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

[JG13_opcode]

1 hour ago, CUJO_1970 said:

Oh look another .50 cal complaint thread, after all it’s only been like ten minutes since the last one.

 

What made you think this was a useful reply?

 

The OP seems well founded.  I'd like to see a track but the methodology seems reasonable to me.

[CUJO_1970]

7 minutes ago, JG13_opcode said:

 

What made you think this was a useful reply?

 

The OP seems well founded.  I'd like to see a track but the methodology seems reasonable to me.

Because there are already so many threads about the exact same topic, it is not necessary to keep starting new ones about it over and over again ad nauseam.
 

Maybe we could start 17 different threads about how the MG17 is completely useless and when I start the 18th we could all discuss how well founded my new thread about the exact same thing is?

 

 

[-SF-Disarray]

Maybe that there are so many threads all talking about the exact same thing should tell you something?

[CUJO_1970]

Just now, -SF-Disarray said:

Maybe that there are so many threads all talking about the exact same thing should tell you something?

 

Yes it tells me there are a lot of entitled dead horse beaters that frequent the forums.

[JG13_opcode]

I dunno man, when I get real wound up like you are here I find it's useful to take a step back a realize that it's not important to keep making "clever" comments in threads.

 

I mean it seems like you really care about this issue, maybe you could post something substantive.  Otherwise, if you don't care, why keep going so hard?

[sevenless]

5 hours ago, -SF-Disarray said:

 

You do realize that posting a bunch of technical documents that are all in German into a conversation that is taking part entirely in English with no context and no explanation of their contents is decidedly unhelpful, right? Did it never occur to you that the people having this conversation might not understand a single word of any of this? Somehow I think it might not have. You may be shocked to learn that all of this means nothing to me. It would be as useful as me posting the entire technical manual for the Yak 1 in it's original format and calling that an argument.

 

Need a tissue?

 

[Bremspropeller]

 

German humour about german bureacracy ?

 

16 hours ago, -SF-Disarray said:

You do realize that posting a bunch of technical documents that are all in German into a conversation that is taking part entirely in English with no context and no explanation of their contents is decidedly unhelpful, right? Did it never occur to you that the people having this conversation might not understand a single word of any of this? Somehow I think it might not have. You may be shocked to learn that all of this means nothing to me. It would be as useful as me posting the entire technical manual for the Yak 1 in it's original format and calling that an argument.

 

Sometimes going the extra-mile and consulting google-translate does help.

Most *knowledgeable* people here haven't been born with that knowledge and took their time, gathering documents or books.

Just acting as if you're entitled to a consumer-ready version of a random document is a bit easy on your side.

[CUJO_1970]

16 hours ago, JG13_opcode said:

I dunno man, when I get real wound up like you are here I find it's useful to take a step back a realize that it's not important to keep making "clever" comments in threads.

 

I mean it seems like you really care about this issue, maybe you could post something substantive.  Otherwise, if you don't care, why keep going so hard?

Yeah I’m not actually wound up at all - even your little straw man that I am doesn’t bother me ?. The smiley face proves it.

Why should I post something “substantive” in this latest .50 cal thread when I’ve already posted test results in another .50 complaint thread, then I’d be just as responsible for the horse beating. 
 

You must have missed it though, being as it’s not easy to wade through all the same threads on exactly the same subject. 

 

[BCI-Nazgul]

Quote

Cannons were objectively better for air-air combat during WW2, pilots were not the best judge of this. Very few US pilots ever hit a plane using a cannon, or even fired one, how can they make valid comparisons?  Read a800394 on Airplane Vulnerability, US ballistics tests done by people who know what they are talking about. 

 

The USAF stuck with 50 cals throughout because they were adequate when used in numbers, in mass production so plentiful and cheap.  Additionally the US procurement system made a hash of setting the right tolerances to make US mass-manufactured 20mm effective.    

 

BTW I have no idea if the MG 131 is doing too much structural damage.  The wider .50 cal topic has been discussed at length in the forum, but I accept that a forum structure does not lend itself to easy searching.  

 

I can accept that 20mm might be better for air to air combat especially in the planes that are armed with four of them (FW 190, Tempest, etc...)   My problem is that US .50s are objectively bad to horrible for air to air combat in this game compared to a far lesser number of MG 131s.  My opinion is that some factor(s) has not been modeled properly, however, without knowing technical details of the system they are using it is impossible to say what that is.  I seriously doubt that the Army Air Corps and US Navy would have stuck with a weapon that is as poor as the one the depicted in IL2.   I'm not expecting them to be as good as the 20mm, however, I do expect them to easily down other planes.  With the current modeling,  I would be happy as a clam to have four MG 131s mounted on a P-51 instead of six of the US M2s.   Next we're going to do the same test with the Soviet 12.7mm and see how they are compared to the M2.

