WWII aircraft armament machine guns and cannon

[RC20]

I have often wondered in the Battle of Britain if the UK had at least gone with 50 cal what the increased damaged would have been in German losses.

Maybe too early for that to have happened, the 50 Cal was still proving itself.

Also have pondered dropping a couple of the 50s off a P-47 and what that would have done for combat agility? Or trade off for more ammo.

One aspect not mentioned as been the climb rate of the P-47 once it got the right prop.

[105kw]

If the pilot wanted to save weight in a P-47, a simple solution was to drop ammo load from 425rpg, to 267rpg.
Another high performance P-47, was the P-47M. It used the P-47N engine, it a P-47D lightened airframe. They removed the wing hard points, and got 475mph at 30,000ft.
About 150 were built, only served in the 56th FG,in the 8th AF.
They reached service in late 1944.

[Pumpkin]

I thought it was actually clocked at just over 500.
Urban legend maybe…

[105kw]

Not urban legend, the P-47J.
Did 504mph, in a test run.

[44 AMP]

I have often wondered in the Battle of Britain if the UK had at least gone with 50 cal what the increased damaged would have been in German losses.

Maybe too early for that to have happened, the 50 Cal was still proving itself.

I think that the German losses had the UK armed its fighters with the .50BMG would have increased slightly, but I doubt the RAF's hit percentage would have gone up any with the tactics they used at the time. The "Dowding Spread" and the practice of the entire flight firing when the leader did were eventually recognized as very flawed, but it wasn't until individual squadrons lead by their FLt leaders, and commanders dropped those tactics, on their own without high command approval that hit percentages went up.

Also, the .50 BMG was well proven in the summer of 1940. The US was putting a .50 in its fighters since the early 30s and all of our primary inservice fighters from the later 30s on carried at least a pair of .50s as cowl guns (p-39 & P-40) and the Navy's F4F Wildcats had four, a pair in each wing, in 1940.

I'd say that having been in Army ground use since 1921 and in aircraft use since 1933 (possibly earlier) the .50BMG was well proven, and when we went into actual combat in Dec 41, and from then on, the results vindicated the concept, and how!

[RC20]

For clarification, my intent was to convey that the 50 cal had not been used in combat and specifically proven in aerial combat.

For all the testing, real use and even more so combat tells you if its a good one, has some issue to work out or a problem.

While the US had experience with the 50 cal, someone else looking at it could well question it.

I think it was the right gun for the AAC and Navy/Marines for WWII. 20mm was attempted but they had problems with the ammo that amazingly did not get sorted out till 1944.

UK had issues with their initial installations. A good gun and caliber, but justified slower cross over until it was proven solid.

US faced fighters and light bombers for the most part so the 50 cal was a good caliber for that. The longer firing time vs 20mm was an advantage in my view as well.

Something to keep in mind, the RAF fighters would get broken into segments after initial contact so there was a lot of aerial combat that was not line astern nor the firing doctrine.

[Pumpkin]

Not to sound ignorant, but I am, what was, Line astern and the Firing Doctrine?
Also, have to agree with the 50 vs 20mm choice by the US. Had we been facing squadrons of He177s and Ju290s flown from Central America
(or somewhere else close) maybe we would have added some cannons to our interceptors.

[davidsog]

It turns out a P-47 was the first long distance fighter over Berlin (by a day, I think a P-38 was next).

The AAC by not allowing drop tanks made sure the P-47 could not do mid and long range escorting. Interesting the highest scoring guy in Europe flew P-47s.

There were some good reasons why the P-51 was favored for long range escort over the P47.

Loaded at max economy, the Merlin engine used 15-20 gallons per hour less than the R-2800 in fuel. Hundreds and sometime thousands of airplanes flying 6-8 hour missions...that is a significant fuel savings. Aviation fuel was in short supply for everybody. The Fuels conference in 1943 absolutely shut down any development of higher octane fuels over 100/130 grade except on a very limited amount for research and development due to the fact refinery capability was at capacity.

Also consider an R-2800 uses 33 quarts of oil per hour at maximum continuous and 13 quarts per hour at minimum specific fuel (max range). The P47 holds 28 gallons of oil.

A P-51 holds 20 gallons of oil. The Merlin consumes 14 quarts at max continuous power and only 6 quarts per hour at minimum specific.

That is a lot of fuel and oil savings using a P51 over a P47 for the same mission.

[44 AMP]

Balance the fact that the R2800 is a gas and oil hog against the fact that the big radial would often take damage that would put an inline liquid cooled fighter down, and get its pilot home. Always? no. But often, yes.

Gas and oil matter, but in the big picture, they are always cheaper than blood.

