Jump to content

Comparing HMG Damage, and issues with .50 cals


Sublime
 Share

Recommended Posts

Tatata_Time
2 hours ago, unreasonable said:

The zero pilot kills may be because the pilot armour is very effective against fragments from a rear attack. I expect that other angles will give them on occasion

 

Maybe is too early to affirm it but we also could say AP default rounds are very effective with armor plates therefore the PK's could be a direct consequence of their main effectiveness, but as I said maybe.

Link to comment
Share on other sites

Yak_Panther

If we look at the 70 degree ricochet figure 2-34 pg 63/49 from the AGARD report. You can determine that the ricochet is a result of the impact velocity not impact angle alone. The impact velocity is noted on that sheet of aluminum in the pic, 1100 fps.

1740604393_ScreenShot2021-01-28at4_16_34PM.png.9a16a22969fcc0fbf2cb815379080cd7.png

 

The document gives the formula to compute the critical velocity to perforate plates at varying degrees of obliquity. Page 51/ 37. It’s the ballistic limit formula used throughout the terminal ballistics.

V50 = {C [Pc (Density of core)* t (Target Thickness)*Ap(presented area of projectile);/ W (Weight of the projectile)]^B(Empirical Constant)+K(Empirical Constant)} * Secant of impact angle.

973586072_ScreenShot2021-01-28at5_53_23PM.png.95530fb813b5c9e7bc9046550a633e13.png

 

The ballistic velocity limit for the round and plate used in the 70 degree test, is on page 52 From this we can compute the velocity required to reliably perforate a 70 degree impact on a .09 inch thick plate of 7075-t6. AKA the 70 degree test on page 63.

 

First we determine the ballistic limit for a plate .09 inches thick at zero degrees. Based on the chart for 7.62 AP on page 52.

454172157_ScreenShot2021-01-28at4_42_50PM.png.85ec233e9fa9e80102fd0e8316edee78.png

 

The velocity need to perforate a plate of .09  (10^-1.04) inches thick, with 0 degrees of obliquity, is about 10^2.8 or 630.95 feet per second. To have a 50/50 chance of penetrating a .09 inch thick piece of plate impacting head on. The 30 cal 7.62 mm AP round has to be moving at more than 630.95 feet per second. Is what this formula is saying.  

 

We can then use the formula provided by the author to compute the critical velocity at any other impact angle. All we have to due is, multiply the zero obliquity critical impact velocity by the secant of angle impact. As noted on page 51.

 

We want to know the critical velocity for 7.62 AP round impacting at 70 degrees.
The secant of 70 degrees is 2.92  

1823.37 = 630.957 * 2.92

Hence, the velocity needed for that shell to perforate a .09 inch plate of 7075-t6 at an angle of incidents of 70 degrees is 630.957 * 2.92 or ~ 1842.37 fps.

 

 

The 70 degree test occurred at velocity of 1100 fps, 700 fps below the critical velocity. The ricochet is a result of the impact velocity, not the angle of impact. This is proven elsewhere in that document.

 

Figure 2-25 page 57 /43 shows ricochets occurring when the round impact at 925 fpm on a piece of 7075-t6 sloped at 60 degrees. While not ricocheting at the same angle when velocity is above the  critical velocity.  Which is exactly what  is predicted by the critical velocity function it says the rounds need to impacting above 1200 fps to not ricochet.

The secant of 60 degrees is 2

630.956 * 2 = 1261.9 Fps needed to not ricochet.

 

 

1872056763_ScreenShot2021-01-28at4_49_05PM.png.11f5f57849dfa3ad6fca43546563ee3b.png

 

Figure 2-35 page 64/50 We see measured amounts of damage for 2000 fps shots at impact at almost 80 degrees.

650628955_ScreenShot2021-01-28at4_52_36PM.png.5c0cbb5afce2fb85fc9152934e68f31a.png

 

The velocity limit for oblique impacts on pages 51-54/36-40 are computed. In same manner as our check on the 70 degree .09 thick plate. EG, V50 * sec of impact angle

To determine the velocity needed to achieve V50/ at various obliquities for those rounds The authors are taking V/50 and * the secant of the obliquity angle and graphing them. The reasons they don’t display impacts above 60 degrees is editorial not a comment on the rounds effectiveness at angles above 60 degrees.  

 

1135051439_ScreenShot2021-01-28at4_21_06PM.png.874e3931b1dfa3d4651ccbc2ab032f74.png

 

Using the same methodology in the AGAR report, It’s possible to compute the critical velocity required for any obliquity of the weapons presented.

 

For the 12.7 mm API projectile to have 50 / 50 chance of penetrating a 1 inch  356-t6 plate it has to be moving at ~ 1000 feet per second. If the plate is angle at 60 degrees what is the critical velocity?

 

Since the secant of 60 degrees is 2.  The critical velocity is 2000 feet per second or 10^3.3 feet per second. Which also shows good agreement with the chart.

 843354324_ScreenShot2021-01-28at4_22_22PM.png.f15420dfe68617f58ac5e12d70c87823.png
Based on the ballistic velocity to range  table on page 18/4,  a 12.7 API round would be above the critical velocity and perforate a 1 inch thick sheet of 356-t6 angled at 60 degrees out to 500 yards.  

