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Thamir
2008-02-15, 03:47 AM
I am designing a dnd campaign setting based on Dark Sun, Eberron, Call of Cthulhu and The Edge Chronicles, and I need some sort of engine or magical effect that would keep an airship up in the air. I already DM and Eberron campaign and therefore I am not crazy about bound elementals, but something to do with elementals is fine. So try and think up the most original airship engine possible. It doesn't matter whether it is steam-punk or Roman, as long as it isn't a jet engine you're fine, but maybe no propellers. Get to work!

Corinthus
2008-02-15, 03:57 AM
In my campaign, i use 'Tenser-ships'. Its basically a large magical bubble akin to 'Tenser's Floating Disk', except you can hang a ship from it. Throw some glowing magical do-dads in, and they even move where you want them to.

Storm Bringer
2008-02-15, 04:47 AM
other 'lift' tricks:

A heavily modifed version of levitate, reverse gravity or fly. don't go into details about it, just say it's a scaled up version of the spell.

From the arms and equipment guide, using a sky-whale as the lifting body and building on and under that. yes, a flying whale. maybe as a flavor thing for a more primitive culture?

borrowing form Space: 1889 (which, by the way, is made of win), liftwood, a naturally occuring wood that exhibits anit-gravity affects. grows only in certian areas of the world, with stiff competion for the stuff.

movement
...

I was about half-way though writing a jet enigne equivlent using a potral to the elemental plane of fire when i saw the 'no jet engines' bit. Damm.

well, barring that, I'd settle for good old sails. Maybe with a magically enhanced wind for proplusion, maybe not.

or maybe another heavily modifed reverse gravity spell, that lets the ship 'fall' in the direction desired.

or just pulled charriot style by a bound air elemental. cool but slow.

other ideas for this airship:

souped up Immoveable Rods as anchors.

maybe set up another modified reverse grav to run the plane of gravity though the ship, a la spelljammer? this would let you use the outside of the lower hull without worrying about falling off. plus, it's cool to walk on ceiling.

Xefas
2008-02-15, 05:14 AM
A traveler of the planes wanders about seeking his fortune when he happens upon a Kython infestation. Careful to maintain his anti-detection spells, he lives among them and studies their properties. Sensing a gold mine, he snatches up a bunch of unborn Kython eggs and makes off with them to an undisclosed location. Over many generations, he pokes and prods the evolutionary traits of the Kython fetuses until they assume an incredibly simplistic yet effective form.

Its essentially a big pulsating blob of flesh with two orifices. One is a mouth. You throw organic material into the mouth, the "engine" breaks it down, and sense its form is very basic and efficient, it uses a minimal amount of the energy extracted for digestion and converts the rest of it into kinetic energy which it then ejects out of its other orifice.

Point that orifice in the opposite direction you want to go and *bam* you have a Living Engine. Not to mention the fuel is cheap. After you go genocide some kobolds, just heap all the battered and broken bleedy bits into the engine and away you go.

Were-Sandwich
2008-02-15, 05:18 AM
You could steal one of Terry Brooks' few good ideas and have them collect solar energy through the sails and channel it through special crystals to provide thrust.

Or go old school and use Cavoralite (sp?).

What about using Repel Metal and Stone? Put a thick metal layer around the ship, and use a custom magic item of continuous Repel Metal and Stone mounted on a tripod aparatus so you can direct the point where the repelling is coming from. You'd have a very maneuverable ship, to be sure.

theMycon
2008-02-15, 05:51 AM
The engine is not so important. The airship body is. This post will include a lot of vague math & physics, and the last two paragraphs will tell you the functional part. And throwing a light engine on either (especially the smaller one) will make them failsafe unless the flyer's damaged.

First, brief fundamental fluid dynamics and other relevant physics- the shape of the wings is paramount. I'll presume you've all heard of "the bernouli effect"- that, since fast-flowing fluids (air included, if you're going fast enough) produc less pressure than slow-moving, if you make the bottom flat & the top rounded, it'll produce lift. While this is technically true, it'll never lift anything much heavier than the wings. I've had a professor (mostly through bad math, like the "bumblebees can't fly" trope) "prove" that the lift it produces inevitably will exactly counter the weight of the wings at any speed above a certain threshold. This is a lie (if you can follow his math, the errors will give you a headache), but a useful one.

The lift is actually produced by the "angle of attack"- or the angle of the wings, relative to the plane. A brief example- next time you're driving, put your arm out the window, hands flat. It'll push a little back. Then angle your arm so the front's up. The wind follows it down, and (equal & opposite reaction) pushes your arm up. Also, it pushes back more since more air pushing back is stopped- this will slow you down, so less wind pushes, so less pushes you up. The rounded wing tops (Bernouli) doesn't do this, so it'll keep you up, but it won't get you up. Given arcane geometries (much more fun, and I could actually explain it with a whiteboard to draw on) or some vector analysis (takes about 10% as long to calculate), you can find a best angle where it'll provide the best lift for your suspected payload and wing size.

If you can't move the wings and have a good engine, call it pi/8 (or, with my fat hands, the top of my pinky's just below the bottom of my thumb). If you can move the wings, have a bigger angle to get going and a much shallower one during the flight. If your engine sucks, rely on the Bernouli effect and start high.

Finally, you want the vessel as light as possible. You're obviously fighting gravity the whole way. You might want to make a rigid, strong body, but unless you have enough adamantine to shape the whole body, and a skilled enough worker to make it wafer-thin, you're best with an extremely small body (so it won't hit much resistance) or a flexible body (so it'll ignore bludgeoning damage). Large dirigibles traditionally have a light "skeleton" just inside the balloon body, though I forget exactly why (I have hypothesis that make a little, but not much sense).

[more stuff in morning. I'm getting tired. Feel free to nitpick so I can explain. If you tell me what aspects I'm missing, please do- I know the physics to solve it all, but forget the problems.]


So... if you want a low-load (say two passengers, or up to about 300lbs), you just need long wings angled very slightly up with the "flat bottom, egg-like top" shape, some chains/ropes to turn it, a high starting point, and to be going up against a lot of wind- stronger wind pushing against you is actually better with a clever pilot- it'll slow you but push you up, and you can make it speed you up in another direction. Then, bank the ship and lean a bit, and you can make yourself accelerate back where you wanted. Keep in mind, you want to be going as fast as plausible in some direction first, then aim towards your goal second. Unless theweather's on your side, this can only work so long, but if this crashes, and you didn't crit-fail for twenty minutes straight, the pilot was trying to crash it.

If you want a big ship, you need a massive, blimplike body, some cold magic/gas bleed valve to make it sink, and some fire magic/condensed gas to make it rise. The gas-bleed valve can be used to maneuver, or a rudder to turn by "slowing" in one direction, and just have some constant force pushing you "forward" to keep you going. This'll sink like a stone if the gas chamber's pierced, but you can make multiple chambers to make it more durable.

JeminiZero
2008-02-15, 05:56 AM
A blimp maybe?

Take water, stick 2 rods of metal inside, and have a caster with the stormbolt reserve feat channel lightning continuously through the rods. Collect the gas produced and voila.

Belkarseviltwin
2008-02-15, 05:58 AM
Decanters of Endless Water?

pinkbunny
2008-02-15, 06:01 AM
Jemini, that is a horrid idea, not only are you making hydrogen gas, you are making oxygenated hydrogen gas.

Were-Sandwich
2008-02-15, 06:07 AM
Yeah. First smart caster who uses fireball, it goes up like the Hindenburg (sp?). Nice abuse of Storm Bolt though.

Triaxx
2008-02-15, 06:07 AM
*snort* Terry Brooks had several good ideas. Though I admit he repeats himself.

Anyway...

For levitation, my world uses a crystal that naturally floats in the air, can be grown, and harvested. It's ripe when it floats up into the air. The actual height of levitation, is controlled by channelling magic through it. It can also do propulsion by the same method. Naturally a Sorceror pilot makes this easier, but any magic does the trick, even wands.

For propulsion, the crystals work, or sails. On the other hand:

Most ships of the world have decks where the outer edges are studded with crystals or gems, all of which have been carved to refract and direct light. This light is focused through a network of pipes all sliding through decks and walls into the engine room, where they project a focused light and heat onto a water tank, heating the water to generate steam, which in turn powers two turbines mounted in the very bottom of the ship. These turbines are capable of drawing air, or water, providing propulsion whether you fly or float.

Note: These ships were designed for a world of very high ambient magical energy, where some creatures breath magic, rather than air. So you would have to generate your own movement rules.

Thamir
2008-02-15, 06:14 AM
I was about half-way though writing a jet enigne equivlent using a potral to the elemental plane of fire when i saw the 'no jet engines' bit. Damm.

No No by all means do it! It was my way of saying no current technology. If it is magical, not scientific please do it! It sounds great!

Oh and I belive you would need a Decanter of Endless Diet Coke and Summon Mentos III.

MorkaisChosen
2008-02-15, 06:25 AM
A combination of something the Ancient Greeks had, a mechanism and a touch of magic:

It's very simple to make a Spinny Thing- just a globe with water in it and fire underneath, with two pipes coming out at an angle. Water boils, steam makes it spin. Link it to some gears and make a propeller or something, and for the fire? Maybe a fire elemental or the fire reserve feat (if that works).

JeminiZero
2008-02-15, 06:34 AM
Jemini, that is a horrid idea, not only are you making hydrogen gas, you are making oxygenated hydrogen gas.

Well obviously, you have to seprate the gas collected from each rod.

I just had another Idea. You basically take a permanent force sphere (infinitely hard, completely air tight), and then pump air out of it (maybe by teleporting it out or something). The resulting sphere will be lighter than air, yet virtually indestructable.

MorkaisChosen
2008-02-15, 06:35 AM
Actually, the two gases produced make the most efficient fuel possible- they're in proportion for complete combustion.

Storm Bringer
2008-02-15, 07:14 AM
No No by all means do it! It was my way of saying no current technology. If it is magical, not scientific please do it! It sounds great!

Oh and I belive you would need a Decanter of Endless Diet Coke and Summon Mentos III.

ok. I like the coke/mentos idea though.....

It's simple, really: place a magicaly substained fire (not inheritaly an element, maybe just a portal to the plane of fire) of variable intensitity inside a open ended tubular housing (i.e. a jet engine case) with some method of force-feeding air into it. to generate thurst, you turn the fire up to really, really hot. The air around it is heated by said really hot fire, and expands. since air is being forced in one end, it expands out the back, generating thrust.

This is pretty much exactly how a jet engine IRL works, with the fuel scource changed. While in thoery you could use this trick to build a ship capable of beating any modern jet in speed, I'm assuming you are not after that fast a craft. the simplest way to keep speeds down to a reasonable level is to limit the ability of the engine to draw in fresh air. Modern jets need to use huge fans and such to get enough air in work, though they also have to deal with lower atomdspheric pressure at high altiude. if we said the magic that draws the air in is only able to draw so much, you've got a effective way to keep speeds down to whatever is suitable for the setting (Say, 100mph absolute max, with 30-50mph being the norm).

