How would you have armed the P38 if you were to use it as it was used historically?

[pinsog]

Back on thread, does anyone here think that 4 concentrated 50's would not be able to do the job against either German or Japanese fighters?

 

[Shortround6]

the problem with 4 concentrated .50's is that they are not laser beams with automatic tracking. If the firing plane is doing 300mph it is doing 440 fps. if the guns are firing at 13rps then the firing plane has moved over 33 ft between consecutive shots from the same barrel. If the target plane is doing 300mph it has also moved 33ft between shots. If either plane is going faster the spacing gets worse. This is assuming that the guns are fastened down to a structure with absolutely no flex whatsoever and ammo and gun have zero dispersion. If you fly a small plane like a 109 at a 90 degree path to the to the 4 gun battery and the 4 gun battery makes no tempt to track the target at speeds in excess of 300mph the 4 gun battery will put a maximum of 4 bullets into the target and a possible minimum of zero hits.
4 concentrated .50's are better than two pairs mounted out in the wings but you still have to keep the target aircraft, not just in the sight but at the proper point in relation to the sight/aiming mark. A lot easier with the later Gyro sights.

The four .50's could do the job. You can also dig a house foundation with hand shovels. There were better tools for both jobs.

 

[Rivet]

"In 1937 just which B-17 equivalent should they have been planning to shoot down?" The only planes I know of during the period were the German Dornier and Junkers heavy developments that were cancelled by Goering's order in April of 1937. Perhaps memories of Italian large Flying Boats crossing the Atlantic, or the three-engined aircraft troubling African targets during the period. Regards

 

[Lighthunmust]

Back on thread, does anyone here think that 4 concentrated 50's would not be able to do the job against either German or Japanese fighters?

I cannot find documentation, but Richard Bong was probably out of 20mm ammunition when he made his first kill. In the engagement he fired at several aircraft, and admitted missing. Bong mentions being in engagements when long bursts were fired when attempting deflection shots. Most of my reading on the subject of bursts fired in WW2 air to air engagements suggests average bursts were 2-3 seconds. Assuming 5-6 seconds being significantly long enough to perceive as a "long burst"; a third of the 20mm ammunition is gone in one burst. Bong commented that he was not a good shot on his first tour. Perhaps a significant number of his victories were achieved with just four .50s firing. One interesting statement I read was that Bong was uncanny in being in the right place to find opponents because many pilots flew many patrols without making contact. I will keep looking for documentation on expenditure of ammunition in combat and better documentation on Bong's and other pilots engagements. I'll look at my book on McGuire next.

Regarding alternate armament for the P-38: As mentioned in a previous post I made, experiments were conducted. Six and Eight gun noses were built. This may or may not be because of dissatisfaction with the 4+1 standard armament. I have found sources of complaint about the U.S. version of the 20mm HS Cannon due to improper manufacture and logistical support requirements. There is a photo in "Aircraft in Profile" V5 of a P-38L with eight .50s in the nose and two twin .50 underwing pods. This version may be intended for ground support, I doubt anyone thought it necessary for air to air.

I would not be surprised to learn that pilots did not refuse to fly with only the .50s operable in a P-38. My personal preference would be for a fifth .50 and all the ammunition space allowed with the removal of the the 20mm ammunition box. Some F4F-4 pilots apparently had enough confidence in four .50s to switched off the outboard a two .50s before engagement. They must of believe they would still be sufficiently effective with two .50s after the four were out of ammunition.

