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Comparing HMG Damage, and issues with .50 cals


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12 hours ago, QB.Creep said:

I understand what you're saying, however there was very little deviation from one test to the next in terms of the number of hits required to achieve the desired effect. We did more testing than we have reported here on other aspects of the sim that I will not mention and came to the conclusion that, for those, we did need much larger sample sizes.

 

I disagree that it is a waste of time. What then should we do, throw our hands up into the air and walk away? Let's not be quitters. :)

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.

 

11 hours ago, RedKestrel said:

If you are firing from the dead-six position it seems reasonable (pardon the pun) that the bullets would pass through the aileron and/or flaps as well as the wing, and (would do so pretty consistently.)

 

But if the case is that the control surfaces are absorbing some of the energy of the rounds, then it shows the HE rounds are still doing excessive damage, since they too would be hitting flaps or ailerons before the wing. 

Anyway, what this test best shows is the relative difference in effectiveness between the various HMGs. I wonder what would happen if you were able to test the MG131/UBS as AP only. Is it simply a matter of overperforming HE, or something with the M2 in particualar?

It can be done in mods, just replace MG131 HE ammo with its AP ammo so it will fire only 13mm AP, same to russian 12.7 with its HE replaced with its AP, and same thing would happend as with american 0.50 AP only, problem is as it was always they buffed HE and make AP more week, like they said in DDs and updates from that 4.005 somehow before 4.005 there was perception that AP ammo does more damage and HE is to week, and this is how we ended up with this week AP we have since 4.005. Its not like its mistery on what happend all is pointed out many times.

 

Edited by CountZero
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Worth adding, in case anyone is confused about what the damage levels really look like.

 

Here are the three stages of surface damage on an He111 outer wing section, chosen because this is easy to get with the onboard MG81 without anything falling off. 

 

1701202296_He111level1crop.thumb.jpg.ca6c394c632e7ca6381c93a3f17fd3a0.jpg Level 1

414245451_He111level2crop.thumb.jpg.a6af5d3ca2fd391be97f5539f1c0dccf.jpg Level 2

1386282883_He111level3crop.thumb.jpg.adfdd87f9d684af4958168ed2caf8cca.jpg Level 3

 

 

Here is 109 G14: middle wing hit box. First two done with MG81, last with MG131. The line of damage through the inner side of the cross means the section is close to breaking off.

 

 

1008263238_109level1crop.thumb.jpg.2470e94d52c69a1efd49dcdbffde1107.jpg Level 1

1711232111_109level2crop.thumb.jpg.517fd6360f4536e84a0e9ef2f67c76ab.jpg Level 2

1267620893_109level3crop.thumb.jpg.616b27befb4f28dc432ac5ea108c6a8e.jpg Level 3

Edited by unreasonable
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So where should the Browning .50 sit compared to the MG131 and the UB? How many rounds should be needed to cause the damage described above?

 

In the middle, between them both, with the UB being the best of the three. This according to A.G. Williams & Dr E. Gustin in "Flying guns WWII".

 

Here is the data they work from:

 

UB* 12.7mm x 108mm: 840 m/sec velocity, 13 rounds per second synchronised, 17 rounds per second un-synchronised, 48gm round with 2gm of HE.

 

M2 .50": 12.7mm x 99mm, 890 m/sec, 13 rps unsynchronised, 43gm bullet 0.9gm incendiary in the M8 round. so slightly lighter round and less Chemical energy.

 

MG131 13mm x 64mm:

AP 710 m/sec, 38.5gm 15 rounds per sec'. Lower velocity, less weight.

HE 750 m/sec, 34gm 1.2gm of HE. Lower velocity, less weight and less chemical energy than the USB.

 

The authors use a formula to get a "score" for comparing different weapons: 

 

"momentum" = projectile weight multiplied by the muzzle velocity, to calculate the kinetic energy.

 

Chemical energy: they treat HE and Incendiary as the same because fire was a big killer of aircraft, and although they "work" differently one is not more effective than the other because of the random way rounds hit different parts of an aircraft, so the score can be considered as an average when comparing weapons using HE or Incendiary or even HEI.

