Thoughts on the aerodynamic penalty for .50" cal hits.

[unreasonable]

7 hours ago, KW_1979 said:

 

In the US vulnerability survey, out of 50 shots of .50 API-T taken against B-25s and P-38s (all self sealing tanks) 32% of them resulted in a leak or fire.  That's from single shots on the tank.  They also tested compound or followup shots and while they didn't record leaks, the fire rate on compound shots with .50 API-T was 66%.  That would seem to indicate that a burst of .50 had no problem defeating US self sealing tanks.  @=362nd_FS=RoflSeal posted a different US test from 1943 in another thread, done using German type self sealing tanks and in those tests, M8 API and M20 API-T were averaging 1-2 rounds per tank to start a fire.  Once again, this indicates that .50 had no problem defeating a WW2 era self sealing fuel tank.

 

 

It is not just the fact of fires or leaks that is important but their severity. The report notes that the more likely a round was to cause fires the more severe the fire when they occurred. Ie cannons are better at this.  

 

 

Actually the table for the P-47 gives an estimate for API-T single shot A Kill on the P-47 due to Fuel Tank hits as 0.001  Estimating the visible aspect of the tanks in the test case is tricky, and I cannot work it out from the tables as the relevant columns are illegible, but assuming 5% (the lower the number the better API-T looks), in which case the A Kill SS probability from a hit to the tank was 0.001*100/5 = 0.020   For B Kills that is 0.006 and  0.120  

  

No-one is disputing that a burst of 50 cal that gets multiple hits onto the area of a fullish fuel tank, self sealing or not, is likely to cause leaks, or that hits with API - especially compound hits on leaking areas - are likely to cause fires.  I would expect the good bursts with API to produce more fires, but many of them will be redundant since you will also have hit the pilot or other vital control systems.  In a dogfight, taking snapshots spraying 50 cal with API-T in the mix at one in 3-5, randomly hitting the aircraft, there should be only a small difference to the overall number of fires.

 

edit - Good tests BTW: that 109 result may be an extension of the invulnerable tail hit box? A more side angle would show that.

Edited June 23, 2020 by unreasonable

[Aurora_Stealth]

25 minutes ago, unreasonable said:

 

It is not just the fact of fires or leaks that is important but their severity. The report notes that the more likely a round was to cause fires the more severe the fire when they occurred. Ie cannons are better at this.  

 

 

Actually the table for the P-47 gives an estimate for API-T single shot A Kill on the P-47 due to Fuel Tank hits as 0.001  Estimating the visible aspect of the tanks in the test case is tricky, and I cannot work it out from the tables as the relevant columns are illegible, but assuming 5% (the lower the number the better API-T looks), in which case the A Kill SS probability from a hit to the tank was 0.001*100/5 = 0.020   For B Kills that is 0.006 and  0.120  

  

No-one is disputing that a burst of 50 cal that gets multiple hits onto the area of a fullish fuel tank, self sealing or not, is likely to cause leaks, or that hits with API - especially compound hits on leaking areas - are likely to cause fires.  I would expect the good bursts with API to produce more fires, but many of them will be redundant since you will also have hit the pilot or other vital control systems.  In a dogfight, taking snapshots spraying 50 cal with API-T in the mix at one in 3-5, randomly hitting the aircraft, there should be only a small difference to the overall number of fires.

 

edit - that 109 result may be an extension of the invulnerable tail hit box?

 

Good points, FYI - as stated on some other threads and just to remind people the rear fuselage as a structural element is undetachable for almost all fighters in-game (Bf 109 included) by means of using ammunition, only a collision or damage from contact with the ground will cause failure in structural integrity of the rear fuselage (i.e. detachment) from tailplane. The P-38 and some bombers are exceptions.

 

To reiterate again, the rear fuselage and its lack of detachment from tailplane is not specific to the Bf 109 - it is a universal issue with many aircraft fuselages in-game.

 

I think most agree the ability of the fuel tank not to catch fire on the Bf 109 is however clearly out of place and it should be more consistent with the others. That should be addressed with the upcoming changes in fuel systems as was announced.

 

Cheers,

Edited June 23, 2020 by Aurora_Stealth

[sevenless]

33 minutes ago, unreasonable said:

 

It is not just the fact of fires or leaks that is important but their severity. The report notes that the more likely a round was to cause fires the more severe the fire when they occurred.

 

This sequence of a P-51 gun camera tells me, that it should not be that hard to cause a fire if firing on a 109 from dead six behind. Either the fuel tank or the MW50 tank go boom here. Which again brings me to the question which kind of ammo load do we have in game for the 0,50cal? M2, M8, M20 and what was the ratio for ball to incendiary and what is the ratio in game? :

 

 

http://www.liberatorcrew.com/15_Gunnery/09_ammo.htm

 

Edited June 23, 2020 by sevenless

[unreasonable]

@Aurora_StealthIn this case the problem is not so much detachment or otherwise, but whether hits in the tail/rear fuselage area are allowed to pass through to the tank at all.  A similar test firing side on at the exact location of the fuel tank in each case would give a clearer indication of the fuel tank vulnerability specifically,  but I agree we had better just wait for the current set of changes to be completed.   

Edited June 23, 2020 by unreasonable

[Aurora_Stealth]

@unreasonable

 

Oh I see what you're saying, sorry I didn't realise that it was blocking bullets completely from passing through but within that context it makes perfect sense.

