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SPG Shell Arc

SPG shell arc mechanics physics

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Fireholder1 #1 Posted Jan 17 2019 - 14:09

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A kid tried to convince me that angling the front of an SPG upward will increase the shell arc (i.e. provide a higher shell trajectory and larger impact angle).

Discuss.

cKy_ #2 Posted Jan 17 2019 - 14:12

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"Kid"

FrozenKemp #3 Posted Jan 17 2019 - 14:21

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Well... yes. If your SPG is parked on an up-slope, that will increase both the minimum and maximum angles available to your artillery. That can be good and bad.  For instance, it increases your minimum range - it might be that even at lowest elevation your shot will go clear over a target. 

GeorgePreddy #4 Posted Jan 17 2019 - 14:30

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View PostFireholder1, on Jan 17 2019 - 10:09, said:

A kid tried to convince me that angling the front of an SPG upward will increase the shell arc (i.e. provide a higher shell trajectory and larger impact angle).

Discuss.

 

The physics couldn't be more simple, if you point your gun at a higher angle by parking on an upslope, your shell arc will have a higher apogee which would equate to a larger (less shallow) angle of impact.

 

What did we learn ?  Maybe that not all kids are dumb.

 

 

 

 

 

 

 



Vava_das_SPGs #5 Posted Jan 17 2019 - 15:04

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There's a limit of angle that the vanilla can calculate the aiming recticle when the SPG is angled upwards (that also happens on the normal aiming at very long range of shallow shell arc, on huge maps, as Grand Battles). I don't have the formula, only the day-by-day experience.

Also... there's an illegal mod that can turn a shallow shell arc spg, when angled upwards, as a very high arc, low range spg. That's an illegal mod and anyone using it should be banned.

Dab_3_For_Balance #6 Posted Jan 17 2019 - 15:11

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It literally works that way lol

13Jake55 #7 Posted Jan 17 2019 - 15:16

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In real life it results in a higher trajectory and therefore you are able to shoot over or behind obstacles.  It also results in a longer flight time. In game when you do this the aiming circle starts to get screwy. Using slight slopes is ok but major slopes can mess with your aiming circle.  If uou want a high arc get the SU5 mortar. I love plopping shells on unsuspecting  tanks hiding behind building.

ATruk #8 Posted Jan 17 2019 - 15:27

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View PostGeorgePreddy, on Jan 17 2019 - 06:30, said:

 

The physics couldn't be more simple, if you point your gun at a higher angle by parking on an upslope, your shell arc will have a higher apogee which would equate to a larger (less shallow) angle of impact.

 

What did we learn ?  Maybe that not all kids are dumb.

 

 

 

 

 

 

 

 

I think you answered a different question. This question was about the “front of the SPG”. Aiming goes wonky when you actually do that. 

MI_LAD #9 Posted Jan 17 2019 - 16:24

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if only they could make spg shell arcs even remotely realistic 

_ShakeNBake_ #10 Posted Jan 17 2019 - 16:40

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If you are limited by the gun elevation then yes. The ballistic arc of the shell is determined by the angle of the gun. The angle of the hull is irrelevant as long as you are still within the gun constraints. Are there any arty with <45* max gun elevation?

_ShakeNBake_ #11 Posted Jan 17 2019 - 16:41

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View Postnorthlife, on Jan 17 2019 - 08:24, said:

if only they could make spg shell arcs even remotely realistic 

 

They are accurate parabolic trajectories, just given the gravity of Jupiter.

heavymetal1967 #12 Posted Jan 17 2019 - 17:10

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View PostV_A_C_A, on Jan 17 2019 - 09:04, said:

There's a limit of angle that the vanilla can calculate the aiming recticle when the SPG is angled upwards (that also happens on the normal aiming at very long range of shallow shell arc, on huge maps, as Grand Battles). I don't have the formula, only the day-by-day experience.

Also... there's an illegal mod that can turn a shallow shell arc spg, when angled upwards, as a very high arc, low range spg. That's an illegal mod and anyone using it should be banned.

 

If, key word, that's the one I'm thinking about (there were several forum threads when it was discovered) they patched the game and broke it.

 

Back to the angling part.  The front of the SPG isn't what needs to be angled as much as the gun.  It works "better" on SPGs with guns farther to the rear, but the change isn't as noticeable.

 

What you want to do is increase the elevation of your gun a bit, not necessarily the front of the piece.  But the "kid" likely meant gun cause usually angling the front of the arty will increase the gun's elevation.  But the gun is what needs to be angled over it's normal limits.

 

Also doesn't need to be a hill.  Parking far enough back on a berm or a destroyed object is one way.  It won't give as big/noticeable a change though.   Also you can over compensate for lack of a better term and gob your shots off entirely.  

 

No different than parking far enough forward on something or backing up a small rise/debris will lower your gun giving you better depression to shotgun someone.