235810597_ScreenShot2021-01-28at4_14_37PM.png.49d762a315a26cad6c195a4188fac88b.png

 

Lets look at a  2mm / .07 inch plate. That's a reasonable thickness for a ww2 aircraft plate,

 

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjcy576z7juAhWSKn0KHVo3AsAQFjABegQIAhAC&url=https%3A%2F%2Fwww.mdpi.com%2F2571-9408%2F2%2F4%2F172%2Fpdf&usg=AOvVaw1ti2B97X6dpzKSfEVIwC0-

 

What would be the largest angle a 12.7mm API flying at 2000 fps could penetrate a 2mm thick plate of 356-T6?

We just need to do a bit of algebra.

2000 fps(The required penetration velocity) = 316 (critical velocity of zero degree plate. 07 inch plate) * sec of the impact angle

2000 = 316 * 6.32 = 80.89 degrees

The inverse sec of 6.32 is 80.89 degrees.

 When the 12.7mm round traveling at 2000 fps impacts a 2mm (.07 inch) at angles above 80.89 degrees on we’re likely to see mostly ricochets.

However, those ricochets are still likely to cause material damage to the aircraft. As a result of the low yield strength of aluminum.

263186224_ScreenShot2021-01-28at5_02_18PM.png.fe2c1aff63a35df352ba8293bef4a790.png

https://apps.dtic.mil/dtic/tr/fulltext/u2/274128.pdf

 

Thick blocks of aluminum show significant deformation from ricocheting hits from 12.7 rounds, because of the high ductility of aluminum. Even at smaller rounds at lower velocities against comparable plate thickness still significantly deform the plate.

 

518365513_ScreenShot2021-01-28at5_07_16PM.png.4e63578927aef37a265c0d8af0551aaf.png


When the penetrator diameter is greater than thickness of the plate. The plate is stretched a greater distance per inch of penetration.  Think of a right triangle,. A^2 + B+^2 =C^2. As the projectile diameter (A^2) increases, the distance the plate is deformed (C^2) increases.

 

The larger the diameter projectile, the greater strain on the plate material. As force = work / distance. Which is why the critical velocity (for a penetration) drops as the ratio of plate thickness to projectile thick decreases. Eg as the ratio of plate thickness goes to shell diameter goes from 1/1 (plate thickness / projectile diameter) to 1/4. Eg 1 to .25 the critical velocity drops. As the force required to penetrate is function of ratio of the plate thickness to projectile diameter. Which is why it's accounted for in the V50 formula provided by the AGARD authors.  It takes less energy for a overmatched shell to perforate a plate.

 

454192434_ScreenShot2021-01-28at6_48_24PM.thumb.png.4052c3abab8bfed3dfc8fa772afee264.png

 

Overmatch is critical in the determination of a ricochet. As the critical velocity drops as ratio shell diameter to plate thickness increases.

 

The number of ricochets exhibited don’t seem reasonable. Given that  12.7 mm projectile traveling at 2000 feet per second has to impact above 80 degrees, near parallel, in order to ricochet. The number of ricochets is why it takes so many rounds to change the damage states

 

I wonder if their ricochet model is tuned for rolled hard armor? Given the difference in material properties, the critical angle for RHA is much lower than aluminum. Either that or the damage per ricochet is to low.

263186224_ScreenShot2021-01-28at5_02_18PM.png.fe2c1aff63a35df352ba8293bef4a790.png

I’d get into the damage model presented in AGAR but this all ready a tome. Suffice to say, I don’t think the armor plate is the issue. You can remove it in the 110 G2, and the amount of pilot kills and damage taken is the about the same with it.  

 

 

 

Screen Shot 2021-01-28 at 4.14.37 PM.png

Screen Shot 2021-01-28 at 4.21.06 PM.png

Edited by Yak_Panther
double images.
  • Upvote 7
Link to comment
Share on other sites

unreasonable

A good explanation: just one question to clarify: is the critical velocity the velocity at which none/all of the round will ricochet, or 50% of them? I am not quite clear from your text.

 

I am glad that you agree with my original point that you cannot rule ricochets out just by looking at round diameter and skin thickness alone. No-one, to the best of my knowledge, has ever said that they are the result of impact angle alone, either. They were the result of the impact angle in that test, as that was the variable quantity.

 

Very high angles - common when planes are firing from dead six and hitting wing surfaces - will cause ricochets even with .50 cals by this formula, as the secant of the angle approaches infinity. 

 

In my own tests ricochets look rare except at very high obliquity, although I have never set out to count them, which may be worth doing. So I am not sure if they look too frequent or not.

 

 

 

Link to comment
Share on other sites

Yak_Panther

 

On 1/25/2021 at 5:33 AM, unreasonable said:

 

We may have been referring to different sheets: here we go: text on left clearly states 0.090 inch sheet vs .30 cal bullet, text on right states that ricochets start as you increase from 60-70 degrees.

 

While it is obvious that the ratio of projectile diameter to target thickness is a relevant variable, you cannot credibly assert that "over match" regarding this alone makes ricochets impossible, or even unlikely, irrespective of the impact velocity and angle.  It is also pure conjecture that rounds that ricochet in the game are not in fact doing any damage.  So this whole ricochet business is just a red herring.

 

 

 

 

1 hour ago, unreasonable said:


I am glad that you agree with my original point that you cannot rule ricochets out just by looking at round diameter and skin thickness

alone.

Literally never said that.