[unreasonable]

4 hours ago, BCI-Nazgul said:

 

I can accept that 20mm might be better for air to air combat especially in the planes that are armed with four of them (FW 190, Tempest, etc...)   My problem is that US .50s are objectively bad to horrible for air to air combat in this game compared to a far lesser number of MG 131s.  My opinion is that some factor(s) has not been modeled properly, however, without knowing technical details of the system they are using it is impossible to say what that is.  I seriously doubt that the Army Air Corps and US Navy would have stuck with a weapon that is as poor as the one the depicted in IL2.   I'm not expecting them to be as good as the 20mm, however, I do expect them to easily down other planes.  With the current modeling,  I would be happy as a clam to have four MG 131s mounted on a P-51 instead of six of the US M2s.   Next we're going to do the same test with the Soviet 12.7mm and see how they are compared to the M2.

 

You are conflating two issues that need to be kept apart.  

 

1) Performance of game .50 cal vs RL .50 cal

2) Performance of game .50 cal vs game MG131

 

On issue 1)

 

The US Ballistics Lab tested .50 cal (using API-T M20) vs P-47s - details in a800394  They have a single shot hit probability of an A kill (downed in < five minutes) of  0.017  That means that if you shot a large number of P-47s,  half of them would be shot down by 40 hits or less, half needing over 40.  

 

Planes smaller than the P-47 will be easier to down after n hits, since the pilot is the same size, but then smaller planes are harder to hit.  In terms of the number of shots fired required, the number would be similar.

 

That assumes hits are independent, which they are not entirely: hits on fuel tanks increase the probability of a later hit starting a fire. So the report examines this too, concluding with a p of an A kill after 10 hits at about 0.18    Compare this to 10 hits at 0.017 independently, the cumulative probability is 0.158  So the additional effect of these compounded hits is real, but not massive. 

 

These are not high probabilities, especially compared to those of the various HE cannon shells.  This is not just my opinion - it is the result of live firing tests done by people whose job it was to assess weapon effectiveness for the US government.

 

On issue 2)  

 

You would, perhaps, be even more happy if you had six M2s that fired explosive/incendiary rounds.  German technology for specialized shells for air to air combat was well ahead of that of the US. That does not make them wonder weapons, but you would expect there to be some benefits. 

   

 

 

[BCI-Nazgul]

You didn't watch the tracks I posted since there have been zero downloads.  I have given you the time to read your post/opinion.

 

When you can fire the entire magazine of two M2s into one wing of a plane that isn't even trying to evade and it suffers no speed loss something is wrong.   We literally shot the aileron and flap off one wing and it was still running at full speed while a short burst with two 131s resulted in an immediate 35 mph speed loss.  As far as the Germans having better rounds than the Americans I can buy that, but if that's the case why did the Germans stop using their HE rounds and switch to API if they were better?   And, second, why don't US planes get API in the game?  Also, bear in mind our earlier test had the same results with six .50s (not just the 2 gun track I posted) being fired.  As far as your "shooting down" probabilities, OK let's just say that's true,  what about the non-killing rounds doing some damage that results in a retreat by the enemy or loss of capability that renders staying in the fight more likely to get the target shot down?  Currently, wing hits by the M2 .50 don't seem to do anything to make the enemy less capable of fighting.  Even a fuel tank hit doesn't affect they enemies ability to fight until they run out of gas.   Watch the tracks.

Edited June 21, 2020 by BCI-Nazgul

[Caudron431]

I just saw your tracks. First thank you for taking the time to test, it looked difficult to do.

 

In the tracks the german 13mm and the soviet 12,7 mm seem totally different from the 50cal M2. I'm not saying something is wrong but they seem to be weapons from different categories with difference greater than between .30 and .50 for instance. (perhaps they really were, i was unaware of that, always though they were comparable)

Surprising, i didn't expect that much difference. What is troubling is that the aicraft does'nt lose speed even when losing parts when hit by the M2, strange to me indeed. I wonder what could explain this?

Have you tried this with other wings than the 51 ones? Do you still have a track when firing at the same wing with 6 M2?

Anyway, i now see what you mean and can see you testing was made in good faith, sorry for not taking the test seriously at first and thank you for the time it took to you.

 

6 hours ago, unreasonable said:

You would, perhaps, be even more happy if you had six M2s that fired explosive/incendiary rounds.  German technology for specialized shells for air to air combat was well ahead of that of the US. That does not make them wonder weapons, but you would expect there to be some benefits. 

 Looking at the tracks i though the same exactly, but its the magnitude of the benefits that is surprising (not saying they are incorrectly modelled) while in the same time two different designs (German and Russian) seem to produce similar effects in the tracks.  Very interesting.

Edited June 21, 2020 by Caudron431Rafale

[unreasonable]

4 hours ago, BCI-Nazgul said:

You didn't watch the tracks I posted since there have been zero downloads.  I have given you the time to read your post/opinion.

 

When you can fire the entire magazine of two M2s into one wing of a plane that isn't even trying to evade and it suffers no speed loss something is wrong.   We literally shot the aileron and flap off one wing and it was still running at full speed while a short burst with two 131s resulted in an immediate 35 mph speed loss.  As far as the Germans having better rounds than the Americans I can buy that, but if that's the case why did the Germans stop using their HE rounds and switch to API if they were better?   And, second, why don't US planes get API in the game?  Also, bear in mind our earlier test had the same results with six .50s (not just the 2 gun track I posted) being fired.  As far as your "shooting down" probabilities, OK let's just say that's true,  what about the non-killing rounds doing some damage that results in a retreat by the enemy or loss of capability that renders staying in the fight more likely to get the target shot down?  Currently, wing hits by the M2 .50 don't seem to do anything to make the enemy less capable of fighting.  Even a fuel tank hit doesn't affect they enemies ability to fight until they run out of gas.   Watch the tracks.

