And the bullet was designed to tumble NOT penetrate, an unknown fact.
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And the bullet was designed to tumble NOT penetrate, an unknown fact.Out of the eight guns 3 were often loaded with ball (lead core) ammunition
Nope.
How many veterans that flew P-38s in fall of 1943 and early 144 would tell you that you were supposed to cruise a P-38 at high rpm and low boost?
A lot of those men were not gunnery experts, they were repeating what they had been told.
Or listed to some veterans talk about the .45 automatic pistol and how inaccurate it was.
The British had very good reasons for skipping the .50 cal until late in the war, and some of the those reasons go back to before WW II started and carried through until 1942-43. But you want to ignore those reasons?
One of the reasons was that they didn't have the money/production facilities for both the 20mm cannon and the .50 cal guns. When they started putting .50 cal guns into Spitfires they were getting the guns and ammo lend-lease. No British gun factory, no British workers, a fair amount of the ammo from American factories. Makes the choice a whole lot easier.
British broke ground for the 20mm gun factory in 1938.
Are you confusing this discussion with some other thread? I wasn't arguing against the British use of the 20mm, or their initial adoption of the .303. (Almost) everyone was using light .30 caliber machine guns at the dawn of WW2. At least the British put a lot of them on their newer fighters, and quickly adopted cannon.Now since the British were phasing out the .303 in the fall of 1940/spring of 1941 and sense most of their experience at that time was due to the BoB I am not sure why you are so quick to bypass the BoB, since that is the basis for your argument against it.
Now as you well know the fuel tanks in the P-40s wing were pretty much under the cockpit and the pilot in the photo is standing on empty space. I don't have any other photos so I don't know if the 3 shells that hit the wing went up the belly where the fuel tanks were or hit outside the wheel wells a number of feet away from the tanks.
Germans used two different 20mm shells in the MG 151/20 gun. The famous mine shell with 20 G of explosive filler but not much metal and the HET round that held about 3.7G of HE. (the tracer took up some space). A 20mm Hispano HE round held 10.2-10.5 grams of HE.
The Round in the photo looks like it exploded just about where the fuselage skin was, Not against the armor plate behind the pilot. Both the German and the British had a lot of trouble with bad fuses, both number of duds and the with shells exploding too soon and not inside the aircraft. Things got better latter but not perfect.
As far as kinetic energy goes, the MG 151/20 had about 62% of the energy that the Hispano had.
Let's try to compare apples to apples.
I have found several other photos. like the 20mm strike in the port aileron.There are several other photos, and in fact a video, but my google-fu is failing me. He is a pilot of the 79th Fighter Group, I thought his named was George Mobray or something like that.
It's really easy to see in the photo that the round detonated inside the fuselage, you can see the aluminum alloy peeled back above and below. Shrapnel definitely hit the fuselage fuel tank which is right there, and also definitely hit the armor plate which is exactly at that point. But this isn't exactly unusual.
An experimental Hellcat with a fuel tank in the wing?A hellcat with cannon holes in the port wing, which definitely hit the fuel tank.
And you can tell the fuel tank was punctured how?. The fluid on the fuselage is apparently oil though it's likely the rear fuel tank was punctured as well.
I really think you have lost the plot here mate.
Yes, that's the same guy, same plane, but not the only other hit right? Do you have a link? There is (or was) a short video on Youtube as well but I don't recall the search terms.I have found several other photos. like the 20mm strike in the port aileron.
View attachment 675180
But that isn't close to the fuel tank is it?????/
I'm just calling it like I see it, not the other way around.You see what you want to see. Like.........................................
Ok fair enough, that was an assumption on my part. Just like you assumed for some bizarre reason I was criticizing the Royal Air Force's choice of armament in the BoB.An experimental Hellcat with a fuel tank in the wing?
Hellcats had the fuel tanks in the fuselage. the damage on the photo was in the machine gun bay.
And you can tell the fuel tank was punctured how?
BTW the Tomahawk had the oil tank above the rear fuselage tank. On the Kittyhawk the oil tank was moved forward to just behind the firewall, where the fuselage 50 cal ammo used to be.
I think you have posted a number of photos with your own interpretations and none of them show the damage a 20mm Hispano caused.
It was a more powerful gun and from 1943 onwards the belts were predominantly 50/50 HEI/SAPI, they are nasty rounds to an aircraft.Are you saying that Hispano did a huge amount more damage than an MG FF, Oerlikon, or MG 151?
In you look at successful versus unsuccessful implementations, the Hispanos issues make sense.I already pointed out that the US wanted to use 20mm, they had an unusual degree of difficulty to get them working (again for reasons I still don't fully understand). I guess some places were better at borrowing some of these excellent Franco / Spanish / Swiss design concepts than others.
