Allied airframes, German parts

[Lighthunmust]

Any large four engined bomber on its own was vulnerable to almost any fighter. The difference is when your attacking a bomber stream of three to four hundred bombers plus and are likely to only get one pass at a particular bomber. In this scenario the P47 with its eight x 0,50 has reasonable firepower but not the ideal firepower to take on an aircraft like the B17. Japanese and Germany 4 engined aircraft were normally not just alone but were also far more fragile than a B17 so hardly a fair comparison.
The P47 had roughtly the same punch as a Spit with 2 x 20mm and 2 x 0.5, the Fw190 with 4 x 20mm and 2 x HMG had more firepower and that wasn't considered sufficient for a one pass kill. All forces that went up against massed B17's considered 4 x 20mm to be the minimium and there is no getting away from that.

A couple of observations about the 0.50M2,it was a good weapon but by no means the best of its calibre. If you believe in the HMG as the weapon of choice, then the quckest and easiest way of improving the P47 firepower is to take out the 8 x M2 and replace them with 8 Russian 12.7mm UB. It is lighter, has a much higher rate of fire approx 30% higher, fires a larger projectile at a similar MV.

One other observation, you mentioned earlier that the USAAF were happy with the M3 in Korea. That might be the case with the USAAF but the USN much preferred the 20mm. Even during WW2 the all USN F6F5 Hellcats were capable of being armed with 2 x 20mm and 4 x HMG, that they weren't wasn't a matter of choice, more a matter that the US 20mm guns were very unreliable.

I think you need to re-read my posting you are referring to. To save you the time I will summerize:

Aircraft critical structures are much more difficult to inflict catastrophic damage to than pilots and co-pilots

One .50cal bullet is enough to kill a pilot and one more is enough to kill the co-pilot.

M2 .50cal MGs shoot more bullets out at the pilot in a firing pass than the 20mms.

More bullets equal greater chance of hitting and killing the pilot and co-pilot.

Dead pilot and co-pilot equals out of control bomber.

Out of control bomber destroys itself when it crashes into another bomber in box or the ground.

I have actually fired a russian 12.7mm machine gun (Dshk) and am well aware of the qualities of the UB from the book I have sited. Unfortunately, UBs from the USSR were not reverse lend-leased to the USA. Perhaps that would have been a good thing.

On the contrary, I never mentioned the USAF was happy with the M3 in Korea. My posting clearly infers that they failed to realize that .50 caliber ammunition fired from any gun would not be adequate after WW2 for future needs.

I like 20mm cannons! They were the wave of the future post-WW2. I have an actual, live, unfired WW2 era 20x138B cartridge on a shelf in my den (legally owned in Arizona, USA). I acquired it because I had a friend thirty years ago that owned a 20MM cannon he let friends fire for $30.00 a bang. As a college student, I worked part time in a gun shop that also owned a L-39. Have stood on the ground watching what the cannons on a AC-130 can do. I really understand the power of cannons. That being said, what the Luftwaffe had was still not routinely effective, on any given firing pass, at destroying bombers structurally. In reality they had not much choice in sticking with the cannons. They needed an armament package that was more efficient at destroying bombers by killing pilots. I believe lots of .50 bullets being fired into the front of the cockpit would be that package. Any of those bullets missing the pilots and hitting the engines and fuel tanks would be a bonus.

 

[tyrodtom]

Any bullets fired from the front toward the cockpit is also going toward the bomb bay. Even though the bomb fuzes aren't armed, the fuzes safety features can be overcome by the brut force of a bullet hitting it.

 

[davebender]

If it penetrates the armor and if it hits the pilot. Otherwise one .50cal bullet is likely to accomplish little. A 2cm or 3cm mine shell is likely to cause serious damage whether it hits the pilot or not.

