WWII aircraft armament machine guns and cannon

[davidsog]

This leads to the conclusion that there had to be something different about the fuel used. Isn't it possible that the fuel sold to Britain was different in some way from what was used in the US? Octane rating isn't the only thing that can be different in different grades of gasoline.

Very true. One of the reasons why Aircraft engines must use only the fuel that is listed on the approved Specification Sheet.

You cannot run just any fuel and Octane rating is actually subjective not to mention varies significantly with the method used for testing it.

We went thru this converting the DB series and BMW radial to use 100/130 octane (100LL). The German engines will use natural petroleum fuels but you will lose some power and they tend to run rougher at altitude on the Natural Petroleum fuels. The higher you go, the worse it gets with the largest change being the first 8000 feet. The Germans had better octane rated fuels than the allies and had them much earlier. At least that is what Allied Testing of German fuels shows.

That being said, comparing Octane rating between the two is not a good measure of the power production, it is really apples and oranges.

[davidsog]

Here is the P38J, H, and F-5B Fuel Specifications from the POH:

[4V50 Gary]

Keep in mind that the Germans fought at a severe disadvantage (happily so).

They had a longer flight and over water and if a Brit pilot bailed out, if he was alive he was recovered. The Germans lost all pilots who bailed out and probably within 10 miles of the UK coast (their rescue service operated somewhere in those margins).

But they also had a flight back over the channel, so anything that went down as crews and aircraft very possibly gone.

Both sides had lifesaving buoys that had offered shelter and food. The RAF also operated small boats tasked with recovering airmen. Both sides had seaplanes that could land and rescue a downed pilot. Churchill ordered the RAF to shoot down German marked Red Cross aircraft.

To make up the power difference it was run at higher boost levels which required the highest octane available. US fuels were probably some of the best at the time.To make up the power difference it was run at higher boost levels which required the highest octane available. US fuels were probably some of the best at the time.

Concur that the US aviation fuel was the best. Highest octane and it gave us an edge.

[davidsog]

Both sides had lifesaving buoys that had offered shelter and food. The RAF also operated small boats tasked with recovering airmen. Both sides had seaplanes that could land and rescue a downed pilot. Churchill ordered the RAF to shoot down German marked Red Cross aircraft.

Yep, and the Luftwaffe had a very good SAR capability. They even rescued RAF pilots. In fact, both the Royal Navy and the Luftwaffe serviced/restocked The German Lifebuoy shelters.

Between February and August of 1941, of the over 1200 air crews from both sides that went down in the North Sea and English Channel, 444 of them were saved by the Seenotdienst. Of those 444, 78 were RAF crews. With painful awareness that British efforts were severely lacking in air-sea rescue during the Battle of Britain, in 1941 the RAF Coastal Command set about improving its air rescue capability and would use the Seenotdienst as a model. With the expansion of the US Army Air Forces in Britain, the RAF Coastal Command in turn assisted the United States in developing its air sea rescue capabilities.

The emphasis on Air Sea Rescue can be seen in the fact Luftwaffe pilots got a life raft, a survival kit with rifle, and a whole host of signaling devices including sea dye.

In 1940, RAF pilots got a life vest and...
Survival aids - flying rations / escape box / currency pouch / escape maps

[davidsog]

Concur that the US aviation fuel was the best. Highest octane and it gave us an edge.

Cheapest and easiest to manufacture, yes.

As for giving an "edge" in motor performance..NO. Direct fuel injection trumps Throttle Body Injection all day long. It gets more power from the same fuel under any circumstances. The Allies did not field a single DI engine during the war.

The Hydrogenation process meant Germany was fielding C3 fuel that had an equivalent Octane Rating of 100-110/140 grade in 1941. It wasn't until the last year of the war the Allies could get such a high octane number to run and they never got such a high octane number to run reliably.

92% the Aviation fuel produced by Germany during the entire war was hydrogenated.



The Germans had the equivalent to British 100/150 grade or US 115/145 grade (post war fuel) fielded by 1943.

[Pumpkin]

GDI should have allowed for lower octane because of the in cylinder charge air cooling.

What affect did GDI have on engine fire after combat damage?
Those systems typically require a lot higher fuel pressure than a carbureted setup.

Any thoughts on how the inverted vee layout helped or hindered the weapons?
I would think gun heaters might not be so important?
Spark plug changes should have been easier along with valve lash adjustments.

[4V50 Gary]

Example of life buoy

https://youtu.be/a90_QdrKo1Q?si=UhRoKqCzIJ5FQLGe

[44 AMP]

Not my area of expertise, but I am thinking there must have been a difference between the gasoline rating systems used by Germany and the Allies.

