World War 2 Aircraft Armament

The MK-108 had a much higher ROF than most other 30mm cannons, namely 650 rpm, compared to the heavier 30mm MK-101 with 230 rpm. Compare this ROF to the M2 .50 cal Browning: 450 rpm, making the MK-108 of the Me-262 a faster weapopn than the US build much less potent peashooter.

Late US fighters used the AN/M3 50 Browning, ROF was 1250rpm , the earlier aircraft AN/M2 ran at 850 rpm. Only ground guns ran that slow.
 
Many of the Italian aircraft were equipped with 12.7mm Breda-SAFAT machine gun, which was more or less a copied M2

the Italian 12.7x81mm was less powerful

WW2aircart1.jpg

US 50 Browning was 12.7x99mm the 12.7x108 was Soviet 15x96 was German MG151, 20x80RB was MG-FF/M
 
There was some documented 'experiments' regarding the ability of machine guns to shoot down bombers - you know the one that would always get through

Anyhow - the Brits rigged up 4 then 8 machine guns and came to the conclusion that even with the 1150 RPM of the .303 Browning MkII air gun 1000s of hits (4500 was the figure given) were required to reliably down a given twin engined bomber

And the Spitfire with 350 rounds per gun (2,800 rounds) - could deliver the lot in just under 20 seconds - so unlikely to down a bomber in one pass

The weight penalty of the .50 HMG and its ammo was not thought worth the small improvement that it would provide and with 4 guns replacing 8 and with a much reduced ROF again

The HS 404 20mm on the other hand while initially badly managed - ie the long barrel was for cowl mounted weapons but the British simply ported it into a wing mounted system and a delay in buying the design - did deliver a marked improvement on damage and despite issues with the gun it went on to almost totally replace the Browning MkII .303.

Once those issues were resolved by mid war most British aircraft carried 2* or 4 cannon

*The thin wing of the Spitfire made mounting and heating of the outer 2 guns problematic and in general only the inboard mountings were used limiting the Spitfire to 2 Cannon and 4 MMGs (or 2 HMGs)

However the myth of the .50 cal is very likely a result of the US completely ignoring the hard won experience of the British in getting the weapon to work as a wing mounted air gun and instead spending the entire war trying to fix issues the British had already fixed in 41/42

Due to the issues in getting the US M1 and M2 weapon to work reliably the British did not use the US supplied weapons and the US soldiered on with 4 or 6 M2 .50 cals in the majority of their fighters

http://quarryhs.co.uk/US404.htm

So I find that in forum discussions US members dislike the 'unreliable' 20mm Cannon while the British think they were the best thing since slice bread - the main reason being that they are really discussing 2 different weapons.

So with regards to the OPs question - I think for the BoB the British should have tried harder to get the 20mm to work as it was know for some years that Rifle calibre Machine guns simply didn't cut it any more

The use of the Mk 108 might seem foolish given its weight, low ROF and ammo supply but when you consider the damage it caused to 4 engine bombers from a single hit - it does make sense

Perhaps a mixed armament - 4 lighter cannon for Air to Air (not to be recommended in a ME 262) and 2 Mk108s but with a greater ammo supply per gun although you then run into problems with the sights etc due to the differing trajectories
 
What do we think of the lightly armed Italian and Japanese fighters?

The Japanese fighters were lightly armed. A6M Zero isn't terrible for a 1941-intro fighter with 2x.303 mgs and 2x20mm cannons, but look at the Nakajima Ki-43 Oscar's twin 0.50 cal. And don't get me started about the woeful defensive armament of their multi-engine bombers.

The Italians weren't much better. The Fiat G.50, Reggiane Re.2000 and Macchi C.200 have two 0.50 cal mgs.
 
There are many reasons for an Me-262 to have the ability to combat light fighters. Not the least of which was the American doctrine of sending their fighters far ahead of the bombers to sweep the skies. The Me-262 could be caught by fighters while climbing to intercept in a low energy state. The Me-262 could in fact be pursued on close footing by late model P-51D-20 fighters if the Mustang were on war emergency power. The Me-262 had famously unreliable Jumo 004 engines, and if there were to malfunction even just the smallest amount the aircraft would not be able to out-speed Allied fighters.