 

I have not looked at the tracks because I am not disputing your test results. I believe you, all right?  (Even though the developers have repeatedly said they will not look at DM tests done online. It is your time wasted, not mine). I do not even have strong views about how much, if any, aerodynamic effects bullet holes from 50 cal or 303s should have.

 

What I am questioning is your assumptions about the overall effectiveness pf .50 cals.  These are not my probabilities - they are the US Government's probabilities. Read the document.

 

As to whether the API is modeled in the game or not - it could be already.  What is important is the results, not some coloured bullet shapes on a GUI.  API is more effective in setting fire to fuel tanks that are already leaking.  Solid ball rounds can also do this, just not as often. Happens in FC with 303s fairly often.  If we knew the formula the game uses to decide if a fuel tank catches fire we could tell if the results we have now are effectively modeling API or not. I think not but you never know.  

 

If you are firing a mixed battery of cannons and HMGs, having explosive bullets for the HMGs is a bit pointless - 20/30mm cannon shells do a far better job of shredding surfaces, especially with mineshells designed to do just that.  Leaving the HMGs to do AP and incendiary work makes perfect sense. 

 

I would prefer it if the game had a distinct ball and API round - we need incendiary bullets in FC too - but there may be limits in how much ammunition variation the game can handle when you have multiple guns firing at high rof.

 

[BCI-Nazgul]

"Have you tried this with other wings than the 51 ones? Do you still have a track when firing at the same wing with 6 M2?"

 

We tried it on P-40 wings and 109 wings, it seems to apply across the board.  I'm 99% sure it's not the wings, but the guns themselves.  We did not make a track for the x6 M2, but I can assure you that the results of a short burst are the same.   We did not test how much fire from 6 M2's would actually destroy a plane just with wing hits.   Maybe you wouldn't need to fire every round in the magazines, I don't know.   The short burst results were the same results as only 2 M2's.   Also, there were no critical hits with the M2's or most of the other guns for that matter except when the MG 131 finally lit the wing on fire after several long bursts.  One of my friends is opening wondering if somehow the US .50s were mis-assigned damage parameters equal to .30 cal guns because there really isn't much difference in effectiveness.

 

(Even though the developers have repeatedly said they will not look at DM tests done online. It is your time wasted, not mine).

 

So, if they won't look at tracks how are we supposed to get them to at least read this in case it is a bug?   They already moved my thread out of the "bug" section into this section which appears to be an opinion section.

Edited June 21, 2020 by BCI-Nazgul

[unreasonable]

1 hour ago, BCI-Nazgul said:

 

So, if they won't look at tracks how are we supposed to get them to at least read this in case it is a bug?   They already moved my thread out of the "bug" section into this section which appears to be an opinion section.

 

Then perhaps not having an aerodynamic penalty for ball round hits is a pragmatic design decision, which probably applies to all calibers of ball and AP, not just .50 cal.  IE it is not a bug,  but working as intended.

 

If you want to argue that the interpretation in the game is far from reality, you need an external document or similar as a reference and an offline test that demonstrates that game results are different. Same as for FM issues.  Otherwise all you have is an opinion. The developers not agreeing with you on the facts, or how to interpret them into the game, does not constitute bugdom. 

 

If 303s and 50 cals inflicted the same damage I think that would be a bug - hard to imagine that would be intended. Luckily, it would be comparatively easy for you to check whether 303s and 50 cals have been assigned the same damage parameters - there are bombers with these weapons in gunner stations.

 

Use the ME, park an AI target plane in the field of fire of a bomber on the runway, and fire bursts from a gunner station at a defined part until it falls off. Your round count will only be approximate, but good enough to detect if they are essentially the same.  Do that 50+ times for each gun, counting the rounds fired, and you would have a fairly robust distribution. Plot the distributions - it should be fairly clear if there is a meaningful difference.  I would be astonished if there was not - but mistakes do happen.

[SAS_Storebror]

6 minutes ago, unreasonable said:

Then perhaps not having an aerodynamic penalty for ball round hits is a pragmatic design decision, which probably applies to all calibers of ball and AP, not just .50 cal.  IE it is not a bug,  but working as intended.

 

If you want to argue that the interpretation in the game is far from reality, you need an external document or similar as a reference and an offline test that demonstrates that game results are different. Same as for FM issues.  Otherwise all you have is an opinion

 

In that case, please forgive me when I voice my opinion that such a design decision would not be pragmatic, but bold.

Saying "HE rounds slow you down by 30 mph and AP just polished the surface" is like saying "Any bomb with a weight less than 500 pounds will cause damage to unarmoured vehicles only, and if the weight is less than 250 pounds it will only damage it if the driver has blonde hair".

You will hardly find evidence for the opposite, 'cause the fewest attack reports will include the drivers' hair colour, yet human logic dictates that it's @unreasonable.

.

