British rearmament earlier and more effectively in the 30s

[tomo pauk]

Just a little side idea, were there any anti aircraft guns suitable for tank use at the time? Navy or Army? My memory twlls me the Royal Navy had a lot of gun types in the range being discussed and it might have saved a few Bobs while improving the situation. Sorry Bob.

There was a lot of suitable guns. A number of 6 pdr stuff, the powerful 3pdr Vickers, 2pdr LV and HV. 12pdr guns from the Great War. 13 pdr and 18 pdr gun from the Army stocks.
See here for more ideas.

 

[Foo Fighter]

Thank you, enough there for the job then.

 

[NOMISYRRUC]

Time for a table.

​

Notes

1. Source: The Annual Abstract of Statistics. Unfortunately the figures come from 3 different editions. The third source calculates the National Debt in a different way from the first and second, which is why 31st March 1940 is less than 31st March 1939.
2. Financial years run from 1st April to 31st March
3. Amounts are in millions of Pounds.
4. From 1928-29 to 1936-37 the Total National Debt Service is the "Permanent Annual Charge of the National Debt" under the Finance Act of 1928 and Subsequent Years.
5. In 1937-38 the Permanent Annual Charge of the National Debt was fixed at £224.0 million by the Finance Act, 1937 but a greater sum was met from Revenue.
6. In 1938-39 the Permanent Annual Charge of the National Debt was fixed at £230.0 million by the Finance Act, 1938 and this sum was charged against Revenue. An additional sum of £1,946,010 was from receipts from the Defence Departments under Sec. 1 (5) (b) of the Defence Loans Act 1937.
7. Defence spending for 1937-38 and 1938-39 is exclusive of issues under the Defence Loans Act, 1937 viz

​

 

[NOMISYRRUC]

This compliments the table in Post 85.

​

Notes

1. Source: The Annual Abstract of Statistics.
2. Financial years run from 1st April to 31st March
3. This is net expenditure and doesn't include Appropriations-in-Aid from other departments.
4. Furthermore, 1937-38 and 1938-39 is exclusive of issues under the Defence Loans Act, 1937 viz:

​

 

[JWilly]

in the second case the targets were a lot bigger, generally the range was greater, and the bombers were a lot slower and didn't manoeuvre very much, so there would be more time for fighters to aim at them.

Fighter attacks on daylight bombers were more likely survivable for the fighter pilot if they were diving slashes, or head-ons, or somehow otherwise high-closing-rate, high-angular-rate-of-change...definitely not the case for tail-chase.

A fighter expecting "more time" to aim from a bomber's six was pretty much asking for return fire from whatever guns the bomber crew could bring to bear...and the firing solution for them would be no harder than for the fighter.

A key characteristic of high-closing-rate attacks was the need for high RoF in combination with significant damage per hit.

 

[uk 75]

Something we have not addressed is the activity of Japan and the vulnerability of British possessions in the Far East.
There is much discussion in the period about how to fortify Singapore and how long it would take the Fleet from European waters to arrive.
Appeasement becomes much more hard nosed when one realises that the Conservatives were the party of Empire.
Mussolini and later Hitler were an unwelcome distraction from the task of Imperial Defence.
Japan's invasion of China makes it even clearer how vulnerable Britain is. It also shows the inability of the League of Nations to impose "collective security".
Chamberlain's much derided comment that Czechoslovakia was somewhere about which we knew little or nothing was a practical point. Britain's interests outside Europe were more important than the continental commitment to France.
Oddly Churchill who was an even more ardent Imperialist than Chamberlain was able to see the importance of standing up to Hitler even at the expense of dealing with Japan.
It may be added that Britain failed to appreciate the ability of the Japanese and underestimated what was needed to defend Singapore until it was too late.

 

[Hood]

I think that is slightly unfair, the Royal Navy took the Japanese threat very seriously and a lot of the design decisions and numbers of hulls required were based on the potential Japanese threat.
As Washington broke down and the London Treaty was stillborn it was clear that Italy and potentially Germany would rearm and that imposed distractions and the need to keep more ships at home/in the Med (these could be used to sail west or east as required).