Hunter Noventa
2008-02-15, 08:40 AM
One game I was in had an airship that hovered by means of immovable rods, and moved by means of flapping enormous wings driven by what was essentially an internal combustion engine driven by three specially cast Mage Hands that somehow moved like a piston because there were two charged one way, with one inthe middle charged the other way, like magnets.

The net result was that there as a variable anti-magic field in the engine room that could be adjusted from the bridge, and that controlled how fast the hands moved and how fast the ship moved in turn.

Ninjalitude
2008-02-15, 09:13 AM
Point that orifice in the opposite direction you want to go and *bam* you have a Living Engine. Not to mention the fuel is cheap. After you go genocide some kobolds, just heap all the battered and broken bleedy bits into the engine and away you go.

You sir have a sick, sick, mind..... could I please have your autograph?:smallbiggrin:

I think that if you set up a turntable mounted some Immovable Rods on it and had some sort of bound air elemental to turn it, and a way to turn off / turn on certain ones in a certain order (having different command words for each one?) and saying them in a certain pattern you could have only the ones on the bottom work but the wheel would still be spinning and once the activated one was at the end on the turntable say its command word and shut it off. Imagine a boat with 2 armored wheel contraptions and the helmsman yelling out different patterns of command words to move it up or down.

SpikeFightwicky
2008-02-15, 09:40 AM
Two ideas (both similar - both far fetched :smallconfused: ):

1) The engine is a device engineered to open a semi-permanent gate to Pandemonium, and transmutes the maddening, howling winds that waft through the gate into energy that generates lift and propulsion (possibly through a ship-wide mesh or skeleton constructed of a special material to take advantage of the energy). Possible extras for flavour:

- The engine device must be 'fed' cold iron chunks semi-regularly or the gate will collapse and the ship will plummet. The engine workers are a special race that are resistant to the maddening effect the howling wind of the engine room would have on a regular individual (or possibly a race of broken or insane individuals that are already a tad insane).
- The engine can operate for 24 hours continously at 2 miles an hour (48 miles per day). It's possible to push the engine to achieve faster speeds, but each hour of exertion has a cumulative chance of damaging the engine (which can have a variety of consequences, including monsters from Pandemonium manifesting in the engine room through the gate, or at worse having the gate expand and drag the entire ship into the plane of madness).

2) The engine is a strange device that makes anything it touches levitate. It looks like a perfect black sphere, similar to a sphere of annihilation. As the sphere touches the hull of the ship, it causes it to lift as though levitating. Once it's in the air, sails can then pick up winds and send the ship on its way (in case of emergency, a device on the ship's deck can be used by an arcane spellcaster to channel spells into a 'gust of wind' like ability to push the ship if there are no winds. The equivalent of a 4th level spell will power the device for an hour (4 1st level spells, 2 2nd level spells, 1 3rd level and 1 first level spell, etc...). The wind lasts for an hour and moves the ship at 2 miles an hour (spending twice the required spell energy - 8 levels of spells - will increase speed to 3 miles per hour). An arcane caster can also control the engine sphere itself. The more the sphere is sunk into the hull, the higher the ship will fly. It can be controlled like a sphere of annihilation, but with no consquences for failure, and it can only be moved up and down.
The reality of the engine:
- The sphere is actually a conduit to the Far Realms (in D&D cosmology), or the lair of an outer god (in Cthulhu 'cosmology'). Wizards wanting to create flying ships eventually devised a way to tap into the power from beyond and use it to generate a permanent levitation device.
- The engine's controller must be under the effects of a mind blank or be driven mad by the corrupting influence of the sphere. Anyone not shielded that enters the engine room must make constant will saves to avoid taking Wisdom drain from the strange energies emanating from the globe.
- If the sphere remains in contact with the ship's for longer than a week, there is a cumulative chance every hour that some being in the Far Realm will start to take notice. Anything can happen, from a maddening psychic scream echoing through the ship, to horrid pseudo-natural creatures emerging from the engine device. After 24 hours of 'rest', the engine can be put to work for another week.
- If anyone touches the sphere, their limb sinks into it. When they withdraw it, it's covered in a dark, greasy substance. Whenever a living being touches the orb, there is a chance that something on the other side will notice (treat as though the orb was used longer than a week straight).

Mad Wizard
2008-02-15, 09:58 AM
Large dirigibles traditionally have a light "skeleton" just inside the balloon body, though I forget exactly why (I have hypothesis that make a little, but not much sense).


I seem to remember hearing somewhere (Mythbusters maybe) that they don't actually inflate balloons enough for them to keep their shape, and that the skeleton does that.

sikyon
2008-02-15, 09:58 AM
Lots of Gust of Wind items to keep you aloft and moving. It's very simple, really. Just make big wings with sails on the angled horizontally, with permancied gust of wind items beneath them. Should work fine. Enough items/big enough sails.

Reverse gravity trap. put a few extremly dense objects in range of the trap and let it drag you upwards. Osmium/Irridium, anyone? Level 20 Reverse gravity will net you a 100 cube ft of osmium per trap going off which will lift 64 metric tons. Reverse Gravity has a duratino of 20 rounds at level 20 which will mean you can lift 20*64 metric tons, or about 1280 tons, enough to lift most oldschool ships. Though to lift the largest Manila Galleons you'd need a CL 24 trap.

Orak
2008-02-15, 10:36 AM
I had the thought of a large flying blimp like animal that is domesticated and trained as a pack animal. Instead of having a saddle ontop have a blimp-like setup like JemimiZero suggested.

I seem to remember stats for a creature in 2nd ed spelljammer. Just looked it up and it is practical planetology. Creature is a Holbag. Might want to scale it down a little cause the description gives it a size of several miles in diameter. Of course this could be a high altitude version and the immature ones are the ones that are used as blimps. The Holbags also have a lightning attack that they employ in self defence.

Also there is their predators, the Scavvers. These are basically flying sharks. They vary in size (I would just use shark stats for them) from the regular sized ones to the Air Scavvers which top out at 100 ft long. Perhaps a dire shark would be a suitable substitute for stats.

Just a few ideas.

BRC
2008-02-15, 10:40 AM
Such a whale exists, it's in the Arms and Equipment Guide

Storm Bringer
2008-02-15, 10:44 AM
Such a whale exists, it's in the Arms and Equipment Guide

Indeed, I mentioned it earlier.

TranquilRage
2008-02-15, 10:47 AM
I don't like the idea of using Force bubbles to create indestructible balloons, using that logic you wouldn't ever need another building material, ever.

Idea 1: SpellJammer chairs would seem to be the easiest idea. Just strap one to a vessel and off it goes. The more complex the throne and the more powerful the wizard the larger the ship it can lift. Navies are limited in size and power by the Wizards they can produce and the Thrones they can craft.

Idea 2: Improved Immovable Rods strapped to a pair of giant wheels, as the rods pass a pair of contacts magical energy is channelled into them that turns them on and off again. This way only one rod is active at any one time. By adjusting the placement of the contacts from a position vertical to hub of the wheel to a position in the direction of turn or against it the turning of the wheel would cause anything attached to it to rise or lower as it stepped its way through the air. The angle between the contacts and the vertical determines pitch and the rotational speed of the wheels determines speed.
A Failsafe mechanism could be rigged so that if a small ball got raised off its plinth (as it would in the event of a sudden fall) all the Rods become active along with some emergency ones along the hull.
Hanging the ship by springs from the axle of the wheels would smooth the ride out considerably. Suited more to Societies with lots of industry.

Subotei
2008-02-15, 10:51 AM
"The engine is magical. If you damage it, it will explode. You do not have the power to replicate such an engine."

Thats all the players need to know. Then watch their attempts to make some kind of weapon from one.

Meat Shield
2008-02-15, 11:12 AM
In the Tears of Blood campaign world (homebrew world being created on this forum) the gnomes have airships that you could also look for ideas for.

One of my ideas, however, was that they work much like the Nebuchadnezzar in the Matrix. Where those glowing disks were would be supercharged Tensers Floating Disks, essentially giving each ship weightlessness. Careful angling of the disks would also give thrust as the repulsive effects of the Discs would push the ships in whatever direction needed.

Telok
2008-02-15, 11:23 AM
Two suggestions.

First, get the old Spelljammer books/stuff. The prices and methodology of normal helms are horribly out of whack, but the other bits are good. It's also a great setting.

The basis premise is that spelljammer helms convert magical energy into lift and thrust. Stick a wizard or cleric in them and they lose all their spells for the day, but they can make the ship go (the speeds and spell loss methods here were pretty bad). They kept things pretty simple, minor helms had a lower maximum speed than major helms and higher level casters could go faster.

Illithid had series helms and lifejammers. A series helm was similar to a normal spelljammer helm except for three things, it never went faster then the slowest spelljammer helm, used spell like abilities instead of spells, and you could link multiples together for more speed. A lifejammer helm was like a normal helm except that it's speed was based off the hit die of it's victim and it drained hit points (and forced a save or die every day too).

Those were the major methods. There were also orbi, who were mutated mindless beholders that hive mother beholders used to power ships. Forges for the dwarven citadel ships. The neogi used mostly lifejammers. Gnomish sidewheelers mentioned using giant space hamsters, but never statted them out.

The big thing about spelljammer helms is that they didn't provide any real maneuverability. You still needed rigging and sails to do anything except go foreward and backwards. Although I think orbi were an exception to that.

Two last methods were furnaces and artifurnaces. Furnaces burned (literally) magic items, something like one day per 1000 gp value. They were sometimes used as backup helms. The artifurnaces ran off of artifacts, they never ran out but you had to deal with having a nice portable ten million gold value magic item on your ship. Those things were just trouble waiting to happen, plus they had a major artifact in them.

The easier method of having flying ships in D&D is to enchant multiple blocks of wood with permanent Levitation spells and build them into a ship. Enough of them will lift the ship and complete enclosure in the structure of the ship will protect them from Dispel Magic, having multiples also insures against having one or two fail for some reason. Once the thing is in the air a barrel with a permanent Gust of Wind in it will (depending on DM ruling about magic/physics interactions and catgirl murder) either provide direct thrust or reaction thrust if pointed at a sail.

Forum is acting up again. Slow slow posting.

sikyon
2008-02-15, 12:28 PM
Idea 2: Improved Immovable Rods strapped to a pair of giant wheels, as the rods pass a pair of contacts magical energy is channelled into them that turns them on and off again. This way only one rod is active at any one time. By adjusting the placement of the contacts from a position vertical to hub of the wheel to a position in the direction of turn or against it the turning of the wheel would cause anything attached to it to rise or lower as it stepped its way through the air. The angle between the contacts and the vertical determines pitch and the rotational speed of the wheels determines speed.
A Failsafe mechanism could be rigged so that if a small ball got raised off its plinth (as it would in the event of a sudden fall) all the Rods become active along with some emergency ones along the hull.
Hanging the ship by springs from the axle of the wheels would smooth the ride out considerably. Suited more to Societies with lots of industry.

This is going to be really slow, depending on how fast that wheel turns. Remember that immovable rods only support 8000 pounds. You'd need more than a hundred non moving immobile rods to keep a ship aloft.

