The original F4F-3 had only 4 x .50 cals with a lot more ammunition per gun than the F4F-4. The change in armament was to suit the British. The GM produced FM version of the F4F-4 reverted back to the 4 x .50 cals of the earlier planes.
- Ivan.
Performance Comparison: Machine Guns and Light Cannon
- Thread starter HoHun
- Start date
The original F4F-3 had only 4 x .50 cals with a lot more ammunition per gun than the F4F-4. The change in armament was to suit the British. The GM produced FM version of the F4F-4 reverted back to the 4 x .50 cals of the earlier planes.
- Ivan.
davebender
1st Lieutenant
That's a function of aircraft size. More airframe to shoot away. But it's not tougher. Any projectile that will harm Me-109 wing will also harm a B-29 wing.
davebender
1st Lieutenant
?
Airframe skin contains no empty space. Any hit will tear up sheet metal (or perhaps wood and fabric). Especially if you are firing explosive shells.
Airframe skin contains no empty space. Any hit will tear up sheet metal (or perhaps wood and fabric). Especially if you are firing explosive shells.
After being banned for being snarky. I will make concerted effort not to be. If anything I write seems to be that was not the intent and I apologize in advance.
My premise is that AP and HE cannot be directly compared. Just because someone converts the units of energy to some pseudo equivalent does not mean that perform the same damage in actual combat.
AP is intended to penetrate a hard target On an aircraft this is the engine (s) and Armor plate (mainly)
HE is intended cause pressure wave to push metal aside until it deforms. The amount of deformation may or may not be considered critical damage.
I simply the concept because in combat it is much more difficult to get an effectiveness measure.
A .50cal hole in a wing was generally considered repairable, not a significant performance degradation. (same for .30). A .50 CAL AP ruins engines and goes through armor plate (to possibly hit the Pilot) with a high probability. You all can quote tables on test better then I on their capabilities.
20mm HE blows holes in AL skin, maybe affecting the performance significantly. But at least American fighters took damage returned to base and even shot down there opponents with damage.
I am not Implying the .50cal was better or worse than the 20mm. I submit the .50cal setup and 20mm setup varied with various results but was acceptable for the limitations and conditions of WWII.
As far as .50cal kills go from what I have seen of the combat footage, engine then pilot (or possibly LOC) then other are the order of the kills. For US vs Japan it seems to be fuel tank, pilot engine, being no around for fuel to pilot this is at least in line with the logic of the situation.
For 20mm frame damage is at least in on the order or the engine pilot fuel tank damage.
I am not proving anything with my statements as I see not data to either corroborate it nor deny it. I offer it for discussion.
As far a heavy opponents vs US, I do not think any valid statements can be made either way as all planes had engines and pilots ( armored) which are the top two kills points of the .50cal Armed US fighters.
OTOH it took alot of 20MM hits on the B-17 in non vitals areas to bring it down. I submit no other plane in the WWII had that sort of ruggedness (P-47,or IL-2 would be closest). So comparing .50cal vs 20mm seems moot when talking about the B-17 as that never happened. It seems to only make sense to talk about common targets. Comments?
My premise is that AP and HE cannot be directly compared. Just because someone converts the units of energy to some pseudo equivalent does not mean that perform the same damage in actual combat.
AP is intended to penetrate a hard target On an aircraft this is the engine (s) and Armor plate (mainly)
HE is intended cause pressure wave to push metal aside until it deforms. The amount of deformation may or may not be considered critical damage.
I simply the concept because in combat it is much more difficult to get an effectiveness measure.
A .50cal hole in a wing was generally considered repairable, not a significant performance degradation. (same for .30). A .50 CAL AP ruins engines and goes through armor plate (to possibly hit the Pilot) with a high probability. You all can quote tables on test better then I on their capabilities.
20mm HE blows holes in AL skin, maybe affecting the performance significantly. But at least American fighters took damage returned to base and even shot down there opponents with damage.
I am not Implying the .50cal was better or worse than the 20mm. I submit the .50cal setup and 20mm setup varied with various results but was acceptable for the limitations and conditions of WWII.
As far as .50cal kills go from what I have seen of the combat footage, engine then pilot (or possibly LOC) then other are the order of the kills. For US vs Japan it seems to be fuel tank, pilot engine, being no around for fuel to pilot this is at least in line with the logic of the situation.
For 20mm frame damage is at least in on the order or the engine pilot fuel tank damage.
I am not proving anything with my statements as I see not data to either corroborate it nor deny it. I offer it for discussion.
As far a heavy opponents vs US, I do not think any valid statements can be made either way as all planes had engines and pilots ( armored) which are the top two kills points of the .50cal Armed US fighters.
OTOH it took alot of 20MM hits on the B-17 in non vitals areas to bring it down. I submit no other plane in the WWII had that sort of ruggedness (P-47,or IL-2 would be closest). So comparing .50cal vs 20mm seems moot when talking about the B-17 as that never happened. It seems to only make sense to talk about common targets. Comments?
