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Comparing HMG Damage, and issues with .50 cals


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To be blunt about my feelings as a customer: I am certainly sympathetic to software limitations as someone who spent some time in that industry. I would never try to disrespect anyones work either. But I dont plan to purchase Battle of Normany unless incendiary ammo, or some sort of workaround approximating its effects added to the USAF aircraft. 

 

I have no regrets about getting this game, but its tough to swallow the .50 BMG model that comes with it. Both from a historical accuracy (lack of API model OR approximation of its effect) AND the massive discrepancy in weapon performance as highlighted in this test.

 

2,000% discrepancy in the effectiveness of the weapons?? From my engineering background, thats an eye poppingly large difference in performance between three systems that are very similar in most characteristics.

 

1g of PETN explosive has 5.8kj of chemical energy. Far less than the kinetic energy that any of these bullets has. A .50 cal ball round at 100 yards has by comparison, 18Kj-20Kj of kinetic energy. 

 

Now before people nit pick me to death and yes I know the bullet wont always dissipate its full Ke etc and chemE and Ke are different, blah blah blah. I will hold that constant and assume both bullets will dissipate their full Ke and Chem E into a target.

 

Lets stick to a simple (and I do mean simple) gut check. If we add 1g of PETN to a .50 cal round it would have a potential for a total energy dissipation of ~25Kj. Vs lets say ~19Kj (middle of range) of energy dissipation for a ball round.

 

Thats a roughly 31% increase in the MAXIMUM possible destructive energy dissipated into a target. 

 

Does it seem intuitively correct that a 31% increase in a projectiles' total destructive energy will cause that projectile to do ~2000% MORE damage to a target? 50% more, 75% more, hell even 200% more is believable. I dont mean to disrespect anyones work, but this answer just seems incorrect to me, by an order of magnitude.

Edited by VA_chikinpickle
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On 1/21/2021 at 2:18 PM, VA_chikinpickle said:

To be blunt about my feelings as a customer: I am certainly sympathetic to software limitations as someone who spent some time in that industry. I would never try to disrespect anyones work either. But I dont plan to purchase Battle of Normany unless incendiary ammo, or some sort of workaround approximating its effects added to the USAF aircraft. 

 

I have no regrets about getting this game, but its tough to swallow the .50 BMG model that comes with it. Both from a historical accuracy (lack of API model OR approximation of its effect) AND the massive discrepancy in weapon performance as highlighted in this test.

 

2,000% discrepancy in the effectiveness of the weapons?? From my engineering background, thats an eye poppingly large difference in performance between three systems that are very similar in most characteristics.

 

1g of PETN explosive has 5.8kj of chemical energy. Far less than the kinetic energy that any of these bullets has. A .50 cal ball round at 100 yards has by comparison, 18Kj-20Kj of kinetic energy. 

 

Now before people nit pick me to death and yes I know the bullet wont always dissipate its full Ke etc and chemE and Ke are different, blah blah blah. I will hold that constant and assume both bullets will dissipate their full Ke and Chem E into a target.

 

Lets stick to a simple (and I do mean simple) gut check. If we add 1g of PETN to a .50 cal round it would have a potential for a total energy dissipation of ~25Kj. Vs lets say ~19Kj (middle of range) of energy dissipation for a ball round.

 

Thats a roughly 31% increase in the MAXIMUM possible destructive energy dissipated into a target. 

 

Does it seem intuitively correct that a 31% increase in a projectiles' total destructive energy will cause that projectile to do ~2000% MORE damage to a target? 50% more, 75% more, hell even 200% more is believable. I dont mean to disrespect anyones work, but this answer just seems incorrect to me, by an order of magnitude.

My feelings exactly.  I'd like to add that the basics of this problem have been understood for literally months.   The OP has only put some numbers to it, but we've known that this has been the situation for a long time now.  Devs PLEASE do something about this!

On 1/21/2021 at 11:29 AM, CountZero said:

Again they aint gona do a thing about it in any near future, you guys are waisting your time:

It's wasting not waisting.   I usually don't correct spelling, but you have done this multiple times now.

On 1/21/2021 at 6:37 AM, Black-Witch said:

The authors state, "The Browning .50 M2 is an undistinguished performer, particularly when compared to the 12.7mm Berezin. The relatively small incendiary content in the .50 (0.9g compared to 2g) gives the Soviet round a flying start which it adds to with its higher rate of fire, and the .50 round is lighter as well.

Perhaps on a one for one basis the M2 .50 is a mediocre performer, but one always has to remember that the average US plane carries 3x as many as almost any other fighter.   That makes a HUGE difference and it's one of the reasons the US didn't feel they needed cannons.

