After writing up our recent ode to Missile Boats, it got me thinking about missile technology in the BattleTech universe. Not how each missile seems to do about as much damage as a modern-day bottle rocket, or how it can fly just about as far before running out of gas. No, it made me think about just how many of these missiles you can stuff inside a ‘Mech.
Think about it: a single ton of LRM ammo is 120 missiles. That seems like a lot considering a modern jet fighter has trouble carrying 10 of the things. Even the somewhat modern M2 Bradley Infantry Fighting Vehicle doesn’t carry more than 7 missiles in its magazine, so where does a ‘Mech get enough room for 120?
To find out, I decided it was time to do some math. But before we could bust out the calculator, I’d have to pick a missile-toting ‘Mech to be our scientific guinea pig. I chose the Mad Dog for its distinctive silhouette, and because it’d be relatively easy to calculate the volume of those boxy missile racks it has for shoulders.
Now that we have our ‘Mech, it’s time to see how big those missile racks are. We know that a Mad Dog is roughly 12 meters tall, and those missile racks are about a third of its height, so we know they’re roughly 4 meters in height. Eyeballing the thickness I’d get about 1.5 meters wide, and roughly another 4 meters in depth. That gives us a total volume of about 24 m3.
But that missile rack isn’t a perfect cube; it’s got an angled side, and all these fiddly bits cut out, so I’d say we’ve only got a triangular prism to work with. That halves the volume we have available, so we’re down to 12 m3.
Not to worry – we still have plenty of space to work with. Each of these side torsos has 120 missiles, and if we assume each missile to take up an equal amount of space we know that they have to take up at maximum 0.1 m3 per missile.
Now that we know how much volume each missile can take up at a maximum, it’s relatively simple to calculate the possible dimensions of a single LRM. Since the height and width of a missile are the same (since it’s a cylinder, they’re both just going to be the diameter of the missile), the only question is how long the missile could be.
Let’s say the missile is 1 meter long (which is actually close to the length of a modern-day missile). The formula to work out the diameter of the missile would be:
0.1 m3 = L x W x H = 1 m x W x H = 1m x (W2) = 0.316 m
0.316 m is roughly 12.5 inches or a little over a foot in diameter. For a 1 meter long missile, a diameter of a foot is a bit chubby (maybe more closely approximating an artillery shell than a missile) but totally within the realm of possibility.
But we know that side torso isn’t just dedicated to missile ammo. There’s the LRM-20 launcher itself, a few crits of XL engine, and double heat sinks stuffed in there too. So let’s say that there’s really only half the available volume for missile ammo. The formula then changes to be:
0.05 m3 = L x W x H = 1 m x W x H = 1m x (W2) = 0.224 m
That still gives us a 1-meter long missile with a diameter of close to 9 inches. If we compare that to a modern-day missile, like, say, the AGM-114 Hellfire (which is 64 inches long and 7 inches in diameter), we’d see those numbers are roughly in the same ballpark and still very reasonably missile shaped. Cool.
Of course, we should also consider the fact that each missile isn’t a perfect rectangular prism, and each cylinder can save space by stacking in between the cylinder below it. My math wizardry is far from able to calculate how much space we’d save, but I’m sure one of you mathematicians could figure it out in the comments below.
So it seems a big ‘Mech like a Mad Dog doesn’t have any trouble carrying around 120 missiles, but what about a smaller missile ‘Mech? Let’s take a Javelin and see if it still can carry around a full complement of missiles like its heavier brethren.
Once again, we have to figure out how much of a vaguely man-shaped ‘Mech’s chest can be devoted to missile ammo. I don’t have an exact height for the Javelin, but since it’s a lighter ‘Mech I assumed it to be around 8 meters tall. Given that height, those boxes in the chest look to be around 1 meter wide and 1 meter high, and it has a 2-meter depth to its chest. Thus we get an available volume for missiles of 2 m3 for a single ton of SRM ammo, which is 90 missiles, and each missile can take up 0.0222 m3.
Since these are SRMs, let’s assume they’re going to be shorter than the long-range missiles and give them a length of half a meter. Using the same formula as before, we get a 0.21 m diameter missile or 8.26 inches. That’s still very reasonably missile shaped even on a tiny ‘Mech, and once again if we’d stacked those missiles properly we’d have even more volume available for an even bigger missile.
Before we all start celebrating this miracle of a single aspect of BattleTech that makes physical sense, there is a condition where a ‘Mech’s capacity for missile ammo starts to break down. When a chassis starts to horde ammunition, such as the Archer and its 4 tons of ammo, suddenly you go from hurling missiles to throwing shoe boxes that explode.
But hey, I’m happy to find out that my favorite ‘Mech designs can carry as many missiles as they say they can (unlike autocannons, which still make no sense).
And as always, Mechwarriors: Stay Syrupy.