGs, just like Typoon. After, they switched to 4 Hisso. There was a reasond behind that? One could had been the ground attack, but also in AA mode they were indeed more effective.

How a M2 fighter could had done as anti-bomber weapon? I feel not very well.

But of course, there must be differences.
Italians and Japs fought with much weaker HMGs allied bombers. despite italians HE shells, not so effective like italian historicians claims, the vickers style machines were much weaker than M2 browning, with 40% less energy. Even so, with only two MGs, there were cases in wich axis fighter shot down with a few shots heavy bombers. Trick? frontal engagements.
Now, i don't think that 6 M2s were less effective in this side, if you shot at the front or the sides of enemy heavy bombers you will do something. Even if you pursue on the tail with 6 M2 you will have something good.

Maxom mount was good above all for the fast turn rate. It could do as well good things.
Even so, 12,7mm was sobstituted by 20mm. Even the maxon was post WWII "improved " with 2 20mm guns insthead of the 4 12,7mm. This is a clear proof of what kind of superiority was in the 20mm insthead of the 12,7mm.

Perhaps that at the beginnings of the WWII M2 HMG was the better choice. At the mid war, perhaps equal. At the end, definitively less effective. This because the improveing of the 20mm weapons at all the levels. And despite the fact that germans bombers were gone.


So i think that 6 HMGs were good. Perhaps also 12 LMGs. But the better overall arrangement was the 20mm. for special anti-tank, anti-bomber things, stuff of 30-37mm were better as well. Japan tried to put in their fighters any sort of heavy gun. Even 75mm was tested to shot down B-29s. And this, regardless of the good results of M2s in many combats, but also regardless of the american pride (those shitty 20mm european guns! ).

As Korea war, i am happy that someone seems thinks the same of myself: Tony has said, better 4 23mm insthead than the Mig standard armament.

As this issue, perhaps the Mig overall weaponry was quite superior ( AA combats, bomber interceptions, ground attack), but as fighter-to fighter weapon, the problems was that the russian guns not only had lower RoF, but also had slower shells, even if on the longer ranges these shells looses less energy than a 12,7 (but over 500m who care??), and a limited ammo. What hell you can do something if you have just 6-8 sec. of fire? And if your RoF is barely over 2000 RPM? And if your guns are lacking a rangefinder?

The Sabres can close the range and fire with M3s with precision. As the accounts of the air battles, i have read that Mig fire often as firsts , but usually missed the sabres, while the sabre then in the furball descended at levels on wich they had better capabilities overall than the Migs, and then fired on them many strafes, hitting time and time until their target started to smoke.

I am only wondering, what if some field modifications lead Mig 15 with the 37mm removed and:
-4 NS 23 with 80 R each or
-3 NS 23 with let's say 120 each or
-4 B-20 or skhak guns with 150-160 R. each.
-even 2x20mm (insthead of the 37mm) plus 2x 23mm or
-6 UBT 12,7mm (sabrerovsky!)
-4 KPV(?)

All this weapon systems should had been MUCH better than the original.
Personally, 4x20 or 2x20 plus 2x23mm sems to me the better choice. Plus i'd add a battery of AA rockets against B-29s (rockets proved better than heavy guns in AA and AS roles, atleast for the reasons they don't compromise the design of hte aircraft). After all, RS family was the first real AA roket of the world. I bet that against B-29s, if not a copy of the R4M, even RS-82 could had done good things.

Naturally it'ds arguable how this question of weapon was important. For me, a weapon lighter but that is precise on hitting the target is better than a heavier that usually missed. Migs usually fired on the sabres, and usually missed them even when they had the start of the battle, while the Sabre's fire was atleast precise to hit the target. Usally, it was wondering how the Migs were able to withstand to the HMG fires, not less than the germans bombers of BoB. But at the end, usually, one or two of hte reds were missing at the landing.

Rougly it's all i can say about.

You misunderstood. If you are calculating the weight of projectiles on target you do need to account for firing rate. The M3 fires faster than the M2 so the weight of shells on target is obviously higher.

