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Jabo Jumpy Now, But Have Some Technical Questions


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Having seen the horrific potential of Jabos in the recent CMHQ special, I have a few questions and comments.

1. How does CM model blast and frag damage from an aerial bomb?

From what I can see, it looks like some sort of cookie cutter radiating outward uniformly from the explosion. As I recall from my military analyst days, though, a bomb delivered from low level (not vertical dive or medium/high level horizontal) doesn't arrive vertical to the ground and i tends not to go off until it's some distance into the ground (unless fuze extenders are used), thus masking much of the explosion and removing a considerable portion of the casing fragments from play as well.

These factors being the case, I would expect that the worst orientation vs. the bomb for a target to be in would be perpendicular to the bomb's longititudinal axis. This would put the target in both the densest part of the fragment pattern and on the primary blast axis as well. I would expect that the area in front of the bomb's nose would be relatively safe, while the area behind the bomb would probably not be a major frag hazard, caused by narrow shape discharging upwards, but would be from the standpoint of blast, considering the bomb's tail is almost certainly out of the ground at detonation.

Also, as I recall, blast falls off very rapidly as a function of distance (forget exact mathematical relationship), while shell and bomb fragments, some quite large, have been known to travel hundreds of yards and do all kinds of damage to men and materiel.

Taken in aggregate, the issues I've raised would appear to argue strongly against the bomb explosion pattern as depicted in the special scenario on CMHQ. I would further argue that crater evidence tends to support this view, in that even Army manuals show artillery craters as being oval, while mortar craters tend to be more circular, the result of a more vertical delivery angle. A bomb would be hitting at an even shallower angle than tube artillery does, thus accentuating this oval aspect in the crater.

1a. How detailed is the CM bomb blast/frag model when it comes to representing and properly distinguishing the effects of the factors I've described above?

2. Though the article mentions 2.75" rockets, the ones which the British used with such devastating effect from their Typhoons were not 2.75s but 60 lb. rockets (warhead weight), something much nastier. Remember that a rocket doesn't have to undergo the 100,000 G load that a cannon shell does. Its HE fill percentage is therefore much higher than an equivalent weight artillery shell, so for a given warhead weight, the rocket puts much more HE on target than does the shell.

Which rocket is CM modeling, and what are its warhead details?

Seems like there's another question, but I'll post later if I think of it.

Regards,

John Kettler

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I just remembered the other item I wanted to mention. That is that the available film footage I've seen of bomb drops shows that most of debris goes up (not out) in a fairly acute cone, thus confirming the blast and frag masking I described in my initial post.

My apologies for the typo in the first post.

Regards,

John Kettler

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Guest Big Time Software

Bombs blasts in CM are circular. smile.gif

Not because I think you're wrong. In fact what you wrote appears to make sense. The problem is that I haven't come across any mathematical equations or other hard evidence to use as a basis for creating a more complex treatment of explosion patterns. I don't want to make things up (I'm not a chemical engineer, after all) so for now, at least, I'm keeping it simple and using an even circular pattern. However, if you know of a good source for information of this sort - something I could base algorithms on - please let me know and I'll look into it. Sorry I wish I could give you a better answer.

As for bombs craters being oval, I think that the extra "length" of the crater due to the kinetic energy and direction of the bomb's flight path (which makes the crater "long") might be balanced out by the fact (?) that, due to the bomb's shape, more explosive power is sent out to the sides (?). So it would end up being a rough circle. That's just my guess, though.

CM's fighter bombers use the 60lb. HE rocket you mentioned. They do a pretty good job of knocking out tanks and other vehicles. It's also very cool to watch them come streaking in and pow! Yes, even in a "serious" game like CM sometimes it's fun to watch big colorful things go boom wink.gif. It's ironic that the HE was so much more effective than the "antitank" rocket type at killing tanks.

Charles

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