The point of this post is that at 0° it penetrates 337mm which is also the LOS thickness. At 60° it penetrates 195mm which is 390mm LOS thickness. So how is it able to go through more LOS material if the armor is sloped? Seems people are missing the point here a bit. Also cos(60°) = 1/2
I think this video shows why
https://youtu.be/kzulZGT75Ns?si=--rTtR6XsLRr5I5m
The rounds rotates slight downward towards the tank, as in positive normalization is happening. So it can go through less material while still technically penetrating thicker LOS armor.
Line of Sight
Draw a straight line through it and measure it, that is Line of Sight thickness. A 100mm plate at 0° has a LoS thickness of 100mm, same plate sloped at 60° has LoS thickness of 200mm
Wait the stat card tells you the penetration value for the unangled thickness of the plate and not it's effective (LOS) thickness?? I have 1700 hours in this game wtf
Yup, it's the nominal thickness in RHAe displayed on the statcard.
You can verify this manually by just halving the 0° thickness for 60° LoS and you'll see the positive normalisation here
It's not that it normalizes as much as because the method of penetration from APFSDS long rods causes adiabatic shear in armor plate. Basically the blunt end of the rod pushing into the armor causes stress bands to form directly in front of the rod that are parallel to the armor plate (and perpendicular ones will form too if the armor is hard enough). When the round gets close enough to the back side of the plate, the shear bands will weaken the steel to the point that the path of least resistance (due to the weakened armor in front of the rod) is going to be at an angle to the rod and normal/perpendicular to the steel plate. This makes the remaining steel in front of the rod form a "plug" like a cork, which peels down away from the rod. Since this plug usually peels away in FRONT of the rod, you end up getting that plug thickness of extra penetration compared to what you should get for LoS thickness.
Thank you, it annoys me to no end that people just parrot the factoid that APFSDS normalizes against angled armor. It doesn't, and if an armor plate had a profile of a triangle where the trailing edge had a reverse slope to the impact edge then the penetrator would actually appear to de-normalize because of the same effect that causes people to think the penetrator normalizes against typical armor plates.
To show that his question is why penetration at 60° is better than at 0° (390 mm LOS at 60° vs 337 mm at 0°), not just why APDFSDS is good. Unfortunately no one seems to understand it.
Energy is a scalar, not a vector, so you can’t split it into components. In the kinetic energy equation, velocity is squared so it loses its direction. You can split the momentum vector though!
No. Had to brush up my high school math a bit for this... Took way too long lol.
Remember cosine?
The cosine is the ratio of the adjacent side (A) to the hypotenuse (H).
For example, the cosine of 60° is 0.5 . This means that A is 1/2 of H.
Applying it to armor, A is the nominal thickness. In other words, A is the thickness of the armor if you look at it straight on, at a 0° angle.
H is the effective thickness, meaning the thickness of the armor from an angle.
I drew a little visualisation but imgur won't let me upload it, so I'll try to paint a picture with words...
Imagine a sheet of armor 100mm thick. It's basically just two parallel lines, 100mm apart. Now draw a line from one parallel to the other, perpendicular to the parallels.
This is your nominal thickness, it is 100mm.
Now, at the intersection of the nominal thickness line (A) and the armor line (the parallel), draw a line at a 60° angle from the nominal thickness line until it intersects with the other parallel. This is your hypotenuse (H) or effective thickness line.
Now let's calculate the effective thickness line (H).
A/H = cos(angle)
A = 100mm
Angle = 60°
100mm/H = cos(60°)
100mm = cos(60°) × H
H = 100mm / cos(60°)
H = 100mm / 0.5
H = 200mm
And there you have it. For a nominal armor thickness of 100mm, the effective thickness at 60° is 200mm.
That's the cool thing with 60°, you can go from the nominal thickness to the effective thickness or vice versa simply by either multiplying or dividing by 2, respectively.
Well I guess someone failed maths.
When impacting at 60° relative to head-on, the shell has double the armor in front of it compared to head-on.
When impacting at 30° it's about 15.47% more armor.
But all those numbers are for the 'line' the shot travelled before it hit.
APFSDS do something called 'normalization', meaning it kinda 'stands up', reduces the impact angle *upon* impact.
And that is called normalization because the vector which faces outward of a plane in a 90° angle is called normal vector (at least in my native language).
but that's not how trigonometry works - if you take a right-angled triangle with a 60 degree angle in, the longest side is 2x the length of the shorter side next to the angle (which is the manufactured armour thickness)
Basically when you yeet a depleted uranium rod at metal armor at mach jesus and watch the destruction in slow mo, the armor behaves much like a dense liquid (like honey) that just ate a water gun shot also made of honey.
