Airplane FM after being damaged.

[LukeFF]

12 minutes ago, II./JG77_motoadve said:

Just get good hits and leave, they are damaged and go down.

 

That's the key right there - instead of hammering away with all your ammo until a wing falls off, move on once they are showing obviously significant damage.

Edited January 16, 2019 by LukeFF

[Mad_Mikhael]

6 hours ago, JG7_X-Man said:

To me the biggest issue is the DM! I (like many of the ppl here) read books on the subject and everything I read says that typical a 3 sec burst of fire that hit is sufficient to bring down a fighter. We are not talking about the 30mm the G-6 had in late '43 either.

 

So the issue here is why after this last update does it takes 1/2 my ammo to bring down a yak (...maybe a 109 in your case)?

 

My only guess is in creating the DM of the P-47, they porked the DM of all other aircraft.

 

I know you already have my BOK, BOM, BOS and BOBP money so you don't care developers - but you might what to fix this.

 

I get the fact that it would not be much fun for such realism, but 45 rounds hitting a fighter aircraft anywhere and it is still flyable is absurd and almost comical. If you are going to call this an arcade game, that is one thing - but an semi authentic simulator, I have to beg to differ on that.

Just for laugh.

MG 151/20 spits 11 rounds per second, so your 3 seconds burst is 33 rounds. It's close to those 45, just 1 second longer burst ?

 

Being serious, II./JG77_motoadve is right.

Edited January 16, 2019 by =LG=Mad_Mikhael

[JtD]

While I managed to pump 45 hits into a fighter before it went down, I rarely ever need more than 10 to achieve the same thing. 45 is just overkill and has nothing to do with the damage model. A claim like that is absurd and almost comical.

[=EXPEND=13SchwarzeHand]

Are you talking about bullets in general or 20mm?

20-40 bullets per plane is a realistic number. Look at any server and check out the stats for fighters shooting down fighters. This is exactly the number you will find.

[JG7_X-Man]

I agree with you guys - I am just saying the LaGGs, La-5s and Yaks have fuel tanks in the wing, 1 in each wing root section and another mid wing section. So any aircraft you see flying with big gaping holes (cannon hits) in the wing, is a DM error. That aircraft should either be on fire or a file ball. With 45 rounds hitting any aircraft it should be already on it death throes.

 

I would say the smaller holes from 7.92mm hits would be OK because of the version of aircraft with self -sealing tanks. However, we can all agree nothing is sealing a 20mm hit.

Edited January 18, 2019 by JG7_X-Man

[unreasonable]

3 hours ago, JG7_X-Man said:

I agree with you guys - I am just saying the LaGGs, La-5s and Yaks have fuel tanks in the wing, 1 in each wing root section and another mid wing section. So any aircraft you see flying with big gaping holes (cannon hits) in the wing, is a DM error. That aircraft should either be on fire or a file ball. With 45 rounds hitting any aircraft it should be already on it death throes.

 

I would say the smaller holes from 7.92mm hits would be OK because of the version of aircraft with self -sealing tanks. However, we can all agree nothing is sealing a 20mm hit.

 

It can easily be just a mismatch of the graphics that you see with the damage. The graphics overlay for holes is only generally related to the location and type of damage inflicted. One cannon hit on a wing can led to anything from a few small splinter holes to two large holes and lots of small ones: I believe the graphic simply represents the overall level of damage taken by the component. In my own subjective view, based on watching P-47s being hit in my DM tests, the holes are sometimes rather overdone compared to what I suspect would have been visible.

 

As for the last comment this is usually but  not always true: even direct 20mm hits on fuel cells can indeed be sealed and will not always cause leaks or fires, at least on the US tanks tested in a800109 "Effectiveness of incendiary ammunition against  aircraft fuel tanks" available online. It depends on the functioning of the fuze and the velocity of the hit.  Additionally splinters from 20mm hits near the tank should rarely cause leaks: the metal content of a typical 20mm HE shell is only about 2.5 times that of a 50 cal bullet, once this has splintered in many parts only rarely would a splinter be large and irregular enough to defeat self sealing designed to defeat 50 cal hits.  (In contrast, 20mm hits to the inner wing section of P-47s regularly cause fuel leaks in the game).