 

[pinsog]

the problem with 4 concentrated .50's is that they are not laser beams with automatic tracking. If the firing plane is doing 300mph it is doing 440 fps. if the guns are firing at 13rps then the firing plane has moved over 33 ft between consecutive shots from the same barrel. If the target plane is doing 300mph it has also moved 33ft between shots. If either plane is going faster the spacing gets worse. This is assuming that the guns are fastened down to a structure with absolutely no flex whatsoever and ammo and gun have zero dispersion. If you fly a small plane like a 109 at a 90 degree path to the to the 4 gun battery and the 4 gun battery makes no tempt to track the target at speeds in excess of 300mph the 4 gun battery will put a maximum of 4 bullets into the target and a possible minimum of zero hits.
4 concentrated .50's are better than two pairs mounted out in the wings but you still have to keep the target aircraft, not just in the sight but at the proper point in relation to the sight/aiming mark. A lot easier with the later Gyro sights.

The four .50's could do the job. You can also dig a house foundation with hand shovels. There were better tools for both jobs.

Everything you just said applies to any weapon, on any fighter, from any side during WW2. Use your same formula but use a B25 with 12 fixed forward firing 50's, you will put a maximum of 12 rounds on target and a minimum of 0. Even M61 Vulcan cannon don't match up well with your formula.

 

[Shortround6]

"In 1937 just which B-17 equivalent should they have been planning to shoot down?" The only planes I know of during the period were the German Dornier and Junkers heavy developments that were cancelled by Goering's order in April of 1937. Perhaps memories of Italian large Flying Boats crossing the Atlantic, or the three-engined aircraft troubling African targets during the period. Regards

The Americans had built the XB-15 bomber and were working on the XB-19 in addition to a couple of preliminary designs and wooden mock-ups to the original specification for a bomber to carry a 2000lb bomb load 5000miles. The Americans probably had a better idea than anybody what size bomber would be needed for intercontinental flights and what type of construction would be needed.

 

[Lighthunmust]

The Americans had built the XB-15 bomber and were working on the XB-19 in addition to a couple of preliminary designs and wooden mock-ups to the original specification for a bomber to carry a 2000lb bomb load 5000miles. The Americans probably had a better idea than anybody what size bomber would be needed for intercontinental flights and what type of construction would be needed.

All thanks to the "Bomber Mafia" that ruled the USAAF. Of course an argument could be made that the "Bomber Mafia" was also one of the worst enemies of the long range heavy bomber.

 

[Jabberwocky]

Just some more information on the reliability of the Hispano. The gun achieved a reliability rate of about one stoppage every 1500 rounds in RAF service by 1943. However, in dusty conditions, such as Africa, Malta and Australia, this could be more than halved. The RAAF found to their horror that their Hispanos were jamming every 90 rounds in 1943 over Darwin. A major part of the problem was that their Spitfires were delivered without heating ducts for the gun bays, while some with the ducts were prone to breaking!

 

[Lighthunmust]

Just some more information on the reliability of the Hispano. The gun achieved a reliability rate of about one stoppage every 1500 rounds in RAF service by 1943. However, in dusty conditions, such as Africa, Malta and Australia, this could be more than halved. The RAAF found to their horror that their Hispanos were jamming every 90 rounds in 1943 over Darwin. A major part of the problem was that their Spitfires were delivered without heating ducts for the gun bays, while some with the ducts were prone to breaking!

The redundancy of a greater number of HMG has some advantages. Not that it can't also have issues with installation, but the M2 has a reputation of reliability that few other automatic weapons can match.

 

[Jabberwocky]

That reputation was not undeserved, but reliability could vary by more than a factor of three, depending on the aircraft and installation.

Nose installations were generally the most reliable. Wing installations less so, notably in the P-51 B/C, but the RAAF also had problems with stoppages in their Beaufighters. Both problems are best attributed to the feed arrangement, rather than the weapon itself.

Spitfire Mk VCs also traced much of their cannon problems to the belt mechanism, a problem not suffered with the earlier snail magazine. Changes to the mechanism, then - somewhat ironically, given the US reliability problems with the Hispano - switching to a US developed belt feeding mechanism improved reliability.

