Bf109 MG151/15 Variant.

[Les Paul]

Seem to have lost the ability to edit, but I have run across further information about the ammo-belts used.

The first load-out with 4HEI (With Tracers) and 1AP was common for the Western Front 109's, while the 2HEI and 1AP load-out was used on the Eastern Front for obvious reasons.

That Hartkernmunition, because of the limited availability due to supplies, was strictly used for Ground to Ground, or Air to Ground combat. It was essentially banned from use in all Air to Air Sorties.

Also, while I still haven't found out the differences between the Mg151/15E and the Mg151/15, I have learned that the bullets for each were incompatible (The "E" using a special electrical primer.). This is the reason why the outboard cannons on the 190's were also electrically primed, and why the Luftwaffe was hesitant to provide (And eventually abandoned) some Bf109's with a Mg151/20E Gondola mounted on the center-line of the fuselage because the plane's armorers had one hell of a time distinguishing the difference between the two different belts, and if by chance they did manage to mix up the shells, well...Bye bye propellor (Since Synchronization would be thrown off. However the center mounted gun proved very very effective, and had little to no effect on the planes performance.)

Bf109G-4 with center-line, fuselage mounted Mg151/20E Gondola

[Les Paul]

Okay, I hit the holy grail as far as the Mg151 goes, and managed to find an online copy of the Mg151/15 and Mg151/20 manual!

I do not speak fluent German, but I did notice a section devoted to the conversion process between the two (It is more complex than a barrel swap, but from the looks of things still pretty easy to do.)

And while I do in my opinion speak German well, half of these words pertaining to Guns and their parts are completely over my head, and I am not interested in translating a 200+ page German Manual... I was barely able to skim over it as is.

http://stevespages.com/pdf/german_mg151.pdf

[Lusche]

I do not speak fluent German, but I did notice a section devoted to the conversion process between the two (It is more complex than a barrel swap, but from the looks of things still pretty easy to do.)

Actually on page 15 it says:  "The MG 151 becomes a MG 151/20 simply by swapping the 15mm barrel for a 20mm barrel" ("Das MG 151 wird zum MG151/20 lediglich durch Auswechseln des 15-mm-Laufes gegen einen 20-mm-Lauf")

[Les Paul]

Hm, indeed it does say that. Did not know that "Lauf" was also the word for barrel...

Anyway, the guy who gave me the link to the manual said that all it took was a simple barrel swap per say, although because of the design of the weapon, the "Barrel" actually encompassed the breech and some other mechanisms as well that I guess are normally considered separate from the barrel? (In essence it seemed like he was trying to say by swapping the "Barrels" of this gun you actually swapped a few other mechanisms simultaneously, as if they were all part of a singular build that could be removed as a whole and switched out as a whole). Eitherway, he said a skilled armor could swap the two out in about 20 minutes time (Seems a bit time consuming for unthreading a barrel and rethreading a barrel back on...Is that even how its done?)  I don't know nothing about guns. Only that the 15mm one shoots straighter, and penetrates more armor than the 20mm!

Odd how the Allies reports about the two guns clearly states that they are not interchangeable through a simple barrel swap. Perhaps this is what my source was trying to explain to me? And the reason for so much confusion on the subject?

[Lucifer]

Why not the /15, but pl who wants it must remember how unefficient it will be against 1942-1945 planes (not mentionning 95% of bombers) ! 

[Slade]

Bf109G-4 with center-line, fuselage mounted Mg151/20E Gondola

That could be a nice combo. +1

[Les Paul]

Why not the /15, but pl who wants it must remember how unefficient it will be against 1942-1945 planes (not mentionning 95% of bombers) !  

I think it's efficiency will depend on what part of the planes you usually aim for. According to the charts, even the Standard AP munitions have better armor penetration than Hispano 20mms. If you are like me and aim for people cockpits I would argue that Armor Penetration is more important then Explosiveness. However for things like taking of somebodies wing or control surface, explosiveness is much much better. As far as engines go (For bombers), I think its a toss up, with the AP more likely to cause damage, but the more explosive 20mm more likely to make that thing well...Explode.

If they modeled in the Hartkernmunitions, you could probably hit a B17 in the tail, and your bullet would go straight through the cockpit (Okay I lied, it probably wouldn't, but a man can dream!). 48mm at 100 yards, is nearly 2 inches of armor penetration, at 300m you are still getting over 1.5 inches of armor penetration. As far as I know, that will blast through any Pilots Armor Plate and place his brains all over the windscreen, as well as provide a potent and deadly accurate Anti-Tank weapon. At 1,030m/s you are looking at a straighter arc than the American .50 Cals, with nearly double the armor penetration.


There is no doubt in my mind that the Mg151/15 was an absolute beast. The reasons for the Mg151/20 superseding the /15 is most likely because of the reason I stated above, most aircraft wings and control surfaces weren't heavily armored, so having more explosive power would have a much more devastating shot, also coupled with the fact that most WWII pilots most likely had worse aim than most players with 200,000 hours of flight in this game, made the 20mm a better choice.