Belial_the_Leveler
2008-02-15, 12:38 PM
Your ship is a colossal object. One Animate Objects spell later, it is a colossal creature. Apply permancy and a ring of flying.

The above is used for short-range maneuers only. For fast engines:

Take a 20 ft long adamantine cylinder. Apply Resist Fire, CL 20. On the inside of the cylinder there is a permanent maximised wall of fire, CL 20. The cylinder also Creates Water once per round. The Wall of Fire instantly vaporises it-the heat is enough to melt medium sized iron objects in 2 rounds so boiling water is not a problem. The steam created escapes through a hole in the back of the cylinder.

Congratulations-you now have a steam-powered, infinite fuel rocket.

BRC
2008-02-15, 12:39 PM
Congratulations-you now have a steam-powered, infinite fuel rocket.

That my friend, is awsome

sikyon
2008-02-15, 12:45 PM
Your ship is a colossal object. One Animate Objects spell later, it is a colossal creature. Apply permancy and a ring of flying.

The above is used for short-range maneuers only. For fast engines:

Take a 20 ft long adamantine cylinder. Apply Resist Fire, CL 20. On the inside of the cylinder there is a permanent maximised wall of fire, CL 20. The cylinder also Creates Water once per round. The Wall of Fire instantly vaporises it-the heat is enough to melt medium sized iron objects in 2 rounds so boiling water is not a problem. The steam created escapes through a hole in the back of the cylinder.

Congratulations-you now have a steam-powered, infinite fuel rocket.

I don't know how fast that sort of engine is going to push it. You're going to need a cold damage item to supress it when you want it off and you're going to want to be able to control how much water goes in in order to control the speed, so multiple lower level create water spells. The speed is going to need a fair bit of calculation though.

Pretty cool stuff.

BRC
2008-02-15, 12:46 PM
I don't know how fast that sort of engine is going to push it. You're going to need a cold damage item to supress it when you want it off and you're going to want to be able to control how much water goes in in order to control the speed, so multiple lower level create water spells. The speed is going to need a fair bit of calculation though.

Pretty cool stuff.

A decanter of endless water could work well to control the water flow.

Yakk
2008-02-15, 01:04 PM
The first thing you want is a look. The default look of your ships.

Let's go with:
A ship-like shape, sails spread around, and a ship steered by a wheel. Crew climbing on the rigging.

...

For the above to work, sails have to be useful. If we are using mostly real-life physics with magic added (ie not myth-physics, which is another option), for a ship with sails to steer it needs a keel.

The hull of a water ship exists for two reasons: first, it keeps the stuff it carries together, and second it acts as an extension of the keel. The first job will still provide a reason for it to look somewhat like a ship -- can we pull off the second?

...

So, the sails of an airship are astral sails, and the hull and keel is etherwood.

The astral sails catch both the real life wind and the astral wind.

The hull and keel exist in both our plane and in the etheral plane at the same time. Using secret shipbuilding arts, this allows the entire ship to "float" on the etheral sea. Height is controlled by letting ether in and out of the ship (so, ether pumps and hatches).

Note: etherwood doesn't float: it isn't lift-wood. It is only by sealing it into a large bowl-shape that it provides lift.

A hull-damaged ship starts leaking ether into it, and loses altitude.

The keel is also important, as it provides a force against which the ship can tack.

The construction of Astral Sails and Etherwood Hulls is both magical and involved.

...

Now, other cultures. The "ship hanging from flying whales" is too good of an image to use, but using it as a standard image isn't as neat. Some culture that doesn't have access to etherwood breeds the whales.

Etherwood barges, without astral sails, are used in barges. These barges are pulled along on ropes by animals.

Hulling an enemy ship becomes important -- so rams are key. But maybe the etherwood makes that hard to pull off reliably: the flow of ether deflected by the hull tends to make nearby lower airborn objects move erratically.

In addition, dropping is far easier than going up. Just open some hatches, and you plunge.

... alternatively, there could be an "etherlevel" that the ships float on. Down below the etherlevel, you can't catch the astral wind: all you can do is go up to the surface, bobbing up like a cork. The "etherlevel" varies from location to location and time to time.

Docking with the ground consists of furling your sails, and then allowing controlled ether leakage into your ship. This controlled fall is tricky: landing in water is the easiest way to handle it. As is taking off from water.

Areas where there isn't water to land/take off from are hard to deal with.

The whale-ship people, because they don't use astral sails, can move around in the under-ether. On the other hand, their whales are far easier to kill than a ship is to hull.

...

I like it!

So to sum up:
Etherwood, when formed into a bowl, floats upwards. Building a ship out of etherwood results in the ship floating up to the Etherline in the sky. Controlled leakage of ether (via portholes) can be used to lower oneself.

Once one is at the etherline, one can deploy astral sails. These catch both the normal and astral winds, giving you the ability to travel.

Using astral sails below the etherline isn't possible, as the wind is blocked by the ether.

One can use normal sails, but that is clumsy, and you are constantly working to try to control your height.

Another people who do not have access to etherwood has bred skywhales, and hangs their ships from them. They use harnesses and prods to make the whales do what they want, and possibly some magic. These ships can travel under the etherline, but are weak to attack by etherships (the whales are relatively easy to kill).

Landing and taking off is best done on water by etherships. Some inland ports build water harbors for airships to make landing easy. Smaller ports, well, landing is just hard there: ships designed for those areas have either harnesses or flat reinforced bottoms.

The level of the etherline varies from place to place and time to time. Some areas cannot be flown into because the etherline goes below the ground.

If you are hulled you start an uncontrolled descent. This is bad. Repair before you hit the ground, have your ship crash. Sometimes you can prevent death from a crash by slowing the descent, or aiming for water.

...

For some plot points:
* An empire has figured out how to forge etherwood's properties into metal.

* Etherpaddle boats, using magic to power the wheels.

* An area that has had sub-surface ether levels for centuries, and is relatively impassible, has just had an ethertide, and the area is now open to exploration. The ether levels are still unstable...

* A third method of traveling in the air is discovered.

* The largest sky-whale ship ever is used in war, turning the balance of power

ShneekeyTheLost
2008-02-15, 01:51 PM
It seems here as though you're looking at two main problems: Lift, and Propulsion. Both are required.

In a game I ran, I had some interesting ideas, which I now share:

First, the most economical version: The Floating Barge.

The floating barge is the most commonly used form of ALC (Above Land Craft) in use, due primarily to it's economical ease. In short, the effect is not unlike a very large wagon, which floats a foot or two above the surface it is traveling on. It may travel above solid or liquid, but may not use any form of gas, including heavier than air gasses, to travel on. It has no method of propulsion on it's own, although there are several options available. Most economical is simply an oxen team. Because it is floating in the air, it is much easier to haul than a normal wagon, and has far less worries about road conditions. Other methods are available, and described later.

The creation of a Floating Barge requires several enchantments to be placed upon the barge. This makes it, effectively, a magic item.

Floating Barge
Strong Transmutation, Strong Evocation CL 12th*. Craft Wondrous Item, Floating Disk, Levitate, Creator must have 8+ ranks in Knowledge (architecture and engineering). Price: 2,500 per 5' square of cargo space. Each square of cargo space can carry up to 500 lbs of cargo.

* Even though Floating Disk and Levitate are 1st and 2nd level spells respectively, the additional magical power necessary to push the normal spells beyond their means drastically increases it's caster level.

Note: You may make a walled floating barge, however the wall takes up the 5' around the barge, making it unable to carry cargo in that square. Thus a 3X3 walled barge would only have one square available for cargo. However, the walls will provide protection for the cargo within. This is most economical when used on the larger barges. Various walls are available, at various prices depending on what materials are used.

The next most economical is a Blimp. This floats through the sky at higher altitudes than the floating barge, making ground conditions completely irrelevant. The lighter-than-air gasses found in the blimp are created through the use of a high-powered variation of Major Creation.

Methods of Propulsion

First, we have the TK Engine, which is a magic item.

TK Engine.
This is a simple device which attaches to a propeller/screw/paddle. It turns what it is attached to in a pre-programmed pattern, which provides forward movement. It is, in effect, a Telekinesis spell which has been Permanencied. This does not generally make for rapid travel, but it is at least not fatiguing on anyone.

Minimum Caster Level 13th. This costs 2,500 xp from the mage creating the engine. Requires both Telekinesis and Permanency

Next, we have the Gust of Wind Sail.

In short, it's a sail placed on an ALC with a Gust of Wind spell Permancied and aimed at it. Generally, it has some sort of method of blocking the Gust of Wind (i.e. containing it within a metal box with a shutter).

The mast for the sail takes up one 5' square in a Floating Barge. The compartment for the Gust of Wind takes up another 5' square. Both may be built high enough as to avoid disturbing the rest of the cargo.

Squash Monster
2008-02-15, 02:44 PM
How to power the airships in your setting depends on how common you want airships to be. If they're a status symbol of the rich, you want a pretty expensive method of creation. If everybody's got one, you want something cheaper.


For a more affluent way of making airships, look at the spell Reverse Gravity. The spell effect notes that if your target reaches the top of your area of effect without running into anything, it will hover at the top of the area, bobbing slightly, until the spell runs out. So, we will create an item that continuously emits the spell Reverse Gravity in a spread underneath itself, and put it our ship. The ship will hover on top of the area of effect. The item should be mounted in a way that allows it to be moved slightly. If we lower it a little, our ship will enter freefall, as the field is constantly too low to hold up the ship. If we raise it a little, our ship will enter freefall upwards. Obviously, a steady hand is needed for this.

Using the magic item creation rules of thumb, an item that has the continuous effect of a spell costs:
Spell level * caster level * 2000gp
With an extra 4x multiplier for spells with durations of rounds per level.

For reverse gravity, that's 728,000gp, or half that for the creation cost (364,000).

That's a level 13 reverse gravity, affording you six 10ft cubes of effect, or 600 square feet of buoyant area. This should be able to hold up a ship (remember that you only need support some of the ship, if most of it is pretty sturdy).

Once you've done that, making a similar item that casts Wind Wall or similar allows you to make sure you always have wind in your sails.

This system is largely safe (unless somebody casts Disjunction on your lifter), unless you go to the area immediately under the ship. A 10 foot area under the ship is under the effects of a Reverse Gravity spell, so if the ship parks too close to the ground there may be debris.



For a much cheaper way of making airships, we need a lot more moving parts. Take a large number of Immovable Rods, and put them inside a treadmill with their buttons facing out one side. Have a well-positioned piece of angled metal at both ends of the treadmill to press the buttons on the rods as they pass by. The rods moving forward should be off (no resistance) while the rods moving backwards should be on (immovable). As long as you have enough rods so that half of them can support the entire weight of your ship, this can hold you up. Now you just need handcranks and some slaves to power your treadmill. (Or a decanter of endless waterwheel).

tsuuga
2008-02-15, 04:46 PM
Airships based on existing magic items just don't seem efficient. Carrying a hull around is pretty inefficient, as lifting capacity costs money. So what a lot of ships (that aren't warships, anyway) would look like is simply the drive mechanism with cargo just strapped to it.

