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jseah
2009-12-21, 10:01 AM
EDIT: Thank you for your suggestions:

The constraints I'm looking at are items of CL9 or less plus spells above CL9 are rare. (and so will only get a few tens of them in a year regardless of how much you pay)

Gold piece constraint is somewhere around 1-4 million gp military spending a year. Although I would like to not be constrained to building one ship a year, so exceedingly expensive set ups are problematic.

Trap rules can be considered to not exist.

************************************************** ***

Sorry to post a new thread when there's an Airship thread and a Magic as Tech thread, but I couldn't find the Magic as Tech thread in the last three pages and the Airship thread wasn't appropriate.

First off, I am trying to design an airship using D&D3.5 SRD rules and special materials only. Eberron elemental rings were considered but are impossible to adjudicate.
Stronghold Builder's Guide for making flying buildings is too expensive.

The game has a houserule about magical locations that make it possible to exploit permanent spells to achieve what I need.

Location
- Any object that is larger than 200ftx200ft (height doesn't matter) is considered a location.
--- Stationary effects casted while in that location will move relative to that location
--- it is pinned to the location that it was casted from, not casted into
- Any volume that is completely enclosed is considered one location
--- Moving the enclosure moves all stationary effects casted while in that location
--- Opening/closing the volume fuses that location to the outside one

I currently have two designs.

Giant hot air balloon (enough to fit the location rules) using permanent Wall of Fire as a heat source.
- Can anyone estimate the energy requirements for a hot air balloon? I'm trying to find out if Wall of Fire outputs enough energy for this to work. (It gives out gigawatts but it's really really huge, so excessive heat loss could kill the plan)


Permanent Gust of Wind in a box (to trap it via location rules) serves as an engine.
- This is the method that will surely work, but is insanely expensive and somehow ends up as VTOL powered flight


Any comments, new ideas and input welcome.

Yuki Akuma
2009-12-21, 10:04 AM
Make it a sailing ship with a bound fire or air elemental to provide lift.

Or just buy Eberron.

jseah
2009-12-21, 10:10 AM
First off, I am trying to design an airship using D&D3.5 SRD rules and special materials only. Eberron elemental rings were considered but are impossible to adjudicate.
Stronghold Builder's Guide for making flying buildings is too expensive.

Make it a sailing ship with a bound fire or air elemental to provide lift.

Or just buy Eberron.
Besides, Fire/Air elementals pose too large a risk.

Too hard to obtain, and if they go beserk, someone might get killed.

I'm talking Magic as Technology. Any risk that isn't negligible is too large a risk.

EDIT: plus automation is a key feature. Elementals might need a handler and specialized jobs are exactly what I'm trying to replace.

Mark Hall
2009-12-21, 10:31 AM
Actually, this is somewhat similar to what they did in Earthdawn. Airships flew because of Elemental Air... not an Air Elemental, but they possessed fragments of absolutely pure elements, and with a bit of elemental air, things float. Put enough of it into a ship, and large things float. You still need some specialized jobs... the helmsman has to know different things, and there are air miners (and earth miners, water miners, and fire minors who go out into the fiery sea)... but most sailors aren't far different from the sailors on seas of water.

In terms you're talking about, however, I would say wall of fire and Gust of Wind would be just fine. While I won't try to work out the energy output, they are quite big, and the fires that run modern hot-air balloons are relatively small... you could get a decent sized balloon up with an always-on hot wall of fire, especially if you have a bag that's tight enough. GoW should also work... the gondola is effectively weightless, though not frictionless or inertialess. A constant GoW effect will, eventually, overcome inertia until it reaches equilibrium with friction. I say that a reasonable speed for them would be equal to a medium or small flying creature under the effect of a GOW (http://www.d20srd.org/srd/spells/gustOfWind.htm).... 5-60 per round. You can walk as a fast as an airship in this case... but the airship will keep going, long after you've tired, and it ignores hills and the like.

Slayn82
2009-12-21, 10:55 AM
Good to see you again, Jseah. Well, our old thread is just inactive in the last 10 days, it could be put back up as long as its less than 45 days, even if its beyond page 3.

Now, you could go for getting a sea ship and ataching to it a big Pot-like structure, and cast a FIREWALL into it. The description of the Wall of Fire spell says:

Opaque sheet of flame up to 20 ft. long/level or a ring of fire with a radius of up to 5 ft. per two levels; either form 20 ft. high .

So, you could perfectly cast a FIREWALL that is a sheet of flame 5ft. long, since the spell just have an upper limit, not a lesser size limit. Or make a more compact Ring.

Then you will just need a large balloon to lift your ship. My recomendation is that you settle with something with the lesser size possible. Also, be carefull about damages to the balloon.

Notice that by putting the FIREWALL into a pot, you can take advantage of the Fourth and fifth itens of the Houserules as presented:
"---Any volume that is completely enclosed is considered one location

--- Moving the enclosure moves all stationary effects casted while in that location"

jseah
2009-12-21, 01:46 PM
Mark Hall and Slayn:
Thank you for your response. The suggestion about using elemental air is a good one but there isn't a listed stat for such things.
While I'm the GM and can simply rule 0 it in, I would like not to. Zero weight structural materials pose problems of their own.

I did some research and ran some calculations:

GoW generates a 50 mph wind, which is 73.3 ft per second.
It's a line, so that's 25ft area, moving 51.9 cubic meters per second.
The wind therefore has a momentum of 1391 kg m per s. Reflecting the wind generates twice that amount of force and can be done with an appropriate drive design.
One Gust of Wind drive will generate 2783 N, and can lift approximately 283kg.

I'm not sure how much Wall of Fire will lift, but balloons lift around 0.3 kg per cu m. To generate 283 kg of lift, you need a balloon volume of 943 and 1/3 cu m.
Our current balloons have around 2831.7 cu m of volume (100 000 cu ft).
Going by my calculation in the other thread, 2800 sq ft Wall of Fire generates 1.37GW. CL8 wall of fire is 20ft radius, 20ft high = 25 132 sq ft, giving 12.3GW of heat. (looks like circular wall of fire is actually larger than the flat version)
Wall of Fire is a heat source that generates approximately 4000 times the heat output of our burners, wikipedia puts balloon flamers at around 3MW of heat for a 2831.7 cu m balloon. Wall of Fire heated blimps can be some 200 to 400 times larger than those if power scales to volume linearly (and after a 10 times drop in efficiency). A 40 million cu ft blimp will lift 340 tons before structure.
Wall of Fire will lift more per casting that Gust of Wind.

Wall of Fire costs 10 880 gp per permanent casting
Gust of Wind costs 8 110 gp per permanent casting
Wall of Fire still lifts significantly more (a thousand times more in fact).

However, size is a problem. Blimps are HUGE. The above 40 million cu ft blimp is the size of a sphere just over 1km in radius.
In comparison, the Hidenburg-class of zeppelins, the largest we ever built, were only 7.1 million cu ft. The projected 40 million cu ft blimp is 5.6 times larger.

Obviously, Gust of Wind engines will be used for the balloons to thrust. Or flaps to exhaust air. (the wall of fire heats more air than we need I think)

EDIT:
Furthermore, the blimp will need some pretty strong cloth if you don't want it damaged. I suggest casting Hardening (artificer 6th level infusion) to give it DR. One casting affects 110 cu ft at minimum CL, which is rather alot for cloth.

jseah
2009-12-21, 01:58 PM
Just thought of something crazy. Is there an item that lets you use Floating Disk?

It stays level to the ground right? What happens if the ground is attached to the disk? XD

Prime32
2009-12-21, 02:15 PM
Get some flying constructs/undead to move it around for you. Preferably the kind that doesn't require wings, so that you can put them inside the airship where they won't be vulnerable to attack.

Decanters of endless water are also useful, either as jet engines or to turn water wheels (though if you want to turn something it's probably cheaper to put some skeletons in giant hamster wheels and order them to run without stopping).

Don't forget the utility of reverse gravity and feather fall - the former could be used for loading, and contingent versions of the latter should be set around the ship to activate if the power source fails.


The simplest way to get an airship, though, is just to ride around inside a Colossal undead (like a zombie dragon).

jseah
2009-12-21, 02:35 PM
I'd hesitate to use constructs. They tend not to lift enough unless you get super high strength ones.

Right, Decanters.
If you use Decanters to provide water for wall of fire to evapourate, you could make a steam rocket out of it.

Bob
2009-12-21, 02:42 PM
summon a herd of celestial balean whales and cast fly.

Radar
2009-12-21, 02:58 PM
Question to consider:
Would Reverse Gravity cast inside an airship be able to lift the ship, if more the half of it's mass was affected by the spell?
My answer would be yes, since the spells don't follow the 3rd law of dynamics anyway. For example Gust of Wind doesn't hit the wizard with a cumulative effect from all of the targets, right? Or any sort of Telekinesis doesn't throw the poor caster around as he manouvers some heavy object.

math: if one uses lead as the balast, it' 321kg per cubic foot. One gets 150 cubic feet at the minimal caster level. That gives 48 167 kg of lift (note, that is 48 tones in addition to all the balast). It's not included in the permanecy table, but an auto-reseting trap would cost 52 500 gp and 4200 XP so 73 000 gp if one outsources production. It's a lot less then Wall of Fire, but still enough for a reasonable craft.