Way cheaper.

[Pumpkin]

Too bad those in charge don’t see things the same as the rest of us.

[44 AMP]

Too bad those in charge don’t see things the same as the rest of us.

Their world and our world are not the same world, but there is considerable overlap when the stars line up.

And, in fact, those in charge often don't see things the same as other people in charge, history is FULL of examples.

The further up the chain one goes, the larger the potential impact of even small decisions have.

A single soldier, sailor, airman or marine in the lower ranks doing their own thing rarely turns the tide of a battle though it has happened. An officer commanding a unit, can, and the higher the officer the greater the change that can result.

what was, Line astern and the Firing Doctrine?

Line astern with aircraft is the same as line astern with ships. Each unit follows behind the leader in a single line like beads on a string. However, air combat showed that the last guy in line was vulnerable to being bounced. The "Tail end Charlie" had no one covering him.

The "Firing Doctrine" used by the RAF (until discarded) was the aerial version of volley fire in ground combat, basically everyone lined up and firing at the same time the commander did (or ordered). The idea was to "fill the area with bullets". Works ok when the enemy is lined up facing you, less so, when they aren't.

[davidsog]

Gas and oil matter, but in the big picture, they are always cheaper than blood.

And having an airplane in the sky is much better than not having an airplane in the sky.

There was a shortage of 100/130 grade fuel. In fact, Allied Aviation fuel production never reached the levels required. That is the big reason why you see the P-47's removed from England, regulated to ground attack, and moved closer to the Fronts lines in Italy.

The United States abandoned all high octane fuel research except the 115/145 octane fuel that became the post war standard. It never made it into combat.

That was due to refinery capability. We just needed every refinery cranking out fuel at capacity with none to spare. Even then, we had significant shortages and never reached the stockpiles required.

Using the P-47 for long range escort would have added considerable stress to an already stressed supply chain.

From the Fuels Conference of 1944:

Engine Performance was a consideration but was not the only one....

[105kw]

Except, P-47s were not removed from Northern Europe.
The 8th AF, converted its last P-47 unit, the 78th FG, to P-51s in Dec. 1944.
At its peak, the 9th AF had 14, P-47 FGs on strength, the 8th had one, the 56th.
Add in 14, P-51 groups in the 8th AF, and 3 in the 9th, you get a lot of USAAF fighters in England, and France.
The only P-38 fighter unit left in Northern Europe at VE day, was the 474th in the 9th AF.

[Pumpkin]

44 AMP,
Well when those Brits decided to let fly with all those .303’s it must have been impressive, when it worked
Sounds like left over Revolutionary War tactics.
Thanks, I never knew this!

[44 AMP]

Put enough bullets in the air, you're bound to hit something but most might only hit the ground.

Add to this, the "Dowding Spread" which was SOP, where the fighter's guns were regulated to hit in a 10 ft circle at range (300yds, I believe). Compare this with other nations policies of regulating the guns into a 2 ft or 3ft area at that range, or allowing individual pilots to decide what regulation they wanted their guns set to.

[Pumpkin]

I just got a new to me book on the Tiger vs the Firefly.
The author writes that the Firefly gun was second only to the King Tiger, leaving third place to the Tigers 88.
Is this a error or true?
He also has an account of a Firefly sergeant Douglas Gordon with his crew destroying 3 Tigers at 800 meters, one of them being the Tiger of the highly decorated Michael Whittman.
Could this have been a case of mistaken identity with the Tigers thinking these were standard Sherman’s or maybe arrogance on the Germans part?

[RC20]

I would call it Hyperbole though the 17 lb (Firefly gun) was a very capable gun.

Frankly I would put the German 75 mm version in the Panther as the top gun. It could basically penetrate anything. The 88mm was a waste in my view. It did get you a bigger HE round.

I would put the long 75 mm on the Pzkw IV as number 2. But also situation specific, US 75 mm was quite a bit better HE round than the 76mm (had to do with wanting the same trajectory so the removed powder from it which was stupid). Walk it in. Close often is good enough and if not first, 2nd round gets them.

Keep in mind it also was the Ammunition, with what they called HVAP the Sherman 76mm could penetrate anything but a Tiger II front.

Generally you could penetrate armor from the side and I believe that is what got Witman.

[RC20]

Line astern with aircraft is the same as line astern with ships. Each unit follows behind the leader in a single line like beads on a string. However, air combat showed that the last guy in line was vulnerable to being bounced. The "Tail end Charlie" had no one covering him.

Its more than that. Its time consuming to let one aircraft lead while the others Q up to follow and then its a single point of attack that all defensive guns can focus on a single aircraft.

Like a lot of Doctrine, just plain dumb. Swarm the lot.

