WWII aircraft armament machine guns and cannon

[Pumpkin]

I would think anything except for maybe an Ilyushin Il-2 Stormovik would have faired very poorly after 6/8 50’s ripped through it.
I’m half British and feel some of the negative talk about the USAAF fighters can simply be traced to the connection with the USA.
Any time spent reading about the P-47 should make someone rethink their criticisms of the 50BMG. As a boy I remember reading, a Fighter Pilot’s Life (Col. Gabby Gabreski) and thinking, what a fantastic fighter, and American!
It’s reputation wasn’t gained from a couple of wings full of 20mm’s.

[Mike Irwin]

Regarding gun heating... I seem to recall that the US Navy experimented with gun heating in some fighters by routing exhaust gas either into or past the gun compartment.

[Mike Irwin]

" I would think anything except for maybe an Ilyushin Il-2 Stormovik would have faired very poorly after 6/8 50’s ripped through it. "

Don't kid yourself about the Sturmovik's alleged invulnerability...

"In his memoirs, Il-2 pilot and Hero of the Soviet Union Valentin Averianov wrote that “despite the fact that the armor offered no protection from 20-mm anti-aircraft rounds and aircraft guns, it still deflected many types of munitions.” (https://www.rbth.com/defence/2014/10...tle_40391.html)

My guess is that his definition of "aircraft" guns is the heavier caliber machine guns and machine cannon (13mm and 15mm) fielded in German fighters, but which were generally not found in ground units.

Sturmoviks also suffered VERY badly in the beginning stages of the war because they tended to attack without fighter cover.

[105kw]

The only time US forces faced Sturmoviks was in Korea, we met IL -10s.
They got shot to pieces by Corsairs, mostly armed with .50s, P-51 fighter/bombers, and our early jets, F-80s, F-86s.
The Communist forces quit flying them during daylight operations.

[Pumpkin]

Great information.
The last paragraph sums up the Russian military’s views regarding tactics and the value they placed on their peoples lives…

“To their surprise, the German POWs immediately pleaded for their lives, having been told by their political officers that the Il-2 were crewed by maniacs who enjoyed tormenting prisoners between missions. Maniacs, they were told, because normal people cannot fly over a battlefield through anti-aircraft fire at an altitude of 100 meters”
Edit:
The example of the II-2 was only used because of it’s defensive armor plating compared to contemporary attack aircraft of the day. I’m pretty sure a Fairy Battle, Hurricane MkIID, Ju-87, HS 129, Dauntless, etc. if used in the same manner would not have faired any better.
Incidentally, I don’t have a particular soft spot for the II-2.

[Mike Irwin]

The Sturmovik was largely protected from Germany's 7.92 machine guns that formed the core of the anti-aircraft defenses of most German units.

The other aircraft mentioned were a lot more vulnerable.

[44 AMP]

The example of the II-2 was only used because of it’s defensive armor plating compared to contemporary attack aircraft of the day. I’m pretty sure a Fairy Battle, Hurricane MkIID, Ju-87, HS 129, Dauntless, etc. if used in the same manner would not have faired any better.

The Sturmovik was heavily armed, with a set of 23mm cannon, exceptionally well armored, and fairly fast, making it a difficult target to shoot down.

Many Luftwaffe pilots reported frustration seeing their shells "bounce off" the heavily armored aircraft. But, it did have an Achilles Heel. The oil cooler was vulnerable on the belly of the airplane and once that became known to the Luftwaffe fighter pilots, Sturmovik losses increased considerably.

Of the other planes mentioned, the Fairey Battle was obsolete even before the war began and their use in the Battle of France resulted in devastatingly high losses.

The Battle, and the Stuka and even the Val all shared the same problems, as did later designs, though to lesser extent, they simply could not survive unescorted, against enemy fighters.

The Dauntless and the Hs 129 were radial engined, and radials are generally more resistant to battle damage than liquid cooled inline engines. Also the 129 was well armored to resist light ground fire.

The 23mm auto cannon arming the Il-2 are an interesting weapon, apparently an original Soviet design, firing a higher velocity round (listed as 900 m/sec MV) but with a firing rate of only 600 rpm (by the listed specs) fine for ground attack, a bit less so for aerial combat.

[davidsog]

World War 2 Fighter Armament Effectiveness

The American Browning .50 M2 is an undistinguished performer, particularly when compared with its closest competitor, the 12.7 mm Berezin.

To sum up, the preferred US armament fit was effective for its purpose, but not very efficient by comparison with cannon.

