Bf-109 13mm belt composition

[oc2209]

As the title says, what's the mix of AP and HE in a 13mm belt? Specifically in a 109G-6 Late, for the example I'm about to use.

 

I'm wondering how things like this happen (with regularity):

 

 

By my count, it's 28 HE strikes (red circles) to 8 AP strikes (yellow circles). It was all from the same burst, not cumulative from several attacks.

 

The reason I'm interested is that I find it annoying when I'm trying to kill pilots and all my hits to their armored backrest happen to be HE with no penetration.

 

For example, there are many instances like this:

 

 

Where a pilot survives (and isn't even knocked unconscious temporarily) the cockpit area being blanketed with 13mm HE hits, while a single penetrating AP hit to the backrest is all I really need.

 

The AP striking the backrest makes a distinct puff that I've observed and differentiated from HE strikes by recording AP-only and HE-only attacks from La-5s.

 

Here's the visual difference:

 

 

Red circle is an HE impact, yellow is an AP. When AP strikes the regular part of the airplane (the skin), it makes a spark; not a dull puff. That's how a headrest/backrest AP impact is discernible. The pilot died from this attack. Of course there's no way for me to determine if the AP or HE killed him, but I would bet very good money that the AP did the most damage to the pilot. In terms of penetration probabilities, the distances involved are negligible; 100m or less in the above screens.

 

Also, this thread is not a complaint. I'm just wondering about the belt ratios. If I'm unlucky by not getting an AP hit when I need one, that's my problem. I'd only like to figure out the odds involved.

[-=PHX=-SuperEtendard]

13mm belt composition is 66% HE, 33% AP

[oc2209]

Just now, -=PHX=-SuperEtendard said:

13mm belt composition is 66% HE, 33% AP

 

That more or less fits with what I've seen, then.

 

Thanks for the quick reply!

[Yogiflight]

17 minutes ago, oc2209 said:

By my count, it's 28 HE strikes (red circles) to 8 AP strikes (yellow circles). It was all from the same burst, not cumulative from several attacks.

I wouldn't give too much on the holes, though. In your next try you will most likely see exactly the same holes. It is just a damage layer copied on the surface.

[Mtnbiker1998]

1 hour ago, Yogiflight said:

I wouldn't give too much on the holes, though. In your next try you will most likely see exactly the same holes. It is just a damage layer copied on the surface.

Wrong. The P-51 as shown has the new DVD effects. They are easily distinguishable from the old baked in damage visuals. 

[Jaws2002]

There's something not very right with that first image. High explosive 13mm rounds should make much bigger holes in the surface of the wing. Maybe the visual damage model is not reflecting the actual damage, but after 28 HE hits on that wing, there should be very little skin left in that area of the wing.

 

 Reports of the Belgian built 13.2x99mm, high explosive rounds, for the FN version of the Browning machine gun,  mentions 60cm exit holes.

Maybe that is the entrance side....

 

 

 

[oc2209]

1 hour ago, Mtnbiker1998 said:

Wrong. The P-51 as shown has the new DVD effects. They are easily distinguishable from the old baked in damage visuals. 

 

Yup. It's been around for quite a while now, but I guess some people haven't looked closely at it.

 

I admit I'm rather obsessive about it.

 

Here's a very clear side-by-side for those who aren't.

 

Old damage visuals:

 

 

New DVD decals (circled) along with old damage visuals:

 

 

If you're wondering how I 'erased' the DVD for the first screenshot, it happens during replays. If you watch a track from start to finish without jumping back and forth, it shows all the DVD hits as you made them during the sortie. If you jump to one part of the track (like skipping from the start to the 90 second mark), it tends to omit many, sometimes all, of the DVD decals. The old damage visuals always show up regardless. 

[oc2209]

Here's one more example of DVD. 30mm HE decals make the comparisons much easier than smaller calibers. I'm not even going to bother circling it because it's so obvious.

 

 

The DVD decal noticeably catches light sources around its edges, while the old damage visuals do not react to lighting at all. The old visuals also have no illusion of depth. They look like burnt paper on a flat surface. DVD has a much better metallic effect.

 

The smaller caliber decals show light and texture similarly to the above example, but are of course smaller and harder to notice for the untrained eye.

 

2 hours ago, Jaws2002 said:

Maybe the visual damage model is not reflecting the actual damage, but after 28 HE hits on that wing, there should be very little skin left in that area of the wing.

 

No, the visual model can't strip the skin away and show us the framework. It'd be great if it could, but we can live without it.