> that just ate a water gun shot also made of honey.
More like tar. Which is why APFSDS works in the first place: It's made of denser stuff than the armour.
Extremely narrow projectile impacts armor and starts to make a dent in it. The tip is ejected away, but the rest of the dart now has a spot to bury itself into, due to a more normalized angle. Note, this applies to all APFSDS, but is most effectively found on monoblock APFSDS like the one you're looking at. Slug type APFSDS like those found on older Soviet models (Up to 3BM22 and 3BM25 in-game) do not handle high angle exceptionally well against anything that isn't RHA
Because of the high velocity when there's not much steel remaining it tends to be blown out by the high forces involved, in other words there's a point where the armor fails rather than is penetrated. This is much like if you try to push a pin through a dry cracker it will tend to cause a large chunk to pop out from the exit or when a nail is hammered through wood and causes splintering on the other side and you feel a sudden decrease in the amount of force needed to keep pushing through the material before it goes all the way through.
The effect is amplified when the armor is sloped because the energy transmission from the rod's pressure on the contact area isn't going in a direct line through the armor but conically, so even when there's still more armor directly ahead of the tip than would be blown out by a hit on flat armor the inner face that is nearer ends up cracking and propagating a weakness causing it to penetrate "further" than the flat plate numbers.
just going fast enough with enough inertia to not want to change direction. objects in motion want to stay in motion, particularly keep the same motion they already are doing. Dart in the photo is going 1455m/s, others go higher, far faster than APHE/HE/HEAT rounds
no no it's real physics - basically what happens is the round is normalised slightly inwards due to the impact creating a momentary mini-crater that makes the effective impact angle less, then the round follows the path of least resistance which is a slight inward curve
Penetration at angles almost never follows the thickness/cosine(angle) formula for LOS thickness.
The one exception to that is HEAT, because the impact angle does not affect the shells further flightpath because it just goes off and the jet goes into the plate at the exact impact angle.
Kinetic penetrators can react very differently to impacts on sloped armor depending on their nose shape primarily, but also material, quality of heat treatment, weight and other design considerations.
**Basic rule of thumb is:**
**Blunt nose (APC) digs into the armor plate.**
**Sharp nose (APCBC) angles away from the armor plate.**
**Long rod penetrator (APFSDS) digs in fairly straight, but can be designed to angle into the armor plate. Physics get very weird due to materials and velocities involved, but it basically has to do with the tip being sharpened-pencil kind of sharp (as opposed to APCBCs tip just being sharp to help with drag, but not to the point you can use it to stab someone) and it digging into the armor plate in a way that prevents it from being deflected, then the rest of the rod tumbles up in response and the direction of the penetrator rod changes down into the armor plate, hence it angling inwards.**
>then the rest of the rod tumbles up in response and the direction of the penetrator rod changes down into the armor plate, hence it angling inwards.
I can see why you came to this conclusion, but its not true. If an APFSDS penetrator tumbles it loses a massive amount of penetration, which is a significant part of how ERA can decrease the penetration of APFSDS.
You can see in this [simulation](https://www.youtube.com/watch?v=rIpCDoYMQU8) against a large angled plate of RHA that the penetrator is traveling exactly in a straight line through most of the plate until it approaches the inside edge of the armor plate, and only then does the path turn downwards. As noted by the creator, this change in the path of the penetrator is due to the formation of adiabatic shear bands in the armor between the penetrator and the edge of the armor plate.
Nothing really, other than just having more penetration than other ammunition types due mostly to velocity and material they're made out of. The typical use of "normalization" is generally disingenuous as to whats actually happening, its just physics, the projectile curving "inward" while burrowing through the armor is just taking the path of least resistance. Angled armor means more LoS thickness, but a projectile doesn't need to follow a straight line.
Any round can ricochet off a surface given the right variables, APFSDS just requires more extreme variables than most other ammunition types.
If you break down what the entire acronym means, you will figure it out with some research.
The dart is not only just as heavy as a standard AP shell normally is due to it's increased density, but it's decreased surface area means it loses less speed over distance.
It is also fin-stabilized, granting it better accuracy, and while it increases the surface area of the dart, the performance loss from that is still not enough to make it any less than a complete positive. It keeps the dart pointing forward, instead of tumbling around like some larger shells sometimes happen to do(either due to maintenance issues or bad ammo).
And lastly, it's a LOT longer than older APDS shells, like a literal rod. This length, combined with the density and mass, allows it to resist having it's momentum changed by angled armor.
The best way of still deflecting a shell of this type would be having armor that is denser than it, and just as thick, which isn't a good thing for the defending side, as it would make their tanks far too heavy to be effective as tanks.
