20mm cannon, best, worst, specs, comparison to LMG, HMG etc. (1 Viewer)

[Glider]

Thats another way of saying what I have been. It worked therefore not a major concern to switch so they did not.

I had to like this posting. Anything that makes me laugh must be a like.

 

[Glider]

While your posting, would you like to support this statement of yours with some evidence?

You apparently do not understand damage physics. There is simply is no way to predict or compare prediction for mechanical vs chemical damage, they use different physics.

A .50 cal bullet going through Al skin leaves .50 cal hole, the explosive creates over pressure. The overpressure if constrained (as in a time delay and is inside the plane) expand until a opening is found a one is created at the weakest points.
OTOH a 20mm impact and detonation on the surface of hard object (engine) only has overpressure (generally at point of impact) to damage the hard object. Cast iron and steel can take alot of overpressure. But SAPI .50 round breaks the brittle engine metal. Cracks propagate especially under load. They also can a did pierce the armor plate and other hard objects. The 20mm did not generally go through Armor plate. (Read Bobs book he took several 20mm hits in the armor in his P-47).

 

[zjtins]

For the USAAF I agree!! But the USN wanted something more

But wanting in the time of war has to be prioritized with resources other needs and expected results etc.

I will expand on my original statement. The .50 was sufficient for WWII. That is not saying the .50 setup was better but good enough. Good enough implies the powers that be at the time viewed a change would cost more than the benefit.

Yes The US navy wanted a near one shot kill. I base that on the 37 MM and other testing they continue for over 20 years then went to missiles and ordered the F-4 without a gun and later added back. (big step but I think its germane).

Meanwhile every major player in WWI had used .50s as some or all of their armament on their planes. The Russians used in tandem for most (in think do not have numbers) of the was a 20mm and .50cal (equivalent). The Germans added two .50 on both there major fighters in place of .30 cal.

None of this 20mm hype makes sense for these countries to added weight for something that is such alleged limited value. They were not that dumb.

After the SB2C all USN aircraft that entered service had 20mm. The F6F5 entered service before the SB2C-4. The last corsairs entered service after the SB-2C-4 and had 4 x 20mm.

So it was solved for one plane. Apparently that did not translate to we have a solution for all aircraft.

Yeah, right so the fact that Bob Johnson got home with pieces from his air cooled radial shot off proves what, exactly? I'm still waiting for your evidence that your initial claims are accurate

So what you point? You act like 1 Spit with 20mm =death ye a book with more than 1 plane damaged with more than 1 20mm hit coming home US valueless info. Pick your argument basis an I will live with it, if you do.

Since I keep getting responses to text book answers:

When you name a shell name also planes brought down and what the gun setup was... Otherwise there is no way to discern the factors that are important its just a bunch of data.

Someone please cite number of fighter brought down with 20mm vs ...50cal otherwise you are living in a textbook world which rarely equal combat.

I am trying to generalize the .50 cal vs 20mm debate and the only data to date is a few websites with textbook data, 1 pic of a spit with 20mm damage, volumes of type of 20mm and gun data, the WISH the USN wanted to change but never put on high enough priority to get in quantity production in WWII, and no 3 or 4 planes with short runs and some mixed armament are not quantity in WWII. Say 10,000 planes with 20mm and that is different, the US built ~99,000 planes in 1944 alone.

I had to like this posting. Anything that makes me laugh must be a like.

Do you go around your some fixing something that is not broken?

 

[Shortround6]

"Wow cant search or read"

Thats another way of saying what I have been. It worked therefore not a major concern to switch so they did not.

The Navy WAS switching, so I guess it must have been a concern.

The US ordnance dept. dropped the ball. Recovery took a while. Concerns over standardization and mass production (and training) topped getting more effective weapons. This is seen in other weapons, like tanks,

Also the F86 had fuselage mounted guns so effective range went out much farther. Another reason for then the .50 setup was acceptable.

And that has exactly what to do with WW II aircraft guns?

And what happens when you put the 20mm Hispano guns in the fuselage? Does their effective range go down?

The six .50s in the Sabre were so acceptable that the Air Force started Project 'Gun Val'

Cannon-Armed F-86Fs

Wow cant search or read The Supermarine Spitfire MkIX
F IX Merlin 61; 63 or 63A; two 20-mm. and four .303-in. guns.
LF IX Merlin 66; two 20-mm. and four .303-in. guns.
LF IX (e) Merlin 66; two 20-mm. and two .5-in. guns.
HF IX Merlin 70; two 20-mm. and four .303-in. guns.
HF IX (e) Merlin 70; two 20-mm. and two .5-in. guns.
PR XI Merlin 61; 63, 63A or 70.
F XVI Merlin 266; two 20-mm. and two .5-in. guns.
Appears about half were .50 options the other half everything else .