 

I was assuming that it was all getting absorbed within the inside of the fuselage and catching on the radio and other equipment including armour behind the tank or something like that.

 

Fair comment.

Edited June 23, 2020 by Aurora_Stealth

[BCI-Nazgul]

I've often wondered if the pass through mechanics are even implemented in IL2.   Any AP round from most weapons would probably pass completely through a plane from stem to stern unless it hit an engine or other large piece of metal.   The skin certainly isn't going to stop anything coming or going.  That gives it lots of chances to hit something important.

Edited June 23, 2020 by BCI-Nazgul

[unreasonable]

On 6/21/2020 at 4:30 AM, BCI-Nazgul said:

TRACKS

 

OK, here is the M2 vs. a P51 wing.  From a P-39 (x2 M2 .50 cal) my friend fires a short burst, then a few more until he's finally out of M2 rounds.  He then finishes me with the 37mm cannon (you'll see the first wing tip hit with the 37mm.)    Note there is no speed loss with the M2 even after he shoots off the flap and aileron. 

M2vsP51Wing.zip 4.46 MB · 15 downloads

Next we fire the two MG 131s from an ME109 G14.   One short burst and the P51 immediately loses 35 mph.    He then follows up with enough bursts to down the P-51.  Note these are all wing hits only just like the M2 tests.

MG131vsP51Wing.zip 3.43 MB · 2 downloads

And finally the Soviet SVAK (x2 YAK 7B) is used with the same test.   It appears to be about the same as the MG131.

SVAKvsP51Wing.zip 3.24 MB · 2 downloads

 

So finally had time to look at one of these  -the first one. (Which is actually P-51 vs P-51).   I am very puzzled by how anyone could claim that 50 cal wing damage has no speed penalty after seeing that, however "disturbed" they are.

 

I looked at the IAS at various times:

 

0.03 at start - 255 mph

0.26 after first burst - 240 mph

1.12  - 220mph

2.08 before second bust - 210 mph

 

The pilot does a good job of keeping approximately steady altitude and of course rpm and boost are constant throughout. A good test, that plausibly overcomes the usual objections to MP tests.  Too much or too little vs MG131- I have no idea, but if I wanted to prove that 50 cal hits (and not very many at that) inflict an aerodynamic speed penalty I would use this track.

 

 

Edited June 26, 2020 by unreasonable

[BCI-Nazgul]

13 hours ago, unreasonable said:

 

So finally had time to look at one of these  -the first one. (Which is actually P-51 vs P-51).   I am very puzzled by how anyone could claim that 50 cal wing damage has no speed penalty after seeing that, however "disturbed" they are.

 

I looked at the IAS at various times:

 

0.03 at start - 255 mph

0.26 after first burst - 240 mph

1.12  - 220mph

2.08 before second bust - 210 mph

 

The pilot does a good job of keeping approximately steady altitude and of course rpm and boost are constant throughout. A good test, that plausibly overcomes the usual objections to MP tests.  Too much or too little vs MG131- I have no idea, but if I wanted to prove that 50 cal hits (and not very many at that) inflict an aerodynamic speed penalty I would use this track.

 

 

 

I messed up on initial labeling on my original post.  I have deleted the post.   The one that said ShVAK in the original post was the P-39 firing at the P-51.   They were swapped.   I reposted the correct one below.   The correct number should be dogfight.2020-06-20_13-19-11_00.trk   I'm sorry if anyone else was confused.

 

TRACKS

 

OK, here is the M2 vs. a P51 wing.  From a P-39 (x2 M2 .50 cal) my friend fires a short burst, then a few more until he's finally out of M2 rounds.  He then finishes me with the 37mm cannon (you'll see the first wing tip hit with the 37mm.)    Note there is no speed loss with the M2 even after he shoots off the flap and aileron. 

 

M2vsP51Wing.zip

 

Next we fire the two MG 131s from an ME109 G14.   One short burst and the P51 immediately loses 35 mph.    He then follows up with enough bursts to down the P-51.  Note these are all wing hits only just like the M2 tests.

MG131vsP51Wing.zip

 

And finally the Soviet SVAK (x2 YAK 7B) was used with the same test.   It appears to be about the same as the MG131.  Apparently it won't let me upload this one, but it's pretty much the same as the MG 131 test.

Edited June 26, 2020 by BCI-Nazgul

[RedKestrel]

On 6/23/2020 at 5:06 PM, BCI-Nazgul said:

I've often wondered if the pass through mechanics are even implemented in IL2.   Any AP round from most weapons would probably pass completely through a plane from stem to stern unless it hit an engine or other large piece of metal.   The skin certainly isn't going to stop anything coming or going.  That gives it lots of chances to hit something important.

They are. I have caused engine fires and pilot kills by hits from dead six o clock before where the bullets would have to travel almost the entire fuselage.

That said it is probably difficult to not hit anything hard, between armor plates, steel spars, landing gear, etc.

[unreasonable]

8 hours ago, BCI-Nazgul said:

 

I messed up on initial labeling on my original post.  I have deleted the post.   The one that said ShVAK in the original post was the P-39 firing at the P-51.   They were swapped.   I reposted the correct one below.   The correct number should be dogfight.2020-06-20_13-19-11_00.trk   I'm sorry if anyone else was confused.

 

 

 

OK - but on the track of P-51 vs P-51 that you originally posted and which I downloaded, the P-51 is hit by 50 cal and shows a clear, gradual speed loss of about 45mph between being hit the first and second times. 