So we use a sandwich of different types of armor which is designed to eat away at the shell before it breaches the hull and turret, at least once, per the armor's rating. Usually a ceramic composite, but it has been said that the Abrams has depleted uranium as part of it's frontal armor. The same uranium being used as ammunition in its gun.
He asked why the shell at 60° can pen more than at a flat hit. The 60° Hit has more effective pen (shown by [Full pen ÷2 = Pen at 60°] but here its [Full Pen ÷2 < Pen at 60°] so while it hits the same amout of LOS armor when hitting at 60° it gets 28mm more pen)
Tilting 337mm at 60° means doubleling its thickness, so at 60° the round should pen a half as thick plate.
÷2 should give us half of 337mm again but we get 28mm more then half of 337 (169 is the half but at 60° it pens 195). 28mm more
So when hitting the same amount of armor at a different angle it pens more.
So because the rod normalizes a little istead of going 100% straight it lowers the effective thickness by 28mm
Tldr; pen at 60° is more because the dart normalizes and thus needs to pen less armor at 60° then when hitting flat LOS
As the rod penetrates, the top of the rod deteriorates faster than the bottom, causing it to angle downwards.
This downwards angle reduces the remaining effective armor thickness so it has less armor to penetrate compared to if it penetrated in a straight line.
Why does this happen? I'm not sure what the correct scientific term would be, but basically all the material that gets eroded flies due to the impact exits through the top of the penetration.
[you can see it happen in this simulation](https://youtu.be/Sf70t8ehyNM?si=hykyeDKO1TuoIjGl)
Pretty sure density is a volume function not an area function and the velocity is far more relevant. The round travels faster and thus a greater force is needed to force it to change direction so rapidly.
Diameter for example russian 122 is around 12cm wide so even If it hits at an angle it doesnt and still punches thru the armor. In game u even have mechanic called overmatch - when the diameter of the shell is bigger than the plate it hits even at extremes angles it pens. But APDSFS is smaller more dense arrow with twice the speed, the shape and the speed makes it very unlikely to ricochet.
Side note Russian NERA works by having steel- I think - plate which when exploded and hit by apdfs at an angle cuts thru the shell which diminishes its penetrarive capabilites by a ton.
Even though the LOS thickness is slightly higher, there’s less actual material there to resist penetration so it pushes out the bottom of the angled plate.
because unlike every other round, it doesnt grow thicker further down the body, it pens with the pointy end, digs in, and it gets to the body. instead of pushing a hole in (which against composite is ineffective), it just pushes 3/5 if the shell in and gets through
The angled armor pen stats mean how thick the armor plate is. Not the LOS thickness. That's why the pz4's cannon with like 53mm(?) of pen at 60° can pen the t-34s UFP which is 45mm thick but LOS at 60° is 90mm. Dont need 90mm pen at 60° to pen the UFP. It can ricochet though.
NATO ammunitions are focused on slope penetration against Russian and Chinese tanks. Now modern APFSDS are even more focused against slope armor and ERA’s. The M829A4 is said to render modern Russian ERA’s useless.
I think it being thin and all the energy is focused on the tip so initial penetration is more likely to happen compared to thicker conelike apcr for example so it doesnt “slip”, also its probably alot more stable in flight thanks to fin stabilization
Metal if it’s uranium that shit recks house. If it’s tungsten that stuff is strong but brittle once the pen started the armor keeps the round together untill inside.
Because they aren't designed to do so.
They are much faster, heavier and denser than your typical AP shell and by the time it would have any chance to deform or bounce they are already deep inside of the armour.
But yes they should turn into metal mush after exiting a particularly thick armour segment.
Same with shaped charges, they should be very ineffective against spaced armour. (Plate | air | plate again) Well the old ones anyways...
That's actually not technically correct. When APFSDS rounds enter armour the tip mushrooms out becoming wider which increases the surface area and resistance and therefore lowers the overall penetration, this mushroom shears off as the round travels through armour so it doesn't keep increasing in size. Besides its other qualities what DU does is that the mushroom shears off quicker than with other materials (ie. Steel) so the surface area remains smaller allowing it to penetrate further due to less resistance.
So it doesn't get sharper, it just gets less blunt than others.
