Clay_Allison
Staff Sergeant
- 1,154
- Dec 24, 2008
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Hi Juha,
>Pilots saw 4*.5 HMG as adequate armament against Japanese a/c and saw also that after you had run out ammo your chances to help the defence of your flat-top or your charges was minimal.
If you check the actual ammunition supply, the 4x 12.7 mm battery had 1720 rounds of ammunition while the 6x 12.7 mm battery had only 1440 rounds. What the pilot bemoaned was that the new aircraft had less ammunition, not that the extra guns fired off the same the number of rounds more quickly.
4x ,50 Browning M2 - 430 rpg, 33 s duration - 305 kg - 1,1 MW firepower - 37.5 MJ total supply
6x ,50 Browning M2 - 240 rpg, 18 s duration - 332 kg - 1,7 MW firepower - 31.4 MJ total supply
In fact, the F4F-4 example is great for showing what was wrong with the 12.7 mm Browning guns ... they were extremely heavy.
Here is an alternative battery that would have done a much superior job:
2x Hispano II - 417 rpg, 42 s duration - 305 kg - 2,1 MW firepower - 88.5 MJ total supply
What would these cannon have done for the US navy?
- They would have increased firepower by a factor of almost 2 over the F4F-3 battery (at the same weight).
- They would have increased the total firing duration by a factor of 1.3 over the F4F-3 battery (at the same weight).
- They would have increased the total ammunition supply by a factor of 2.4 over the F4F-3 (at the same weight).
- It would have increased firepower by more than 20% over the six-gun battery of the F4F-4 (at lower weight).
So whatever way you look at it, the 12.7 mm Browning armament was inferior to contemporary cannon, and replacing it with a different type of gun would have had considerable performance and tactical benefits for the US forces.
>Pilots saw 4*.5 HMG as adequate armament against Japanese a/c and saw also that after you had run out ammo your chances to help the defence of your flat-top or your charges was minimal. And without flat-top... Simple as that.
Taking a second look at this statement, I find it to be a very good illustration for the danger of using the term "adequate" ... I know that you meant to describe the firepower of the four-gun battery which against unarmoured Japanese aircraft with unprotected fuel tanks, against which it obviously was lethal, but what you wrote - inadvertently, I guess - actually was "adequate armament".
As the weight and the available ammunition supply have to be judged along with firepower, and weight and ammunition supply were basically "much more than adequate" and "much less than adequate" respectively, the battery as a whole was "far from adequate". As the survival of an entire aircraft carrier depended on the quality of the guns of its fighters, your example is a great illustration that having obsolete and overweight aircraft guns is a problem even for the side that is winning the war.
Regards,
Henning (HoHun)
Hello Kurfürst
if you don't have seen anything that would suggest a 'second' back plate on any Spitfire models, why not take a look on page 101 in Price's Spitfire. A Complete Fighting History (1997)And in Morgan and Shacklady p. 289 Modification 1193 for Mk VIII: Split armour for rear protection, it may well indicate to the armour layout that is in Price's book.
BTW Morgan and Shacklady gives armour weight for Mk V as 73 lb. And for PR Mk XI no armour weight but same fuel capacity in fuselage tanks as in Mk IX which indicates that self-sealing isn't counted in armour weight.
It might well be that rear armour protection in Spitfire was reinforced in stages.
Juha
The US Military had a rare bout of idiocy (rare at the time, they are more practiced now) where concerns the 20mm HS Cannon. Someone somewhere never realized that they were making a giant machine gun, not artillery and that tolerances would have to be finer to account for headspacing a cartridge at a high (comparatively) rate of fire. As a result, British guns, made with close tolerances, worked fantastically well. American guns were using greased ammunition to prevent them blowing themselves up when they were used, but mostly they were not used.
We were lucky in that my personal hero John Moses Browning designed the greatest and most enduring heavy machine gun of all time for us to chew up opposing airframes. We were equally lucky that we had no need to shoot down any heavy bombers like the Germans, British, and Japanese did.Yep, practically a miracle that the US won the war and shot down all those Japanese and German AC armed with their superior cannon while the US was stuck with the outmoded, obsolete, overweight and merely adequate weapons. I wonder if any German or Japanese fighter plane had an edge in kills over an American fighter. I can think of a few that might not have done well. P39 in the Pacific and the P38 in the ETO. But wait, both of them were armed with cannon. Oh well, when one side has superior technology in AC and better trained and more aggressive pilots, they are bound to win.
Hi Clay,
>Cannon armament is nice but it only becomes really vital when you need to knock a B-17 out of the sky.
That's a popular fallacy. Heavy machine guns were overweight and limited the capabilities of any aircraft that employed them. The extra weight was bad for fighter manouvrability and performance ... every US fighter that was shot down because it was not fast enough, couldn't climb well enough or didn't evade nimbly enough had been hampered by its own armament. And for those of them that would almost have escaped, the extra weight of the heavy machine guns alone was was killed them.
By this analogy all the LW fighters shot down with lower weight, higher performance weapons - went down because of a/c with basic inferior performance or substandard pilots..??
Even US bombers fell victim to the overweight of the US fighter guns ... whenever they were left in a tight spot because their fighter cover had to turn back for lack of fuel, they were exposed to enemy attack because the fighters did not carry as much as fuel they might have with more modern and weight-efficient guns.
