Technical terms.

[Doug Beman]

What is meant by such technical terms as T/D ratio, obliquity, and the other stuff about tanks; particulary those concerned with gun vs armor resolution?

This site makes me realize how much I don't know. Don't know whether I should be galvanized or humiliated.

Regards,

DjB

[Fionn]

T/D ratio: This is a ratio of the thickness of the thickness of the armour to the diameter of the shell hitting it.

Basically lets presume penetration is determined just by kinetic energy and T/D (its not but this is just for explanations sake).

The greater the diameter of a shell for any striking Kinetic energy (determined by 0.5 times mass by striking velocity squared) the more it will penetrate due to mass effect.

The T/D ratio basically stated that if a 75mm diameter shell with KE = x penetrates 60 mm of a 100mm thick armour plate than a 125mm diameter shell with KE=x (the same kinetic energy) will penetrate 70 or 75 mm (just rough figures) of the 100 mm plate.

Why? Well I won't get into the maths BUT it is due to the appearance of overmatch phenomenon which occur when the diameter of the shell is greater than the linear thickness of the armour.

Of course it doesn't just kick in when diameter is greater than thickness but operates on a sliding scale at all values.

It's really a pretty complicated issue and not too many people are even aware of it, nevermind understand it...

It'd be an interesting thing to explain one day no?

Obliquity... basically this refers to a shell hitting an armour facing from the side (in other words at less than right angles).

The effect of obliquity is to add a SECOND component to armour angling. No longer is the armour just sloped from the vertical it is also, effectively sloped to the path travelled by the shell.

Thus obliquity provides some level of 3-dimensional ballistic protection.. However obliquity depends on your enemy being poorly positioned with the effect that most tank designers prefer to depend on 3-dimensionally rounded hulls and turrets.. Look at the M-48 hull and turret and the IS-3 turret for good examples of this.

Chobham armour can only be manufactured in big straight plates so Western nations have abandoned rounding in favour of sheer thickness and protection these days.

It all gets terribly complex and one would really need graphs to explain it all properly in a step by step manner. Someone should do such a series of articles one day.

[Rick]

Fionn,

Presuming you'll see this.

Do you do explanations like that often. It was quite impressive.

[Fionn]

Oh yeah ..

I generate at least 1 multi-page explanation per day ... I'm a regular ahem poster of long answers on the TGN SP format. And pretty soon more of my REALLY long explanations of stuff will be up on The Wargamer .

Thanks Rick

[Rick]

Might've been a little long, but at least now I understand, very clearly as a matter of fact.

[Fionn]

Glad to be of help

P.s. That was the REALLY short version. Lots of things I said are only approximations of reality but the real equations literally are the subject of engineering doctorates.. (I'm no engineer ehe)

[Rick]

I've always thought that Obliquity, of course before i didn't know what it was called, would change many combat results in games like this. I've always wondered if such a thing would ever be modeled in a game, seems like it would be a particulary hard thing to model.

[Guest John Maragoudakis]

Fionn, do you forsee any changes to the wargamer since imagic has bought it?

<BLOCKQUOTE>quote:</font><HR>I-Magic To Acquire The Wargamer by James Fudge Posted 06/03/1999

Interactive Magic announced today that it will acquire The Wargamer,( www.wargamer.com ) an Internet destination dedicated to military history, strategy games, and military simulations. The acquisition reflects Interactive Magic's continuing strategy to acquire additional Internet Entertainment Communities.

"This is a great alliance for both Interactive Magic and The Wargamer," said Interactive Magic CEO J. W. Stealey. "This strategic move will be beneficial to both of our companies and is the latest in a series of steps designed to build our global Internet Entertainment Communities. New customer traffic, website impressions and advertising revenue are all growing steadily at all of Interactive Magic's Internet Entertainment Community websites: The iMagic Entertainment Network (www.imagicgames.com ), GameHub (gamehub.net), and MPG-Net (www.mpgn.com ).

