Why no heavier RAF machine gun calibres? (2 Viewers)

Engineman said:

Nope, I don't accept that it was impossible to develop a good working MK 213 C clone in a shorter timescale. The industries were dragging it out for £££ ($$$).

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You forgot Francs.
It was a multi nation industrial conspiracy
Each nation's gun guys betting the other nations gun guys don't stab them in the back and offer a working gun for a lucrative contract before they do.

Somebody had mounted an electric motor under a Gatling gun before 1900 (V belt). Didn't mean it was a viable aircraft weapon system.

US Navy and US Air Force didn't agree on guns for a number of years and both had several different weapons development programs.

Shortround6 said:

You forgot Francs.
It was a multi nation industrial conspiracy
Each nation's gun guys betting the other nations gun guys don't stab them in the back and offer a working gun for a lucrative contract before they do.

Somebody had mounted an electric motor under a Gatling gun before 1900 (V belt). Didn't mean it was a viable aircraft weapon system.

US Navy and US Air Force didn't agree on guns for a number of years and both had several different weapons development programs.

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Not forgotten, nor the Ruble, ultimately the DM and possibly other copy nations.
Dither, financial-gain delay and political procrastination have marred many technical developments.

Eng

If there is a serious argument being made for Merlin engined Mustangs in the Battle of Britain then surely the same argument means the P-40 and that daft engine the "Allisson" should never have been produced, Merlin Mustangs all the way chaps. If the RAF were somehow remiss in not attacking the Pas de Calais in 1940, imagine how remiss the USAAF were having to ground their P-47s in 1943 because their radios didnt work, over the Pas de Calais. At least the dumb Briish did have an operating air defence system in 1940 which would have been a great help at Pearl Harbor in 1941.

And with that gentlemen, I will take leave of this flag waving BS, it has been a blast, but now I will move on. Have a great New Year and great lives.

Engineman said:

Dither, financial-gain delay and political procrastination have marred many technical developments.

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In general, yes, but in this case I really think it's more that the world was very war weary, there was a massive backlog of non-military investments (like rebuilding much of Europe and Japan, etc.), and there was a huge surplus of perfectly OK military equipment. Only the highest priority military investments like nuclear weapons and jet engines were urgently funded. Aircraft guns, while by no means perfect, very evidently considered good enough for the time being?

Shortround6 said:

It was a close run thing.

You can't build Spitfires because you need Defiants?
You can't build Whirlwinds because you need Lysanders?
Reasons for building Botha's defy Logic.
A lot of the tank story.
The Idea that tanks and AT guns shouldn't have HE ammo, even a little bit.
The 100lb Anti-sub bomb?

I suspect German agents

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Compared to the crap the US was equipped with at the time Bothas, Defiants and Lysanders were in frontline service the British procurement program was a stunning success. American would have gone to war in 1940 with the Douglas B-18, the P-35, the P-36, various USN biplanes and the most pathetic tanks in the world. Even the ludicrous 37mm antitank gun wasn't in service.

z42 said:

In general, yes, but in this case I really think it's more that the world was very war weary, there was a massive backlog of non-military investments (like rebuilding much of Europe and Japan, etc.), and there was a huge surplus of perfectly OK military equipment. Only the highest priority military investments like nuclear weapons and jet engines were urgently funded. Aircraft guns, while by no means perfect, very evidently considered good enough for the time being?

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Indeed. Britain made much use of German POWs in the later 1940s to demolish and clear rubble and rebuild infrastructure with so many male workers still in uniform. Just housing and feeding the population was a struggle with the civilian rationing being at it's tightest in 1947 not 1944 then the disaster of the uniquely cold winter of 1947 which killed off crops and livestock for the rest of the year and almost halted coal production upon which industry and civilians relied entirely for power and heating. Then came disastrous flooding when the snow finally melted after months of snowfall settling. Running alongside was the lack of dollars to buy food from the USA which was a major pre war import. It was no wonder that Rolls Royce got the go ahead to sell Nene jets to the Soviet Union for dollars once they established that these were not on the secret list and the Treasury was urging them to go ahead. It was all very well finding that the wartime rationing had increased the health of the population at large but in 1947/8 there was a real risk of malnutrition. Special measures had to be taken to ensure pregnant women, nursing mothers and young children got vital supplements from the State. Even in 1944/5, with infantry numbers falling increasingly short, 10% of new conscripts did not enter the armed forces at all but were diverted into the coal mines.

