48 replies to this topic

[JakeTehPwner]

How much force does an AC/20 shot have behind it(disregarding the explosive warhead)?

Then do the rest of the ACs if you want

I wanna see some of the physics behind MWO!

[stjobe]

How could one possibly calculate the force of an unknown-diameter gun with an unknown-weight projectile travelling at an unknown speed? And possibly being an abstraction of an unknown number of projectiles?

Not to mention it's a sci-fi weapon in a video game so it has exactly zero force. Or if you prefer, exactly whatever force its programmers decided to simulate.

Either way, take a guess. It's not going to be any less wrong than any other guess.

Edited by stjobe, 15 December 2012 - 02:45 PM.

[MoonUnitBeta]

e=mc2

[Mister Blastman]

MoonUnitBeta, on 15 December 2012 - 02:46 PM, said:

e=mc2

No, f=ma

[stjobe]

Mister Blastman, on 15 December 2012 - 02:50 PM, said:

No, f=ma

Actually, it's E_k=0.5*m*v². Since both mass and velocity are unknown, we cannot calculate E_k.

Edited by stjobe, 15 December 2012 - 02:58 PM.

[Karr285]

sure Ill bite,

F=MA (force = mass X acceleration) Mass of an aC 20 shot = 1ton/7 = 142.85KG

Acceleration = change is velocity / time now im gonna be lazy and since its velocity is 750m/s (and its a game so it goes from 0-750 and never changes) and max range is 270 ill just use those 270/750 = 0.36seconds travel time

so acceleration 750/0.36 = 2083.33
Force = 2083 x 142.85
= 297604.16

yay for imaginary numbers!

[Alek Ituin]

stjobe, on 15 December 2012 - 02:53 PM, said:

Actually, it's E_k=0.5*m*v². Since both mass and velocity are unknown, we cannot calculate E_k.

Also, we don't know the rounds air resistance and how much speed it loses over distance. Another problem as well is the fact that all AC rounds appear to be APFSDS, which means all muzzle velocity calculations are moot seeing as how APFSDS darts ACCELERATE after the sabots discard.

[JakeTehPwner]

Karr285, on 15 December 2012 - 03:01 PM, said:

sure Ill bite,

F=MA (force = mass X acceleration) Mass of an aC 20 shot = 1ton/7 = 142.85KG

Acceleration = change is velocity / time now im gonna be lazy and since its velocity is 750m/s (and its a game so it goes from 0-750 and never changes) and max range is 270 ill just use those 270/750 = 0.36seconds travel time

so acceleration 750/0.36 = 2083.33
Force = 2083 x 142.85
= 297604.16

yay for imaginary numbers!

Woot that works!

[stjobe]

Alek Ituin, on 15 December 2012 - 03:03 PM, said:

Also, we don't know the rounds air resistance and how much speed it loses over distance. Another problem as well is the fact that all AC rounds appear to be APFSDS, which means all muzzle velocity calculations are moot seeing as how APFSDS darts ACCELERATE after the sabots discard.

v can as easily be impact velocity as muzzle velocity. The formula works for both.

We still don't know either of the terms though.

[Alek Ituin]

Karr285, on 15 December 2012 - 03:01 PM, said:

sure Ill bite,

F=MA (force = mass X acceleration) Mass of an aC 20 shot = 1ton/7 = 142.85KG

Acceleration = change is velocity / time now im gonna be lazy and since its velocity is 750m/s (and its a game so it goes from 0-750 and never changes) and max range is 270 ill just use those 270/750 = 0.36seconds travel time

so acceleration 750/0.36 = 2083.33
Force = 2083 x 142.85
= 297604.16

yay for imaginary numbers!

Your mass calcs may be off. If infact the AC rounds are APFSDS as the art suggests, then you aren't taking into account the discarding sabot part of Armor Piercing Fin Stabilized Discarding Sabot. That means you are assuming the dart plus sabot are hitting the target.

[Murphy7]

Sorry Karr285, but answers without units aren't really answers (Newtons, I know). Significant figures are suspect as well.

