Post by Topaz on Jun 28, 2006 14:46:02 GMT
mctoddridesagain said:
I doubt the canisters would need much propellant anyway (if we assume them to use explosive propellant, rather than pneumatics). They are launched/fired at low velocity - I'm sure there's a quote describing one such canister as tumbling end over end through the air which implies this, as well as the fact that they don't seem to fire them to a great range - perhaps a mile or so. Being fired at low velocity, the canisters only need quite thin (thus light) walls (also consistent with being able to smash upon landing), so most of the payload is the Black Smoke generator (whether a liquid or solid or whatever). Now, because I'm at work, I don't have the figures to hand, but a late 19th century naval gun that could fire an 800lb shell ten miles used something like a hundred or so pounds of propellant (such as cordite). This is clearly a much higher performance gun than the Black Smoke 'cannon', so one might assume each canister may only use the Martian equivalent of a few pounds (or a few tens of pounds at most) of Martian propellant (assuming it to be as powerful as, say, cordite). Such a quantity will take up a very small space. Something like Topaz's multiple canister/propellant combo is entirely reasonable - the propellant, packed into the base of the canister rather like the propellant of an infantry mortar, will occupy a tiny fraction of the volume of the canister.Yeah, you're right - the description in the book does imply a very low-velocity round. The tumbling is definitely described in the book.
I like the mortar-round analogy. The round becomes completely self-contained and there's nothing left to 'eject' like a conventional bullet casing. All they'd have to do to reload is slide more rounds down into the barrel. It would be a simple matter to have the boosting charge ignited electrically, with connections that hook up automatically by their position in the barrel. Nice setup for a combat reload, or as is more implied in the book, launch tubes could be reloaded back at the pits and simply delivered 'ready to fire' to the FMs involved in the fighting as needed. Another FM could do the transport duty, carrying several launch tubes and self-defending with the Heat Ray.
I believe the book mentions that one martian fired as many as ten rounds in one firing session (someone should probably check me on this point), so that can put the upper bound on the requirement. Not unreasonable to have that many rounds superimposed in one launch tube, I would think.
Nice.