Hey Wild_Bill_Kelso,
Thanks for the source re the Seafire sometimes having reduced ammo loads for performance purposes.
re 20mm vs .50 cal
Maybe I missed something, but I thought the main contention came from the statement that 1x 20mm was worth 2-3x .50 cal, a statement made by the USN operational research. Since all the major combatants came to the same ~conclusion, I do not see that there is any basis for the argument that the statement is not correct.
I realize that the energy output is greater for 6x .50 cal than for 2x 20mm IF YOU ARE FIRING SOLID PROJECTILES and talking only of kinetic energy, but if you add in the equivalent chemical energy supplied by the explosive content of the 20mm HE projectile, then using your math we get:
six 12.7mm Browning = 78 rounds per second, at 43 grams, a 'weight' of 3,354 grams, or 3+ kg at 890 m/s = KE of 1,328,351.7 Joules
two 20mm Hispano II = 20 rounds per second, at 122 grams, a 'weight' of 2,440 grams, or 2+ kg at 860 m/s = KE of 902,312 Joules + CE of 20 x 8 x 4180 = 902,312 + 668,800 = 1,571,112 Joules
NOTE that I subtracted 8 grams from each 20mm projectile in terms of kinetic energy and added 8 grams of TNT equivalent chemical energy at 4180 Joules/gram TNT.
That makes sense, and they actually had similar problems with the 12.7mm (and I think, .30 cal) in the wings, for similar reasons, but with the 20mm the Americans had other problems. They had issues with fuselage mounted 20mm all the way into the Vietnam era. I think there was something to do with a firing pin. I'm not sure what else.In you look at successful versus unsuccessful implementations, the Hispanos issues make sense.
The gun was designed to be mounted to an engine block (motor-cannon). And it works as designed when mounted firmly - the test stand, the nose of a P-38, the belly of P-61 or P-70, and even in the wings of a SB2C.But when you mount in the wings of a fighter, it doesn't operate reliably because the wings flex and as a result the action does cycle completely.The RAF solution was to shorten the chamber, which would crush the cartridge in a solid mount, but worked just fine in the wing mounts.Why the USAAF refused to make this expedient fix is the real question.
Again, I don't think that physics works that way. You don't just add the HE energy to the ballistic energy like that. The HE has some different effects which are both good and bad. It can hit even with near misses, which is good, but it can detonate before penetrating, which isn't always helpful.Rerunning your numbers to add the CE for the 0.5, and that 8% of 130g is closer to 10g of HE.
six 12.7mm Browning = 78 rounds per second, at 41 grams, a 'weight' of 3,276 grams at 890 m/s + CE of 78 * 1 * 4,180 = 1,297,40 + 326,040 = 1,623,500 Joules
two 20mm Hispano II = 20 rounds per second, at 122 grams, a 'weight' of 2,400 grams at 860 m/s = KE of 887,520 Joules + CE of 20 x 10 x 4180 = 887,520 + 836,000 = 1,723,520 Joules
So, closer, but 2 Hispanos still trumps 6 - 50s. (And I think the HE should be counted as part of the initial KE as its part of damaging mass right up to ignition.
In Mosquito, Tempest and Typhoon at war, the bean counters noted, that post D-Day on average, the planes were coming back with less than 1/2 ammunition expended. So, they reduced load outs to 60%. (Lies, damn lies and statistics) much to the dismay of the pilots involved.
Yeah, they aren't the 'same' and I certainly never said they were. But my argument was that the Hispanos didn't have vastly more impact than other 20mm cannon, enough to invalidate the point I was making (fighter aircraft could and did survive cannon strikes). Specifically compared to German cannon:Hi
Yes not all 20mm guns were the 'same' and not all 0.50 in/12.7mm were the 'same' in performance. Their effectiveness would depend on a variety of factors which included muzzle velocity, rate of fire, reliability and more important the effectiveness of the rounds used. All these factors could differ in one individual design let alone mulitble designs, early US aircraft 0.50 in were 'worse' than later ones, the different marks of Hispano guns also differed, a brief summary from 'British Aircraft Armament Volume 2' by R Wallace Clarke:
Also a brief summary of aircraft guns from 'Aircraft of the Second World War, The Development of the Warplane 1935-45' editor Philip Jarrett:
The whole thing about Seafire v Corsair is odd because they were not 'competitors', indeed the Corsair and Hellcat should have been 'better' naval fighters as they were designed as such and were introduced later than the Seafire. The Seafire was introduced into service in June 1942 and was first used operationally in November 1942, FAA Corsairs did not arrive until June 1943 with their first operation in April 1944, the Hellcat did not arrive until July 1943 with its first operation in December 1943. The FAA could not rely on US production to fulfil its needs so used a mixture of types from Britain and the US, the Seafire, and the Sea Hurricane, provided the higher performing fighters when they were desperately needed, they were far from perfect but waiting for a 'perfect' Corsair or Hellcat to turn up was not an option to fight a war as they would easily become "too little, too late" for 1942/1943, as the Wildcat was for 1940. The FAA of 1944-45 was of course much better equipped with its mixture of aircraft.