You misunderstood. The B-17s flew high enough that small rounds were not a factor. That was my point.

And you keep pointing to naval combat. AAA fire from ships is different from land as there isn't a lot of hill and tree cover in the Pacific. But hey:

USS Des Moines. Nothing less than 3" is useful in that environment. 5" of course being optimal.

Interesting that this quote kind of confirms the cover point. But I found what I had mentioned earlier. The British Kerrison Predictor that was used with the Bofors was tested in the US when the 40mm was adopted to replace the 37mm. The director was found to not be able to "solve" the attack problems on aircraft within 600 meters. The quad .50 was used to cover that dead zone.

Why the predictor didn't work within 600 meters isn't listed. Again, for maybe the 10th time, speed of traverse would be my guess.


Quality of the gun on a multimillion dollar aircraft doesn't matter? Why not save the cash and replace it with an M2 then?


They did well because of their armament. The standardization of caliber made for an easier gunsight solution. 6 fast firing guns meant that a 10th of a second burst still put a number of rounds on target. That is critical when the target is moving so quickly.

We can distill it down quite easily. If you truly believe that the .50s were ineffective find a proportionate number of references to Migs returning after having been hit. The .50s put rounds on target quickly. Increased the chances of hitting. Your contention boils down to the rounds didn't do enough damage. Prove it. Migs.

Somewhat related, this is rather interesting also:
http://72.14.207.104/search?q=cache:lnTb-U...15+damage&hl=en

Thanks for the clarification on the naval .50; serves me right for going from memory.

When we're talking specific mounts, I think the quad .50s power operation, improved sights, and belt feed give it some balancing advantages against the manually operated, clip fed Vierling.

This led me into a slightly different line of thinking: I'm starting to wonder how much we may be dancing around better mountings being more important than better weapons?

- Tony, your own figures show a predictor improving 40mm AA performance by 2X and a gyro sight improving 20mm performance by 6X. It is hard for me to believe that these kinds of factors wouldn't be more significant than the rate of fire differences and ballistic differences we tend to talk about between most different 12.7-20mm weapons and most different 37-40 weapons.

- The single .50 AA has no fans, but the quad mounting, which featured power operation and reflector sights, has some anecdotal support and the ultimate complement: it's still around in vastly updated form.
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.

I wonder if a good chunk of what we're seeing in the .50 to 40mm range is that larger and later war weapons tended to have much more effective sights and mountings?

For 12.7mm and 20mm weapons it would be interesting to know how single, manual mountings compared to multiple powered mountings and, in turn, how these multiple powered mountings might compare to single 37-40mm mountings. I'm guessing that all types of mounts for 12.7mm and 20mm are lumped together in the effectiveness data we're talking about.

edit

back off topic (sorry, I'm tired and got blather-typing. feel free to ignore. )

I was originally bothered that the 25mm gun from the AV8B was not the gun for the f-35, but then I saw that the 27mm Mauser had some advantages.

Then they decided to use the 25mm gun. and afaik, they are STILL only talking about 150 rounds on board.


After readig "Rapid Fire" a couple times, and reading most anything I can find on the web, I find myself wondering why we DO stick with the m61. It seems to be reliable, and we know it. Those seem to be the only real advantages, unless the afaik larger dispersion is considered an advantage. Tony DID manage to convince me that their relatively large bulk is not a great idea. The weight isn't all that hot compared to other guns either.

I would think that the 30mm 4(?) barrel gun for gunpods, or the 25mm whether in the Equalizer or the GE(?) Gast style gun would make somewhat more sense. GIven that most other countries seem to have decided that 20mm (particularly 20x102mm) isn't really damaging enough on target, that is. Perhaps a longer barrel version would help, but that is more weight etc.

I'm not sure the Mauser 27mm, or the french 30mm (the newer one) or the russian 23 or 30mm guns might be more generally usefull. at least more compact and lighter for the relative performance.