 

And this is more of a benefit with arty that already have high arc/higher gun elevations.  But again it will increase your minimum range  and cut down your max range per Frozen Kemp.  It's actually better in short range arty.  If you're near or at your max range it'll allow you to drop the rounds nearly straight down.  Good for hitting turret tops and engine decks at a good angle.

 



Almighty_Johnson #13 Posted Jan 17 2019 - 17:11

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View PostGeorgePreddy, on Jan 17 2019 - 08:30, said:

 

The physics couldn't be more simple, if you point your gun at a higher angle by parking on an upslope, your shell arc will have a higher apogee which would equate to a larger (less shallow) angle of impact.

 

What did we learn ?  Maybe that not all kids are dumb.

 

 

 

 

 

 

 

 

In Real Life physics, this would be a thing, sort of.  In order to complete a fire control solution to aim at a target the factors are projectile mass, propellent power, and gun elevation/direction.  Since in this game the projectile mass and propellant are fixed constants, the only adjustable factors are direction and elevation.  Elevation is a factor of elevation from a flat plane.  It doesn't matter what the angle of the gun carriage is at unless the requested angle is outside the elevation limits of the SPG.

 

So No.  Elevating the chassis of the SPG will have no effect on shell arc unless you force the angle past the limits of the vehicle 



Fireholder1 #14 Posted Jan 17 2019 - 17:14

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Lots of interesting comments here. Also, why the scare quotes around the word kid? He's literally a junior high school student. LOL

Fireholder1 #15 Posted Jan 17 2019 - 17:17

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Back to the point, it doesn't matter what angle your hull is at, the shell trajectory will never increase for a given distance; it will be the same height and angle of impact at that distance as if your hull were perfectly level.

heavymetal1967 #16 Posted Jan 17 2019 - 17:18

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View PostFireholder1, on Jan 17 2019 - 11:14, said:

Lots of interesting comments here. Also, why the scare quotes around the word kid? He's literally a junior high school student. LOL

 

Quotes cause you didn't qualify that in your initial post. 


Point taken and definitely a kid - quotes or not. :)

 

Spoiler

 



theSparatan117 #17 Posted Jan 17 2019 - 17:21

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View PostFireholder1, on Jan 17 2019 - 11:17, said:

it will be the same height and angle of impact at that distance as if your hull were perfectly level.

 

Not exactly. You can hit closer targets with a higher arc. However, the most unrealistic part of shooting Artillery (aside from the god view) is that you never have to calculate powder... so it's based solely on WG to calculate the power behind the shell ... 



Da_Craw #18 Posted Jan 17 2019 - 17:22

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View PostGeorgePreddy, on Jan 17 2019 - 07:30, said:

 

The physics couldn't be more simple, if you point your gun at a higher angle by parking on an upslope, your shell arc will have a higher apogee which would equate to a larger (less shallow) angle of impact.

 

What did we learn ?  Maybe that not all kids are dumb.

 

 

 

 

 

 

 

Maybe.  Because WoT shells use a fixed charge, there are only 2 firing solutions that will hit a given target; one at a greater than 45 degree angle and one at less than 45 degrees.  The Sturmpanzer II has a maximum elevation of 75 degrees.  Theoretically, if you park with your hull at a 15 degree slope, you could shoot straight up.  Guess I'll have to try that.

View PostEdgarAllanCrow, on Jan 17 2019 - 08:11, said:

It literally works that way lol

Only for firing solutions that are otherwise outside of the gun constraints.

View Post13Jake55, on Jan 17 2019 - 08:16, said:

In real life it results in a higher trajectory and therefore you are able to shoot over or behind obstacles.  It also results in a longer flight time. In game when you do this the aiming circle starts to get screwy. Using slight slopes is ok but major slopes can mess with your aiming circle.  If uou want a high arc get the SU5 mortar. I love plopping shells on unsuspecting  tanks hiding behind building.

Sturmpanzers are similar.



Byracki #19 Posted Jan 17 2019 - 17:43

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Too many people talking about real life SPGs

No one gives a flying crap about real life in this arcade game

 

In the game, driving up a slope to raise your front hull does nothing on almost all SPGs.

If sitting your hull on flat ground you can hit a target with your gun at 25° elevation... at that same location with your hull on a 10° up-slope, your gun barrel would lower to 15° elevation to accommodate the shot. The game does this automatically. You gain nothing by using an up-slope if you have enough elevation to make the shot originally.

 

There are, however, exceptions. If you are in a Bishop, the tier 5 UK arty, you ONLY have 15° of gun elevation. In this case, your gun will only point up 15° + however high you can point your hull. You could make the above shot if you could get your hull up 10°, but if you only find a 9° up-slope, the target will show out of range.


Edited by Byracki, Jan 17 2019 - 17:44.


SuckerPuncher #20 Posted Jan 17 2019 - 19:38

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View Postnorthlife, on Jan 17 2019 - 09:24, said:

if only they could make spg shell arcs even remotely realistic 

 

like tank HP, or repair kits, or resurrection med kits, or spotting mechanics, or armor penetration, or traction physics, or mythical tanks or... 





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