 

Functionally, the wing was destroyed. The aileron control was totally gone (evident during the replay), and the plane rolled over on its side and immediately crashed. Even if the aileron was still functional, the lift properties of the wing would be so degraded that even AI couldn't keep it straight.

 

What surprised me more was how the fuel in that wing didn't catch fire. Typically once a fuel leak begins, it's much easier to start a fire with subsequent shots in the same area.

 

I normally wouldn't waste so many shots on a wing, but I wanted a flat surface to make counting AP/HE holes easier. The AI obliged me by providing a broad deflection target in a sustained turn.

Edited November 15, 2021 by oc2209

[-=PHX=-SuperEtendard]

4 hours ago, Jaws2002 said:

There's something not very right with that first image. High explosive 13mm rounds should make much bigger holes in the surface of the wing. Maybe the visual damage model is not reflecting the actual damage, but after 28 HE hits on that wing, there should be very little skin left in that area of the wing.

 

 Reports of the Belgian built 13.2x99mm, high explosive rounds, for the FN version of the Browning machine gun,  mentions 60cm exit holes.

Maybe that is the entrance side....

The game only has entrance holes for it's dynamic decal model and from what we know also only entrance holes are considered for the aero DM. Also from what I could translate that 60cm figure would be for a fabric covered wing surface, which would be more vulnerable against a high explosive blast/fragmentation. You would expect 60cm holes out of a high caliber cannon hit against a duralumin wing.

For example, from an old post by Hiromachi, the 12.7mm Berezin MDZ-46 HEI round when fired against a duralumin wing, created an entry hole of 2cm and an exit hole of 11cm in diameter.

The VYa-23 HE round caused a 26cm entry hole and a 50cm diameter exit hole.

Edited November 15, 2021 by -=PHX=-SuperEtendard

[Voidhunger]

9 hours ago, Mtnbiker1998 said:

Wrong. The P-51 as shown has the new DVD effects. They are easily distinguishable from the old baked in damage visuals. 

Yes, but its not showing all the damage. Its just looks better.

[JG4_Widukind]

Lately (TAWE) I see that we are getting more and more headshots with the late planes, especially with Hispano cannons. (Spit and Tempest) Mostly it's the shock effect (black screen with small viewing area) But also immediately outside view. (Death) The question is is it the same with the allies (I mostly fly Focke) Do we have too high a modeling of Hispanics? Is the pilot's damage (head and body set too high?

 

 

[Cpt_Siddy]

 

[Denum]

Grabs bingo card.

[HR_Zunzun]

7 hours ago, JG4_Widukind said:

Lately (TAWE) I see that we are getting more and more headshots with the late planes, especially with Hispano cannons. (Spit and Tempest) Mostly it's the shock effect (black screen with small viewing area) But also immediately outside view. (Death) The question is is it the same with the allies (I mostly fly Focke) Do we have too high a modeling of Hispanics? Is the pilot's damage (head and body set too high?

 

 

 

I do not known what you mean by pilot´s damage. One 50cal direct hit to almost any part of human anatomy is medically catastrophic. 20mm is much worse.

I would dare to say that 90% of the time you are directly hit you should be toasted (aka "immediately outside view").

The 20mm indirect hit (shrapnel effect) could be disputable and subjected to different circumstances (distance etc...).

Another matter is how the sim calculate when there is a direct hit or (for the 20mm) an indirect hit (shrapnel).

[ShamrockOneFive]

6 hours ago, Cpt_Siddy said:

 

 

That is absolutely fascinating. I love data visualizations!

 

60mm across is actually not as big as I would have expected. But still, obviously, substantial especially if hit with a few of them.

[oc2209]

8 hours ago, JG4_Widukind said:

Do we have too high a modeling of Hispanics? Is the pilot's damage (head and body set too high?

 

Short answer: no.

 

Longer answer: hell no.

 

Seriously, this isn't like the old westerns where the hero gets their skull 'creased' by a glancing shot, or a minor 'in and out' flesh wound in their arm or flank. 20mm doesn't 'wing' a person, any more than being hit by a sledgehammer would give you a light bruise. It's a simple matter of mass and energy.

[the_emperor]

 

Quote

 

That is absolutely fascinating. I love data visualizations!

 

60mm across is actually not as big as I would have expected. But still, obviously, substantial especially if hit with a few of them.