German piston engine fighter aircraft have a yellow triangle marking with a number in it, and all (english language) reference material I've ever seen identifies the marking as the Fuel octane rating for the aircraft.

The number is 87, which is the same number I see on the gas pump for "regular" gas when I fill up my car.

Did the 109s, 110s, and 190s run on what we know as regular? OR was their rating system different from ours and the number 87 for Luftwaffe avgas just a coincidence?

[Pumpkin]

Man add a couple of windows to that buoy and it could make a hunting cabin!

[Pumpkin]

Originally Posted by 44 AMP

Not my area of expertise, but I am thinking there must have been a difference between the gasoline rating systems used by Germany and the Allies.

German piston engine fighter aircraft have a yellow triangle marking with a number in it, and all (english language) reference material I've ever seen identifies the marking as the Fuel octane rating for the aircraft.

The number is 87, which is the same number I see on the gas pump for "regular" gas when I fill up my car.

Did the 109s, 110s, and 190s run on what we know as regular? OR was their rating system different from ours and the number 87 for Luftwaffe avgas just a coincidence?

Well the Spitfire Mk1 made almost the same hp with a smaller engine than the Bf 109. The Merlin was higher stressed to accomplish this.

[davidsog]

Any thoughts on how the inverted vee layout helped or hindered the weapons?
I would think gun heaters might not be so important?

The inverted V offered some advantages. Mainly drag reduction, Pilot visibility, and being able to mount centerline weapons.

It also restricted you to dry sump engine designs and left the engine susceptible to hydrolock just like any radial engine.

Since radials were pretty common, it wasn't a big deal...just more work for the ground crew because they have to pull the prop thru several times with the ignition off and count blades before you can make the ignition hot to start it.

[2damnold4this]

I would assume it is a Browning .50 caliber as in 1939, the RAF officially retired the Vickers .50 cal due to its unreliability.

The Browning .50 cal was adopted instead also in 1939. The report is almost 4 years after that decision so it would make little sense to test an obsolete and retired weapon system.

Kynoch was still making ammunition for the Vickers 0.50 in 1945 for naval antiaircraft use.

They call the bullet AP&B Mkii in your chart. That sounds like a Vickers mark II ball round. It doesn't start a fire in the gas tank tested but neither does the 20mm AP round on the chart.

If we had the whole paper, we'd know the date of the paper and what exact guns and bullets were tested.

[davidsog]

Well the Spitfire Mk1 made almost the same hp with a smaller engine than the Bf 109. The Merlin was higher stressed to accomplish this.

It's very hard to make a blanket statement. The Merlin has some 20 plus variants, the DB601 almost as many, and DB605 as well.

[davidsog]

Kynoch was still making ammunition for the Vickers 0.50 in 1945 for naval antiaircraft use.

The Royal Air Force is not the Royal Navy...

AP&B Mkii

They call a variant of the Spitfire MkII...
A version of the Sten Gun is the MkII...

It's the MOD..everything gets a MkII.

[davidsog]

If we had the whole paper, we'd know the date of the paper and what exact guns and bullets were tested.

It just says .50 cal B. Mk II Incendiary and .50 Cal Armor Piercing. The "B" is for "Browning" as noted in the MOD ammunition nomenclature. The report does not list a Mk1z or Mk II for the AP rounds which also adds credence to the weapon tested being the M2 Browning adopted in 1939 by the RAF. The original Browning .50 Cal AP rounds in the MOD inventory were just Remington AP rounds that simply said ".50 cal Armor Piercing". There was MOD inventory designation on the packages.

The .50 cal Vickers did not have Incendiary MKII ammunition in MOD service anywhere. The Vickers used Incendiary Mk 1 and Mk 1z

It only used Mk I and Mk Iz until the weapon was phased out of all MOD service in 1948.

https://sites.google.com/site/britmi...rmour-piercing

The M2 Browning as adopted by the RAF in 1939 used the MOD .50 cal B Mk II Incendiary ammunition. It also used a "B" for Browning in its designation:

https://sites.google.com/site/britmi...ing-incendiary

The Absence of a Vickers .50 cal MK II round in the MOD inventory and the fact the RAF discarded the Vickers .50 cal in 1939 seem to point to the round being an M2 Browning .50 caliber round.

It is confusing and it would be nice if the RAE had been more specific taking pity on us readers 80 years in the future. So far, it seems to be a "B" for Browning and not a Vickers.

[44 AMP]

Am not saying this is the case here, but I have read a number of British tests and evaluations of aircraft and armor, and in general its rare to find one that doesn't rate British designs and equipment more favorably than everyone else's.

Tests are tests, but tests can be flawed, intentionally or unintentionally, just watch a few episodes of Myth Busters to see that in action.