Are you saying the B-17 was never fired at with a .50 , so we have no idea how it would stand up to .50 cal. fire ?
The Bf109 from the G5 model and on was on was armed with 2, MG131 guns, 13mm, or .51 cal. .
Isn't that close enough to a .50 cal for you ?
The Bf109 from the G5 model and on was on was armed with 2, MG131 guns, 13mm, or .51 cal. .
Isn't that close enough to a .50 cal for you ?
No the specs on the MG131 were quite different as well as the ammo. Also I find no real references or video which would help us separate 15mm from 20mm in the videos (to compare the 15mm to the .50 cal affects).
Same reason I hesitate from using Russian or Japanese data on their .50 cal. I treat them differently until we prove they are not different.
If you have something I would for one would appreciate it .
Same reason I hesitate from using Russian or Japanese data on their .50 cal. I treat them differently until we prove they are not different.
If you have something I would for one would appreciate it .
davebender
1st Lieutenant
20mm also blows holes in fuel tanks too large to self seal. German night fighter pilots using Schräge Musik weapon (normally a pair of 20mm MG FF cannon) were taught to aim for wing fuel tank. An on target burst was almost always fatal.
Shortround6
Lieutenant General
Your premise is on shaky ground.
True it is just about impossible to compare chemical energy to kinetic, but then people having been trying to equate kinetic energy to damage done for quite a number years and failing. Generally more is better.
The Premise falls apart because NON-EXPLODING projectiles were expected to damage a lot more things than engines and armor plate. Structural damage like spars, longerons, frames, etc will cause the air-frame to fail in flight. Then there is system damage, fuel system, oil system, radios, landing gear, control systems ( cables/rods leading to control surfaces or hinges), etc.
Exploding projectiles were expected to do a whole lot more than just push skin aside. They were expected to destroy many if not all of the same structural members and systems.
The ONLY HE shells to rely on blast alone/primarily were the German Mine shells. EVERYBODY else who used HE shells were depending on both blast AND FRAGMENTS to increase the damage area over and above the diameter of the projectile. This does introduce all sorts of variables into trying to figure out damage but they cannot be ignored or wished away because they are difficult to deal with.
20mm round entered from the far side hit the armor and exploded severely wounding the gunner.
A hit from a non-exploding projectile would have done what?
The .50 cal worked. But it was not as good as most 20mm guns. how much less effective depends on the 20mm ( and there were at least nine different 20mm guns and cartridges in use in WW II) and the ammo used in EACH GUN which often varied by year.
A ground hog and a deer or even a moose are made of the same materials. Are you thinking it is reasonable to hunt them all with the same gun?
I figure the tougher critter is the one that will most likely take more damage before falling down.
- Ivan.
If you wish we can banter back and for with individual pictures of damage. But as with any case someone can always provide a few pics to support a case. I can come back with many pics of P-47's and B-17's with up to multiple 88mm hits and say if an 88mm cant kill it then how can a 20mm?
BDA does not work like that. Unless you assert 1 shot kills and even then kills depends on round effectiveness, number of hits, placement, target ruggedness or type. Not every 20mm round in a fuel tank blew up or was on fire. Not every .50 cal round failed to cause fuel tank to blow up or star a fire eg. Japanese aircraft are the easiest to see that affect.
BDA does not work like that. Unless you assert 1 shot kills and even then kills depends on round effectiveness, number of hits, placement, target ruggedness or type. Not every 20mm round in a fuel tank blew up or was on fire. Not every .50 cal round failed to cause fuel tank to blow up or star a fire eg. Japanese aircraft are the easiest to see that affect.
davebender
1st Lieutenant
I would hazard a guess not more then a couple aircraft survived a direct 88mm or 90mm hit during the entire war. And they survived because the projectile failed to explode and failed to hit anything solid while making an 88mm hole in the fuselage or wing.
Again it was simply to show that individual case can go either way. I am more interested in the big picture of the decisions made a their affect, hence the .50cal setup vs 20mm setup not just round energy (to which it is a part).
Also to make this clear the higher round energy, either chemical or kinetic the better... that's obvious. But for a direct comparison between them there are more factors than round energy that influence the outcome.
Why? He was not insulting anyone in his post.
Shortround6
Lieutenant General
1. I would very much like to see photos of a P-47 that took to multiple 88mm hits.
2. Point of the photos was to show damage you don't seem to think was happening. Control cables on the B-24 were cut by fragments, not blast. A fuselage stringer was cut a number of inches from the point of impact.
On the B-26 damage was done (and crew member wounded) a short distance from the point of impact or from the line of travel of a solid round.
If you refuse to acknowledge certain types of damage that was done by the 20mm rounds it gets very hard to access their damage potential.
Nobody is really claiming one shot kills are they?
B-17 with up to multiple 88 bits. From an old B-17 book I can look some video or pics on the web up and find the same though.
P47 one in the wing huge hole, another case 4 feet of wing gone, that is in Bob Johnson's book.