 

Yes that visual simulation is indeed facinating. What is missing though is the delay for the mineshell (20-75cm). that going of inside the wing structure would probably be a bit more damaging since the explosion does take place in a confined space and the air craft skin/wing structure itself is under stress and you will have a hole on both sides of the wing

 

Here is one (probably) 20mm mineshell hit to the right horizontal stabilizer of a B-17 (less stressed than a fighter wing).

8 hours ago, JG4_Widukind said:

Do we have too high a modeling of Hispanics?

No; the Hispano fires a 0.29lb slug at 2730 feet/s (131.5g at 835m/s). Nothing in your plane will be able to stop that round in any significant way. 

Edited November 15, 2021 by the_emperor

[oc2209]

12 minutes ago, the_emperor said:

Here is one (probably) 20mm mineshell hit to the right horizontal stabilizer of a B-17 (less stressed that a fighter wing).

 

Are you 100% sure that's not a 30mm hit? Looks like a 30mm to me. Between the size of the flash and the subsequent hole and skin shredding effect.

[the_emperor]

20 minutes ago, oc2209 said:

Are you 100% sure that's not a 30mm hit? Looks like a 30mm to me. Between the size of the flash and the subsequent hole and skin shredding effect.

No, not a 100% but the film says it is a Focke Wulf A8 and from the hits and gunfire before it looks more like 20mm than 30mm, especially compared to the extensive and detailed british test of the 30mm. Granted in the still and enhanced the flash looks bigger than in the film. Here is the video (starts at the the quotet sequence):

 

 

here is another more detailes sequenze of (probably) 20mm vs the horizontal stabilizer of a B-17:

 

Edited November 15, 2021 by the_emperor

[oc2209]

1 hour ago, the_emperor said:

No, not a 100% but the film says it is a Focke Wulf A8 and from the hits and gunfire before it looks more like 20mm than 30mm, especially compared to the extensive and detailed british test of the 30mm. Granted in the still and enhanced the flash looks bigger than in the film.

 

Hard to be sure. Technically the A-8 could be firing a mix of 20mm and 30mm, which might explain some flashes being bigger than others. One time I saw a huge piece of skin/wing fly back toward the camera (in a different part of the video), which I think only a 30mm would do.

 

The B-17 was a tough bastard, and it wouldn't surprise me at all to see a horizontal stabilizer survive a direct 30mm hit without breaking up. The only place a 30mm hit is going to be an almost guaranteed kill (on a 4-engine bomber, and not counting the obvious--a cockpit hit) is the wing roots or mid-wing, and only then if it lights up the nearby fuel tanks.

 

In terms of structurally tearing a B-17 apart, I would imagine that takes several 30mm hits in the same location.

 

10 hours ago, JG4_Widukind said:

Lately (TAWE) I see that we are getting more and more headshots with the late planes, especially with Hispano cannons. (Spit and Tempest) Mostly it's the shock effect (black screen with small viewing area) But also immediately outside view. (Death) The question is is it the same with the allies (I mostly fly Focke)

 

Here, these two clips I just made should allay your concerns:

 

109G-6 Late firing 20mm versus a P-51:

 

Spoiler

 

 

It is my pseudo professional opinion that an AP hit to the backrest armor killed him in the above example.

 

In the following example, I believe HE killed him (the AP puff occurred well after he entered the killed/unconscious animation):

 

Spoiler

 

 

Point being, accurate 20mm fire into the cockpit area will reliably kill pilots. Be it Axis or Allied munitions.

Edited November 15, 2021 by oc2209

[Eisenfaustus]

11 hours ago, oc2209 said:

Point being, accurate 20mm fire into the cockpit area will reliably kill pilots. Be it Axis or Allied munitions.

I know what you mean - yet armor will protect against most he rounds. Without his headrest armor Adolf Galland would have died from a British 20mm he-round according to his memoirs. 

[the_emperor]

11 hours ago, oc2209 said:

Hard to be sure. Technically the A-8 could be firing a mix of 20mm and 30mm, which might explain some flashes being bigger than others. One time I saw a huge piece of skin/wing fly back toward the camera (in a different part of the video), which I think only a 30mm would do.

Yes of course, one cant be 100% sure and its a little bit of guessing andspeculation. But the probability that we see here A8s armed with the standard 4 x 20mm cannon is higher. I would also say, that this hit in particular is the "perfect" mineshell hit (hit angle, delay), where everything comes togehter for the "best outcome".

[Jaws2002]

3 hours ago, the_emperor said:

I would also say, that this hit in particular is the "perfect" mineshell hit (hit angle, delay), where everything comes togehter for the "best outcome".