[Pumpkin]

As I said before, how the 50BMG and the 303 British are mentioned together makes my head hurt.
I understand neither are a cannon round but the similarities end there.

[2damnold4this]

It just says .50 cal B. Mk II Incendiary and .50 Cal Armor Piercing.

Could you flag that for me in the fragment of the report you posted? I don't see the word incendiary connected with the bullet. We do see it possibly connected to 20mm ammo: "20mm H.E./I" and "20mm S.A.P./I." but I don't see it connected to the mystery 0.50 ammo in your pic. I think it's safe to say that 0.303" B. Mk VII mentioned in your post is Mk VII ball and not an incendiary round. Why would 0.50 B. MkII be something other than this: https://sites.google.com/site/britmi...h-vickers-ball

If we had the whole paper, we wouldn't have to guess.


Edit: I was wrong about the 0.303 and 0.50 rounds in the report being ball. The "B" apparently stands for "Buckingham" and is what the Brits used to designate an incendiary round.

[2damnold4this]

The "B" is for "Browning" as noted in the MOD ammunition nomenclature.

From your additional links it looks like you while you are mistaken about the "b" meaning Browning but you are right about the bullets being incendiary and you are almost certainly right about the bullets being tested being British made bullets for the Browning ANM2.

From your links we have this: "Cartridge S.A. Incendiary .50 inch Browning B Mark Iz" and this: "Cartridge S.A. Incendiary Buckingham .303 inch (VII.B) Mark III" and "Cartridge S.A. Incendiary Buckingham .303 inch NCZ (VII.B) Mark III.z" were approved to design IDW 4548 (cartridge) and IDW 4549 (bullet) in July 1917 and not shown in Lists of Changes. The title was changed in 1925 to "Cartridge S.A. Incendiary .303 inch (VII.B) Mark III"

The B seems to have been for Buckingham.

The bullet and cartridge in question is almost certainly this from your link:"Cartridge S.A. Incendiary .50 inch Browning B Mark IIz" was approved to design DD/L/11847 in late 1941.

The case was a British manufactured .50 inch Browning fitted with a Berdan primer with a blue primer annulus. The headstamp was typically "SR 1942 .50", but some rounds were loaded in Britain in Canadian cases headstamped "DI 42".

The bullet was flat based with a gilding metal envelope containing a steel sleeve within a thin lead outer sleeve. The incendiary composition was contained within the steel sleeve and the tip of the bullet in a similar manner to the .303 inch B Mark VII incendiary.. The tip of the bullet in early production was pierced with a small solder filled hole, but this was omitted in later production from May 1943. Bullet weight was 710 grains and the tip was coloured blue.

The incendiary composition was 36 grains of SR 365 with 2 grains of QF composition in the nose.

So yes, it seems that the bullet being tested was almost certainly a British made incendiary version of the .50 BMG made to be fired in an American supplied ANM2.

[davidsog]

The B seems to have been for Buckingham.

That could be it.

The Box from MOD says:



The Report says ".5" B. Mk II Incendiary"

.5 Inch Browning Mk II....

You certain it means "Buckingham" and what is the source?

So yes, it seems that the bullet being tested was almost certainly a British made incendiary version of the .50 BMG made to be fired in an American supplied ANM2.

Given that the RAF dumped the Vickers .50 cal in 1939...
It makes little sense to test a weapon you are not using.

I found the rest of the report but will have to scan it to post. I was wrong about the target being an actual FW190. It was a mock up made from referencing an actual FW190. They couldn't get the stringers (support structure), controls, or retractable tailwheel so the test results are probably a little optimistic penetration wise but the general conclusion holds as the test was about the ability to start a fire hitting the tanks or killing the pilot.

The target was basically the fuel tanks and the pilot armor in an aluminum tube.

[Pumpkin]

Originally Posted by 44 AMP

Not my area of expertise, but I am thinking there must have been a difference between the gasoline rating systems used by Germany and the Allies.

German piston engine fighter aircraft have a yellow triangle marking with a number in it, and all (english language) reference material I've ever seen identifies the marking as the Fuel octane rating for the aircraft.

The number is 87, which is the same number I see on the gas pump for "regular" gas when I fill up my car.

Did the 109s, 110s, and 190s run on what we know as regular? OR was their rating system different from ours and the number 87 for Luftwaffe avgas just a coincidence?

Here is a great write up in an easy to understand format.
Yes, the Germans had a octane/performance advantage at the start of the conflict but were quickly surpassed by US Avgas numbers.

https://militaryhistorynow.com/2024/...google_vignett

[2damnold4this]

You certain it means "Buckingham" and what is the source?