[RC20]

P-47s were in Europe before the Merlin Mustangs and they could and did make Berlin regardless of fuel use (I don't have those numbers but they sound wrong). They can and did do long range escort once the brass was forced to accept the doctrine of un-escorted was wrong.

Europe was peanuts compared to the Pacific as far as range went.

[44 AMP]

I just got a new to me book on the Tiger vs the Firefly.
The author writes that the Firefly gun was second only to the King Tiger, leaving third place to the Tigers 88.
Is this a error or true?

It's an opinion.
(side bet the author is English )

This is not to say the 17pounder wasn't a good gun, it was, and was on a par with the German 75mm L/70 used in the Panther. BOTH guns fired a 17lb AP round at just over 3,000fps. Do note that the German gun went into combat in July 43 and the British one almost a year later.

The King Tiger gun was an 88mm L/71 which fired a 22lb AP at about 3,600fps. It was used by the Ferdinand/Elefant, the Nashorn (in 43) and the king Tiger and Jagdpanther from mid 44 on.

He also has an account of a Firefly sergeant Douglas Gordon with his crew destroying 3 Tigers at 800 meters, one of them being the Tiger of the highly decorated Michael Whittman.

Does the account by any chance mention WHERE on the vehicle the Tigers were hit?? Tigers had 100mm on the front sides and rear were 80mm, as thick as the thickest armor on a Sherman. The 17 pounder had a good chance of penetrating the front of a Tiger at 800m and would certainly get through the hull or turret sides at that range.

I have seen several accounts of the destruction of Wittman's Tiger. All different. Killed by a Firefly, surrounded and killed by (up to) half a dozen Shermans, and destroyed by air attack from fighter bombers. I can't say for certain, but my opinion favors air attack as the most likely.

[Pumpkin]

I have to agree with your side bet. I’m pretty sure he’s a bloke
His account, Stephen A Hart, is of a broadside 800m hit resulting in the ammo storage going off after a couple of seconds. Apparently the turret was found some distance from the impact.
The version of his demise including aircraft mentioned Tempests with rockets which also sounds believable.
Various accounts show anywhere from 3 to 5 Tigers.

[davidsog]

Except, P-47s were not removed from Northern Europe.

And nobody made any claim they were....

davidsog says:

That is the big reason why you see the P-47's removed from England, regulated to ground attack, and moved closer to the Fronts lines in Italy.

P-47's were relieved of the long range escort missions of the 8th USAAF whose primary mission was the strategic bombing of Europe.

The 8th AF, converted its last P-47 unit, the 78th FG, to P-51s in Dec. 1944.

Correct. The P47 was relieved of its long range bomber escort mission and moved to the 9th USAAF. The 9th USAAF had a different mission from the 8th USAAF. The 9th USAAF was THE Tactical Air Force for the USAAF.

That move saved considerable fuel and oil use as well as focused the more rugged aircraft onto the more dangerous mission. It's kind of a win-win decision.

[davidsog]

P-47s were in Europe before the Merlin Mustangs and they could and did make Berlin regardless of fuel use (I don't have those numbers but they sound wrong). They can and did do long range escort once the brass was forced to accept the doctrine of un-escorted was wrong.

Yes. If you read the correspondence and debate going on inside the USAAF, the biggest concern was a shortage of both drop tanks and fuel consumption.

Combine that with fact the Mustang units of the 9th AAF were much more vulnerable to ground fire than their P47 brethren, it just made sense to drop the P47 from the Long Range Fighter Escort Mission of the 8th USAAF and focus them on Tactical Air of the 9th USAAF. The 8th USAAF got more Mustangs and the 9th got more P47's.

[44 AMP]

That move saved considerable fuel and oil use as well as focused the more rugged aircraft onto the more dangerous mission. It's kind of a win-win decision.

There's no question the P-47 was a superior ground attack aircraft, but I fail to see where there is a fuel/oil saving, outside of the bean counter managing the fuel stocks for the 8th AAF.

The P-47s and 38s were still THERE, still operating out of England, still using fuel and oil at the same rates. Changing their administrative overhead doesn't change the aircraft engines. And, the 8th AAF didn't fly to Berlin and beyond daily. Ground attack and escorting medium bombers I think probably racked up more miles flown per aircraft. I'm sure there's a study some where with a graph showing who flew what, were, when, and how often....

[davidsog]

I fail to see where there is a fuel/oil saving

Maybe if you read the Specific fuel Consumption rates on the aircraft you would see it.....

55 GPH at SL for P47 vs 28GPH at SL for P51. The P47 consumes roughly 70-80% more fuel under the same conditions on average.

The same trend follows for oil.