 

Leaving aside the MG131 comparison, how can this be consistent with your thread title?  Why delete that track instead of leaving it up with the correct label?

 

Since you had deleted it I thought I had better repost it for anyone who wants proof that 50 cal hits do in fact cause speed loss. Naturally I claim no credit as the originator. It is a very good test as MP tests go and you should not be so shy about it.  

 

M2vsP51Wing.zip

[-SF-Disarray]

Are you referring to the track you've posed there? Because there is no P-51 shooting anything in that track. It is a Yak-7 doing the shooting. Fun fact,  at no point in these tests did we shoot anything with a P-51. We wanted to keep the number of guns consistent. So I'm afraid that I have to ask, what are you even talking about? I'm glad you think the methodology is good in the tests, we thought it was a good method too when we did it. So how do you square this 45 mph loss from impact of a short burst from UBS guns but no appreciable loss of speed from a similar burst from the same number of M2's? Before you answer I'd encourage you to go and look at all of the tracks, and do pay particular attention to which guns are doing the shooting.

Edited June 27, 2020 by -SF-Disarray

[unreasonable]

1 hour ago, -SF-Disarray said:

Are you referring to the track you've posed there? Because there is no P-51 shooting anything in that track. It is a Yak-7 doing the shooting. Fun fact,  at no point in these tests did we shoot anything with a P-51. We wanted to keep the number of guns consistent. So I'm afraid that I have to ask, what are you even talking about? I'm glad you think the methodology is good in the tests, we thought it was a good method too when we did it. So how do you square this 45 mph loss from impact of a short burst from UBS guns but no appreciable loss of speed from a similar burst from the same number of M2's? Before you answer I'd encourage you to go and look at all of the tracks, and do pay particular attention to which guns are doing the shooting.

 

Yes you are right - originally watched from the pilots POV in which the only plane visible was the second P-51 as it zooms past the target. Whoops!

 

I have also watched the P-39 vs P-51 track looking at the damage in slow time. This also slows down, but only from 3:01 when there is second level damage graphic.(In the Yak case the second level damage graphic is visible right from the first burst.)  Most of the hits early on are on the flap or aileron, with only first level damage showing on the underside of the wing. There is no damage on the upperside of the wing showing at all until 2:34  From 3:01 there is 2nd level damage on the upper surface and the speed starts to drop after the cannon hit.

 

It seems probable that the speed penalty relates to the level of the visible damage graphic to the wing surfaces alone. Nearly all the 50 cal hits from the P-39 were on the flap or aileron and had no apparent effect on the wing beyond. Even after the flap and aileron were lost there was no apparent speed penalty. How satisfactory any of that is, is an open question, but I am not sure that this is a 50 cal issue specifically. 

 

It is possible to get to the higher levels of wing damage graphic by firing a side MG on an He111 at your own wing.  Set up He111-6 in QMB on autolevel at 3000m and let it find a steady rpm and ATI. Note speed - 290kph in my last check.  Go to side gunner station and fire one box of ammo into the centre of the wing. You should see what looks like three levels of visible damage graphic appearing.  Go back to pilot station and check - the speed will drop by about 50 kph as the AI attempts to stay at 3000m by increasing AoA. So there is a drag (edit: and/or lift) penalty.

 

So that seems pretty good evidence that MG bullets affect speed - I suspect via the visible damage mechanism. If we had a side mounted 50 cal we could check that way too.  Alternately, if you can get enough 50 cal hits into a wing some other way to trigger the higher visible damage, I expect you would also see a speed loss.

 

 

 

        

Edited June 27, 2020 by unreasonable

[BCI-Nazgul]

1 hour ago, unreasonable said:

 

1 hour ago, unreasonable said:

I have also watched the P-39 vs P-51 track looking at the damage in slow time. This also slows down, but only from 3:01 when there is second level damage graphic.(In the Yak case the second level damage graphic is visible right from the first burst.)  Most of the hits early on are on the flap or aileron, with only first level damage showing on the underside of the wing. There is no damage on the upperside of the wing showing at all until 2:34  From 3:01 there is 2nd level damage on the upper surface and the speed starts to drop after the cannon hit.

 

It seems probable that the speed penalty relates to the level of the visible damage graphic to the wing surfaces alone. Nearly all the 50 cal hits from the P-39 were on the flap or aileron and had no apparent effect on the wing beyond. Even after the flap and aileron were lost there was no apparent speed penalty. How satisfactory any of that is, is an open question, but I am not sure that this is a 50 cal issue specifically.       

 

After the final .50 burst is fired both the flap and aileron on that wing had been shot off and I counted nine .50 holes in the end of the wing, yet the plane STILL isn't losing any speed.   The only thing that slows it down is the final shot with a 37mm explosive round in the wing tip.   That's all he had left since his .50s had been completely emptied on my poor P-51.  It's possible some bug in the coding could explain this as you said.   You'll note that neither the MG131 or the ShVAK had any problems putting holes on the wing forward of the flaps and ailerons.   You would think with all the bursts of .50 something would have hit past the trailing edge of the wing.   My friend is a pretty good shot, but not that good.  Also, as far as the visual model goes, from what I've seen ANY (single or multiple) hole by a 131 or ShVAK will lead to a 35 MPH speed loss, BUT further hits do not seem to cause any more speed loss which is a bit odd.   It seems like code says, "If explosive MG hit in wing then Max Speed = Max Speed - 35 MPH" NOT something like, "if explosive MG hit wing: Current Max Speed = Current Max Speed - 35 mph".   A bit simplistic on my part since I didn't take many factors into account,  but there's a big difference there.   Also, we did do a P-51 vs. P-51 test that we did not post and it had the same results.  The amount of M2 guns seems to matter not was far as wing hits go, however, in that test we didn't empty the guns into the wing like we did on the test you watched.   I encourage you to conduct the same tests if you're curious or not convinced.  They're not hard to do as you can see.