 

[Shortround6]

Lets look at this just a little more carefully shall we. Luftwaffe figures that an average pilot hits a 4 engine bomber with 2% of the rounds fired. How big is the 4 engine bomber? This isn't working too good ( or working as well as hoped for?) so the plan is to aim for just the cockpit area? Gee, I wonder what the hit percentage was for that? Granted the Luftwaffe did figure that a lot fewer 20mm shells were needed in the cockpit area than spread out over the whole bomber. The problem is getting those rounds into the cockpit in the first place.
Anecdotes are nice but they are not hard evidence. Even if 5 pilots made it back after taking a 20mm to the cockpit that doesn't tell us how many didn't or what the percentage of cockpit hits to planes downed was. One incident is too small to base a position on.
As far as the "lesser quantity" goes that is true but six .50 cal guns put out just over twice the rounds per second that 4 20mm Hispanos do. And that is the slow firing Hispanos.

having 6 20mm shells hit a plane instead of 12 .50 cal rounds might be described as ""devastating". No single round of ammunition that could be fired by a single or twin engine plane could absolutely guarantee 100% success in all circumstances. At least one B-17 made it back after a direct hit by a 75mm or 88mm projectile. A Henschel 123 was supposed to have survived a direct hit by an anti-aircraft shell. Does that mean we should have gone back to 7.62 guns because they could put out so many bullets?

 

[Lighthunmust]

If it penetrates the armor and if it hits the pilot. Otherwise one .50cal bullet is likely to accomplish little. A 2cm or 3cm mine shell is likely to cause serious damage whether it hits the pilot or not.

And yet many 2cm and 3cm never hit anything and many pilots were never hit because there were not enough 20s or 30s flying through the air to increase hit percentage. Not just because of not enough German aircraft. Cannon firing rates were slow and slower, firing times were short and shorter. No doubt a projectile from a 20mm and 30mm has much greater potential destructive power than a .50, but like people most never realize their full potential. Again I'll ask. Anyone remember that Robert Johnson had a 20mm explode in his P-47 cockpit and still flew home?

There was armor plate protecting the B-17 and B-24 pilots immediately behind the instrument panel. Other than that the pilots were very exposed to penetrating heavy machinegun fire. That armor certainly had the potential to stop bullets but also had the potential to greatly reduce the effectiveness of 20mm under less than ideal conditions of impact.

With the short engagement time, crude fire control equipment, low cyclic rates and ammunition supply, cannons were not necessarily the right answer for bringing down (as opposed to destroying the airframes) heavy bombers.

 

[Shortround6]

I'd rather have a reliable R2600 during 1940 then a reliable BMW801 during 1943.

SO would most people, now try building a fighter around the 1940 R-2600 and getting it to run on German fuel. Critical hight of the 1940 engine is 11,500ft, 2400 rpm, all of 1400hp. It is a bit better than a Merlin giving 1310hp at 9,000ft but the Merlin is 3-400lbs lighter (including radiators), and has less drag and sucks less fuel. You only have to figure out how to fan cool it or you are really going to have drag problem.
BTW the 1940 R-2600 could use 1.3 ATA of manifold pressure for it's MAX CONTINUOUS power setting.
Air cooled engines usually needed better fuel than liquid cooled engines to use similar boost pressures.

 

[Shortround6]

. Again I'll ask. Anyone remember that Robert Johnson had a 20mm explode in his P-47 cockpit and still flew home?

So what, many aircraft were hit with larger than 20mm caliber shells (if not sometimes direct collisions with other aircraft) and made it back. However the extreme damage survivors were the exception. basing your armament on the 1-5% that make it back after getting a good thrashing rather ignores what happened to all the rest.

There was armor plate protecting the B-17 and B-24 pilots immediately in behind the instrument panel. Other than that the pilots were very exposed to penetrating heavy machinegun fire. That armor certainly had the potential to stop bullets but also had the potential to greatly reduce the effectiveness of 20mm under less than ideal conditions of impact.

Quite true but then 20mm Hispano ammunition changed during the war and 20mm Hispano ammo is not MG 151 ammo. The later (1942) SAPI rounds for the Hispano would penetrate almost the same amount of armor as a .50 M8 API round but carried 10 times the incendiary material of the US .50cal M8 API round of 1944.
German 20mm rounds often carried more explosive but the thin walls meant poor penetration and not as much fragmentation. They were better in some circumstances and not so good in other.
With 20mm Projectiles varying in weight from 79 grams to over 130 grams and MV varying from 585 to 860 meters/sec we need to be a little more selective in which anecdotes actual show what.

With the short engagement time, crude fire control equipment, low cyclic rates and ammunition supply, cannons were not necessarily the right answer for bringing down (as opposed to destroying the airframes) heavy bombers.