 

I have no idea how effective Soviet self sealing tanks were, BTW.

 

 

Edited January 18, 2019 by unreasonable
correct error

[Raymondo77]

14 hours ago, unreasonable said:

As for the last comment this is usually but  not always true: even direct 20mm hits on fuel cells can indeed be sealed and will not always cause leaks or fires, at least on the US tanks tested in a800109 "Effectiveness of incendiary ammunition against  aircraft fuel tanks" available online. It depends on the functioning of the fuze and the velocity of the hit.  Additionally splinters from 20mm hits near the tank should rarely cause leaks: the metal content of a typical 20mm HE shell is only about 2.5 times that of a 50 cal bullet, once this has splintered in many parts only rarely would a splinter be large and irregular enough to defeat self sealing designed to defeat 50 cal hits.  (In contrast, 20mm hits to the inner wing section of P-47s regularly cause fuel leaks in the game).

 

 

Weren't the two 20mm shells of American type?

How does that BRL test result compare to a hit from German mineshells, or British SAPI rounds?

 

Spoiler

 

 

[unreasonable]

5 hours ago, Raymondo77 said:

 

Weren't the two 20mm shells of American type?

How does that BRL test result compare to a hit from German mineshells, or British SAPI rounds?

 

  Reveal hidden contents

 

 

 

I would not expect the results to be radically different for a German 20mm mineshell: it would still have to actually hit the relevant area at the required velocity and detonate at the right time: and the blast effect from outside the tank will not necessarily puncture it unless it generates a nice big piece of debris that hits the fuel cell. You can detonate HEI 20mm taped against the outside wall of a fuel cell and it does not lead to a penetration.

 

The US tests included firings of 30mm  German HE from a MK108 in their experimental set up: of 15 hits they had 8 perforations, of which 7 led to fires.  So we can safely expect 20mm mineshells to generate proportionately far fewer holed tanks than that.

 

It is a really interesting report: people should read it. 

 

 

 

 

 

[Raymondo77]

13 hours ago, unreasonable said:

 

I would not expect the results to be radically different for a German 20mm mineshell: it would still have to actually hit the relevant area at the required velocity and detonate at the right time: and the blast effect from outside the tank will not necessarily puncture it unless it generates a nice big piece of debris that hits the fuel cell. You can detonate HEI 20mm taped against the outside wall of a fuel cell and it does not lead to a penetration.

 

To be precisely, none of the M97 20mm rounds tested have punctrued the fuel tank nor caused leakage:

https://imgur.com/a/0RK8Xe7

 

The German 20mm mineshell is expected to yield a markedly different test result, has it contain ~ 5 times more high explosives as the M95 HEI shell.

The M97 contain 85,4 grains or 5,5 gms of Tetryl, a mineshell 18,6 gms of PETN. Tetryl has an TNT equivalency of 1.25, (6,875 gms) and PETN 1.66. (30,876 gms)

 

M97 Flash radiograph:

https://apps.dtic.mil/dtic/tr/fulltext/u2/147191.pdff#page=14

 

German 20mm Flash radiograph:

http://history.amedd.army.mil/booksdocs/wwii/actvssurgconvol2/chapter4.htm

 

"When an Oerlikon shell burst, it fragmented into thousands of pieces which varied in weight from less than 1 mg. to 20 gm. (fig. 140). However, the largest number of "effective" Oerlikon shell fragments bursting in an area 5 feet in diameter and capable of causing incapacitation to the person exposed was 260. The majority of those 260 fragments weighed between 10 and 50 mg., and their velocity varied between 400 and 600 m.p.s. (meters per second)."

 

14 hours ago, unreasonable said:

It is a really interesting report: people should read it.