1 hour ago, unreasonable said:

So that seems pretty good evidence that MG bullets affect speed - I suspect via the visible damage mechanism. If we had a side mounted 50 cal we could check that way too.  Alternately, if you can get enough 50 cal hits into a wing some other way to trigger the higher visible damage, I expect you would also see a speed loss.    

I can buy the visible damage mechanism as you said, but is it reasonable that four bursts of M2 fire that do enough damage to shoot off the flap and aileron are not sufficient to trigger said visible damage.   Surely more than the 13 total holes I could actually see had occurred.

1 hour ago, unreasonable said:

It is possible to get to the higher levels of wing damage graphic by firing a side MG on an He111 at your own wing.  Set up He111-6 in QMB on autolevel at 3000m and let it find a steady rpm and ATI. Note speed - 290kph in my last check.  Go to side gunner station and fire one box of ammo into the centre of the wing. You should see what looks like three levels of visible damage graphic appearing.  Go back to pilot station and check - the speed will drop by about 50 kph as the AI attempts to stay at 3000m by increasing AoA. So there is a drag (edit: and/or lift) penalty.       

Wouldn't we need to use US M2s to make this a valid test?   The German MGs seem to work fine (sort of) in our tests.

 

One other interesting thing in all the tests.  You'll note that no matter what weapon was firing there were no critical damage messages.   No "landing gear damaged", "aileron rods broken", "guns disabled",  etc...   That seems suspect to me in general.  There's plenty of important stuff in the wing of a plane.

 

Edited June 27, 2020 by BCI-Nazgul

[357th_KW]

59 minutes ago, BCI-Nazgul said:

Wouldn't we need to use US M2s to make this a valid test?   The German MGs seem to work fine (sort of) in our tests.

 

One other interesting thing in all the tests.  You'll note that no matter what weapon was firing there were no critical damage messages.   No "landing gear damaged", "aileron rods broken", "guns disabled",  etc...   That seems suspect to me in general.  There's plenty of important stuff in the wing of a plane.

 

 

The A20 has an AN/M2 .50 in its top turret, but I don't think it has enough traverse to hit itself anywhere but the tail.

[unreasonable]

38 minutes ago, KW_1979 said:

 

The A20 has an AN/M2 .50 in its top turret, but I don't think it has enough traverse to hit itself anywhere but the tail.

 

That is what I found, so it makes it very difficult to do a comparative SP test.  

 

1 hour ago, BCI-Nazgul said:

After the final .50 burst is fired both the flap and aileron on that wing had been shot off and I counted nine .50 holes in the end of the wing,

 

 The "holes" that you are counting are not "bullet holes" created by specific bullets - they are a graphic applied after some level of aggregate assessed damage.  I saw exactly the same "bullet holes"  while running my airfield attack DM tests where the only thing firing was 20mm LAA. (The P-51 then, BTW, was unusually damage resistant. Not sure why you would use it as a target since neither 50 cals nor Soviets would ever have been used against them, the odd blue-on-blue excepted, but never mind that). 

 

If you fire the He111s MG at it's own wing, you will first see "bullet holes", then a great tear in the wing, then another tear nowhere near the impact point of the bullets.  The visual graphic for damage is entirely generic - it just records a cumulative level of damage for each hit box, irrespective of what caused it 

 

What I think the code is saying is that: If level x generic damage reached on wing (not aileron or flap) hit box is reached, then apply damage graphic y and penalty z to lift/drag. On the first level the penalty of lift/drag may well be very small or zero. I have no problem with that. This method is fairly simple and economical, it does not have to count individual hits for MG bullets more than once, and is consistent with the observations of the He111 wing test.

 

1 hour ago, BCI-Nazgul said:

 I encourage you to conduct the same tests if you're curious or not convinced.  They're not hard to do as you can see.

 

 

Actually MP tests are hard to do - you need a friend, and after many years on this forum I do not have any.   

 

I have no problem with your tests - they are the best MP tests I have seen, so much better than the usual crap. What I am challenging is your interpretation.

 

If you think that the 50 call ball is under-powered vs explosive/incendiary shells: well I might even agree with you. I am on record as maintaining that the GAF lobby has an absurdly inflated idea of the typical effectiveness of their mineshells.  But your tests (even after I have watched the right one  ) do not show that 50 cal do not cause any damage to aerodynamics on wing hits. (Your thread title)  Mainly because  it looks as though, as far as the game is concerned, flap and aileron =/= wing.  You hardly hit the wing at all until the cannon was fired.

 

Hence if you could do your excellent MP tests firing from a higher angle so that a significant number of hits were on the wing hit boxes and not on the flap and aileron, you might have  a better case. Or as I suspect, if you can create level 2-3 damage graphics to the wing hit boxes with 50 cal you will observe a speed penalty, just as in the He111 case. 

 

A simple, testable hypothesis. 

 

[HR_Tumu]

Its true, MP tests , or tests on general, are hard to do.

 

I dont know if some tool like tacview can help nothing.