WoW. Different versions but no comparison of actual numbers produced of each variation.

First MK IX Spitfire built in June of 1942, 5656 built, how many with .50 cal guns?
First MK XVI built in Oct 1944. 1054 built.

Now can you tell us WHEN the .50 cal guns began to be installed?

And of course the MK IX and MK XVI made up what percentage of the Spitfires built?

AN/M3 in aircraft .50 cal was 61 lbs vs 58 lbs for the MGFF so 2 lbs... wow
you also lose 290 M/S velocity (890 vs 600) which does (did) make a different in battle.

WOW is right. when did the AN/M3 .50 cal make it into an airplane? 1945?
When was the MGFF being installed in aircraft? 1940?

Try doing a just a little bit of research.

 

[Shortround6]

Someone please cite number of fighter brought down with 20mm vs ...50cal otherwise you are living in a textbook world which rarely equal combat.

well, lets see,......
How about just about every Axis plane shot down by a British fighter after the Spring of 1941?

Blending in other countries 20mm guns, I would venture to say that a large number of the planes shot down by Luftwaffe fighters were brought down by the 20mm cannon, unless you think that the pair of 7.9mm machine guns were doing the majority of the damage. Same goes for the Japanese Zero. How many planes shot down the the Russian LA-5 in 3 years?

And so on.

There was a lot of "data" sorting it out takes some doing but since EVERY SINGLE Air Force that any choice AT ALL except the US Air Force went to the 20mm gun in some form I can just assume that EVERY ONE of these Air Forces except the US Air Force was in error with all the data they had collected.

You might also want to try reading a few books rather than depend on the web.

The British built over 15,000 Spitfires with 20mm guns.

A few thousand Typhoons with 20mm guns.

well over 1000 Tempests with 20mm guns by wars end.

Almost 6000 Beaufighters.

At least a few thousand Mosquitoes with 20mm guns.

I think that the British alone seem to have well over the 10,000 plane you ask for.

As for the accuracy of some of your statements " the US built ~99,000 planes in 1944 alone"

Really? care to tell us what they were. The US built a total of 36,614 fighters of the eight major types in 1944. That only leaves another 62,386 planes to be made up of bombers, trainers, flying boats, and maybe gliders?

 

[JtD]

When was the MGFF being installed in aircraft? 1940?

1937.

 

[Matt308]

Gentlemen, as I noted in the air-to-air combination thread, in the future please take the snarky comments out of your posts please. Thanks.

 

[Glider]

But wanting in the time of war has to be prioritized with resources other needs and expected results etc.

I will expand on my original statement. The .50 was sufficient for WWII. That is not saying the .50 setup was better but good enough. Good enough implies the powers that be at the time viewed a change would cost more than the benefit.

But the USN did go the extra mile and did all they could to install the 20mm. The first Helldivers had 4 x 0.5 but despite all the difficulties went with the 2 x 20mm until it was fixed on the -4 version. Clearly they thought the cost was worth the effort. If we believe you they wouldn't have bothered. Its a problem for you to explain

Yes The US navy wanted a near one shot kill.

And the USAAF with the P61. Why would they do that if the 0.5 was good enough?

Meanwhile every major player in WWI had used .50s as some or all of their armament on their planes.

And all of them moved to 20mm where possible. Interesting why would they do that if the 0.5 was good enough?

None of this 20mm hype makes sense for these countries to added weight for something that is such alleged limited value. They were not that dumb.

The Germans replaced the LMG with a HMG, The British replaced the LMG with an HMG. No one replaced a 20mm with an HMG

So it was solved for one plane. Apparently that did not translate to we have a solution for all aircraft.

Apparently it did. No USN aircraft that entered service after the (4) version of the Helldiver had 0.5in, they all had 20mm.
You know this, why do you say this only applies to one type?

I am trying to generalize the .50 cal vs 20mm debate and the only data to date is a few websites with textbook data, 1 pic of a spit with 20mm damage, volumes of type of 20mm and gun data, the WISH the USN wanted to change but never put on high enough priority to get in quantity production in WWII, and no 3 or 4 planes with short runs and some mixed armament are not quantity in WWII. Say 10,000 planes with 20mm and that is different, the US built ~99,000 planes in 1944 alone.

What you have is one person who constantly made claims which are so wrong its untrue. Examples:-
a) The USN only wanted the 20mm for range
b) The 20mm didn't penetrate as well as the 0.5
c) The 0.5 is better against hard things
d) That the USN only fixed the 20mm for one type of aircraft (its a gun)
e) Because he has film of aircraft being shot down means that everything is wonderful. The fact that the films will only show planes going down is ignored.
f) A person who often never supports any of this.