I love the idea of an airship driven by a treadmill of Immovable Rods. A decanter of waterwheel or a heavy horse provides the locomotion. The problem is you need at least 6 immovable rods to ensure that 2 are always active for stability, you need some sort of frame attached with gears to the treadmill to hold the 7 tons of excess capacity, and both the treadmill and the frame would have to be pretty darn strong. You're probably better off skipping the frame altogether and using portable holes (the weight limits on bags of holding render them incapable of holding dense things.) for essentially unlimited cargo storage. A portable hole can carry 282 cubic feet of material (according the Arms and equipment guide and this page (http://www.simetric.co.uk/si_materials.htm), 10720 GP worth of barley (at 1 GP/lb), for instance)

Therefore, assuming a cargo of barley, you can expand the cargo capacity of the ship by 4 tons for 10,000 gold, or by 5 tons for 20,000 gold. Assuming a cargo denser than grain, however, the portable holes pull ahead. If your cargo is iron, a portable hole expands the cargo by 69 tons for 20,000 gold. The tipping point is about the density of ice (909 kg/m^3, on the table I referenced)

If you're feeling like something a little weirder, give a flesh golem a pair of immovable rods. He can use them like monkey bars. It's slow, but he'll get there, and he's better able to protect the shipment than a guy and a horse in a treadmill. If you've got a specially designed flesh golem (ranks in tumble or some such) it can brachiate or use centrifugal force to sling itself through the air at some pretty great speeds. Total cost 30,000 gold + 20,000 per portable hole.

But... there's gotta be some reason that a guy with a flying mount cant just drag the portable holes around, much faster and cheaper.

JeminiZero
2008-02-15, 05:35 PM
I don't like the idea of using Force bubbles to create indestructible balloons, using that logic you wouldn't ever need another building material, ever.


There's a difference between having an indestructable balloon and an indestructable ship. You still need mundane materials to attach the force sphere balloon to the the passanger cabin. And if sufficient damage is done to the attachment, the link is broken, leaving the balloon free to rise up, and the cabin to plummet. Besides, Force sphere is virtually, but not totally indestructable, and can be brought down using e.g. disintegrate.

FlyMolo
2008-02-15, 07:25 PM
I like force bubble balloons. You'd never need another building material ever, but think of the casters you'd need to build even the simplest building. Even a hut would require 5 walls of force. That's costly. Wood is cheaper and easier to find. Supply and Demand, baby.

Etherwood is fun, but that's a whole new setting nucleus.

Permanencied Reverse Gravity on a ship. Or the aforementioned Permanent Reverse Gravity which hangs from the ship. And a steady hand isn't necessary, as part of the ship would be affected and negative weight, while part would be positive weight. They'd balance, but you could get up to free fall in either direction, or any value in between.

For lateral propulsion, sails don't really work. No keel to push against. I recommend the steam rocket espoused earlier, or some decanters of endless water.

Megafly
2008-02-15, 07:34 PM
A Galley might be fun.You make the boat levitate to be almost neutrally buoyant and have a hundred slaves rowing across the sky with oars based on Immovable rods . The best part is that you could shanghai the PC's and force them to row!!

I really would like to pull some kind of thing with harpoons and Cloud Rays from together like Sand Worms in Dune

Citizen Jenkins
2008-02-15, 07:45 PM
I would suggest the following:
1. Slaughter an appropriate number of Griffons, Hypogriffs, Wyverns, and other large mid-low level flying monsters.
2. Zombify them.
3. Attach a flying rig or attachment for the cargo/crew.
4. Put the zombies in a giant balloon. Use lanterns to keep it inflated.
5. Always use terms like "cross-dimensional spatial interference" and "psychic-divine mutability steering" when talking about your airship. Hyphens are your friend.
6. Steadfastly maintain that you can't smell anything.
7. Profit.

Say you went out and killed 5 Hippogriffs and used them as propulsion. They could carry over 1000 pounds at 100ft a round without ever getting tired or needing upkeep. All this would only cost 750 gold+flying rig.

Plus there's always that wonderful moment where the sky pirate/wizard/BBEG throws a fireball at your giant balloon expecting it to explode in a helium fulled fireball only to be thwarted by your secret form of propulsion.

-"Flying Zombies! I can't believe I never thought of it before!"
-"It will revolutionize the industry."

Randel
2008-02-15, 10:40 PM
Okay, here are a variety of approaches/vehicles. All fluff.

1. The Giant Peach
Infused with some of the most powerful druidic magic in existence, this common fruit has grown to truly immense proportions. Transmutation magic has given the peach the ability to regenerate breaks in it and slowly regain mass. Thus its occupants can dig into the peaches edible flesh and consume it while being certain that they will not simply eat the whole thing. Its mass is also magically lightened to the extent that it can be carried through the air rather easily.

One common (if unusual) way of granting it flight is to simply wait for a large number of birds to swoop down to eat it. Then grab the birds and tie a long silk string to the birds legs and affix it to the stem of the peach. Once sufficent numbers of birds are so attached, an animal handler can order them to fly and the combined lift of the thousands of birds can carry the peach through the air. The peaches regenerative properties provide enough food to sustain the birds carrying it along with its occupants.

One should be very careful with this exotic vehicle do to the danger of vermin infestation, the incredible sticky environment, the danger that the peach will regrow enough to seal its occupants inside forever, and the fact that nobody will take you seriously if they see you flying around in a giant fruit.



2. The Cloud Ship
Those knowledgeable in magical weather patterns have always realized that some cloud formations can posses a hardness almost equal to that of solid ground. Often resulting in strange winged humanoids and the occasional giant making cities in the clouds. However, it is not until recently that human wizards have been able to magically create these clouds near the earth.

The Cloud Ship is an ordinary water-traveling vessel that is equiped with a hard-cloud generator. This creates a billowing and buoyant layer of cloud beeith the vessel that slowly lifts the ship into the air. Essentially creating a soft but firm bit of ground in it that slowly rises to optimal cloud-height as more of the cloud is made. The ship may then sail at an altitude of hundreds of feet in the air with rolling waves of cotton-white clouds beneath it much like an ocean. It is difficult to see down through the clouds so navigators must either check the stars to determine where they are or lower someone with a rope to try and climb down through the hard clouds to peek down at the land below.

Being artificially created, the hard clouds slowly dissipate if the generator is shut off but it rarely dissipates fast enough to make the craft fall. It simply drifts ever slowly down until it touches land or water. If the craft reaches a naturally occurring formation of hard-clouds then the ship can either sail through it as if on water or it will bump into it and its crew must explore on foot... depending on how hard the cloud is.


3. Extra Large Flying Carpet
Often used by the very rich to travel through the air in style.

ashmanonar
2008-02-16, 12:00 AM
No No by all means do it! It was my way of saying no current technology. If it is magical, not scientific please do it! It sounds great!

Oh and I belive you would need a Decanter of Endless Diet Coke and Summon Mentos III.

I may have to create a custom Decanter of Endless Mountain Dew one of these days. If I had a wizard character, it'd be even better.

Talic
2008-02-16, 12:09 AM
Alternately, Enchant the keel with Levitation. This allows for gentle rise and fall, and captures the ship feel. Ballast the Keel to be exceptionally heavy, so as to keep down STAYING down. There's the air part.

Now for the ship. It doesn't work if it won't go where you want. Thus, the spell I'll be using is Gust of wind. Enchant a few dozen or so crystals to shoot the effect constantly. Place each at the front of a 40' tube. Valve systems can redirect the flow of air downward, for no effect, or to focus it out a 6 inch diameter shaft, 10' long (think funneled down from the 5 foot torrent of wind to 6 inches). Exit Speed from the 6' shaft should be roughly 500 miles an hour.

The 10:1 pressure amplification should provide enough power, with 20-30 of these, to move a small ship. Add in a rudder system for the exhaust, and you've got steerage. Likely, you could put storage right above the exhaust, for refrigerated storage. Heat would be generated at the beginning of the funnel section, and could be leeched off with water to provide heating for the ship.

And there, is a stately Gnomish air-yacht.

EDIT: Note, this design will likely have rattling components, even if enchanted for strength. Likely, also, it will have a high pitched whistle sound also (in fact, a couple fluted holes on the exits could guarantee this... Clever use of valves could even be worked to play very simple melodies, which could be useful to impress when pulling in somewhere). This is ok. Rattling components are a basic part of gnomish design.

Also, with further calculations, a 100' ship, rated at 500 tons (thin metal hull, or thick thick wood), could likely, after a few minutes of acceleration, reach speeds approaching 40 miles an hour, with 20 of these.

Raum
2008-02-16, 12:16 AM
Well, if you want air ships to be rare consider this...

Rumjal Wyvrnslayer leaned tiredly on the dragon's corpse. He and his crew had succeeded after all these years! Shmakil the Red was dead! Looking mournfully at the burnt ruins of his proud ship, he knew he had a problem. The island wouldn't was too barren to support them, and had little avaiable to construct a new ship from. Looking back to the dead dragon, he called to his crew "Start carving it up boys, we'll make sails from the wings and frame the ship with the dragons ribs!"

Imagine his surprise when the ship sailed the sky as easily as the ocean...

Thamir
2008-02-16, 04:58 AM
Well, if you want air ships to be rare consider this...

Rumjal Wyvrnslayer leaned tiredly on the dragon's corpse. He and his crew had succeeded after all these years! Shmakil the Red was dead! Looking mournfully at the burnt ruins of his proud ship, he knew he had a problem. The island wouldn't was too barren to support them, and had little avaiable to construct a new ship from. Looking back to the dead dragon, he called to his crew "Start carving it up boys, we'll make sails from the wings and frame the ship with the dragons ribs!"

Imagine his surprise when the ship sailed the sky as easily as the ocean...

What is that from? Ah well I love the ideas guys keep 'em coming

tsuuga
2008-02-16, 09:42 PM
Hmmm... Thinking about it, a sphere of force seems a bit more reasonable as a method of lift. A 100-foot diameter sphere would cost 226200 GP, permanencied, assuming the DM rules you can actually cast Wall of Force that way, and assuming the walls of force are CL 20 (lower CL makes it more expensive). Then, you open a gate to some airless place inside the sphere (1530 GP). Assuming the walls of force are 6 inches thick and have density equal to air, your bubble now has a lifting capacity of 34384 pounds at sea level. A 200-foot diameter bubble has a lifting capacity of 293378 pounds and costs 891250 GP. A 300-foot diameter bubble would lift about a million pounds and cost about 2 million gold. Obviously, it is wise to have some sort of net ready before you cast the Gate. A ship could use modified Figurines of Wondrous Power (for instance, cartoonish one-ton weight) as ballast.

Going up to the edge of the atmosphere to retrieve an escaped flotation bubble could be an interesting adventure.