You misunderstood. I was referring to the choice among modern aircraft cannon. There are better guns available than the 20mm M61, but given the way fighter guns are used these days the question of whether it has a 20mm, 25mm or 30mm aircraft cannon isn't a major issue.


I have never said that the .50 was ineffective: only that a good 20mm would have been more effective.

Tony Williams: Military gun and ammunition website and discussion forum

I don't think that the belt feed is that significant an advantage because the effective RoF of an air-cooled gun is limited by barrel heating rather than ammunition supply (the maximum continuous rate of fire of an M2HB to avoid overheating is only 40 rpm - yes, that's forty!). And when you think about how AA guns were used, it tended to be in brief bursts of fire since aircraft weren't in range for long, so there would usually have been time for reloading. The main advantage of belt feed is that it saves on the extra bodies needed to keep dashing around changing the magazines.

However, I agree with you over the importance of the mounting. A powered mounting has clear advantages over a manual one, and sights are also important (although it should be noted that the Flakvisier on the German 20mm mountings was a sophisticated modern sight - one which IIRC they simplified later in the war!). This is what I said in 'Rapid Fire' concerning current light naval cannon:

"The combination of mounting and sighting system does far more to determine the usefulness of a light cannon than the does the calibre. An unpowered mounting and open sights limit the weapon to engaging nearby stationary or slow-moving targets in reasonably calm seas (especially when fitted to small craft). In contrast, a stabilised mounting and a computer sight will convert almost any cannon into a highly effective surface-fire weapon with a credible back-up anti-aircraft performance. Broadly speaking, unpowered free-swinging mountings tend to be of 20mm calibre, with 25mm seeing some powered assistance and 30+mm fully powered and often stabilised."

The final point I think answers part of your question: the more powerful an AA gun is, the more worthwhile it is to fit it with a complex and expensive sighting and mounting system. The ballistic and destructive performance of the .50 is really not good enough to be worth spending a lot of money on advanced sights and mountings: which is probably why many of the quad mountings were converted to twin 20mm cannon, as described above.

Of course, the quad .50 earned its formidable reputation in another role altogether - cutting swathes through Korean massed infantry attacks!

Tony Williams: Military gun and ammunition website and discussion forum

You made the assertion that the F-86 was successful in spite of it's armament. I guess we could also say it was successful in spite of it's not having the J57 engine and much improved aerodynamics. But hey, that would be the F-100 Super Sabre - not available for that war.

The M39 wasn't fielded until 1953. Which is also the year the F-100 arrived carrying them. It was also the year that the first Sidewinder was fired. Too late for that war. Yes, I am aware some F-86Fs did see combat (test) M39s. But that's 1953 again. Still leaves a lot of combat in 1950, 1951, 1952. F-86Fs also had a more powerful engine, better guns sight, and better slats than the A model.

Unreliable M3 20mm cannon would not have improved the F-86. Its armament was fine. Unless you can find all of those Mig-15s that were able to shrug off the .50s?

Back on track of AAA in WW2.

There are a number of situations that need to be dealt with. Not every country had the same situations. We've already touched on heavy bombers (which require something really big to reach).

The weapons also need to be segregated into static defense and mobile defense. The towed 40mm had to be set up before use. It's not particularly mobile. The quad-fifty was very mobile (half track version specifically). The Germans also had the half track for their 20mm and the modified tank chassis (Mobelwagen IIRC) for the 20mm and 37mm. The US M42 Duster provided 40mm mobility but that wasn't WW2. Zsu-23 also comes to mind.

The Allied forces on the Western Front didn't have to deal with a lot of ground attack. Well, outside of Allied aircraft anyway. Other than Remagen I'd say it was pretty much wasted effort for the US.

Tank Destroyers was a failed concept. Tanks need to fight tanks. Likewise, aircraft need to fight aircraft. At least in WW2. German ground attack a/c weren't a significant threat in the west because of the fighters - not AAA.