The outstanding performer is clearly the German 30 mm MK 108, which achieves ten times the destructiveness of the .50 M2 for only twice the weight.

It is worth pointing out that for as long as the battery of .50s proved adequate against the targets usually encountered, there were strong arguments in favour of retaining the weapon, as the standardisation of production, supply, maintenance and training provided great logistic benefits by comparison with the plethora of different weapons fielded by the Germans and Japanese in particular. Of course, the USA did make some use of the 20mm Hispano cannon, but this was severely limited by production problems: that is another story, told elsewhere in this book!

https://flying-guns.com/world-war-2-...effectiveness/

[Sharkbite]

Guys, i cant thank you enough for the history of flying machine guns.
Being just a simple Ground pounding Marine the above ground stuff is fascinating. Thanks again.

[44 AMP]

The outstanding performer is clearly the German 30 mm MK 108, which achieves ten times the destructiveness of the .50 M2 for only twice the weight.

I am unclear if the author is referring to the gun or the individual projectile weights as "only twice" as much.

The "infallible" Wikipedia reports the cyclic rate was 650rpm. but accounts from Luftwaffe personnel say it was much slower than that, and Allied pilots reported the sound of the gun, the rate of the "thud, thud, thud" indicates something in the 400rpm +/- range.

Everyone seems to agree on the fact that it was a low velocity round, at about 500m/s which works out to be in the 1600fps range.

The low velocity and the resulting arc of trajectory made the gun quite difficult to make hits with, so while on a shell per shell comparison the 30mm is quite more destructive than the .50 (though I have my doubts about 10x more destructive) getting hits was much more difficult, and its effective range was short.

Additionally, in the ME 109s armed with the Mk 108 30mm, the gun was charged pneumatically. and the air bottle held enough for two, possibly three charges. another thing that did not endear it to Luftwaffe pilots, as the gun (reportedly) jammed frequently.

In the 109 with the 20mm "engine cannon" charging was electric, so the guns could be recharged as often as needed.

And, on this point, I need to mention that there is a difference between charging the gun, and firing the gun. They are separate functions, even if combined in one assembly, it is two different systems which act independently of each other.

Charging the gun, using what ever system, is pulling the bolt to the rear, where it locks with ammo positioned to feed into the chamber when the bolt goes forward. Firing the gun from the cockpit trigger activates the mechanism that trips the internal mechanical sear of the gun, releasing the bolt to go forward and fire, mechanically.

[Pumpkin]

Frequent comparison between the ME-262 and the F-80 come down to the weapons each plane had. As previously mentioned, the 262’s 30mm had a MV of about 1600fps. The F-80’s 50BMG was up close to 3,000fps if my math is correct.
If both planes were equal (and I don’t think they were) the pilot of the 262 would have to have been not only a better pilot but also a better shot.
The 30’s low velocity combined with a more than likely low ballistic coefficient would have resulted in a rainbow trajectory. Not the best time to be spending a lot of time estimating your enemies range. The high velocity 50 in my opinion would have been much more forgiving in these areas.
Some would argue that the 262 was built as a bomber destroyer which is true but it was what it was and I feel that the F-80, had they met, with its puny 50 cals would have cleared them from the sky, as well as bing able to shoot down any German bomber (had there been any)with ease.

[105kw]

P-80s were in Europe at the end of the war, but saw no combat.
Me262s were good aircraft, but were out numbered by a huge margin by allied fighters.
The Mk108s were low velocity, and the gunsight in the 262 wasn't really good in a turning fight due to trajectory, and lead factors.
And, if they could get a 262 to turn, allied fighters could engage.
British Spitfires, Mk9, Mk16, and Mk14, as well as Tempest Mk 5s all had success against German jets.
Our P-51s, and P-47s did well too.

[bamaranger]

Oh yeah, WWII fighter planes are one of my things. So here goes.

The Brits put the 8 gun Hurries and Spits up in the Battle of Britain, and they held their own, but their was a lot of criticism of ineffectiveness of .30 cal fire, especially on the medium Nazi bombers. Somewhere in my library I have a pic book of shot down Nazi aircraft from the Battle, and many are simply riddled with hundreds of holes. The Brits went with a 12 gun wing for the Spit and Hurri which was not widely used as they were developing the dual 20mm and 4-.303 versions at about the same time. Their were even some .50 cal spits as well. The Spits problem was the narrow wing. Look for the bulges on the wings of cannon spits. The fatter wing of the Hurry could take the 20mm guns more easily. But which 20mm gun to adopt was an issue....reliability.