 

At any rate, but one should be careful not to draw generalized conclusions. However, I still expect the chances to puncture a fuel tank (by shell burst) was distinctly higher with the mineshell than it is with the M97 shell.

[unreasonable]

15 hours ago, Raymondo77 said:

 

To be precisely, none of the M97 20mm rounds tested have punctrued the fuel tank nor caused leakage: etc 

 

"The majority of those 260 fragments weighed between 10 and 50 mg., and their velocity varied between 400 and 600 m.p.s. (meters per second)."

 

I am not sure why you think a 10-50 mg splinter should cause a leak in a cell designed to self seal when hit by a 45-50 g bullet travelling at much the same speed. That is 45,000 to 50,000 mg. 

 

76g of metal is less than the weight of two  50 cal rounds (about 45g each).  So from splinter damage, there would have to be an irregular and very large splinter to breach a  self sealing tank, that just happened to go in the right direction.  Not impossible but extremely unlikely.

 

What about blast? It all depends on whether the explosion is in a confined space of the right size, and that depends on the fuse functioning properly and not being broken off or triggered by the skin or the aircraft or a protective plate. Possible but will not always happen.

 

The point you have not addressed at all is that the US reports included firings of 30mm mineshells: if these had a ~50% chance of causing a leak and fire when fired at the area of a fuel cell, surely you would expect 20 mm mineshells with 22% of the HE - and equivalently less metal -  to cause leaks and fires far less often? If not, why not?

 

"At any rate, but one should be careful not to draw generalized conclusions. However, I still expect the chances to puncture a fuel tank (by shell burst) was distinctly higher with the mineshell than it is with the M97 shell."

 

Some generalized conclusions are more equal than others?   Note that in table 1 of the firing test results, 14 M97 hits yielded 9 fires, while 15 30mm mineshell hits yielded only 7. So I believe the US test disproves this hypothesis quite clearly.   

 

 

 

    

Edited January 20, 2019 by unreasonable

[Raymondo77]

10 hours ago, unreasonable said:

 

76g of metal is less than the weight of two  50 cal rounds (about 45g each).  So from splinter damage, there would have to be an irregular and very large splinter to breach a  self sealing tank, that just happened to go in the right direction.  Not impossible but extremely unlikely.

 

What about blast? It all depends on whether the explosion is in a confined space of the right size, and that depends on the fuse functioning properly and not being broken off or triggered by the skin or the aircraft or a protective plate. Possible but will not always happen.

 

A single fragment of 50 mg, traveling at 400 and 600 mps should be enough to puncture the fuel tank. Now, the blast that comes along, would and could (in close proximity) tear a much bigger hole. See e.g. BRL study "Effect of Blast on Aircraft Fuel Tanks", 1950.

 

10 hours ago, unreasonable said:

The point you have not addressed at all is that the US reports included firings of 30mm mineshells: if these had a ~50% chance of causing a leak and fire when fired at the area of a fuel cell, surely you would expect 20 mm mineshells with 22% of the HE - and equivalently less metal -  to cause leaks and fires far less often? If not, why not?

 

Why should I? You claimed by stating that the "typical" 20mm HEI round would not puncture the fuel tank, whitout specfiy the exact type of round being tested, and that the German 20 mineshell shared the same fate. The 30mm Mineshell is is therefore out of equation.

 

Sorry, where you pulling this numbers from?

 

10 hours ago, unreasonable said:

Note that in table 1 of the firing test results, 14 M97 hits yielded 9 fires, while 15 30mm mineshell hits yielded only 7. So I believe the US test disproves this hypothesis quite clearly.   

 

It doesn't disproves quite anything. Only that you cannot read properly...

 

The 20mm M97 was fired 14 times; 10 times the fuel tank was perforated; 9 out of 10 time it caused a fire.
The German 30 mm was fired 15 times, 8 times the fuel tank was perforated; 7 out of 8 time it caused a fire.
See: https://apps.dtic.mil/dtic/tr/fulltext/u2/a800109.pdf#page=41

 

Now, what happened to the other shots? They either failed to penetrate, ricochet off or were duds.