Well, by same token we could then argue that .303 was excellent fighter gun in WW2, after all fighters armed with them did shoot down a huge number of aircraft. Ki-43 had juts two of them and they totally wiped out the opposition in 1941-42. I guess you could argue it is 'because of the armament' and could be disproven only by a 'proportionate number of references to Allied fighters returning after being hit'.

The US also used a lot of 37mm AA, both towed and in HTSPs - the latter in combination with two 0.50s. The latter can't have been that bad as they were still in the front line in Korea - though in a surface-to-surface role. The M42 was preceded by a similar twin 40mm SPAAG based on the M24 - the M19. M19s also served in Korea but AFAIK were too late for WW-2.

I think the absurdly high figures given for amounts of 0.50 rounds needed to inflict a kill by the US Army are probably because not only 0.50s in AA units were counted.

Some extracts from 'Flying Guns – the Modern Era: Development of Aircraft Guns, Ammunition and Installations since 1945' (Emmanuel wrote this chapter!):

"Almost all F 86s that saw service in Korea were armed with six .50 inch M3 machine guns. The M3 had a high muzzle velocity and a high rate of fire (1,200 rpm) but nevertheless the firepower of the Sabre was unsatisfactory in combat against the MiG 15. The Soviet fighter was well armoured and had the sturdy construction that could be expected in a fast jet fighter aircraft. One of the most successful Soviet pilots of the war, Yevgeni Pepelyaev, commented:

The US Browning .50-calibre guns bounced off our aircraft like peas! It was routine for our aircraft to return home having taken 40 or 50 hits.

In US figures this deficiency in firepower translated itself in a relatively high number of enemy aircraft claimed as “damaged” or “probable” versus the number of enemy aircraft claimed as “destroyed.” And it is likely that many of the aircraft that American pilots thought to have shot down, actually limped home. The first recorded Sabre kill, by Lt.Col. Bruce Hinton on 17 December 1950, was a revealing event:

I picked the up the closest enemy, which was MiG No.2, put my pipper on his left fuselage about where the main fuel tank should be and closed. I was using stadiametric ranging on the gun sight with a 30-ft span set. …
When it looked like 1,500-ft range, I let go a short burst and saw strikes against the middle left fuselage and from the right wing where the bullet pattern from the six .50-calibres had sprayed across. The holes appeared to cause some kind of leaks from either internal fuel or smoke from the API ammunition I had fired. …
Range was about 800 ft and I pressed the trigger for a good burst into his engine. Pieces flew out, smoke filled his tail pipe, then flame lengthened out of the opening. He immediately lost airspeed…
In an attempt to finish him off, I made a diving turn, putting the pipper on his forward fuselage. At this point, I fired a very long burst. The API flashed and twinkled on the left and right wing roots and the cockpit area. He rolled on his back and dived, trailing smoke and flaming towards the snow-covered ground. …
The performance of the MiG 15 had been far better than we were told. The airplane also appeared to be a lot tougher than I had imagined when it came to shooting it down.

Hinton had consumed almost all his ammunition. On average 1,024 rounds had to be fired to destroy a MiG 15, out of a normal ammunition load of 1,602. More to the point, even with six 1,200 rpm guns it takes eight and a half seconds to fire 1,024 rounds – an eternity in air combat. Col. Glenn Eagleston complained that of all MiG-15s hit by the fire of the Sabres, two-thirds still managed to get away."

The 20mm M3 and the electrically-primed M24 were the subject of an intensive development effort in the late 1940s in order to resolve the reliability issues. The improved M24A1 was available in time for the Korean War and four M24 cannon were later the standard fit of the F-86K.

It is reasonable to conclude that if in the late 1940s the USAF had had foreknowledge of the results of air combat in Korea, they would have specified the 20mm M3 or M24 for the F-86 from the start. As it was, the Project Gun-Val planes (which tested the M24 as well as the M39) were very much experimental and the cannon installations needed a lot of development before they were satisfactory.

