# Few questions about penetration and ballistics

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Hey guys,

I'm doing a  project about tanks, right now ballistics and penetration specifically. I need your help to understand several things. If someone could explain it would be greatly appreciated.

My first question: could someone explain these thickness T/D ratios? I don't really get them..

Thanks!

Edited by LordMustang

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It's exactly as it sounds: the thickness of the armor (T) divided by the projectile diameter (D). The way it works is that for a given projectile type, the wider shell is also heavier and is thus more resistant to force, including the natural force armor exerts on anything trying to bypass it.

Also, why are you asking for help in the WT forums out of all places? You're better off doing a project on water supply lines using Info Wars as a source.

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4 minutes ago, Nope said:

It's exactly as it sounds: the thickness of the armor (T) divided by the projectile diameter (D). The way it works is that for a given projectile type, the wider shell is also heavier and is thus more resistant to force, including the natural force armor exerts on anything trying to bypass it.

Also, why are you asking for help in the WT forums out of all places? You're better off doing a project on water supply lines using Info Wars as a source.

Because I do have the sources, but I sometimes misinterpret books, and I know there are guys on the forums that know their way around with the equations pretty well. I hope you don't mind it that much.

Edited by LordMustang

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IIRC  there is a really good book called Theory and Design of Guns and Ammunition  think its the second edition one , it has some good illustrations that will probably help you out , ummm i cant remember what's in there to be honest  exactly but dose cover and explains things of this nature

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Quote

My first question: could someone explain these thickness T/D ratios? I don't really get them..

Im not sure you are in a right place.

Remember that the book is written as a guide for wargaming (mostly), so I guess if you are writing a serious paper, you need some serious physics books.

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T/D is the thickness of the armorplate divided by the diameter of the shell, so 3,81cm/5,7cm = 0,67. I guess it's used because you can roughly compare all APCBC shells with one another, so if you look at a 75mm gun with an impact velocity of 2610fps you could say that it has a T/D of 0.67 too, which means it would penetrate 5,025cm of steel angled at 60°. I have no clue how that would benefit you, but i assume you can draw a graph in a diagramm with velocity and T/D so that you can just read of what a certain gun with a certain velocity would punch through.

Edited by Hardmoor
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4 minutes ago, Ulatersk said:

Im not sure you are in a right place.

Remember that the book is written as a guide for wargaming (mostly), so I guess if you are writing a serious paper, you need some serious physics books.

No, it isn't a very serious paper. It just needs to elaborate the basics of angling, deflection, armor hardness and such. Problem is that I can't really find much about deflection and shell shattering in the WWII ballistics book.

2 minutes ago, Hardmoor said:

T/D is the thickness of the armorplate divided by the diameter of the shell, so 3,81cm/5,7cm = 0,67. I guess it's used because you can roughly compare all APCBC shells with one another, so if you look at a 75mm gun with an impact velocity of 2610fps you could say that it has a T/D of 0.67 too, which means it would penetrate 5,025cm of steel angled at 60°. I have no clue how that would benefit you, but i assume you can draw a graphin a diagramm with velocity and T/D so that you can just read of what a certain gun with a certain velocity would punch through.

Thanks!

Edited by LordMustang

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2 minutes ago, LordMustang said:

Thanks!

I have to say that i am not a native english speaker, that was just how i would interpretate it.

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24 minutes ago, Hunternz said:

IIRC  there is a really good book called Theory and Design of Guns and Ammunition  think its the second edition one , it has some good illustrations that will probably help you out , ummm i cant remember what's in there to be honest  exactly but dose cover and explains things of this nature

I've already tried to find that book, but it doesn't seem to be available on the internets. Purchasing it will become a tad expensive...

Just now, Hardmoor said:

I have to say that i am not a native english speaker, that was just how i would interpretate it.

Me neither, and I had even more problems interpretating it, so you still did a good job.

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5 minutes ago, LordMustang said:

I've already tried to find that book, but it doesn't seem to be available on the internets. Purchasing it will become a tad expensive...

Me neither, and I had even more problems interpretating it, so you still did a good job.

should be enough in there without purchase :))

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1 minute ago, Hunternz said:

It's only a preview

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Just now, LordMustang said:

It's only a preview

500 odd page preview , but it should cover what info you needed

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2 minutes ago, Hunternz said:

500 odd page preview , but it should cover what info you needed

For me it isn't 500 pages? Only like 30-40 or something.

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3 minutes ago, LordMustang said:

For me it isn't 500 pages? Only like 30-40 or something.

oh lol .. seems i have miss lead you im sorry , but still should have what you need , well i hope , if not i maybe be able to source it else where will need to send an email to freind

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1 minute ago, Hunternz said:

oh lol .. seems i have miss lead you im sorry , but still should have what you need , well i hope , if not i maybe be able to source it else where will need to send an email to freind

Don't bother, thanks for your effort though. I don't think I'll need it. I will keep my project basic and just explain it according to simple models and equations. If I was going to take all the things into account mentioned in the Ballistics: Theory and Design of Guns and Ammunition book, then my project would exceed well over the hundreds of pages. I'll try to summarize some of the info.

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2 minutes ago, LordMustang said:

Don't bother, thanks for your effort though. I don't think I'll need it. I will keep my project basic and just explain it according to simple models and equations. If I was going to take all the things into account mentioned in the Ballistics: Theory and Design of Guns and Ammunition book, then my project would exceed well over the hundreds of pages. I'll try to summarize some of the info.

ok freind good luck