 

The theme of this post es the aparently absence of aerodinamical penality for 0.5 caliber, i understand. ( hitting Bfs or fokes ).

 

Flying bfs i noticed some nice efects... if some of my wings was several damage , plane have a tendence to roll in to this wing... and becomes more hard to handle. But only noticed if i be hitted by 20mm,  several times.  Thats a nice effect, and this is what usually happens to allied planes after one ore to simply, hits of minnesglosh.  For me is a bit overmodeled. But on general , all this effects are nice. 

 

What i think we are claim here,  i think is a more noticiable effect , especially on wing superficies, after be hitted by 0.5,  some decreassing on speed, some  lose of substentation or turn rate... something.  The impresion u have many times, after archive amount of hits on target, is the target fly very well and he no have problems to dogfight u.   I dont expect desintegrated nothing... but i expected win a bit of advantage on combat after hit enemy. 

 

This posible consecuencies after be damaged by 0.50 , on SP seems imposible to test, and on MP cant be validated. I like a no way street.

[unreasonable]

2 hours ago, HRc_Tumu said:

 

 

This posible consecuencies after be damaged by 0.50 , on SP seems imposible to test, and on MP cant be validated. I like a no way street.

 

It could be validated using the OP's MP method, if you can get enough hits onto one area of the wing surface.   One way to do this would be to test a target plane's speed at a set boost/rpm, altitude, etc configuration. Then have you MP buddy fire at your wing on the ground with the A-20 top gun until you get a level of graphics on one wing hit box. Then take off and check the speed at the test configuration. 

 

If I am right about the drag/lift penalty applying at the hit box level, generated according to the level of the graphic, then it makes a difference whether your hits are spread over a number of hit boxes or concentrated on one.  So 20 hits on one hit box might generate a high level graphic and some drag/lift effects, but 4 hits on 5 different hit boxes would not, or to a lesser degree.  (We get something similar in FC with wing breaks, where the probability that a hit on a box breaks the "spar" increases with successive hits).

 

Edited June 27, 2020 by unreasonable

[HR_Tumu]

i understand unreasonable... but this will be a MP test.... u know for MP allways can have Netcode "distorsion"....

 

And i think i cant made a sp mission where first i take a gunner place on A20, damage wing of "test" target and without restart mission, take seat on damaged targed and test it... this is the only way on SP for test it... and i think isnt posible.

 

who knows, maybe for Dev Team or testers ,have avaliable tools for made this kind of tests.

 

pd: anyway for the test u proposse on MP .......   at least netcode only can affect on number of hits needed for reach , graphical damage level we want archive, but no have to affect to posible effects on aerodinamics... then is a good idea. Thx.

Edited June 27, 2020 by HRc_Tumu

[Caudron431]

6 hours ago, unreasonable said:

Mainly because  it looks as though, as far as the game is concerned, flap and aileron =/= wing.  You hardly hit the wing at all until the cannon was fired.

As i remember in the tracks all aircraft wings are shot at the same angle (shots from right behind), in the  exact same manner. If so,  the different aircraft should react exactly the same, on all occurences, then all the wings would be "hardly" hit and the drag effect should be non existent in all cases. So what's causing some aircraft to lose speed and other to keep flying as if no damage occured?

Do you mean that flaps and ailerons act as some sort of damage absorbers and protection for the wing, and that AP or ball ammo cannot go through them to cause damage to the wing?

 

51 minutes ago, unreasonable said:

If I am right about the drag/lift penalty applying at the hit box level, generated according to the level of the graphic, then it makes a difference whether your hits are spread over a number of hit boxes or concentrated on one.  So 20 hits on one hit box might generate a high level graphic and some drag/lift effects, but 4 hits on 5 different hit boxes would not, or to a lesser degree. 

Since the guns in the Airacobra are similarly center mounted perhaps closer to one another than the bf 109 131s and the Yak UBSs, then what could cause the bullets to spread on the surface of the wing causing them to hit different boxes as in your theory? (tests were not made by wing mounted .50cal.)

 

 

Edited June 27, 2020 by Caudron431Rafale

[unreasonable]

4 minutes ago, Caudron431Rafale said:

As i remember in the tracks all aircraft wings are shot at the same angle (shots from right behind), in the  exact same manner. If so,  the different aircraft should react exactly the same, on all occurences, then all the wings would be "hardly" hit and the drag effect should be non existent in all cases. So what's causing some aircraft to lose speed and other to keep flying as if no damage occured?

Do you mean that flaps and ailerons act as some sort of damage absorbers and protection for the wing, and that AP ammo cannot go through them and cause damage to the wing?

 

Since the guns in the Airacobra are similarly center mounted perhaps closer to one another than the bf 109 131s and the Yak UBSs, then what could cause the bullets to spread on the surface of the wing causing them to hit different boxes as in your theory? (tests were not made by wing mounted .50cal.)

 

You can clearly see that with the other guns, the wing hit boxes show damage graphics at higher levels than from the 50 cal.  That, I think, is what causes the speed loss. Explosive rounds in BoX have always had an area effect: even if they were mostly hitting flap and aileron they would still create damage on other hit boxes. In the case of the P-51 that does not look as though it is happening with the 50 cals.  Those are just the facts of what happens in the tests. 

 

I am not arguing that the relationship between explosive HMG rounds and ball HMG rounds is correct, or that the absolute damage from either is correct.  I would have thought ball rounds would tend to penetrate more than they appear to in the P-51, and I would not be surprised if they penetrate more on other planes, since the P-51 was very damage resistant in my own tests in previous DM versions.