As the war progressed, the German pilot became more and more of an interceptor of bombers and the German aircraft went with cannon to address the durability of the US four engine bombers. They were essentially confirming what the Brits had learned with the .303 facing the twin engined medium Nazi aircraft in the Battle.

Gun harmonization was a thing. If you had your own aircraft, and the crust to order it, a pilot could spec to his chief how he wanted the guns arranged. But not everybody had their own plane. More common was arranging the guns to impact in pairs at 200-300-400 yds etc, creating a beaten zone so to speak ahead of the aircraft. This allowed a margin of error for pilot skill and lead estimation, etc. There is some very good info online these days regards this topic. A certain 'Tube channel does a very good job discussing same using manuals and graphs etc....fascinating. I believe the provider calls his channel US Bombers, and he addresses many of the topics we're discussing here.

The P-47 was an 8 gun, .50 cal machine, but later in the war as the 'Bolt took on more ground attack, two 50's were often deleted to allow the attachment of bomb brackets. and bomb load. The 8 gun version was much preferred by the pilots.

Seems I read an account of a Navy pilot saving two guns for his flight back to the carrier......I think this was in the F4F Wildcat.....might have been in the F6F, but it was the only instance I recall of reading same.

At least in the Euro theater, the use of tracer ammunition by both fighters and bombers had declined by the end of the war. Fighters believed that if you missed with your first burst, there was no trace to alarm your target he was under fire and you might get a second shot. It was believed some bomber gunners were prone to not aim but try and adjust their fire by tracer and there was not time for that, aimed fire was better. Their are documents related to the decline/desist in bomber tracer ammo. Their was also a "headlight" project, where extra bright tracers were issued to gunners to intimidate attacking aircraft, but the project was deemed ineffective.

Likely the best gun setups were the nose mounted 4-.50's and a 20mm in the P-38, and the similar fuselage mounted 4x20mm and 4-.303 of the Brit Mosquito. No harmonization problem.

The German Mk108 30mm was criticized by some pilots by its slow rate of fire. Combined with the ME262 high attack speeds, some pilots (Galland maybe) said you could miss even with a correctly aimed burst, the target flew between the rounds!!!!

There is a huge amount of WWII gun camera footage online now, and I have spent way to much time watching a lot of it. Interesting points....P38 footage is recognizable by the concentrated impact and centralized fire. P38 footage early in the war is bad, the gun camera's were nose mounted and vibration spoiled images. The cameras went to a wing and footage got better. The best P38 air to air film I ahve seen was was recorded by a pilot last name FRIEND against a Me109.....devasting. Must have been a heck of a fight, a P-47 and a second P-38 are all visible in the footage. Someday, I will see a P-38 in the flesh, just haven't yet. I would even settle for a static display.

The Germans had a timed fuse in some of their air to air cannon ammo...you can see rounds that missed air burst "down range" of aircraft under attack. In this manner, German fighters were not lobbing explosive rounds down on their own territory. Much of this type footage is seen when a German aircraft is attacking a US heavy bomber......always hard to watch....10 brave but terrified guys in there.

By the late Euro theater, air to air combat becomes rare and a lot of gun camera footage is air to ground. But the 1943-early '44 footage has a lot of air to air combat.

All for now...........

[105kw]

The second model of the Hurricane, was the Mk2. In the B mod they went to a 12 gun set-up, 2 guns outboard of the normal 4 in each wing. The Mk2c had 4, 20mm with about 90 round per gun, it was introduce in late spring 1941.
The Spitfire stay with 8 gun wings, although they made Mk1b, and Mk2bs with 2, 20mm cannon. They had jamming problems, which get solved by the Mk5. The main problem with the Spitfire was 60rd drum magazines, giving about 6 seconds of firing time. This was only changed with the Mk5c, which used 120 box feeds.

[Pumpkin]

What a time for innovation WWII was!
FW-190's with engine control computers,
Bi-plane fighters (Gladiators, Fiats) to Jet and rocket powered fighters,
Wide use of engine boosting, super and turbo charging, and Nitrous for emergency power.
Tricycle undercarriage, the use of STOL aircraft by all sides,
B-29 crews in Tee Shirts at high altitudes, the list goes on...

One burning question, speaking of armament.
Why did the Brits choose to not have ventral gun positions on their bombers? I believe one version of the Lancaster might have had a token ventral gun position.

