Cannon damage below 30mm is being done wrong

Machinery of War Discussion Aircraft
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The way cannon shells are doing damage is fundamentally wrong. They should not be ripping wings off. They should not be blowing tails off, or larger control surfaces. What they should be doing is cutting control cables, starting fuel and oil leaks, and killing your pilot.

High explosive shells

I want to start the conversation with this video for a very simple reason. The shells used in the test data have 58% more muzzle energy, and 3 times as much TNT as the shells in the video.

Let’s start with some terminology. An “A” kill is damage serious enough for the aircraft to be disabled within 5 minutes(Think fires, serious engine damage, pilot death). A “B” kill is damage that will cause the aircraft to crash between 5 minutes and two hours(Think fuel and oil leaks). The only thing that matters to Warthunder is “A” kills. This post relies heavily on data taken from the optimum caliber program and is by proxy, heavy with terminology derived from it.

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These firings were conducted against a P-47 at its most vulnerable angle, where the pilot is not protected by armor, and where most of the internal systems are. The chance for a singular 20MM HEI shell to kill a P-47 is 6.1%, with nearly half of that being the death of the pilot. Structure accounts for a measly 1.9% of the total chance for an “A” kill. The report defines structure as:
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To end this conversation on explosive damage, let’s look at some real-world examples. In fairness, these are examples of survivorship bias, but it’s important to look at them nonetheless.
Entry hole(MG-151 mineshell):

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Exit holes(MG-151 mineshell):
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A6M zero 20mm entry hole:
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Exit:
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Note that the control cables are completely undamaged, even though the cannon shell fuzed right on top of them.

For reference, one 30mm Mk 108 damage:

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So, are smaller-caliber cannons overperforming? Yes, absolutely. They are doing far too much damage to the structure of the aircraft. That Bearcat at the beginning should not have lost its wingtip. I highly doubt it would have even fully lost its aileron or wing control, given the fact that the Bearcat does not use cables, but push-pull rods. So, what should high explosive cannon shell damage be doing? It should mostly be killing pilots/ crew, causing excessive drag, and making control surfaces inoperable. So why change the way cannon damage works now? The severe damage mechanic effectively eliminates kill stealing, which is the main reason that cannon damage was so high to begin with.

I would like to thank @KillaKiwi for the Bearcat footage and @DerGrafVonZahl for giving me data from the optimum caliber program.

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I don’t see how this proves 20mm is over-performing.
1 20mm shot does about as much damage in-game as the picture to my knowledge.

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Did you watch the video at the beginning? Because a 20mm should not be doing that

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Which only proves that the damage model is allegedly under-performing, not that the round is over-performing.

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That’s just a different way of saying that cannons are overperforming. I used the Bearcat video as an example of what was one of the weakest 20mm cannons historically, vs an above-average airframe. Nevermind the fact that shots like this are pretty constant by most props with cannons against most other props

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No, because the damage FROM the round is correct.
The “health” of the structure is too simplistic and needs complicating.

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But it’s not correct. Shots like this with the shavak happen on the regular versus a variety of aircraft

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Yes this was implemeted somewhere in 2013. There was a lot of killstealing and complaints about planes losing tail controls even they were hit in the front (the cable got jammed or ripped). People couldn’t understand how a hit from the front damaged their tail.

Also people followed doomed planes until they hit the ground to get the kill since there was no visual damage on them and they weren’t burning.

Then there was a patch and the cables no longer were easily damaged, instead the tail just fell off. The kill was granted immidiately and we got less killstealing and stupid behaviour in exchange for Micheal Bay visuals.

But now we have “severe Damage”, the Micheal Bay visuals are unnecessary now. You might want to flag the labes of severely damaged planes so planes that look flightworthy aren’t shot unnecessarily. But now at least the original fighter that has gotten the kill gets the reward.

Wo do not need Micheal Bay explosions anymore.

The only thing to be wary about is that there exist no research data that shows how the structure of aircraft rreacts to cumulative damage, but the research indicates that the chances that the plane is dead log before a Wing or Tail would fall off is pretty high. With the exception of the 30mm Mineshell (the 20mm mineshell wasn’t tested) that indeed kills you by ripping you apart at least according to the research. But interestingly the american 37mm HE doesn’t.