There were more urgent day to day needs than fancy aeroplane cannons. American members may have little appreciation of how bad the situation was in Britain post war. Rationing ended in the later 1950s and even steel was in very short supply with many industries relying on reusing scrap and rebuilding old machinery. My mind still boggles at the decision to build four (yes there were four) unassociated strategic nuclear bombers at the same time and order three of them into production. Getting a large rotary aeroplane cannon up to speed when you have perfectly good, if smaller, cannon rolling off an existing production line was sensibly left on the back burner.

z42 said:

In general, yes, but in this case I really think it's more that the world was very war weary, there was a massive backlog of non-military investments (like rebuilding much of Europe and Japan, etc.), and there was a huge surplus of perfectly OK military equipment. Only the highest priority military investments like nuclear weapons and jet engines were urgently funded. Aircraft guns, while by no means perfect, very evidently considered good enough for the time being?

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We are covering a fair bit of time and then we have different countries have different requirement standards.
In 1946-47 there was a huge slowdown in production although studies of some German weapons were done.
In The US in 1946-47 the Armor Research Foundation got a contract to study one of the German MG 213 guns. This was known as the T74A which lead to the T-74B which lead to the T110 of 1949. The gun was flipped upside down (gun fired at 6 o'clock instead of 12 o'clock) and other changes, They also changed from the German steel cases to Brass cases and use US projectiles. This gun was turned into the T150 and later T160 which used the 20 X 102 cartridge and it was this gun that was trialed in Korea in 1952/53.
The 20 X 102 cartridge was by way of the T160 gun (5 chamber revolver) using the old US .60 cal machine gun round (never actually used in service). The T160 became the M39 and was not considered totally debugged until 1959 despite being used in the F-86H, the F-100, the F-101. The F-5 came a bit later.
The US Navy had gone it's own way and adopted it's own gun/s and cartridges in 1940s/50s and the two services didn't really get together until the M61 Vulcan gun.

Now in the US some of the lack of interest in the MG 213 may have been because the USN, not liking the .50 cal Browning had several companies working on new version of the Hispano gun during WW II, which wound up close to the British MK V. But not exactly. These lead to the M3 in 1945, the M24 in Nov 1947 (electric primed) and a different path Hispano gun that lead to the T34 series of guns that lead to a modified cartridge that used a lighter projectile at higher velocity which lead to the Navy MK 12 gun in the early 50s which used a larger cartridge case, a lighter projectile, electric priming and a rate of fire of 1000-1100rpm from a 42kg gun. It gave quite a bit of trouble in the F-8s, less trouble in some other installations.

This is a short, condensed version (I have skipped over some projects and experimental cartridges) of US aircraft cannon development after WW II. They were not sitting on their hands waiting for prices to go up in the late 40s or 1950s.
There was also some cross over with some US projects using British 30mm ammo in the early 50s.
Maybe the Germans had lower standards, understandable when you are being bombed. But the idea that the MG 213 was just about fully developed and ready to go in 1945 does need a large dose of salt.

Reluctant Poster said:

Compared to the crap the US was equipped with at the time Bothas, Defiants and Lysanders were in frontline service the British procurement program was a stunning success. American would have gone to war in 1940 with the Douglas B-18, the P-35, the P-36, various USN biplanes and the most pathetic tanks in the world. Even the ludicrous 37mm antitank gun wasn't in service.

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Aw c'mon. We hadda have something better than the Botha.

PAT303 said:

Do you know much about firearms?, as an example both the Lee Enfield and Mauser rifles are unable to be fired unless the bolt is in battery, or in other words locked, there's a pretty important reason for that.
As for the Hispano itself the cannon armed squadrons that had them in the BoB were so frustrated about the reliability of them, or lack there of that they exchanged them for war weary .303 Browning armed models. Simple fact is HMG's and Cannons were not mature weapons in 1940.