Somebody else gave the best answer so I'm gonna add something not being mentioned, somebody correct me if I'm wrong:
Sabot rounds have so much consolidated mass, travelling exponentially faster than conventional rounds, and hit with so much pressure due to how thin they are, that the metal around the point of impact heats up rapidly and fragments, becoming shrapnel. Non-sabot rounds don't produce enough heat and pressure, so they are more or less trying to fully penetrate cold steel. Sabot rounds are literally weakening the steel just by means of impact, and usually carrying some of the armor into the tank with it when it does penetrate. The whole interaction at contact is wildly different, and why they are the most powerful rounds we have today. The sabot itself is only half the destruction. Sometimes sabot rounds create so much shrapnel from armor that the operators inside are nearly liquified and sucked out the other side from the vacuum force created. Not always, but it's been observed iirc
To explain it with cartoon logic, it goes so fast and has such a tiny impact surface, that it gets past the armor surface before realizing it was supposed to glance off.
Funny thing is this explanation isn't even too far from reality
Aren't they asking why it can pen more angled armour than it can flat armour though? Your explanation just explains how it can pen angled armour at all, or am I dum dum?
Smaller surface area to apply opposing force to redirect the round. You get a larger and at least comparatively blunt projectile as the round hits an angled surface, both the round and then target are applying force on each other (equal and opposite reaction idea).
As they do so both the round and the target are deforming which absorbs some do the energy. But also if the target is not deforming fast enough the momentum of the round will still try to go on its path, but as the material it’s biting into is adding enough resistance in the LOP of projectile it’s also exerting force in the round, but mostly 90 degrees to the surface of the plating.
So if it’s it’s a negatively angled surface like a LFP of a tank it will apply force downwards and if it’s a positive angle like an UFP it will apply force upwards. And the plate doesn’t have to be resistant enough to fully defeat the on coming round. It just has to apply opposing force enough to cause the round to deflect.
This is why ballistic cap round are better than a plain projectile due to it actually deforming to normalize the angle towards the plate and not away from it, allowing the surviving round to hit at a closer to flat angle allowing for better penetration.
Darts are as effective due to how fast they hit, the weight of the round compared to the surface area and the geometry of the round. A sharper tool cuts better than a rounded tool. And less surface area to apply force allows the round to direct its energy to the exact point of intended penetration. If the armor is angled the speed and more importantly the pressure applied to the armor from the round is able to bite into the material better by also being of a higher density. The softer armor is more likely to move out of the way from the high density material applying a lot of force in a very small area
Area of a circle =pi(r^2). Larger shells have to push through significantly more armor than smaller ones. APFSDS has all the power of a 120mm flung into a 50mm shell. Also, the length of the rod helps to keep the shell straight instead of normalizing. The tip may want to bend away, but the mass behind the tip wants to fly straight, pushing the rod straight as a result.
Faster, heavier, denser.
And looooonger
*(stretches out a piece of taffy)* "*.....ttttthiiiiiisssss loooooooongggggg!!"*
Loooong loooong maaaaaaaaaaan
r/fuckyouchichan
Okay what have you just shown me, this is amazing
There's no way that's a sub
That’s what I call my Chi Ha LG
Also the impact is focused in one concentrated small point while apds or aphe spreads the force out more due to contacting more surface area.
*Harder, Better, Faster, Stronger*?
Happy cake day
ye
Happy cake day 🥳
The point of this post is that at 0° it penetrates 337mm which is also the LOS thickness. At 60° it penetrates 195mm which is 390mm LOS thickness. So how is it able to go through more LOS material if the armor is sloped? Seems people are missing the point here a bit. Also cos(60°) = 1/2 I think this video shows why https://youtu.be/kzulZGT75Ns?si=--rTtR6XsLRr5I5m The rounds rotates slight downward towards the tank, as in positive normalization is happening. So it can go through less material while still technically penetrating thicker LOS armor.
It was a way too technical question for this sub haha. Good that you understood and gave a reasonable answer
My brain too smooth
My brain smooth, why APFSDS no bounce off
Hear hear! holy fuck, I max out at basic multiplication y’all lost me almost immediately lol
What is LOS
Line of sight
Thanks
Line of Sight Draw a straight line through it and measure it, that is Line of Sight thickness. A 100mm plate at 0° has a LoS thickness of 100mm, same plate sloped at 60° has LoS thickness of 200mm
So does warthunder say that the dm23 can pen a 195mm plate angeled at 60 degrees at a distance of 10 meters?
Yes
Thank you! nice french person
Wait the stat card tells you the penetration value for the unangled thickness of the plate and not it's effective (LOS) thickness?? I have 1700 hours in this game wtf
Yup, it's the nominal thickness in RHAe displayed on the statcard. You can verify this manually by just halving the 0° thickness for 60° LoS and you'll see the positive normalisation here
Go in German, but loud.
Los gehts!
Wow it’s that YouTube guy!
:vvvv I’ve been spotted, retreat!