 

On 1/24/2021 at 9:51 PM, Yak_Panther said:

An AP round impacting aircraft aluminum obliquely with a reasonable velocity should not ricochet.

 

 

1 hour ago, unreasonable said:

Very high angles - common when planes are firing from dead six and hitting wing surfaces - will cause ricochets even with .50 cals by this formula, as the secant of the angle approaches infinity.

WW2 aircraft wings are cambered. Even during level flight the angle of attack is greater than 1 degree, So the chances of rounds impact at 90 degrees are not very common.1813762453_ScreenShot2021-01-28at9_28_13PM.png.22b0642cb566fbcf2a08dbe119063767.png

Screen Shot 2021-01-28 at 9.28.13 PM.png

  • Upvote 1
Link to comment
Share on other sites

unreasonable

Some proportion of rounds fired from the rear will land at obliquity between 75 degrees and 90 degrees.  Ricochets from aircraft skin are possible at high angles, even at high velocities. 

 

Again taking your 7.62 mm example and recalculating:

 

0 degrees -      631  fps 

60 degrees - 1,262 fps

70 degrees - 1,845 fps

80 degrees - 3,636 fps  (MV for a typical 7.62 mm MG is 2,800 fps (M60))

85 degrees - 7,240 fps  (is this velocity "reasonable"?)

etc  This, BTW, is why the higher obliquity lines are not shown in the graphs.

 

The question of whether they are too common in BoX cannot be answered by eyeballing videos in which the hits and ricochets are not even counted, let alone the angles measured.  Perhaps they are too common: so do some proper testing where you can fix and measure the variables and prove it.   

 

 

Link to comment
Share on other sites

You cannot just increase projectile speed at high angles of obliquity based on a fixed formula to assure the projectile eventually penetrates. There is no generally valid function to assure that, it depends on too many things. No two projectiles and no two armours are the same. Think of it - the secant just accounts for the 0° projectile velocity compound of the projectile speed. The formula totally ignores the finer (and even some of the basic) points of high obliquity armour penetration. Don't use it for purposes it wasn't intended for.

 

If you look at reliable AP data of guns, you don't get a formula, but you get a full set of data either a tabular or graphical form, which is based on gun, projectile and armour type. From emperical tests, with a little bit of interpolation. Hardly ever there is an extrapolation, let alone a simple one.

 

There's also a reason these charts typically end at 60-70°, because beyond this point uncertainty gets very high, even if (big if) the necessary projectile velocities are still obtainable.

 

WRT angle of impact, if you take a typical WW2 airfoil with say 14% maximum thickness reached at 30% behind the leading edge of the wing, you taper 7% thickness (half of 14° if you were perfectly symmetrical behind the wing) over 70% length, for a ratio of 1/10 or an angle of about 6°. Which is the minimum.

If you're not perfectly symmetrical, it gets better: If you're above, the angle for the upper side gets better and the upper side gets more likely to be hit, whereas the lower side presents you even worse angles, but naturally starts to disappear from your field of fire. Obviously, you can't shoot the lower side from above.

Edited by JtD
  • Upvote 3
Link to comment
Share on other sites

unreasonable
1 hour ago, JtD said:

You cannot just increase projectile speed at high angles of obliquity based on a fixed formula to assure the projectile eventually penetrates.

 

Yak_Panther is not even doing that: as far as I can see, in among the obfuscation, he is using a formula that he thinks gives a velocity at which there is a 50% p of ricochet: to claim that ricochets cannot happen above that velocity!

 

It is all too absurd. The developers have said over and over again, if you want to dispute the FM or DM you can, but you have to produce some repeatable track or test in SP and a reference document that shows a discrepancy.

 

What we get here, as in most of these threads, is people saying, no, the developers is wrong, we have to have MP tests! No need for documents, we have common sense! And since there are 100 players who think this is wrong, this means that it is 100 times more likely to be wrong!

 

I have seen more logical and reasoned discussion in a D&D debate about whether elves have pubic hair.    

Edited by unreasonable
  • Sad 1
  • Upvote 3
Link to comment
Share on other sites

Just found this in Terminal Ballistic Data Volume III (a series which I recommend to anyone who is interested in performance of US weapons):

 

image.thumb.png.17f5f42e0beac1138e8a2dae65bbcaca.png

 

It's ike 70 years old, but feel free to validate some of the algorithms against it. Keep in mind it only goes up to 70°. Fwiw, 0.50 AP ammunition has a cone angle of about 30°, which means that hits at obliquities beyond 75° will happen with the flange of the projectile, not the nose, which completely changes penetration behaviour (in that it gets a lot worse).

 

@unreasonable - I think Y_P is saying richochets don't have to happen, penetration may occur.

Link to comment
Share on other sites

unreasonable
41 minutes ago, JtD said:

 

 

@unreasonable - I think Y_P is saying richochets don't have to happen, penetration may occur.

 

Of course he knows that ricochets are possible, but at what velocity and angle? He says, "An AP round impacting aircraft aluminum obliquely with a reasonable velocity should not ricochet."

 

I fully accept your point that it is all very complex: that was my point all along. But if the formula he chooses to use to make his points shows that ricochets at angles from some rounds from rear attacks are 50% probable at velocities that exceed the MV of the gun under discussion, what proportion are they likely to be at "reasonable" velocities? Whatever those are.