The cycle rates were often not that much slower. leaving out the MG-FF and it's Japanese equivalent 20mm guns fired anywhere from 70% of the rate of an American .50 to 100%.

 

[Lighthunmust]

Lets look at this just a little more carefully shall we. Luftwaffe figures that an average pilot hits a 4 engine bomber with 2% of the rounds fired. How big is the 4 engine bomber? This isn't working too good ( or working as well as hoped for?) so the plan is to aim for just the cockpit area? Gee, I wonder what the hit percentage was for that? Granted the Luftwaffe did figure that a lot fewer 20mm shells were needed in the cockpit area than spread out over the whole bomber. The problem is getting those rounds into the cockpit in the first place.
Anecdotes are nice but they are not hard evidence. Even if 5 pilots made it back after taking a 20mm to the cockpit that doesn't tell us how many didn't or what the percentage of cockpit hits to planes downed was. One incident is too small to base a position on.
As far as the "lesser quantity" goes that is true but six .50 cal guns put out just over twice the rounds per second that 4 20mm Hispanos do. And that is the slow firing Hispanos.

having 6 20mm shells hit a plane instead of 12 .50 cal rounds might be described as ""devastating". No single round of ammunition that could be fired by a single or twin engine plane could absolutely guarantee 100% success in all circumstances. At least one B-17 made it back after a direct hit by a 75mm or 88mm projectile. A Henschel 123 was supposed to have survived a direct hit by an anti-aircraft shell. Does that mean we should have gone back to 7.62 guns because they could put out so many bullets?

The answer to your last question is no. The difference in the power of a HMG projectile in comparison to rifle caliber projectile is even greater than that of a 20mm projectile to a .50 BMG projectile. I have seen your postings and seen the tables indicating a 20 is 3-4 times as powerful as a .50. A .50 is 4-5 times as powerful as a 7.62,7.92,etc. The crucial point being that both the .50 and 20mm cross the threshold of minimum necessary power.

What specific anecdotes are you referring to? Robert Johnson's experience is not anecdotal, it is documented. How are you concluding my position is untenable because "One incident is too small to base a position on"? My position is not based on "One incident is too small to base a position on".

I am sure "6 20mm shells hit a plane" on many occasions and were not "devastating" to the airframe and did not result in destruction. "Luftwaffe figures that an average pilot hits a 4 engine bomber with 2% of the rounds fired". Would you like to provide the methodology the Luftwaffe used to determine this percentage? Was it the poor quality gun camera images, remaining rounds in returning fighters versus hole counts in downed bombers. I will to bet a beer it was not analysis of only firing passes from head on. "....so the plan is to aim for just the cockpit area? Gee, I wonder what the hit percentage was for that?" Obviously a lot higher if from head on than from any other angle of attack. Getting the rounds in the cockpit is much easier when that is the primary target and the right attack angle is used.

My position is: Under the conditions of using a single engine fighter to attack U.S. heavy bomber boxes, head on passes with heavy machine guns may have been more effective due to more numerous sufficiently powerful projectiles than the primarily cannon armament of fewer more powerful projectiles that was actually used.
It may also have been a better tactic to use single engine fighters with HMG and larger magazines to attack the escorts so the twin engined fighters with cannons would not be harassed when firing shells out of the effective range of the bombers defending .50s

"No single round of ammunition that could be fired by a single or twin engine plane could absolutely guarantee 100% success in all circumstances. At least one B-17 made it back after a direct hit by a 75mm or 88mm projectile. A Henschel 123 was supposed to have survived a direct hit by an anti-aircraft shell. Does that mean we should have gone back to 7.62 guns because they could put out so many bullets?" This is so much a statement of the obvious it makes we wonder if you are trying to insult me with condescension.

The responses from several members indicates I have really struck a nerve. It is not my intention to irritate. I find your responses interesting and enlightening.

 

[Lighthunmust]

Shortround6

You are a very knowledgeable fellow. You know I have previously expressed in postings my respect for your knowledge. Are you unequivocally willing to state that machinegun armed P-47s and P-51s would have been less effective destroying american style heavy bombers in formation than cannon armed German single engine fighters?

 

[Glider]

First of all I thank you for your corrections I did misread a couple of earlier posts, my mistake.

