Best armed fighter

[Clay_Allison]

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)

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.

 

[Kurfürst]

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.

Yes, it is possible, M+S does note that split armor in the rear, with a date for the modification of 20-12-43. Its a pity that there are no other detail about thickness and the extent of introduction to service aircraft, but I am sure it would be very useful, given that the existing 4.5mm plate was lacking in proctection offered. Unfortunately I don't have that particular Price 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 German report as of 5 February 1943 indicates the armor weight on the Mk V being 60 kg, on Mk VI being 67.8 kg vs 70.8 kg on the Mk IX. The only difference striking to the eye is that the back plate is made up by 3 seperate plates while the IX covers the same area with a single plate, plus some minor difference in the form of the cannon armor plate and head plate.

It is quite certain they received upgrades, the Germans note that the glykol tank plate and the knee-plate were both found from autumn 1942 onwards, for example.

 

[Glider]

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.

I believe that this story which does appear every now and again is not true. Indeed in the various tests that took place the UK representatives were full of praise for the quality and fit of the american produced guns which were ahead of the British produced weapons.
They didn't work, because the USA refused to apply the changes to the original design that the British had made to make it work.

 

[renrich]

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.

 

[KrazyKraut]

yawn

 

[Clay_Allison]

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.

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.

Cannon armament is nice but it only becomes really vital when you need to knock a B-17 out of the sky. Those big heavy airframes can take a ridiculous amount of MG fire.

With the US fighting mostly fighters, dive bombers, etc. we didn't really need a cannon armed interceptor. If we had, we probably would have put that T-9 37mm cannon from the P-39 in the P-38's nose.

 

[HoHun]

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)

 

[renrich]

The 50 BMG weighed substantially less than the US 20 mm and the ammunition less also. In a duel between fighters the odds of getting hits with four or six fifties are much better than with two 20 mm cannon. The British and American designers bureaus of aeronautics knew that. The British to the extent that they insisted on six fifties in the F4F4 probably because they realised that the British pilots would not have as much air to air gunnery training as the USN pilots.

 

[drgondog]

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)

LOL

 

[Clay_Allison]

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)

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.

Also I think using lighter weight explosive ammo would have made it more comparable to the German 13mm guns.

 

[renrich]

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!

 

[Juha]

Hello Kurfürst
thanks for the details from German reports. M+S book is sometimes infuriating, giving wonderful details on some one-offs but not revealing some fundamentals as the exact details of different armour schemes. And lack of good index made searching info from it sometimes very haphazardly.

Hello HoHun
USN was interested in Hispano but didn't want to heed British advices but wanted to solve problems themselves and so their 20mm cannon was at first very unreliable and when they got it more or less ready for service naval and IIRC also MC pilots preferred 6*.5 HMGs (F4U-1D) over 4*20mm (F4U-1C). Pilots seemed to think that 6*.5s was better in air combat but in strafing 4*20mm might have its merits.

Hello Renrich
one reason why RN demanded 6*.5s for F4F-4 was that one main enemy of their fighters was FW 200 Condor.

Juha

 

[Clay_Allison]

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!

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.

 

[HoHun]

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)

 

[Clay_Allison]

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)

Well the M2 was a scaled up 1919 so it makes sense you could scale it up again to 20mm.

You also could have loaded the M2 with HE rounds as well. PETN weighs less than lead, and the 750 grains of lead is most of the weight of the ammunition.

 

[renrich]

The first Condor shot down by a Wildcat was on Christmas Day, 1941, by a F4F3 with four guns and of couse the FM2 reverted to four guns. An interesting statement by Eric Brown in his comparison of the 109F versus the Wildcat. "The Wildcat had a heavier punch to deliver." He apparently believed that the wing mounted six fifties of the Wildcat were superior to the two rifle caliber Mgs and the 20 mm in the nose.

 

[HoHun]

Hi Clay,

>>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.

>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.

Note that the main defect of the 12.7 Browning M2, its heavy weight, has a quite different priority in an aviation context than in an armour or even naval context.

Six guns in a 5-ton-fighter that has to fly is not the same as one gun in a 50-ton-tank in a tank that doesn't have to fly, or any number of guns in a 3000-ton-ship.

Regards,

Henning (HoHun)

 

[renrich]

No question that weight of a gun plays a great deal more of a role in an AC where every pound saved, especially in WW2 AC, is precious. The point made in my post on the BMG in the present is that if it were not extremely effective, it seems like it would have been supplanted or at least seriously modified. The ones I have seen in newscasts in Iraq and other areas seem to be identical to the one I used in 1960.

 

[claidemore]

On the subject of .50 BMGs shooting down heavy bombers, I believe the Royal Navy Martlet I/Wildcats (with 4x.50s) shot down several FW200 Condors, a heavy 4 engine bomber. (as renrich pointed out)

Me323's also fell victim to P40's in North Africa, (I believe James 'Stocky' Edwards got 2 or 3 in one mission?)

There were also a host of twin engine bombers that fell to .50 Brownings, both German and Japanese.

Also, Anabuki Satoru shot down two P38s and two B24s with the twin 12.7mm guns on a Ki-43 (then rammed another B24 to become an "Ace in a Day")

This belief that .50s were ineffective (against bombers) seems to stem from poor results in the popular IL2 series of flight sims rather than real life results.

 

[HoHun]

Hi Claidemore,

>This belief that .50s were ineffective seems to stem from poor results in the popular IL2 series of flight sims rather than real life results.

What the real-life data right from Tony's site clearly shows is that the 12.7 mm Browning was inefficient, overweight and behind its times:

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
2x Hispano II - 417 rpg, 42 s duration - 305 kg - 2,1 MW firepower - 88.5 MJ total supply

Pick any Luftwaffe or Allied cannon, plug in the data, the result is always the same - the 12.7 mm Browning provides significantly less firepower for significantly more weight.

Regards,

Henning (HoHun)