 

 I am simply arguing that we have not yet seen a case that 50 cal hits to the wing never cause speed loss, because so few of the hits in the test actually damaged the wing. What we see is that the first level graphic damage on the wing is insufficient to cause speed loss, and that flap and aileron loss also appear not to influence speed.   That may be true for all munitions and all aircraft - nothing to do with the 50 cal.  

 

If you do my suggested He111 test you can see that rifle caliber rounds create a  speed loss when they trigger the higher level damage graphics.  Get enough 50 cal hits and I expect to see a similar result - if not, there is a bug.  

 

My observation about concentrated vs spread hits is nothing specific to do with the OP's test. It is just how I think the DM works. I know it works that way for damage to the spars, because AnP told us so.  It does have implications for fighting or testing - a concentrated burst will be far more effective in reaching the graphic threshold than a random spray of the same number of hits, which seems reasonable to me.

[-SF-Disarray]

I've brought this up in other threads talking on this same issue, and I know we didn't include this in the test data we've shown here but, we did a similar test including cannons shooting at a P-40, this test was done without shooting the MGs to isolate the cannon's effect. The effect of a single HE cannon shell and at most 1 AP shell from an MG-151/20 is remarkably similar to the effect from the kinds of MG bursts we used in these tests. I understand how outlandish this sounds. If the visual model is influenced by the physical modeling as Unreasonable is positing, i.e. when X damage is simulated Y visuals are applied, it would follow that the HE effect of the MG rounds in both the MG-131's and the UBS guns are not distinguishable from the HE effect from the cannon rounds. For reference the filler used in the 131 and the 151/20 rounds are .9 g and 18.6 g respectively, so should obviously be very different in effect. Specifically, the smaller charge should cause more localized damage but as can be seen the damage is applied over most of the wing area when 131 rounds hit.

 

As for hits to the wing never causing speed loss being shown, I'm not convinced. A round, much less a high velocity .50 round, fired from 250 m, our shooting distance, should have little trouble passing through the wing, even if it hit at the back end. Given our firing position that would put the exit wound at or near the leading edge. I'm given to understand that this should be the best case scenario for causing aero damage. So either the damage effects of AP rounds are not being carried forward through the flap/aileron and into the wing, a problem, or the damage effects are being carried forward but just not doing anything, still a problem.

 

While I know it won't qualify as scientific evidence I have gathered lots of field data that pertains to this subject. You see, I'm what some people describe as 'overly aggressive' when I fly 109's, it is fun don't 'at me', and so I naturally get shot at a lot by M2 armed opponents. Some of them are very good shots and hit me all over the plane from angles that would necessitate hitting the wing from the top or bottom. Often times, after these fights I bring the plane back full of holes but with no difficulty in terms of speed or handling. The only thing's that get me into trouble are when the engine takes a hit and is either destroyed outright or set on fire, or when the pilot wins the bullet lottery. If none of these things happen I can carry the fight and often times win in planes that should be floundering as it is more holes than plane. But when a 20 mm cannon is thrown into the mix I find myself needing to fly like I do against German planes. I can't afford to get shot once if I want to win that fight because the cannon rounds will kneecap the plane's performance. And yes, I know, anecdotal data and all that, but when anecdotal data consistently point to the same conclusion there is something to it.

[unreasonable]

"...when anecdotal data consistently point to the same conclusion there is something to it." I agree with that, but the "something" is not necessarily what you first think of. Hence the value of tests that isolate variables, at least as well as we can in the game. 

 

Do your MP test but use an A-20 top gun to put enough rounds into a single wing hit box of the target plane to trigger levels 2 and 3 of the damage graphic. See if there is no speed penalty.

 

On the area effect of MG131 vs 20 mm - that can be tested off line since all you need to see is the hits needed to trigger the visible graphic, (edit if you do it online you can count hits reasonably accurately on the target plane using the mission log =1 in startup.cfg). 

 

I agree the MG131 should have a much more local effect, but it can only be as local as the size of one hit box. You will get selected damage graphics at random over the whole hit box: the game does not distinguish to a lower level. If the hit box is large - as for instance in the case of the He111 wing - then you will get damage graphics in areas that look well away from the actual hit location. Something that is very clear in the case of firing at your own wing in the He111. So I do not think that the area of the visible damage is a reliable guide, unless it is extending to hit boxes that clearly were not hit by the impact.

 

What I would expect in that case is that MG131 is much less likely to do splash damage to other areas - eg hits on the wing will do damage to fuel tanks, pilot, engine etc far less often than would 20mm.  Again, testable, but requiring a number of trials to get a clear result.

Edited June 28, 2020 by unreasonable

[unreasonable]

The best I can get with SP is the attached mission, which seems pretty clear to me that 50 cal hits cause speed loss - if you get enough of them. I used the tech spec page maximum TAS for the He111-6 at 2000m and created a high priority waypoint with that speed converted to IAS (362kph).  Player is in P-51 (adjust fuel load manually as desired, ammo set to unlimited).  He111 is at 10 o'clock.

 

The idea is that the He111 will try to fly level at that speed. If it is suffering lift/drag penalties it will not be able to. It will neither evade nor shoot back. Take care not to hit the engines. 