An auto-reseting trap of Wall of Fire would cost 19 467 gp in comparison. It has the advantage of not being vulnurable to a single dispell and one trap can keep quite a few Walls of Fire going, if one desires a world-sized zeppelin for some reason. Would be usefull for a faster liftoff of a regular baloon. Better yet: you can use Sonorous Hum (AFIK a 3rd level spell, that removes the need of concentrating on a spell, thus keeping the Wall of Fire as long, as it lasts itself) trap in conjunction with Wall of Fire traps, to fuel any number of baloons. A baloon would just have to have a permanent (again, not in the table, so your choice) or a trap of Sonorous Hum and be given one shot from a Wall of Fire trap located at the airport. This cuts you down to 10 429 gp per baloon (for Sonorous Hum trap - might be a lot less with permanency) and a Wall of Fire trap in every airport. This solutions is a bit safer then permanent Wall of Fire spells, since one doesn't have to constantly watch the everburning spell located under a big piece of cloth.

While Reverse Gravity would be a significantly more expensive spell, it gives much more reliability and versatility on craft's design. Essentialy, the spell should cover about half of craft's mass, with movable lead blocks being put in or out, to gain desired upward or downward acceleration. It could move horizontally and vertically using any other engine of course. The most important advantage is the lack of a giant baloon, which gives a potentially much higher speed and durability, so high class warships, would rather use this design.

jseah
2009-12-21, 03:02 PM
summon a herd of celestial balean whales and cast fly.
How long could that last? Airships need to stay afloat for hours at least. A few days to get the best mileage out of them.

That said, Decanter produces 22.7 liters of water per second.

To boil 1g of water from 25*C = 2571 J
To boil 22.7 kg of water from 25*C = 58 440 kJ

Therefore, to boil the entire output of the Decanter takes 58.44 MW. Easily done by wall of fire.
According to wikipedia, steam takes up ~1600 times the volume of water. Generating a pressure of some 1600 atmospheres if you give it no space to expand.
The steam rocket is viable.

Is there anyone who can make the calculations for a rocket like that?

jseah
2009-12-21, 03:04 PM
Well, I'm not using trap rules here. Those tend to be... kinda broken. As I'm sure tippyverse people have found out.

Reverse Gravity is a nice idea, but requires insanely high levels.

DabblerWizard
2009-12-21, 03:08 PM
I just wanted to mention, that Magical Airships remind me of Final Fantasy 2/4. Good times. :smallsmile:

Mando Knight
2009-12-21, 03:11 PM
Any risk that isn't negligible is too large a risk.

There will always be risks involved when creating flying machines.

jseah
2009-12-21, 03:18 PM
There will always be risks involved when creating flying machines.
Well, ok, perhaps I wasn't clear enough.

Depending on a capricious elemental or undead creature for the operation of such a ship isn't advisable when technological alternatives can provide far higher lift.

You can't eliminate risk, but you can reduce it.

Johel
2009-12-21, 04:00 PM
Giant hot air balloon (enough to fit the location rules) using permanent Wall of Fire as a heat source.
- Can anyone estimate the energy requirements for a hot air balloon? I'm trying to find out if Wall of Fire outputs enough energy for this to work. (It gives out gigawatts but it's really really huge, so excessive heat loss could kill the plan)
(...)

Any comments, new ideas and input welcome.

Meow !! :smallsmile:
Meow ? :smallconfused:
Meow !! :smalleek:
*SPLOTCH !!* (http://www.youtube.com/watch?v=kqV0Efo-qdQ)

Now, seriously, unless your party LOVES to make complex physic calculation for little to no RP gain, just hand wave it !!

If you don't want to hand wave it :
The initial lift :
Hot Air Balloon (http://en.wikipedia.org/wiki/Hot_air_balloon)
Dry air heated to 99 C can produce a lift of 0.9486 kg/m
So, to lift 1.000 kg, you need to heat a volume of 1.054 m.
Let's make it 1.500 m, as a security measure, shall we ?
That's 15m x 10m x 10m. Yeah, I don't like sphere and you can get that rectangle by using a light metallic superstructure.
Now, I'm no physicist and won't indulge in catgirl genocide but I guess a permanent Wall of Fire can heat a fairly large volume of air at 99C pretty quick.

The actual thing :
Flame (http://en.wikipedia.org/wiki/Flame)
Flame temperatures of common items include a blow torch - which can burn usually up to around 1,600 C, a candle at 1,400 C,[5] a propane torch at 1,995 C, or a much hotter oxyacetylene combustion at 3,000 C. Cyanogen produces an even hotter flame with a temperature of over 4,525 C (8,177 F) when it burns in oxygen.[6]

Your average CL12 permanent Wall of Fire is a 72 m long furnace capable of instantly toasting most humans trying to get through. The flames spread 6m high and are still at full heat at that point. It also spread heat waves up to 6 m away in a direction chosen by you and these heat waves are themselves enough to severly burn most humans. Since a candle isn't exactly going to kill a human in a matter of second, we can guess the Wall of Fire is at least 1.400C and that's a minimum.

What does it mean ? It means a single CL12 Wall of Fire can heat a maximum volume of 2.592 m of air at any given time. Much more than what we need to take off. However, said air won't instantly reach 99C, unless Wall of Fire has a VEEEEERY powerful energy generation capacity. Air needs to be heated progressively and to achieve that, I propose the alembic.

The Alembic :
a maze-like network of pipes that runs above the length of the Wall of fire. As the air is heated, it tries to escape by going up, so the pipes have to be inclined slightly, so that the air will just run along. Being kept above the fire for a certain time, given air particles will eventually reach a very high temperature before reaching the end of the pipe network and be released among the large, slowly cooling, volume of air inside the balloon. The sudden addition of overheated air will raise the overall temperature.

All you have to know is the proper length of pipe needed for air to reach a temperature higher than 99C. 72m ? 144m ? more ? less ? This can be done by your character using trial and error and really, it shouldn't be a concern, unless you're going to make a very detailed accounting of the costs.
You also need to make the pipes in a material that won't melt after a few hours of fly... Tungsten ?

So... I didn't answer your question about the energy output of the Wall of Fire but damn... just go with "enough to lift my airship". If your DM is ok with it, go for the megalomaniac version : a 5ft Wall of Fire produces as much energy as a Burner (http://en.wikipedia.org/wiki/Hot_air_balloon#Burner).

jseah
2009-12-21, 04:12 PM
All right, I'm running the calculations for the rocket.

Let's use a "simple" De Laval nozzle and take a 1D approximation since wikipedia has done the hard work for me.
Equation can be found at this place: http://en.wikipedia.org/wiki/De_Laval_nozzle

*****************************************

Worst Case Assumptions:
1. Superheated water evapourating just before the nozzle generates the high pressure gas. And that the nozzle is designed to work for that amount of steam.
2. Steam is an ideal gas (way way off)
3. Temperature of inlet gas is 200*C (easily achievable by the wall of fire boiler)
--- k = 1.310 according to wikipedia
4. Amount of water exiting is 22.7 liters per second (1 Decanter's worth)
5. The nozzle is tuned to give 1 atm exhaust pressure (for best operation at ground level)
6. The nozzle is tuned to give 20 atm inlet pressure (medium pressure boiler)

Exhaust velocity: 783 m s-1
Exhaust momentum: 17 772 kg m s-1
Maximum lift: 1 811 kg

*****************************************

Best Case Assumptions:
6. The nozzle is tuned to give 200 atm inlet pressure (supercritical boiler)
4. Amount of water exiting is 2270 liters per second (100 Decanter's worth, the circular wall of fire can boil ~139 Decanters worth given 10% efficiency)

Exhaust velocity: 928 m s-1
Exhaust momentum: 2 108 255 kg m s-1
Maximum lift: 214 909 kg

*****************************************

Observations:
Complex system involving a rocket nozzle. Most likely falls somewhere between the worst and best case scenarios.

Very costly, as the nozzle will mostly likely be made of Adamantine with Hardening cast and a Quitessence layer. Either that or it's a Wall of Force.
Plus that 100 Decanter + wall of fire boiler costs just over 910k gp.

The good bit is that the rocket can break the sound barrier if your ship can survive that. VTOL flight huh...

jseah
2009-12-21, 04:18 PM
If you don't want to hand wave it :
The initial lift :
Hot Air Balloon (http://en.wikipedia.org/wiki/Hot_air_balloon)
Dry air heated to 99 C can produce a lift of 0.9486 kg/m
So, to lift 1.000 kg, you need to heat a volume of 1.054 m.
Let's make it 1.500 m, as a security measure, shall we ?
That's 15m x 10m x 10m. Yeah, I don't like sphere and you can get that rectangle by using a light metallic superstructure.
Now, I'm no physicist and won't indulge in catgirl genocide but I guess a permanent Wall of Fire can heat a fairly large volume of air at 99C pretty quick.

The actual thing :
Flame (http://en.wikipedia.org/wiki/Flame)
Flame temperatures of common items include a blow torch - which can burn usually up to around 1,600 C, a candle at 1,400 C,[5] a propane torch at 1,995 C, or a much hotter oxyacetylene combustion at 3,000 C. Cyanogen produces an even hotter flame with a temperature of over 4,525 C (8,177 F) when it burns in oxygen.[6]

Your average CL12 permanent Wall of Fire is a 72 m long furnace capable of instantly toasting most humans trying to get through. The flames spread 6m high and are still at full heat at that point. It also spread heat waves up to 6 m away in a direction chosen by you and these heat waves are themselves enough to severly burn most humans. Since a candle isn't exactly going to kill a human in a matter of second, we can guess the Wall of Fire is at least 1.400C and that's a minimum.

What does it mean ? It means a single CL12 Wall of Fire can heat a maximum volume of 2.592 m of air at any given time. Much more than what we need to take off. However, said air won't instantly reach 99C, unless Wall of Fire has a VEEEEERY powerful energy generation capacity. Air needs to be heated progressively and to achieve that, I propose the alembic.