 

If someone can construct a reasoned case for why the proportion of ricochets in game is too high (or too low, perhaps for HE rounds), I have no problems with that. What I see here is just another person seizing on  a piece of information, (from TacView!), without analysis, and out of context. Childish responses that not many hits are at 90 degrees are not likely to improve my opinion of his analysis or motivations.

Edited by unreasonable
Link to comment
Share on other sites

HR_Zunzun
1 hour ago, unreasonable said:

What we get here, as in most of these threads, is people saying, no, the developers is wrong, we have to have MP tests! No need for documents, we have common sense! And since there are 100 players who think this is wrong, this means that it is 100 times more likely to be wrong!

 

I have seen more logical and reasoned discussion in a D&D debate about whether elves have pubic hair.    

 

No, what this people have been trying to convey is that current situation with planes flying unaffected after being hit by more than 50 0.5ap rounds doesn´t seems plausible.

You cannont ask for a 100% perfect test because in DM basically doesn´t exist. There are too many variables to consider when a plane is shooting at another at 300mph. You are going to introduce some degree of interpretation no matter how many test and reports you consider.

But again, since the beginning what have been trying to prove is that the current situation regarding aerodinamic effect doesn´t seems plausbile. And I think that the last two post with test have very much proved it.

  • Upvote 3
Link to comment
Share on other sites

[DBS]Browning
1 hour ago, HR_Zunzun said:

 

No, what this people have been trying to convey is that current situation with planes flying unaffected after being hit by more than 50 0.5ap rounds

 

This isn't the current situation.

Whatever your stance on the issue, it is disingenuous to claim that 50ap rounds leave planes flying unaffected. There is an effect, even if you think it's not enough of an effect.

  • Sad 1
Link to comment
Share on other sites

HR_Zunzun
24 minutes ago, [DBS]Browning said:

 

This isn't the current situation.

Whatever your stance on the issue, it is disingenuous to claim that 50ap rounds leave planes flying unaffected. There is an effect, even if you think it's not enough of an effect.

 

Well, I would have said almost unaffected. Or not plausibly affected. I said unaffected because combat wise that was the result.

The tests were perfectly clear in this and that was the main purpose of this post. Then it have derailed when some people asked for proof they know nobody (no even devs) will be able to provide.

  • Upvote 1
Link to comment
Share on other sites

Tatata_Time
38 minutes ago, [DBS]Browning said:

This isn't the current situation.

Whatever your stance on the issue, it is disingenuous to claim that 50ap rounds leave planes flying unaffected. There is an effect, even if you think it's not enough of an effect.

 

After almost ten months and several threats & post talking about this and you're still in the negation phase. To update yourself on this is all about first you should admit there's an issue with the 50's in this game. Maybe the AP inflicted damage  is well recreated in the parts/hitboxes  they impact ( I'm still not 100% sure of it), but 0.50 cal type of bullets got a very  unnacurate representation in this game, that generates an artificial disadvantage for those A/C that equipped them also an artifical advantage for their opponents. This is what most people (people who normally fly/play this game) affirm after played, then come here and try to explain (some of them with technical data, some of them with their own ingame experience) their ingame experiences. 

In the case it only affected P-40 it would be almost anecdotal, but 0.50 cal MG's are everywhere in BoBp and in the incoming BoN: Spitfire MK.IX with D wing, P-47 D-28 & D-22, P-38J, P-51D & incoming B version with only 4 MGs, A-20's & B-25 for deffensive purpouses,.... A great part of those disingenuos still thinking that 50 rounds were enough to dissable opponents in a recent past. I can understand new DM "tends" to be more accurate than before, but nowadays is creating a big gap between contemporaries contenders in late war.  

  • Upvote 1
Link to comment
Share on other sites

 

55 minutes ago, HR_Zunzun said:

Then it have derailed when some people asked for proof they know nobody (no even devs) will be able to provide.

 

Well, from the data presented and more so from the data linked in this topic you can derive a pretty realistic expectation wrt to the type of damage a 0.50 round will cause on a sheet of metal. It can also give you a fairly good expectation wrt to damage to a wing. There's still bit of an argument about what happens at shallow angles of impact, but this is an issue that in practice is dominated by randomness to a large degree and will not be solved until someone fires a statistically relevant number of 0.50ies at the wings of the aircraft in question, preferably mid-air under various flight conditions.


So all that's left is to find some aerodynamic data (maybe here) from what holes in the wing, or in a plate for that matter, actually do. Unless you want to do some theoretical stuff, which is also possible with a reasonable accuracy, but quite labour intensive.

 

So I don't think it was a derailment, it was a valuable educational detour.

 

When it's completed, further in game testing can quantify the bug and then we're where we need to be, eventually.

Edited by JtD
Link to comment
Share on other sites

[DBS]Browning
1 hour ago, [DBS]Browning said:

Whatever your stance on the issue, it is disingenuous to claim that 50ap rounds leave planes flying unaffected. There is an effect, even if you think it's not enough of an effect.

 

6 minutes ago, Tatata_Time said:

After almost ten months and several threats & post talking about this and you're still in the negation phase. To update yourself on this is all about first you should admit there's an issue with the 50's in this game. 

 

I absolutely think there is room for improvement in weapon damage models. All I intended to say with my post is that it isn't true that 50 rounds of .50 leave targets "unaffected".