Talic: If the keel is where you put the ballast and also where the lift comes from, it does nothing to keep the ship level. You would need to either suspend weights from the keel exceeding the weight of the ship, or enchant something farther up the ship. That said, it would cost 1675000 GP to permanently levitate 500 tons, assuming that you could permanency levitate, which you can't. (I assumed that the minimum CL to permanency levitate was 9.) You could make magic items of use activated or continuous levitate, but each ton would cost you 160,000 GP to lift (spell level 2 x caster level 20 x 2000 Use Activated or Continuous x2 Duration in minutes)

I like the idea, it's just really bloody expensive according to the RAW.

I'm tired of doing calculations

FlyMolo
2008-02-16, 10:06 PM
I wonder if I should drop an airship on my players, and see if I can convince them to go retrieve the forcebubble?

Could be a cool Side Quest.

Ah! Reading Tv tropes too long. Capitalized links eek.

Gwyn chan 'r Gwyll
2008-02-16, 10:27 PM
The hulls are shaped like galley hulls, but streamlined in more than one way, and with no open deck. The deck is covered with sheets of metal several inches thick. There are several sizes of ships. The smallest is 10 rowers. A Unireme. The normal size is Trireme. Big ships are Quinqireme (correct me on spelling. However, huge decaremes exist. A decareme has hundreds of rowers, and is a mighty sight indeed.

The rowers are used for extra maneouverability, and most of the power comes from masts, with Uniremes having 1 mast on the top and 2 minimasts on the sides, Triremes having 2 on the top and 1 on each side, Quiqiremes have 3 masts on top and 2 on each side, while the Decareme has 20 masts on top, and 5 on each side. These masts are collapsable, falling flat against the ship, and can twist and pivot to catch the wind. Skilled pilots can maneuover as well as rowers with these sails, however must use their rowers to pull on adamantium fibre ropes to move the sails.

These ships mostly use jetstreams to move, control of jetstreams being strategical in warfare. However, where jetstreams aren't, they use multiple methods. Some pilots flap the sails, propelling the ship forward this method requires the least manpower, but is the most unwieldy. Most pilots use the immovable rod technique. However, the best pilots dip and glide, relying on their speed and aerodynamic shape to keep them moving, changing their sails at a moments notice.

I'll post on their "engine" tomorrow. I'll also write a bit about warfare in these things. The visual of this design just amazes me. The Decaremes moving slowly through the air, oars scything through the thin air in perfect sinc, while Duoremes (yes, there are duoremes, their like sloops) leap gracefully through the air around them, like dolphins around a frigate.

Thamir
2008-02-17, 02:22 AM
You don't really need to calculate price, I can do that.

Sir Giacomo
2008-02-17, 04:06 AM
Jemini, that is a horrid idea, not only are you making hydrogen gas, you are making oxygenated hydrogen gas.

You could try to use polymorph any object for helium gas and thus have a more resilient Zeppelin.

- Giacomo

Jothki
2008-02-17, 05:14 AM
Any system that just involves pulling mass that's already in motion from somewhere and simply letting it shoot out won't work. If the mass starts with a fixed velocity and exits with that velocity completely intact, the momentum of the craft itself wouldn't have been affected.

On the other hand, shooting that mass at a sail or similar blocking object like a bend in a tube would probably work fine.

Lyinginbedmon
2008-02-17, 07:23 AM
Let me see...
A large array of auto-casting mage hand devices. Each one produces 5 pounds of lift for the ship, and each one in the main engine is going to move the ship 5 ft. once all the weight is accounted for.
Something based around reverse gravity, causing the engine (Along with the attached ship) to "fall" towards it's destination in a straight line at significant speed. Given that falling goes 150 to 300 ft., that's 17 mph in the first round and then 34 afterwards. Maybe you could stack the effects for higher speeds?If you move up the line on the kind of knowledge of chemistry and physics the engineers have you can get some pretty cool stuff.

seedjar
2008-02-17, 08:18 AM
Cloudwalking effects? You could use any number of the above 'pull it with creature X' ideas.
To play off of Randel's Cloud Ship, you could create a light cloudwalking vessel and propel it along even mundane clouds. If you put a fog cloud type of effect at the stern, you could surf down the rising fog. The image that comes to mind for me is kobolds riding a rickety old airboat down a wave of clouds.
~Joe

Lyinginbedmon
2008-02-17, 08:57 AM
Something based around reverse gravity, causing the engine (Along with the attached ship) to "fall" towards it's destination in a straight line at significant speed. Given that falling goes 150 to 300 ft., that's 17 mph in the first round and then 34 afterwards. Maybe you could stack the effects for higher speeds?

"Drizz't! Prepare for-"
"Waah!"
"-extreme acceleration..."

:tongue:

Talic
2008-02-17, 09:02 AM
Hmmm... Thinking about it, a sphere of force seems a bit more reasonable as a method of lift. A 100-foot diameter sphere would cost 226200 GP, permanencied, assuming the DM rules you can actually cast Wall of Force that way, and assuming the walls of force are CL 20 (lower CL makes it more expensive). Then, you open a gate to some airless place inside the sphere (1530 GP). Assuming the walls of force are 6 inches thick and have density equal to air, your bubble now has a lifting capacity of 34384 pounds at sea level. A 200-foot diameter bubble has a lifting capacity of 293378 pounds and costs 891250 GP. A 300-foot diameter bubble would lift about a million pounds and cost about 2 million gold. Obviously, it is wise to have some sort of net ready before you cast the Gate. A ship could use modified Figurines of Wondrous Power (for instance, cartoonish one-ton weight) as ballast.

Going up to the edge of the atmosphere to retrieve an escaped flotation bubble could be an interesting adventure.

Talic: If the keel is where you put the ballast and also where the lift comes from, it does nothing to keep the ship level. You would need to either suspend weights from the keel exceeding the weight of the ship, or enchant something farther up the ship. That said, it would cost 1675000 GP to permanently levitate 500 tons, assuming that you could permanency levitate, which you can't. (I assumed that the minimum CL to permanency levitate was 9.) You could make magic items of use activated or continuous levitate, but each ton would cost you 160,000 GP to lift (spell level 2 x caster level 20 x 2000 Use Activated or Continuous x2 Duration in minutes)

I like the idea, it's just really bloody expensive according to the RAW.

I'm tired of doing calculations


First, the ship lurching a bit is fine, as long as the bottom is measurably heavier than the top, it's good. Second, I was actually thinking of the pipes on the sides.

Third, fly can't be made permanent either. Does that mean we can't make carpets of flying? Magic item rules are different than spell + permanency. Something like this likely would cost hundreds of thousands of gold. But the average weight of a 500 foot long ship is 9,000 tons. 250 feet would be 1125 tons, by D&D doubling weight rules. 125 feet would be 141 or so tons...!? Wow, it's a lot lighter to work. Only need 10 tubes, Speed will be around 70 mph, and make it a lot easier to build. This thing ain't just a yacht, it's a speed boat... Cloud Skiing, here we come!

Or, to borrow off the idea above, enchant large weights topside to be under the effects of Reverse gravity. Remove bottom ballast. The ship's weight will hold it in the air, and, simply by sliding the heavy weight along a track, you can adjust the amount of beam in the reverse grav field, and thus the amount of lift, and thus control lift and descent. That'd be more of a warship design though, with slaves hauling the incredibly heavy beams as needed. Magical grease would help.

Citizen Joe
2008-02-17, 09:18 AM
Let me approach this from the DM's perspective to keep the game balanced and on track. You could have magical ley lines or something that travel through the air is a weird spiderweb that covers the world at various altitudes. Now your main vessels are able to travel from city to city by riding on these lines. Some vessels have been equipped with gliding capacity so that they can jump the rails and glide over to a nearby line to continue in another direction. For this, you will need a special magically/psychic sensitive creature that can 'see' these lines in order to map out routes. Meanwhile 'drop ships' can glide off the main bodies to specific locations and then use essentially balloons to lift them back into the air (usually empty) where trained pteradactyls or something bring the spent 'drop ships' back to the mother ship.

This allows for rapid transit between plot important places without players hijacking the game on their own agenda.

bosssmiley
2008-02-17, 09:29 AM
OD&D flying ship creation: Champions of Mystara (http://paizo.com/store/downloads/wizardsOfTheCoast/classicDAndD/mystara/v5748btpy7mvw) - everything from dragon-towed longships to soul-infused elemental vessels to gnomish Zeppelins and artefact powered Warbirds.

AD&D flying ships: all things Spelljammer. Plus the 3rd Ed update from Dungeon #92.

Needs more floating fortresses and could castles... :smallwink:

Magnor Criol
2008-02-17, 10:21 AM
Your ship is a colossal object. One Animate Objects spell later, it is a colossal creature. Apply permancy and a ring of flying.

This has some great potential for interesting story points; a living ship, that you can - and have to - interact with. Just make sure no one starts dating it, then breaks up in the middle of a firefight a la Futurama. =p

Seriously though, it could be very interesting for the campaign. Make all airships be animated creatures, but with intelligence - via some specially modified version of the spell - and you have an NPC the characters can interact with anytime they want to when they're on the ship, and it could make for some nice plot hooks (rogue airships, airships rebelling at being mistreated, etc.)

tsuuga
2008-02-17, 11:43 AM
To borrow heavily from Tales of the Questor:

Major cities set up a network of Ley-currents, each of which is essentially a band of magnetic force. Airships are suspended from metal poles which are magically polarized, and by reversing the polarity you reverse direction.

There's really little reason to have airship hulls be as heavy as a watership hull. A regular ship hull sits in water, all the time. It'll eventually waterlog and become much heavier. An airship hull can stay much drier, and thus much lighter. Since it doesn't have to be waterproof, it can even be a basket for the smaller ships. Orrrrrr you could use force effects for a glass-bottomed and extremely light hull.

A reverse-gravity weight is cool... in fact, you could have basically 2 ships in one. You've got your regular gravity hull, with a metal plate attached 10 feet above it, and the counterweight is an identical hull. You'd still need some way to generate lift, since perfectly balancing the ship to be weightless is basically impossible, thus the ship would drift up or down. It's much simpler to have a small gas envelope, capable of lifting maybe a ton, and load the bottom ship heavier. This would be necessary to keep the ship stable, as well... otherwise it might just spin.

Citizen Joe
2008-02-17, 12:26 PM
Again to play off the ley line rapid transit idea...

Clearly, someone needs to be able to sense the ley lines in order to chart them. However, it may be possible for very powerful people, or groups of people, or special devices that can bend the ley lines slightly so as to enable a ship to get close enough to another ley line to jump to it mechanically. This would likely be restricted to military vessels, since it would allow heavier ships to jump lines. Meanwhile, other vessels may use gliding technology to jump lines. These glider ships would have to be lighter because the will be free of the supporting ley lines during transition. Heavy lift merchant vessels would not jump lines at all, but rather travel from port to port on a single line.

I also recommend MUCH slower free flying vessels akin to a balloon towed by flying creatures.

You should be very wary of this technology because it will drastically affect the nature of commerce and trade. Also, populations and cultures will become very mixed.

Thamir
2008-02-17, 08:49 PM
I like the weights and sails system of the edge chronicles. I like somthing not to magical but not all together scientific.

shadow_archmagi
2008-02-17, 09:03 PM
High powered industrial rod of magic missile firing downward. Bolt of force hits lever which is attached to wings. Wings flap. Airship flies. Problem solved. Sail on top provides directional momentum.