Mike

[BCI-Nazgul]

20 hours ago, unreasonable said:

 

On issue 1)

 

The US Ballistics Lab tested .50 cal (using API-T M20) vs P-47s - details in a800394  They have a single shot hit probability of an A kill (downed in < five minutes) of  0.017  That means that if you shot a large number of P-47s,  half of them would be shot down by 40 hits or less, half needing over 40.  

 

Planes smaller than the P-47 will be easier to down after n hits, since the pilot is the same size, but then smaller planes are harder to hit.  In terms of the number of shots fired required, the number would be similar.

 

That assumes hits are independent, which they are not entirely: hits on fuel tanks increase the probability of a later hit starting a fire. So the report examines this too, concluding with a p of an A kill after 10 hits at about 0.18    Compare this to 10 hits at 0.017 independently, the cumulative probability is 0.158  So the additional effect of these compounded hits is real, but not massive. 

 

These are not high probabilities, especially compared to those of the various HE cannon shells.  This is not just my opinion - it is the result of live firing tests done by people whose job it was to assess weapon effectiveness for the US government.

 

I agree with your/US numbers of hits required to down a plane.  I'd like a source link if possible.  My reading is that the average number of hits required was in the mid to high teens.   Since most enemy fighters were about 1/2 or less the size of the P-47 this tracks pretty well with the test numbers you quoted.    But that really isn't my main concern.    My problem is that non-killing hits don't seem to have any affect on the target when they hit the wings.   We have not tested other areas like the tail and mid-fuselage, but that might be interesting.   It is possible that only cockpit and engine hits are going to have any affect on the target.   It is worth nothing that even using your numbers the six .50 on the average US fighter are putting out 80 rounds per second ((6x800)/60), so one would expect very serious damage to an enemy plane from even a short burst even if less than 25% of the rounds hit anything.   That doesn't seem to track with results we're seeing in multiplayer or with historical accounts.

[unreasonable]

https://apps.dtic.mil/dtic/tr/fulltext/u2/a800394.pdf  

 

Relative "size: depends on the aspect. Here is a graph from some old tests of LAA vs planes (old DM) where I constructed an index of size from a behind, slightly below and to the side angle, since that was when most planes were being hit.  I used the IL-2 viewer to take screenshots of the models and counted pixels in GIMP.  The P-47 is about 50% bigger than the 109s from this angle and was getting hit about 50% more often.  Do not guess - measure.

 

If you wanted to construct a kill probability table for hits similar to those in the report for another fighter, you need to know the % of the total aspect presented by the pilot, engine and fuel tank from the angle used in the report for the P-47.  The pilot is clearly a proportionately bigger target in a smaller plane, but that might not be true of the other systems.  You would have to make a couple of extra assumptions about vulnerability, armour etc as well, in line engines being more fragile, for instance.  

 

 

As to whether bullets affect the wings specifically - easy to test this offline. As I described, make a mission so that you can use bomber gunner stations against a target AI on the ground. That will not tell you about possible speed loss but it will certainly test the hypothesis that 303 and 50 cal bullets do the same damage.  You might also be able to fire your bomber guns in flight at your own wings while in auto level to detect speed loss.  What ever you do you have to do it enough times to make sure you are getting a representative sample. 

 

303 bullets certainly affect wings in FC - both in terms of snapping the "spars" that withstand G and in triggering the levels (3?) of graphics representing surface damage. 

 

5 hours ago, BCI-Nazgul said:

 It is worth nothing that even using your numbers the six .50 on the average US fighter are putting out 80 rounds per second ((6x800)/60), so one would expect very serious damage to an enemy plane from even a short burst even if less than 25% of the rounds hit anything.   That doesn't seem to track with results we're seeing in multiplayer or with historical accounts.

 

Not necessarily. As you observe, the only hits with MG bullets that have a high probability of downing the target are on the critical systems.  If you concentrate fire on the least vulnerable areas of the target you will get far fewer kills.  The "B kill" number from the report is 0.037  (B kill = fails to RTB in 30 minutes, includes A kills)   (1-.037)^18 = 0.507  So after 18 hits you will get about half the targets as B Kills, of which ~half would have been A kills.

 

But this is assuming that the hits are randomly placed across the surface.  If they all miss the pilot, engine or fuel tank, being aimed at the wing, the shots have a 0.011 p of getting a B Kill. (At best - probably lower since "structures" in the report includes everything that is not E,P or F).  (1-0.011)^18 =  0.819 so about 18% of the targets, again about half being A kills. (Probably from damaging control systems).

 

Essentially, according to a800394, 50 cals are just not as damaging as you appear to think. 

 

  

 

 

[alpino]

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
 

[BCI-Nazgul]

3 hours ago, unreasonable said:

Relative "size: depends on the aspect. Here is a graph from some old tests of LAA vs planes (old DM) where I constructed an index of size from a behind, slightly below and to the side angle, since that was when most planes were being hit.  I used the IL-2 viewer to take screenshots of the models and counted pixels in GIMP.  The P-47 is about 50% bigger than the 109s from this angle and was getting hit about 50% more often.  Do not guess - measure.