 

Link to comment
Share on other sites

HR_Zunzun
1 minute ago, JtD said:

 

 

Well, from the data presented and more so from the data linked in this topic you can derive a pretty realistic expectation wrt to the type of damage a 0.50 round will cause on a sheet of metal. It can also give you a fairly good expectation wrt to damage to a wing. There's still bit of an argument about what happens at shallow angles of impact, but this is an issue that in practice is dominated by randomness to a large degree and will not be solved until someone fires a statistically relevant number of 0.50ies at the wings of the aircraft in question, preferably mid-air under various flight conditions.

So all that's left is to find some aerodynamic data from what holes in the wing, or in a plate for that matter, actually do. Unless you want to do some theoretical stuff, which is also possible with a reasonable accuracy, but quite labour intensive.

 

So I don't think it was a derailment, it was a valuable educational detour.

 

When it's completed, further in game testing can quantify the bug and then we're where we need to be, eventually.

 

And as I said in my previous post, those test don´t tell the whole history. For example, they don´t take into account the adding effect of multiple impacts over a limited area, nor the take into account the effect of aerodynamic forces of a plane traveling at 300mph into damaged skin. Or how it would affect a bullet (or several bullets) tumbling before exisiting.

That´s why that if a plane is hit by 50+ 0.5 bullets in the game and we don´t observed a combat effectiveness reduction with regard to aerodynamical effect doesn´t seem plauisible to me or many other people that have been happily deprecated.

  • Upvote 1
Link to comment
Share on other sites

No test data ever will tell the whole story. I don't really know what you're expecting. You'll always need to apply what you've learned to the particular scenario you're interested in, and that's possible.

 

Anyways, to gauge expectations, the difference in lift, drag  and moment coefficients of an A-4 in clean condition and after having been hit by a 25mm HE round. So drag, yes; lift, no; moment, only along the roll axis. Stall got bad, too.

Not comparable to a Bf109 hit by a few 0.50 rounds, but it already shows that you can't expect miracles.

 

image.png.787a485bbfc4f3b11b4ebaa1be78742b.png

 

image.thumb.png.3a8cc5456be73f9bf87d5ae9fe7e8a34.png

image.thumb.png.c20bd68790904ee064f71dc407690fd7.png

Edited by JtD
  • Upvote 1
Link to comment
Share on other sites

sniperton

What we can plainly claim (and I guess most of us are in agreement in this respect):

1. Allied .50cals are misrepresented in game with inadequate ammunition. [fact]

2. These misrepresented .50cals do significantly less (aero) damage than other board guns with similar caliber, but different ammo. [demonstrated multiple times]

 

So I think there's no need for "further in game testing" on our side. It is not our task "to quantify the bug", it's the duty of the devs to remedy an obvious inadequacy and imbalance more or less frustrating a bunch of players. Human patience is a merit, but a limited one.

  • Thanks 2
  • Upvote 2
Link to comment
Share on other sites

=EXPEND=13SchwarzeHand

@JtD´s post should also raise the point, that the argument seems to always go into the direction of .50s doing way too little, while totally leaving out the option of 13mm and the Russian equivalent just doing way too much aerodynamic damage. Thats always a problem with mainly comparative tests.

  • Upvote 2
Link to comment
Share on other sites

unreasonable

@JtD

There are also a couple of fairly recent studies on the web of the effects of 20% of chord round holes on an airfoil: one on wind tunnel tests, the other a computer model' looking at the before and after measurements, depending on the hole orientation. You may have seen them: anyway no doubt you can make more sense of these than I can. Managed to download these:

 

https://figshare.com/articles/conference_contribution/The_influence_of_hole_orientation_on_the_aerodynamics_of_battle_damaged_wings/9221714

https://www.scielo.br/scielo.php?script=sci_arttext&pid=S2175-91462020000100338

 

 

 

 

  • Upvote 1
Link to comment
Share on other sites

HR_Zunzun
37 minutes ago, JtD said:

Anyways, to gauge expectations, the difference in lift, drag  and moment coefficients of an A-4 in clean condition and after having been hit by a 25mm HE round. So drag, yes; lift, no; moment, only along the roll axis. Stall got bad, too.

Not comparable to a Bf109 hit by a few 0.50 rounds, but it already shows that you can't expect miracles.

 

Only that have been clearly stated so many times that the complain is not about hitting with just a few 0.50 rounds. It have been talked about 50+ rounds. And lack of drag is the thing that have been complained the most. So, miracles? No, but some plausibility.

  • Thanks 1
Link to comment
Share on other sites

21 minutes ago, HR_Zunzun said:

Only that have been clearly stated so many times that the complain is not about hitting with just a few 0.50 rounds. It have been talked about 50+ rounds.

 

Only that the DM isn't OK for 49- rounds, either. So what's your problem? Personally I am more interested in what a few rounds of 0.50 do because that's more relevant for a proper damage model on the bottom line. To each his own, I guess.

Link to comment
Share on other sites

Agree with ZunZun...

 

And personally I'll stay offline, shooting my modified 50 cals (with MG131 specs) until the developers do something about the 50 cal issue, I will also keep my wallet closed for any other products.

Let me tell you though...it's so enjoyable...hardly any PK's but man them 109's and 190's go down in drowes and do they ever limp once clobbered? They can hardly stay airborne after a little squirt! MG131 FTW!

Guess I finally "got gud" at shooting with them 50 cal's lol!