Most recently, Interactive Magic divested their PC CD-ROM business to french publisher UbiSoft in a move that the company sees as a focus on online activities. If you listen to the PR coming out of the company as of late, you'll notice that they talk a lot about web related business like impressions, unique visitors and traffic. It makes one wonder if I-Magic is getting out of the game business altogether and moving towards the online entertainment business.

For now the answer is no. The company still holds some online game titles, as well as game portal sites like GameHub that have their own unique game offerings. But the company is certainly moving towards becoming a new beast with this latest acquisition.<HR></BLOCKQUOTE>

[This message has been edited by John Maragoudakis (edited 06-04-99).]

[Fionn]

Rick,

It is my understanding that, yes it is modelled. At least from Moon's reports on the game (since he's the only one whose seen it yet) it is modelled. Go to The Wargamer and read his battle report. You will see that a round from an 88mm ricocheted off a Sherman due to the effects of 3dimensional sloping.

P.s. Steel Panthers only takes into account "Effective Thickness". It doesn't deal with ballistic protection never mind 3dimensional obliquity effects. CM does. Enough said .

John, hehe I see I've been effectively ambushed. For those that don't know it I am currently the Historical Editor at The Wargamer.

Quite honestly, the deal isn't fully done yet. Details do need to be dealt with and while I can't see it breaking down at this stage I CAN catch a beating from the site owner for speaking in public about it so I'm gonna do something I VERY rarely do and keep relatively quiet .

What I will say is that things will become clearer only with the passage of time. (Gees I'm good at the cryptic clues amn't I? ).

[Guest Big Time Software]

Rick, all this stuff and MORE is simulated. That is what 3D physics, lots of research, dedication, and slick programming can get you Fact is, the armor penetration/ballistics part of CM is the technical element we are most proud of. To see a partial list of the things simulated, check out the Resources section of the Combat Mission area on our site. Scroll down to the bottom and you will see a link to penetration charts.

Steve

[Rick]

Just one Question:

It does take some really heavy math to simulate such things, don't it?

By the way, the more I hear the more anxious I get. It will be nice to finally see a wargame which will portray the face-off between axis and allied armor accurately. I've been told and kind of observed it myself, that since most games only simulate firepower and armor protection to any reasonable degree of realism, they make American armor and even some German vehicles as being worse than they were. I've been told that the Sherman's virtues included things like reliability, high rate of fire, good visibility, and a fast turning turret. None of these things are simulated well and some not at all in most games and thus the Sherman sucks in most games. I realize the Sherman wasn't as good as the Panther but some games make it look so much worse that it's hard to believe we won the war.

[Guest Big Time Software]

Heavy math? Let's put it this way... I told Charles that if he tried to explain it to me I would quit

You are SOOOO right about the penetration and ballisitics stuff. I have never found a game where I have felt that these things were modeled correctly. The others stuff, like turret rotation speed, max/min gun depression angles, etc. are sadly lacking as well. Well, except in CM

BTW, we just put in the Sherman "Jumbo". Its gun is still only so-so, but MAN can it take the hits. I think it has something like 150mm of armor on the turret. Good thing for the Germans that only a couple hundred were built! Buggers can take out a PzIV J no problem. Trust me... Even my Panther had a hard time with one, though my Jagdpanther clocked his target on the first shot

Steve

[Fionn]

Rick,

That whole, Front Armour = 6, Side = 4, Rear = 2 is so simplified its not even funny.

Hell a lot of games out there only have front, side and rear armour ratings, averaging out the armour ratings of hull, superstructure and turret for simplicities sake.

Those which do have several ratings generally only have turret and hull ratings and even then they usually forget to account for ballistic protection effects.

Even the best of them seem to forget about obliquity and the effect of angle of incidence on shell penetration and actions.

I even know of a well-known tank simulation which did NOT model the effects of the manual-only turret traverse on the Pz IV J which slowed its rate of traverse right down to about 7 degrees per second (that's a little bit of a fudge for the game but that's the value it now uses instead of 14 degrees per second).