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From what I understand, most of the 37mm HE’s power goes into lots of very heavy, very powerful fragments. So while it does not rip your aircraft in two on the regular, what it will do is completely destroy all the internals, and set everything on fire.

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The american 37mm HE also has considerably less explosives than the german 30mm.

so the irl answer to ripping planes apart was explosives… lots of them.

Yes the explosive structural damage is indeed at the cost of other damage. Easily visible due to the fact that even though the Structural damage is extreme to the M54, the overall probability of a kill is lower. And again this is “A”-Kills were structural damage has a higher impact.

This is also a lot due to philosophy, why the german guns were actually more about ripping the enemy apart.

  1. a dying bomber that can still limp to the target and drop bombs, remains a thread. A crippled fighter that can stil fly for 10 minutes is out of the fight. So the americans and especially the british weren’t that interested in big explosions. They only had to protect bombers, not stop them.

A good comparison is stopping power of rifles. a 5.56mm is as good at killing you as a 7.62mm however the 7.62 has way more stopping power. Since you won’t die immidiately from either, the 7.62 is much more likely to throw you on the ground on impact stopping you from fighting while a 5.56 wound will not immidiately stop you. Same with the german guns, they weren’t just interested in killing the plane they wanted to stop it releasing it’s bombs. While the US and the british were fine with just killing the planes.

The reason i said that the british were special in this case is that like their attitude with their HESH rounds for tanks they had their special aircraft rounds “SAP-Rounds” those are interesting and horribly modelled in wT due to the Micheal Bay effect.
So instead of explosives, they filled their 20mm with incindiary liquid. In game they are modelled as slightly weaker HE shells than their regular HE shells and not as a special round only the british used.
The other allies didn’t like them because even for them just spraying liquid and ingiting it into a plane with a 20mm was to slow for a kill. And yes it took it’s sweet time to kill, but it did kill planes very reliable, it actually was comparable to the german 20mm Mineshell in damage, it just took longer.
Again horribly modelled in WT and if someone asks himself how the hispanos of the brits feel weaker than of any other nation, it’s because of how SAP rounds are modelled in WT.

But thats not all, there was a second reason the germans used so much explosive filler:

  1. The eastern front. The russians early planes were built from wood, that if treated correctly was similarly sturdy to impacts and resistant to heat damage as aluminum is. But it really doesn’t like to be shattered, it didn’t react well to being shattered like an explosion would do. So russian planes when hit with HE should desintegrate far more frequently than other allied planes. And since the germans were more interested in dealing with the eastern front, this is the way they went. But it didn’t made the german shells better, just more spectacular.

So yeah at least for the western allied and the german planes wing rips etc. happen way to often.
Since for russian and wooden planes no research exists this might be harder to assess.

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Ultimately nothing is going to be perfect. But I’m sure getting rid of the Michel Bay wing and tail rips will make the game much better. especially for sim pilots and people who want to bring crippled planes back.

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The damage from the round is incorrect, in that the way its doing damage is physically impossible

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Well yes, but i would be careful.
We are only talking single hit damage as there is no data on cumulative damage and we usually hit the same spot with several rounds.

I doubt that the amount of hits needed for a kill are an issue in WT. Especially if younconsider B kills as well. Which you should.

So it will create.longer suffering until death but the survivability shouldn’t really change.

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We don’t hit the same spot several times though. For most 20mm cannons, the dispersion is usually large enough to cover 1/2 of the aircraft. Commonly when using the F4U-4B, I find myself blowing off both wings with a short burst. And frankly, having wings not get ripped off may not be the most important statistic in air RB, but it can be the difference between dying and limping back in simulator battles. And even if we do hit the same spot with several rounds, it should not rip the damm wing off.

As for kill hits, it’s a lot more important. Not so much for fighters but for attackers and bombers. Not having your wing ripped off, only damaged, can give you enough time to shoot back or survive until friendlies get to you.

Why would we consider B kills? If you look at the data, the two biggest factors in a B kill are engine and fuel, which does not matter in war thunder due to how close the airfields are.

That’s my reasoning for why these changes need to be made.