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There was nothing wrong with the weapon itself: the Hispano cannon was designed to fire through a propeller hub, with the cannon mounted in the fuselage and the barrel supported by an engine block. Mounting it outboard, in the relatively flexible Spitfire wings led to the problems encountered by 19 Squadron. Once the mountings were perfected in late 1940 - early 1941, the weapon system was perfectly serviceable.

MiTasol said:

Yep - so much better that it never went into production.

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That's an oversimplification if ever there was one. Testing showed that the Spitfire III was a real improvement over the I, but it didn't get into production primarily because the production drawings and strengthened wings intended for the III were destroyed, when the Germans bombed the Woolsten factory in September 1940. In addition to that, the Merlin X initially used on the prototype was experimental and the XX intended to be used by production IIIs, was later reserved for the Hurricane II series.

In the meantime, development of the Merlin 45 (an XX with the low altitude supercharger blower removed) led to the development of the VA & VB series: the VC series adopted several features of the Spitfire III, while the second Spitfire III prototype was later fitted with the first two-stage, two speed Merlin 61 and, in effect became a prototype for the Mk IX.

Engineman said:

If they had had a working MK 213C with HE instead of 0.5's, all of those damaged Mig's would have been kills.

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Or just make the Hispano to spec and used it?. By mid war it was a very reliable gun.

NZTyphoon said:

That's an oversimplification if ever there was one. Testing showed that the Spitfire III was a real improvement over the I, but it didn't get into production primarily because the production drawings and strengthened wings intended for the III were destroyed, when the Germans bombed the Woolsten factory in September 1940. In addition to that, the Merlin X initially used on the prototype was experimental and the XX intended to be used by production IIIs, was later reserved for the Hurricane II series.

In the meantime, development of the Merlin 45 (an XX with the low altitude supercharger blower removed) led to the development of the VA & VB series: the VC series adopted several features of the Spitfire III, while the second Spitfire III prototype was later fitted with the first two-stage, two speed Merlin 61 and, in effect became a prototype for the Mk IX.

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While the term 'low altitude blower " is often used I thinks it a bit confusing as it implies a separate device whereas in fact it is simply a Merlin XX without the two speed gearbox.
I believe the universal wing introduced on the VC was developed for the MK III.
The destroyed drawings would also explain why the Mk III numbering system never showed up on the Mk VIII.

PAT303 said:

Why would Mk VIII blueprints have Mk III part numbers on them?.

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You claimed the Mk VIII was a production version of the Mk III.

As I explained in detail (and repeat below in italics) if ANY Mk III part was used on ANY later version it still keeps the Mk III part number. REGARDLESS of the later model it is used on.

My apologies to other members for the use of bold and larger print but it appears that a certain person is not capable of comprehending unless things are spelt out in minute detail and bold or large print may assist their comprehension.

Given the Mk III was the first to use a retractable tail wheel, and the Mk VIII was the first PRODUCTION model with a retractable tail wheel, if ANY part from the Mk III was used on the Mk VIII then those Mk III parts would show on the blue prints with Mk III part numbers. Instead you will see that the part numbers on the Mk VIII stern have no previous model part numbers in the circle and that means these are all parts first designed to fit the Mk VIII.



If you study the other drawing from the previous post enough to comprehend what you are looking at you will see that most of the parts on the frame have Mk I part numbers (30027 over x with x being the individual component part number)



and the rest either have no prefix in the circle meaning 35927- followed by the number in the circle. In this case


35927-515 is the part number of the frame pressing before all the other individual components are attached and a small number of parts have 37927 as the prefix meaning they were first designed for the Mk XIV but installed on all Mk VIII aircraft after a specific serial number which is identified by Note 7..





From the earlier post :-

Each Mark has a model number. The Mark 1 was the Model 300. All Mk 1 parts, other than standard parts or parts used on earlier Supermarine aircraft has a part number that consists of the model number followed by a two digit area code followed by a dash followed by an item number.

Taking the fuselage (area 27) as an example Frame 5 is shown on multiple sheets and on sheet 26 the upper port engine mount fitting is item 130. This makes the part number of that fitting 30027-130.