Politically was it likely that Japan would suddenly attack British interests given that it was mostly involved in pushing its sphere in China and Manchuria? Britain didn't even seem to complain much when Shanghai was seized.
An invasion of Malaya was improbable until Japan had managed to penetrate into southern China along the coast and diplomatically bully France and Thailand into opening a direct overland route.
Therefore most defence went into coastal defence (torpedo bombers and the like). Of course they often got the dregs, but by the late 1930s having masses of cool RAF planes in Britain to inspire the population that they could match Germany's masses of cool planes took precedence.

 

[Tony Williams]

Fighter attacks on daylight bombers were more likely survivable for the fighter pilot if they were diving slashes, or head-ons, or somehow otherwise high-closing-rate, high-angular-rate-of-change...definitely not the case for tail-chase.

A fighter expecting "more time" to aim from a bomber's six was pretty much asking for return fire from whatever guns the bomber crew could bring to bear...and the firing solution for them would be no harder than for the fighter.

Don't forget that we are looking at early-war circumstances in this thread. The defensive armament of Luftwaffe bombers in the BoB was pathetic compared with most RAF bombers (and they weren't all that good - .303 only).

Also, data from later in the war concerning the effectiveness of USAAF bomber defensive fire vs. that of escorting fighters revealed that the guns were considerably more effective when used by fighters than when fitted to bombers - about ten times better, in terms of rounds fired vs planes shot down.

 

[uk 75]

What becomes clear during the 30s is that Britain even doubts its ability to win a war with Mussolini in the Mediterranean.
Every report to the Cabinet from the Chiefs of Staff councils against military action.
Of course this was the legacy of the years of disarmament and treaty limitation but as the decade goes on rearmament seems to make little difference to Britain's ability to defend its interests.
Whether it is Italy, Germany or Japan no real thought seems to be given to how we would defeat them in a war. Rather the emphasis is on deterring war by acquiring new weapons notably for the RAF.
Perhaps because World War One had required the US to achieve a decisive result against Germany British planners faced with an isolationist USA simply did not know what to do.

 

[alertken]

1930s' Defence Policy had a formal term: Cunctation (which means waiting upon events): that's not exactly the Do Nothing Option, hoping the problem will go away, but pragmatically means: attend to what you can influence. So: build HMNB Singapore, try to keep Italy on the side of the angels. build Illustrii and KGVs for about 1941 and Big Twin, then Fourmotor Paralysers...all...labour-sparse, because the Electorate will not respond to a call to citizen arms, again, as it made clear in By-Elections, rallies and support such as for the Royal Commission on the Private Manufacture of and Trading in Arms.

Your OP Q was: what could we have done to prevent the European Events of 1938-40. A respectable A is: what makes you think UK could have done anything? 4th-or-so largest Air Force fit, maybe, for tribal pacification, Contemptible Army, majestic Navy, but most Armed Forces did not care. Emerging from a ghastly Depression, every family with memories of Great War loss, maiden aunts in every village, crying 11/11 at the War Memorial: of course Ministers hid behind the Maginot and League Collective Security.

 

[uk 75]

Alertken. Thank you for this elegant summary. I agree that yours is the only realistic answer to my question.

I would add that the UK could not count on any reliable allies.

France as Archibald has described was hobbled by the Daladier and Gamelin factor.

Russia was in the clutches of Stalin who had his own plans for occupying Europe at some point.

The United States was the key absentee. Its absence from the League of Nations doomed that organisation to failure.
Roosevelt could do little to help until Japan attacked Pearl Harbour. The US had its own reasons for wanting to see Britain and France lose their colonies.

 

[GTX]

Time for a table.

View attachment 687953​

Notes

1. Source: The Annual Abstract of Statistics. Unfortunately the figures come from 3 different editions. The third source calculates the National Debt in a different way from the first and second, which is why 31st March 1940 is less than 31st March 1939.
2. Financial years run from 1st April to 31st March
3. Amounts are in millions of Pounds.
4. From 1928-29 to 1936-37 the Total National Debt Service is the "Permanent Annual Charge of the National Debt" under the Finance Act of 1928 and Subsequent Years.
5. In 1937-38 the Permanent Annual Charge of the National Debt was fixed at £224.0 million by the Finance Act, 1937 but a greater sum was met from Revenue.
6. In 1938-39 the Permanent Annual Charge of the National Debt was fixed at £230.0 million by the Finance Act, 1938 and this sum was charged against Revenue. An additional sum of £1,946,010 was from receipts from the Defence Departments under Sec. 1 (5) (b) of the Defence Loans Act 1937.
7. Defence spending for 1937-38 and 1938-39 is exclusive of issues under the Defence Loans Act, 1937 viz

View attachment 687957​

This is a useful table to put things in context. I would also add the following to give an idea of the financial burden being worn during the interwar years just paying off the debt from WW1:


the benefit of hindsight is a wonderful thing but during the late ‘20s/early ‘30s with heavy debt repayments, the Great Depression and the memories of WW1 very fresh in their minds, no one really had either the appetite or ability to consider major rearmament much earlier than they did.