Hawriel
2008-02-17, 10:13 PM
Yeah. First smart caster who uses fireball, it goes up like the Hindenburg (sp?). Nice abuse of Storm Bolt though.

thats a myth

The hydrogen gass was not the cause of the fire nor the reason it was so consuming. The paint on the skin of the zeplin was set on fire by static electricity. The static was not properly grounded do to a desine flaw or a flaw in the structure whare the fire started. Cant remember which off hand. This allowed a static charge to build up, when it sparked off it ignited the paint and oil in the skin of the zeplin. The ignintion of the hydrogen gass was a natural side effect of this. The fire you see in the film of the desaster is the skin and frame burning. Hydrogen gass burns clear and fast. The gass was also partitioned in cells, for just such an occassion. The Hindenburg burned from the outside in not from the inside out. Any why hydrogen is a perfectly vable gass to use for an airship. If porperly handled.

Seeing as if an airship is made with hydrogen is being used in a high magic world. Im sure the makers and users of such a ship would be well aware of the properites of the gass and how to handle it. Im sure protection from elements fire and elictricity would be permenantly enchanted into the ship.

BRC
2008-02-17, 10:18 PM
Seeing as if an airship is made with hydrogen is being used in a high magic world. Im sure the makers and users of such a ship would be well aware of the properites of the gass and how to handle it. Im sure protection from elements fire and elictricity would be permenantly enchanted into the ship.

Would they, I mean, knowledge of hydrogen gas is a fairly recent thing, and especially since in a high-magic world most of the brilliant minds that would study science instead study magic (which is preety similar), i doubt there would be that much knowledge concerning chemestry that couldn't be used to make potions.

FlyMolo
2008-02-17, 10:33 PM
Trial and error. How many times do I have to demonstrate that this stuff explodes before you take steps to make sure it doesn't?

Citizen Joe
2008-02-17, 11:20 PM
Actually, hydrogen gas implodes. A given volume of hydrogen gas will reduce to water at about 100,000 to 1. It is flammable, but it isn't really explosive. On the contrary, if you can saturate hydrogen gas with oxygen gas without touching it off, a single spark could collapse a balloon almost instantly. Hydrogen gets a bad rap because of the Hindenburg, which actually caught fire due to the doping compounds on its skin. The hydrogen only aggravated the situation, but it actually took a while for the Hindenburg to burn, compared to an actual explosion (34 seconds compared to 50 milliseconds).

All that being said, yes hydrogen is flammable... yes hydrogen is dangerous... and hydrogen gas is anachronistic, requiring some sort of natural process to yield the gas in order to maintain the fantasy element.

By contrast, hot air balloons would be safer and more in keeping with the fantasy element.

Worira
2008-02-17, 11:54 PM
Strength-cheesed flying creature. Since they can fly with a light load, a colossal quadrupedal flying creature with strength 100 could carry 94,887 metric tonnes.

Thamir
2008-02-18, 12:40 AM
thats a myth

The hydrogen gass was not the cause of the fire nor the reason it was so consuming. The paint on the skin of the zeplin was set on fire by static electricity. The static was not properly grounded do to a desine flaw or a flaw in the structure whare the fire started. Cant remember which off hand. This allowed a static charge to build up, when it sparked off it ignited the paint and oil in the skin of the zeplin. The ignintion of the hydrogen gass was a natural side effect of this. The fire you see in the film of the desaster is the skin and frame burning. Hydrogen gass burns clear and fast. The gass was also partitioned in cells, for just such an occassion. The Hindenburg burned from the outside in not from the inside out. Any why hydrogen is a perfectly vable gass to use for an airship. If porperly handled.

Seeing as if an airship is made with hydrogen is being used in a high magic world. Im sure the makers and users of such a ship would be well aware of the properites of the gass and how to handle it. Im sure protection from elements fire and elictricity would be permenantly enchanted into the ship.

Yes, though it provided fuel for the fire the hydrogen did not start it. The Hindenberg was a triumph, it was going to spawn a new age of zepplin travel. And therefore they wanted to boast and painted it with a metalic paint as they did its predecessor. They jointly travelled around the world spreading zeppelin mania, until the Hindenberg cought fire killing many of its passagers and tumbling to the ground. It was caused by static electricity whether it was discharged onto by lightening or it was simply generated by the air resistance. (I love zepplins but I don't want to put them in my campaign world.)

Talic
2008-02-18, 06:27 AM
thats a myth

The hydrogen gass was not the cause of the fire nor the reason it was so consuming. The paint on the skin of the zeplin was set on fire by static electricity. The static was not properly grounded do to a desine flaw or a flaw in the structure whare the fire started. Cant remember which off hand. This allowed a static charge to build up, when it sparked off it ignited the paint and oil in the skin of the zeplin. The ignintion of the hydrogen gass was a natural side effect of this. The fire you see in the film of the desaster is the skin and frame burning. Hydrogen gass burns clear and fast. The gass was also partitioned in cells, for just such an occassion. The Hindenburg burned from the outside in not from the inside out. Any why hydrogen is a perfectly vable gass to use for an airship. If porperly handled.

Seeing as if an airship is made with hydrogen is being used in a high magic world. Im sure the makers and users of such a ship would be well aware of the properites of the gass and how to handle it. Im sure protection from elements fire and elictricity would be permenantly enchanted into the ship.

Buzz! Wrong, thanks for playing though. The flammable paint concept is the actual myth. It was shown on MythBusters that the ship with oxidizing flammable metals in the paint (at a percentage of about 6%, if I remember correctly) was no more likely to catch on fire or burn faster than a ship without. In fact, at that level, the paint was unable to catch on fire, when helium was used as a lift agent. It WAS the highly, highly explosive hydrogen gas that caused the burning. The hydrogen did not start the fire, any more than the other agents of the fire pyramid did. (Oxygen, heat, chemical reaction). It's the presence of all of them together that causes the reaction, and the hydrogen is equally culpable. Oxygen is hard to remove, as it's in the air. Certain soapy liquids and foams can do this, in modern firefighting, if the fire is on a solid surface. The chemical reaction is hard to remove, though some chemicals in modern society, such as potassium bicarbonate, can accomplish this. Heat, also hard to remove, as the sun radiates many things, static electricity can build and provide local heat, but the simple fact is, if the hindenberg were lifted by helium, it would NOT have been a falling fireball.

Also, hydrogen does not implode upon itself. It burns, same as any other highly flammable substance. When combined with oxygen, a necessary catalyst for any fire, and also present in the atmosphere at a concentration of 21% or so, it provides a deadly mix, as the amount of heat required to set it off is relatively low. It burns incredibly rapidly, which is the definition of an explosion. Extremely fast combustion.

This concludes the physics lesson for the day. I hope it's dispelled some of the myths and falsehoods running rampant in this thread.

Citizen Joe
2008-02-18, 08:58 AM
Also, hydrogen does not implode upon itself. It burns, same as any other highly flammable substance. When combined with oxygen, a necessary catalyst for any fire, and also present in the atmosphere at a concentration of 21% or so, it provides a deadly mix, as the amount of heat required to set it off is relatively low. It burns incredibly rapidly, which is the definition of an explosion. Extremely fast combustion.

Compared to true explosives, I don't consider burning hydrogen gas to be fast. Touching off LIQUID hydrogen would be explosive, since it has to grow to tremendously to vaporize. I think the distinction I make is that explosions have a concussive effect from rapidly expanding gases whereas gaseous hydrogen combines with oxygen to form water and thus shrinks away tremendously.

Dan_Hemmens
2008-02-18, 09:39 AM
Would they, I mean, knowledge of hydrogen gas is a fairly recent thing, and especially since in a high-magic world most of the brilliant minds that would study science instead study magic (which is preety similar), i doubt there would be that much knowledge concerning chemestry that couldn't be used to make potions.

Furthermore, since D&D obviously *doesn't* follow real world laws of science, chances are there actually *isn't* such a thing as Hydrogen gas.

Of course you could always use phlogiston.

Talic
2008-02-18, 09:41 AM
http://www.boc.ebcnet.co.uk/hydrogen/properties/index.html

http://www.gas-plants.com/hydrogen-properties.html

http://en.wikipedia.org/wiki/Hydrogen

All state hydrogen to be highly explosive when combined with oxygen.

That you don't consider it so does not invalidate that. Rather, it shows that your view of hydrogen is a bit skewed. Hydrogen fuels stars, is the fuel of choice for sending multi-ton vehicles into ORBIT, requiring over 22,000 miles an hour. Believe me, it is HIGHLY explosive. The only thing that slowed the hindenberg's burn rate down was the rate that oxygen could mix with the hydrogen.

Talic
2008-02-18, 09:44 AM
Furthermore, since D&D obviously *doesn't* follow real world laws of science, chances are there actually *isn't* such a thing as Hydrogen gas.

Of course you could always use phlogiston.

True, because in D&D 1+1 does not equal 2, without some force acting upon objects, they randomly DO fly off in random directions, and fire doesn't burn wood.

Oh wait, no, those are still all true. D&D, at its core, just adds "magic" as another form of energy. It does not specifically refute any laws of physics or science. Well, a few concerning doubling and weight carrying and such, but that's more improper estimation than outright rewriting of the laws of nature.

Bayar
2008-02-18, 09:46 AM
Levitation chambers, so that it could take off...or maybe a steam engine running on a level 5 continuos burning hands enchantment...or something...

Dan_Hemmens
2008-02-18, 09:50 AM
True, because in D&D 1+1 does not equal 2, without some force acting upon objects, they randomly DO fly off in random directions, and fire doesn't burn wood.

Oh wait, no, those are still all true.

You assume all of those things are true. In fact objects in D&D fly off in random directions without forces acting on them all the time - that's what the Fly spell does for a start.


D&D, at its core, just adds "magic" as another form of energy. It does not specifically refute any laws of physics or science. Well, a few concerning doubling and weight carrying and such, but that's more improper estimation than outright rewriting of the laws of nature.

The problem is that "magic" isn't a form of energy. If it was, it wouldn't work the way it does.

Most obvious example: it is aerodynamically impossible for dragons to fly. Do they fly with magic? Then why can they fly in an antimagic field? And why do they have wings in the first place?

Fishy
2008-02-18, 10:04 AM
Get yourself a mundane ship, with sails, keel and rigging, a Horn of Fog (http://www.d20srd.org/srd/magicItems/wondrousItems.htm#hornofFog) and (this is the hard part) a dead Silver Dragon (http://www.d20srd.org/srd/monsters/dragonTrue.htm#silverDragon).

Handwave that the silver dragon scales inherit the Cloudwalking effect, and use them to coat the underside of the boat. Build the Horn into the prow, and either blow it in shifts, enchant it to play itself, or get a Warforged Bard. Play louder, the cloud gets thicker and the boat rises, play softer and the boat starts to drop. Not the most stealthy contraption in existence, but I love the image.

Hawriel
2008-02-18, 05:20 PM
hmm I'll take PBS and their documentaries over the Myth busters any day.