I think you need to re-read my posting you are referring to. To save you the time I will summerize:

Aircraft critical structures are much more difficult to inflict catastrophic damage to than pilots and co-pilots

With a 12.7 yes, but a lot easier with a 20mm.

One .50cal bullet is enough to kill a pilot and one more is enough to kill the co-pilot.

True but one 20mm would almost certainly disable both, had a much better chance of penetrating, and would do a lot of additional damage.

M2 .50cal MGs shoot more bullets out at the pilot in a firing pass than the 20mms.

Depending on the 20mm. The M2 fired about 13 rps, the Mg 151 12 rps, Hispano II 10 rps, Hispano V 12.5 rps, Ho 5 14 rps, B 20 13 rps. The difference is often negligable. The Fw190 A8 fired 78 rps, 48 of them 20mm with a total weight of fire of 6.6 kg/sec the P47 would have fired 104 rps, with a weight of fire 4.4 kg/sec and this ignores the high explosive damage which was negligable on the M2 and considerable on the 20mm. However you look at it, the P47 was outgunned compared to the normal Fw 190 A8 and the Germans wanted to improve on that.

More bullets equal greater chance of hitting and killing the pilot and co-pilot.

Dead pilot and co-pilot equals out of control bomber.

Out of control bomber destroys itself when it crashes into another bomber in box or the ground.

Self evident, but as just pointed out the number of shells fired per gun was often basically the same and the destructive power of the 20mm considerably more. The USN compared the M2 with the Hispano II and in the summary said that the Hispano II was three times as effective as the M2.

On the contrary, I never mentioned the USAF was happy with the M3 in Korea. My posting clearly infers that they failed to realize that .50 caliber ammunition fired from any gun would not be adequate after WW2 for future needs.

This is where you corrected me, thanks again

That being said, what the Luftwaffe had was still not routinely effective, on any given firing pass, at destroying bombers structurally. In reality they had not much choice in sticking with the cannons. They needed an armament package that was more efficient at destroying bombers by killing pilots. I believe lots of .50 bullets being fired into the front of the cockpit would be that package. Any of those bullets missing the pilots and hitting the engines and fuel tanks would be a bonus.

I believe that the vast majority of bomber that were shot down were destroyed by fire from engines, fuel tanks and other vulnerable items on the aircraft, the Pilots were a very small target and well protected. Your faith in the ability of a pilot to hit what they aim at is optimistic, most pilots were lucky to hit the aircraft.

 

[ctrian]

Shortround6

You are a very knowledgeable fellow. You know I have previously expressed in postings my respect for your knowledge. Are you unequivocally willing to state that machinegun armed P-47s and P-51s would have been less effective destroying american style heavy bombers in formation than cannon armed German single engine fighters?

I am really surprised you're even debating this.MG would be less than uselless against 4-engine bombers it would be a waste of pilots and aircraft.Why do you think the LW upgunned the FW190 to sturmbock ?

 

[Readie]

I believe there was a Spitfire re-engined with a DB engine.

Also :-

HA-1112-M1L

The final variant was the HA-1112-M1L Buchón (Pouter), which is both a male dove or a pelican in Spanish. It first flew 29 March 1954. The 1112-M1L was equipped with the 1,600 hp Rolls-Royce Merlin 500-45[3] surplus bargain engine and Rotol propeller.[3] This clumsy though reliable "power-egg" WW2 bomber engine had a P-40-like deep chin intake, that ruined the sleek lines of the Bf 109's airframe visually. As such, this plane was an improvised assembly of outdated components for the specific purpose of controlling Spanish colonial territories in Africa where a higher level of technology was unnecessary, and moreover not available in isolated Spain at the time. Its armament consisted of two 20 mm Hispano-Suiza 404/408 cannons and two Oerlikon or Pilatus eight-packs of 80 mm rockets. It remained in service until 27 December 1965.
HA-1112-M1Ls remained in flying condition until the mid-1960s. This made them available for theatrical use, disguised as Bf 109Es and Gs in movies like Battle of Britain, Memphis Belle, and The Tuskegee Airmen. Remarkably, Buchons also played the Bf 109's opposition, the Hawker Hurricane, in one scene in Battle of Britain.