 

I'd say it's typical mineshell hitting a narrow confined space, where the pressure wave has no room to dissipate.

 Hits to fuselage of heavy bombers were not as damaging as hits to wings and tail, because a lot of the pressure is lost in the large volume of the fuselage.

 

[the_emperor]

1 hour ago, Jaws2002 said:

I'd say it's typical mineshell hitting a narrow confined space, where the pressure wave has no room to dissipate.

yes, that if course contributes to the "perfect" hit. All parameters letting the mineshell working as it is intended ?   

and "fortunately" this sequence gives us a detailed look of such  single hit.

Edited November 16, 2021 by the_emperor

[Barnacles]

Just some really rough and ready comparison with the size of the known 108 detonation on the spitfire wing and the hit on the b17 from that guncam.

Recognising that 

1. It's very rough, those wing lengths are not exact but are ok for a rough comparison (B17 total tail span is 43feet and spit wingspan is 36.9feet)
2. The film is not very high quality, but I did my best to identify the lobes of the incandescent part of the explosion. I've no idea how these would be affected by the airspeed (prob not much as it is small compared to the velocity of the explosive gases), construction of the wing or proximity to ground (maybe the spitfire lobe would extend further were it not for the ground, but it may be shorter because of exactly where the round detonated, ie the top of the wing)
3. I'm literally just counting pixels so it's not very accurate, also the frame rate of the camera might have missed the gas ball at its brightest etc.

However, you can see that they are roughly the same order of size, so I conclude the guncam can't exclude the possibility that this is a 108 hit on the b17, and if all the errors/estimates average out I'd say it looks like it probably is a 108 hit as far as we can tell. However, I don't have any images of a certain 151/20 hit either, so it'd be interesting to compare those if anyone has any. Especially as the spit II explosion might be larger if the ground hadn't have been there.

 

 

 

 

Edited November 16, 2021 by Barnacles

[the_emperor]

i would never exclude the probability of a 30mm hit. i would just say the probability of a 20mm shell is higher. for the 30mm spit wing hit shouldnt it be double the size of blast of the top of the wing, since the bottom is blocked by the ground?

[Barnacles]

8 minutes ago, the_emperor said:

i would never exclude the probability of a 30mm hit. i would just say the probability of a 20mm shell is higher. for the 30mm spit wing hit shouldnt it be double the size of blast of the top of the wing, since the bottom is blocked by the ground?

Maybe, but in the B17 shot the top lobe is much shorter than the bottom lobe. Clearly that's because of where they hit, but if we're going to take the largest lobe then double, the two explosions are very similar in size.

 

Edited November 16, 2021 by Barnacles

[Jaws2002]

20 minutes ago, Barnacles said:

Just some really rough and ready comparison with the size of the known 108 detonation on the spitfire wing and the hit on the b17 from that guncam.

Recognising that 

1. It's very rough, those wing lengths are not exact but are ok for a rough comparison (B17 total tail span is 43feet and spit wingspan is 36.9feet)
2. The film is not very high quality, but I did my best to identify the lobes of the incandescent part of the explosion. I've no idea how these would be affected by the airspeed (prob not much as it is small compared to the velocity of the explosive gases), construction of the wing or proximity to ground (maybe the spitfire lobe would extend further were it not for the ground, but it may be shorter because of exactly where the round detonated, ie the top of the wing)
3. I'm literally just counting pixels so it's not very accurate, also the frame rate of the camera might have missed the gas ball at its brightest etc.

However, you can see that they are roughly the same order of size, so I conclude the guncam can't exclude the possibility that this is a 108 hit on the b17, and if all the errors/estimates average out I'd say it looks like it probably is a 108 hit as far as we can tell. However, I don't have any images of a certain 151/20 hit either, so it'd be interesting to compare those if anyone has any. Especially as the spit II explosion might be larger if the ground hadn't have been there.

 

 

I think that image captured two simultaneous hits, one in the tail and one in the end of the engine nacelle. Just look at the images after that one. You see debris coming out of both, the tail and the wing. So maybe we have two 5-6 feet flashes, instead of a 10 feet blast.

Edited November 16, 2021 by Jaws2002

[Barnacles]

Here's another one which probably doesn't add anything conclusive as this explosion was confined in a much different way to the b17 hit, but interesting anyway.

[Voidhunger]

This is only confirmed video footage of Mk108 (from the Me163B) in action and this B17 returned from the mission.