Michael Stakpose used airships in his book Eyes of Silver

http://www.sfsite.com/01b/eye49.htm

Instead of an engine room he had medatation chambers that wizards would take turns in. The chamber was a magical place that would levetate the ship. I cant remember if they provided propultion as well, or if they used sails or props. Been awile sence I read the book. Any way depending on the size of the ship there could be up to two or three chambers, requiering more than one wizard to man them.

sikyon
2008-02-18, 06:31 PM
Actually, hydrogen gas implodes. A given volume of hydrogen gas will reduce to water at about 100,000 to 1. It is flammable, but it isn't really explosive. On the contrary, if you can saturate hydrogen gas with oxygen gas without touching it off, a single spark could collapse a balloon almost instantly. Hydrogen gets a bad rap because of the Hindenburg, which actually caught fire due to the doping compounds on its skin. The hydrogen only aggravated the situation, but it actually took a while for the Hindenburg to burn, compared to an actual explosion (34 seconds compared to 50 milliseconds).


Bzzz thanks for playing! The correct anwser is: Hydrogen is explosive, because you have forgotten to factor heat into your equations! Hydrogen and Oxygen don't combine to form liquid water, they combine to form gasseous water! That's a ratio of 1:3, not 1:100000! Furthermore, you've forgotten that the gas constant of 22 mols per liter is at standard pressure/temperature! When you combine hydrogen and oxygen, lots of energy is released to make that steam expand! Heated air takes up more volume thatn cold air! This causes the outward explosion!

Well, we hope to see you next time on, "Are you smarter than an 11th grader?"


hmm I'll take PBS and their documentaries over the Myth busters any day.


Bzzzt, Experimental evidence trumps theory any day! Unless mitigating factors were called into question in PBS for the additional paint flammability, Mythbusters shows that there is no extra flammability, unless you raise concerns about their methodology! Remember kids, source credibility is an issue but science is built on evidence above all else!



Hope to see you next time!

Triaxx
2008-02-18, 07:58 PM
As long as we're talking lift, a Decanter of Endless Fire would provide more than enough heat to keep a ship a float on plain hot-air. The creation process simply requires the application of Energy Substitution during the creation.

seedjar
2008-02-19, 12:05 AM
The base spell for a decanter is control water. What's energy substitution supposed to do with that?
~Joe

The Demented One
2008-02-19, 12:10 AM
Planar Distortion Engine
A Planar Distortion Engine contains a small portal to the Far Realms, sealed within the innards of the engine. The engine's mechanisms channel the alien energies of the Far Realm to create a bubble of energy which distorts the normal laws of reality. Though there are several uses this could be put to, the most common is in airships, as the bubble of distorted reality bends the laws of physics enough for the airship to fly, supported by only the flow of raw power from the engine. Using a Planar Distortion Engine has been known to occasionally cause bizarre and unpredictable phenomena, adjudicated by the DM.

Moderate Conjuration, CL 11th. Craft Wondrous Item, plane shift. Cost and price left to the DM.

Fizban
2008-02-19, 02:33 AM
I'll pose another question as to the intent of the thread: are you looking for prices, in game/in rule justification, or just any old airship related ideas. Right now it sounds like "within the rules create a usable airship", which just doesn't work by itself. It's easy to just make something up using spell effects, but you'll never get the price to one usable without DM fiat. The more pseudo physics you use in combination with magic to lower the price, the more DM fiat you'll need to be allowed it. Generally it's best to just make everything up from scratch: that way you can explain and price it however you want.

For printed materials, let's take a look at the Arms and Equipment Guide. It gives you a Dirigible with a 5 ton cargo capacity for 35,000gp, or a Zeppelin with 10 tons for 60,000gp. The balloon isn't just paper thin either, and with a bit of magic your ship will be quite durable, if slow. I believe the Ebberon setting prices a full airship at anywhere from 100,000 (discount) to 200,000 gold pieces, but those will be larger than the balloon rigs. In Stormwrack and the AaEG magical accesories to grant a normal sailing ship flight cost upwards of 100,000gp. (Edit: okay there's none in Stormwrack, and the AaEG one costs 200k).

Generally, it seems that WoTC doesn't approve of flying ships for less than 100k, though the AaEG got away with 35k for a smaller one somehow. You may be able to set up some spells to get a ship working in the air, but committing them to item form will pretty much always cost at least that much, after taking into account the size you need to affect. Smaller "fighters" are possible for much less, but then you might as well just cast fly. Still, the idea of an enhanced galley with ornithopters (4,000gp each) dropping out of the hull is quite cool. (A hang glider's only 300gp, and faster, but you'll need some sort of magic to make it rise. Oddly enough, you could equip it with an adamantine ramming prow and have a pretty good suicide attack. I'm pretty sure they fixed that cargo detail in Stormwrack though).

The cheapest way is probably going to be building a gargantuan object with large wings, then permanency-ing animate objects on it. Colossal would require epic CL, and even this will take a lot. This is both good and bad: your entire ship goes down with one spell, but it's already at a high CL so it's hard to dispel. You could also look into really big effigies, but then again those cost just as much as a flat *large sum of gp* airship.

Woa, Soarwhales are increadibly cheap. 10,000gp for a youngling plus another 1,000gp to rear and train. That's a total of 11,000gp for a CR15 creature that has 467hp, and can fly carrying over 44,000lbs. I think that just about wins.

Thamir
2008-02-20, 12:53 AM
True but right now I am talking more about just plot, the fluff rather than the crunch, I don't know how a soarwhale is that much stupid unbalanced arms and equipment guide.

Talic
2008-02-20, 01:38 AM
You assume all of those things are true. In fact objects in D&D fly off in random directions without forces acting on them all the time - that's what the Fly spell does for a start.

Again magic provides the power. Without a creature capable of casting a fly spell on a living creature (not an object), that creature will not fly, except by the laws of physics.


The problem is that "magic" isn't a form of energy. If it was, it wouldn't work the way it does.

Each form of energy has its own properties and rules. For instance, sonic energy is really a form of rapid convection of heat. Vibrating molecules, and all that. Radiant energy can't work that way. It can transmit energy through a vaccuum, which convection and conduction cannot. How then, can you assume that magic does not have its own distinct properties?


Most obvious example: it is aerodynamically impossible for dragons to fly. Do they fly with magic? Then why can they fly in an antimagic field? And why do they have wings in the first place?
Yes, they fly with magic, however, it is not a spell or spell like ability. It is a supernatural special quality of locomotion, which is not suppressed by Anti-magic field.

Think of an electrical insulator, like rubber. Prevents the flow of electricity. With me so far? Think of certain things like supernatural special qualities, as insulated wires running through the rubber. Now, most electricity that hits that rubber doesn't go anywhere. It's stopped cold. However, electricity on this wire shoots right through, because the rubber isn't designed to prevent it.

There is a direct correlation here. Just because your understanding is flawed does not mean the concept is.

Talic
2008-02-20, 01:49 AM
You assume all of those things are true. In fact objects in D&D fly off in random directions without forces acting on them all the time - that's what the Fly spell does for a start.

Again magic provides the power. Without a creature capable of casting a fly spell on a living creature (not an object), that creature will not fly, except by the laws of physics.


The problem is that "magic" isn't a form of energy. If it was, it wouldn't work the way it does.

Each form of energy has its own properties and rules. For instance, sonic energy is really a form of rapid convection of heat. Vibrating molecules, and all that. Radiant energy can't work that way. It can transmit energy through a vaccuum, which convection and conduction cannot. How then, can you assume that magic does not have its own distinct properties?


Most obvious example: it is aerodynamically impossible for dragons to fly. Do they fly with magic? Then why can they fly in an antimagic field? And why do they have wings in the first place?
Yes, they fly with magic, however, it is not a spell or spell like ability. It is a supernatural special quality of locomotion, which is not suppressed by Anti-magic field.

Think of an electrical insulator, like rubber. Prevents the flow of electricity. With me so far? Think of certain things like supernatural special qualities, as insulated wires running through the rubber. Now, most electricity that hits that rubber doesn't go anywhere. It's stopped cold. However, electricity on this wire shoots right through, because the rubber isn't designed to prevent it.

There is a direct correlation here. Just because your understanding is flawed does not mean the concept is.

NEXT...

hmm I'll take PBS and their documentaries over the Myth busters any day.


Even when mythbusters is in agreement with the professional companies that rely on knowing the physical and chemical properties of the substances they use on a daily basis to keep their plants safe? Oh, and the government agencies that regulate the use of dangerous gases? Oh, and the collegiate studies that the agencies use to formulate that policy?

Yeah, I see how low-budget documentaries on non-profit organizations trumps all that. ALL of it. :smallamused:

One more study: research documents from University of Colorado, on THIS EXACT SUBJECT (http://spot.colorado.edu/~dziadeck/zf/LZ129fire2005jan12.pdf)

Oh, and that guy, after getting his PHd in the subject, spent 37 years in the Aeronautics and Rocketry field, before moving on to UC, and then a leadership position at Texas A&M. And he thoroughly debunks the spark, and the rocket fuel theory of the hull. Even if the hull was composed purely of the rocket fuel the theory is based on (Iron oxide and Aluminum powder, with a very large amount of the iron), it would take over 10 minutes to burn from end to end. The Hindenberg burned completely in 34 seconds. That's when there is a chemical source for oxygen in the fuel as well, a percholate agent, which, in the case of the Hindenberg paint, there was not.

But go ahead and believe the flawed findings of someone who paid $300 to get their show aired on PBS.

Paladin Latham
2008-02-20, 03:32 AM
There was a 3rd party soucebook called Airships a while back. It had stats for creating engines like regular Wondrous Items that propelled airships at up to 250mph. All it took was invested spell-slots per day (or corpses for the necro-engine).

Yakk
2008-02-20, 09:33 AM
Compared to true explosives, I don't consider burning hydrogen gas to be fast. Touching off LIQUID hydrogen would be explosive, since it has to grow to tremendously to vaporize. I think the distinction I make is that explosions have a concussive effect from rapidly expanding gases whereas gaseous hydrogen combines with oxygen to form water and thus shrinks away tremendously.

I really don't know why I bothered to do all of this math, but here it is:


PV = nRT
P = ~1 bar
V = 1 unit
n = 1 mole of H2, 0.5 of O2, ie 1.5
R = a constant
T = 300 kelvin

1 mole hydrogen + 1/2 mole of oxygen = 197.2 kJ released when it burns

Water has a specific heat capacity of about 1.864 kJ/kgK.

There are 18 grams in a mole of water...

So as a ballpark, we get:
197.2 kJ / (18 grams * 1.864 kJ/kg/K ) = +5 877.44397 kelvin

Ie, the water comes out hot. Say 6000 kelvin.

PV = nRT
P1V = 1.5*R*300
P2V = 1*R*6000
V/R = 1.5*R*300/P1
V/R = 1*R*6000/P2
450*R/P1 = R*6000/P2
450*P2 = 6000*P1
P2 = 13.333*P1

So, if my napkin math works, when you combust H2 and O2, you end up with a 13 times overpreassure ball of expanding 6000 degree kelvin water vapor.