I am not refusing to acknowledge type of damage for the 20mm, I said is was designed for blast effect and as far as I can tell pre-fragmented warheads in 20mm were not used in WWII or at least very little. Most effort was of larger guns having VT fuzes
Here are a couple links on warhead design. Its to show anyone here how tough it is to design one. Thin or thick cylinders are just at the bottom of the design preference. But they are cheap. They both basically break up into large chunks, not the ideal warhead.
Warheads
Damage Criteria for Fragmentation Warheads
There is a relationship between fragment size, number of fragments, shape, target, velocity, blast pattern.
Too large a fragment and it tends to miss, too small and more fragments tend to hit but do less or insufficient damage.
Overpressure pushes on a surface to bend, yield or break the material. But it drops with 1/R2 (squared). A small firecracker in the open hand tickles, a closed hand gets hurt. It is the not the paper it is the over pressure of an enclosed space it greater than the open.
A time delay on a HE round gets the round inside to expand against the inside skins/structure (confined space). If it hits very closed to a structural element the blast may be high enough to fracture it.
P47 one in the wing huge hole, another case 4 feet of wing gone, that is in Bob Johnson's book.
I am not refusing to acknowledge type of damage for the 20mm, I said is was designed for blast effect and as far as I can tell pre-fragmented warheads in 20mm were not used in WWII or at least very little. Most effort was of larger guns having VT fuzes
Here are a couple links on warhead design. Its to show anyone here how tough it is to design one. Thin or thick cylinders are just at the bottom of the design preference. But they are cheap. They both basically break up into large chunks, not the ideal warhead.
Warheads
Damage Criteria for Fragmentation Warheads
There is a relationship between fragment size, number of fragments, shape, target, velocity, blast pattern.
Too large a fragment and it tends to miss, too small and more fragments tend to hit but do less or insufficient damage.
Overpressure pushes on a surface to bend, yield or break the material. But it drops with 1/R2 (squared). A small firecracker in the open hand tickles, a closed hand gets hurt. It is the not the paper it is the over pressure of an enclosed space it greater than the open.
A time delay on a HE round gets the round inside to expand against the inside skins/structure (confined space). If it hits very closed to a structural element the blast may be high enough to fracture it.
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Glider
Major
Aircraft 20mm shells may or may not have had fragmentation in the design, I simply don't know. But they had the case and that would break up into shrapnel which would have flown around the interior of the aircraft. Those pieces would have the energy to kill or wound the crew, destroy equipment and damage or destroy depending what they hit any structural frames.
So you have the blast which ZJTINS correctly states might if it hits close to a structural element the blast may be high enough to fracture it or damage it. Plus the damage caused by shrapnel.
A 0.50 round which doesn't directly hit something is just going to cause two small holes one going in and one going out.
The photo in posting 30 is a good example. One crew member killed, others wounded and in this case a control wire severed. Looking at the center of the hole an HMG round would have missed the control wire and almost certainly only hit one of the crew.
Photos of any aircraft that came back with massive damage tended to be taken because they were the exception not the rule. Because a P47 came back after a direct hit from an 88mm most certainly doesn't mean that all P47's came back after a direct hit by an 88mm far from it.
I don't have an copy of the book quoted but the description P47 one in the wing huge hole, another case 4 feet of wing gone, that is in Bob Johnson's book. indicates that we are talking about two P47's who each had one hit from an 88 not the previous quote many pics of P-47's and B-17's with up to multiple 88mm hits and say if an 88mm cant kill it then how can a 20mm? which implys one P47 hit many times
As has been pointed out no one is talking about a one shot kill. Its possible of of course, one 20mm hit in the cockpit is likely to kill or wound the pilot and co pilot with the shrapnel destroying the instruments would do the job. Can I prove it, no because they would have crashed and the evidence gone down with the plane.
So you have the blast which ZJTINS correctly states might if it hits close to a structural element the blast may be high enough to fracture it or damage it. Plus the damage caused by shrapnel.
A 0.50 round which doesn't directly hit something is just going to cause two small holes one going in and one going out.
The photo in posting 30 is a good example. One crew member killed, others wounded and in this case a control wire severed. Looking at the center of the hole an HMG round would have missed the control wire and almost certainly only hit one of the crew.
Photos of any aircraft that came back with massive damage tended to be taken because they were the exception not the rule. Because a P47 came back after a direct hit from an 88mm most certainly doesn't mean that all P47's came back after a direct hit by an 88mm far from it.
I don't have an copy of the book quoted but the description P47 one in the wing huge hole, another case 4 feet of wing gone, that is in Bob Johnson's book. indicates that we are talking about two P47's who each had one hit from an 88 not the previous quote many pics of P-47's and B-17's with up to multiple 88mm hits and say if an 88mm cant kill it then how can a 20mm? which implys one P47 hit many times
As has been pointed out no one is talking about a one shot kill. Its possible of of course, one 20mm hit in the cockpit is likely to kill or wound the pilot and co pilot with the shrapnel destroying the instruments would do the job. Can I prove it, no because they would have crashed and the evidence gone down with the plane.
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