I have yet to read a valid reason for justifying this, every other country it seems had some sort of gun position even on earlier designs (gondola, dust bin, small opening) for at least one MG.
This seems to be an especially bad decision with the German Bf 110's and He 219's that employed the upward firing Schräge Musik cannon armaments. How could No Deterrent have seemed acceptable!
Maybe it was the same decision makers the told Frank Whittle to go to the pub and nurse some bitters with his turbojet invention in 1930!
Seems £60,000 was too much to spend on such a daft idea.

[Mike Irwin]

"exceptionally well armored"

Well... compared to its contemporaries, yes.

Exceptionally well? No, not really. It was armored. It gave it some resistance to some ground fire.

But it was not, as the legends that built up around it, a flying tank, impervious to anything the Nazi could throw at it. Yes, the armor made it more difficult to bring down, especially to ground fire.

The maximum armor thickness on the Il-2 was 12mm. A half inch. That was, as I noted above, enough for it to withstand RIFLE caliber bullets.

That half inch of armor was not all over, though. There simply wasn't much of it, and most of what there was was on the underside. Why there? Because the Il-2 was a ground attack aircraft.

The vast majority of armor on the Il-2 was closer to half that, or 5 mm, or slightly under two tenths of an inch.

And that was, generally, enough to deflect rifle caliber bullets.... MOST of the time.

If the bullet had a steel core (like American black-tip ball ammo for the .30-06), it was not stopping that. At all.

Fortunately for the Russians, the Germans didn't really have that kind of ammo.

The whole "HEINZ! Mein kannonen shells bounced of the Sturmovik!" is... well... sure. It could have happened. But it's FAR more likely that those "bounces" were actually deflections caused by the shell hitting the armor at an oblique angle.

Square hits from the 13, 15, and 20mm guns found on German aircraft were going to give the Russian aircraft a very hard time.

[Mike Irwin]

"The outstanding performer is clearly the German 30 mm MK 108, which achieves ten times the destructiveness of the .50 M2 for only twice the weight."

I've not read the whole article, but I have some serious doubts about the alleged overall effectiveness of the Mk 108.

First, as 44 notes, its actual cyclical rate tended to be a lot lower than its ground test rate.

Secondly, also noted above, its low velocity gave it limited range and a VERY high trajectory.

It also was unable to carry a significant ammo load due to the size and weight of the rounds.

So, given those drawbacks, why was it developed and fitted to German fighters?

To combat heavy BOMBERS.

Aircraft fitted with the 30mm Mk 108 were dedicated to killing American and British heavy bombers.

They were not intended to fight American or British fighters, and the 30mm was largely ineffective against American fighters because of the low rate of fire and the high trajectory, making hits against fast, nimble targets VERY difficult.



"The American Browning .50 M2 is an undistinguished performer, particularly when compared with its closest competitor, the 12.7 mm Berezin."

OK, that I simply don't understand at all. The Berezin was an adequate gun, but it wasn't head and shoulders better than the M2. I'd call that yet another myth, just like the myth of the indestructible Sturmovik.

The Berezin was complex, expensive to produce, and had a number of idiosyncratic issues that made it problematic. Useful, but problematic.

[105kw]

Then other great problems with the Mk108 were magazine capacity, 60rds in the Me109, and I think in the outboard wing guns in the Fw190.

Second, in the Me109 was gun charging, it was pneumatic, using the same bottle that was used from the 7.92 cowl guns in the Me109. For the 7.92 it worked fine, for the 30mm, it only allowed 2 to maybe 3 recharging trys.

The 30mm Mk108 was not very reliable, and if it jambed, you were down to 2 13.2mm cowl guns.
This problem continued until the end of the war. While the factory installation of the 30mm became more common. The Me109K-4 had no other option, only the 30mm.

I had read accounts of Luftwaffe units begging or borrowing every 20mm armed G model Me109 they could get.

[Pumpkin]

Were some of the Luftwaffe gun choices made because they thought US fighter escorts would be spotty?
Too much reliance on heavy bomber destroying cannons?

The P-47 was awesome but couldn’t match the range of the Mustang.

Those first P-51’s must have been a nasty surprise when they showed up so deep in German skies.

[bamaranger]

Getting away from guns, but the "range" issue of the P-51 is over played in much historical narrative. Yes, the P-51's flew long range escort and were effective. But.......there was a trend early in the war by the so called "bomber enthusiasts/bomber mafia" in Europe that the heavy bombers would always get through. There is actual documentation of the Army Air Force higher ups declining money and contracts for drop tanks to give the P47 and P38's the legs they needed to fly longer escort missions.