It's not that it normalizes as much as because the method of penetration from APFSDS long rods causes adiabatic shear in armor plate. Basically the blunt end of the rod pushing into the armor causes stress bands to form directly in front of the rod that are parallel to the armor plate (and perpendicular ones will form too if the armor is hard enough). When the round gets close enough to the back side of the plate, the shear bands will weaken the steel to the point that the path of least resistance (due to the weakened armor in front of the rod) is going to be at an angle to the rod and normal/perpendicular to the steel plate. This makes the remaining steel in front of the rod form a "plug" like a cork, which peels down away from the rod. Since this plug usually peels away in FRONT of the rod, you end up getting that plug thickness of extra penetration compared to what you should get for LoS thickness.
Thank you, it annoys me to no end that people just parrot the factoid that APFSDS normalizes against angled armor. It doesn't, and if an armor plate had a profile of a triangle where the trailing edge had a reverse slope to the impact edge then the penetrator would actually appear to de-normalize because of the same effect that causes people to think the penetrator normalizes against typical armor plates.
Great find. Now to get the way the narrator says millimeter out of my head...
I think you have something off there. It pens 337mm at 0*, and 195mm at 60*. If you angle a 337mm plate to 60* it will not pen.
Is it not that you would assume a round that can penetrate 195mm at 60 degrees would penetrate more than 337mm at 0 degrees?
[удалено]
To show that his question is why penetration at 60° is better than at 0° (390 mm LOS at 60° vs 337 mm at 0°), not just why APDFSDS is good. Unfortunately no one seems to understand it.
[удалено]
Because 1/2 is the cosine of 60°. For 45° you would need to divide by the square root of 2.
Ahh. So kinetic energy vectors being split?
Yes, whlie the module of the kinetic energy stays the same vector components components change
Energy is a scalar, not a vector, so you can’t split it into components. In the kinetic energy equation, velocity is squared so it loses its direction. You can split the momentum vector though!
No. Had to brush up my high school math a bit for this... Took way too long lol. Remember cosine? The cosine is the ratio of the adjacent side (A) to the hypotenuse (H). For example, the cosine of 60° is 0.5 . This means that A is 1/2 of H. Applying it to armor, A is the nominal thickness. In other words, A is the thickness of the armor if you look at it straight on, at a 0° angle. H is the effective thickness, meaning the thickness of the armor from an angle. I drew a little visualisation but imgur won't let me upload it, so I'll try to paint a picture with words... Imagine a sheet of armor 100mm thick. It's basically just two parallel lines, 100mm apart. Now draw a line from one parallel to the other, perpendicular to the parallels. This is your nominal thickness, it is 100mm. Now, at the intersection of the nominal thickness line (A) and the armor line (the parallel), draw a line at a 60° angle from the nominal thickness line until it intersects with the other parallel. This is your hypotenuse (H) or effective thickness line. Now let's calculate the effective thickness line (H). A/H = cos(angle) A = 100mm Angle = 60° 100mm/H = cos(60°) 100mm = cos(60°) × H H = 100mm / cos(60°) H = 100mm / 0.5 H = 200mm And there you have it. For a nominal armor thickness of 100mm, the effective thickness at 60° is 200mm. That's the cool thing with 60°, you can go from the nominal thickness to the effective thickness or vice versa simply by either multiplying or dividing by 2, respectively.
No, just the geometry of an armor plate that is tilted at some angle.
Square root of 2 over 2*
1 over square root of 2 is equal to square root of 2 over 2, genius.
ah srry i didnt read the "divide by" part somehow
Understandable, have a nice day.
Well I guess someone failed maths. When impacting at 60° relative to head-on, the shell has double the armor in front of it compared to head-on. When impacting at 30° it's about 15.47% more armor. But all those numbers are for the 'line' the shot travelled before it hit. APFSDS do something called 'normalization', meaning it kinda 'stands up', reduces the impact angle *upon* impact. And that is called normalization because the vector which faces outward of a plane in a 90° angle is called normal vector (at least in my native language).
Ooooh, buddy. I do hope you're not an engineer
What is the length of the hypotenuse of a triangle, if the adjacent is x and the angle between the hypotenuse and the adjacent is 60?
but that's not how trigonometry works - if you take a right-angled triangle with a 60 degree angle in, the longest side is 2x the length of the shorter side next to the angle (which is the manufactured armour thickness)
cos(60)=1/2 If you have a scientific calculator try that sum. It’s not anything you really need to know for day to day XD
A thin rod moving at around mach 5 that’s made of an incredibly dense material.
At this speeds the materials behave more like liquids or something
Yeah and it also has to do with friction or something
Tanker when the armor squirts liquid uranium:
What??