Edited by BCI-Nazgul
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5 hours ago, RedKestrel said:

This may sound strange but the recent bug where the .50cals were doing zero damage against enemy planes after an update gives me hope that they are actually looking at it again and accidentally messed it up lol.

I agree.  There is no reason to turn off component damage exempt if someone was testing the aero effects from the 50s.  

 

5 hours ago, QB.Shallot said:

You know the funniest part is for the first hour or so playing with the bug, I didn't think much was off. It just seemed to me like my aim must have been bad that particular day.

We flew for a day and a half, and didn't even realize there was a bug until we found it on the forum.  We are so use to 50s doing nothing but a pk, it was just life as usual.  🙄

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I'm gonna point out too, assuming my math is correct that 84 .50 cal impacts that made perfect cookie cutter circular holes would cause 16.5 inches square (40cm) of holes in the wing. if it's a trough and through you would double that. 

 

something is wrong here.  

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3 hours ago, VA_chikinpickle said:

To be blunt about my feelings as a customer: I am certainly sympathetic to software limitations as someone who spent some time in that industry. I would never try to disrespect anyones work either. But I dont plan to purchase Battle of Normany unless incendiary ammo, or some sort of workaround approximating its effects added to the USAF aircraft. 

 

I have no regrets about getting this game, but its tough to swallow the .50 BMG model that comes with it. Both from a historical accuracy (lack of API model OR approximation of its effect) AND the massive discrepancy in weapon performance as highlighted in this test.

 

2,000% discrepancy in the effectiveness of the weapons?? From my engineering background, thats an eye poppingly large difference in performance between three systems that are very similar in most characteristics.

 

1g of PETN explosive has 5.8kj of chemical energy. Far less than the kinetic energy that any of these bullets has. A .50 cal ball round at 100 yards has by comparison, 18Kj-20Kj of kinetic energy. 

 

Now before people nit pick me to death and yes I know the bullet wont always dissipate its full Ke etc and chemE and Ke are different, blah blah blah. I will hold that constant and assume both bullets will dissipate their full Ke and Chem E into a target.

 

Lets stick to a simple (and I do mean simple) gut check. If we add 1g of PETN to a .50 cal round it would have a potential for a total energy dissipation of ~25Kj. Vs lets say ~19Kj (middle of range) of energy dissipation for a ball round.

 

Thats a roughly 31% increase in the MAXIMUM possible destructive energy dissipated into a target. 

 

Does it seem intuitively correct that a 31% increase in a projectiles' total destructive energy will cause that projectile to do ~2000% MORE damage to a target? 50% more, 75% more, hell even 200% more is believable. I dont mean to disrespect anyones work, but this answer just seems incorrect to me, by an order of magnitude.

 

The OP did not show that the HE rounds in the game are 2000% more effective in general: they showed that they are 2000% (ie 20 times) more effective against aircraft skin. The total damage to the target is not measured by this test, understandably. I do not think we can work that out from testing, but it is reasonable to assume that internal structures are disproportionately damaged by AP rounds. 

 

If you compare a .50 cal ball round and MG131 HEI-T at 100m range they have almost the same total energy, but ~50% of the HEI-T's is in CE. So results depend on how much of each of the available energy types goes into skin vs structure damage.

 

Assuming no obvious error in the total energy available on hit, the game is in effect saying that the proportion going into skin is low for KE and high for CE. You do not have to plug in particularly odd numbers to generate a 5-1 ratio of energy into skin for HE over AP,  and if you assume 1% of KE is used for entry and 1% for exit, with 50% of CE affecting skin, and damage proportional to Joules, you can get to towards 15/1 skin damage for HE/AP (1500%, gasp!!). The ratio of structural damage will be 0.8/1 in this case assuming the same % wastage: because the quantity of KE used to penetrate the skin is so low.

 

Running the same set of assumptions for the .50 cal API-T I get APIT/AP ratios of 12/1 for skin damage. That may be an exaggeration as I do not think that thermite would have as much bias towards skin damage as HE, but it does illustrate the point that relatively small changes to the bullet composition can make very large differences to the potential outcomes.

 

edit: thought I would add a simple illustration of how two shells with the same total energy could end up with odd looking damage ratios. This is just a thought experiment, I do not know what the numbers should be, but it does illustrate why "2000% must be wrong" is not an ideal way to look at this problem, although I would certainly be more comfortable with ~ 5:1.

 

765661008_DMratios.thumb.JPG.d776ee2e80f9de3297ca4fa0fca91de6.JPG 

 

 

Edited by unreasonable
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That's an understandable assumption based off a perfect through and through. But aircraft aren't balloons.