Tony Williams: Military gun and ammunition website and discussion forum

But the US didn't have absolute air superiority from the start, or everywhere all the time during the entire war. And it would be little consolation to soldiers on the ground that the fact they couldn't fight back saved some money

As for TD's being a failed concept, that is simply to sweeping a statement to be true.
And ultimatly it was the heavy bombers that caused the a/c to stop being a threat, so what you really need is bombers to shut down the enemie's a/c and tanks: everything else is a diversionary effort

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. You can go back further and look at the Fokkers in WW1. Lightly armed also but very effective for the time.

Unless you have evidence that the assortment of allied aircraft ranged against the Ki-43 were able to handle it in 1941-1942?

McConnell:
Mig cannon didn't make his aircraft blow up in the "earth shattering kaoboom" we were lead to expect.

Davis:

Two Migs in 2 minutes. No reloading allowed. I guess it didn't take the full load to down them each?

Seem to be working fine.


It's reasonable to conclude they'd have sped up development of the later fighters and cannon. Maybe the F-100 could have entered combat.

Interestingly he didn't get his first Mig. Call it "Buck fever." He opened up out of range and didn't get enough hits on target (although he did hit).

I still don't see those large number of Migs. Large number of "probables and damaged"
is the nature of the fight. You don't always get to watch the enemy blow up. If he leaves smoking you don't get credit for a kill. I suppose it would be better to claim them all and inflate the "kill" category?

Again I think some of these statements (type I was thinking of in earlier responses) are actually non-quantative, hard to back quantitatively and therefore the specific conclusion can be questioned.

1. But how often? Again a higher damaged to killed ratio is inherent with a lighter gun, even assuming it is equally effective; depends on how much. As I said in accounts like Naboka's (plodding transcription of the Soviet records enagement by engagement, including for part of Pepelyaev's tour) there are relatively few mentions of cases like that, not a huge number of damaged planes mentioned at all. It doesn't mean there weren't others not mentioned, but I don't know. Plus the implicit frame of reference of Pepelyaev's statement is again the view that says they downed lots and lots of F-86's and most of those they fired at, but this cannot be supported in the US records. Actually plenty of F-86's were hit and survived also, more than 1/2 perhaps 2/3, and as little as 10% of what they claimed actually downed. And in general quotes of pilots of the 324 amd 303 divs (almost all those you see in English in books, even TV shows) are somtetimes at odds with known facts in *their records*, let alone US ones. Part of this problem was probably telling them to forget they fought in Korea for 40yrs, then asking them to tell all about it.

2. Was it especially high (original source for that?). Even if so, the ratio among dest/dam/prob *claims* is also a function of how rigorously they are culled down before crediting, not just the actual effect on the enemy. If you add up US dest/prob/dam they would exceed actual Soviet losses by something like, or more, than the Soviets claims of destroyed alone exceeded the US losses, order of 10 times, because they apparently credited most planes their pilots got a reasonable shot at, and gc photo of, much different than actually downing a plane. As to "destroyed's" limping away we know that the overall ratio of US destroyed credits to real MiG losses (70%+) was pretty good by WWII standards, so no evidence that was particularly prevalent, relatively. Again we'd need actual MiG damage v. loss stats to say anything definitive on this issue comparatively.

3. The M3 20mm had at least some reliability issues with the Navy in Korea, as in Nov 1950 when F9F's killed 2 MiG's (claimed 3) including the first confirmable in Soviet records, they would probably have had more without gun failures.

4. So I question this specific conclusion. As of F-86 design and even after, USAF had stats studies saying *existing* larger cals were not superior. GUNVAL, per the chapter on it in Thompson/McLaren "MiG Alley, Sabres vs. MiG's Over Korea" only tested the T-160 (M39) in combat, a later weapon. Kill rates were "above average", not clear slam dunk apparently.

Joe

That is the M39. Damage rate is much higher than kill rate. Numbers aren't out of line with .50 experience.

On McConnell, yes obviously he wasn't blown up. Davis [edit: I mean Jabara, for some reason I thought of him when you said Davis] specifically believed in the .50; apparently he had no interest in trying out the GUNVAL planes on his second tour.