Link to comment
Share on other sites

56 minutes ago, =EXPEND=13SchwarzeHand said:

@JtD´s post should also raise the point, that the argument seems to always go into the direction of .50s doing way too little, while totally leaving out the option of 13mm and the Russian equivalent just doing way too much aerodynamic damage. Thats always a problem with mainly comparative tests.

I can't speak for what others say in the discussions here, but all of the communication that I have had a hand in crafting has said simply that there is a problem and something needs to be done to account for it (either buff AP or nerf HE).

 

Look at the original bolded text in the conclusion section of the first post in the thread: 

Quote

An exact solution will not be proposed here, as we have intentionally excluded some factors for testing purposes. However, this data undeniably demonstrates the inherent weakness in the current state on the Browning M2, as well as the over-modeling of low yield HE weapons. It is our hope that the dev team will take this information and continue to improve upon this simulation.

 

And look at the language in this poll:

I think it is important to leave the details regarding how to address the issue up to 1C/777. They are more than capable of solving the issue on their own.

  • Like 1
  • Upvote 3
Link to comment
Share on other sites

HR_Zunzun
11 minutes ago, JtD said:

 

Only that the DM isn't OK for 49- rounds, either. So what's your problem? Personally I am more interested in what a few rounds of 0.50 do because that's more relevant for a proper damage model on the bottom line. To each his own, I guess.

 

Noting the effect with 50+ was to prove one extreme situation.  One, that unfortunately, have been experience by many while playing the game. I think is not that difficult to understand.

If you can´t agree that losing negligible amount of speed after being hit more than fifity times is important then I can´t understand your concern about the DM.

Link to comment
Share on other sites

 

24 minutes ago, HR_Zunzun said:

If you can´t agree that losing negligible amount of speed after being hit more than fifity times is important then I can´t understand your concern about the DM.

 

How do you get that idea? I'm interested in finding out how much loss of speed is a realistic expectation. I just don't care if it is for the one example you appear to claim to be the only relevant one, or any other number of hits.

 

Speaking about how much, a 20" diameter jagged hole increases cd of a 24m² reference area by about 0.002, a plain one about 0.001. One on top, the other one on the bottom of the wing. Or about 10%-15% drag for a German WW2 fighter in high speed config. Speed loss about 5%-7%. In terms of damaged area about 400 times of what you can expect for a 0.50 (1 inch diameter holes assumed, one clean top, one jagged bottom). Just going with these figures, 50 holes are good for about 1% speed loss. So instead of 600, you'd be doing 594. Add to that some specific/random failures regarding blown off panels, covers and so on, you'll get somewhere realistic. Just as a first ball park from my side.

Edited by JtD
  • Upvote 2
Link to comment
Share on other sites

29 minutes ago, JtD said:

terms of damaged area about 400 times of what you can expect for a 0.50 (1 inch diameter holes assumed, one clean top, one jagged bottom). Just going with these figures, 50 holes are good for about 1% speed loss. So instead of 600, you'd be doing 594. Add to that some specific/random failures regarding blown off panels, covers and so on, you'll get somewhere realistic. Just as a first ball park from my side.

The report shows that at larger angles that you would expect shooting at position behind an aircraft, you are likely to get entry holes significantly larger than 1 inch and due to the velocity loss associated with travelling through the material, even larger holes exiting can be expected.

By no means is a. 50 comparable to a cannon round. But your suggestion that it would take 400 rounds to be comparable to a single cannon hit has been proven false by the sources in this thread.

Link to comment
Share on other sites

There's about a dozen reports floating around in the topic by now. Which one are you referring to? The design manual for impact damage tolerant aircraft structure? Feel free to adjust the hole size a figure you find more suitable. 2 inches? 50 holes - about 580 km/h. Just keep in mind that it's not the maximum damage size (i.e. cracks), but the hole size. Feel free to go through the sources and come up with your very own ballpark.

 

There's nothing wrong with assuming 1 inch diameter, it's totally within the ranges given. Maybe not when fired at from directly behind, but then there'd be no exit hole on the bottom of the wing either. So that cannot have been the scenario I was referring to, can it. I also think that putting 400 holes in a wing without shooting any panels and such off is extremely unlikely. You're more likely to shoot the entire wing off. However, if you managed, I doubt the aerodynamic impact would be a lot larger than what the numbers are suggesting.

 

For what it's worth, the 400 hits weren't compared with a cannon hit, but a 20" (jagged) hole. But now that you mention it, the 25mm hit is similar in drag effect, the 30mm hit however does a lot less, about half the drag penalty of that 25mm hit or that of that 20" jagged hole.

  • Upvote 1
Link to comment
Share on other sites

HR_Zunzun
2 hours ago, JtD said:

 

 

How do you get that idea? I'm interested in finding out how much loss of speed is a realistic expectation. I just don't care if it is for the one example you appear to claim to be the only relevant one, or any other number of hits.

 

Speaking about how much, a 20" diameter jagged hole increases cd of a 24m² reference area by about 0.002, a plain one about 0.001. One on top, the other one on the bottom of the wing. Or about 10%-15% drag for a German WW2 fighter in high speed config. Speed loss about 5%-7%. In terms of damaged area about 400 times of what you can expect for a 0.50 (1 inch diameter holes assumed, one clean top, one jagged bottom). Just going with these figures, 50 holes are good for about 1% speed loss. So instead of 600, you'd be doing 594. Add to that some specific/random failures regarding blown off panels, covers and so on, you'll get somewhere realistic. Just as a first ball park from my side.