Both rounds have a 90% chance of causing a fire when penetrating the fuel tank.

Edited January 20, 2019 by Raymondo77

[unreasonable]

7 hours ago, Raymondo77 said:

 

A single fragment of 50 mg, traveling at 400 and 600 mps should be enough to puncture the fuel tank. Now, the blast that comes along, would and could (in close proximity) tear a much bigger hole. See e.g. BRL study "Effect of Blast on Aircraft Fuel Tanks", 1950.

 

 

A 50 caliber bullet weighs 45-50 grams. How on earth do you think that a tank designed to self seal when hit by this bullet - typical impact speeds of which would be usually more than 400-600 m/s - would fail to self seal when hit by one splinter weighing one thousandth of such a bullet. Please give some evidence for this assertion.

 

The 30mm mineshell data is not "out of the equation": it illustrates that mineshells are not the be all and end all some appear to imagine: the figures are from table 1 in the report - as I said in my previous post.  These are the experimental facts.

 

Yes, both rounds have a very high probability of causing fires if they penetrate, or breach the wall of the cell from the outside through blast or fragmentation: but the point is that they both only this ~50% of the time in the test.  It seems highly likely to me 20mm mineshell is less likely to breach the cell wall than a 30mm mineshell with over four times the HE and fragment weight.

 

The ratio of fires/hits was not 90% for the M97: you are only looking at the hits for the maximum impact speed (2050 f/s). For all speeds listed it is 25 hits excluding duds, leading to 17 peforations, (68%), and 13 fires (76% of perforations).  As I said in my initial post responding to X-man: not all 20mm penetrations fail to self seal. That is a simple fact as shown by the experimental data.

 

As for  "BRL study "Effect of Blast on Aircraft Fuel Tanks", 1950." I am sure that this is very interesting, but since Google gives no hits for this and you do not give a reference number or a link, perhaps you could post the zip file here.

 

 

 

 

 

 

 

[Raymondo77]

11 hours ago, unreasonable said:

 

A 50 caliber bullet weighs 45-50 grams. How on earth do you think that a tank designed to self seal when hit by this bullet - typical impact speeds of which would be usually more than 400-600 m/s - would fail to self seal when hit by one splinter weighing one thousandth of such a bullet. Please give some evidence for this assertion.

 

The M20 API-T projectile tested weights exactly 40.11 gms, the M23 Incendiary is unknwon but at 3400 ft/s its likely to have much less than 40 gms. And source is given, fragments of >50gms could defeat the fuel tank under fair cirucumistances. You made that claim on the first place that the German 20mm HEI would fail, whitout presenting a source. Now I should provide a source to disprove your shenanigans? Make up your mind.

 

12 hours ago, unreasonable said:

The 30mm mineshell data is not "out of the equation": it illustrates that mineshells are not the be all and end all some appear to imagine: the figures are from table 1 in the report - as I said in my previous post.  These are the experimental facts.

 

Yes, both rounds have a very high probability of causing fires if they penetrate, or breach the wall of the cell from the outside through blast or fragmentation: but the point is that they both only this ~50% of the time in the test.  It seems highly likely to me 20mm mineshell is less likely to breach the cell wall than a 30mm mineshell with over four times the HE and fragment weight.

 

Your talk of the 30mm Mineshell is completely irrelevant, as you made that assertion about the German 20mm mineshell based on the M97 test results. A charge of 1/16 pound (or 28.3 gms) of TNT placed outside at the center of a B-17 fuel tank was found to be enough to crack the fuel tank and cause leakage:

 

Spoiler

https://imgur.com/a/SEQk4UB

 

That's the same amount of TNT packed inside a 20mm mineshell.

 

12 hours ago, unreasonable said:

The ratio of fires/hits was not 90% for the M97: you are only looking at the hits for the maximum impact speed (2050 f/s). For all speeds listed it is 25 hits excluding duds, leading to 17 peforations, (68%), and 13 fires (76% of perforations).  As I said in my initial post responding to X-man: not all 20mm penetrations fail to self seal. That is a simple fact as shown by the experimental data.