 

If you wanted to construct a kill probability table for hits similar to those in the report for another fighter, you need to know the % of the total aspect presented by the pilot, engine and fuel tank from the angle used in the report for the P-47.  The pilot is clearly a proportionately bigger target in a smaller plane, but that might not be true of the other systems.  You would have to make a couple of extra assumptions about vulnerability, armour etc as well, in line engines being more fragile, for instance.  

 

 

 

 

I think you mistook the "size" part of my comment a little wrong.  I wasn't referring to hit probabilities.  Your probabilities are kill probabilities based on number of hits sustained.   Whether or not you can hit a target and with how many rounds is another subject.   I meant larger aircraft generally require more hits to shoot down because the amount of important "stuff" is spread out more AND/OR it's larger and harder to destroy.   The wing is a good example.   Obviously a 6" hole in a wing that is 15 feet long and 4 feet wide is a much bigger deal than the same hole in a wing that is 30 feet long and 8 feet wide (assuming no critical.)   As we know, the P-47 was exceptionally tough plane.   It's also huge compared to other fighters.  I'm sure a good part of that toughness comes from sheer size of the various components required for such a large plane.   It's tough in game and that lines up with historical accounts and I think with % of losses (if I remember right.)   On purely statistical basis (averaging over say 1000 shoot downs) I wouldn't expect a ME-109 or P-51 to be able to withstand nearly as many hits as a P-47 and survive.

 

Your link was interesting.  A quick browse pretty much matched up with my expectations, however, a big problem is that all the numbers for the .50 M2 are for API rounds.   I don't think we have those in game, so I have no idea if any of the numbers they provide are useful other than to show that the 20mm does a lot more damage per hit.  Also, I'd never heard of a .60 machine gun, but they seem quite good.  It's also shame they don't provide numbers for any smaller aircraft.

[unreasonable]

The key point I wanted to make is that whether you are looking p of hits p of kills from a hit, the German fighters were not "half the size of or less" than the P-47. They were about 2/3 of the size, depending on the angle.

 

I agree about your general toughness points in principle - although it is of note that the more overpowered a shell is per hit, the more important not being hit at all becomes. If the game's hits do too much damage, that reduces the benefits of being large, without altering the downside. Which is certainly where we were with older DM versions.

 

I would not expect API-T to have significantly different results to ball except in the case of a hit to an area leaking fuel, for which you have to make the separate compound damage assessment anyway.  It is not an explosive bullet, has pretty much the same ballistics. In terms of what we have in the game - the test of what is an incendiary is how many fires it causes, not what it says in the GUI.   

 

Having other planes tested would be great, but I suppose they just tested what was made available. At least it allows us to have a look at the comparative lethality of of some of the rounds that are in the game, or very similar, vs one of the planes in the game. So it is a good reference point from which to make some educated guesses.

[Aurora_Stealth]

@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.

[RedKestrel]

5 hours ago, unreasonable said:

The key point I wanted to make is that whether you are looking p of hits p of kills from a hit, the German fighters were not "half the size of or less" than the P-47. They were about 2/3 of the size, depending on the angle.

 

I agree about your general toughness points in principle - although it is of note that the more overpowered a shell is per hit, the more important not being hit at all becomes. If the game's hits do too much damage, that reduces the benefits of being large, without altering the downside. Which is certainly where we were with older DM versions.

 

I would not expect API-T to have significantly different results to ball except in the case of a hit to an area leaking fuel, for which you have to make the separate compound damage assessment anyway.  It is not an explosive bullet, has pretty much the same ballistics. In terms of what we have in the game - the test of what is an incendiary is how many fires it causes, not what it says in the GUI.   

 

Having other planes tested would be great, but I suppose they just tested what was made available. At least it allows us to have a look at the comparative lethality of of some of the rounds that are in the game, or very similar, vs one of the planes in the game. So it is a good reference point from which to make some educated guesses.

I think it's reasonable to assume that API is not modeled in game. I believe if they were going so far as to model the incendiary effect of the ammunition, they would put it in the GUI as such - why wouldn't they?

It also appears that while engine fires with the M2 ball ammo are not uncommon, it's pretty rare to get a fuel tank fire. If someone asked me if API was modeled based on ammunition effects, I would say no. It's possible the likelihood of fire is increased for the ball ammo relative to what it would be IRL in order to compensate for the lack of API but I think this is unlikely - more likely, we are just seeing what the devs model as the probability of straight AP rounds starting a fire.

I think one problem with any API modeling that does happen in the future is that people are already over-estimating the impact of API shells on aircraft structure. People seem to conflate incendiary effects with explosive effects when the two are separate. 

In any case they are working on the fuel systems as per the dev diary, so if that work includes modeling incendiary effects then we will soon see what it will do. I don't think I've seen an official comment from the devs about modeling API, only about modeling fuel systems better.

But honestly I only expect it to increase the likelihood of fire and decrease the likelihood of a pilot kill somewhat as the API rounds should have less penetration. I don't think we'll see a night and day difference from what we have now.

[Caudron431]

12 hours ago, 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
 

 

 Nice pics, really interesting indeed. Exit holes clearly showing explosive incendiary devices not available during WW2 though.