Your British Military site has this on 0.303 incendiary rounds: "Cartridge S.A. Incendiary Buckingham .303 inch (VII.B)" was approved to designs RL.24642 and IDW 4514 in July 1916 but was not shown in Lists of Changes. The title was later changed to "Cartridge S.A. Incendiary Buckingham .303 inch (VII.B) Mark II" and the word "Buckingham" was dropped from the title in 1923 and in 1927 the title was again changed to "Cartridge S.A. Incendiary .303 inch B Mark II".

The ammo tested in your paper is almost certainly this: "Cartridge S.A. Incendiary .50 inch Browning B Mark IIz" was approved to design DD/L/11847 in late 1941.
Which is a British made incendiary bullet based on the 0.303 B Mark VII. From your link:
The incendiary composition was contained within the steel sleeve and the tip of the bullet in a similar manner to the .303 inch B Mark VII incendiary..
It seems that the "B" label is for the design that Buckingham made for putting an incendiary charge in a bullet, whether it was for a 0.303 or a 0.50. From your link we see that the British didn't want to use American made incendiary rounds and made their own based on their indigenous 0.303 designs that used Buckingham's method: Although adopted for service British authorities were unhappy with the American Incendiary M1, considering it not to be bore safe due to the incendiary composition being pinched between the steel sleeve and the envelope. The development of a British incendiary was considered a high priority.


.303 incendiary link: https://sites.google.com/site/britmi...nch-incendiary

I appreciate the links and information you have provided.

[davidsog]

I appreciate the links and information you have provided.

No problem. Discussion is welcome.

My only issue with the "Buckingham" is the MOD's emphasis on separating British weapons from the American adaptation, specifically "Browning" in the adaptation of the .5 inch M2.

We are having this discussion trying to find out which ammo is which. Imagine the confusion at the unit level. That is why all the MOD cartridge boxes are very specific. It is unfortunate for us that both "Buckingham" and "Browning" start with a "B".

I think that there is a possibility the "B" does not necessarily means the same thing in the MOD inventory just like thousands of "Mk II's".

In the case of the .303, it makes sense to be "Buckingham" as the cartridge is the same .303 British not matter if its fired from a No. 1 MkIV or .303 Browning. It simply needs to be linked.

In the case of .50 inch Vickers and .5 inch Browning...these are two different cartridges that you would not want to get mixed up.

[davidsog]

Here is a great write up in an easy to understand format.
Yes, the Germans had a octane/performance advantage at the start of the conflict but were quickly surpassed by US Avgas numbers.

Good article but it has some flaws. P-38's for example never used 150 grade in Combat anywhere. P-47's were approved but then disapproved with the conflict ending before the issues could be resolved.

The United State Petroleum board nixed the production of the higher octane experimental fuels except a small output for experimentation, development, and later production. 100/130 octane was the staple for the USAAF.

A Special Project was enacted by the 8th AF FG and that is 44-1 or British 150 grade. Special Project is not adaptation, it is just a Special Project to gather experience and information. Only the P51's used 44-1 in combat and at a much lower MAP rating than the British used in the ADGB. IIRC, 67" was what the 8th USAAF P-51's used instead of the 72" used by the ADGB. In talking to 8th AF veterans who used 44-1 and flew missions, it was not as popular with all the pilots as it was with the command. Even at the reduced MAP, it required special procedures to keep from lead fouling plugs in cruise flight. It does you no good to have a powerful V12 if it turns into a V8 by the time you reach the fight. The issue became so bad, 100/130 Octane became a pirated item in the squadrons with units requesting to be returned it permanently. It was worked out in the last few months of the war between additional additives and the adoption of those special procedures. Its adoption was withdraw and reinstated several time ebbing and flowing. It wasn't WarThunder and the idea it was some fuel was a wunderwaffe that won the war is just not true.

British 150 grade also had issues with its ability to be run reliably. It was bad enough, the Technical Services (Mechanics) did not recommend its use. It was finally pushed upon them but was only used in the ADGB chasing Buzzbombs. Those aircraft did not leave the shores of England.

The 2nd TAF was approved to use 100/150 grade in Jan 1945. They had the same issues with the fuel as everybody else but simply accepted the increased maintenance and pilot casualties it incurs.

Post War, everyone dropped Aviation fuel in excess of 145 Octane. That seemed to be the sweet spot giving maximum power with reasonable chance of retaining it and having an airplane you could fly again.

[davidsog]

Here is a snippet from the 8th USAAF Fighter Commands After Action Review. I came across it and thought it was relevant given the earlier discussion on firing limits of the M2 Aerial Machinegun mounted in US Fighters.


Here is what they say about the shooting analysis: