Magical Airships

[Mysterious Dark Lord v3.2]

For many years, I've been doodling on-and-off with a technomagical world concept. I inevitably get around to airships because - as everyone knows - airships are just a bit below lightsabers on the Kewl Skale.

But I also try to make the numbers work. And I canNOT get the basics of economics out of my head. And I try to make things logical.

So the objective is a reasonable and economical airship with a cargo capacity of 100 tons. This is comparable to some vessels of the Age of Sail and would have both civilian and military applications (even without gunpowder). I recall from an economics study I read once that the average Age of Sail vessel was about 50% cargo, so we'll assume the rest of the ship is another 100 tons, for a total of 200 tons (actual weights of structures can wait - this is just a theoretical study).

For propulsion, use a mage who knows the "Wind" spell. Sails could be added, but would not be necessary if the wind was controlled.

Cast "Levitation" spells on a boat ... The standard approach to magical airships has difficulties. How do you land it without a drydock or a body of water? And the standard Levitation spell requires 5600 energy per ton of cargo. (BTW, GURPS Magic 4e doesn't list the cost of a permanent Levitation spell, just the item. I had to go to my Vehicles book to get it.) So 200 tons lift would require 1.12 million energy. NOT economical.

So we go to the GURPS Books and look at spells.

"Flying Carpet" Spell ... Sounds ideal. It even provides propulsion and stability and could be cast on a huge carpet, eliminating the need to look at anything but cargo capacity. At 200 energy per 25 pounds for a permanent spell, that makes 100 tons work at ... 1.6 million energy. Worse than Levitation. Not to mention the practical difficulties of a cargo vessel made of burlap or some such material, especially for warships. And making it out of sturdier materials increases the weight and therefore the energy. NOT economical or practical.

"Create Air" Variant Spell to fill a balloon with hydrogen or helium ... Lessee ... for 200 tons lift, one needs approximately 6 million cf of helium. A single ordinary casting of the Create Air spell creates 225 cf of gas for 1 energy. So enough gas to fill the balloon would cost 80,000 energy. A "Create Air" wand with four points of Power would be only 4200 energy, creating 900 cf of helium per casting for no energy, thus allowing the balloon to be constantly refilled. Now the only difficulties are the standard ones for airships. Very attractive.

But while looking through the spells, another option occurred to me...

Use a permanent version of the "Atmosphere Dome" spell ... The "Atmosphere Dome" spell allows the caster to decide on the composition and pressure of the gasses inside the dome, selectively keeping out (or in) the ones he wants. So cast the spell to keep out the standard atmosphere and set the internal pressure to zero. Result - a Vacuum Balloon, with even better lift than hydrogen!

There is no permanent version of "Atmosphere Dome" listed, but other "Dome" spells can be made permanent for 100 times their casting cost. Vacuum has 1 pound lift per 13.6 cf, so 200 tons lift would be approximately 5.5 million cf of vacuum. For a dome 12 feet high (the standard height), the radius would have to be about 41 yards. For a permanent casting, this would be 16,400 energy. Economical, yes ... but how does it compare to an actual balloon?

For one thing - no balloon. The spell can be cast on a platform over the deck of the airship (or the deck itself - there's no reason to let people walk on top of a flying ship). Thus, the balloon ripping is not a hazard. Maintenance is reduced since the huge fabric of the balloon doesn't need patching or inspecting if it's just an energy field.

The Magic text is unclear on whether or not a permanent Area spell could be controlled to shrink or grow the area it contained. But if it isn't, a variant spell could be researched with "Atmosphere Dome" as a prerequisite. Thus, the buoyancy of the airship could be raised or lowered by simply altering the size of the Vacuum Balloon, allowing the ship to land and take off at will.

So there are two practical and economic ways of creating a magical airship with large cargo capacity - magical artifacts for creating lifting gas; and creating a magical vacuum-filled force field. And both are cheap enough to consider having fleets of airships that could land anywhere.

Any commentary?

[garfield]

Originally Posted by Mysterious Dark Lord v3.2

Any commentary?