Cheers
John

 

[davebender]

Hence the reason for 20mm and 30mm mine shells. You can miss critical aircraft components such as the pilot yet still cause a lot of damage by ripping up aircraft skin. A fuel tank hit will create a hole too large to self seal.

 

[drgondog]

The P-51 had same or better performance with some individual lesser capability (climb 109, roll 190) while being faster, better range 'as is'. The limitation on the Me 109G and the Fw 190 A5 through A8 was INTERNAL fuel. The drop tanks go at first sighting of e/a - bringing endurance back to very low air time and limited options.

The LW needed high capability long range interception to increase their tactical options, at least in the West.

The P-47D-25 and above could out perform the A8 in nearly every category at bomber altitudes, was more rugged and could carry more stores externally.

The Germans could always place local superiority at the point of attack all the way through Bodenplatte. What they couldn't do from March 1944 forward is defeat the Mustang escort, strip the escort completely out of the equation - and then attack the USSAF with same relative impunity as in summer 1944 through january 1944 (deep Germany).

 

[ctrian]

The P-51 had same or better performance with some individual lesser capability (climb 109, roll 190) while being faster, better range 'as is'. The limitation on the Me 109G and the Fw 190 A5 through A8 was INTERNAL fuel. The drop tanks go at first sighting of e/a - bringing endurance back to very low air time and limited options.

The LW needed high capability long range interception to increase their tactical options, at least in the West.

The P-47D-25 and above could out perform the A8 in nearly every category at bomber altitudes, was more rugged and could carry more stores externally.

The Germans could always place local superiority at the point of attack all the way through Bodenplatte. What they couldn't do from March 1944 forward is defeat the Mustang escort, strip the escort completely out of the equation - and then attack the USSAF with same relative impunity as in summer 1944 through january 1944 (deep Germany).

Same number of aircraft same outcome...

 

[Shortround6]

The crucial point being that both the .50 and 20mm cross the threshold of minimum necessary power.

The Crucial point is that "the threshold of minimum necessary power" changes with both time and aircraft type.

What specific anecdotes are you referring to? Robert Johnson's experience is not anecdotal, it is documented.

Anecdote or documented, a sample of one (or 5 or 10 selected incidents) is too small to reach a conclusion when hundreds of incidents may have occurred.

I am sure "6 20mm shells hit a plane" on many occasions and were not "devastating" to the airframe and did not result in destruction.

While quite true that is not quite what I wrote is it? 6 exploding 20mm shells may be more "devastating" than 12 .5 in punctures. Neither may be enough to bring down an aircraft. To use a single sample of my own there is the incident of a Short Sunderland that was attacked by eight JU-88s, shot down 4 (6?)of them (using mostly .303s ?) and crash landed after the other 4 left (out of ammo, out of fuel, driven off?) with (it is claimed) 500 bullet and shell hits. The only thing this really proves is that with thousands of air to air combats anything is at least possible, almost the entire crew was lost 2 months later when their Sunderland was attacked by Ju-88s.

"Luftwaffe figures that an average pilot hits a 4 engine bomber with 2% of the rounds fired". Would you like to provide the methodology the Luftwaffe used to determine this percentage? Was it the poor quality gun camera images, remaining rounds in returning fighters versus hole counts in downed bombers. I will to bet a beer it was not analysis of only firing passes from head on. "...

I don't know the methodology, The figures are from one of Tony Williams's books. It may have been counting the holes in downed bombers. There was a number for head on passes, while I didn't post the numbers I did say it was a lot fewer in a previous post. The problem(s) with relying on the head on pass are 1. it takes more skill, closing speeds are higher than any other form of attack and give less aiming time and firing time. 2. The Germans developed this attack against B-17Es Fs and early B-24s. which had rather weak nose armament. The head on attack may have diminished in frequency as/after the powered nose turrets were introduced. Maybe somebody with more knowledge of the operational histories can help here?* 3. If the head on attack truly becomes the preferred method increasing the protection at the front of the cockpit is an option.