Mike
I see a fair amount of sheet metal peeled back, I also see a fair amount of fragment holes below the large hole that look like the fragments came from the outside. Also a fair number of scrape marks radiating out from the hole in the lower arc. Unless we have two shells expanding very close to each other how to we reconcile that?You don't see metal peeled back from the inside here? Seriously?
20 mm projectiles ranged from 79 grams (Japanese army) to 130 grams for the Hispano.Are you saying that Hispano did a huge amount more damage than an MG FF, Oerlikon, or MG 151?
I think the Hispano was designed to use greased ammunition, I could be wrong on this and the grease was used as a "work around". The 20mm Oerlikon definitely used greased ammo.The RAF solution was to shorten the chamber, which would crush the cartridge in a solid mount, but worked just fine in the wing mounts.Why the USAAF refused to make this expedient fix is the real question.
There were NO M3s in 1943-44.But while we are at it, here is the stats for the M3 browning, which many US - made fighters were carrying by 1943:
six M3 12.7mm Browning = 120 rounds per second
It seems like the US was only using some 20mm Hispanos in Vietnam. In Skyraiders and few old navy aircraft.They had issues with fuselage mounted 20mm all the way into the Vietnam era. I think there was something to do with a firing pin. I'm not sure what else.
I see a fair amount of sheet metal peeled back, I also see a fair amount of fragment holes below the large hole that look like the fragments came from the outside. Also a fair number of scrape marks radiating out from the hole in the lower arc. Unless we have two shells expanding very close to each other how to we reconcile that?
Shell exploded either on the skin surface or partially penetrated? A German shell was about 80mm in length so you can have fragments (or force) applied to different sides of the same hole on thin skins. But if the shell exploded on the aircraft skin it did not hit the armor plate as an intact projectile.
Please look at the picture of the Spitfire in post #145. I would guess that the shell hit on angle judging from the fragment holes above and the lack of fragment holes below. the Sheet metal is blown in strongly suggesting a surface explosion.
On the P-40 in question there are photos (and maybe others?) that show the hit on right hand fuselage in back of the cockpit, there was another hit on the right hand horizontal stabilizer very close to the fuselage. Camera is just above the stabilizer tip so it is hard to see but looks like the shell went in just over the elevator?
Then there is the photo of the left side aileron where it looks like the shell went in through the back of aileron (deflecting the trim tab out of the way?) and exploded either in the forward edge of the aileron or the wing just in front of the hinge point )or both (80 mm long shell)
View attachment 675207
Note that the aileron is metal covered on the leading edge and fabric covered over most of it's surface.
IF (saying if) that is the entry hole in aileron visible through his fingers holding the shell fragment/plug) it looks like the shell was traveling a bit to left to where the greatest damage to the rear of the wing is. The raised up panel is blast damage (torn rivets or screws)
There are 3 photos on the 87th fighter group website, I have no idea where the extra hits went.
20 mm projectiles ranged from 79 grams (Japanese army) to 130 grams for the Hispano.
Muzzle energy ranged from 19,700 joules for the MG/FF to 46,900 joules for the Hispano (long barrel)
HE content ranged from under 4 grams to 20 grams (German mine shell)
Define "huge amount"?
Obviously there was a substantial difference between the extremes.
There were NO M3s in 1943-44.
None.
Nada
Zilch.
There were darn few in 1945.
The Gun that would become the M3 was the Frigidaire T25E3 and testing started at Aberdeen July 19th 1944. It was standardized in April of 1945. A batch of guns (up to 10,000?) were built using the T25E3 designation for large scale trials.
It seems like the US was only using some 20mm Hispanos in Vietnam. In Skyraiders and few old navy aircraft.
The US had number of 20mm guns using several different cartridge cases. Most being electrically primed.
View attachment 675212
From Anthony Williams website.
The 20x102 was the Air force ammo. The 120x110USN was US navy, these two were both electrically primed.
The 20x110 came both percussion primed for the M3 Hispano and electrically primed for the M-24 gun.
I am not saying there weren't problems with electrically primed guns in jungle conditions. But they may have been different than the percussion fired guns.
To be fair, the Corsair was the better fighter compared to the Hellcat. That's why it was the longest produced U.S. piston engine fighter - 11 years. Granted, the Corsair had some early landing issues on carriers which arguably limited deployment to Marine squadrons during the war (Navy pilots generally did not use land bases). Some of the longevity of production was likely due to the Navy's issue with the new jets, taking off/landing on a carrier. However, looking at a mid-1943 Corsair compared to a 1943 F6F-5, the Corsair was faster and had a superior roll rate than the Hellcat. Hellcat was better at diving. I'm not at all implying the Hellcat was a bad fighter, just that the Corsair was better. Both used the same R-2800 engine, but Vought's design of a slimmer fuselage, closer cowled engine, cooling ducts in the wing and flush riveting throughout made the difference. Just my humble opinion.
But if you insist, I'll go find some German aircraft which landed safely with obvious cannon strikes