The P-38 was especially capable of longer range, had it been "allowed" and equipped with drop tanks when it first arrived (and it was the first , arriving summer '42) in the Euro combat zone. Heck, they hedge hopped the P-38's to Europe via Canada/Iceland/Greenland/Scotland with a B-17 navigating! That's how we ended up with the "Glacier Girl" story, a Lightning recovered from the ice in Greenland. A P-38 got the first Euro kill on a Condor flying that route (I think). P-38's ambushed Yamamoto in the Pacific in April '43 on a particularly long ranged flight . To do it, they used mismatched drop tanks, as there were not enough pairs of tanks to allow for all aircraft involved. The P38 could be trimmed out to fly with the odd configuration. That was months before the first P51's arrived in Europe.

Fortunately, some more forward thinknig junior officer began working on drop tank projects despite the resistance higher up. That officer, guy named KELSEY, cracked up the first P38 in a publicity Army Air Corps cross US flight with the only flying version prior US entry, the YP-38, and set the project back several months. Had the brass not attempted that lame brained stunt and direceted KELSEY to fly it, the P-38 could have been in Europe even earlier. KELSEY owed the AAC one and came through on drop tanks.

By the time tanks were approved and available for all fighters, the P51 was refined and long range missions into Germany were on. But the P-38 and P47 could have done it, if the tanks and policy were present.

There's a video on this topic by Gregs Airplanes or something similar.

[davidsog]

30mm was largely ineffective against American fighters because of the low rate of fire and the high trajectory, making hits against fast, nimble targets VERY difficult.

That idea is floated around a lot. On its surface, it makes sense. However, it is just not factual. Mk 108 was absolutely effective against fighters. It was most likely the best air to air weapon devised for a fighter in WWII.

It was point and shoot out to 400 meters, which is way beyond practical firing range in a aerial dogfight.

It had a max ord of only 4 inches higher than the 13mm German aircraft guns and only 2 inches above the MG151 20mm.



Every Vulnerability Study I have seen from World War II, Allied or Axis came to the same conclusion about large caliber rifle rounds. They just were not as effective as cannon. That's no modern fighter uses rifle caliber guns.






The controlled testing from this report measures the results from a zero degree deflection, directly behind the aircraft. The higher the deflection, the higher the probability. That being said, no case can be made that .50 cal was more effective than a Mk108. Our .50 cal was adequate enough to bring down enemy aircraft and we had enough of them to win the war. I would go so far to say it was the best choice for us given the totality of the circumstances when one factors in time and cost to find something more effective. It did the job.

[bamaranger]

The B25 and B26 versions developed as dedicated strafers in the Pacific had to be the most heavily armed aircraft of the war, fielding 12 -14, forward firing .50's controlled by the pilot, and the top turret was moved forward to join the party as well. Some versions of the B25 even got a 75mm cannon!

The Brit Mosquito had some experiments with a 57mm gun, more heavy metal.

[davidsog]

Here is a video of Mk108 testing conducted by the RAF.

https://www.youtube.com/watch?v=91LUxqn1QY0

One round takes the tail off a Spitfire....

[Jim Watson]

An old Gun Digest had an article on oddball US ammo.

There was the Spotlight with a bit of flash powder to show you where you hit. Wiki says that was considered naughty explosive by the Hague boys and that it would show you where you hit but not which way you missed like a tracer.

There was the 16mm Vega which was described as .50 BMG necked up enough to hold a worthwhile HE shell.

Not an aircraft gun, but of interest to the velocity addict, the .30 Medical Museum was .50 necked down to .30 and shortened a bit. Purpose was to simulate the very fast moving fragments from a nearby shellburst.

[Pumpkin]

http://www.generalstaff.org/WW2/Pape...tang_Daneu.htm

Here is a very interesting but long comparison of the P-51, P-47 and P-38 concerning escort abilities. Make of it what you will…

I had always read that the P-38 had a much better time in the pacific but never really studied why. I always assumed it was because of a superior opponent?According to this paper low oil temperatures at high altitudes played a role in high oil consumption and also contributed to turbocharger failure.

Also apparently the P-47 and P-38 also had some issues flying at the same airspeed as the bomber formations.

A chart lists the escort range as about 30% better for the Mustang with drop tanks?

Regarding 1 hit from a 30 blowing the tail off a Spit.
How would the same Spit have faired with a short blast from 6/8 50’s?
A destroyed aircraft is a destroyed aircraft.