 

The authors say the comparison between the effect of kinetic and chemical energy is a difficult and complex subject, and quote the example of a delayed fuze HEI round, it will first cause kinetic energy as it strikes the structure, then chemical blast energy as the HE detonates, thirdly the shell fragments will inflict further kinetic energy and finally the incendiary, spread by the explosion, could cause further chemical (fire) damage.

 

Once each cartridge's score is calculated they then take into account the different rounds in a belt or magazine, they also allow for tracer rounds, which "can" reduce the amount of HE in certain shells, and finally the rate of fire is calculated, however, as in this case we are talking about a few rounds doing measurable damage I shall include only their single cartridge scores and the "average" score of rounds within a belt.

 

Here are the authors scores for these 3 HMG's.

 

MG131 AP: single cartridge score 27. comparison score 3.

MG131 HE: single cartridge score 34. comparison score 3.

M2 .50 API: single cartridge score 46. comparison score 4.5.

UB*: single cartridge score 57. comparison score 6.

 

According to the authors, the Browning .50 M8 round sits almost exactly between the MG131 and the UB* for damage potential of a single round and the average damage of several rounds hitting.

 

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.

 

The UB* (universal gun) came in 3 forms:

UBT, fitted in turrets.

UBK, fixed wing installation. 1050 rpm.

UBS, synchronised. 800 rpm.

 

It should be remembered that the US M8 round only became available in late '43 early '44, roughly when the P-51B's arrived, before that there were 2 rounds for the M2 .50, the M2 AP round and the M1 Incendiary round, these 2 would have been used in the P-39, P-40 and P-47 before the M8 became available.

 

Witch

 

 

 

 

 

 

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Just now, Black-Witch said:

So where should the Browning .50 sit compared to the MG131 and the UB? How many rounds should be needed to cause the damage described above?

 

In the middle, between them both, with the UB being the best of the three. This according to A.G. Williams & Dr E. Gustin in "Flying guns WWII".

 


<snip>

 

 

I suspect everyone here has read the Gustin and Williams stuff: it really does not help at all in this case.

 

AP vs HE create types of damage in different ratios, which is what the game has to model to get a plausibly realistic outcome.  The OPs are concerned with the surface damage, but not the internal structural damage, so averaging out the total numbers using an index score conceals rather than adds information. You have to have a view on how much of the total energy from each round - which is reasonably easy to calculate - is transferred to the skin, passes through into the structure, or is wasted in space. Then you have to have a view on the vulnerability to damage of various aircraft components that absorb the energy, and the wider effects on the aircraft's performance.

 

G&W's index cannot do any of that.

 

(BTW: "momentum" = projectile weight multiplied by the muzzle velocity, to calculate the kinetic energy." - actually, no. The kinetic energy is = 1/2 * m * V^2 , which Gustin et all quite explicitly do not use, giving bizarre reasons. They use momentum to calculate kinetic damage. Every other source I have found that does this kind of index uses kinetic energy instead.)

 

 

Edited by unreasonable
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A generalistic score is great in terms of a guide but it's how they damage that's the key to simulating their effectiveness.

 

Sub 20mm HE calibre rounds are largely ineffective in actually causing additional damage, that's why they were replaced with incendiary rounds. Hit a spar with each round and you will see little difference as the explosive potential of the round doesn't create enough pressure to do additional damage.

 

The Minengeschoß rounds were so effective because the unarmoured surfaces and internals of a plane are relatively weak and the pressure created by the explosion causes ruptures and massive amounts of damage. We don't see that but it’s supposedly in the sim. For some reason, all HE seems to have that potential at the moment.

 

The counterpoint is obviously that, yes HE is borked but where should they both be? Unfortunately that's a difficult question to ask. I think if this was a discussion around 4x equipped planes, then yes there would valid arguments in the current model being correct. But the issue is that when you upscale to an 8x, you begin to see that something is being undermodelled. I don't think anyone has really questioned the P47's firepower, it was known for it. Yet in game it still feels very ineffective. Perhaps the "shredding" element of lot's of hits needs to be modelled in some way if it's possible to divorce the single round damage after a certain point.

 

 

You can see below a modern day Raufoss (.50) round vs a .50 API.

 

The Rafouss is an absolute beast and a apparently has the same energy output as a Hispano 20mm round. Yet the actual hole isn't much larger.