 

If you fire 15 rounds into this from 6 o'clock:

occnvai427messerschmitt-bf-109-f-mono-speccati95aviation-of-ww2iti688limitstart1-obrazek_5shopkag1.jpg.ea0cfb9ce94bf98c721c5d88bd833e58.jpg

I'd wager you aren't going to get that many perfect entry and exit holes.

 

That in itself creates huge complexities in terms of modelling. It does seem currently we have a set damage amount based off of the ballistics model (which is excellent) that doesn't take into account the possibility of a bullet transferring significant amounts of its KE into skin damage. 

 

This gets said a lot, but it seems we have a best case HE hit every time and a worst case AP hit every time. If they have to be singular, bringing more balance to those cases might help create a better environment.

Edited by Cass
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The impact angle of the round and the aircraft's damage model seem to play a role in this too. Tested by flying a 110 G2 in single player and letting the AI in various aircraft shoot me with unlimited ammo, While staying in auto level.  The results were interesting for the P-51. 750 rounds were fired and 65 registered as hits. Oblique hits to the fuselage seemed to ricochet off. Tacview shows a shower of rounds deflecting off the rear fuselage. Which, seems impervious to damage. Visually, it never changes states despite all the hits.  The tail wheel and the central part of the stabilizer seem to be immune from damage. The only way to damage or destroy the stabilizer / elevator is to shoot off one of vertical stabilizers. At which point the craft loses stabilizer / elevator control, but is stable and can still use pitch trim to control the aircraft. 

 

The 110 seems to have one of the most flawed damage models. Structurally it seems to have only a few segments that can be damaged. The outer wing tips, the vertical stabilizer, the fuel tanks and the cockpit. The rear fuselage will take visual damage from HE, but it doesn't appear to effect the aircraft in a meaningful way. Most of the kills came from fire or explosions from the fuel tanks inboard of the engines or pilot kills. 

 

There seems to be a ballistics computation for ricochet being done based on impact angle. However this doesn't seem to take into account over match. Given the diameter of the .50 and thickness of the aircraft skin, the .50 call should not be ricocheting off the fuselage. The ricochet issue is more obvious with the P-51, since the rounds converge at an oblique angle which exacerbates the problem.  The number of ricochets and some of the more questionable damage models may factor in why the 50 cal seems under-powered. I tested, the 109 G2, Fw-190A8,  Mig,  P-51, P-47 and the Yak-9 against the 110. Center mounted weapons with HE tended to preform best. They tended to hit the fuel tanks and ignite them more quickly with less rounds. AP needed roughly 3 times as many hits to ignite the fuel tanks. No weapons seemed capable of destroying the structural integrity of the 110 though. I've attached a track showing all the rounds bouncing off the 110. 

ricochet.thumb.PNG.f098ec30b5483f59a9d37368e9d12df8.PNG

 

 

P5_V_110_Kill_track.rar

Edited by Yak_Panther
put up two of the same pic, stabs = elevator
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22 hours ago, Cass said:

That's an understandable assumption based off a perfect through and through. But aircraft aren't balloons.

 

If you fire 15 rounds into this from 6 o'clock:

occnvai427messerschmitt-bf-109-f-mono-speccati95aviation-of-ww2iti688limitstart1-obrazek_5shopkag1.jpg.ea0cfb9ce94bf98c721c5d88bd833e58.jpg

I'd wager you aren't going to get that many perfect entry and exit holes.

 

That in itself creates huge complexities in terms of modelling. It does seem currently we have a set damage amount based off of the ballistics model (which is excellent) that doesn't take into account the possibility of a bullet transferring significant amounts of its KE into skin damage. 

 

This gets said a lot, but it seems we have a best case HE hit every time and a worst case AP hit every time. If they have to be singular, bringing more balance to those cases might help create a better environment.

In the encounter reports there are many mentions of "pieces falling off". More over, there are a couple of post-action reflection that mentioned directly how the armour pierce rounds caused pieces coming while the incendiary didn´t.

The ap caused skin damage. Not only neat holes.

 

Ap effect.png

Lack of AP.png

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2 hours ago, HR_Zunzun said:

In the encounter reports there are many mentions of "pieces falling off". More over, there are a couple of post-action reflection that mentioned directly how the armour pierce rounds caused pieces coming while the incendiary didn´t.

The ap caused skin damage. Not only neat holes.

 

Ap effect.png

Lack of AP.png

 

Very interesting loadout there.  Sorry if I missed it, but what aircraft and at what date was the all incendiary loadout used?  Thanks.

 

Happy landings,

 

Talisman

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Just now, ACG_Talisman said:

 

Very interesting loadout there.  Sorry if I missed it, but what aircraft and at what date was the all incendiary loadout used?  Thanks.