 

[HoHun]

Hi Tony,

Hi Henning! Long time no hear from

I tried to mail you some stuff somewhat recently, but I think I might have used an old email adress

We have to bear in mind that in Europe in general, and the Battle of Britain in particular, there were two types of aerial combat: fighter vs fighter, and fighter vs bomber. In the first case, I agree that there would be no time to mess about with tracers, but in the second case the targets were a lot bigger, generally the range was greater, and the bombers were a lot slower and didn't manoeuvre very much, so there would be more time for fighters to aim at them..

In my opinion, the inevitable aim wander during the time of flight of the projectiles would have made a firing solution "confirmed" with tracers invalid by the time you had optical confirmation anyhow. Not to mention that tracers create all kinds of optical illusions! Have you heard of the Japanese bi-colour tracers, by the way? They change colour some way downrange, probably to counteract these illusions. I think they were discussed on j-aircraft.com forum, if I remember correctly!

Regards,

Henning (HoHun)

 

[HoHun]

Hi Rob,

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to loft a single 20mm cannon. Hispano-Suiza, Klimov and Daimler-Benz were all developing engines that could accommodate a single 20mm motor cannon firing through the prop hub.

I'm not sure what you mean by "loft", but the Me 109 E-3 carried 177 kg of guns and ammunition, which included two 20 mm cannon, while the Hurricane I carried 160 kg of guns and ammunition, so there wasn't much of a difference (and I could convincingly argue it was actually caused by the two German 7.92 mm MGs having an extravagant 1000 rounds per gun ;-)

Admittedly, the Messerschmitt's cannon was very light for a 20 mm cannon, but replacing the Oerlikons with Hispano II's would have increased the total weight by only 50 kg, approximately.

Accordingly, I'd not consider weight a limitation to cannon use on late 1930s' fighters with 1000 HP engines.

Regards,

Henning (HoHun)

 

[Colonial-Marine]

What color tracers did the Japanese normally use?

 

[HoHun]

Hi,

What color tracers did the Japanese normally use?

The "Cartridges, S.A., 20-mm, for Ho-5 A/C Cannon" used red or greenish white tracers in the APT rounds.

The "Aircraft Cannon Cartidges, 12.7-mm Semi-Rimless for Aircraft Cannon Browning Type" also had red, bright red or greenish white tracers, as well as a special type indicated by a pink bullet tip, which burned white before changing to red.

The "Ammunition for the Type 3 Gun (13.2 mm )" has a tracer ball round with an 8 second trace (which I think is excessively long ... probably they were hoping for an incendiary side effect, I guess).

The "Ammunition for the Type 2 Gun (13 mm)" has a yellow tracer with 4.5 seconds trace.

The above information is from the "Japanese Ammunition Leaflets, Section B - Small Arms Ammunition & Aircraft Cannon Cartridiges Up to 20 mm, Kirkee 1945". It mentions more tracer rounds in other calibures, mostly without stating the colour, and in one place it mentions that variants of the rounds exist which only differ in the tracer composition, so there might a considerable variance in tracers! I actually thought I had read about blue tracers too, but that's about the only colour not mentioned in that booklet :-D

https://bulletpicker.net/pdf/Japanese%20Ammunition%20Leaflets,%20Section%20B.pdf

Regards,

Henning (HoHun)

 

[NOMISYRRUC]

I'm not sure what you mean by "loft",

For what it's worth I think "loft" is a noun meaning "a room or space directly under the roof of a house or other building" and is a synonym for "attic".

However, here and on Alternatehistory.com many people use "loft" as a verb meaning "lift" or "carry".

Therefore for.

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to loft a single 20mm cannon.

Read.

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to lift a single 20mm cannon.

Or.

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to carry a single 20mm cannon.

When I looked it up Google "loft" was also a noun meaning "upward inclination given to the ball in a stroke" in the game of golf and a verb meaning "kick, hit, or throw (a ball or missile) high up" e.g. "he lofted the ball over the goalkeeper".