 

 

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@Black-Witch Thank you so much for sharing this valuable information. I know that the devs aim for historical accuracy and rely on real-world data to model the sim. Our research shows definitely that there is a huge disparity between the HMG ammo types, and the data you have presented shows that the disparity is not historically accurate. 

 

Over to you, devs! 😄

Edited by QB.Creep
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Having read Black-witch's post, I'd call it fair and have an evil laugh with 6x MG131's in the Mustang....or 8 in the jug...that would make the game likeable again for me.

 

Simple update for the devs as well....

Edited by NIK14
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30 minutes ago, QB.Creep said:

the data you have presented shows that the disparity is not historically accurate

 

Mind you, it's not data, it's an opinion that been presented. Just because there's some basic physics in there, doesn't make it data. And as unreasonable has pointed out, this opinion completely excludes actual damage mechanisms.

 

And how this 20 year old stuff is still news to some people (which then draw the same wrong conclusions as other people did 20 years ago) gets increasingly amazing. :)

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2 hours ago, Black-Witch said:

So where should the Browning .50 sit compared to the MG131 and the UB? How many rounds should be needed to cause the damage described above?

Witch

 

 

is there any data that has been used to extrapolate from those figures to calculate the actual energy/damage done from an aircraft against another aircraft?

 

I'm thinking that if a .50 is fired at 890m/s that as soon as it leaves the barrel it is facing not only normal air pressure but also the air pressure caused by a an aircraft forcing its way through the air at 300mp or at whatever speed it is i.e. it hits a wall of air.  Then it takes a split second to reach the target, during which time it is losing velocity/energy.  Then when it hits it is hitting a target that might be travelling at 300mph (134m/s) so the actual impact speed might be a lot less that 890m/s.

 

(I've also assumed higher retained energy/velocity when both aircraft are slower, when fired against a target with a lower speed, or where the firing aircraft is going a lot faster than the target.)

 

I'm thinking this is more relevant to AP/ball rounds and I'd love to know what actual velocity/energy the rounds would be impacting with and how that might effect what people are experiencing.

 

von Tom 

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Just now, von_Tom said:

 

I'm thinking this is more relevant to AP/ball rounds and I'd love to know what actual velocity/energy the rounds would be impacting with and how that might effect what people are experiencing.

 

von Tom 

 

You can find impact energies if you use a ballistics calculator. I like this one: it has a .50 cal ball preset, but you can adjust all the numbers.

 

http://www.shooterscalculator.com

 

You can adjust for air density, wind speed and direction etc and see the impact velocity and KE for various round types at range.

 

In practice, for .50 cal rounds at the sorts of ranges people usually shoot at in the game - 300m or so - it makes relatively little difference, as the flight time is so short. With lighter, slower rounds and longer ranges the effects of flight time are much more obvious.   

 

AFAIK the game's modelling of ballistics is remarkably good for a program that has to model multiple rounds in the air at time.  It is obviously simplified, but the basic energy and drag outcomes look OK to me.  I do not think there is anything significantly wrong with the model up to the point a bullet hits. It is what happens afterwards that gets tricky. 

Edited by unreasonable
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1 hour ago, JtD said:

 

Mind you, it's not data, it's an opinion that been presented. Just because there's some basic physics in there, doesn't make it data. And as unreasonable has pointed out, this opinion completely excludes actual damage mechanisms.

 

And how this 20 year old stuff is still news to some people (which then draw the same wrong conclusions as other people did 20 years ago) gets increasingly amazing. :)

 

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. 

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There certainly is a problem, quite obvsiously so. Bringing up a simple, 20 year old internet source however is, at best, not helpful in this case. Realistic historical test reports as well as empirical data has been posted on this forum over the years, some of it several times. It gives a much better idea of what to expect than an internet page that states "the damage is 4".

 

QB.Shallot has done a great job with providing some numbers for the current in game situation, and that's essentially what we can take away from this topic.

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51 minutes ago, 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. 

 

2 hours ago, QB.Creep said:

@Black-Witch Thank you so much for sharing this valuable information. I know that the devs aim for historical accuracy and rely on real-world data to model the sim. Our research shows definitely that there is a huge disparity between the HMG ammo types, and the data you have presented shows that the disparity is not historically accurate. 