 

Happy landings,

 

Talisman

 

Some of the P-47 reports use the word "incendiary" in the text, but also state the ammunition used as API or AP & I. Not sure if the latter is usually API or a mix of AP and I. Not these two - from which the excerpts came - they do not have notes on the bottom detailing ammo use.

 

http://www.wwiiaircraftperformance.org/p-47/er/353-duncan-5jan44.jpg

http://www.wwiiaircraftperformance.org/p-47/er/353-beckham-1dec43.jpg

 

I think it is also worth noting that although API had become the preferred ammunition for fighter groups, there could well have been temporary shortages from time to time. 

Edited by unreasonable
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I believe the AP & I is describing a mixed belt.  The 370th FS (P-51B) reports from spring of 44 are very specific about the mixed belts being used.  Interestingly, the other two squadrons of that group report just using pure API.  I think squadron preference played a factor here as with convergence settings.  Likewise tracer usage seems to have varied from unit to unit (some used tracers, some didn’t, some used tracers as a low ammo warning at the end of the belt).

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On 1/22/2021 at 6:27 PM, Yak_Panther said:

The impact angle of the round and the aircraft's damage model seem to play a role in this too. Tested by flying a 110 G2 in single player and letting the AI in various aircraft shoot me with unlimited ammo, While staying in auto level.  The results were interesting for the P-51. 750 rounds were fired and 65 registered as hits. Oblique hits to the fuselage seemed to ricochet off. Tacview shows a shower of rounds deflecting off the rear fuselage. Which, seems impervious to damage.

This is super interesting. I went back and took a look at our tacview files and see the same thing. We were always shooting at the left wing of a 109 or 190, and it looks like roughly half of the .50 cal rounds are ricocheting off the wing. Does anyone know definitively how this is handled in the game engine? For all I know, this is just an artifact in tacview...

 

 

bullet-ricochet.gif

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If there are ricochets off the wing, for a firing plane slightly above the target, they should be going up, as some are in Yak_Panther's picture.   The other possibility, for some of those going down, especially the rather slow ones, is that they are not ricochets, but shots that have passed through the target and have lost a lot of speed in the process.  Shots can definitely go right through some parts of an aircraft in the game such as the vertical stab (of the 109 :) ). I have not tested wings specifically but it should be possible to do it.  ( I have now).

 

That is all assuming that Tacview is showing what is actually happening, which in the case of bullet paths has not always been the case in the past.

 

Here is a ricochet off an He111 wing.

1715256269_WINGRICOCHET.thumb.jpg.ce5824c224755aa96eb5f00b21daac15.jpg

 

And a shot going through the wing ( a bit harder to see).

 

1923968040_tHROUGHWING.thumb.jpg.9b0a2461a889231cfc7769ee66087757.jpg

Edited by unreasonable
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The table for the US AP .50 rounds references ricochets. Specifically they will be redirected, ricochet, a maximum of 2 times. What happens after the second redirection and under what circumstances a round shall be redirected is not mentioned in that part of the code though; I'd expect that to be in the engine code somewhere.

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On 1/22/2021 at 6:31 AM, unreasonable said:

dit: thought I would add a simple illustration of how two shells with the same total energy could end up with odd looking damage ratios. This is just a thought experiment, I do not know what the numbers should be, but it does illustrate why "2000% must be wrong" is not an ideal way to look at this problem, although I would certainly be more comfortable with ~ 5:1.


Thank you for doing some quick plausibility checks. I absolutley agree with your statement  of being more comfortable with 5:1. The problem with the original test is it’s lacking the plausibility check you did to put it into real world context (like you already explained), as well as the rather arbitrary chosen damage level ranges. Many people see the 2000% difference and start hyperventilating.

IMO it’s an ap vs HE Problem and not a General conspiracy against .50 of the entire dev team. Most probably a misrelation of skin to structural damage.

Edited by =EXPEND=13SchwarzeHand
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19 minutes ago, =EXPEND=13SchwarzeHand said:

IMO it’s an ap vs HE Problem and not a General conspiracy against .50 of the entire dev team.

 

Which could be tested using the 20mm ShVAK with HE and AP exclusive loadouts. I just did a few dogfights yesterday, due to lack of a proper test setup and lack of energy to create one, and imho HE did a lot more than AP on the same gun. Which is 100% the opposite of what we used to have when I did proper testing the last time (couple of years ago).

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On 1/20/2021 at 6:09 PM, CountZero said:

You and others can spend weeks months on testing something that they can do in a day, and if things are ok they would have no problem show with that tool that all is all ok with AP ammo in game and problem is in players heads or in netcode.