 

[fastmongrel]

Spitfire Mk VCs also traced much of their cannon problems to the belt mechanism, a problem not suffered with the earlier snail magazine. Changes to the mechanism, then - somewhat ironically, given the US reliability problems with the Hispano - switching to a US developed belt feeding mechanism improved reliability.

The Spitfire VC had a Martin Baker belt feed mechanism. Martin Baker is a British company.

 

[Shortround6]

We are trying to come up with the reliability of two weapons that were not only installed in a variety of aircraft in a number of different ways but also, in the case of the Hispano, used different feed mechanisms and was made to different standards in the two major countries that used it.
The Browning .50, while it obviously is a classic that has endured for many, many years was also made for quite a number of years and was used in a number of ways, not all combinations exhibit the same reliability.

As for the Hispano, it needed a rigid mounting, not always easy to achieve in wings compared to fuselage mounts. It did not take kindly to being turned 90 degrees on it's side with it's drum in early Spitfire installations. Both experimental MK I and early MK Vs. It didn't tolerate cold as well as the Browning and yes it needed more (better) maintenance. Things did get better as the war went on, as experience mounted, both maintenance and installation knowledge built up. This for British guns, the American insistence on excessive head space in the chamber specifications doomed the American guns to a history of trouble.

However the same can be said of the Browning, What is a reliable gun on a test stand at sea level in relatively warm weather (even 0 degrees beats -40) may not be so reliable at 25,000ft in a 3 "G" turn. What is a reliable gun chugging away at 450-550rpm on a ground mount may not be so reliable trying to do 800-850rpm pulling that heavy belt from a number of feet away.
A lot of the early installations of the Browning gave trouble and were less than satisfactory. Again, as time went on and experience was gained the situation improved.
The Browning probably always had an edge in average reliability in aircraft use. The amount of this margin or edge may have changed with both time and specific installations.

 

[Rivet]

I'm partial to the work of those folks from Utah, myself. The M2 .50 Caliber Recoil Operated Machine Gun would have been my choice for primary armament for the P-38, four of em, mounted as tight to the centerline as would be possible.

Little Story:
John Moses Browning was on the range early in Aberdeen, Maryland the day World War I ended. With him, in answer to a military contract, he had his prototype of his requested .50 Caliber fully automatic rifle. Having no purpose built mount for the weapon Browning used a .30 Caliber tripod. Browning set up the gun on the range, sat behind it, opened the breech and poured the contents of a paper bag he produced from his jacket pocket into it. When questioned as to the contents of the bag by accompanying ordnance officers he replied, "Sand. If it does not take this what good is it?" A ten round belt of newly made cartridges was loaded. The weapon functioned through the ten round burst, Browning getting a jack-rabbit ride on the light mount.

"The Browning probably always had an edge in average reliability in aircraft use. The amount of this margin or edge may have changed with both time and specific installations. "

Material specifications changes.


I'd seen a few posts in here decrying the terminal effectiveness of the .50 Cal. M-2 vs. 20mm. Friend, I am fair confident that the 750 grain pill delivered by the M-2 is capable of taking apart most anything put in its way, with the benefit of being able to carry more of them than the larger rounds.
Regards

 

[Lighthunmust]

I'm partial to the work of those folks from Utah, myself. The M2 .50 Caliber Recoil Operated Machine Gun would have been my choice for primary armament for the P-38, four of em, mounted as tight to the centerline as would be possible.

Little Story:
John Moses Browning was on the range early in Aberdeen, Maryland the day World War I ended. With him, in answer to a military contract, he had his prototype of his requested .50 Caliber fully automatic rifle. Having no purpose built mount for the weapon Browning used a .30 Caliber tripod. Browning set up the gun on the range, sat behind it, opened the breech and poured the contents of a paper bag he produced from his jacket pocket into it. When questioned as to the contents of the bag by accompanying ordnance officers he replied, "Sand. If it does not take this what good is it?" A ten round belt of newly made cartridges was loaded. The weapon functioned through the ten round burst, Browning getting a jack-rabbit ride on the light mount.