Each part on every later mark that is carried forward from the previous Mark/model keeps the same part number so every mark that uses the same engine mount fitting as on the Mk I has the same part number.

When the part is replaced on a later mark it gets a new part number starting with the new model number, followed by 27 indicating main fuselage and a new dash number.

The Mk VIII is the model 359 so the fuselage is part number 35927. The Mark XIV was model 379. I do not know what model the Mk III was

This is a typical drawing section for the late Mk VIII fuselage which is also used on the Mk XIV. Note all the part numbers start 300 or 379 (meaning a part changed for the Mk XIV but now also used on the Mk VIII) Note also the main frame pressing has only 515 shown as the number. That means it was a new part first used on the Mk VIII and its part number is 35927-515 regardless of which mark that part is used on.

There were a number of things wrong with the Early 20mm Hispano installation on the Spitfire.
One that has not been mentioned so far is that on the Is, IIbs and Vbs the cannon were rolled 90 degrees onto their sides. The 60 round drum was outboard of the gun and the was an ejection chute that lead from the "bottom" (now inboard side) of the gun to slot in the bottom for the cartridge cases to drop out. In the French aircraft (or the first 400 Beaufighters)
the guns were mounted upright and the fired casings exited the "bottom" of the gun. French probably rolled the guns in the Bloch 152.
So instead of the shells going into the breech of the gun down under gravity (unless the plane was pulling negative G) they were coming out of the magazine with gravity trying to pull them sideways. Once fired instead of going out a hole/opening in the bottom of the gun and gravity taking them away, they had to make a 90 degree turn in a sheet metal chute before falling away.
In the later belt feed gun installations the guns were turned upright and the feed/de-linker presented the rounds into the top of the gun.
can't help but think that turning the gun on it's side didn't cause some of the Jams.

MiTasol said:

You claimed the Mk VIII was a production version of the Mk III.

As I explained in detail (and repeat below in italics) if ANY Mk III part was used on ANY later version it still keeps the Mk III part number. REGARDLESS of the later model it is used on.

My apologies to other members for the use of bold and larger print but it appears that a certain person is not capable of comprehending unless things are spelt out in minute detail and bold or large print may assist their comprehension.

Given the Mk III was the first to use a retractable tail wheel, and the Mk VIII was the first PRODUCTION model with a retractable tail wheel, if ANY part from the Mk III was used on the Mk VIII then those Mk III parts would show on the blue prints with Mk III part numbers. Instead you will see that the part numbers on the Mk VIII stern have no previous model part numbers in the circle and that means these are all parts first designed to fit the Mk VIII.

View attachment 811537

If you study the other drawing from the previous post enough to comprehend what you are looking at you will see that most of the parts on the frame have Mk I part numbers (30027 over x with x being the individual component part number)

View attachment 811541

and the rest either have no prefix in the circle meaning 35927- followed by the number in the circle. In this case
View attachment 811543

35927-515 is the part number of the frame pressing before all the other individual components are attached and a small number of parts have 37927 as the prefix meaning they were first designed for the Mk XIV but installed on all Mk VIII aircraft after a specific serial number which is identified by Note 7..
View attachment 811544


View attachment 811540

From the earlier post :-

Each Mark has a model number. The Mark 1 was the Model 300. All Mk 1 parts, other than standard parts or parts used on earlier Supermarine aircraft has a part number that consists of the model number followed by a two digit area code followed by a dash followed by an item number.

Taking the fuselage (area 27) as an example Frame 5 is shown on multiple sheets and on sheet 26 the upper port engine mount fitting is item 130. This makes the part number of that fitting 30027-130.

Each part on every later mark that is carried forward from the previous Mark/model keeps the same part number so every mark that uses the same engine mount fitting as on the Mk I has the same part number.

When the part is replaced on a later mark it gets a new part number starting with the new model number, followed by 27 indicating main fuselage and a new dash number.