The Alembic :
a maze-like network of pipes that runs above the length of the Wall of fire. As the air is heated, it tries to escape by going up, so the pipes have to be inclined slightly, so that the air will just run along. Being kept above the fire for a certain time, given air particles will eventually reach a very high temperature before reaching the end of the pipe network and be released among the large, slowly cooling, volume of air inside the balloon. The sudden addition of overheated air will raise the overall temperature.

All you have to know is the proper length of pipe needed for air to reach a temperature higher than 99C. 72m ? 144m ? more ? less ? This can be done by your character using trial and error and really, it shouldn't be a concern, unless you're going to make a very detailed accounting of the costs.
You also need to make the pipes in a material that won't melt after a few hours of fly... Tungsten ?
So... I didn't answer your question about the energy output of the Wall of Fire but damn... just go with "enough to lift my airship". If your DM is ok with it, go for the megalomaniac version : a 5ft Wall of Fire produces as much energy as a Burner (http://en.wikipedia.org/wiki/Hot_air_balloon#Burner).
Well, I'm the DM. And I think that the calculation is handwavey enough.
EDIT: I also do this for kicks. XD

The thing here is that I'm trying to decide what would be the method of airship flight that the magic as technology country will be investigating as part of my setting that I'm building.

The 5x5ft section of firewall does output more than the 3MW burner. It's about 10MW.

The point is that simple hot-air balloons of small size cannot carry enough payload to work in a military field unless used for recon. I need something that will lift at least 10 tons.

Lysander
2009-12-21, 04:38 PM
Instead of hot air, why not use vacuum? Create cubes made of Walls of Force (contained in something like a thin steel cube to "trap" them) and then teleport the air out of them. Vacuum will generate more lift than hot air so you can devote less of the ship's area to lift and more towards storage/living quarters.

This hasn't been done in real life because it's hard to create a giant contained vacuum that won't implode under atmospheric pressure. But with walls of force the sky's the limit (no pun intended).

jseah
2009-12-21, 04:42 PM
Yeah... the wall of force cube huh.

The problem with the wall of force cube is that I'm unsure if air pressure even works on it. Even if the weight of the air displaced was normal, it's not clear if the wall of force will communicate the bouyancy force to the ship.

Mando Knight
2009-12-21, 04:52 PM
This hasn't been done in real life because it's hard to create a giant contained vacuum that won't implode under atmospheric pressure.
Actually, it's mostly because it's hard to create contained vacuum period, much less one where the pressure difference is sufficient to lift the equipment used to create it.

I'd just stop and say "a wizard did it (http://tvtropes.org/pmwiki/pmwiki.php/Main/AWizardDidIt)." You don't want me to start running the calculations. It isn't going to be pretty, and it isn't going to be practical, either.

jseah
2009-12-21, 05:07 PM
We have a depressurizer in the form of a Gust of Wind spell made permanent. Which weighs nothing.

How a constant air flow of 50mph would work to create vacuum, I've no idea.

Storm Bringer
2009-12-21, 05:11 PM
i think it may be easier to craft a custom spell to do the job than to force existing spells into service in a sub-optimal way.

I mean, I can imagine a simple, effective, magical jet engine without too much difficulty, and discribe it in general terms, but making it work with existing spells would be rather harder and more expensive than making a single custom spell to do the job.

maybe instead of spells, go with a item-crafting approach? some form of souped up leviation spells.

also, what sort of use do you see these airships being used for?

jseah
2009-12-21, 05:26 PM
I first intended to use the airships as a military battle platform, but quickly decided that that would require weird things like zero weight construction materials.

So I'm currently trying to make a bomber. A bit like how the zeppelin was used or Bomber Command. Just sort of a general military application.

In particular, common people in my setting are between level 4 to 7 in a PC class. 9th level PCs are rare and it doesn't get higher than that. Any higher than 9 CL effects have to be gotten from an extraplanar source.

Then again, it's a fully explored and charted world, with over 100 million population, so anything less than 9 CL is easily affordable. GDP of countries range from 10 million to 1 billion gp. Remember that you can't really get more than 1 or 2% out of it for war spending on this.
Artifacts also don't exist.

Gunpowder doesn't exist or hasn't been discovered btw.

Lysander
2009-12-21, 05:29 PM
Actually, here's the simplest airship. A Flying Carpet nailed flat to a board with a Well of Many Worlds stitched onto it. Keep closing and opening portals until it links to a place you like before stitching the well to the carpet to keep that portal open forever.

Then you can build a castle on the other side of the portal and keep your passengers and cargo there until the carpet arrives at it's destination.

Just curious, what's your price range?

Storm Bringer
2009-12-21, 05:43 PM
ok.

I;m no expert at either Real life physics or dnd magic rules, but I think it would be possible to build a jet engine using dnd magic fairly easily. all you need are three things:

a heat soruce (a magical fire of some kind)
a method of darwing air into the engine (some variant on gust of wind, mayhaps)
A non magical casing for the fire, to control the flow (could be made of steel or whatever wouldn't be damaged by the heat)

the gust of wind forces the air into contact with the fire, which heats it, making it expand. as air is being forced in one end of the casing, the air must move the other way, creating thrust.

it's a simple ramjet, in principle, but using magic to overcome the normal problems with ramjets. You might want to add some form of throttle to it, but depending on how you build the casing, and how hot you can get the air, you could get quite a lot of thrust out of somthing like this.

what spells to do it with and what actaul thrust they'd make, i don't know.

as for making a bomber:

what do you intend to use for bombs? if gunpowder is a no-no, then i can't think of any pratical munitions you could drop form one, save alchemists fire. to be honest, the recon and logicistic abilites of a small airship would likey be more useful than it;s bombing payload. the ability to see a ground armys movments form three days march away, and the ability to resupply a seiged castle with relative impunity, would be far more useful than pouring amchemists fire over a batlle line.

Johel
2009-12-21, 05:50 PM
The 5x5ft section of firewall does output more than the 3MW burner. It's about 10MW.

The point is that simple hot-air balloons of small size cannot carry enough payload to work in a military field unless used for recon. I need something that will lift at least 10 tons.

Well... You have your answer, then :
Build a very large airship, with hundred of hot-air balloons. :smallsmile:

Worst case, the balloons are destroyed and the airship goes splat.
Even if the airship crash in the ocean, that won't extinguish the permanent Wall of Fire for good. Just put it to sleep. Hire a wizard to recover the rail on which the spell was cast (Water Breathing + Resist Energy + Shrink Item + Teleport) and you'll just have to reassemble the airship, whose raw materials won't be that expansive.

Jack_Simth
2009-12-21, 06:33 PM
what do you intend to use for bombs? if gunpowder is a no-no, then i can't think of any pratical munitions you could drop form one, save alchemists fire. to be honest, the recon and logicistic abilites of a small airship would likey be more useful than it;s bombing payload. the ability to see a ground armys movments form three days march away, and the ability to resupply a seiged castle with relative impunity, would be far more useful than pouring amchemists fire over a batlle line.
Check the falling object rules, such as they are. Drop a bunch of ten pound bowling balls from a thousand feet up on top of someone, and they're pretty much dead unless the DM house-rules (technically a house-rule, anyway - more like filling in something for an area where the rules are simply silent, which is a big part of why you have a DM) in some dodging ability for when you do that.

As for ways to do it:
Flying Carpet + Portable Hole. Passengers will need Bottles of Air, Necklaces of Adaptation, or similar. No weight limit, no house-rules or DM adjucation needed.

Steam Jets:
Decanter of Endless Water (pick a number of them based on your thrust needs) into iron pipes, which run around a Wall of Fire. Water evaporates in the pipes, blasts out in whatever direction you set it up for. Turn the water off, you lose thrust. Water is controlled by the command-words for the Decanters, and can be made directional. Most things take half-damage from fire, and as iron has Hardness-10, that 2d4 damage from being within ten feet of the "business end" of the Wall of Fire will never breach hardness... so long as you're not running the pipes THROUGH the wall of fire (but at caster level 9 on the Wall of Fire, even that's not a problem - it caps at 21 points of damage, 50% round down for attacking an object means it caps at 10... and hardness applies to Fire, so iron pipes don't melt strictly by the book - and IC, you can say that the water in the pipes keeps them from going above critical temperatures - might explode, though, check your pressure, and makes for some great "research" background stories and investigations). Bonus: Circle Focused Outwards, most people will NOT be charging the side of your warship, even though most people will think that way.

Hot Air Balloon: Sufficiently covered, I think. Wall of Fire, focused inward, in a light container (almost any material will do, really, as the big thing is keeping it contained) with a big balloon over it. Gust of Wind, with some vanes to vector the thrust, for steering.

Levitate Trap: The simple Sor/Wiz-2 Levitate spell can provide lift for up to 100 pounds per caster level. A trap of it that's pushing an object which the trap "just happens" to be tied to gives you continuous lift of however much weight you want. Now you just need some way to steer.

Heat Metal Trap: A more readily controllable version of the Wall of Fire jet engine: On rounds 3-5 of the Heat Metal cycle, the object heated is "searing". A continuing repeating trap can heat the same metal over and over again, so it's constantly "searing". Run water from a Decanter of Endless Water through your pipes (and your pipes can weigh up to 25 pounds per caster level - basic copper tubing is actually surprisingly light) and you've got your steam jet again. The Heat Metal spell doesn't actually melt the target object, so you're golden, just need to direct thrust (and make sure you can get enough of it...).

Reverse Gravity Trap: Variation on the Levitate trap. Put most of the mass of the structure inside the area of Reverse Gravity, and it falls upwards. You can control vertical acceleration (not speed, acceleration...) by shifting mass in and out of the reverse gravity well, but you'll still need something for horizontal thrust. Maybe secondary containers that you rotate sideways?

erikun
2009-12-21, 06:47 PM
Does it need to be an airship? Because sitting inside a spherical container with Telekinetic Sphere (http://www.d20srd.org/srd/spells/telekineticSphere.htm), persist/permanent as needed, will end up nearly indestructable. Toss Prismatic Sphere on top of it as needed. The biggest problem is the slow movement speed.

Ormur
2009-12-21, 06:59 PM
Wouldn't sorcerers be the best bombs. You just fly the ship 600 feet high and have them cast fireballs through small openings. If you only have characters up to level 9 and the SRD I think it would be a good choice. If it's a strategic bomber you can kill most commoners and low level soldiers with them and they can set flammable medieval cities on fire. Blasting may be suboptimal in normal combat but with bombers you'll want to kill/destroy a lot of people/things from a distance without having to finish the job by actually going down for the coup de grace.

jseah
2009-12-21, 07:50 PM
Thank you for your suggestions:

The constraints I'm looking at are items of CL9 or less (and even CL9 is stretching it, only CL7 items are really common) and that spells above CL9 are rare. (will only get a few tens of them in a year regardless of how much you pay, no one has the CL to cast such spells except from a scroll)

Gold piece constraint is somewhere around a few million gp military spending a year. Although I would like to not be constrained to building one ship a year, so exceedingly expensive set ups are problematic. A ship design costing less than 100k would be ideal.

FYI, the opponent country doesn't have these technologies. They're a "normal" pseudo-medieval kingdom. For a certain value of normal that is.
They're lacking in tech, but they outnumber the tech country by over a hundred times in population and have at least ten times the gp to spend.

So enemy flying machines aren't going to be around, but anything flying under 1000ft will meet with significant resistance from ground forces using Fly. (casters aren't exactly rare in this setting)

****************************************

As for what bombs to use, I was intending to either use alchemist fire (they're cheap if you have millions of gp) or alternative warfare.

The war isn't bound by Geneva Conventions. It's an anything-goes war, and so I thought up a few more devious things, like mummy rot dust to cause an epidemic incurable by mundane means and eat enemy's cleric spells.

Or 7th level military spellcasters using fireball also works. Thanks for the idea, I'll use it. Say... call it a low level strafe, since 600ft puts you in range of enemy forces scrambling fly spells.

Alchemist fire and oil work exceedingly well if you can afford the weight. Oil burns for a long time, with alchemist fire as an igniter. If you can drop a few tons of incendiary bombs, you can attempt to start a firestorm in the mostly wood cities. Which would burn down huge swaths of... practically everything.
- Happened in WWII, the fires were basically impossible to put out, with the heat from the fire bringing the air above the flash point of most objects.

Another one I'm tossing around is a detachable frame and casting wall of stone on it. Then detach the frame and watch it fall.

Ideas here are also welcome, btw.

****************************************

Balloons
Defense of the craft is important. Anyone competent in magic can cast fly, so you have to weigh the fact that you'll meet significant flyer resistance at low altitudes.

Balloons are too large a target and don't have enough armour, hence me trying to find either a heavy-lift method (to carry lots of armour and ballistae) or a fast moving propulsion system (strafe them and they won't have time to engage you)
A way to use vacuum (through massively reinforcing the fabric and making the whole thing airtight) would increase lift of the balloon by 4 times for the same volume and might make balloon craft viable. Especially if you use them to bomb from say... 8 000ft. Not going to meet many flyers there, but will have to deal with bad weather.

Rocket
The steam rocket is iffy. It's useful if you can get it to lift at least half the best case weight (or even more). Say, using a central boiler and feed tubes to rockets that can change angles.
Very high thrust, good maximum speed for strafing, ability to hover and VTOL.

The problem is in the design. A De Laval nozzle requires understanding of gas laws that they don't know, and without it, the thrust is significantly reduced.
Furthermore, boilers are dangerous. A few hundred kW boiler drives trains and can level a small building on explosion. A gigawatt boiler?! That'll blow your ship apart like so much wet toilet paper.

Gust of Wind
Bad: Absymally low thrust for cost, relatively slow speed
Good: Completely internal, high maneuverability

This one I think it's better to not rely on for main thrust. To use as engines to drive balloons or mechanisms that generate only lift is less costly.

eg. 1 gust of wind box lifts 283 kg. 10 tons requires 35.3 engines, each costing just over 8000gp and requires many castings of 11th CL permanency.
A single Wall of Fire 12th CL permanency is easier to obtain.

Flying Carpet
Bad: 10th CL item, 20 castings of 10th CL overland flight to craft (at most 1 per year), slow, weak weight limit
Good: No risk of mechanical failure, easy to use and deploy, can hide among normal high-quality rugs for trade in order to smuggle it for whatever reason

I can see this being used in very high priority covert missions. Short of that, no way will this see general military use.

****************************************

Portable Holes and Ring Gates are out. While there are designs that could move moons with those, they're simply too high CL to create.

When you have to bargain with extraplanar entities for the rare few high level scrolls, high CL items are just right out.

Also, trap rules are out. Just because.

I've edited the 1st post to include the constraints as well.

Randel
2009-12-21, 07:51 PM
A few thoughts:

1. If you are having a giant balloon keep the craft afloat then make sure its compartmentalised or made into sections... not really sure if its doable using a hot air balloon (with a helium balloon you just need alot of airtight balloons to do the lifting, with hot air you need a way to keep all the hot air going into the various pockets and let the cooled-off air get out). That way if one or more of the sections are damaged then the other parts will still keep it up long enough to let it still fly or land safely.

2. Repairing magic would be useful to fix tears in the balloon, or have little imps crawl on the balloon and use big sheets of duct tape or something.

3. Propellers should be doable, with a decanter of water and a permanant wall of fire then you can make a steam engine that works forever (or until it breaks down... though magical repair could keep it working) Not sure if you could make a flying ship that is kept aloft by millions of helecoptor rotors powered by magical perpetual motion steam engines... but you could use the propellers to move the ship and steer and stuff.


4. Build some kind of crazy super-jet engine by using walls of force and then a localized Control Wind spell inside it to create hurricane level winds rushing through. Be sure to strap it on securely to whatever you want airborn (especially since the walls of force are invisible in addition to being indestructable and I can't thing of a way to turn s Control Weather jet engine off... so once you enchant it then it had better be strapped securely to something heavy or you'll have an invisible perpetual motion jet engine flying around generating wind speeds strong enough to rip trees out of the ground... or more approptiatly cut down forrests by ramming into them with indestructible force-walls).

Johel
2009-12-21, 08:11 PM
Wouldn't sorcerers be the best bombs. You just fly the ship 600 feet high and have them cast fireballs through small opening. If you only have characters up to level 9 and the SRD I think it would be a good choice. If it's a strategic bomber you can kill most commoners and low level soldiers with them and they can set flammable medieval cities on fire. Blasting may be suboptimal in normal combat but with bombers you'll want to kill/destroy a lot of people/things from a distance without having to finish the job by actually going down for the coup de grace.

1st level sorcerers on a pegasus, blasting the city with wands.
Who needs an airship when mere mounts can do the trick ? :smallamused:

Now, why make it simple if you can make it complicate ?
Create a "Minor Creation" trap, built on the airship's belly.
It will produce 7 cubic feet of petroleum every minute.
Said petroleum will exist for 7 hours.
That means you can store up to 11.760 liters
Let's make it 11.000 liters, that's still a nice shower on the target.
Now, just lit torches, drop them... and watch the city burn.

Alternatively, you could just magically create a looooooooooong necklace with 1.5 lb balls of wood. As unpractical as it is, it's still a "nonmagical, unattended object of nonliving, vegetable matter". Now, cut the string and drop the balls from an altitude of 1.400 feet. 20d6 damage per ball on impact.

If you got a trap of "Major Creation", you can actually make the same with balls of pure gold. They'll be a lot smaller, meaning you'll have more of them per casting, which means more damage. The best part ? All of it will simply vanish about 3 hours latter.

jseah
2009-12-21, 08:11 PM
Control Winds is a good one. The rare 9th level druid could cast that and power a huge sail via the updraft method. (or be on the inside of a balloon and do it)

One and a half hours is a bit little, but a few castings will take care of that.

Are there ways to get 3 CL in boosters? Need CL 12 to get a control winds spell to generate hurricane force winds.

Jack_Simth
2009-12-21, 08:21 PM
Okay... so...

We get some horses, equip the equines with Horseshoes of a Zephyr (http://www.d20srd.org/srd/magicItems/wondrousItems.htm#bootsofLevitation) (caster level 3, 6k for a set of four suitable for one horse), and hang a treadmill off of the horses. The only purpose of the treadmill is to make a surface underneath the horses (and to do vertical control - tilt it up or down slightly to ascend or descend, respectively). D&D has well-defined rules for how much a horse can carry. It's a simple matter to make horses do what you want. Now all you have to figure out is what the weight of the treadmill will be (and how to land it safely).

Slayn82
2009-12-21, 09:16 PM
And i was smiling thinking we would make Castle Wulfenbach (http://images3.wikia.nocookie.net/girlgenius/images/3/36/CastleWulfenbach.png). Oh, well.

If a FIREWALL is enclosed in a Alembic/Pot - like structure, it can at least count with a blocked line of sight, that will protect it from dispell magic and disjunction. Just saying.