 

[Arjen]

On the matter of 20mm cannon and 1000hp engines: Mitsubishi A6M2 carried two 20mm cannon plus two 7.7mm machine guns with a 940hp air cooled radial.

 

[alertken]

#69,73,74 et al: beating up on Chamberlain...bad press:
“revolutionary programme of expansion (inc) off the drawing board, Shadow factories, radar...could not have (been) achieved (without Chancellor-28/5/37, then PM NC's support. I was) not obstructed by (NC)” L Swinton, 60 Years of Power, Hutchinson,1966,Pp.90/120.

 

[riggerrob]

I'm not sure what you mean by "loft",

For what it's worth I think "loft" is a noun meaning "a room or space directly under the roof of a house or other building" and is a synonym for "attic".

However, here and on Alternatehistory.com many people use "loft" as a verb meaning "lift" or "carry".

Therefore for.

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to loft a single 20mm cannon.

Read.

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to lift a single 20mm cannon.

Or.

During the late 1930s, (see Justo Miranda's book "Enemy at the Gates, Panic Fighters of World War 2), most nations were struggling to build 1,000 horsepower engines and that was barely enough to carry a single 20mm cannon.

When I looked it up Google "loft" was also a noun meaning "upward inclination given to the ball in a stroke" in the game of golf and a verb meaning "kick, hit, or throw (a ball or missile) high up" e.g. "he lofted the ball over the goalkeeper".

I meant to carry aloft ... er ... to lift into the air.

 

[JWilly]

...data from later in the war concerning the effectiveness of USAAF bomber defensive fire vs. that of escorting fighters revealed that the guns were considerably more effective when used by fighters than when fitted to bombers - about ten times better, in terms of rounds fired vs planes shot down.

Those reports are valid, but misleading. Fighter doctrine was to commence firing only at likely-hit range. Defensive doctrine was to open fire at long range to deter a closely pressed and therefore more lethal attack. If defensive hits were scored, all the better, because a damaged or injured attacker would be even more deterred. But gunners were taught that the point was to get tracers in the direction of possible attackers before they were in likely-hit range. That inherently meant a high percentage of misses...and that was fine.

 

[Tony Williams]

But gunners were taught that the point was to get tracers in the direction of possible attackers before they were in likely-hit range. That inherently meant a high percentage of misses...and that was fine.

That's true. The USAAF even adopted some .50 cal ammo for defensive guns which had an extra-bright tracer visible from the front, (from memory it was the M21, but popularly known as the "Headlight" tracer).

However, for the night bombers there was a difference of opinion within RAF crews, some of whom felt that firing tracers just revealed their position to the enemy night-fighters.

 

[HoHun]

Hi,

But gunners were taught that the point was to get tracers in the direction of possible attackers before they were in likely-hit range.

Not to say I don't see the merit of that suggestion, but is there really evidence that this ever became official doctrine? I've read quite a bit of stuff on USAAF flexible gunnery training, and off the top of my hat, I don't think this idea was ever explicitely stated. Might be my fallible memory only, of course!

Regards,

Henning (HoHun)

 

[riggerrob]

But gunners were taught that the point was to get tracers in the direction of possible attackers before they were in likely-hit range. That inherently meant a high percentage of misses...and that was fine.

That's true. The USAAF even adopted some .50 cal ammo for defensive guns which had an extra-bright tracer visible from the front, (from memory it was the M21, but popularly known as the "Headlight" tracer).

However, for the night bombers there was a difference of opinion within RAF crews, some of whom felt that firing tracers just revealed their position to the enemy night-fighters.

"Blind tracers" also exist. They are dim until "X" number of feet or meters from the muzzle. Then they burn brightly to aid in aiming. Hopefully the second or three pause is long enough to make it difficult for the enemy to locate the firer.

 

[Tony Williams]

But gunners were taught that the point was to get tracers in the direction of possible attackers before they were in likely-hit range. That inherently meant a high percentage of misses...and that was fine.

That's true. The USAAF even adopted some .50 cal ammo for defensive guns which had an extra-bright tracer visible from the front, (from memory it was the M21, but popularly known as the "Headlight" tracer).

However, for the night bombers there was a difference of opinion within RAF crews, some of whom felt that firing tracers just revealed their position to the enemy night-fighters.