In reality that was indeed the main problem of the Me-262 and other first generation jets, though that would reflect an afterthought, so is quite irrelevant, sicne the jet was specifically designed to speed up the aircraft in order to outpase the piston engined fighters and get at the bombers. That missionprofile still requires hard hitting weapons, able to bring down a heavy bomber with a few shots and not focussing on fighters at all.
 
Late US fighters used the AN/M3 50 Browning, ROF was 1250rpm , the earlier aircraft AN/M2 ran at 850 rpm. Only ground guns ran that slow.

That is the problem in itesle, as you mention correctly: "Late US fighters", which in this case were post war build ones, like F8F and F-86 Sabre. In WW2 the US still used the older marks of .50 cal machinegun, as it was their most common weapon of choice, not because it was the best available weapon. (British 20mm guns were also available, though the US armaments industry was already massproducing US types at the time.
 
Technically speaking, wasn't the Hispano-Suiza a Swiss gun (Birkigt) with a locking device invented by the American, Carl Swibilius, which barely got, at the last moment, the non-cockney sounding Chatellereaux loader from France? Could have just called it a British-made gun.
That is the problem in itesle, as you mention correctly: "Late US fighters", which in this case were post war build ones, like F8F and F-86 Sabre. In WW2 the US still used the older marks of .50 cal machinegun, as it was their most common weapon of choice, not because it was the best available weapon. (British 20mm guns were also available, though the US armaments industry was already massproducing US types at the time.
Luckily, all this multiculturalism came to an end after the war when everyone adopted the Mauser 213, and the ADEN, DEFA and M-39 were born.
 
Technically speaking, wasn't the Hispano-Suiza a Swiss gun (Birkigt) with a locking device invented by the American, Carl Swibilius, which barely got, at the last moment, the non-cockney sounding Chatellereaux loader from France? Could have just called it a British-made gun.

Luckily, all this multiculturalism came to an end after the war when everyone adopted the Mauser 213, and the ADEN, DEFA and M-39 were born.

The 20mm hispano was indeed originally a Swiss manufactured weapon, though widely used in other nations, produced almost everywhere under license, especially in UK, USA and France (until occupied by Germany at least). US aircraft simply continued to use the smaller machineguns, as that suited their needs in mainly anti fighter warfare, rather than needing weapons to defeat heavy bombers, as the enemies lacked that sort of aircraft mostly. High rate of fire MG's do well against nimble fast fighters, but less against strongly build armored aircraft, such as heavy bombers. (Hence the need for explosive shell power in the Luftwaffe and Japanese aircraft, as they did face heavily protected large bombers.)
 
How about two 15mm Besa heavy machine guns replacing six of the Hurricane's .303s. Not great I know as they're heavy brutes but as a stop gap adopted during the Battle of Britain due to the problems with the 20mm cannon. The two remaining .303s would be used for aiming as they later were with the 40mm guns in the desert.
 
So with regards to the OPs question - I think for the BoB the British should have tried harder to get the 20mm to work as it was know for some years that Rifle calibre Machine guns simply didn't cut it any more
What the RAF had put into action pre-war was two x4 20mm cannon armed fighters with the original 60 round drums. These were the Westland Whirlwind and the Bristol Beaufighter. The Beaufighter's crewman could replace the drums (but not in combat manoeuvres if he wanted to keep his fingers) and Martin Baker projected x4 belt fed Hispanos in a single bank of 4 with the outers pushed forward of the centre 2 to give room for the belts. Had production continued this would have been the new standard with vastly improved ammunition capacity. As a back up against Hispano production they also did a x12 .303 in the nose. Trials suggested the concentrated ROF of 12 x.303 in a less than 3' circle would saw off a wing or fuselage in one pass. The Beaufighter was still being used by the RAF and USAAF over Western Europe into 1945
 
How about two 15mm Besa heavy machine guns replacing six of the Hurricane's .303s. Not great I know as they're heavy brutes but as a stop gap adopted during the Battle of Britain due to the problems with the 20mm cannon. The two remaining .303s would be used for aiming as they later were with the 40mm guns in the desert.