 

The most interesting for the thread are the entry holes and the slight deformation of the wing at the impact point, it's not as neat entry holes as i thought they would be.  If assuming that the exit hole is often dirtier than the entry ones this should cause penalty excess drag for sure (not talking about the amount which could be calculated by an engineer). 

 

 

I cannot believe  .50 cal holes or any sort of holes (even the most neat ones) in a wing would not cause noticeable performance loss and noticeable handling changes (while the aircraft could still be controllable more easily than if it was affected by big holes in its wings) . In the test provided by OP a big part of the ammo hits the wing surface causing nothing speed wise.

 

That can simply not be correct if its verified.

 

Civilian pilots know they can add speed by just cleaning the surface of the wing, even more if you repaint it, again some more if you fill holes and little impacts.

No excess drag penalty and loss of speed (and balance) from  50cal impacts causing  holes (some neat some dirty) in a wing, it's impossible imho, especially when you consider that in the test provided they are not hit by 4 or 5 but by 20 or more. If the bullet goes through the wing it damages the wing two times. At a certain point, it become a lot of excess drag, it should be taken into account imho.

 

Strange.

 

PS question for experts:  Is it correct to assume that if hit from uperside to the underside the dirty exits from the ball bullets happen there where the wind pressure is higher thus causing more drag than in the reverse situation? Or to simplify what side of a wing creates more drag if damaged, if there is any difference at all?

 

Edited June 22, 2020 by Caudron431Rafale
poor english sorry

[unreasonable]

4 hours ago, RedKestrel said:

I think it's reasonable to assume that API is not modeled in game. I believe if they were going so far as to model the incendiary effect of the ammunition, they would put it in the GUI as such - why wouldn't they?

 

Two thoughts, otherwise agree completely with yr post:

Given that USAF beltings were mixed, even if the game explicitly modeled API only a proportion of hits would have any additional incendiary effect. Not sure if it would be worth the game trying to "remember" whether each round fired is AP/ball/API etc when shot, instead of giving a composite probability for incendiary outcomes after hit recognition has taken place. There could be thousands of rounds in the air at a given moment.  By composite probability, I mean that if you added API as one in three in the "belting", you would get an increase in the probability of a fire, for any hit where fire is possible, equal to 1/3 of the difference between the probability of ball causing a fire and API causing a fire.

 

The issue is whether the current game probabilities of hits causing fires match up to the USBL's estimates for API-T. If game 50 cals already cause fires at that rate, or even at a lower rate consistent with a mixed belt as described above, then the game is already modeling API-T, even if the developers had not intended so to do!  In which case they could add a little coloured bullet in the GUI and the placebo effect would take care of the rest.

 

(I am getting a little cynical in my old age...  )

 

 

 

 

[alpino]

4 hours ago, Caudron431Rafale said:

 Nice pics, really interesting indeed. Exit holes clearly showing explosive incendiary devices not available during WW2 though.

 

The most interesting for the thread are the entry holes and the slight deformation of the wing at the impact point, it's not as neat entry holes as i thought they would be.  If assuming that the exit hole is often dirtier than the entry ones this should cause penalty excess drag for sure (not talking about the amount which could be calculated by an engineer). 

 

 

I cannot believe  .50 cal holes or any sort of holes (even the most neat ones) in a wing would not cause noticeable performance loss and noticeable handling changes (while the aircraft could still be controllable more easily than if it was affected by big holes in its wings) . In the test provided by OP a big part of the ammo hits the wing surface causing nothing speed wise.

 

That can simply not be correct if its verified.

 

Civilian pilots know they can add speed by just cleaning the surface of the wing, even more if you repaint it, again some more if you fill holes and little impacts.

No excess drag penalty and loss of speed (and balance) from  50cal impacts causing  holes (some neat some dirty) in a wing, it's impossible imho, especially when you consider that in the test provided they are not hit by 4 or 5 but by 20 or more. If the bullet goes through the wing it damages the wing two times. At a certain point, it become a lot of excess drag, it should be taken into account imho.

 

Strange.

 

PS question for experts:  Is it correct to assume that if hit from uperside to the underside the dirty exits from the ball bullets happen there where the wind pressure is higher thus causing more drag than in the reverse situation? Or to simplify what side of a wing creates more drag if damaged, if there is any difference at all?

 

at first I thought the larger holes at the exit were due to bullets tumbling after the first impact, specially the two bigger ones, unfortunately I couldn't find the specific type of ammo used.
I would expect explosive ammo to detonate right at the entry or maybe inside the wing though.

searching at the cbc page (who produces the ammo used here by the military) I couldn't find any .50 HEI: https://www.cbc.com.br/produtos/categoria/municoes-para-fuzis-metralhadoras-e-medios-calibres/linha/municoes-para-fuzis-e-metralhadoras/?calibre[]=127-x-99mm-50
 

Edited June 22, 2020 by alpino
found more data

[BCI-Nazgul]

As far as API vs. AP,  I'm pretty sure I'd have substantially more kills if leakers turned into burners.   I'm thinking the first round in a burst would only punch a hole but succeeding rounds would have a pretty good chance of lighting the now leaking fuel or oil.  A burner isn't going to continue fighting for long before they are definite kill (or as the study says an "A" kill.)    A leaker can continue fighting for a long time and probably get home as well.