 

 

Edited November 16, 2021 by Voidhunger

[=621=Samikatz]

These old cameras are quite prone to distortion and artifacts, especially from large flashes of light, I would not try to measure the size of an explosion from them

[Barnacles]

12 minutes ago, Jaws2002 said:

 

 

I think that image captured two simultaneous hits, one in the tail and one in the end of the engine nacelle. Just look at the images after that one. You see debris coming out of both, the tail and the wing. So maybe we have two 5-6 feet flashes, instead of a 10 feet blast.

Looking at it again, I disagree with that, if you look frame by frame the incandescent part cools to smoke, and you can see the cloud move backward together in the airstream making it look to me like that was definitely one explosion, on the stbd. stabiliser.

1 minute ago, Voidhunger said:

This is only confirmed video footage of Mk108 (from the ME163B) in action and this B17 returned from the mission.

 

 

Are there any photos of the returned b17?

 

[Voidhunger]

10 minutes ago, Barnacles said:

Looking at it again, I disagree with that, if you look frame by frame the incandescent part cools to smoke, and you can see the cloud move backward together in the airstream making it look to me like that was definitely one explosion, on the stbd. stabiliser.

Are there any photos of the returned b17?

 

 

 

[Barnacles]

29 minutes ago, =621=Samikatz said:

These old cameras are quite prone to distortion and artifacts, especially from large flashes of light, I would not try to measure the size of an explosion from them

From that film, do you think that that camera was suffering from distortion such as would materially affect what I was trying to demonstrate? Which I said several times was a very rough estimate. 

 

17 minutes ago, Voidhunger said:

 

 

Oof

Edited November 16, 2021 by Barnacles

[Voidhunger]

[the_emperor]

for reverence I would urge to have a look the film sequences  I took the screenshots from. they look more dramatic than in the film itself. The B-17 also get multiple hits in the left stabilizer before the single hit in the right one.

I also inlcuded another sequence of hitsto the tail of another B-17. To me (and that is purely sbujectiv) that looks more like 20mm hits than 30mm hits:

 

 

Edited November 16, 2021 by the_emperor

[oc2209]

17 hours ago, Eisenfaustus said:

I know what you mean - yet armor will protect against most he rounds.

 

Of course. HE's shrapnel dispersion is erratic and therefore unreliable; and even armored glass is seemingly proof against shrapnel.

 

That's why I prefer to attack pilots and other sensitive areas with AP. HE is much better suited to damaging wings and tails, in my opinion.

 

Observe the following examples of the apparent lethality zone of 30mm HE:

 

Spoiler

 

 

The hit ahead of the cockpit as well as the hit on the port wing failed to seriously injure/kill the pilot. Note that when a pilot is heavily wounded, he will fall unconscious temporarily. Upon regaining consciousness, a heavily wounded AI pilot will attempt to evade (sluggishly) and typically black out again under very light G forces. Crashing is inevitable.

 

If the AI pilot doesn't enter the unconscious/dead slumping animation, he's only lightly wounded, if at all.

 

In the following example, I get hits on both sides of the cockpit, but I believe they are too far away to be effective (in this instance, at least):

 

Spoiler

 

 

And finally, with this last example, the two hits nearer to the cockpit are clearly fatal:

 

Spoiler

 

 

Overall, it would appear as though armor (both glass and steel) is impervious to even 30mm explosive damage.

[BlitzPig_EL]

Regardless of the debate in this thread, I think it's safe to say that the B17 was one tough old bird.

Edited November 17, 2021 by BlitzPig_EL

[Jaws2002]

3 hours ago, BlitzPig_EL said:

Regardless of the debate in this thread, I think it's safe to say that the B17 was one tough old bird.

 

Yep. B-24 was bigger, had longer range and heavier bomb load, but was easier to shoot down that B-17.

 B-17  was a tough old bird.

Edited November 17, 2021 by Jaws2002

[oc2209]

Before I let this thread go, I've got one last example of AP ammo at its most efficient. Compare to the inconsistency of the 30mm in killing the pilot:

 

Spoiler

 

 

The burst was 24 rounds of 20mm AP Russian. The range was approximately 150m. There were apparently 4 hits, 2 to the armored backrest, 2 to the prop. Prop hits are always, or almost always, ineffectual; even when HE.

 

As we can imagine, if there was a mixed ammo belt, the probability of HE shells hitting the backrest armor--and thus being negated--would be quite high with only 2 rounds actually hitting the backrest in this example.

 

For that reason, I would actually prefer a higher proportion of AP than 1/3 in my belts. Alas.