"The Browning probably always had an edge in average reliability in aircraft use. The amount of this margin or edge may have changed with both time and specific installations. "

Material specifications changes.


I'd seen a few posts in here decrying the terminal effectiveness of the .50 Cal. M-2 vs. 20mm. Friend, I am fair confident that the 750 grain pill delivered by the M-2 is capable of taking apart most anything put in its way, with the benefit of being able to carry more of them than the larger rounds.
Regards

I'm partial to the work of those folks from Utah, myself. The M2 .50 Caliber Recoil Operated Machine Gun would have been my choice for primary armament for the P-38, four of em, mounted as tight to the centerline as would be possible.

Little Story:
John Moses Browning was on the range early in Aberdeen, Maryland the day World War I ended. With him, in answer to a military contract, he had his prototype of his requested .50 Caliber fully automatic rifle. Having no purpose built mount for the weapon Browning used a .30 Caliber tripod. Browning set up the gun on the range, sat behind it, opened the breech and poured the contents of a paper bag he produced from his jacket pocket into it. When questioned as to the contents of the bag by accompanying ordnance officers he replied, "Sand. If it does not take this what good is it?" A ten round belt of newly made cartridges was loaded. The weapon functioned through the ten round burst, Browning getting a jack-rabbit ride on the light mount.

"The Browning probably always had an edge in average reliability in aircraft use. The amount of this margin or edge may have changed with both time and specific installations. "

Material specifications changes.


I'd seen a few posts in here decrying the terminal effectiveness of the .50 Cal. M-2 vs. 20mm. Friend, I am fair confident that the 750 grain pill delivered by the M-2 is capable of taking apart most anything put in its way, with the benefit of being able to carry more of them than the larger rounds.
Regards

Rivet,

I have not been a member of this forum for even a month. From what I have read you and I seem to be in the minority regarding the effectiveness of the M2 for WW2 aerial combat. No doubt the cannon has the edge in individual projectile power, but there are many other factors involved. I am researching just how much the MG<Cannon gap really was. So far I believe it looks large in tables and graphs of projectile power and individual weapon cyclic rates, and not so much in actual use. Part of the problem is we don't have many reports of 6/8 gun American fighters attempting to shoot down strongly build, heavily armed, four engined bombers. I wonder why? What I am finding is German accounts of shooting down bombers in one firing pass being atypical. It taking multiple firing passes to force bombers out of formation and then finishing them off. I am finding accounts of the Germans believing hits from twenty 20mm shells or three 30mm shells being necessary to destroy a heavy bomber. I also find accounts of Germans having a 2-4% hit percentage. Sources claim that some of the German cannons equal the cyclic rates of the M2. One of these source usually lists a single rate for the cannons, but a slow and fast rate for the M2. This makes we wonder about a level playing field of primary sources and testing. I am still working on determining what the balance point is between weapons with smaller amounts of devastating projectile power and weapons with larger amounts of sufficient projectile power. To the best of my knowledge, no one has address the actual firing reliabilty of the German cannons or the engagement times of single engine fighters attacking the bombers. I don't consider those over loaded FW190s fighters, they were bomber destroyers and sitting ducks for true fighters. Consider this; would the P-38 mock-up with 12 .50s been an even better bomber destroyer than the cannon armed FW190? It also would cease to be a fighter and become a sitting duck. I have actually fired and M2s and a Dshk, and seen upclose the what hits from .50s and 20mms do to lightly armored targets. The .50s destroyed the targets ability to function, the 20mms destroyed the target. The 20mms did it from the altitude of an AC-130, the .50s from 1000 yards. Either results in a kill if the targets were flying at 20,000 feet. WW2 aerial air to air engagements were rarely more than half of a 1000yards.