As the war continued, Allied Armor on planes increased. I have a hunch that back in 1940, and 1941, the /15 variant was prone to over penetration, and it may have actually performed better on the better armored late war bombers.

Another thing to note is that the 109F series does not make use of the 13mm Mg131, it is equipped with the Mg17 which has a muzzle velocity of 900m/s, which is almost perfectly harmonized with the Mg151/15 HE rounds carrying a muzzle velocity of 960m/s. Yes, I understand that the Mg17 is fairly useless, but that near perfect harmonization could have actually given the 15mm cannon a slight edge over its 20mm counterpart. All and all, I think the Germans jumped the gun a bit on abandoning the 15mm for the 20mm.

Just imagine 4 Mg151/15's on a FockeWulf, it would be like having 6-8 American .50 calls at your disposal because the even more accurate (Heavier with equivalent or greater velocity) with twice the armor penetration (Don't know about the HE properties of the American .50cal.. Did they even have HE's?) but it is likely even superior in that aspect as well, not to mention the firing rates of the Mg151/15 and the AN/M2 are nearly on par with one another, the AN/M2 having a slight advantage. Like I said, I think the Germans jumped the gun on their decision to switch over to the Mg151/20.

All in all you are probably right however. The Mg151/20 was probably a better fit for the Bf109 without Rüstsatz modifications, or later war series with the 13mm Mg131 (For Harmonization Purposes). But I think the Mg151/15 would have been a better choice for the multiple cannon configuration seen in the FW190s, or a Gondola equipped 109. But really, I think it would come down to a pilots preference on which gun he liked more, and would still like to see the option available for the 109F, even if it does prove to be inferior to the 151/20

[glzsqd]

American 50cals were generally a mix of AP and incendiary rounds that much I know.

[Motherland]

I think it's efficiency will depend on what part of the planes you usually aim for. According to the charts, even the Standard AP munitions have better armor penetration than Hispano 20mms. If you are like me and aim for people cockpits I would argue that Armor Penetration is more important then Explosiveness. However for things like taking of somebodies wing or control surface, explosiveness is much much better. As far as engines go (For bombers), I think its a toss up, with the AP more likely to cause damage, but the more explosive 20mm more likely to make that thing well...Explode.

If they modeled in the Hartkernmunitions, you could probably hit a B17 in the tail, and your bullet would go straight through the cockpit (Okay I lied, it probably wouldn't, but a man can dream!). 48mm at 100 yards, is nearly 2 inches of armor penetration, at 300m you are still getting over 1.5 inches of armor penetration. As far as I know, that will blast through any Pilots Armor Plate and place his brains all over the windscreen, as well as provide a potent and deadly accurate Anti-Tank weapon. At 1,030m/s you are looking at a straighter arc than the American .50 Cals, with nearly double the armor penetration.


There is no doubt in my mind that the Mg151/15 was an absolute beast. The reasons for the Mg151/20 superseding the /15 is most likely because of the reason I stated above, most aircraft wings and control surfaces weren't heavily armored, so having more explosive power would have a much more devastating shot, also coupled with the fact that most WWII pilots most likely had worse aim than most players with 200,000 hours of flight in this game, made the 20mm a better choice.

As the war continued, Allied Armor on planes increased. I have a hunch that back in 1940, and 1941, the /15 variant was prone to over penetration, and it may have actually performed better on the better armored late war bombers.

Another thing to note is that the 109F series does not make use of the 13mm Mg131, it is equipped with the Mg17 which has a muzzle velocity of 900m/s, which is almost perfectly harmonized with the Mg151/15 HE rounds carrying a muzzle velocity of 960m/s. Yes, I understand that the Mg17 is fairly useless, but that near perfect harmonization could have actually given the 15mm cannon a slight edge over its 20mm counterpart. All and all, I think the Germans jumped the gun a bit on abandoning the 15mm for the 20mm.

Just imagine 4 Mg151/15's on a FockeWulf, it would be like having 6-8 American .50 calls at your disposal because the even more accurate (Heavier with equivalent or greater velocity) with twice the armor penetration (Don't know about the HE properties of the American .50cal.. Did they even have HE's?) but it is likely even superior in that aspect as well, not to mention the firing rates of the Mg151/15 and the AN/M2 are nearly on par with one another, the AN/M2 having a slight advantage. Like I said, I think the Germans jumped the gun on their decision to switch over to the Mg151/20.