[Alek Ituin]

stjobe, on 15 December 2012 - 03:04 PM, said:

v can as easily be impact velocity as muzzle velocity. The formula works for both.

We still don't know either of the terms though.

but do you know the darts acceleration rate?

Edit: i'm reading that as Muzzle Velocity and Impact Velocity are the same for you. APFSDS has a lower Muzzle Velocity but then accelerates to have a radically higher Impact Velocity.

Edited by Alek Ituin, 15 December 2012 - 03:10 PM.

[Karr285]

Murphy7, on 15 December 2012 - 03:08 PM, said:

Sorry Karr285, but answers without units aren't really answers (Newtons, I know). Significant figures are suspect as well.

Im lazy oh well, and the numbers work fine, unless you can tell me why not. I mean maybe the shell casing itself weighs a substantial amount, but using the numbers I can find this is the closest you will probably get. and its make beleive, treat everything as it is in space or a similar 0g 0atmosphere environment, cuz I know the game doesnt take these into account bullet drop aside.

Edited by Karr285, 15 December 2012 - 03:14 PM.

[Nassej]

To be honest the original post is very misleading, are you talking about the force that was used to accelerate the projectile to obtain it's velocity or the amount of force the projectile will impart on the target?

Karr285, on 15 December 2012 - 03:01 PM, said:

sure Ill bite,

F=MA (force = mass X acceleration) Mass of an aC 20 shot = 1ton/7 = 142.85KG

Acceleration = change is velocity / time now im gonna be lazy and since its velocity is 750m/s (and its a game so it goes from 0-750 and never changes) and max range is 270 ill just use those 270/750 = 0.36seconds travel time

so acceleration 750/0.36 = 2083.33
Force = 2083 x 142.85
= 297604.16

yay for imaginary numbers!

The way you solved this was a bit off, first you assumed the velocity was constant across the the distance of 270m, giving you .36 seconds then you assumed that there was constant acceleration and force between when the projectile starts moving to when it reaches its final velocity at 270m.

[Biglead]

An example of the rating system: the Crusher Super Heavy Cannon is a 150mm weapon firing ten shells per "round" while the Chemjet Gun is a 185mm weapon firing much slower, and causing higher damage per shell. Despite their differences, both are classified as Autocannon/20s due to their damage output.


Do these numbers help any? Assuming that 150 and 185mm rounds have the same v as in real life? I guess?

Edited by Biglead, 15 December 2012 - 03:28 PM.

[stjobe]

Alek Ituin, on 15 December 2012 - 03:08 PM, said:

but do you know the darts acceleration rate?

Edit: i'm reading that as Muzzle Velocity and Impact Velocity are the same for you. APFSDS has a lower Muzzle Velocity but then accelerates to have a radically higher Impact Velocity.

No, I'm just saying that the formula is the same. If you want muzzle velocity, substitute that for v. If you want impact velocity, substitute that for v. They can be different as they like, but the formula is the same.

[Alek Ituin]

Biglead, on 15 December 2012 - 03:26 PM, said:

An example of the rating system: the Crusher Super Heavy Cannon is a 150mm weapon firing ten shells per "round" while the Chemjet Gun is a 185mm weapon firing much slower, and causing higher damage per shell. Despite their differences, both are classified as Autocannon/20s due to their damage output.


Do these numbers help any? Assuming that 150 and 185mm rounds have the same v as in real life? I guess?

a 150mm and 185mm would have drastically different Muzzle Velocities, Impact Velocities, and round mass

stjobe, on 15 December 2012 - 03:28 PM, said:

No, I'm just saying that the formula is the same. If you want muzzle velocity, substitute that for v. If you want impact velocity, substitute that for v. They can be different as they like, but the formula is the same.

Ahh, ok then, makes sense... i must have read your comment wrong.

[Belorion]

African or European AC/20?

[Biglead]

Belorion, on 15 December 2012 - 03:32 PM, said:

African or European AC/20?

American...

[Alek Ituin]

Biglead, on 15 December 2012 - 03:40 PM, said:

American...

I think he missed the joke...