Of course installation and environment affected M2 functioning, but I suspect that all those wonderful cannons were much more adversely affected as were the aircraft that mounted them. Here is an example: It is my understanding that on one of the late mark Spitfires they had to remove two of the four 20mms and replace them with .50s because of aircraft flight handling issues. I'm sure shortround6 can find the details faster than I can. He has an amazing ability to post detailed specifications and dates of events. I am wondering about him being a professional aviation writer or some kind of aviation savant. I suspect he has a very good idea of what a .50cal projectile can do.

 

[tomo pauk]

The 'pill' from .50cal can surely kill - providing it can hit the thing that can be killed. 3 or 4 dozens of rounds piercing wing skin don't kill, they just pierce the skin. Compare that with one or two dozens of cannon shells hitting the wing - each shell makes a neat hole (foot or two in diameter, depending on size construction of shell).

 

[Lighthunmust]

The 'pill' from .50cal can surely kill - providing it can hit the thing that can be killed. 3 or 4 dozens of rounds piercing wing skin don't kill, they just pierce the skin. Compare that with one or two dozens of cannon shells hitting the wing - each shell makes a neat hole (foot or two in diameter, depending on size construction of shell).

No one disputes this. But what you wrote is far from a complete answer to the question of actual effectiveness in WW2. 1 or 2 dozens of cannon shells? How many firing passes at 2-4% hit rates does that require from a single engine fighter. One .50cal bullet can kill an engine, or reduce its power enough to impede the bombers ability to remain in formation.

 

[tomo pauk]

1 or 2 dozens of cannon shells? How many firing passes at 2-4% hit rates does that require from a single engine fighter.

How many passes would've required 3-4 dozens of .50cal ammo?

One .50cal bullet can kill an engine, or reduce its power enough to impede the bombers ability to remain in formation.

The air force that was under hell of a pressure to stop a major bomber offensive concluded that smaller number of cannons were better bet than large number of HMGs. I tend to agree with them.

 

[Lighthunmust]

How many passes would've required 3-4 dozens of .50cal ammo?



The air force that was under hell of a pressure to stop a major bomber offensive concluded that smaller number of cannons were better bet than large number of HMGs. I tend to agree with them.

It is your assumption that 3-4 dozens of .50cal ammo would be needed. It would take me a great amount of time to calculate number of firing passes due to different armament packages on different fighters.

Even if the Luftwaffe had decided the other way, they probably had no real choice but to go with the cannons. Resource availability and aircraft platform armament flexibility are factors to consider. Do we really know if an aircraft armament package of HMG could not be designed where all factors of firepower would be as or more effective than a cannon package for the fighters of WW2?

 

[Rivet]

"How many passes would've required 3-4 dozens of .50cal ammo?"

You'd have 6.1 seconds of firing time to expend the low end of 36 rounds (3 Dozen) from one M-2 Browning set to fire at 400 r.p.m. Regards

 

[tomo pauk]

It is your assumption that 3-4 dozens of .50cal ammo would be needed. It would take me a great amount of time to calculate number of firing passes due to different armament packages on different fighters.

We can assume what we want. Assuming that it would've taken less hits by a projectile of far lower destruction power is not something I'd agree, however. Hence my 3-4 dozens of .50 cal ammo assumption.
If you want to calculate stuff, perhaps 5 x .50cals for Bf-109Gs and 6 .50cals for Fw-190 might be a good starting point. 2 HMGs synchronized for 109, 4 for 190.

Even if the Luftwaffe had decided the other way, they probably had no real choice but to go with the cannons. Resource availability and aircraft platform armament flexibility are factors to consider. Do we really know if an aircraft armament package of HMG could not be designed where all factors of firepower would be as or more effective than a cannon package for the fighters of WW2?

You'll have to dig further about that.
For real air forces, RAF, VVS, LW, IJA/IJN, RA (even USN) went for 20mm (and/or above) as WW2 dragged towards end, while USAAC remained mostly with HMG. so I'd conclude that cannon was seen as a more viable weapon.