I could go on. but that is enough for now

 

[Aozora]

But wanting in the time of war has to be prioritized with resources other needs and expected results etc.

I will expand on my original statement. The .50 was sufficient for WWII. That is not saying the .50 setup was better but good enough. Good enough implies the powers that be at the time viewed a change would cost more than the benefit.

None of this 20mm hype makes sense for these countries to added weight for something that is such alleged limited value. They were not that dumb.

Apparently every other country, apart from the U.S was dumb enough to accept the added weight and effectiveness of 20mm over .50 cal so , unlike you, they recognised that "good enough" was not "good enough" and that .50 cal was not "sufficient" for their purposes.

So what you point? You act like 1 Spit with 20mm =death ye a book with more than 1 plane damaged with more than 1 20mm hit coming home US valueless info. Pick your argument basis an I will live with it, if you do.

This is more evidence of the effectiveness of the 20mm than you have ever shown: in the meantime please show us your evidence for the definitive statements you have made which have ignited this whole "debate".

 

[zjtins]

After pulling out of an uncontrolled spin and with the fire amazingly going out on its own, Johnson headed for the English Channel, but was intercepted by a single Fw 190. Unable to fight back, he maneuvered while under a series of attacks, and although sustaining further heavy damage from both 7.92mm and 20mm rounds, managed to survive until the German ran out of ammunition, who, after saluting him by rocking his wings, turned back. His opponent has never been identified, but Johnson could have been one of three victories claimed that day by the commander of III/JG 2, Oberst Egon Mayer.[2] [N 1]After landing, Johnson tried to count the bullet holes in his airplane, but when he passed 200, including 21, 20 mm cannon shell impacts, without even moving around the aircraft, he gave up

.
that's 21 20m shells tell me how edfective this is and whre are the AP rounds thats been talked about? as i believe was 40% of an ordered load out.

 

[zjtins]

While your posting, would you like to support this statement of yours with some evidence?

one is explosive the other is impact. what else is there to explain?

 

[zjtins]

WOW is right. when did the AN/M3 .50 cal make it into an airplane? 1945?
When was the MGFF being installed in aircraft? 1940?
Sheez no wonder you have problems. ALL wing mounted (not hand held) aircraft .50 were AN versions. Did you honestly think they put D ring handle et al in the aircraft wings????

 

[zjtins]

WoW. Different versions but no comparison of actual numbers produced of each variation.

First MK IX Spitfire built in June of 1942, 5656 built, how many with .50 cal guns?
First MK XVI built in Oct 1944. 1054 built.

Now can you tell us WHEN the .50 cal guns began to be installed?

And of course the MK IX and MK XVI made up what percentage of the Spitfires built?

I already said half go read.

 

[zjtins]

After the Fall of 1944 the NAVY did NOT ORDER an new fighter with .50 cal guns. All fighters armed with .50 cal guns delivered in 1945/46 had been ordered prior to the end of 1944.
So a statement and no proof.

Same to you... where is you proof they ordered only 20mm versions of all aircraft ?

 

[zjtins]

How about just about every Axis plane shot down by a British fighter after the Spring of 1941?

Prove it

 

[zjtins]

You might also want to try reading a few books rather than depend on the web.

You mean like the many dozens I have read long before the internet.

 

[zjtins]

The Navy WAS switching, so I guess it must have been a concern.

But the did NOT in WWII. Production delivered .5.0 cal vastly outnumber 20mm equipped aircraft. You are argue ordered with no proof vs actual delivered which anyone can confirm.

 

[zjtins]

This is more evidence of the effectiveness of the 20mm than you have ever shown: in the meantime please show us your evidence for the definitive statements you have made which have ignited this whole "debate".

Yet I give a link showing dozens of German aircraft shot down with .50 in fraction of a second of a burst and thats not valid???

 

[zjtins]

Apparently every other country, apart from the U.S was dumb enough to accept the added weight and effectiveness of 20mm over .50 cal so , unlike you, they recognized that "good enough" was not "good enough" and that .50 cal was not "sufficient" for their purposes.

Except Germany replaced the there .30 cal with .50 cal equivalent in most instance by '44-'45 and Russia used 1x20mm and 1 .50 on the majority of there fighters. Even Japan had .50 cal in concert with 20mm for many aircraft. The Spit IX and XVI had around half with .50 with 20mm. Italians. So I guess everyone was stupid and put useless .50 cal on when they could have save the weight.

 

[zjtins]

Blending in other countries 20mm guns, I would venture to say that a large number of the planes shot down by Luftwaffe fighters were brought down by the 20mm cannon, unless you think that the pair of 7.9mm machine guns were doing the majority of the damage. Same goes for the Japanese Zero. How many planes shot down the the Russian LA-5 in 3 years?

prove it.