Would be all troublesome to run some backup balloons to lift the Castle in case of damage? Specially if they could be inflated very quickly, as the resources allow.

Maybe your mages could research a FIREWALL spell with duration: Concentration, to run the smaller baloons. Or just use hydrogen balloons, from the reaction between Strong Acid + Metal.

Also, leaving trails of burned sulfur would make a bad day for many attackers. Fog spells could prevent the detection of the ship (look, a strange cloud), and if you can field Sorcerers/ Adventurers on Pegasus, they would make good interceptors protecting the Castle. And often, in case of a surprise attack, the fall of the Castle would be as much disastrous for the defender as for the attacker.

For the Castle Speed, well, depending of the weight of it, it can still be pretty fast. There will be a lot of extra hot air to be diverted right out of it, if you can just add more Gust of Wind sources, or maybe a secondary engine system.

jseah
2009-12-21, 09:19 PM
You could do it. As I calculate above, the power output of wall of fire at 10% efficiency of our current flamers could fill a balloon 5 times the size of the Hidenburg zeppelin.

And lift 340 tons.

I point out that 340 tons isn't exactly alot of weight when you need to protect a balloon more than 1km long.

Radar
2009-12-22, 03:53 AM
If it's an all out war, then just drop some Wights at enemy cities in the night. Even if they ar 4th to 7th level PCs, such a tactic would wrack havock and be quite effective. Especially, if you use it after softening your enemy up with something else, or do a sneaky high-altitude wight-bombing deep in enemy's teritorry.

Rocket
The steam rocket is iffy. It's useful if you can get it to lift at least half the best case weight (or even more). Say, using a central boiler and feed tubes to rockets that can change angles.
Very high thrust, good maximum speed for strafing, ability to hover and VTOL.

The problem is in the design. A De Laval nozzle requires understanding of gas laws that they don't know, and without it, the thrust is significantly reduced.
Furthermore, boilers are dangerous. A few hundred kW boiler drives trains and can level a small building on explosion. A gigawatt boiler?! That'll blow your ship apart like so much wet toilet paper.

You got yourself a bomb right there: Wall of Stone -> Shape Stone to create a sphere (or a cylinder) with an opening and two chambers yet to be separeted -> Wall of Fire in one chamber -> Shape Stone to close it -> fill the other with water (from your Decanters) -> Shape Stone to close the whole thing -> drop it before it blows in your hands. Adjust walls thickness to get desired peak pressure at wich it will blow.

jseah
2009-12-22, 05:06 AM
I've considered wights. There are a few problems, solve these and it should work.
1. Wights can't survive 20d6 falling damage (they have an average of 8d6 hp)
2. Wights are CR3. If the CR system is to be believed, they're around 1 normal person in power. Sure, they'll kill a few, but can't quite get off the ground if every peasant and his uncle has 3 class levels or more.

Other than that, wights do cause rather alot of damage and won't turn into a wight-o-clypse since heavy NPC resistance is expected.

*********************************************

Pressurized water bombs would be better if you could get them to work. Since you only need to carry the bomb casing, you can get more bombs for your weight.

Filling and "charging" the bombs with heat will take time though. So only applicable to heavy-lift type craft, like balloons or floatation devices.

EDIT:, they don't cause the same amount of damage as oil ones do though.

Prime32
2009-12-22, 05:19 AM
Oh, you want to use these for combat? Here's a weapon idea for your flagship:

Eberron's Lightning rail is essentially a magical mag-lev train - the tracks and the underside of the carriage are fitted with "conductor stones" - when two are in close proximity they generate a repelling field.

Make a giant barrel out of some durable substance and line it with conductor stones (in as dense a pattern as possible - have ogres sovereign glue them to walls of force if necessary), then cast a permanent control winds spell on it to create a hurricane-force wind flowing through it in one direction. Set up a magic trap on one end which imbues any object placed within with the properties of a conductor stone for 1 round. You now have a very powerful coilgun (http://en.wikipedia.org/wiki/Coilgun). You might want to build a "cap" on it to prevent sabotage (and block the light emitted by the stones), or tip the barrel with pandemoniac silver to scare people who get too close (it creates a fear effect with a save DC depending on wind speed).

Deth Muncher
2009-12-22, 05:22 AM
Y'know what's confusing about this thread? Different countries write thousands differently.

Me, being in America, think one thousand as "1,000".

In this thread, I've seen both "1 000" and "1.000".

I just don't know what to think any more. >_<

jseah
2009-12-22, 05:29 AM
Oh, you want to use these for combat? Here's a weapon idea for your flagship:
<...>
Nice. I'll go look up the cost. Although I'm not sure if that kind of railgun can give enough power.

Besides, enemy flying craft aren't expected. Just flyers.

****************************
Deth:
1 000 and 1,000 are both one thousand clearly enough

1.000 means 1, accurate to 4 significant places. Not one thousand unless it's a typo.

Prime32
2009-12-22, 05:35 AM
Nice. I'll go look up the cost. Although I'm not sure if that kind of railgun can give enough power.

Besides, enemy flying craft aren't expected. Just flyers.Coilgun (railguns have a single moving charge that draw the projectile along). And you'd be surprised. The combined force of hundreds of powerful magnets and hurricane-force winds? Build 'em large enough and they rival nukes (http://halo.wikia.com/wiki/Magnetic_Accelerator_Cannon), and that's not even taking the properties of the projectile into account (my biggest worry would be that the missile would disintegrate from the speed unless the trap also casts magic weapon on it).

jseah
2009-12-22, 05:39 AM
I understand the principles of a coilgun or railgun. It's that Eberron conductor stones conduct magic, not electricity.

Furthermore, the Lightning Rail is apparently air-elemental powered. >.<

It doesn't have anything to do with lightning at all.

Prime32
2009-12-22, 05:41 AM
I understand the principles of a coilgun or railgun. It's that Eberron conductor stones conduct magic, not electricity.

Furthermore, the Lightning Rail is apparently air-elemental powered. >.<

It doesn't have anything to do with lightning at all.That doesn't matter - the point is that the conductor stones repel each other, so that force can be used to propel a missile (especially if you force the stones closer together than would normally be possible).

An elemental isn't needed - they just supply the forward momentum for the carriage, and have nothing to do with the conductor stones which raise it from the ground. You can buy conductor stones as a separate item, though it might be cheaper to buy full carriages and strip them (use the carriage itself as part of the airship).

jseah
2009-12-22, 05:55 AM
Well, the setting isn't Eberron (although I use material from there) so simply making the stones works.
Also, how much is one stone and what CL?

Repulsion of the stones does nothing except to prevent the levitating one from touching your walls or floor. Are you going to shoot a Conductor Stone for every shot? And how is the acceleration going to happen?
Hurricane force winds aren't nearly powerful enough. There aren't enemy vessels to shoot at. And ground targets tend to require much more energy to destroy.

Prime32
2009-12-22, 06:18 AM
Well, the setting isn't Eberron (although I use material from there) so simply making the stones works.
Also, how much is one stone and what CL?I can't recall, though it's probably expensive enough that you can only build one of these things, and an artificer with cost-reducers is advised.


Repulsion of the stones does nothing except to prevent the levitating one from touching your walls or floor. Are you going to shoot a Conductor Stone for every shot? And how is the acceleration going to happen?
Acceleration happens from the stones pressing strongly on the projectile and attempting to force it out of the barrel. And they are quite powerful - it's very difficult to bring two stones close together. And each projectile only needs to last one round, so you should be able to imbue them with the required properties for 1 round easily enough, right? :smallconfused: (you could even create 1-round projectiles which leave no trace after being fired)


Hurricane force winds aren't nearly powerful enough. There aren't enemy vessels to shoot at. And ground targets tend to require much more energy to destroy.The winds are mainly there to ensure that you can load the projectiles properly (ie. it won't be immediately forced back out), and that people on the outside can't throw conductor stones into your barrel and make you shoot the inside of your ship.

Plus, what if the rounds are filled with bombs which detonate after you penetrate the ceiling of your target (or summoning spells for that matter)? Or you could fire fragmentation rounds at armies.

Triaxx
2009-12-22, 06:23 AM
Doesn't matter how much energy the ground target takes. You can essentially be shooting gravel at it, and still be doing 40d6 damage. (Estimate, I haven't run the numbers.) In any case, you're still over coming hardness. And the magical trap is there to enchant anything you want to shoot as a conductor stone for 1 round. So you're not actually shooting anything too valuable. Unless you push the Gnome Rogue in. Which would be hilarious.

Prime32
2009-12-22, 06:26 AM
Unless you push the Gnome Rogue in. Which would be hilarious.

http://chattydm.net/wp-content/uploads/2008/06/gnomemonster.jpg
I'm a missile! Raar!

jseah
2009-12-22, 08:07 AM
I see. You're using the conductor stones as springs to store energy.

That's not a coilgun. But still, worth looking at.

***********************************************

Assuming repulsion on conductor stones is inverse square law, pressing them close would take enormous amounts of force. Far more than what you can exert even with a wall of fire boiler.

Say you charge your gun by using hardened adamantine jacks powered by the wall of fire steam engine.
Then put a shell in front of the ball, and sever the connection to the jacks, allowing the ball to proceed down the barrel with a path length of a few tens of meters.
You catch the ball from flying out via a heavily hardened obdurium ring or some such thing, who's central hole allows the projectile out.

Could work. Then energy depends on your jacks and how you charge it. Still, with a 12GW boiler and a charging routine of a minute or so, you're going to at least get 1 GW into your projectile.