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@DerGrafVonZahl
Very nice summary - fully agree to your first post.

I do not understand why these kind of discussions (wt vs reality) are popping up from time to time. I mean besides this “severe damage” disaster (as it has imho just negative effects) the arguments / opinions are always the same.

Hidden as imho off topic - I am not sure if your 2nd post is on the right path

First of all the stopping power examples are imho misleading.

  • The 5.56 in rifles were based on post-war analysis of actual combat ranges, actual hit probabilities and ammo capacity/weight of ammo.
  • The idea was to bring as much bullets out of rifles in the short time the enemy is visible / in sight - so lower calibers increase fire rate and aim due to less recoil - and the soldier could carry way more ammo.
  • The long range accuracy of higher caliber full power ammo was seen as unnecessary for the standard /average soldier.
  • The Mauser 7,92 x 33 in the StuG 44 was dealing with stopping power, accuracy and “controllability” due to way less recoil than the 7,92 x 57 in actual combat ranges very successfully.

And i struggle to follow other claims like:

  • Your argument that the LW tried to intercept bombers before drop and therefore needed explosions is imho not backed by any source.

  • The fact that all nations used cannons is imho just based on the fact that the usually short time of a firing solution should be used with maximum effect. As even 20mm HE struggled to kill bombers quick we saw the up-gunning with calibers up to 50mm.

  • The US had very interesting bomber interceptor concepts long before WW2 (you might remember this aircraft from 1937) and were fully aware of the need for cannons. But they relied on the 37mm M4 (as seen in P-39) and struggled to make the AN/M2 working as wing mounted guns. The wide usage of 0.50 cals in P-51s/P-47s has therefore nothing to do with “just protecting the bombers, not to kill them”.

  • The wing mounting of batteries of 6 or 8 0.50 cals with large ammo pools had significant advantages for the standard/average pilot as it created a deadzone (area converging, nor point converging) 3-600 yards in front of the aircraft - and required way less marksmanship than a single center mounted cannon.

  • The Hispano 404 and its versions are usually recognized as one of the best 20mm cannons - and Spitfires used them even in 1940 in the BoB as they realized that rifle bullets were not effective enough. So i cant follow the logic of this quote too:

  • In any case - have a good one!

Sorry man, this is a common misconception. Just read this thread and learn why:

https://forum.warthunder.com/t/severe-damage-did-nothing-to-fix-kill-stealing/84776

From a holistic perspective the new mechanic even increases the possibility for kill stealing (especially for non-fighter targets) as instant kills were reduced to pilot snipes and cutting the tail off.

I share most of the views of this fellow player:

Last, but not least:

I struggle to understand your obsession with A and B kills. You play a video game with little to zero connection to actual reality…

Edit: Added 2 lines to make clear that this post was addressed to 2 people

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I mentioned A and B kills so people understand what the graphs mean. Also love the fact that you respond not to the post itself, but to me replying to someone else.

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Producing one post instead of 2 is a problem? Jeez…

Dude - i responded to the first post of @DerGrafVonZahl as this was a very nice summary of why we have certain effects in wt.

And in this response i added a quote of you to clarify your misinterpretation of the severe damage model and i added that i was wondering why you try to connect irl stuff and wt - emphasising A/B kills implies irl thinking which wt is either unwilling or unable to provide.

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emphasising A/B kills implies irl thinking which wt is either unwilling or unable to provide.

I know perfectly well that warthunder is about as unrealistic as can be. What I was trying to do is show that 20mm cannons are massively overperforming in terms of structural damage, and that the way they do damage is fundamentally wrong. The optimum caliber program is probably the most scientific way of determining damage we have access to, especially for WW2 era guns.

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I would disagree here.

The A/B kill distinction is relevant if you want to assess how close the WT Damage modelling is to real life.

Of course it isn’t applicable to AB and RB where the instructor can hold an aircraft in the air, where a real pilot would fail. Similar to how a fly by wire system can keep very unstable planes stable.

But for the Sim Community it would matter.

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And I would argue that it would still be a net boon to air RB, as weapons like the Mk 108 would go from being memes to actually having a risk-reward tradeoff, instead of being completely overshadowed by 20mm cannons

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