6000 degrees seems the right ballpark -- H2 combustion is supposed to emit UV rays, which implies a high heat of combustion.

It is only after this ball of expanding water vapor cools off or goes away that you'd expect an underpressure situation.

Ie, 2H2+O2 = explosion The resulting H2O wants to take up about 13 times as much volume as the initial mix of H2 and O2 does.

Sofaking
2008-02-20, 09:42 AM
I haven't read all the responses so I don't know if this has been mentioned before but...

You could design a huge spider shaped ship and at the foot of each leg is an immovable rod. So the spider sort of crawls through the air by activating and deactivating the rods at the right times. Have it built by Drow with Gnome slaves and you have a great plot hook.

Yakk
2008-02-20, 10:41 AM
Backing up...

Is this a culture that contains lots of airships? Ie, an airship economy?

Or is it a one-off airship?

You said you want something false-techy rather than magicy...

Do you want it to be ship-shaped?

Thamir
2008-02-20, 04:23 PM
Backing up...

Is this a culture that contains lots of airships? Ie, an airship economy?

Or is it a one-off airship?

You said you want something false-techy rather than magicy...

Do you want it to be ship-shaped?

Yes it has lots of airships plus tribes of dwarf barbarians who ride soarwhales.

I'd say about 2 magic per 5 false tech 2:5

Yes ship shaped.

Citizen Joe
2008-02-20, 07:20 PM
I really don't know why I bothered to do all of this math, but here it is:


Ie, 2H2+O2 = explosion The resulting H2O wants to take up about 13 times as much volume as the initial mix of H2 and O2 does.

Well, what you are missing in your calculations is the conversion rate of hydrogen to steam (explosion rate) vs. the cooling rate of the steam. The higher the temperature differential the faster the cooling and thus underpressure situation.

Remember that what we are talking about is a sealed hydrogen rich environment being touched off by fire. Thus, assuming a total failure of the balloon skin (the balloon suddenly vanishes), we're looking at a oxygen mixture based on the square of the radius whereas the volume is based on the cube of the radius. Combine that with hydrogen's tendency to rise and you get a result quite different from a conventional explosive. I think the real danger comes from it burning invisibly so you don't realize until it is too late that you're on fire.

Anyway... in an attempt to end this, can we agree that hydrogen production in the quantities needed for mass air travel would be sufficiently anachronistic as to be unfeasible in a fantasy setting. Ditto for helium.

FlyMolo
2008-02-20, 07:49 PM
Calculations hard, hydrogen bad, Anachronistic *draconian summary over*
Hydrogen is a bad idea.

Steam power, generated with decanters of endless water and something which makes heat, means endless power. Immovable rods for thrust,(on big waterwheels, of course) and maybe lift. Vent the steam through nozzles for extra thrust and an anti-boarding weapons(very hot) AND a cloaking device (hide inside a steam cloud anyone?). And you could shoot things with it. Steam cannons, etc.

Triaxx
2008-02-20, 08:10 PM
Huh? Oh, knew there was something wrong. We use Create Water instead, since Control Water makes exactly zero sense. But it could work, just changing what's controlled to fire, instead of water.

D Knight
2008-02-20, 08:17 PM
ok have any of you try taking 2 mith tower sheilds medium have one enchanted with the winged ablity from DMG and enlarge object to make the thing really big and i mean BIG. from there you use a large onxy orb for control and glass steel for the windsheild. and there you go one air ship body ready to fly now all you have to do is add a weapon system and the floor plan of the inside if you want me to give more detailed how to PM me and i will get back to you as soon as posible.

seedjar
2008-02-20, 08:38 PM
Huh? Oh, knew there was something wrong. We use Create Water instead, since Control Water makes exactly zero sense. But it could work, just changing what's controlled to fire, instead of water.

Create Water has the same problem. Energy Substitution allows you to swap energy damage of one type to another. Create Water doesn't explicitly deal damage; particularly not energy damage. So an Energy Substitution'd Create Water would deal 0 damage of some other energy type, but still 0.
Conceptually, as well, it doesn't quite make sense. Water is a persistent object; as long as it doesn't evaporate or drain away or something, you can put it down, pick it up, leave it indefinitely. Fire is energetic and mercurial - once it's fuel is gone, so is the fire (fire from the elemental planes notwithstanding.) Create Water just doesn't seem like an appropriate base spell; consider the fire created by Produce Flame, also a level 1 spell. If I were a DM adjudicating your idea, I'd set the fire effect to be at least level 3. Flames powerful enough to lift a ship have got to be at least as strong as a Fireball.
~Joe

BRC
2008-02-20, 08:39 PM
Create Water has the same problem. Energy Substitution allows you to swap energy damage of one type to another. Create Water doesn't explicitly deal damage; particularly not energy damage. So an Energy Substitution'd Create Water would deal 0 damage of some other energy type.
Conceptually, as well, it doesn't quite make sense. Water is a persistent object; as long as it doesn't evaporate or drain away or something, you can put it down, pick it up, leave it indefinitely. Fire is energetic and mercurial - once it's fuel is gone, so is the fire (fire from the elemental planes notwithstanding.) Create Water just doesn't seem like an appropriate base spell; consider the fire created by Produce Flame, also a level 1 spell. If I were a DM adjudicating your idea, I'd set the fire effect to be at least level 3. Flames powerful enough to lift a ship have got to be at least as strong as a Fireball.
~Joe

Permanancied Wall of Flame

seedjar
2008-02-20, 08:41 PM
That sounds much more reasonable, but pricey.
~Joe

PS - Actually, to look at it... relatively affordable if your DM gives it to you at the standard price. I'd probably make a little adjustment myself given that the flames are being applied in a much less passive way than with a Wall, but so long as my players weren't trying to use it as some money-making scheme, I wouldn't object.

BRC
2008-02-20, 08:45 PM
That sounds much more reasonable, but pricey.
~Joe
Or the DM could just invent some magitech to run an airship, but apparently this one wants to do it by RAW.

Triaxx
2008-02-21, 08:57 AM
I guess I missed something in Energy Substitution's description. We've been treating it like it affected things like Create Water=Create Fire, or such.

Yakk
2008-02-21, 09:35 AM
Or the DM could just invent some magitech to run an airship, but apparently this one wants to do it by RAW.

Thamir, do you care if your airship engine is RAW? I see lots of RAW based proposals, but I don't see your actual request that it be by raw. :)

Thamir
2008-02-21, 04:13 PM
Anything is fine. Please the more the merrier. Essentially if it flies its fine!

Elrond
2008-02-27, 12:52 AM
if in doubt kick it :smallbiggrin:

Thamir
2008-02-27, 03:06 AM
Yeh big football (Aussie Rules)

ZeroNumerous
2008-02-27, 03:37 AM
Ok, I just searched through all the threads and apparently no one has mentioned this..

You need the following ingredients: A single arcane caster of at least 16th level preferably with 10 levels of Warweaver. A divine caster of any level. A fighter also of any level.

Mix one Animate Object with the ship. The ship becomes a colossal construct.
Add in a little Permanency.
Now have the Warweaver apply his Personal range spells through his Eldritch Tapestry. Select the spell Overland Flight. This grants a 40ft fly speed at range: Personal for 1/hour level. Lightly season with Extend Spell
Season to taste with turrets of fireball. Serves 6.

This idea creates a ship that can fly under it's own power for at least 16 hours. (32 if Extended) Not only that, the ship can fly in ways that defy the conventional laws of physics. Your ship flies at 200 mph in a straight line? Interesting. Mine levitates 40ft up, then instantly makes a 90 degree turn on a dime. Make it discus shaped and you have D&D's first flying saucer.

Talic
2008-02-27, 04:22 AM
Ok, I just searched through all the threads and apparently no one has mentioned this..

You need the following ingredients: A single arcane caster of at least 16th level preferably with 10 levels of Warweaver. A divine caster of any level. A fighter also of any level.

Mix one Animate Object with the ship. The ship becomes a colossal construct.
Add in a little Permanency.
Now have the Warweaver apply his Personal range spells through his Eldritch Tapestry. Select the spell Overland Flight. This grants a 40ft fly speed at range: Personal for 1/hour level. Lightly season with Extend Spell
Season to taste with turrets of fireball. Serves 6.

This idea creates a ship that can fly under it's own power for at least 16 hours. (32 if Extended) Not only that, the ship can fly in ways that defy the conventional laws of physics. Your ship flies at 200 mph in a straight line? Interesting. Mine levitates 40ft up, then instantly makes a 90 degree turn on a dime. Make it discus shaped and you have D&D's first flying saucer.

Nice. Few issues, though.

Animate Objects limits your ship size to gargantuan, unless you're a level 32 caster.

Overland flight is good maneuverability, not perfect. Further, weight would limit the speed of the vessel, based on the strength of the animated ship.
Also, the ship would control the flight, not the pilot. Further, Animate objects only lists one form of control. Attack. Which means the boat may spend a lot of time chasing flocks of birds.

Finally, the caster is essentially married to the boat. Good option for an individual vessel, with other types of vessels in the world, but not something that would be common for ship design.

Ideally, make the hull insanely durable. Low speed will make the ship vulnerable, though this would be an interesting combination for a warship. Warweaver could get sudden bursts of speed by throwing a Fly spell through the weave when it mattered.

40 ft fly = 80 ft/round =800 ft/minute = 48,000 ft/hr = 9 miles an hour. Fly spell is about 13. Assuming it could be pacified down, it'd make a good transport, otherwise, it'd make a decent flagship/command ship with lighter, faster ships as an escort. For defense, I'd recommend something with more kick than fireball, though. Obscuring mist for hiding, with occasional Body of the Sun, some fireballs, and scorching ray for point defense.

Thamir
2008-02-27, 04:57 AM
I like the idea of an airship chasing a flock of birds he he. I am having many sorts of airships one of which is part of a kinda oriental culture which is held up by an ancestor spirit of the pilot which also turns a giant waterwheel for thurst. I think its cool.

ronnyfire
2008-02-27, 05:53 AM
Ok, I just searched through all the threads and apparently no one has mentioned this..

You need the following ingredients: A single arcane caster of at least 16th level preferably with 10 levels of Warweaver. A divine caster of any level. A fighter also of any level.

Mix one Animate Object with the ship. The ship becomes a colossal construct.
Add in a little Permanency.
Now have the Warweaver apply his Personal range spells through his Eldritch Tapestry. Select the spell Overland Flight. This grants a 40ft fly speed at range: Personal for 1/hour level. Lightly season with Extend Spell
Season to taste with turrets of fireball. Serves 6.

This idea creates a ship that can fly under it's own power for at least 16 hours. (32 if Extended) Not only that, the ship can fly in ways that defy the conventional laws of physics. Your ship flies at 200 mph in a straight line? Interesting. Mine levitates 40ft up, then instantly makes a 90 degree turn on a dime. Make it discus shaped and you have D&D's first flying saucer.


sorry, just no xD

need to make personal ranged spells longer range for war weaver to work with it (they work with any NON personal range spell)

there are was to do this, but they are slightly painful.