"Blind tracers" also exist. They are dim until "X" number of feet or meters from the muzzle. Then they burn brightly to aid in aiming. Hopefully the second or three pause is long enough to make it difficult for the enemy to locate the firer.

German night fighters could use "Glimmspur" ammo, which was dim throughout its flight so that it was only visible from behind.

 

[HoHun]

Hi Tony,

German night fighters could use "Glimmspur" ammo, which was dim throughout its flight so that it was only visible from behind.

I just read Hajo Hermann's "Bewegtes Leben" ...he's the guy who came up with the "Wild Boar" night fighter doctrine. (Actually, the accurate translation would be "wild sow", and according to Hermann, the generals didn't like the name.)

On his first attempt to personally shoot down a bomber over Berlin with a Me 109 at night, he had made the mistake to use ammunition belts loaded with day tracers, and found they were so bright that his first burst completely ruined his night vision for a while.

After reading this, I would assume that every air force must have had night tracers of reduced brightness to avoid just this effect. "Glimmen" just means "to glow faintly" ... I'm not sure there's a direct English equivalent to this word, though etymologically, German and English seem to share a lot of words in the "light and fire" context, albeit not always with the same meaning.

(German "Spur" means "trace", by the way - but the etymolocial root is the same of the riders' spurs ... footprints versus footpressure, I guess.)

Regards,

Henning (HoHun)

 

[riggerrob]

"Wilde Sau" can also be considered an insult in modern Germany.
The German word "Sau" means the same thing as "sow" in English. Calling a woman a "sow" is an insult in both languages .... but more so in German.
When was the last time Nazis were accused of "political correctness?"
Hah!
Hah!

 

[Colonial-Marine]

Was the 13.2mm Hotchkiss the British were going to adopt the original 13.2x99mm or the later 13.2x96mm? Was this dimensional difference listed in documentation at all?

 

[Tony Williams]

Was the 13.2mm Hotchkiss the British were going to adopt the original 13.2x99mm or the later 13.2x96mm? Was this dimensional difference listed in documentation at all?

According to Labbett's British Small Arms Ammunition, it was the 13.2 x 99.

 

[HoHun]

Hi again,

But gunners were taught that the point was to get tracers in the direction of possible attackers before they were in likely-hit range.

Not to say I don't see the merit of that suggestion, but is there really evidence that this ever became official doctrine? I've read quite a bit of stuff on USAAF flexible gunnery training, and off the top of my hat, I don't think this idea was ever explicitely stated.

Coincedentally, this freshly published video shows the use of a 4:1 armour piercing/tracer mix in a few examples:

View: https://youtu.be/hGSAnQBjJDc?t=139


Unfortunately, no context with regard to theatre or date is provided, so it's difficult to draw conclusions from the observations.

Regards,

Henning (HoHun)

 

[zen]

Glimmen" just means "to glow faintly" ... I'm not sure there's a direct English equivalent to this word

Glimmer
From 'gleam'

 

[HoHun]

Hi again,

Coincedentally, this freshly published video shows the use of a 4:1 armour piercing/tracer mix in a few examples:

Well, the same guy has a new video out now titled "Why WWII Bombers Eliminated Tracers in their Ammo Belt Mixes" (Spoiler: It's because the tracers created optical illusions regarding the bullet flight path):

View: https://youtu.be/5ot_d0aG844?t=190


The first half of the video seems to be identical to the one I linked in my earlier post, but the gist of it is that after the 4:1 armour piercing/tracer mix used in early on, the USAAF switched to 2:2:1 armour piercing/incendiary/tracer later, then found the standard incendiary lacking in penetration and switched over to a new round, the armour piercing incendiary, while eliminating the tracer round entirely.

Due to the massive overclaiming by USAAF bomber gunners in WW2, and the tendency for people to report target planes as on fire when they're told those have to be on fire for a kill to be counted, I'm sceptical of the validity of the idea that when bomber gunners report a lot of burning target planes, that means the incendiary round is the most effective round in the mix.

The idea that using 100% of the most effective round will give the greatest chances for a kill certainly is valid though, but I am wondering if it's really likely that the most effective round is indeed a "compromise" round with a limited amount of incendiary material and a lighter armour-piercing core than it could have had if it hadn't allocated some space to the incendiary compound. That's conceptually not so different from the mixed belting the US considered inherently sub-optimal, and I'm not sure what data they really had to consider the API round the most effective.