 

That makes no sense to me. Why you are adding the different firing ranges together?

 

Table 1:

P-38, Fring from Front, Above; Impact angle: 13°

20 M97 HEI, Velocity: 2050 ft/s, Range:    500 yards: 14 Hits, 10 Perforations, 9 Fire = 90%
20 M97 HEI, Velocity: 1580 ft/s, Range:  1000 yards:   9 Hits, 1 dud, 7 Perforations, 3 Fire = 43%
20 M97 HEI, Velocity:   760 ft/s, Range:  2000 yards:   6 Hits, 1 dud, 5 Perforations, 1 Fire = 20%

 

The author states: "A projectile may impact the projected area and not perforate a tank due to ricochet or insufficient remaining velocity."

 

I'm not going to give you anything, I'm done here. The PDF is reserved for the Developers if they ask me personally.

Have a good day.

[unreasonable]

18 minutes ago, Raymondo77 said:

 

The M20 API-T projectile tested weights exactly 40.11 gms, the M23 Incendiary is unknwon but at 3400 ft/s its likely to have much less than 40 gms. And source is given, fragments of >50gms could defeat the fuel tank under fair cirucumistances. You made that claim on the first place that the German 20mm HEI would fail, whitout presenting a source. Now I should provide a source to disprove your shenanigans? Make up your mind.

 

What on earth is the matter with you?  I gave a source:  "a800109 "Effectiveness of incendiary ammunition against  aircraft fuel tanks" available online" it is right there in my post with the extract I provided. Google it and you get taken straight to the original. 

 

I did not say or imply that the German HEI - or any other shell - would always fail: I simply asserted that some 20mm cannon hits can indeed be sealed, and presented proof in the form of a quotation from people who know what they are talking about.  And then there are the tables which show that not all hits penetrate and not all penetrations cause fires. These are simple and indisputable facts. That is also true for mineshells: of any size.

 

It is good that you are done here. 

 

 

 

 

 

[JtD]

 

21 hours ago, Raymondo77 said:

A single fragment of 50 mg, traveling at 400 and 600 mps should be enough to puncture the fuel tank.

 

Even if so (unlikely in case of protected tanks), (split) seconds later the self sealing qualities of a decent WW2 fuel tank will have closed the hole, which would be ridiculously small. A 50mg fragment of steel is a size of about a 2mm diameter ball, and self sealing tanks had no problem sealing holes ten times the size. Ineffectiveness of small rounds is why gun size went up over the course of the war.

 

The minimum you need to have a real effect is about a hundred of these fragments and a supporting gas shock nearby - i.e. the exploding 20mm round in very close proximity to the tank.

 

For what it's worth, the 20mm shell you referred to producing 260 fragments of 10-50mg is a standard HE shell which only contains 3.6g of explosives, which makes it kind of comparable to the US rounds.

[=FEW=ayamoth89]

in this video you can see 3 cases where planes fly very fast and well despite very bad damages. Just for the record, in the two FW clips I used 4 cannons version. 

 

https://youtu.be/wNuDt2ar2g8

[JG7_X-Man]

14 hours ago, =FEW=ayamoth89 said:

in this video you can see 3 cases where planes fly very fast and well despite very bad damages. Just for the record, in the two FW clips I used 4 cannons version. 

 

https://youtu.be/wNuDt2ar2g8

 

Nice video and shots! Thanks for proving our point with evidence the damage model isn't perfect. I think the issue is with the elevator authority after loosing the rudder is to great and ailerons seem to provide more pitch authority than they should, thus saving what should be a doomed aircraft. Unless there is a % of probability calculation that needs to be tweaked.  

[JG7_X-Man]

On 1/21/2019 at 10:32 AM, unreasonable said:

 

What on earth is the matter with you?  I gave a source:  "a800109 "Effectiveness of incendiary ammunition against  aircraft fuel tanks" available online" it is right there in my post with the extract I provided. Google it and you get taken straight to the original. 

