Dust Explosion - Grain, flour, wheat

[LokRobster]

In the environment of Magic, it seems a simple matter to create a new spell that introduces the precise mix of air pressure, oxygen percentage, and flour dust volume and enables the entire mix to "magically" take on the properties that the occasional grain silo stumbles on accidentally. Perhaps utilizing the Air College and a minor matter manipulation?

Gadgeteering a new spell might be an adventure...

[mr beer]

What about shrapnel? It sounds like a 'big burn' is much more likely than a 'big boom' but if there is a proper explosion, all the sharp pointy things flying around should make for fun secondary damage to the attackers.

[Anaraxes]

Originally Posted by mr beer

It sounds like a 'big burn' is much more likely than a 'big boom'

Not that "big burn" isn't likely sufficient, given that the enemy troops are going to be inside the flour cloud. You don't really need a wave of overpressure to kill them.

[mr beer]

Originally Posted by Anaraxes

Not that "big burn" isn't likely sufficient, given that the enemy troops are going to be inside the flour cloud. You don't really need a wave of overpressure to kill them.

Yes, agreed, just thinking it would be fun to have an increased kill radius with flying bits of mail, spears, enemy soldiers etc. creating additional casualties.

[Nereidalbel]

The sudden increase in air temperature from the FWOOSH will definitely produce some sort of shockwave. Nowhere near as intense as TNT, but, still noticable.

[Donny Brook]

Originally Posted by Icelander

There's a lot of arrows, crossbow bolts, darts, javelins and scorpion bolts.

What about using pebbles and fly higher?

[acrosome]

Originally Posted by Nereidalbel

They have less than a day of prep time, so, they have to use what's on hand.

Can Earth to Stone make Phosphorus? Is there a canonical way to make petroleum?

[Icelander]

Originally Posted by acrosome

Can Earth to Stone make Phosphorus? Is there a canonical way to make petroleum?

In both cases, the PC has no access to such magic. In setting, magically creating stuff or even just magically processing stuff into other stuff, tends to demand either a very specific spell that has been worked out by generations of mages beforehand to accomplish a single transformation even when the mage using it may not have a perfect grasp of the physics behind it, e.g. Polymorph spells that change people into animals, or a more versatile spell effect combined with enough scientific knowledge to use the spell as a magical tool for the manufacturing process.

In other words, there are spells which would allow a mage to process crude oil into petroleum, but only if he understands the process well enough to use magic as a tool instead of the physical tools used in our world. The PC mage actually has a lot of the traits he'd need to do that, but not all of them, and he's not going to be learning a new magico-industrial process that very day and then using it fast enough to make a couple of tons of petroleum.

And, in any case, crude oil is not available to him in sufficient amounts for this to be viable. He knows about significant natural reserves of oil, which is used to make the local equivalent to Greek fire, but these reserves are located a few hundred miles away.

As for transforming ordinary dirt or stone into permanent magically-created phosporous, that's so expensive in terms of magical power that even if the character had learned a spell for it, he'd only get a few ounces if he directed all of his magical power for the day into it. A more practical way would be to use Alchemy and the appropriate reagents, but the amount that could be created in some 8-12 hours would still be ludicrously small given the size of the battlefield and the enemy army.

[Icelander]

Originally Posted by Donny Brook

What about using pebbles and fly higher?

I doubt that the terminal velocity of a pebble is significantly higher than that for a heavy crossbow bolt falling point first and the crossbow bolt is both heavier and sharper. When I think 'pebble', I imagine something no heavier than an ounce, maybe lighter. So pebbles would be a lot less effective as weapons than bolts.

You could, of course, probably carry much more of them, as there is no need to drop them in a specific way that ensures that they fall point-first. But how much damage would a pebble at Move 70 (or even Move 100+) do against a hoplite in a DR 6+ helmet and with both shoulder and upper torso armour of DR 5+?

I don't really know how high you'd need to go to get terminal velocity from a pebble or a bolt. I imagine that at a 1,000 yards, you are likely close enough to it so that going higher is probably not worth it, but I haven't actually modelled the physical dimensions of the objects and calculated air resistance.

Rocks of four ounces or so are more promising as weapons, of course. But as long as you have heavy crossbow bolts weighing four ounces, why not use those instead? If they hit point-on, they should penetrate armour much better than a round stone of the same weight and the after-armour effects are most likely more dramatic.

The drawback to dropping pebbles, rocks, bolts, arrows or javelins, however, is that from a height of 1,000 yards, the odds are that most of the weapons do not hit anything. With Dropping skill 8-12, I think it's easy for the flying mages to miss columns of enemy troops entirely. And even if they hit, most of the weapons will hit the spaces between men.

Sure, there will be casualties. Have been, as the PC did make a sortie dropping bolts on the vanguard of the enemy army as they approached the city walls. But he was dissatisfied by the effects and wanted to explore if anything in the city would have more impact for the same payload weight.

[Icelander]

Originally Posted by acrosome

I apologize- I only read about half the thread. But, if you're mages can haul "a ton or two" into the sky is there a reason you're not using a ton or two of low-TL napalm? Which would then be handily ignited by your fireballs?

Originally Posted by Nereidalbel

They have less than a day of prep time, so, they have to use what's on hand.

Several tons of Thayan Fire* and the even more volatile self-igniting Alchemist's Fire** is what the PC's side have been using to win several key naval engagements and to take two important ports from the enemy. The reason the PC is trying to improvise a burning weapon from found supplies is that they are running out of their ordnance and will not have time to ship in more fantastic flame weaponry before their newly acquired port city is assaulted by the field army that was encamped outside it.

Obviously, purpose-made TL3^ and TL3+1^ alchemical flame weapons are superior to improvised solutions. For one thing, they work reliably and are fairly simple to deploy. They can also be used without having to carry off a perfectly timed fiendishly complex plan that depends on every part being executed flawlessly in order to have any chance of working. And the purpose-built alchemical ordance does not require one to expend irreplacable assets like fantastically expensive magical scrolls that allow a one-time summoning of a spirit of the air that merely might be able to create conditions that allow flour to become a weapon.

*The setting name for the equivalent of Greek Fire.
**Not unlike G.R.R. Martin's wildfire.