 

Matching speeds initially I was recording about  220mph IAS - 354 kph.  I then shot at the outer wing until I got clear level 2 damage graphics. (One good on target burst is all it takes). Then matched speed again. Fired again until the damage looked like level 3, matched speed again. By the time I had clear level 3 damage over much of the wing I was matching speed at below 180 mph (300 kph)

 

I was making a track of this and then, just about to finish: power cut! (Happens in the rainy season quite often, unfortunately). So track was corrupted. But seeing for yourself is always better so try the mission. Also that was the first time I had tried the game's P-51 so I am sure many of you can do this much more elegantly.  

 

50 cal vs He111 mission.zip

Edited June 28, 2020 by unreasonable

[gimpy117]

On 5/15/2020 at 6:15 PM, CountZero said:

Its comon knowlade that when Germans saw Mustangs over Berlin, they just relised the flys and drop bugs in air and won the war. P-51 was rather poor peace of machine and pilots trown in it didnt even know that single bug could be death to them.

We're just luckily that the Germans didn't use a mine shell on New York. They would have won the war. We've all seen the simulations, a single MG/FF mine shell can destroy anything

[LColony_Kong]

I agree with the OP, but I'd like to add a few other things that affecting .50 cal performance at the moment.

 

Lack of Harmonization: The guns in game right now all fire to a fixed point. In reality the standard was to have each of the gun pairs converge at different ranges. Watch gun camera footage, analyze convergence pattern charges, or simply look at video games where this is modeled (DCS etc.) What harmonization does is create a dense field of fire so that when the enemy aircraft passes through that general area you get a shot gun effect. So instead of all your rounds hitting at one point, the entire aircraft gets saturated, making it more likely to hit vital components and do combination effects. It also makes it more likely that you get any hits at all when you are not at the best range for a harmonization cone, because you have some guns converging at closer and further ranges. Ideally the game would allow (as it was done IRL) for the pilot to customize both the convergence range and the harmonization pattern. This could be done easily by simply allowing the player to adjust convergence for each pair of guns. So for example in inboard guns could be at 275m, center guns at 300m, and outboards at 325. Etc.

 

Lack of API: My understanding is that we do not have API modeled in game right now. Obviously API is not some kind of explosive round, but it would certainly increase the chance of causing fires. However another problem regarding this is that we do not have the hit flashes modeled very well in the game right now. This isnt just a problem with the American .50s, but most other rounds like 20mm HEI give off other effects that let you know you hit. The hit flashes from .50cal impacts should be large and obvious, and this matters because it would let the player know how well they are hitting the target. With the current .50 cal impact effects if can be hard to know where you point of impact is, and sometimes you cant tell if you hit at all.

 

[Bremspropeller]

On 6/22/2020 at 6:08 AM, alpino said:

I've posted this on another topic, I think it might be interesting to show here as well.
this plane got shot by a A-29 armed with browning M3s
 

 

Shots went through the spar, hit the tank and did some heat- or fire-damage, exiting the tank.

Very interesting find, thanks!

 

Another pic:

 

Edited July 6, 2020 by Bremspropeller

[LColony_Kong]

1 hour ago, Bremspropeller said:

 

Shots went through the spar, hit the tank and did some heat- or fire-damage, exiting the tank.

Very interesting find, thanks!

 

Another pic:

 

It is clear form these images that .50 cal causes more structural damage than some would like to think

[Bremspropeller]

11 minutes ago, [TLC]MasterPooner said:

It is clear form these images that .50 cal causes more structural damage than some would like to think

 

Only if there's a significant secondary event triggered off - like a fuel-fed fire in this case.

[LColony_Kong]

7 minutes ago, Bremspropeller said:

 

Only if there's a significant secondary event triggered off - like a fuel-fed fire in this case.

Nah you can see from these images that the large holes in front are caused by the exit of the bullets. The entry holes line up with the huge gashes left by the exit wounds. The fire is not what caused those huge holes. But whatever damage the fire did is certainly where are missing API would come in. The one I did not mark exited the front.

 

Edited July 6, 2020 by [TLC]MasterPooner

[Barnacles]

Just now, Bremspropeller said:

 

Only if there's a significant secondary event triggered off - like a fuel-fed fire in this case.

No, I only partially agree on this. It is possible to get significant exit wounds because of 'rip and tumble' effects, without secondaries. I have no evidence at what frequency it would happen, but I have seen 50 cal hits for real on engine casings on boats, and it does occur with significant frequency 

[Bremspropeller]

18 minutes ago, [TLC]MasterPooner said:

Nah you can see from these images that the large holes in front are caused by the exit of the bullets. The entry holes line up with the huge gashes left by the exit wounds. The fire is not what caused those huge holes. But whatever damage the fire did is certainly where are missing API would come in. The one I did not mark exited the front.

 

No, the exit-damage can't be much larger than the projectile's projected area - even with outward ripping and peeling (keep in mind, at the airspeeds involved, there's little backward peeling due to airstream).

 

There is no way of figuring out which size the exit-holes actually were, due to the fire-damage.

It is safe to say that the fire-damage played an integral part in the damage-picture. All the exit-holes show extensive fire-abrasion and none are originally sized.

On top, the skin shows extensive heat-damage.

 

Curb your enthusiasm.

 

 

 

I think the second trail from the bottom is wrong.

The exit is associated with the entry on the left. The entry you attached with that exit is actually associated with the exit below the large gash.

Like this:

 

Gives you an idea about a normal "punch through" exit without tumbling.