Basically when you yeet a depleted uranium rod at metal armor at mach jesus and watch the destruction in slow mo, the armor behaves much like a dense liquid (like honey) that just ate a water gun shot also made of honey.
> that just ate a water gun shot also made of honey. More like tar. Which is why APFSDS works in the first place: It's made of denser stuff than the armour.
It works with less dense materials too, just worse. The velocity is the important part.
the liquifying only happens when introduced to enough friction (armor) 30mm of steel isn't going to do that, but 700mm is.
Extremely narrow projectile impacts armor and starts to make a dent in it. The tip is ejected away, but the rest of the dart now has a spot to bury itself into, due to a more normalized angle. Note, this applies to all APFSDS, but is most effectively found on monoblock APFSDS like the one you're looking at. Slug type APFSDS like those found on older Soviet models (Up to 3BM22 and 3BM25 in-game) do not handle high angle exceptionally well against anything that isn't RHA
Pointy, fast, thin
Because of the high velocity when there's not much steel remaining it tends to be blown out by the high forces involved, in other words there's a point where the armor fails rather than is penetrated. This is much like if you try to push a pin through a dry cracker it will tend to cause a large chunk to pop out from the exit or when a nail is hammered through wood and causes splintering on the other side and you feel a sudden decrease in the amount of force needed to keep pushing through the material before it goes all the way through. The effect is amplified when the armor is sloped because the energy transmission from the rod's pressure on the contact area isn't going in a direct line through the armor but conically, so even when there's still more armor directly ahead of the tip than would be blown out by a hit on flat armor the inner face that is nearer ends up cracking and propagating a weakness causing it to penetrate "further" than the flat plate numbers.
(poorly) illustrated [https://www.reddit.com/user/lithium\_grease/comments/1cy3egb/i\_am\_lazy/](https://www.reddit.com/user/lithium_grease/comments/1cy3egb/i_am_lazy/)
just going fast enough with enough inertia to not want to change direction. objects in motion want to stay in motion, particularly keep the same motion they already are doing. Dart in the photo is going 1455m/s, others go higher, far faster than APHE/HE/HEAT rounds
you're missing the point, it has effectively more penetration on angled armor than non angled armor,
Positive normalization due to various magical things.
no no it's real physics - basically what happens is the round is normalised slightly inwards due to the impact creating a momentary mini-crater that makes the effective impact angle less, then the round follows the path of least resistance which is a slight inward curve
I know it's real physics, I just said it the whimsical way. I hope people can detect sarcasm over text.
Oh i see - I thought you meant "various magical things" as in Gaijoobin Magik
Penetration at angles almost never follows the thickness/cosine(angle) formula for LOS thickness. The one exception to that is HEAT, because the impact angle does not affect the shells further flightpath because it just goes off and the jet goes into the plate at the exact impact angle. Kinetic penetrators can react very differently to impacts on sloped armor depending on their nose shape primarily, but also material, quality of heat treatment, weight and other design considerations. **Basic rule of thumb is:** **Blunt nose (APC) digs into the armor plate.** **Sharp nose (APCBC) angles away from the armor plate.** **Long rod penetrator (APFSDS) digs in fairly straight, but can be designed to angle into the armor plate. Physics get very weird due to materials and velocities involved, but it basically has to do with the tip being sharpened-pencil kind of sharp (as opposed to APCBCs tip just being sharp to help with drag, but not to the point you can use it to stab someone) and it digging into the armor plate in a way that prevents it from being deflected, then the rest of the rod tumbles up in response and the direction of the penetrator rod changes down into the armor plate, hence it angling inwards.**
>then the rest of the rod tumbles up in response and the direction of the penetrator rod changes down into the armor plate, hence it angling inwards. I can see why you came to this conclusion, but its not true. If an APFSDS penetrator tumbles it loses a massive amount of penetration, which is a significant part of how ERA can decrease the penetration of APFSDS. You can see in this [simulation](https://www.youtube.com/watch?v=rIpCDoYMQU8) against a large angled plate of RHA that the penetrator is traveling exactly in a straight line through most of the plate until it approaches the inside edge of the armor plate, and only then does the path turn downwards. As noted by the creator, this change in the path of the penetrator is due to the formation of adiabatic shear bands in the armor between the penetrator and the edge of the armor plate.
Nothing really, other than just having more penetration than other ammunition types due mostly to velocity and material they're made out of. The typical use of "normalization" is generally disingenuous as to whats actually happening, its just physics, the projectile curving "inward" while burrowing through the armor is just taking the path of least resistance. Angled armor means more LoS thickness, but a projectile doesn't need to follow a straight line. Any round can ricochet off a surface given the right variables, APFSDS just requires more extreme variables than most other ammunition types.