The Mk VIII is the model 359 so the fuselage is part number 35927. The Mark XIV was model 379. I do not know what model the Mk III was

This is a typical drawing section for the late Mk VIII fuselage which is also used on the Mk XIV. Note all the part numbers start 300 or 379 (meaning a part changed for the Mk XIV but now also used on the Mk VIII) Note also the main frame pressing has only 515 shown as the number. That means it was a new part first used on the Mk VIII and its part number is 35927-515 regardless of which mark that part is used on.

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Do you think maybe the reason for the Mk VIII part numbers being original and also being on the Mk XIV drawings could be because they went into production where's the Mk III didn't?, furthermore all the drawings and documentation for it were destroyed in September 1940 so there's no logical reason for any of the prototype Mk III numbers to be used on a later production variants.

Shortround6 said:

There were a number of things wrong with the Early 20mm Hispano installation on the Spitfire.
One that has not been mentioned so far is that on the Is, IIbs and Vbs the cannon were rolled 90 degrees onto their sides. The 60 round drum was outboard of the gun and the was an ejection chute that lead from the "bottom" (now inboard side) of the gun to slot in the bottom for the cartridge cases to drop out. In the French aircraft (or the first 400 Beaufighters)
the guns were mounted upright and the fired casings exited the "bottom" of the gun. French probably rolled the guns in the Bloch 152.
So instead of the shells going into the breech of the gun down under gravity (unless the plane was pulling negative G) they were coming out of the magazine with gravity trying to pull them sideways. Once fired instead of going out a hole/opening in the bottom of the gun and gravity taking them away, they had to make a 90 degree turn in a sheet metal chute before falling away.
In the later belt feed gun installations the guns were turned upright and the feed/de-linker presented the rounds into the top of the gun.

https://ww2aircraft.net/forum/attachments/hispano-feed-mechanism-jpg.113637/

can't help but think that turning the gun on it's side didn't cause some of the Jams.

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It was also needlessly long as it was designed so that the muzzle extended past the spinner unlike the FF/M which used a blast tube instead.

The Spitfire Mk III was the Supermarine model number 330.

Nope. I don't buy the "it was really difficult to copy and improve the MG/MK 213". As I said, the gun was "nearly mature in 1945", in fact in early 1945, and all the functional design and prototyping was done! The main problems were lack of high grade materials-hardly an issue for the USA. I guess that the real problem was a lack of appreciation that a better gun than the 0.5 was required. Is this the same story as why the British stuck with 0.303 and, why didn't the British just fit 0.5's? Anyway, proof of the doctrinal weakness is that you had 1950's F-86's with 6 x 0.5 guns being embarrassed over Korea. I do not think the US Air Force would have allowed that to happen if they had understood the issue properly. Mind you, they then bought into a major fighter programme with no guns!

Eng

This is the US in the WWII period we are talking about. Need I say 20mm HS404? Either the manufacture of an already existing and proven design was beyond our technical capabilities, or there was deliberate malfeasance, or the . . . hmm, can't think of another reason. The fact that we could not/did not just make it to the British specifications in the first place is telling, and then we apparently could not just make the changes the British said were necessary to put it in line with the British manufactured guns, which is also telling.

The debacle that was the US attempt at producing the 20mm HS404 always makes me think of the US torpedo scandal.

I know that it is hard to believe (and admit it when they are from your country) but there are people that incompetent..

yulzari said:

There were more urgent day to day needs than fancy aeroplane cannons. American members may have little appreciation of how bad the situation was in Britain post war. Rationing ended in the later 1950s and even steel was in very short supply with many industries relying on reusing scrap and rebuilding old machinery. My mind still boggles at the decision to build four (yes there were four) unassociated strategic nuclear bombers at the same time and order three of them into production. Getting a large rotary aeroplane cannon up to speed when you have perfectly good, if smaller, cannon rolling off an existing production line was sensibly left on the back burner.

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Britain needed an improved aircraft cannon for jet fighters because we spent valuable resources on having strong and modern armed forces even during hard times after WW2.
The slow development of the 213 into the ADEN 30mm is possibly slightly more understandable, but it would be interesting to see the discussions about the development of the ADEN from the Air Ministry, the RAF and the Armament Development Establishment.

Eng