Or because they were not designed to escort their bombers to maximum range. By this anology the LW should have stripped all armament from the 109 to further increase the range range over England??
Just have a look at this comparison:
6x ,50 Browning M2 - 400 rpg - 438 kg - 1,7 MW firepower
2x MG 151/20 - 250 rpg - 191 kg - 2,5 MW firepower
Going to a modern 1940s' armament option yields a weight advantage of 247 kg or about 545 lbs. These 545 lbs, had they been used for fuel, would have enabled the P-51D to extend its coverage by about 58 minutes at maximum continuous power at 25000 ft - almost one hour!
It boggles the mind to contemplate that the Mustang somehow managed to destroy the Luftwaffe over Germany with diminished range and inferior aircraft and inefficient weapons??
Being stuck with early 1930s' guns instead had many bad effects on tactics and operations, and undoubtly cost the US quite a number of fighters, bombers and a host of aircrew who were shot down because they were fighting with poor weaponry.
US pilots were incredibly brave (and stupid) to fight with such handicaps - probably substandard retards?
To assume that guns with objectively poor technical parameters did not make a difference to the worse just because the US forces "never had to shoot down heavy bombers" is rather naive - reality is more complex and less flattering than that.
Regards,
Henning (HoHun)
You know, I need to ask a friend of mine how much weight might have been saved if as much of the M2 as possible would have been made from aluminum (pretty common to use aluminum in guns these days). The US had plenty of aluminum and I can think of several large heavy parts that could be milled from aluminum.Hi Clay,
>Cannon armament is nice but it only becomes really vital when you need to knock a B-17 out of the sky.
That's a popular fallacy. Heavy machine guns were overweight and limited the capabilities of any aircraft that employed them. The extra weight was bad for fighter manouvrability and performance ... every US fighter that was shot down because it was not fast enough, couldn't climb well enough or didn't evade nimbly enough had been hampered by its own armament. And for those of them that would almost have escaped, the extra weight of the heavy machine guns alone was was killed them.
Even US bombers fell victim to the overweight of the US fighter guns ... whenever they were left in a tight spot because their fighter cover had to turn back for lack of fuel, they were exposed to enemy attack because the fighters did not carry as much as fuel they might have with more modern and weight-efficient guns.
Just have a look at this comparison:
6x ,50 Browning M2 - 400 rpg - 438 kg - 1,7 MW firepower
2x MG 151/20 - 250 rpg - 191 kg - 2,5 MW firepower
Going to a modern 1940s' armament option yields a weight advantage of 247 kg or about 545 lbs. These 545 lbs, had they been used for fuel, would have enabled the P-51D to extend its coverage by about 58 minutes at maximum continuous power at 25000 ft - almost one hour!
Being stuck with early 1930s' guns instead had many bad effects on tactics and operations, and undoubtly cost the US quite a number of fighters, bombers and a host of aircrew who were shot down because they were fighting with poor weaponry.
To assume that guns with objectively poor technical parameters did not make a difference to the worse just because the US forces "never had to shoot down heavy bombers" is rather naive - reality is more complex and less flattering than that.
Regards,
Henning (HoHun)
The M2 .50 is one of the most common and available weapons on earth and while it wasn't perfect, you know what it does. It's just a solid, workmanlike gun.Saw a news report the other day on a French corvette or something similar on patrol off the coast of Somalia looking for pirates and it showed one of it's gunners sighting on a ship they were checking. Lo and behold the idiots who designed the ship had put an M2 BMG on board, probably more than one and just think the best MBT in the world still has the old Ma Deuce as one of it's main weapons. Go figure!
Well the M2 was a scaled up 1919 so it makes sense you could scale it up again to 20mm.Hi Clay,
>You know, I need to ask a friend of mine how much weight might have been saved if as much of the M2 as possible would have been made from aluminum (pretty common to use aluminum in guns these days).
Hm, interesting thought. If you could share your friend's answer, that would be appreciated!
Historically, the route to improved firepower for the 12.7 mm Browning was to increase rate of fire. The Korean War era Browning M3 was a significant improvement in this respect.
However, if you look at the Mustang's battery, more than half of its total weight were ammunition, and a lighter or faster firing weapon can only bring a limited benefit.
6x ,50 Browning M2 - 400 rpg - 438 kg total, 264 kg ammunition
The total energy content of 20 mm rounds - MG 151/20 as well as Hispano - was roughly twice that of 12.7 mm rounds, so a change to a larger calibre with more capacity for explosives would have allowed cutting down the weight of ammunition for a certain effect on the target by one half.
As this is the larger share of the battery's total weight, it would seem more promising to go this route. As Tony Williams pointed out, the Japanese successfully up-scaled the 12.7 mm Browning M2 to 20 mm as the Ho-5 cannon, showing a feasible route the US might have taken too (even if just as a back-up option in case of the Hispano not working out as intended).
The Ho-5 had some problems in service as well, but considering the small industrial base and limited metalurgical options the Japanese had, it's quite possible that development of an analogue cannon in the US would have posed no problems of this sort.
Regards,
Henning (HoHun)