 

Respectfully, the problem is not in players heads. There is a very real problem if the 50 cal cannot create "level 2" aerodynamic damage before the wing falls off, and it is worthwhile testing in an actual game situation (real game clients, real server, real network) because those are the real flight conditions for real players.

 

On 1/21/2021 at 10:36 AM, QB.Creep said:

You guys can argue the minutiae until the cows come home, but the bottom line is that there is very clearly a problem. It's up to the devs to decide how to remedy it. 

 

Yep. This. Just look at the actual tested numbers. Do they look reasonable? Not to me. In particular, they confirm what a lot of Allied pilots have been saying -- unless you get a pilot kill with the 50s, you're not gonna even slow the other guy down.

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23 hours ago, unreasonable said:

I think it is also worth noting that although API had become the preferred ammunition for fighter groups, there could well have been temporary shortages from time to time. 

 

 

I love the way you hint to the people running the MP servers to put in a limitation for the availability for allied API by saying this...

 

Should we really go down that path? From all the books I've read about this, it's clear that by the beginning of 1944 I believe the axis had a shortage on pretty much everything....whilst the allies had an abundance of supplies?

 

Try harder...

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Just now, NIK14 said:

 

 

I love the way you hint to the people running the MP servers to put in a limitation for the availability for allied API by saying this...

 

Should we really go down that path? From all the books I've read about this, it's clear that by the beginning of 1944 I believe the axis had a shortage on pretty much everything....whilst the allies had an abundance of supplies?

 

Try harder...

 

Grow up: or if you cannot do that, get treatment for your paranoia. I am not interested in MP, and do not care whether one side or other has some handicap or advantage. I am not hinting anything.

 

I am pointing out that the ammunition usage of units in WW2, as reported in their combat reports, would sometimes reflect was was available instead of what was thought ideal. 

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1 hour ago, unreasonable said:

Grow up: or if you cannot do that, get treatment for your paranoia. I am not interested in MP, and do not care whether one side or other has some handicap or advantage. I am not hinting anything.

 

I was reasonable in my response...this from you is unreasonable...pun intended.

 

1 hour ago, unreasonable said:

I am pointing out that the ammunition usage of units in WW2, as reported in their combat reports, would sometimes reflect was was available instead of what was thought ideal. 

 

This is exactly what I was pointing out in return of your previous comment....

Edited by NIK14
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The perennial argument of those that downplay the concerns about .50 cal damage is that "they should not cause aerodynamic damage because they pass straight through the target". This business with the ricocheting of bullets doesn't make much sense if that claim is to be believed. If something is being deflected either inside the wing structure (striking a spar for instance), then it should be causing more structural damage and larger exit holes. If it's ricocheting off of the wing surface (even less realistic), then it would be deforming the wing surface. No matter how you take this information, the .50s are underperforming in their current state.

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On 1/24/2021 at 4:32 PM, NIK14 said:

 

 

I love the way you hint to the people running the MP servers to put in a limitation for the availability for allied API by saying this...

 

Should we really go down that path? From all the books I've read about this, it's clear that by the beginning of 1944 I believe the axis had a shortage on pretty much everything....whilst the allies had an abundance of supplies?

 

Try harder...

1944 Germans had shortage of everything?
Boi Ihope you know, the germans has no fuel problem until 1944 april, when 1 yes 1 american suggested to bomb the syntetic refineries. (luftwaffe had no fuel problem until 1945)

 DefeatGAF23.jpg 

Source:http://www.allworldwars.com/The Defeat of the German Air Force.html

And the germans produced the MOST in 1944: Most tank, planes everything.
Example: They produced 300-500 BF-109 in 1943/month.
In 1944 they increased it to ~1200/month. Oh and they distributed the big factories into little manufactures. 4-5 big factory into 700 little manufacture.
Bf-109:
1943:6418,
1944:14,152
They produced 1500-2000 Panzer IV in 1943, in 1944-1945 they produced 5500. Panther: 1943: 1200, 1944-45:5000.

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34 minutes ago, -[HRAF]Roland_HUNter said:

1944 Germans had shortage of everything?
Boi Ihope you know, the germans has no fuel problem until 1944 april, when 1 yes 1 american suggested to bomb the syntetic refineries.
And the germans produced the MOST in 1944: Most tank, planes everything.
Example: They produced 300-500 BF-109 in 1943/month.
In 1944 they increased it to ~1200/month. Oh and they distributed the big factories into little manufactures. 4-5 big factory into 700 little manufacture.
Bf-109:
1943:6418,
1944:14,152
They produced 1500-2000 Panzer IV in 1943, in 1944-1945 they produced 5500. Panther: 1943: 1200, 1944-45:5000.

now wehr is my bingo card...i thought i had it around here somewhere...