My position is: Under the conditions of using a single engine fighter to attack U.S. heavy bomber boxes, head on passes with heavy machine guns may have been more effective due to more numerous sufficiently powerful projectiles than the primarily cannon armament of fewer more powerful projectiles that was actually used.
It may also have been a better tactic to use single engine fighters with HMG and larger magazines to attack the escorts so the twin engined fighters with cannons would not be harassed when firing shells out of the effective range of the bombers defending .50s

The Germans certainly had the most experience in trying to shoot down 4 engine bombers. They also were in a position to capture&test a wide variety of aircraft weapons. Not only their own but US, British, Russian and Italian. Which leaves out the Japanese, who are the only other major player. Germans also had access to Swiss and Hungarian guns. Now maybe they did draw the wrong conclusions but several things have to be gotten out of the way for that to be true.
1. what is the weight of the installed armament and ammunition?
Just the weight of 2000rounds of .50 cal ammo is 622lbs. 4 guns worth at 500rpg. While a 190 could carry it it is a bit beyond the ability of a 109. You still need the guns, mounts, heaters, ammo boxes , etc.
going to a less extreme load we find the P-51 could carry a max of 564lbs of ammo and the guns, ammo and armament provisions total around 1200lbs.
More firing time than a 190 for sure but are six .50s really better than 4 20mm MG 151s plus 2 mgs? If the 190 has the MG 131s in cowl the total rounds per second is very close so strikes per second are going to be close. Destructive power is in favor of the German guns (even the 13 mm projectiles have HE or incendiary).
2. As a continuation of the above. what is the effectiveness of the armament vs the weight of the installed armament. The american .50 cal guns were heavy for their caliber and the american .50 cal ammo, while high velocity suffered, as all high velocity rounds do, by being heavy for the size/weight of the projectile.
3. Not only the Germans but the Japanese were moving to bigger guns for destroying bombers. British were standardizing on 4 20mm cannon. Soviets were moving to bigger/more cannon. Was ONLY the USAAF correct in sticking with the machineguns?
And the USAAF was specifying 20mm guns for night fighters (some P-70s and the P-61s) and bomber destroying aircraft. While we may have used six .50s in our fighters in Korea the F-87, F-88, F-89 and F-90 were all specified with 4-6 20mm cannon several years before the fighting broke out in Korea.

 

[Lighthunmust]

This probably comes as a surprise: I agree with you more than disagree. Let me explain.

Shortround6 I would NOT be willing to unequivocally state that P-47s and P51s would be equal to cannon armed German single engine fighters in destroying american style heavy bombers in formation. If I had to place a bet, it would be on the cannon armed fighters. Ctrian my reason for debating this is I believe the effectiveness of German cannons and American M2s has been overstated for years by many sources. The best way to debate this is to take a position challenging accepted belief. The hype around the M2 is only surpassed by that of the .45 ACP M1911 pistol. The belief that the M2 would be greatly less effective or "less than useless" is also overstated. There are many factors other than the terminal ballistics of a projectile that determine a weapons effectiveness. The battle between the bombers and fighters was at that middle point in the endless seesaw of armor versus arm. None of the arms (fighters hindered with projectiles either without devastating power or insufficient quantity) were not overwhelming and the armor (big/strong airframes, and defensive armament with overlapping fields of fire) was vulnerable in many ways. The real massacres of american bombers occurred from not a single attack, but the ability of the Luftwaffe to make repeated attacks on a bomber. Sure one well executed attack could take a bomber down, but I believe this was the exception not the rule, and of course the real killer was large caliber AAA shells exploding into thousands of small projectiles relying on kinetic energy (like bullets). Those long range, partially escorted, bomber missions when the Luftwaffe fighters could land, refuel, and rearm to launch more than one sortie were when they really chewed up the bombers. I hope this debate has brought more balance to the belief of MG<Cannon. Thank you all for the intellectually stimulating debate.

 

[Lighthunmust]

Same number of aircraft same outcome...

I Agree.

 

[Lighthunmust]

The Crucial point is that "the threshold of minimum necessary power" changes with both time and aircraft type.


Anecdote or documented, a sample of one (or 5 or 10 selected incidents) is too small to reach a conclusion when hundreds of incidents may have occurred.