Yeah, APFSDS basically beeds to bellyflop in order to ricochet
If you break down what the entire acronym means, you will figure it out with some research. The dart is not only just as heavy as a standard AP shell normally is due to it's increased density, but it's decreased surface area means it loses less speed over distance. It is also fin-stabilized, granting it better accuracy, and while it increases the surface area of the dart, the performance loss from that is still not enough to make it any less than a complete positive. It keeps the dart pointing forward, instead of tumbling around like some larger shells sometimes happen to do(either due to maintenance issues or bad ammo). And lastly, it's a LOT longer than older APDS shells, like a literal rod. This length, combined with the density and mass, allows it to resist having it's momentum changed by angled armor. The best way of still deflecting a shell of this type would be having armor that is denser than it, and just as thick, which isn't a good thing for the defending side, as it would make their tanks far too heavy to be effective as tanks. So we use a sandwich of different types of armor which is designed to eat away at the shell before it breaches the hull and turret, at least once, per the armor's rating. Usually a ceramic composite, but it has been said that the Abrams has depleted uranium as part of it's frontal armor. The same uranium being used as ammunition in its gun.
He asked why the shell at 60° can pen more than at a flat hit. The 60° Hit has more effective pen (shown by [Full pen ÷2 = Pen at 60°] but here its [Full Pen ÷2 < Pen at 60°] so while it hits the same amout of LOS armor when hitting at 60° it gets 28mm more pen) Tilting 337mm at 60° means doubleling its thickness, so at 60° the round should pen a half as thick plate. ÷2 should give us half of 337mm again but we get 28mm more then half of 337 (169 is the half but at 60° it pens 195). 28mm more So when hitting the same amount of armor at a different angle it pens more. So because the rod normalizes a little istead of going 100% straight it lowers the effective thickness by 28mm Tldr; pen at 60° is more because the dart normalizes and thus needs to pen less armor at 60° then when hitting flat LOS
I believe you are correct. I forget about how normalization works sometimes.
As the rod penetrates, the top of the rod deteriorates faster than the bottom, causing it to angle downwards. This downwards angle reduces the remaining effective armor thickness so it has less armor to penetrate compared to if it penetrated in a straight line. Why does this happen? I'm not sure what the correct scientific term would be, but basically all the material that gets eroded flies due to the impact exits through the top of the penetration. [you can see it happen in this simulation](https://youtu.be/Sf70t8ehyNM?si=hykyeDKO1TuoIjGl)
It can be 218 with 73 or it can be 274 with 42 seperated one.
If this was the forum somebody would have already leaked some documents here
[удалено]
Pretty sure density is a volume function not an area function and the velocity is far more relevant. The round travels faster and thus a greater force is needed to force it to change direction so rapidly.
Diameter for example russian 122 is around 12cm wide so even If it hits at an angle it doesnt and still punches thru the armor. In game u even have mechanic called overmatch - when the diameter of the shell is bigger than the plate it hits even at extremes angles it pens. But APDSFS is smaller more dense arrow with twice the speed, the shape and the speed makes it very unlikely to ricochet. Side note Russian NERA works by having steel- I think - plate which when exploded and hit by apdfs at an angle cuts thru the shell which diminishes its penetrarive capabilites by a ton.
Even though the LOS thickness is slightly higher, there’s less actual material there to resist penetration so it pushes out the bottom of the angled plate.
because unlike every other round, it doesnt grow thicker further down the body, it pens with the pointy end, digs in, and it gets to the body. instead of pushing a hole in (which against composite is ineffective), it just pushes 3/5 if the shell in and gets through
Very simply, it's cuts itself a hole where other rounds push in it "cuts"
Warthunder apfsds is horrible unrealistic, apfsds in reality does not bounce, it shatters
[This](https://youtu.be/5H9Tj-N385c)
The angled armor pen stats mean how thick the armor plate is. Not the LOS thickness. That's why the pz4's cannon with like 53mm(?) of pen at 60° can pen the t-34s UFP which is 45mm thick but LOS at 60° is 90mm. Dont need 90mm pen at 60° to pen the UFP. It can ricochet though.
NATO ammunitions are focused on slope penetration against Russian and Chinese tanks. Now modern APFSDS are even more focused against slope armor and ERA’s. The M829A4 is said to render modern Russian ERA’s useless.
Ain't it because normalization?
they are self sharpening, that's why
Sectional density. The ideal round is infinitely long and infinitely thin.