Slayn82
2009-12-22, 08:47 AM
Doesn't matter how much energy the ground target takes. You can essentially be shooting gravel at it, and still be doing 40d6 damage. (Estimate, I haven't run the numbers.) In any case, you're still over coming hardness. And the magical trap is there to enchant anything you want to shoot as a conductor stone for 1 round. So you're not actually shooting anything too valuable. Unless you push the Gnome Rogue in. Which would be hilarious.

Well, this allows for an adaptation of this idea:


The resilient sphere is probably the best trick, but as an alternative that punches great craters, how about giving the kingdom some way to cast over their soldiers Meld into Stone, and drop a large boulder down all the way to the target with catapults?

It puts some nice limitations, like just 100 pounds of non living gear, and some advantages, like allowing the subject to cast spells. Also, if the transporting rocks could be the source of the effect, being magically fortified to resist impact and desintegration, and allowing the guard members to meld with it, plus a teleportation effect like word of recall once per day that could be used over it to send it back to the base. And of course, the size of the rock could be a limiting factor to determine how much it could carry. And its size, weight, resistence and other possible shenigans could explain a lot of other uses, at GM discretion.

Well, now we can throw the Wrights at them, even if we make the projectiles disposable.

Prime32
2009-12-22, 09:27 AM
I see. You're using the conductor stones as springs to store energy.

That's not a coilgun. But still, worth looking at.

***********************************************

Assuming repulsion on conductor stones is inverse square law, pressing them close would take enormous amounts of force. Far more than what you can exert even with a wall of fire boiler.

Say you charge your gun by using hardened adamantine jacks powered by the wall of fire steam engine.
Then put a shell in front of the ball, and sever the connection to the jacks, allowing the ball to proceed down the barrel with a path length of a few tens of meters.
You catch the ball from flying out via a heavily hardened obdurium ring or some such thing, who's central hole allows the projectile out.

Could work. Then energy depends on your jacks and how you charge it. Still, with a 12GW boiler and a charging routine of a minute or so, you're going to at least get 1 GW into your projectile.
Not exactly. What I was saying is make a tube out of walls of force, then sovereign-glue conductor stones to the inner surface (enveloping the others in antimagic fields while you're working). After that, if you fire something with the properties of a conductor stone through the tube it should be accelerated by the repulsive force (which is where the hurricane-force winds come in - if its too slow the projectile won't be able to enter the tube).

Lysander
2009-12-22, 09:33 AM
Here's another idea: animated wings. From the animated objects creature description:


A sheetlike object can fly (clumsy maneuverability) at half its normal speed.

Animate a large number of squares of sailcloth then stitch them together. You could make sails or wings that would flap on command. I could see an airship being held up by a few giant sets of constantly beating wings.

jseah
2009-12-22, 09:34 AM
Ah. I see, what a cunning plan you have.

A line of conductor stones in AMF, which then turns off right when the firing stone passes by, ready to repel it.

Still going to cost a lot to fire, but it'll sure carry alot of energy.

Here's my modification. The loading just needs one more conductor stone at the end. It's in an AMF.
During Ready To Fire phase, the firing stone is loaded into the tube and all the conductor stones on the side are in AMF.
During Firing, the stone right behind the loading position turns on and pushed the firing stone forward, past the first ring, which then turns on and adds extra power and so on.

Each ring exerts the same amount of force but over a shorter time. (as the firing stone is traveling faster)

If you mount this on the giant blimp, you could do around 100 rings. Possibly bringing firing stone to a significant fraction of light speed.

***********************************************

I can't find the cost and CL for conductor stones in eberron. Weird that.

Also, repulsion force of the stones is unknown.

jseah
2009-12-22, 09:47 AM
Animate a large number of squares of sailcloth then stitch them together. You could make sails or wings that would flap on command. I could see an airship being held up by a few giant sets of constantly beating wings.
Excellent idea.

Notes:
This costs 1 high level scroll (preferably CL20) of Animate Objects and one CL14, 3000xp scroll of Permanency
- Cost per casting: 19 750gp

Things that can fly need to carry light load. Doing the calculations for the number of objects affected per casting of Animate Objects (and the more expensive Permanency), Small sheets are the best for this.

20 small sheets, each with 8str, can lift 26lb ea, leads to 520lb = 235kg of lift.

Sorry, this is less efficient than Gust of Wind drives.

Ormur
2009-12-22, 09:51 AM
Deth:
1 000 and 1,000 are both one thousand clearly enough

1.000 means 1, accurate to 4 significant places. Not one thousand unless it's a typo.

No he's quite right it differs from country to country. Where I'm from we write one thousand as 1.000 and one accurate to four significant places as 1,000.

jseah
2009-12-22, 09:58 AM
No he's quite right it differs from country to country. Where I'm from we write one thousand as 1.000 and one accurate to four significant places as 1,000.
o.O That's news to me. Which country?

I got to get my hands on a physics paper from there just for kicks when my friends misinterpret it all over. XD

(Why is g = 9813 m s-2 ? why?!?!)

Ormur
2009-12-22, 10:22 AM
I'm from Iceland and we follow Scandinavian customs but it seems the whole of continental (http://en.wikipedia.org/wiki/Decimal_separator#Examples_of_use) Europe (http://en.wikipedia.org/wiki/File:DecimalSeparator.png) does it that way, although they recommend using spaces instead of either a point or a comma as a thousand separator in science papers. You say one point three, we say one comma three. Once again the English speaking world does is differently. :smallsmile:

Johel
2009-12-22, 10:27 AM
o.O That's news to me. Which country?

...I guess most of European countries ? :smallconfused:
At least, that's the way I've learned it.

Excel and most accounting softwares use the "1.000,00 " = "a thousand euro and zero cents", so I'm sure the use of "1.000" instead of "1,000" is the standard in Belgium, France, Netherlands and Germany for financial datas. Likely, the rest of Europe uses it, too, with maybe the exception of UK.

Now, I don't know for scientific datas.

Lysander
2009-12-22, 10:37 AM
Excellent idea.

Notes:
This costs 1 high level scroll (preferably CL20) of Animate Objects and one CL14, 3000xp scroll of Permanency
- Cost per casting: 19 750gp

Things that can fly need to carry light load. Doing the calculations for the number of objects affected per casting of Animate Objects (and the more expensive Permanency), Small sheets are the best for this.

20 small sheets, each with 8str, can lift 26lb ea, leads to 520lb = 235kg of lift.

Sorry, this is less efficient than Gust of Wind drives.

Perhaps the sails aren't best used as a drive but as a way of steering. You could also animate the box the Gust of Wind in to direct where it points.

jseah
2009-12-22, 10:55 AM
XD Thanks. You learn something new every day. Or so it's said.

About Conductor Stones:
They have a repulsion force so high that even a coach weighing 100 tons can't force it closer than a few feet (but less than 5)

That's... a pretty high force.
assuming it's 100 short tons = 200 000 lbs = 90 718 kg. That's a supporting force of 889 948 N. (!!)

Assuming you start from 3 feet, and the force decreases linearly to 0 at 5 feet...
Each conductor stone puts out 542 512 J of energy.

If each ring has 4 stones, and there are 100 rings plus 1 initiating stone... Projectile has final energy of 217 547 489 J.
217 MJ. Assuming the conductor stone you're firing weighs 1kg, it has a speed of 20 859 m s-1. (newtonian 0.5 m v^2 calculation)

Around 60 times the speed of sound. That's going to do some major damage.

Too bad you got to fire a conductor stone each shot. =/

************************************************** ***

EDIT: Calculation error. Energy output is half that.

Speed is actually 14 749 m s-1. Around 43 times the speed of sound.

Storm Bringer
2009-12-22, 01:13 PM
if you added the conductor enchantment after inserting the stone, you could bypass all the loading diffculties (as the stones only repel each other, right?) just plop the inert stone in, cast one round chantment on it, and boom! off it goes.

something like this is gonna be a spinal mount job, and i'm not sure how much effective recoil it would produce.

Can force be transmitted though a wall of force? will the 200 MJ of energy put into the round be transfered though the wall of force barrel and into the hull of the ship?

if so, your gonna need to build the hull out of walls or force or this is gonna rip off it's mountings every time it's fired.

wiki claims, in it's "this much energy is equal to roughly this real world event" section of Joules, that 1 MegaJoule is aproximatly 1 ton moving at about 100mph.

So, this gun has enough kick to move a 200 ton object at about 100mph.

other problems:

at that sort of velocity, whatever you shoot is likey to come apart on impact. thier comes a point, when striking a unyeilding surface (like a stone wall) when the the shock of impact will fragment a round before it can penatrate the target. while this may be desriable for a frag round, agianst a hard target (say, the walls of a castle) you are going to want to have a force effect on the round to allow penatration into the target and proper transfer of energy into the target

jseah
2009-12-22, 01:22 PM
if you added the conductor enchantment after inserting the stone, you could bypass all the loading diffculties (as the stones only repel each other, right?) just plop the inert stone in, cast one round chantment on it, and boom! off it goes.
The proposed method uses AMF to toggle the conductor stones. So yeah, it's the same thing. Just that one-round enchantments for conductor stone mimicry don't exist.


something like this is gonna be a spinal mount job, and i'm not sure how much effective recoil it would produce. can force be transmitted though a wall of force? if so, your gonna need to build the hull out of walls or force or the is gonna rip off it's mountings every time it's fired.
Agreed about the spinal mount thing. Only good vs stationary targets or other airships.