Heavier than a 20mm Hispano 125 pounds v 95 , slower firing 450rpm v 650 rpm, a shell that weighed about half as much 75 gram v 130 gram and didnt get into production till too late June 1940.
 
Belgian Hurricanes were fitted with 4 .50 FN/Brownings, probably as good as anything, but there's not much feedback on service. The Soviets played with Hurricane armament due to dislike of the popguns, and created a ground attack variant with 4 ShVAK 20mm, 2 ShKas 7.7s and 6 puny rockets. Every increase in armament weight reduced the performance and in the case of the Hurricane, there wasn't any to spare. The more powerful Mk. II Hurri with 4 Hispanos had similar performance to the Hurri Mk.I, meaning that performance of a Mk.I cannon fighter
How about two 15mm Besa heavy machine guns replacing six of the Hurricane's .303s. Not great I know as they're heavy brutes but as a stop gap adopted during the Battle of Britain due to the problems with the 20mm cannon. The two remaining .303s would be used for aiming as they later were with the 40mm guns in the desert.
would have been inadequate
 
Heavier than a 20mm Hispano 125 pounds v 95 , slower firing 450rpm v 650 rpm, a shell that weighed about half as much 75 gram v 130 gram and didnt get into production till too late June 1940.
All of which is why I said it would be a stop gap and the weight is why I had it replace six of the .303s. They would have more chance of defeating armour than the .303s though.
 
All of which is why I said it would be a stop gap and the weight is why I had it replace six of the .303s. They would have more chance of defeating armour than the .303s though.

Probably better fitting 4 or 6 Vickers .50 HMGs they were in production early enough.
 
For anti bomber missions, without 20mm explosive, $which is better? Armor piercing or incendenary ammo?
 
That Browning action went all the way up to 20mm with the Japanese Ho 5, 950 rpm, using the 20x94 round.
It went up to 30 mm if you count the prototype Ho-155 cannon, and it worked very well at that caliber too, just compare the Ho-155 to the MK108.
What do we think of the lightly armed Italian and Japanese fighters?

The Japanese fighters were lightly armed. A6M Zero isn't terrible for a 1941-intro fighter with 2x.303 mgs and 2x20mm cannons, but look at the Nakajima Ki-43 Oscar's twin 0.50 cal. And don't get me started about the woeful defensive armament of their multi-engine bombers.

The Italians weren't much better. The Fiat G.50, Reggiane Re.2000 and Macchi C.200 have two 0.50 cal mgs.
The late-war best Japanese fighters (later variants of the Ki-84, N1K2-J, Ki-100, and the planned A7M) had armament almost equal to the 4 Hispano's of British aircraft. The later variants of the K-84, the N1K2-J, and the A7M2 had 4 Type 99 cannons (license-built Oerlikon FF's), the planned A7M3 would have had 6 of these, and the Ki-100 had 2 12.7 mm machine guns as well as 2 Ho-5 cannons (scaled-up Brownings, these were more powerful than the Type 99's). Finally, the Ki-84 Hei bomber destroyer variant was planned to use 2 Ho-5 cannons and 2 30 mm Ho-155 cannons (further scaled-up Brownings), giving it more firepower than almost any fighter outside the Luftwaffe.

As for the Italians, they didn't improve nearly as much but they were getting there. The Fiat G.55, Regianne Re.2005, and Macchi C.205 (the 3 "next-gen" Serie 5 Italian fighters at the time of Italy's surrender) were all planned or built with 3 MG151 cannons, 1 in the engine vee and 1 in each wing, and 2 cowl-mounted 12.7 mm machine guns.
For anti bomber missions, without 20mm explosive, $which is better? Armor piercing or incendenary ammo?
Pure armor piercing is useless against aircraft with self-sealing fuel tanks; it just goes in one side and out the other without doing much damage. The main use for armor-piercing high explosive ammunition against aircraft was to get the round's explosive charge inside the aircraft, where it would do more damage once it detonated. Without explosive filler, incendiary is the best ammunition by far.
 
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