Note the lack of additional fire-damage associated with the normal punch through

Edited July 6, 2020 by Bremspropeller

[Barnacles]

2 minutes ago, Bremspropeller said:

 

No, the exit-damage can't be much larger than the projectile's projected area - even with outward ripping and peeling (keep in mind, at the airspeeds involved, there's little backward peeling due to airstream).

 

There is no way of figuring out which size the exit-holes actually were, due to the fire-damage.

It is safe to say that the fire-damage played an integral part in the damage-picture. All the exit-holes show extensive fire-abrasion and none are originally sized.

On top, the skin shows extensive heat-damage.

 

Curb your enthusiasm.

That's true. In damage assessment diagrams, there's a cone of 'fragments' that radiate from the back of the point of impact. Worst case scenario you get a fairly bigger area of damage in the surface behind the hit, but I think you're right in that these holes may have been enlarged by a violent burning of fuel. 

 

[LColony_Kong]

2 minutes ago, Bremspropeller said:

 

No, the exit-damage can't be much larger than the projectile's projected area - even with outward ripping and peeling (keep in mind, at the airspeeds involved, there's little backward peeling due to airstream).

 

There is no way of figuring out which size the exit-holes actually were, due to the fire-damage.

It is safe to say that the fire-damage played an integral part in the damage-picture. All the exit-holes show extensive fire-abrasion and none are originally sized.

On top, the skin shows extensive heat-damage.

 

Curb your enthusiasm.

No that is flat out wrong. Exist holes are generally significantly larger than the entrance diameter, this due to the fact that the metal must be pushed outward. Find tons of images of this online including videos of .50cals specifically going through metal targets like cars.

 

Also the fire damage did cause that color changing entirely, most of that is just paint peeling off from the impacts.

[Barnacles]

Like this one @[TLC]MasterPooner? That's lots more than .50"

 

[Bremspropeller]

2 minutes ago, [TLC]MasterPooner said:

No that is flat out wrong. Exist holes are generally significantly larger than the entrance diameter, this due to the fact that the metal must be pushed outward. Find tons of images of this online including videos of .50cals specifically going through metal targets like cars.

 

Also the fire damage did cause that color changing entirely, most of that is just paint peeling off from the impacts.

 

1) Disagree. See edited post.

 

2) It's actually the metal getting hot enough to have the paint and primer melt off.

 

 

 

 

[LColony_Kong]

3 minutes ago, 71st_AH_Barnacles said:

Like this one @[TLC]MasterPooner? That's lots more than .50"

 

or this one.

 

 

[Barnacles]

Equally there's a lot of evidence that 50 cals can't even penetrate flesh. 

 

[LColony_Kong]

17 minutes ago, Bremspropeller said:

 

No, the exit-damage can't be much larger than the projectile's projected area - even with outward ripping and peeling (keep in mind, at the airspeeds involved, there's little backward peeling due to airstream).

 

There is no way of figuring out which size the exit-holes actually were, due to the fire-damage.

It is safe to say that the fire-damage played an integral part in the damage-picture. All the exit-holes show extensive fire-abrasion and none are originally sized.

On top, the skin shows extensive heat-damage.

 

Curb your enthusiasm.

 

 

 

I think the second trail from the bottom is wrong.

The exit is associated with the entry on the left. The entry you attached with that exit is actually associated with the exit below the large gash.

Like this:

 

Gives you an idea about a normal "punch through" exit without tumbling.

Note the lack of additional fire-damage associated with the normal punch through

Your redraw hardly changes the result. It still shows rather large exits far more often than not. And most of that missing paint is not from the fire, that is from the paint coming off from the exits and entrance points. This happens all the time with bullet impacts and is not a novel phenomenon. Some of the discoloration was from the fire but the holes and the missing paint is not.

[Barnacles]

[Aurora_Stealth]

@[TLC]MasterPooner

 

FYI

 

On 6/22/2020 at 12:20 PM, Aurora_Stealth said:

@alpino

 

Cool photo, nice to see someone having fun using that as target practice!

 

From the exit marks it looks like they are using modern APEI ammunition, not surprising though as the A-29 Tucano is a modern turboprop and they will nowadays be supplied with the latest ammunition technology.

 

I believe FN Herstal produce the M3's for the A-29 Tucano and from the size of the blast and burn marks on exit I'd suggest they're using APEI (Armour Piercing Explosive Incendiary) rounds. This wouldn't have been available in WW2 for the .50 calibre unfortunately. The more typical API (Incendiary) would have been though, but those would just pierce and light-up but not create such large exit holes.

 

The photo from Alpino is not using typical .50 calibre ball or even straight API rounds. Its also an M3 machine gun not an M2 and this was fitted to a modern aircraft and fired at a range we don't know.

 

This is really muddying the water here and people are now trying to use this photo and assimilate it to something else. In either case this wasn't what was seen in WW2 Allied fighters using M2's -  the photo shows damage from an APEI shell i.e. using a form of high explosive not invented for the M2 until after the war hence the holes being much much larger than any entrance or exit holes that just the bullet typically produce on its own as ball / AP.

 

It is commonly accepted that most bullets leave a larger exit hole (provided they can continue to penetrate and exit) because they are less stable after hitting which is basically tumbling - but it also depends on what they're actually penetrating - an engine block or another dense material can cause unusual exit holes but going through two thin metal skins may alternately leave just a similar very small exit hole as well.

 

Best to stick to WW2 photos of .50 calibre damage caused by WW2 aircraft - it'll save for a lot of speculation.

Edited July 6, 2020 by Aurora_Stealth