I got the idea from your previous posts. You were the one that said that talking about the extremes is not important. But anyway, that is not really important.

That 50 0.5 impacts are going to cause a speed reduction of only 6kph when just by sealing gaps they could improve the speed by a bigger margin is  no logical.

 

By the way. Another example of what 0.5 could do to aircraft skin. He didn´t report the ammo used but by the date (Donald Bryan 352nd 10/04/44) I would assume it was API. Note that he didn´t report any fire or explosion.

997629186_Damagetofuselage.png.68657c92589a70bc01c1148a27cf6f2a.png

Edited by HR_Zunzun
Link to comment
Share on other sites

I'm more confused than anything.

5 hours ago, JtD said:

There's nothing wrong with assuming 1 inch diameter,

So the lower limit can be applied to all 200 rounds now (assuming a 2 inch hole now). We can be happy with that then. The upper limits are clearly outliers as well but why apply the lowest with the same principle?

 

5 hours ago, JtD said:

Maybe not when fired at from directly behind, but then there'd be no exit hole on the bottom of the wing either

So firing a round into the back of the wing would not mean you'd end up with a large exit hole at the front or wherever it chooses to deflect to? We have no evidence to suggest that lower velocity rounds after penetration would cause skin damage?

 

 

Link to comment
Share on other sites

unreasonable

I think the point about AP shots hitting directly from the rear is that, if they go straight, they might have to pass through a rear spar, whatever is between the spars such as landing gear or ammunition trays, landing lights and gun cameras, wing mounted weapons, as well as various support struts, then the main spar, so a proportion will not make an exit hole at all. Obviously depends on the wing.

 

At least JtD is trying to estimate what sort of speed loss is actually reasonable for a number and size of holes. Hard to say which side(s) of the ratio in question are in need of adjustment unless you can do that. 

Link to comment
Share on other sites

QB.Shallot

@unreasonable

Once again, there's not much left to determine. What you're proposing would mean .50's should be more effective at structural damage since all the kinetic energy would be transferred to the airframe, and its currently 25% less effective than the MG131's in that department. 

 

Alternatively, the round would tumble or fragment, causing a larger exit gash. And as we've already determined, the entry wound from a rear aspect shot would be more gash like as well due to the angle of impact. The speed penalty from 60+ .50 AP rounds is minimal, ranging from 1-3MPH. One more time 1-3MPH Speed Penalty from over 60 M2 .50 rounds in the wing, passing through the rear, and exiting at the leading edge. 

 

@Barnacles Makes a pretty clear point that the basic tidying up of an airframe will yield speed benefits over 6x greater than the speed penalty of getting lit up like a Christmas tree with American HMG's. (linked here)

 

 

You have been saying a lot, and I don't really understand what you're trying to yield with all your textual exertion. 

We can argue over the minutiae, but I'm in the 'lets just acknowledge the problem and go home' camp. 

Edited by QB.Shallot
  • Like 1
  • Thanks 1
  • Upvote 4
Link to comment
Share on other sites

unreasonable
Just now, QB.Shallot said:

@unreasonable

Once again, there's not much left to determine.

 

You have been saying a lot, and I don't really understand what you're trying to yield with all your textual exertion. 

We can argue over the minutiae, but I'm in the 'lets just acknowledge the problem and go home' camp. 

 

I am not "proposing" anything: I am stating why not all AP hits to wings would produce exit holes. 

 

Common sense is a poor guide to physics. If it were not, no-one would need STEM degrees.  What is left to determine is some quantification of real world aerodynamic penalties from various levels and types of damage. 

 

You have made your case, but you cannot expect other people not to want to try to find additional evidence and discuss this further, if they are not yet satisfied that the evidence of real world effects supports the view that the aero damage from .50 cal AP should be substantially increased.  The problem as I see it is that this evidence has yet to be produced.

 

The reason this issue bothers me enough to spend time on "textual exertions", is that I have already had one of my favourite games (RoF) substantially ruined, after the developers caved in to an intense spell of lobbying from MP players, concerned about balance between planes in MP dogfights, leading to some frankly silly changes. I do not want to see the same thing here.

 

I would rather SP and MP games had different DMs. The developers could put in their best estimate for SP - as they do now - and in MP you could decide by polls or however you want to adjust the SP DM for effects of packet drop, or game balance, or whatever you want, until you are satisfied. Then we could all "go home".    

Edited by unreasonable
  • Like 1
  • Upvote 1
Link to comment
Share on other sites

2 hours ago, QB.Shallot said:

I'm in the 'lets just acknowledge the problem and go home' camp

 

I'm in the 'lets acknowledge a problem and investigate further' camp. For two reasons.

 

One, I find all this very interesting.

 

Two, if we can come up with not only the problem, but also a solution or even just a few steps towards a solution, we make it a lot easier for the devs to implement it. Which means a more accurate simulation, sooner, for us.

  • Upvote 2
Link to comment
Share on other sites

QB.Shallot

@JtD I have no qualms with exploring the subject. As I've said, I've learned a lot with the data that many folks have brought to the table, and am looking forward to learning more. My issue lies with some participants role playing as the developers. The devs have demonstrated some remarkable competence in their creations. I think the Current G-Model is a perfect demonstration of their ability to effectively revise changes they've made to be more in line with what practical data provides. 