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47 minutes ago, -[HRAF]Roland_HUNter said:

1944 Germans had shortage of everything?
Boi Ihope you know, the germans has no fuel problem until 1944 april, when 1 yes 1 american suggested to bomb the syntetic refineries.
And the germans produced the MOST in 1944: Most tank, planes everything.
Example: They produced 300-500 BF-109 in 1943/month.
In 1944 they increased it to ~1200/month. Oh and they distributed the big factories into little manufactures. 4-5 big factory into 700 little manufacture.
Bf-109:
1943:6418,
1944:14,152
They produced 1500-2000 Panzer IV in 1943, in 1944-1945 they produced 5500. Panther: 1943: 1200, 1944-45:5000.

Wildly off topic, but I can’t help but point out that those production gains were achieved by:


ceasing production of nearly every aircraft except the 109, 190 and 262

 

pressing huge amounts of slave labor into service, resulting in an aviation work force similar in size to that of the US (for a fraction of the output)

 

fudging their numbers to the tune of 8000 fighters in order to keep Speer in Hitler’s good graces

 

cutting every corner possible in actual production, resulting in fighters that were often 20+ mph slower than their specifications, if they even ran or flew at all

 

But hey, the numbers looked good on paper.

 

And those stupid Americans.  They just put together a target list of potentially vital choke points in the German economy with the aid of businessmen who had worked in Germany extensively before the war.  And then once they reached a point of being able to actually bomb those targets regularly and observe the results, it took an entire four months to arrive at the optimal targets(fuel and rail infrastructure) to cripple German industry (whose production started dropping off a cliff in September, before any Allied soldier had set foot in the Reich).  What a bunch of idiots.

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Just now, QB.Creep said:

No matter how you take this information, the .50s are underperforming in their current state.

 

Under performing relative to what? The physical reality of .50 cal AP ammunition vs aeroplane wings? The game's 13mm HE?  Or gamer desire that a burst of .50 cals should cripple a target in MP?  You cannot agree on the solution to a problem if you have inconsistent definitions of what the problem actually is.

 

The OP points out a difference in the ratios between the number of shots required to reach level 3 damage - ie the most severe level of surface damage possible consistent with the plane still being flyable. I think everyone commenting so far finds the ratio excessive, but they often do not say why. 

 

Suppose you thought 5:1 is reasonable.  You can adjust the ratio by adjusting either, or both, of the quantities.   20:1 can go to 20:4  or 5:1  or 10:2

Clearly these require different adjustments to the model, not all of which will make  .50 cal AP capable of noticeably slowing down a target fighter by increasing it's drag.

 

If the just ratio of modelled surface damage is "wrong", is that because the damage from 13mm HE is too high, the damage from .50 cal too low, or both?

 

Or are you simply asking for a .50 cal API shell to be modelled, in addition to the current .50 cal AP?

 

FWIIW my own views are that the .50 cal AP surface damage is actually plausible, but it would not bother me if it was ~doubled. The 13mm HE I find wildly implausible. API is not modelled but should be,  not as a bodge on all .50 cal AP,  but explicitly, as should other incendiaries for other gun types.

 

Then you would have a .50 cal AP bullet with similar characteristics to today's, a 13mm HE bullet with considerably reduced surface effects (both quantity and spread), and a .50 cal API shell with performance somewhere in between.  I am happy to adjust any of those views based on evidence of what the shell types actually did to real planes.

 

Solutions I would regard as unacceptable in a simulation would be to make .50 cal AP behave like a bullet with a significant CE load (API), just in order to appease an MP faction that is frustrated by certain aspects of their targets' flight behaviour. 

 

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It’s not just the .50’s cals that are effected by the ricochet issue though. It’s all AP ammo. 20 mm ap is also largely worthless too. The rounds that impact and ricochet are not causing any damage. Here’s my test of the LA-5 with all AP vs the 110. The AI fired 340 rounds of which 42 registered as hits. The result was only a dead gunner.

 

LA5_V_110.thumb.PNG.70baff054f73891d13fc22a1be21aad8.PNG

An AP round impacting aircraft aluminum obliquely with a reasonable velocity should not ricochet. It in fact would cause greater damage than a round striking perpendicular.  This effect is described and illustrated in the Survivablity Design Guide for US Army Aircraft Volume 1. https://apps.dtic.mil/dtic/tr/fulltext/u2/891122.pdf page 106. A .50 cal AP round striking obliquely to aircraft skin tears a large gash across it’s path. It doesn’t deflect off, without causing any damage.  737598253_ScreenShot2021-01-24at6_42_03PM.png.baf5f1434d658e7db3905ba00b0fb392.png

 

 

 

The reason for this is ballistic overmatch. When the diameter of the round is greater than thickness of the material its impacting; The material fails in a shearing fashion due to the ductile nature of the interaction.