Anyways the Sherman Jumbo was built like a fortress. It had huge armour (heavier even than the Tiger I in many places) BUT unfortunately its gun sucked (yes that IS the technical term used to describe its performance) and anything bigger than a 75mm L/48 could take it out. Panthers had a little difficulty but the good old 88s went through it relatively easily. It was just another lesson to the Allies that it was no point having well-armoured tanks with VERY poor guns and well-armed tanks with poor armament. Better to have good armour and good gun in one.

There was no reason why the Allies couldn't have made an equivalent to the Panther. It only didin't happen because of doctrinal issues.

[Rick]

I can't wait to see the differences this more detailed approach makes in the actual game-play. It sounds to me that this detail means that this program has complex algorithms running under the hood on the order of something like Photoshop, or other image-editing software. This game probably could not have run quick enough to be a game not too long ago.

As far as the doctrine goes, I sure am glad I was never a WWII tanker. It would be much more comfortable to be a US tanker now, when the M1A2 is amongst the most well protected and powerful tanks on the battlefield. There's no way I could be a tanker though, when I was in JROTC we went on tours, one of which put us in an M60 for a while. No way my 6'5" body could feel comfortable in a sardine can like that.

[Guest Big Time Software]

Rick, a military vehicle collector (or was it a tanker Charles and I met?) told me a story about someone around your size that got STUCK in a hatch of some small armored vehicle. Pretty sure it was a Ferret (British armored car). The guy wasn't overweight or anything, just big. Guess you aren't well suited to planes, AFVs, or subs, eh?

Steve

[Rick]

No, I'm definitely not suited to vehicles with cramped interiors like that. My size was actually an important factor in choosing my truck.

However, my size helps me carry a great deal of camera gear into the field.

[Pixman]

All this stuff is great. It is why I have always looked forward to a computer game that could automate all of the calculations and probabilities, while leaving the player's mind free to plan strategy and tactics. Squad Leader, while a great game, intimidated many of my potential opponents by sheer weight of the compounded math.

But here's the rub. Many of them (one in particular that I will address in a minute) got too caught up in all the math. The people who excel at CM, as with SL, will be those who can quickly intuit the game. It is the inate ability to instantly model the multiple layers of abstract, three dimensional geometry in one's head that makes the great squad level game player. This player does things intuitively, just because they seem to make sense, not because the numbers indicate his choices should work.

I have a very good friend from college who is a world class research scientist. He did primary research on Nuclear Magnetic Resonance (known now as MRI) and has been published numerous times in the Journal of Science. He is brilliant and very good at thinking "out of the box" as well. He, like I, was addicted to Squad Leader. Yet, while mathematically brilliant, he was never able to beat me. He would consult the charts, calculate the probabilities in his head, do "what if" analysis and still make what I knew at the time were suboptimal moves.

I am not saying I am the best at intuiting these games because I have met better and had my lunch eaten (by people worse in math than I). I am just trying to point out that, when it comes down to game time, the numbers won't mean a rip in determining who wins or loses. What the numbers do, and I applaud BTS for doing this so well in CM, is make sure the game engine accurately models realistic resolutions to the joint decisions of the two players.

But the winner will invariably be the person who knows when to hold and when to fold, when to fire and when to move, where to place his crew weapons, how to position his leaders, how much critical mass of men it will take to assault that building, take the shot on that Tiger or not, etc. The numbers will just serve to reward him/her for those decisions.

[Guest Big Time Software]

Well put Pixman! Unfortunately for many Grognards, both their sense of math AND inutition will be greatly disturbed by Combat Mission. Because it simulates everything so realistically, where NO other wargame does (the armor stuff in particular), many Grogs are going to have to UNlearn what they have come to think of as "fact" and "truth". See new thread for an example.

Steve

[Wesy]

Although this applies to Naval Gunfire, it might be relevant to AFV...Really interesting calculators (measure obliquity and armor penetration and good website to boot.

http://www.skypoint.com/members/jbp/gunarmor.htm