But, source note, I would not take literally accounts like those on acepilots by Diego Zampini, they're let's say "based on a true story" . There's no way to say Fedorets downed McConnell, the Chinese pilot Jiang Dao-ping also now specifically claims it*. The Soviets claimed 5 F-86's that day, the Chinese at least Jiang's claim and probably others, and 2 NK divs were flying by then. 3 F-86's were lost, tied for the highest in one day by MiG's in the war. Accounts of the various sides, esp Soviet v. US, usually agree well on time place and rough circumstances; disagree on results almost always, and usually the blow by blow of who turned which way and saw and attacked what is very hard to match too. It's usually impossible to factually say who downed whom. Diego didn't have better sources, he dramatized based on fewer sources (all those inconsistencies and other claims didn't get in the way ).

* same with the another famous ace downing, George Davis KIA CMOH in early 1952, competing Soviet and Chinese claims each have inconsistencies with the US account but then, Davis was downed.

Joe

Zampini's data is completely inconsistent on one date*. He claims no Russian or Chinese Migs were even engaged in combat on a day that McConnell? claimed a kill. I can see conflicting claims on what went down and who shot at whom but are we really supposed to believe the McConnell wouldn't even know if he was shooting at an airplane? That one is a little rich.

I could look it up but I'm pretty sure it was McConnell. Boots would be the other possibility as I was looking at his data too.

You kind of lost me on that whole post. I'll just repeat what I said more directly: Diego constructs stories of pilot on pilot combats that can't really be supported from records as certainly what happened, but he presents it as if it is. If McConnell says he fired at somebody, we'd take that at face value; if Fedorets said he fired at somebody likewise. If they said they downed somebody unfortunately that's seldom specifically provable in large combats. If somebody says specifically Fedorets shot at McConnell or vice versa, that's made up, in a large combat, you can't tell that.

Besides that Diego often credits Soviet pilots with US non-MiG or non-combat losses in these "detailed" accounts; occasionally with non-existent losses (see his article on that site about Fedorets, credits him with Vincent Stacy who was never shot down).

As to verifying US pilot's scores, the source Diego uses for the Soviet losses isn't complete (but fairly close), and clearly wasn't written with detailed info on Chinese/NK losses. On Chinese losses I've found fewer than 30% of their admitted total specified date by date, and NK losses aren't known in detail at all except a few via the defector No Gum-suk. Therefore no Soviet loss on date of claim means nothing after around Sep 1951 (previously, virtually all MiG opposition was Soviet). That said related back to dest/prob/dam ratio's, some MiG losses represent the latter two categories, whereas we quote individual scores as "dest" only. So while dest credits~70% of the real MiG losses, we'd expect individual scores to check out at less than 70%, and that's the case AFAIK for pre Sep 1951. For 1953 you can't do that accurately, yet.

Joe

My point was, for one particular day, his claims state no Migs were in the air. Yet a US pilot, not an inexperienced one at that, was shooting at a Mig.

Kind of makes the rest of his data somewhat suspect. If Zampini's data shows no Migs in the air, and we know one was getting fired on, Zampini's research isn't all that it ought to be. Clearer? I pointed that one out as it was more or less the really wierd one. "There were no Migs in the air," "we fired on one," "there were no Migs in the air." I'd take the pilot's word that he fired on one. If Zampini's data doesn't show one in the air his data is incomplete or incorrect. Either way.

From what you've posted you've pretty much confirmed that.

Got it.

Bottomline, I know Diego and he's an OK guy (to debate on the internet anyway) but I wouldn't use his articles on other air wars either based on his research techniques about Korea. Back on a recent tangent from another thread, data on ACIG has been questioned here; the data on ACIG I know has big problems is mainly by Diego, otherwise I don't know.

Joe

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.

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.

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.

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.

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:


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.

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.

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.

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."

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.

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.

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.

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.

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

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

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.

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.

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.

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?


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

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.


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.


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.

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.

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.

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

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...

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.

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.

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.

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.

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.