 

One other point that some people aren't taking into account in these .50 discussions:  There is a chance that even an AP round could tear off a big section of skin if it comes in at a flat angle and hits a seam like a can opener.   Not a big chance, but it could happen.  Or the round could hit something inside the plane and knock it though the skin whole or in pieces.  From what I've read the skin just isn't that strong because it has to be as light a possible.   Just some food for thought.

Edited June 23, 2020 by BCI-Nazgul

[JG13_opcode]

2 hours ago, unreasonable said:

Not sure if it would be worth the game trying to "remember" whether each round fired is AP/ball/API etc when shot, 

 

FWIW you could code this in a very performant manner.  If they haven't modeled incendiary rounds it's not because of performance.

[alpino]

also interesting to see the kill here between 3:42 and 3:49, you can see some nasty damage to the left wing followed by loss of control 

 

[unreasonable]

2 hours ago, BCI-Nazgul said:

As far as API vs. AP,  I'm pretty sure I'd have substantially more kills if leakers turned into burners.   I'm thinking the first round in a burst would only punch a hole but succeeding rounds would have a pretty good chance of lighting the now leaking fuel or oil.  A burner isn't going to continue fighting for long before they are definite kill (or as the study says an "A" kill.)    A leaker can continue fighting for a long time and probably get home as well.

 

With the upcoming changes to the fuel systems, you might see fewer leakers? I have always wondered why fuel tanks were so easily holed in BoX,   I suspect simply because it is a cool graphical effect.  US planes had self sealing tanks intended to be proof against 50 cal hits (unless you copped a lot in one area). Not sure about the Germans and Russians.  Additionally wing tanks were, I believe, usually emptied first. 

 

If you model incendiary effects while the fuel tanks are modeled as though they were non-self sealing, you will get silly results. (Except in FC, as that is how it was in 1918). 

 

 

 

 

[BCI-Nazgul]

Well, the Japanese planes were "burners" for sure.  They did not have self-sealing tanks.  German and Russian planes I don't know about.  I'm thinking at least the Germans did have self-sealers because they weren't known as "burners" like the Japanese planes.

[Caudron431]

8 hours ago, BCI-Nazgul said:

As far as API vs. AP,  I'm pretty sure I'd have substantially more kills if leakers turned into burners.

After quickly testing 50. cals on several AI drones recently i noticed some are very prone to taking fire and rather quickly. Last couple of experiments made yesterday i think API could already be modelled in game: the fuel systems are perhaps modelled on some ac and not on some other types yet . The Fw190A8 for instance took fire almost everytime with reasonnable amout of gunfire from the Poney 4x50 cal, convergences between 150 and 250m.

 

I was impressed to see them burn three times in a row without effort (maybe luck?).

 

On the other hand shooting the Spitfire with the same weapons ( as we know fuel tank is in front of the cockpit) never took fire but leaked and went down PK usual style. Experimenting now on the 109, in a fight, it took a lot of .50 cal gunfire  and eventualy went down leaking severly no fire but dark smoke, PK, and with outer part of a wing falling of...

 

Apart from the drag pb your interesting test seems to show, the .50 cals are already a more than decent weapon IMO even only used by four. Again just my impressions.

Edited June 23, 2020 by Caudron431Rafale

[BCI-Nazgul]

Was it an engine fire or a fuel tank fire?  Engine fires are much more likely.

[Caudron431]

Fw190A8: fuel tank fire 3 times in a row yesterday!

 

!!!Edit: ok re checked the tracks, "only" two tank fires and one of the three was engine fire, sorry. Still it's three fires ! It was quick to recheck though, all three Fockes AI  veteran 30% fuel, start 1500m, against player P51 start 900m, 500l fuel,  4X.50cal, default gunsight.

 

First kill after 2 min in combat, second one 4 min, third one 2 min 02. All three FW190A8 downed in the first attempt. Not bad considering i'm not a a very good shot.

 

 

 

Edited June 23, 2020 by Caudron431Rafale

[357th_KW]

6 hours ago, unreasonable said:

 

With the upcoming changes to the fuel systems, you might see fewer leakers? I have always wondered why fuel tanks were so easily holed in BoX,   I suspect simply because it is a cool graphical effect.  US planes had self sealing tanks intended to be proof against 50 cal hits (unless you copped a lot in one area). Not sure about the Germans and Russians.  Additionally wing tanks were, I believe, usually emptied first. 

 

If you model incendiary effects while the fuel tanks are modeled as though they were non-self sealing, you will get silly results. (Except in FC, as that is how it was in 1918). 

 

 

 

 

 

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.

 

 

1 hour ago, Caudron431Rafale said:

After quickly testing 50. cals on several AI drones recently i noticed some are very prone to taking fire and rather quickly. Last couple of experiments made yesterday i think API could already be modelled in game: the fuel systems are perhaps modelled on some ac and not on some other types yet . The Fw190A8 for instance took fire almost everytime with reasonnable amout of gunfire from the Poney 4x50 cal, convergences between 150 and 250m.

 

I was impressed to see them burn three times in a row without effort (maybe luck?).