Get the comparison with real ships out of your head. Transport through Air does not make sense, unless speed or other strategic factors are of importance.

Try to think of a much smaller scale: a flying oxcart would be definitely enough for most purposes. You don't need to fly iron ore around ...

[LoneWolf23k]

I think Flying Ships warrant the creation of a new spell.. An Enchantment college spell, with Magery 3, Hawk Flight and Magic Carpet as prerequisites.

[StevenH]

I have some notes on these kinds of things on my website, in the "Gith Nebula" section, based loosely off of the ones in Shannara. The magitech and environment is different from yours, but some of the stuff there may be helpful.

Garfield has a point about not comparing them to actual water ships. They will be completely different in design (at least eventually, if they become common). They will also develop landing facilities to accommodate them, and the economy will also adjust (it will probably resemble a more modern economy with easy transportation than a medieval one).

I also have a few created with Vehicles, which I can post later as examples (if you want; they probably won't be too useful as the magitech is very different).

Edit: according to 3e Vehicles, there is a note on the Elixir of Icarus, that can make a vehicle capable of flight. Suggested time and cost is $1000 in materials, one week of time; number of doses equals body armor factor/100. Also there is an "obscure variant of the Levitation spell"; energy is 1 per 2 lbs. of vehicle max load, with a minimum of 1000 cost.

[Mysterious Dark Lord v3.2]

Originally Posted by garfield

Get the comparison with real ships out of your head. Transport through Air does not make sense, unless speed or other strategic factors are of importance.

Try to think of a much smaller scale: a flying oxcart would be definitely enough for most purposes. You don't need to fly iron ore around ...

Rowboats are enough for most purposes, too, but large ships were still built. And yes, speed is one of those factors.

Mobility is also a factor. Plateaus, distant jungles, and the far side of impassible deserts are all inaccessible without prolonged expeditions. But a flying vessel of large capacity makes trade possible, which makes large-scale civilization possible.

And the military applications are obvious, including the ability to put entire batallions or huge numbers of knights far behind enemy lines, breaking sieges, simply dropping weighted arrows on enemy troops, and transporting huge amounts of supplies to where they need to be with minimum risk.

Besides which, as I mentioned, Airships are KEWL!

Originally Posted by lonewolf23k

I think Flying Ships warrant the creation of a new spell.. An Enchantment college spell, with Magery 3, Hawk Flight and Magic Carpet as prerequisites.

Economics are also a factor. People with Magery 3 are scarce and expensive. The options I outlined could be done by people with Magery 0 or even by non-mages in a high-mana zone. Much cheaper.

Besides, if the Wind spell is used for propulsion (only four prerequisites, none requiring Magery), then Wind Controller can be a low-cost occupational template for airshipmen with Magery 0.

[Mysterious Dark Lord v3.2]

Originally Posted by StevenH

Garfield has a point about not comparing them to actual water ships. They will be completely different in design (at least eventually, if they become common). They will also develop landing facilities to accommodate them, and the economy will also adjust (it will probably resemble a more modern economy with easy transportation than a medieval one).

That was a reference to the standard or default approach to flying ships in fantasy, which is to make them as identical to boats as possible (a way of thinking that has bled into science-fiction, making space into an ocean). Personally, I would think that magical airships would resemble longhouses.

And I expect the economy to be different. Medieval economics are scary.

Originally Posted by StevenH

Edit: according to 3e Vehicles, there is a note on the Elixir of Icarus, that can make a vehicle capable of flight. Suggested time and cost is $1000 in materials, one week of time; number of doses equals body armor factor/100. Also there is an "obscure variant of the Levitation spell"; energy is 1 per 2 lbs. of vehicle max load, with a minimum of 1000 cost.

I tried to use the 4e GURPS rules (including Magic) in my assessments. If I were making a magic airship with 3e Vehicles, I'd use the alchemical route (alchemy lends itself more toward a industrial/technomagical civilization).