 

Over to you, devs! 😄

 

You're welcome QB.Creep, the guns on the Mustang have been infuriating me for a while and I hope this discussion helps to bring about a resolution.

 

One thing seems clear to me though, all other opinions taken into account, you can see that the .50 should be VERY similar to the UBS and MG131 in the amount of damage it does when you compare calibre, velocity, weight of round and chemical energy.

 

If the .50 varies greatly from the other 2 weapons I'd be very interested to see how.

 

Cheers

 

Witch

 

Edited by Black-Witch
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44 minutes ago, JtD said:

There certainly is a problem, quite obvsiously so. Bringing up a simple, 20 year old internet source however is, at best, not helpful in this case. Realistic historical test reports as well as empirical data has been posted on this forum over the years, some of it several times. It gives a much better idea of what to expect than an internet page that states "the damage is 4".

 

QB.Shallot has done a great job with providing some numbers for the current in game situation, and that's essentially what we can take away from this topic.

 

I'd be surprized if the developer team uses any high tech algorithms for the way the guns work in this GAME. More inclined on your latter view...ie. 20 rounds of M2= damage level 1, whereas the UB and MG131 would be something like 2 rounds = damage level 1

Let's not make this into rocket science.

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

"Damage Model Comments

 

I am aware some of you are not totally satisfied with the current damage model as it pertains to WWI. We recently overhauled our entire damage model for the engine and making further changes to it for WWI will also affect WWII. This requires some thinking and more study, but at this moment I cannot make further changes to just WWI. I see this as a long-term project to somehow change only WWI damage modeling. Even so, there are mixed opinions on this issue. Just because there are some vocal critics out there, does not make the loudest voice correct. As usual, we would need to study the issue further before any more changes are made.

 

And finally, some of you want special ammo like incendiary bullets added. This again is a general wish for the engine that can only come at a later date and would require much work from our engineers and special effects dept. I currently have no ETA on this topic, but we are well aware of the desire to have them. "

 

 

Also its not gun whats problem its type of ammo, why UB or MG131 is so mutch uber and M2 crap is non have historical ammo and one does not have HE in mix. Problem is AP vs HE ammo type and how game sim it, you place only AP ammo in 131 or ub and youll get same crapy performace you have in 0.50, you place mix of AP/HE ammo in M2 and you get normal damages eaqaul to mg131 or ub now.

 

Best is play with airplanes that work, and leve broken ones in hangar

Edited by CountZero
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1 hour ago, NIK14 said:

I'd be surprized if the developer team uses any high tech algorithms for the way the guns work in this GAME. More inclined on your latter view...ie. 20 rounds of M2= damage level 1, whereas the UB and MG131 would be something like 2 rounds = damage level 1

 

Even the original Il-2 is far more complex than that, and that was 20 years ago, on computers from 20 years ago...

 

1 hour ago, NIK14 said:

Let's not make this into rocket science.

 

It certainly is not, it is some aspects of mechanical engineering and some computer programming.

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1 hour ago, CountZero said:

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

If enough players make a big enough stink about it, perhaps this work will get prioritized. Where's the harm in trying? It sounds like you agree that there is a problem, and it isn't costing you time or energy if others are raising these issues Why are you trying so hard to dissuade us from this endeavor?

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15 minutes ago, QB.Creep said:

If enough players make a big enough stink about it, perhaps this work will get prioritized. Where's the harm in trying? It sounds like you agree that there is a problem, and it isn't costing you time or energy if others are raising these issues Why are you trying so hard to dissuade us from this endeavor?

His whole thing is to be a perennial cynic.

FWIW I think this is the best way this has been presented in the forums so far, as you guys have been thorough and professional about it. It can't hurt.

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.

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2 minutes 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.

 

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.

 

And @CountZero Yes it is the ammo types that are busted, but the problem can be most easily demonstrated by comparing the weapons systems. The devs are not stupid, they know the guns they modeled and how. If all 3 of the HMG's just fired AP they would all have miserable performance. The solution is to reduce the discrepancy between the two that's caused by the difference in ammunition. 

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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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