The recoil is spread evenly through all the conductor stones. It won't blow it's mounting if you do it properly.
eg. like how they secured the Lightning Rail stones to the ground


at that sort of velocity, whatever you shoot is likey to come apart on impact. thier comes a point, when striking a unyeilding surface (like a stone wall) when the the shock of impact will fragment a round before it can penatrate the target. while this may be desriable for a frag round, agianst a hard target (say, the walls of a castle) you are going to want to have a force effect on the round to allow penatration into the target and proper transfer of energy into the target
That may be right, I'm no expert at ballistics. All I know is, more energy = more firepower.

Do you think a round 1 kilogram metal ball will fragment against a stone wall? It'll damage the wall surely? Or do we need shaped adamantine shells?

jseah
2009-12-22, 01:38 PM
Right, I'm forgetting my stuff.

I remember designing an optical weapon using Daylight, a Hallow spell and high-reflective mirrors.

Time to run calculations again.

Storm Bringer
2009-12-22, 01:49 PM
The proposed method uses AMF to toggle the conductor stones. So yeah, it's the same thing. Just that one-round enchantments for conductor stone mimicry don't exist.


Agreed about the spinal mount thing. Only good vs stationary targets or other airships.

The recoil is spread evenly through all the conductor stones. It won't blow it's mounting if you do it properly.
eg. like how they secured the Lightning Rail stones to the ground


That may be right, I'm no expert at ballistics. All I know is, more energy = more firepower.

Do you think a round 1 kilogram metal ball will fragment against a stone wall? It'll damage the wall surely? Or do we need shaped adamantine shells?

with the sort of energy we are talking about, no real-world material would survive the impact. Steel shot shatters (as in, like a glass sheet) at about 2,800 ft/s.

A shaped adamantine long rod penatrator (i.e. as used in modern at rounds (http://http://en.wikipedia.org/wiki/File:Obus_501556_fh000022.jpg)) would fare better. we can get a modern sabot round up to about 6,000 ft/s, and likey faster if we could find a better proellant. current long term RnD projects are making tank guns with a muzzle energy of about 18MJ. To take the full 200 MJ power your likey looking at a force effect for the forward edge.

the downside of a force effect is the chance of overpenatration: the round punching a neat hole though both sides of a target ship and sailing off into the distance with most of it's energy. with an unbreakable edge, this could well happen agianst a ship style target, and it would effectivly leave the target unhurt (two small holes in the hull. 30 seconds to patch, and your good). damage to a target is about the transfer of energy, so a slower round that transfers all it's power is better than a faster round that onls transfers some.


I think adamantine long rod rounds, with a lower total energy, might be the best bet.

At the moment the total energy of this beast is almost entirly wasted.

jseah
2009-12-22, 02:09 PM
So you have two types of shell.

One is a HE shell, for use vs airships as they have wooden (or soarwood) hulls. Shrapnel can rip a huge hole at the energies we're talking about.
The main problem in this shell is designing it to fragment not merely punch a hole through the target ship. (if you hit something metal, then you're lucky, but dense metallic things are rare on an airship)
The HE shell would have a large flat surface to increase area of impact and use something weak and cheap, like wrought iron, to increase chance of shattering and killing crew.
It'll also be heavy to reduce penetration but increase shrapnel. Doubling weight lowers speed by sqrt2. Taking your 2800ft/s = 853.44 m/s number for iron shattering for a target muzzle velocity at twice that, and the muzzle velocity estimate of 14 749 m/s for 1kg gives a shell weight of 149kg.

The anti-armour shell, for use vs castles and fortifications, would be light and shaped. Hardened Adamantine should do (DR 40 vs iron's DR 10).
Would need ballistics tests to get it right, but I'm guess the shell would be made to penetrate a few feet into stone, thus delivering most of it's energy in the middle of the wall for maximum effect.
EDIT: As it is, I can see even adamantine shattering if you just cover the Conductor Stone with it. Reduced weight needed.

Good, I'll use this gauss gun thing for the "end-game".

Any estimates on effective range? I think it could probably shoot 2 or 3 km since you're attacking from a height. Angling the ship would be a problem of course, since the 505ft long tube can't exactly be turned.

Radar
2009-12-22, 02:19 PM
I've considered wights. There are a few problems, solve these and it should work.
1. Wights can't survive 20d6 falling damage (they have an average of 8d6 hp)
2. Wights are CR3. If the CR system is to be believed, they're around 1 normal person in power. Sure, they'll kill a few, but can't quite get off the ground if every peasant and his uncle has 3 class levels or more.

Other than that, wights do cause rather alot of damage and won't turn into a wight-o-clypse since heavy NPC resistance is expected.
1. Well, duh! Parachutes. :smalltongue:
2. Yes, that does pose a problem. The solution would be to change the tactics: use wight-troopers to raid secluded farms, cottages and small villages preferably deep in the enemy's territory. Such places are less likely to have a lot of guards on duty and wights are quite sneaky undead, so they would have a significant chance of offing a lot of peasants in their sleep. Besides, they heal on a successful drain, so they have a fair chance against a 4th level character if 1 on 1. For others, there is numbers superiority. Generally it won't trigger wight-o-calypse, but it might be a reliable way to mess up supply lines and food production.

Solution to both 1 and 2: use Greater Shadows instead. They are incorporeal, so won't be hurt by falling (they fly), can't be damaged by nonmagical weapons and can pass through walls and such. Why didn't I thought of them in the first place? :smallconfused:


Pressurized water bombs would be better if you could get them to work. Since you only need to carry the bomb casing, you can get more bombs for your weight.

Filling and "charging" the bombs with heat will take time though. So only applicable to heavy-lift type craft, like balloons or floatation devices.

EDIT:, they don't cause the same amount of damage as oil ones do though.
Going by your calculations from earlier in this thread, 25 sq ft of Wall of Fire gives about 12 MW of heat. Let's put it in a 5x5x5 ft box made of whatever (some stone preferably, since one can produce it on spot with a spell). Put the box in a thin stone sphere sized exactly to fit into a Resilient Sphere. Fill the sphere with water. Cast Resiliant Sphere on your stone sphere. Build a wooden box around the Resiliant Sphere. It's enclosed, so it counts as a location. Thus you can drop the Resiliant Sphere as a bomb. When the box htis the ground, it will fall apart, so the sphere will be pinned to it's new location per spell's description. The bomb will explode, when the spell would end. If you are consequent with using stone material, you don't need to transport anything except the parts for wooden boxes (might be replaced with a stone box as well). You only need some time and a few casters, to shape things up, when close to destination.

As for the payload:
the Resiliant Sphere probably conducts radiation (since it doesn't block sight), so the maximum internal temperature is limited by heat radiation. Assuming for simplicity that the sphere locked in the spell is an ideal black body and that the temperature is even in the whole volume (not realistic, but I can't be bothered with solving heat transport equation right now) for a sphere of 7 ft in diameter (7 CL is minimum for Resiliant Sphere), which is just enough to contain the Wall of Fire box and some water we get 27 m^2 of surface and a temperature of about 1672 K. If the sphere contained only air, it would get a preassure of only 5,7 atm. Now, if one fill all the leftover place
(37 m^3) with water, it gets up to 9120 atm or 8294 atm if the box containing Wall of Fire collapses under preassure. Calculating ammount of stored energy is an exercise for the reader. :smalltongue:
Remember, that if one enlarges the device proportionally (which means, along with the heat source), it's internal temperature and preassure will be greater. Is it good enough? :smallbiggrin:

EDIT: as far as demolishing round go, they don't have to penetrate the wall. They are designed to tear the wall down, so a lead round, that goes *splat* on a wall is perfect - it transfers it's whole energy to the wall that needs to be crushed. Instead of a small, deep hole (through mulitple walls probably), one gets a large part of the wall in ruins. Even anti-tank rounds are not meant to penetrate the armour - they go *splat* on the surface and the preassure wave creates lots of shrapnels on the inside to hurt anyone in the tank.

jseah
2009-12-22, 02:36 PM
1. Well, duh! Parachutes. :smalltongue:
2. Yes, that does pose a problem. The solution would be to change the tactics: use wight-troopers to raid secluded farms, cottages and small villages preferably deep in the enemy's territory. Such places are less likely to have a lot of guards on duty and wights are quite sneaky undead, so they would have a significant chance of offing a lot of peasants in their sleep. Besides, they heal on a successful drain, so they have a fair chance against a 4th level character if 1 on 1. For others, there is numbers superiority. Generally it won't trigger wight-o-calypse, but it might be a reliable way to mess up supply lines and food production.

Solution to both 1 and 2: use Greater Shadows instead. They are incorporeal, so won't be hurt by falling (they fly), can't be damaged by nonmagical weapons and can pass through walls and such. Why didn't I thought of them in the first place? :smallconfused:
Well, NOT causing a wight-o-clypse is actually a good thing. Since you don't want everyone on the planet dead.

That said, it's a very good terror tactic and excellent for undercover operations. Thank you, I'll use it.

Might need to train them to use a 'chute. Or plant them in enemy territory covertly and simply order them, "Attack targets of opportunity. Don't get killed. Repeat orders to subordinates. See ya!"

Wight Paratroopers! Stand...by! 3! 2! 1! Go!


Now, if one fill all the leftover place
(37 m^3) with water, it gets up to 9120 atm or 8294 atm if the box containing Wall of Fire collapses under preassure. Calculating ammount of stored energy is an exercise for the reader. :smalltongue:
Remember, that if one enlarges the device proportionally (which means, along with the heat source), it's internal temperature and preassure will be greater. Is it good enough? :smallbiggrin:
Why... yes, it is good enough. Use for bombs meant to destroy targets not susceptible to burning. Like churches or fire-shelters.