The German beltings in the US document shown is based on intelligence and doesn't necessarily reflect the Luftwaffe's final thoughts on the matter, as the official "Schießfiebel" manual shows some different "optimum" beltings, if I remember correctly.

I'm also a bit sceptical against the use of POW testimonies in analysis, as POWs are likely to repeating hearsay, rationalize ad-hoc, or actively try to feed misleading information to the interviewers. I believe Galland actually admitted to massaging (or even inventing) POW reports to support his position (on jet fighters, I believe).

My overall impression is that on the Luftwaffe pilots who faced the bomber formations in combat, the sight of tracers had quite an impact - there's a popular quote like, "Dogfighting Spitfires was fun and exhilarating, but flying into the hail of tracers to attack a bomber formation made one reconsider all of one's sinful choices in life."

(Admittedly, the reported POW statement of tracers being useful because they could be used to find the poorly defended side of a formation could be turned around to show that this POW was in fact effectively deterred from attack by the tracers he saw, so maybe it's only a question of whether one likes to talk about half-full or half-empty glasses ;-.)

Regards,

Henning (HoHun)

 

[Tony Williams]

The problem with the argument concerning ammo for .50 cal bomber defensive guns is that far from abandoning tracers, the USAAF developed and adopted the M21 "Headlight" tracer specifically for the bombers. Bomber gunners reported that attacking Luftwaffe fighters tended to flinch away from tracer fire, so the M21 was designed to have a very bright tracer which was clearly visible from the front. Over 7 million of these rounds were made in 1943-44, with production continuing into 1945 to meet demand.

 

[HoHun]

Hi Tony,

The problem with the argument concerning ammo for .50 cal bomber defensive guns is that far from abandoning tracers, the USAAF developed and adopted the M21 "Headlight" tracer specifically for the bombers. Bomber gunners reported that attacking Luftwaffe fighters tended to flinch away from tracer fire, so the M21 was designed to have a very bright tracer which was clearly visible from the front. Over 7 million of these rounds were made in 1943-44, with production continuing into 1945 to meet demand.

Thanks a lot! Do you have comparative numbers for the production of AP, I and API rounds in that period so we have something to compare this figure against?

As the latter probably were also suitable for ground use, I wonder ... did the USAAF receive different ammunition grades for aviation use? I believe the RAF and probably also the Luftwaffe did, and I believe the aviation ammunition at least in the case of the RAF was selected from the lots that were in the middle of the tolerance range. I'm not quite sure if that applied to specific parameters, but I think the main concern was suitability for synchronization, so well-defined priming timing might have been the ticket.

I did in fact have the impression that the video I linked might have been overgeneralizing the issue, as I remember reading statements about tracers being eliminated from some stations but retained on others (probably the tracers were kept on the waist guns, if my rather fuzzy memory serves me). Unfortunately, I don't remember where I read this stuff, so all I can do is to promise to keep my eyes peeled and report back when I stumble upon that source again!

Which reminds me, I have Nijboer's "Gunner" lying around here, still unread.

Regards,

Henning (HoHun)

 

[Tony Williams]

Thanks a lot! Do you have comparative numbers for the production of AP, I and API rounds in that period so we have something to compare this figure against?

Sorry Henning, I don't have those to hand.

I do know that the M21 was considered unsuitable for ground use. Other tracers, among various other types, were developed for ground (inc AA) use.

Apart from the specialised M21, the following were the main types in USAAF service in late WW2 (they are still manufactured today):

- M2 AP, M33 Ball, M17 Tracer, M8 API, M20 API-T.

The M8 was considered the best all-rounder and has only been replaced relatively recently by the MK 211 SAPHEI (Raufoss Multipurpose type). The M20 was developed for those who wanted additional tracer effects (not all pilots did, as they warned the enemy that they were under fire).

 

[Colonial-Marine]

It seems the .50 caliber API rounds were pretty well respected by pilots. One of the reasons I've seen for the poorer performance of the .50 cal over Korea was that at the altitudes the F-86s were flying at the incendiary compound didn't burn very well but that wasn't the case in WWII.

 

[HoHun]

Hi again,

I did in fact have the impression that the video I linked might have been overgeneralizing the issue, as I remember reading statements about tracers being eliminated from some stations but retained on others (probably the tracers were kept on the waist guns, if my rather fuzzy memory serves me). Unfortunately, I don't remember where I read this stuff, so all I can do is to promise to keep my eyes peeled and report back when I stumble upon that source again!