 

I did not say or imply that the German HEI - or any other shell - would always fail: I simply asserted that some 20mm cannon hits can indeed be sealed, and presented proof in the form of a quotation from people who know what they are talking about.  And then there are the tables which show that not all hits penetrate and not all penetrations cause fires. These are simple and indisputable facts. That is also true for mineshells: of any size.

 

It is good that you are done here. 

 

 

 

 

 

 

Very good points! However, no one is disputing your notion that a self sealing fuel tank would fail when hit by a single 20mm round of any sort. What we are disputing is any notion that suggests a self sealing fuel tank would not fail when hit by multiple rounds (which include incendiary, armor perring or tracer rounds). Any combination of multiple hits will cause the tank to either catch fire, explode or stream fuel which mixes with oil and heat and catches fire (we have all seen gun cam footage of such).

 

You can google self sealing tanks and in the footage you see, no one is firing more than 1-2 rounds (...not 1-2 second bursts)

https://www.youtube.com/watch?v=jwvlZISfMeg

 

The above is propaganda video to put parents and soon to be US airmen minds a little at ease, but notice how they didn't not use sustain rate of and that is obviously a .50 cal round.

 

This will give you a size gauge:

 

Note: (see the dime) for size reference

A1 are US .50 cal and UK .303 rounds respectfully.

B : 7.92mm MG 17 ('39 - '42)

C : 13mm MG 131('42+ ) 

E:  20mm MG FF (Bf 109Es)

D : 15mm MG 151/15 (Bf 109F-2)

F :  20mm MG 151/20

G : 30mm Mk. 108 (designed to destroy bombers and effective against light amour)

H : 30mm Mk 101/103 (the 101 same as the 108 with a large cartridge to takeout bombers from further (safer ~500ft) distances,  but the weight and low rate of fire made it useless for it's purpose but devastating when up close. The issue was solved with the much lighter Mk 103 with an electric firing mechanism that significantly increased the rate of fire, slated for the K-14 but luckily like everything else it came too late to make a difference.

Edited January 24, 2019 by JG7_X-Man

[unreasonable]

52 minutes ago, JG7_X-Man said:

 

Very good points! However, no one is disputing your notion that a self sealing fuel tank would fail when hit by a single 20mm round of any sort. What we are disputing is any notion that suggests a self sealing fuel tank would not fail when hit by multiple rounds (which include incendiary, armor perring or tracer rounds). Any combination of multiple hits will cause the tank to either catch fire, explode or stream fuel which mixes with oil and heat and catches fire (we have all seen gun cam footage of such).

 

 

 

 

This was not my notion (I think there is a "not" missing?). My notion was, that the notion that "nothing is sealing a 20mm hit", while intuitively plausible, is not in fact always true.

 

As to  "Any combination of multiple hits will cause the tank to either catch fire, explode or stream fuel which mixes with oil and heat and catches fire ....".   This is not strictly true either.  Not any combination of hits will do this: some - indeed many combinations of hits will do this, but not all fuel leaks will be ignited by subsequent hits.   This is shown in Figure 10 and Table 1 (second part) in the report a800109, which is the probability of fires being started from a subsequent perforating hit on an already leaking fuel cell.  You can see from this that not even incendiaries - or for that matter 30mm mineshells - had a 100% chance of starting a fire in these circumstances.

 

Clearly the more hits you get the greater the chances of leaks and fires - no-one would dispute that. 

 

On the game's DM my own view - based on the testing on the P-47 alone so far - is that fuel cells are punctured far too easily by splinter damage from hits some distance from the fuel cell itself. I do not have a firm opinion on their vulnerability to direct hits: but given the over-vulnerability of radial engines to direct hits it would not surprise me if the same was true for fuel cells.

 

edit: nice little film clip, BTW.

 

 

 

 

 

 

 

Edited January 24, 2019 by unreasonable