 

The initial data set that the model was based on was grounded in the context of untrained individuals under load. The new revised model we have now follows a different philosophy as well as a blend of personal experience gathered by Petrovitch. In general, I think the new model has also greatly enhanced the sim and allows maneuvers to be pulled that are more in line with anecdotal accounts. I have absolute confidence in the devs ability to do this again with the DM.

 

Gathering and interpreting data? Absolutely, sign me up. Pretending to be the devs? That's when the discussion turns to self service IMO, and the thread rapidly loses its value. 

  • Like 1
  • Thanks 1
  • Upvote 2
Link to comment
Share on other sites

Mitthrawnuruodo
29 minutes ago, QB.Shallot said:

@JtD I have no qualms with exploring the subject. As I've said, I've learned a lot with the data that many folks have brought to the table, and am looking forward to learning more. My issue lies with some participants role playing as the developers. The devs have demonstrated some remarkable competence in their creations. I think the Current G-Model is a perfect demonstration of their ability to effectively revise changes they've made to be more in line with what practical data provides. 

 

The initial data set that the model was based on was grounded in the context of untrained individuals under load. The new revised model we have now follows a different philosophy as well as a blend of personal experience gathered by Petrovitch. In general, I think the new model has also greatly enhanced the sim and allows maneuvers to be pulled that are more in line with anecdotal accounts. I have absolute confidence in the devs ability to do this again with the DM.

 

Gathering and interpreting data? Absolutely, sign me up. Pretending to be the devs? That's when the discussion turns to self service IMO, and the thread rapidly loses its value. 

 

The pilot physiology was revised partly thanks to detailed proposals by @Floppy_Sock, who is (as far as I understand) not affiliated with the developers. I'm not sure that this is such a good example.

 

At what point does interpreting data and arguing for a particular solution turn into "pretending to be the devs"?

Edited by Mitthrawnuruodo
Link to comment
Share on other sites

unreasonable
4 minutes ago, Mitthrawnuruodo said:

 

 

At what point does interpreting data and arguing for a particular solution turn into "pretending to be the devs"?

 

At the point when the interpretation of the data leads to a solution that is unwanted. But of course you knew that.

 

 

  • Upvote 1
Link to comment
Share on other sites

8 hours ago, unreasonable said:

they might have to pass through a rear spar, whatever is between the spars such as landing gear or ammunition trays, landing lights and gun cameras, wing mounted weapons, as well as various support struts, then the main spar, so a proportion will not make an exit hole at all. Obviously depends on the wing.

But this point has been raised previously. We're going in circles. You're then talking about a .50 round smashing into something and either deflecting or imparting all of it's energy into the object. Both of which will cause additional damage.

 

There needs to be a middle ground. We don't want there to be a best case AP hit every time where it's completely smashing something to bits and causing loads of damage because that's not realistic (we have that with HE hence the complaints). But at the same time, the argument that it's going to be a small entry hole at best isn't true either.

 

We need it to be scalable, where the 4x on the 51 B/C are a bit meh but effective, but the 8x on the 47 are pretty devastating. There's plenty of evidence of this in gun cams ( https://streamable.com/krfjtg), it aligns with what's described in the AARs and now we numerous reports and an actual model that proves the damage capabilities of the round against stressed skin.

 

The good news is it seems is that the engine does have the capabilities to take into account impact angle and velocity, and the damage does scale based off of this (shoot .50 at 700m and they do absolutely nothing). So we could use the LATDAM model to calculate a number of cases for different velocities and angles, and then we'd have a spectrum of good and bad hits. 

 

Constantly saying, yes but we don't know 100% for sure, isn't constructive. There are plenty of assumptions in the new G model and that's been an incredible addition to the sim. There's no harm in making assumptions for the DM providing those assumptions are applied across the different weapon platforms.

 

 

 

  • Upvote 3
Link to comment
Share on other sites

unreasonable
Just now, Cass said:

 

 

Constantly saying, yes but we don't know 100% for sure, isn't constructive. There are plenty of assumptions in the new G model and that's been an incredible addition to the sim. There's no harm in making assumptions for the DM providing those assumptions are applied across the different weapon platforms.

 

 

I have never said we cannot do anything because we don't know 100% for sure, I cannot see how you could possibly read that into my comment. The developers don't know 100% for sure: it is not possible.  I give the developers some credit: I assume (and hope) they had some reasonable and systematic system to determine the numbers they plugged in that are generating the results causing all the angst, but it may well have some important error. 

 

The DM as it stands, I think, has to decide if a hit to a wing ricochets, how much skin damage it causes on entry, how much damage, if any, it does to other hit boxes (some virtual), whether it exits and how much skin damage that causes. Then if it exits, the same to another target in the line of fire. All taking into account ballistic and target details. For each hit. 

 

By all means go ahead and make your calculations. I want to know what the real answers are for some specific cases, especially what aerodynamic penalties holes of various kinds cause, since this is the area on which we have the least conclusive information. If you can shed any light on that I am all ears. It is not me trying to shut down further investigation. 

Link to comment
Share on other sites

  • Jason_Williams locked this topic
  • Jason_Williams unlocked, locked, unlocked and locked this topic
  • Jason_Williams unlocked this topic
Guest
This topic is now closed to further replies.
 Share

×
×
  • Create New...