Well, that was quicker than I expected, though I was right to cast doubt on my memory as I had the tracer/non-tracer positions backwards ... quoting "The Mighty Eigth' War Manual" by Roger Freeman (p. 230):

"Tracer was soon found to be of questionable value as it caused gunners to disregard their sights when using it. Tracer also offered a serious optical illusion, particularly with beam shooting. On the other hand, it had advantages in alerting other gunners in a formation and was also of value as a deterrent to attacking enemy pilots. It became general practice to only use tracer rounds in front and rear turrets where optical illusion was negligible. A brighter tracer round known as 'headlight' was introduced during 1944 and used in these positions in a one tracer to four AP incendiary rounds ratio supply - at this time the combined armour piercing incendiary had replaced the separate AP and incendiary rounds in general usage."

Regards,

Henning (HoHun)

 

[HoHun]

Hi,

It seems the .50 caliber API rounds were pretty well respected by pilots. One of the reasons I've seen for the poorer performance of the .50 cal over Korea was that at the altitudes the F-86s were flying at the incendiary compound didn't burn very well but that wasn't the case in WWII.

I presume that's the US pilots' perspective, and comparing it to the other rounds in the same calibre The Korean War experience did in fact convince the USAAF that cannons were the way forward ... the US Navy had already advocated cannon in WW2.

While that's probably a bit of a tangent, the German pilots' perspective generally was that the Luftwaffe fighters had a decided edge in guns and ammunition. Here's an example from Priller's "JG 26" (p. 357):

"It should be mentioned that the German ammunition for the entire duration of the war was far superior to the ammunition of the enemy."

To be fair, they also appreciated the effect of incendiary rounds:

"Special emphasis needs to be put on the last version of the incendiary round, from about 1944. The old incendiary rounds didn't do any damage when firing at a four-engined bombers because the incendiary charge had already burned out by the time the projectile reached the main tank in the forward part of the wing. The new incendiary round on each subsequent impact generated a new jet of fire. It could pierce about 5 to 7 skins, spars, tanks and such, before the incendiary charge was fully consumed."

(I am not sure whether that was a 20 mm or a 13 mm round ... there is a 2 cm Br. Gr. 44 o. Zerleg. - '2 cm incendiary shell without self-destruction, 1944' -, but from the cutaway, I am not sure it has this multiple-squirt capability since it has an explosive charge towards to front end that. Maybe Tony knows more? I am sure I saw a detailed description of the projectile Priller describes in a Waffen Revue issue a couple of years back.)

Regards,

Henning (HoHun)

 

[Tony Williams]

Special emphasis needs to be put on the last version of the incendiary round, from about 1944. The old incendiary rounds didn't do any damage when firing at a four-engined bombers because the incendiary charge had already burned out by the time the projectile reached the main tank in the forward part of the wing. The new incendiary round on each subsequent impact generated a new jet of fire. It could pierce about 5 to 7 skins, spars, tanks and such, before the incendiary charge was fully consumed."

I've never heard of that. Sounds amazingly complicated.

The Luftwaffe did use a hydrostatic fuze ( AZ 9501 Flussigkeitszunder) which was designed to function when the round entered a fuel tank, but that's as close as I can get!

 

[HoHun]

Hi again,

Well, that was quicker than I expected, though I was right to cast doubt on my memory as I had the tracer/non-tracer positions backwards ... quoting "The Mighty Eigth' War Manual" by Roger Freeman (p. 230):

"Tracer was soon found to be of questionable value as it caused gunners to disregard their sights when using it. Tracer also offered a serious optical illusion, particularly with beam shooting. On the other hand, it had advantages in alerting other gunners in a formation and was also of value as a deterrent to attacking enemy pilots. It became general practice to only use tracer rounds in front and rear turrets where optical illusion was negligible. A brighter tracer round known as 'headlight' was introduced during 1944 and used in these positions in a one tracer to four AP incendiary rounds ratio supply - at this time the combined armour piercing incendiary had replaced the separate AP and incendiary rounds in general usage."

Here's a manual "Flexible Gunnery Training in the AAF", which covers the limitations of tracers starting on p. 126 (by PDF count ... it's p. 54 by scanned page numbers):

https://www.afhra.af.mil/Portals/16/documents/Studies/1-50/AFD-090602-068.pdf

Regards,

Henning (HoHun)