1709002529_ScreenShot2021-01-24at7_01_19PM.thumb.png.fc671ee6ae1c116bb9b94fb8106f3cf7.png

 

 

Overmatch Defined on Page 9.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a954868.pdf

Chart From Page 18.

https://apps.dtic.mil/dtic/tr/fulltext/u2/492302.pdf

 

However, even when rounds impact at oblique angles below a critical velocity and ricochet. They cause significant damage to the surface. In aluminum this results in significant petaling and perforation of the material. Even at impact velocities of 300 meters per second. Below is a pic of the effect of 6.5 mm steel ball impacting 1.27mm aluminum plate (double the thickness of aircraft skin.) and ricocheting.

731253579_ScreenShot2021-01-24at9_26_58PM.thumb.png.62207f26e94fd703f1c590b8f440c08f.png


https://apps.dtic.mil/dtic/tr/fulltext/u2/a030268.pdf

 

link to ballistics formulas with primary source references.
https://www.alternatewars.com/BBOW/Ballistics/Term/AP/AP_Pen_Formula.htm

 

They should either disable the ricochet mechanic for AP rounds against aircraft, or model overmatch and an associated damage multiplier due to the spalling and fragmentation that subsequently occurs due to overmatch.

skirmish.2021-01-24_17-33-04_00.zip

Edited by Yak_Panther
added pics and zip of track
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4 hours ago, unreasonable said:

just in order to appease an MP faction that is frustrated by certain aspects of their targets' flight behaviour. 

Whole statement self-disqualified in one singe line.

Congratulations.

 

:drinks:

Mike

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Think it would be best if people could stick to what common ground there is; rather than jabbing eachother in the arm over what they don't agree on - or what is up for further detailed evaluation. Letting the thread degenerate down the same path we've seen in the past is only going to water down the original (well made) case presented by @QB.Shallot , the QB team and their contributors.

 

What it seems can be agreed on:

 

- Incendiary rounds need to be added at some point fairly soon in future... in order to bring weapon load-outs in line with historical accuracy. This will require resources to be dedicated from the dev. team and will probably come with potential delays to planned content.

- Aerodynamic damage is underwhelming with the M2 .50 calibre and this appears to be out by a significant factor, requiring further evaluation by the dev. team.

- Surface damage is excessive when using HE rounds with weapons of calibre 12.7 to 13mm.

- Ricochet effects (perhaps linked to prev. work on TC) appear to be contributing to inefficiencies with lower calibre weapons.

 

Is there a real need to be more specific than that here? the details of the rest could and arguably (should) be established by the actual developers.

 

No one needs to be disqualifying anyone, because we have common ground - and we have an good excellent development team that can potentially re-assess this when they are allocated the resources to do it. What was made clear in comments by Jason at the end of last year is that the team doesn't have the time and resources allocated to looking at it right now.

 

Cheers, Aurora

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Just now, Yak_Panther said:

It’s not just the .50’s cals that are effected by the ricochet issue though. It’s all AP ammo. 20 mm ap is also largely worthless too. The rounds that impact and ricochet are not causing any damage. Here’s my test of the LA-5 with all AP vs the 110. The AI fired 340 rounds of which 42 registered as hits. The result was only a dead gunner.

 

LA5_V_110.thumb.PNG.70baff054f73891d13fc22a1be21aad8.PNG

An AP round impacting aircraft aluminum obliquely with a reasonable velocity should not ricochet. It in fact would cause greater damage than a round striking perpendicular.  This effect is described and illustrated in the Survivablity Design Guide for US Army Aircraft Volume 1. https://apps.dtic.mil/dtic/tr/fullt ext/u2/891122.pdfpage 106. A .50 cal AP round striking obliquely to aircraft skin tears a large gash across it’s path. It doesn’t deflect off, without causing any damage.  737598253_ScreenShot2021-01-24at6_42_03PM.png.baf5f1434d658e7db3905ba00b0fb392.png

 

 

 

The reason for this is ballistic overmatch. When the diameter of the round is greater than thickness of the material its impacting; The material fails in a shearing fashion due to the ductile nature of the interaction.

1709002529_ScreenShot2021-01-24at7_01_19PM.thumb.png.fc671ee6ae1c116bb9b94fb8106f3cf7.png

 

 

Overmatch Defined on Page 9.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a954868.pdf

Chart From Page 18.

https://apps.dtic.mil/dtic/tr/fulltext/u2/492302.pdf

 

However, even when rounds impact at oblique angles below a critical velocity and ricochet. They cause significant damage to the surface. In aluminum this results in significant petaling and perforation of the material. Even at impact velocities of 300 meters per second. Below is a pic of the effect of 6.5 mm steel ball impacting 1.27mm aluminum plate (double the thickness of aircraft skin.) and ricocheting.