While quite true that is not quite what I wrote is it? 6 exploding 20mm shells may be more "devastating" than 12 .5 in punctures. Neither may be enough to bring down an aircraft. To use a single sample of my own there is the incident of a Short Sunderland that was attacked by eight JU-88s, shot down 4 (6?)of them (using mostly .303s ?) and crash landed after the other 4 left (out of ammo, out of fuel, driven off?) with (it is claimed) 500 bullet and shell hits. The only thing this really proves is that with thousands of air to air combats anything is at least possible, almost the entire crew was lost 2 months later when their Sunderland was attacked by Ju-88s.


I don't know the methodology, The figures are from one of Tony Williams's books. It may have been counting the holes in downed bombers. There was a number for head on passes, while I didn't post the numbers I did say it was a lot fewer in a previous post. The problem(s) with relying on the head on pass are 1. it takes more skill, closing speeds are higher than any other form of attack and give less aiming time and firing time. 2. The Germans developed this attack against B-17Es Fs and early B-24s. which had rather weak nose armament. The head on attack may have diminished in frequency as/after the powered nose turrets were introduced. Maybe somebody with more knowledge of the operational histories can help here?* 3. If the head on attack truly becomes the preferred method increasing the protection at the front of the cockpit is an option.


The Germans certainly had the most experience in trying to shoot down 4 engine bombers. They also were in a position to capture&test a wide variety of aircraft weapons. Not only their own but US, British, Russian and Italian. Which leaves out the Japanese, who are the only other major player. Germans also had access to Swiss and Hungarian guns. Now maybe they did draw the wrong conclusions but several things have to be gotten out of the way for that to be true.
1. what is the weight of the installed armament and ammunition?
Just the weight of 2000rounds of .50 cal ammo is 622lbs. 4 guns worth at 500rpg. While a 190 could carry it it is a bit beyond the ability of a 109. You still need the guns, mounts, heaters, ammo boxes , etc.
going to a less extreme load we find the P-51 could carry a max of 564lbs of ammo and the guns, ammo and armament provisions total around 1200lbs.
More firing time than a 190 for sure but are six .50s really better than 4 20mm MG 151s plus 2 mgs? If the 190 has the MG 131s in cowl the total rounds per second is very close so strikes per second are going to be close. Destructive power is in favor of the German guns (even the 13 mm projectiles have HE or incendiary).
2. As a continuation of the above. what is the effectiveness of the armament vs the weight of the installed armament. The american .50 cal guns were heavy for their caliber and the american .50 cal ammo, while high velocity suffered, as all high velocity rounds do, by being heavy for the size/weight of the projectile.
3. Not only the Germans but the Japanese were moving to bigger guns for destroying bombers. British were standardizing on 4 20mm cannon. Soviets were moving to bigger/more cannon. Was ONLY the USAAF correct in sticking with the machineguns?
And the USAAF was specifying 20mm guns for night fighters (some P-70s and the P-61s) and bomber destroying aircraft. While we may have used six .50s in our fighters in Korea the F-87, F-88, F-89 and F-90 were all specified with 4-6 20mm cannon several years before the fighting broke out in Korea.

Shortround6 I can't adequately express how much I appreciate it when I can get you make the effort to post this kind of response! You contribute so much detail that brings clarity to the topic of discussion.

"The Crucial point is that "the threshold of minimum necessary power" changes with both time and aircraft type." I agree but not a huge change in the short period of time under discussion.

"Anecdote or documented, a sample of one (or 5 or 10 selected incidents) is too small to reach a conclusion when hundreds of incidents may have occurred." True, but there were many more incidents that could be listed if time permitted. My point was to give an example to tone down the exaggerated perception of the devastating power of exploding cannon shells.

"The Germans certainly had the most experience..." Yes they did.

"Now maybe they did draw the wrong conclusions...." Probably not due to their inability to realistically react to the problem in another way.

"Was ONLY the USAAF correct in sticking with the machineguns?" They were only because of the inability to realistically react to the problem in another way.

"Not only the Germans but the Japanese were moving to bigger guns for destroying bombers. British were standardizing on 4 20mm cannon. Soviets were moving to bigger/more cannon." The more things change the more they remain the same. In the post-war decades the U.S. hangs on too long to the 20mm after the rest of the world moves on to 25mm and 30mm.

 

[davebender]

That aircraft and the highly regarded P-51D entered service during the summer of 1944. By then the Me-262 is Germany's only hope to defeat the hordes of Allied bombers.