[Anaraxes]

Transport through Air does not make sense

The 747-400 freighter carries about 113,000 kg with a range of 8200 km; 774 m^3 or about 60 Traveller ship "tons" (dtons). The 747-8 variant carries even more. According to Boeing, as of 2005 there were over 250 747 air freighters in service, carrying half the air freight in the world. Around 20-30% of the US-China trade is air freight. Seems to make sense to a lot of people.

An airship isn't going to consume as much kerosene as a jet. And if you're willing to travel slowly -- like an ocean-going ship -- you need even less power. The zeppelins might well be more like ocean transport than air transport in terms of overall economics.

Both airship and watership are supported by bouyancy. Waterships displace more weight per unit volume, so they can be smaller for heavy cargo, or conversely, carry more at the same size. On the other hand, given magic to support the airship, weight may be irrelevant.

"Permanent" magic items are traditionally often that, durable beyond reason. The cost of the Vacuum Dome would be amortized over the life of the ship, maybe the life of several ships built around it.

Operating costs for the airship might well be lower. It'll be cheaper to push air out of your way than water when moving; it's less dense. Maintenance, hm. Salt water is notoriously hard on just about everything. It might take less work to maintain the airship; no need for all those swabbies constantly chipping and repainting everything. Of course, if you get to make Vacuum Domes to support airships, you could make Weather Dome hulls for ships that never need maintenance, either. (Please name the company that manufactures these magic hulls "General Products"...)

[tshiggins]

It looks as if you thought this through, very well.

The crew would have to beware air pirates with Dispel Magic. Could get messy.

Would the concussion from the collapse of the vacuum dome destroy the ship, or would it actually have to smash into the ground?

[Dalillama]

Originally Posted by garfield

Transport through Air does not make sense, unless speed or other strategic factors are of importance.

Why on earth not? Overland transport before railroads is massively slow and expensive; that's why ships and barges were the primary movers of bulk goods in the premodern era, and almost every major trading town was a seaport or on a river.

Try to think of a much smaller scale: a flying oxcart would be definitely enough for most purposes. You don't need to fly iron ore around ...

Why on earth not, once again? If you have lots of iron ore near the mines, but you need it near the capital, you'll get it there faster in an unpowered airship than you would by oxcart, and you won't need to feed your draft animals on the way. If you have a power source (Wind spell, propellers, whatever), that's even more true. Your armies would have an unbeatable logistical advantage, as you could supply them in any sort of terrain without any delay.

Originally Posted by Anaraxes

"Permanent" magic items are traditionally often that, durable beyond reason. The cost of the Vacuum Dome would be amortized over the life of the ship, maybe the life of several ships built around it.

I now have the image of clans of wind mage nomads/gypsies, who travel around in airships passed down through the generations, serving as traders and messengers.

[Anaraxes]

beware air pirates with Dispel Magic

The thought had crossed my mind. Actual pirates probably aren't too keen on destroying the ship and having their loot plummet out of reach. But it's certainly a concern for warships. Might be interesting to sketch out some rules and see if it's more efficient to blow away the superstructure and crew with fireballs or just keep Dispelling until the ship crashes.

It's the all-or-nothing aspect of the Dispel that's so concerning. A warship would probably have many small Domes rather than one big one for survival, and probabl some extra ones that can be quickly expanded to replace lost bouyancy. How about nesting several of them in concentric Domes, so that you have to Dispel it several times, pop-pop-pop, before anything bad happens?

Or to take that thought in a slightly different direction, the big areas are expensive. What happens if rather than an entire concentric dome, I make little walls to absorb the Dispells? The dome takes the same hits from any direction. A series of walls makes direction matter. Repeated hits wear down the supply of walls, and you'd like to focus on just one point to batter through when possible. In short, this is the magical equivalent of Star Trek/Star Fleet Battles-style shields. So you can have the same dramatic sequence of wearing down the ship. This setup might also encourage closing and boarding, so you can cast Dispel as a Regular spell and target the important dome, rather than the ranged Dispel Missile, and avoiding having the directionality and targeting problems of the long-range combat.

wind mage nomads/gypsies, who travel around in airships passed down through the generations

Nice. Maybe the Vacuum Dome is a clan secret. Or perhaps it fits with "Mysteries of the Trade" for shipbuilders.