731253579_ScreenShot2021-01-24at9_26_58PM.thumb.png.62207f26e94fd703f1c590b8f440c08f.png


https://apps.dtic.mil/dtic/tr/fulltext/u2/a030268.pdf

 

link to ballistics formulas with primary source references.
https://www.alternatewars.com/BBOW/Ballistics/Term/AP/AP_Pen_Formula.htm

 

They should either disable the ricochet mechanic for AP rounds against aircraft, or model overmatch and an associated damage multiplier due to the spalling and fragmentation that subsequently occurs due to overmatch.

skirmish.2021-01-24_17-33-04_00.zip 1.4 MB · 0 downloads

 

Thank you for posting interesting references.

 

When you say page 106 of 891122 I assume you mean the page in the pdf, not the original page numbering, since that is about toxic smoke hazards. As far as I can see, this section says that shots at 90 degrees make small holes, and the more oblique the angle the bigger the hole. Who knew? Thank God for Big Government. ;) 

 

One could actually test if this is replicated in the game, although probably only with static tests, by presenting a surface to a gun at a variety of angles - not sufficiently oblique to create ricochets -  and measuring the number of hits required to create level 3 damage. 

 

Here is page 106 of the pdf for the majority of the readers of this thread who will not actually look at the evidence, but just cheer or jeer depending on which "side" it purports to support.  Please show me where it says that a Xmm projectile cannot ricochet off a plate less than Xmm thick. The other diagram you show (Effect in variation etc) also does not make the point you are trying to make about ricochets: it says quite clearly "tendency to fail in shear" and "more difficult to fail in shear".  This is a probability, not an absolute limit. Do ricochets happen in the sim more often than they should? Perhaps, but this document does nothing to answer this question. Quite clearly, the tendency to ricochet in the game is a function of the impact angle. (Also possibly the level of damage - more damage = more ricochets, although that is just an observation: not systematically tested). 

 

What bothers me more is that HE rounds do not seem to ricochet, as far as I am aware they always go off on the surface, which I am sure is incorrect.

 

44009482_page106ballistics.thumb.JPG.253cc34c716e407ba8c9ce51daab4af5.JPG

 

 

 

 

 

It is interesting that in 954868 there are AP penetration tables for 90mm AP vs 3 inch armour. 90mm = ~3.5 inches, so "overmatched" according to this definition , which is no more than a useful rule of thumb. The tables only go up to 70 degrees obliquity. Why do you think that is?

 

 

 

 

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@unreasonable

I assume the difficulty of measuring surface area damage on a sheer of that size would be challenging. Also it would be difficult to create a model for them.

 

I think rule of thumb and best case/worst case models shouldn't be discounted. We aren't going to get an overly complex DM due to the number of rounds in the air. The calculations would drastically affect performance.

 

Another variable is the type of material used. This is the difference between 2 different types of Aluminium:

Screenshot_20210125-104003_Drive.thumb.jpg.cefddf39c6b41c65d0c24edd6cd50634.jpgScreenshot_20210125-103944_Drive.thumb.jpg.2d5aadc48f4cc7c58d588c472014f54d.jpg

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@Cass I have no problem with rules of thumb as such, but in the case of a highly complex system where only a few of the inputs and mechanisms can be modelled explicitly, if it is just as easy to insert a probability table as to insert "if x then y", then I would prefer the probability table.

 

Yak_Panther is saying that 13mm projectiles cannot ricochet off aircraft skin. Because "over match".

 

The developers think otherwise, and have a model that incorporates that. So Yak_Panther needs to prove his assertion: the documents he links do nothing of the kind.  Still to read your link though - need more coffee!

 

 

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@unreasonable

Might need a big cup! There's some math's in there that's way over my head but it seems to be an actual working model for assessing upper and lower limits of damage created by AP rounds on aircraft skin. 

 

The example for running from page 58-60 shows a .30 calibre round striking 0.090 inches of aluminium at 60 degrees.

 

Upper limit: 3 inches

Lower limit: 0.658 inches

 

 

Interestingly, lower velocities actually appear to do more damage.

 

Edited by Cass
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Oh sorry I only looked at the pics you posted. Can you give me the page number pls? @Cass

I scanned through the report and i cannot find anything that relates damge size to probability of occurance, but maybe I´m blind. Of course this would be the relevant probablity and having any section on some probability doesnt help...

Edited by =EXPEND=13SchwarzeHand
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