All in all you are probably right however. The Mg151/20 was probably a better fit for the Bf109 without Rüstsatz modifications, or later war series with the 13mm Mg131 (For Harmonization Purposes). But I think the Mg151/15 would have been a better choice for the multiple cannon configuration seen in the FW190s, or a Gondola equipped 109. But really, I think it would come down to a pilots preference on which gun he liked more, and would still like to see the option available for the 109F, even if it does prove to be inferior to the 151/20

HTC models ammunition in air-to-air guns by averaging the effects of all of the different rounds. So the 20mm MG151/20 is an average of the penetration/destructive power/ballistics of the HE, AP, incendiary/HEI and tracer rounds for that gun, and the MG151/15 would be the same.
If you're hoping that HTC would model a 109F-2 as firing only a rare type of AP ammunition, let alone any AP ammunition at all exclusively, I'm sorry to disappoint you.
I also don't think that increased penetration abilities would have helped at all punching through the aluminum skin or thin plexiglass cockpit windows of late war bombers. In fact, unless you're hitting, by chance, the 1x5' piece of armor directly behind the cockpit in a fighter, an armor piercing round is doing just about exactly nothing for you. (and even if you are aiming for the cockpit, I can't imagine that that dead six, zero deflection shot presents itself *all* that often, unless you're particularly adept at finding people afk) The accuracy and ballistics of the MG151/15 were valued by some pilots at the time of the switch to the /20 (I think Galland was one of them), but was it a beast? Absolutely not. And there were also pilots who were extremely dissatisfied with the MG151/15's poor firepower coming from the Bf 109E, despite its vastly superior ballistic properties. It was simply much too much underpowered going past.... about the time it was phased out, at the latest.
It would be neat to have the MG151/15 as an option for the F-4 though, there are several F-2 skins for that plane... i did one of them.

[Lucifer]

For what i read in A.Galland book, thats 100% correct, and thats what i meant by "underpowered"...  

And there were also pilots who were extremely dissatisfied with the MG151/15's poor firepower coming from the Bf 109E, despite its vastly superior ballistic properties. It was simply much too much underpowered going past.... about the time it was phased out, at the latest.

[Debrody]

In AH, aircraft armor does not exist, as far as i know. Each part has an amount of hit moint and each round decreases those hit points - if they hit. A part with 0 hp falls off.

Again, as far as i know.

[Les Paul]

In AH, aircraft armor does not exist, as far as i know. Each part has an amount of hit moint and each round decreases those hit points - if they hit. A part with 0 hp falls off.

Again, as far as i know.

Yes, that does seem to be the case. With the current damage modeling, the Mg151/15 would probably be extremely lackluster

 I figured as much with the ammunition since there was no mention of ammo in the hangar. And by no means did I want them to solely make the gun fire the Hartkernmunitions. I entirely agree with you that the penetration capabilities of the shell would be vastly wasted on most aircraft. When I was talking about the effectiveness of AP capabilities, I was trying to elude to the fact that the aircraft's wings, fuselage, and control surfaces often had no armor, were made of cloth, or thin skins of aluminum, however, I do believe that a lot of the bombers had significant armoring around the engines (As well as some fighter/attackers) and to the rear of the cockpit. (Why else do I need to pump 4 or 5 rounds into a B17s engine sometimes to even get it oiled?) And while they weren't always armored, there are structural strong/hard points  (Like the top or bottom keel beam) that can act as some sort of armor against less energetic projectiles

Also, just because no one specific ammunition is modeled, I am sure they could do something that would increase the effectiveness of the Mg151/15 against Ground Vehicles, which do have armor modeled, possibly by adding a multiplier to the weapons damage or something when used against ground targets (Or do whatever they got to do to make it fit their damage model). Other planes have also used the Mg151/15, and it may improve their ground attack capabilities to have that extra armor penetration. I mean, it would be nice if they modeled the Mg151/15 and I could maybe kill a wirblewind with a good burst to the rear, as opposed to just turret'ing or tracking them.

As far as the damage modeling being the way it is, that kinda sucks (Hopefully they will update that soon) I can't tell you how frustrating it is to land a good burst with the 20mm at a pretty shallow angle (Not dead 6 dead 6.) on a F4U's (or any other bird, but mostly this guy because everybody flies them.) aerial mast with a trajectory that would seemingly hit the pilot, or the cockpit in some way or another and they continue on unharmed, I had figured that the reason was because of armor, not because of hit-points, and I now realize this location is probably modeled as something other than the cockpit.

Eitherway, if its a better or worse gun, I would like to see it in game. With maybe an increased effectiveness in the ground attack role in comparison to its Mg151/20 counterpart.

[Karnak]

It would be lackluster with any modeling that was anything like realistic.  It was a lackluster weapon, hence its rapid replacement in service by the Germans.

[Motherland]

On the subject of penetration, do you have any documentation that puts the MG151/15's relevant air-to-air rounds as having a significant advantage in penetration over the MG151/20, let alone any other 20mm autocannon, or are you just making judgments based on muzzle velocity (compare to, for example, the Hispano 20mm, which fired a much, much heavier round at even higher velocities)?

Also, as far as aircraft armor goes, I don't believe that much of it went any further than having a small several-millimeter-thick steel plate in front of particularly-vulnerable components (such as the pilot) from particularly-vulnerable angles. Old 1940s aircraft engines, especially radials, were fairly rugged though.

Having said that, I have to mirror this statement.

It would be lackluster with any modeling that was anything like realistic.  It was a lackluster weapon, hence its rapid replacement in service by the Germans.

[10thmd]

I personally would like to see the mg151/15 in game.