 

On the other hand shooting the Spitfire with the same weapons ( as we know fuel tank is in front of the cockpit) never took fire but leaked and went down PK usual style. Experimenting now on the 109, in a fight, it took a lot of .50 cal gunfire  and eventualy went down leaking severly no fire but dark smoke, PK, and with outer part of a wing falling of...

 

Apart from the drag pb your interesting test seems to show, the .50 cals are already a more than decent weapon IMO even only used by four. Again just my impressions.

 

I ran some testing in 4.006 against the P-38 and B-25 sitting stationary at around 80-90 yards.  The first burst of 2-4 rounds (aimed at the wing fuel tanks) almost always causes a fuel leak.  Starting the tank on fire averaged about 33 rounds on the P-38 and 39 on the B-25.  We clearly have plain AP and AP-T in game.

 

Based on the stationary target testing I did in 4.006, the Spit 9 and 190A8 are the two most vulnerable aircraft in BoBP from the rear.  The 109s were the strongest by a huge margin - you can make them burn but it often takes 100+ rounds on target from a rear angle.  Here's the quick and dirty video I put together in 4.007:

 

 

 

[Aurora_Stealth]

I'd just like to clear something up while we're on topic here as I've been taking some strange comments from players online who think that I'm deliberately trying to portray things to cause problems for the Allied side... I'm all for authenticity on both sides that's what gives the game its credibility however people have to be realistic as to what's achievable in a game - especially when people have such high expectations from online gameplay.

 

No one in their right mind is saying that no aerodynamic effect would occur when using the .50 calibre because it is not a cannon, some speed loss would obviously occur when enough bullets are soaked up. The question is how much so and is it really significant enough to demand the team to spend further time on an already onerous level of detail.

 

The team has limited resources and time, you guys want the new Normandy map and all those aircraft plus every other expansion to be exactly as you each desire it.

 

We're also not saying "every" .50 calibre hole recorded in combat would have been neat, its a little more complex than that and other effects occur but they tend to puncture skin on average (ball ammo / API).. not so much deform or open large areas of it (modern APEI) - there are always outliers if you search hard enough but the game cannot give you every variation exactly.

 

With modern explosive ammunition (APEI) and special filler types these characteristics on the .50 calibre can be altered today (including the timing and fusing of ammunition to explode at a certain point past its impact. They can be engineered to explode early on so to damage skin, or delay and explode further inside but this happened after WW2 regarding the .50 calibre.

 

We need to be realists here - the data transfer involved in calculating each machine gun bullet and its aerodynamic effect would be horrendous for everyone online so that's not a direction anyone is going to like. Those type of changes are unlikely to change the result of an aircraft being shot down or not simply because it is ~7 to 10mph slower than it was from accumulating 20 to 30 hits of machine gun ammo. Much more significant is control damage and stability which is already modelled.

 

I'd be very surprised if every bullet (firing 750 - 800 rounds in a minute) of a gun could ever be calculated individually in its exact aerodynamic effect. It's a bit much to expect this, and more likely it is a function of accumulated damage as a larger total calculation which for data transfer is efficient and makes sense.

 

11 hours ago, alpino said:

also interesting to see the kill here between 3:42 and 3:49, you can see some nasty damage to the left wing followed by loss of control 

 

 

I like the video, and the scene chasing the '109's makes me smile. It looks like the pilot is desperately trying to snap roll but then loses balance and control because of the damage.

 

Without meaning to be cynical - and in relation to what we're discussing - its the imbalance in aerodynamics or loss of control not the performance or speed loss that causes the biggest problems here with the .50 calibres. Note the pilot cannot hold the maneuver properly because one side is hit / imbalanced, not because the aircraft is so punctured that it lost all its speed (its still moving relatively quick even in maneuvres for a good amount of that video). I'd suspect that the blown left radiator at 3:40 has just caused a load of aerodynamic drag on one side of the aircraft, due to the heat and disruption to the airflow which is shifting around and also clouding over the left hand side of the fuselage and tail - causing imbalance and stalling it. Adding any kind of strong evasive maneuver into that situation, such as a snap roll as he does.. will make that much worse and it helps to initiate that ensuing spin.

 

It's hard to tell if that is in fact ripped skin damage on the edge of the left wing (its still possible), its pretty obscure and it could be the aileron.

 

Cheers,

Edited June 23, 2020 by Aurora_Stealth

[HR_Tumu]

M2 need a bit of love

 

Edited June 23, 2020 by HRc_Tumu

[HR_Tumu]

last bf on this video must be bugged

[MattS]

The problem with the M2 and other 12.7mm guns in the game is that they are rigidly connected to the airframe, and crowded in among other similar guns. This limits their freedom of individual expression and makes them feel like just a number, another cold dead machine that nobody loves, which decreases their performance.

 

To really live up to their potential they need to be mounted on a pintle all by themselves, where they can aim in all directions and enjoy the breeze and the personal touch of a handsome young gunner. In that situation they can absolutely shred.

[Aurora_Stealth]

Haha! let that M2 go free or mount it on a horse with no name ?

 

I think that's also the story with many of the aircraft too, they all have big personalities which collide and it can feel a bit bruising at times.