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chuter

PUBG physics

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I was tooling down the road at speed in a panzer 4 when i got hit by a T34 from about 1200m and 11 o'clock the round striking the lower left hull towards the idler.  No damage from the shot but the tank spun around to the left one and a half turns while flipping upside down ...

 

Seriously, there shouldn't be much noticeable impact recoil at all let alone this.

 

PS.  Growing weary of turning T34 STZ* into a giant sieve with solid shot with little effect and it often taking a couple or more APHE. 

*I wonder why it continues to be so popular?

 

The game is a work in progress, I know.

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15 minutes ago, chuter said:

Seriously, there shouldn't be much noticeable impact recoil at all let alone this.

 

What makes you think that? Recoil would be roughly the same as in the firing tank minus the energy lost due to drag. So even if you end up with half the original energy that could make you slip and your kinetic energy does the rest.

 

The regular T-34 and Pz.III are too tough ingame, that should get some revision IMHO.

Edited by 216th_Jordan
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In a   " Fantasy "  world IL2 Great Battles, etc,   this  is called physics.

 

In the real world, it's not called  physics,  but simply fantasy.   The kinetic energy from a 76mm round  striking a 25T tank doing full speed  @ 25MPH,  would not cause it to do a 540.

 

Anyways, you don't even need to get struck by a round  to do that,   take a PIV,  @ 25T    or a TIger @ 54T   drive up a road full speed,  again @ 25MPH  and turn too fast,  and you can do a 540 or a 720.   Real world,    this is impossible,  but not in fantasy, where it  happens  routinely  .

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26 minutes ago, JG1_Wittmann said:

In the real world, it's not called  physics,  but simply fantasy.   The kinetic energy from a 76mm round  striking a 25T tank doing full speed  @ 25MPH,  would not cause it to do a 540.

 

The kinetic energy of the tank makes it spin because the kinetic energy of the round pushes the tank enough to lose grip and move over to friction (friction coefficient is always lower than grip coefficient) causing the spin, which would be your second argument. A tank not moving does not spin when impacted in Il-2 and tbh I've never spun when being hit.

 

If a tank would spin on or not when going fast and initiating a rotation I can't tell you, but I consider it at least plausible when 30 tons go more than 40 kph on steel tracks.

 

Here two examples:

 

Spoiler

 

 

 

Spoiler

 

Edited by 216th_Jordan

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Those examples  appear to be 2 tanks, doing well in excess of 25mph,   and on asphalt.   I'm not aware of any asphalt roads in game.  The first one does a 180,   and it appears, hard to see that the right track is locked, causing the spin,  likely intentional.  The second video, the driver clearly locks up the right tread after braking ( clear to see as the front noses down) and the spin starts.   Again, asphalt or concrete.  This does show it is plausible at that speed on concrete or asphalt,  intentional or not. This does not show that it is plausible,  due to speed, and road surface/dirt or in a field.

 

So yes,  if we could go faster than 25mph, and internationally  locked a track it could spin.   Possibly even 180.  Take a tank out for a spin on a dirt road and do a quick turn then   see how far you went in degrees.  

 

Lastly, and why yes, this is still a work in progress,  the Tiger used a double differential, so unlike the Russian tanks that used clutch/braking to turn,  that is not how the Tiger operated in reality, but that is what we currently have in game at the moment.

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6 hours ago, JG1_Wittmann said:

and on asphalt.

Even more, wet asphalt, which makes it much worse.

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I used the videos to show how inertia works on such heavy machinery once they start to slip, not exactly to show how the game should simulate it.

 

So there are a couple of points in my head:

1.) Without a video of the issue it does not make much sense to discuss if it would this simulated behavior is real.

2.) I'd expect gravel roads to offer lower grip than asphalt in dry (!) conditions and I'd expect dry gravel roads to offer slightly more grip than wet asphalt. (However I admit that I don't have a clue on this and am just guesstimating from my experiences)

3.) Every tank is different, today's tanks are built with a comparatively low profile compared to their width and length, giving them more stability. Then there is chain size, then there is chain design, shifted center of gravity, and so on and so forth. So evaluation would need to be done on a per tank basis

4.) Expanding on #3 I have never spun a full 360 in Il-2, but then again I don't use the Panzer 4 often. Hence a video would be nice (#1)

 

Edited by 216th_Jordan

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If you want to talk about silly physics, hit one of the free tanks with a Yak-1 ser. 69. Sucker will go flying like a tossed rock.

 

I remember the first time it happened to me, I was in the Pz.III L on the outskirts of a forest. Dude rammed me, and I got launched into a bunch of trees and exploded. :lol:

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Not sure if that is so silly.

Quick estimate: Let's assume a Yak at 360km/h =100m/s with a weight of 3000kg (just guessing that now... ) hits a tank with a weight of 40000kg.

Impulse: v_tank = (m_yak x v_yak)/(m_tank) = 3x10^5/4×10^4=7.5m/s (close to 30 km/h)

 

Let's try to lift the tank and convert the kinetic energy of the yak into potential energy for the tank:

1/2×m_yak×v_yak^2=m_tank×g×h: h=0.5×3×10^3×10^4/10/4×10^4=37.5m

 

I am aware that certainly there will not be a perfect transfer of impulse and energy, but I'd think this shows that the ooompf contained in a yak hitting a tank is far from negligible.

Edit: I just made this up quickly here on the phone, please check :)

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The weight of the Yak doesn't count that much, because most of its energy gets lost in the deforming of the Yak. What really counts is the engine, which will not be deformed very much.

I remember when in Germany the nuclear power plants were planned, they were planned to withstand a crash of a Phantom fighter, however a Boeing 747 was of course much larger and heavier. But the really important point were the jet engines, which would not be deformed very much and here the Phantom was the most dangerous aircraft.

Most of the Yak will just pass the tank without giving a lot of energy to it. Dangerous are mainly the engine and the fuel.

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Just looked it up, a Klimov 105 alone, dry is almost 600kg. That would then be enough to move it to 6km/h or lift it to 7m. Still shows the impact should be able to move a tank, more than just shaking it, which is all I wanted to say. It's just not a priori a silly thing to assume an impacting plane could move a tank.

I am also not so sure if deformation will really totally consume the kinetic energy of the rest of the plane. Where does the momentum go? If you assume stuff is reflected backwards  doesn't that imply there is at least an elastic component in the crash, and therefore not all the energy going into deformation? 

Edited by No.322_Nocke
correcting the auto correction...

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I've hit a lot of tanks since the last patch and I can say that the physics have been very realistic.  I'm sure there are anomalies in the coding, it's a huge undertaking but the flukes shouldn't ruin the game for anyone.  I remember that guy that used to do videos of bizarre physics with the aircraft within this game...little glitches that he would purposely find and highlight.  It can be entertaining for some and yet it does help the devs perhaps make some corrections.  But overall....I love this game and the direction it's going.  I'm usually using the 88...but I haven't had many T-34's around long after a hit these days.

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18 hours ago, No.322_Nocke said:

If you assume stuff is reflected backwards  doesn't that imply there is at least an elastic component in the crash, and therefore not all the energy going into deformation? 

No this definitely not. My guess is the Yak would break apart and be spread all over roughly in flight direction.

BTW. part of the question, if the aircraft would be able to move the tank, is the question in which angle the aircraft hits. If it hits more or less horizontally, the chance of moving the tank is much higher than with an impact at a high angle, where the tanks suspension most likely would break, but the tank itself gets more pressed to the ground instead of being moved along it.

And of course it depends on the tank. A Panzer III is much more likely to be moved than a Tiger.

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Well, Klimov engine itself is a nice ~600kg projectile 😁

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