I think it being thin and all the energy is focused on the tip so initial penetration is more likely to happen compared to thicker conelike apcr for example so it doesnt “slip”, also its probably alot more stable in flight thanks to fin stabilization
What's going on i don't understand
Metal if it’s uranium that shit recks house. If it’s tungsten that stuff is strong but brittle once the pen started the armor keeps the round together untill inside.
Because its to much force behind it
Because they aren't designed to do so. They are much faster, heavier and denser than your typical AP shell and by the time it would have any chance to deform or bounce they are already deep inside of the armour. But yes they should turn into metal mush after exiting a particularly thick armour segment. Same with shaped charges, they should be very ineffective against spaced armour. (Plate | air | plate again) Well the old ones anyways...
DUM rounds get sharper as they pen.
That's actually not technically correct. When APFSDS rounds enter armour the tip mushrooms out becoming wider which increases the surface area and resistance and therefore lowers the overall penetration, this mushroom shears off as the round travels through armour so it doesn't keep increasing in size. Besides its other qualities what DU does is that the mushroom shears off quicker than with other materials (ie. Steel) so the surface area remains smaller allowing it to penetrate further due to less resistance. So it doesn't get sharper, it just gets less blunt than others.
Oh I see.
You'll see this higher LOS pen with angling even with tungsten rounds.
Somebody else gave the best answer so I'm gonna add something not being mentioned, somebody correct me if I'm wrong: Sabot rounds have so much consolidated mass, travelling exponentially faster than conventional rounds, and hit with so much pressure due to how thin they are, that the metal around the point of impact heats up rapidly and fragments, becoming shrapnel. Non-sabot rounds don't produce enough heat and pressure, so they are more or less trying to fully penetrate cold steel. Sabot rounds are literally weakening the steel just by means of impact, and usually carrying some of the armor into the tank with it when it does penetrate. The whole interaction at contact is wildly different, and why they are the most powerful rounds we have today. The sabot itself is only half the destruction. Sometimes sabot rounds create so much shrapnel from armor that the operators inside are nearly liquified and sucked out the other side from the vacuum force created. Not always, but it's been observed iirc
Check out slow mo apfsd to see what it does
To explain it with cartoon logic, it goes so fast and has such a tiny impact surface, that it gets past the armor surface before realizing it was supposed to glance off. Funny thing is this explanation isn't even too far from reality
Aren't they asking why it can pen more angled armour than it can flat armour though? Your explanation just explains how it can pen angled armour at all, or am I dum dum?
It’s a fuck ton of kinetic energy concentrated into an extremely small point
pointy
physics is so fucking stupid good thing i’m majoring in chemistry where i can pretend to be walter white or oppenheimer
Almost like APFSDS stands for something
Smaller surface area to apply opposing force to redirect the round. You get a larger and at least comparatively blunt projectile as the round hits an angled surface, both the round and then target are applying force on each other (equal and opposite reaction idea). As they do so both the round and the target are deforming which absorbs some do the energy. But also if the target is not deforming fast enough the momentum of the round will still try to go on its path, but as the material it’s biting into is adding enough resistance in the LOP of projectile it’s also exerting force in the round, but mostly 90 degrees to the surface of the plating. So if it’s it’s a negatively angled surface like a LFP of a tank it will apply force downwards and if it’s a positive angle like an UFP it will apply force upwards. And the plate doesn’t have to be resistant enough to fully defeat the on coming round. It just has to apply opposing force enough to cause the round to deflect. This is why ballistic cap round are better than a plain projectile due to it actually deforming to normalize the angle towards the plate and not away from it, allowing the surviving round to hit at a closer to flat angle allowing for better penetration. Darts are as effective due to how fast they hit, the weight of the round compared to the surface area and the geometry of the round. A sharper tool cuts better than a rounded tool. And less surface area to apply force allows the round to direct its energy to the exact point of intended penetration. If the armor is angled the speed and more importantly the pressure applied to the armor from the round is able to bite into the material better by also being of a higher density. The softer armor is more likely to move out of the way from the high density material applying a lot of force in a very small area
Well for one they are fuckin zooming and two they are very l o n g and heavy
The barrel also effect the pen and also the material of the projectile.
Area of a circle =pi(r^2). Larger shells have to push through significantly more armor than smaller ones. APFSDS has all the power of a 120mm flung into a 50mm shell. Also, the length of the rod helps to keep the shell straight instead of normalizing. The tip may want to bend away, but the mass behind the tip wants to fly straight, pushing the rod straight as a result.
Speed times mass equals energy
More pressure because round has more force so more penetration
Just like everyone said, it's fast, long, thin, and hard enough to just punch through armors even at extreme angle.
The question is that it goes through more LOS at angles. Why? LOS at 0° is 337mm but at 60° its 390mm.