Resilient Sphere, CL7, 1 min/level
Wall of Fire, CL7, Concentration + 1 rnd/level
Wall of Stone, CL9... needs scrolls if you're going to have a significant amount of bombs. EDIT: CL9 casters are rare
- Just use iron bombshells. With a cover that you can seal.
- Then wooden boxes for the resilient sphere

Expected problems:
Resilient Sphere lasts too long. 7 mins drop time is long.
Bombs released at 12 000ft take at most just over a minute to hit. Ideally, you want it to blow up as soon as it hits the ground to prevent enemy casters from defusing it.

jseah
2009-12-22, 02:44 PM
EDIT: as far as demolishing round go, they don't have to penetrate the wall. They are designed to tear the wall down, so a lead round, that goes *splat* on a wall is perfect - it transfers it's whole energy to the wall that needs to be crushed. Instead of a small, deep hole (through mulitple walls probably), one gets a large part of the wall in ruins. Even anti-tank rounds are not meant to penetrate the armour - they go *splat* on the surface and the preassure wave creates lots of shrapnels on the inside to hurt anyone in the tank.
The thing is that shrapnel will probably just stick in the stone or bounce off. Most of the energy in a shattering round might go into the shrapnel.

Yes, they'll shred anyone nearby, but you'll rather destroy the tower. In that sense, a shell that goes halfway through a wall and then shatters is best.

Knaight
2009-12-22, 02:46 PM
Nice. I'll go look up the cost. Although I'm not sure if that kind of railgun can give enough power.

Besides, enemy flying craft aren't expected. Just flyers.

****************************
Deth:
1 000 and 1,000 are both one thousand clearly enough

1.000 means 1, accurate to 4 significant places. Not one thousand unless it's a typo.

Depends on the country. Some have 1,000 as 1, accurate to 4 significant digits, others 1.000, basically commas and periods swap in some places.

jseah
2009-12-22, 03:09 PM
Knaight: Thanks, I know that now.

*****************************************

Daylight: 3rd level spell, most military wizards can cast it.

60ft sphere has a surface area of 45 239 sq ft = 4 203 sq m
Sunlight average wattage: 1.366 kW/m

Power Output of a Daylight spell = 5.741 MW

Assuming a tweakable reflector, you can take about half that power and refocus it onto the target point. 2.8 MW irradiance, aimable turret, range at least 1km line of sight.

Could this work?

Radar
2009-12-22, 03:22 PM
Expected problems:
Resilient Sphere lasts too long. 7 mins drop time is long.
Bombs released at 12 000ft take at most just over a minute to hit. Ideally, you want it to blow up as soon as it hits the ground to prevent enemy casters from defusing it.
Well, one option is to wait out some time, but it's not very wise, since the external box won't last long enough in such a hot enviroment - might be good to replace it with an iron casing. It could be hanged for those few minutes on a line under the blimp, so it won't damage the ship.
Other then that, once the bomb heats up, it can't be diffused that easily. You can't cool it without taking the Resiliant Sphere out and if one does remove the Resiliant Sphere, it's too late for anything. One might try to contain the blast by building some sort of upward deflector or they can try to evacuate the area, which is not much of a concerne - with a flattened city, living citizens can create more problems to the nation, then casualties. They need to get shelter, food and other comodities and it drains resources significantly. Between this and the wight/shadow commandos roaming the countryside and roads, things will get ugly for your enemies.


The thing is that shrapnel will probably just stick in the stone or bounce off. Most of the energy in a shattering round might go into the shrapnel.

Yes, they'll shred anyone nearby, but you'll rather destroy the tower. In that sense, a shell that goes halfway through a wall and then shatters is best.
At these energies, things won't shatter or bounce off - they will melt. You do want the round to stick to the wall - that's the most efficient way of transfering the whole energy to the target.

Prime32
2009-12-22, 03:46 PM
Ah. I see, what a cunning plan you have.

A line of conductor stones in AMF, which then turns off right when the firing stone passes by, ready to repel it.
Nah, you can leave them on all the time, since unlike a normal coilgun you don't have to worry about magnetic poles. I meant you'd need the aid of an antimagic field while assembling this thing, so that you could glue so many conductor stones so close together.

You could also set up some kind of loop in the barrel to build up speed.

There was an episode of Mythbusters where they loaded a cannon with iron chains - it did nasty spread-out damage.


...I guess most of European countries ? :smallconfused:
At least, that's the way I've learned it.

Excel and most accounting softwares use the "1.000,00 " = "a thousand euro and zero cents", so I'm sure the use of "1.000" instead of "1,000" is the standard in Belgium, France, Netherlands and Germany for financial datas. Likely, the rest of Europe uses it, too, with maybe the exception of UK.

Now, I don't know for scientific datas.
In Ireland it would be "1,000.00" - are we not part of Europe? :smallamused:

jseah
2009-12-22, 03:55 PM
Nah, you can leave them on all the time, since unlike a normal coilgun you don't have to worry about magnetic poles. I meant you'd need the aid of an antimagic field while assembling this thing, so that you could glue so many conductor stones so close together.
No you can't leave it on all the time.

If the coils are fixed in place, then passing a bullet through an active coil doesn't net any energy. It takes just as much energy to get to the middle of the coil as it gains in exiting.

What you need to do is turn the coil off until the bullet reaches the middle, then turn it on.

EDIT: loops are also complicated. A bit difficult to stabilize that. Spin too fast, and the bullet will escape. Spin too slow, it smashes into the inside of your loop.

Prime32
2009-12-22, 04:00 PM
EDIT: loops are also complicated. A bit difficult to stabilize that. Spin too fast, and the bullet will escape. Spin too slow, it smashes into the inside of your loop.You could do one with portals of some kind, but at that point you could just use the "unlimited-use ring gates in a vacuum" trick to accelerate your bullet to infinite speed.

jseah
2009-12-22, 04:28 PM
You could do one with portals of some kind, but at that point you could just use the "unlimited-use ring gates in a vacuum" trick to accelerate your bullet to infinite speed.
No ring gates please. I've created an NI drive with no moving parts using one pair. And a drive amplifier that'll move a moon from a Gust of Wind Box using 3 pairs.

They're also too high level.

Linear accelerators already require some pretty good timing. Circular accelerators would need a computer to time.

Johel
2009-12-22, 04:53 PM
In Ireland it would be "1,000.00" - are we not part of Europe? :smallamused:

...Damn, I'm tempted to say :
"-You are part of Europe but you're like the UK".
But then, given the "friendly" relationship between the Irishmen and the Englishmen, that can be misinterpreted. :smalltongue:

You are part of Europe but, as noted by another poster, the continent does things differently. Not better, not worse. Just different. Another example ? Which side of the road do you drive ? :smallbiggrin:

Storm Bringer
2009-12-22, 05:56 PM
So you have two types of shell.

One is a HE shell, for use vs airships as they have wooden (or soarwood) hulls. Shrapnel can rip a huge hole at the energies we're talking about.
The main problem in this shell is designing it to fragment not merely punch a hole through the target ship. (if you hit something metal, then you're lucky, but dense metallic things are rare on an airship)
The HE shell would have a large flat surface to increase area of impact and use something weak and cheap, like wrought iron, to increase chance of shattering and killing crew.
It'll also be heavy to reduce penetration but increase shrapnel. Doubling weight lowers speed by sqrt2. Taking your 2800ft/s = 853.44 m/s number for iron shattering for a target muzzle velocity at twice that, and the muzzle velocity estimate of 14 749 m/s for 1kg gives a shell weight of 149kg.

The anti-armour shell, for use vs castles and fortifications, would be light and shaped. Hardened Adamantine should do (DR 40 vs iron's DR 10).
Would need ballistics tests to get it right, but I'm guess the shell would be made to penetrate a few feet into stone, thus delivering most of it's energy in the middle of the wall for maximum effect.
EDIT: As it is, I can see even adamantine shattering if you just cover the Conductor Stone with it. Reduced weight needed.

Good, I'll use this gauss gun thing for the "end-game".

Any estimates on effective range? I think it could probably shoot 2 or 3 km since you're attacking from a height. Angling the ship would be a problem of course, since the 505ft long tube can't exactly be turned.

not bad ideas.

stone is brittle. and fails catastrophically, in that it goes from fine to broke with no inbetween stage. hit it hard enough, with a suitable protectile, and it will shatter and crumble. aim at the base of a wall and you will undermine it, making a breech. it will take a lot of shots to cause enough damage to make a practical breech (i.e. one that can be stormed), so we want somthing cheap. if we keep the velocity down, then simple steel will do, but we'd lose range.

A 1kg lump of lead at mach 43 would be.......intresting.

I have really no idea how that would turn out. Unlike stone, metals bend before they break if the shock is not too high. lead wouldn't shatter like steel, it's far too mallable for that. It'd either be super-effective and dump all it's energy onto the wall, causing heavy if shallow damage, or be useless and fail to effect the wall.

a 200Mj round optimised to penatrate would pass though....gods, tens of feet of stone, no problem. a 18MJ sabot round can punch though the equivilent of about 70cm (28 inches, just over feet) of steel, so i reckom thier is not a castle wall in exsistance that can stand up to this gun on full power.

Range, at full power, is effectivly limited only by targeting ability. While moving at mach 43 will cause some serious friction and loss of energy to heat (these rounds might be red hot when they stike home), your still looking at being able to toss these rounds many kilometers. the trajectory would be nearly flat, with little need to arc the shot. the biggest problem would be to manuver and hold the ship on target. agianst a immobile castle, you can sit back on horzion and lob away, but agianst another ship, your range goes down to a few km at best, depending on how agile the ships are and how easy it is to do precsion manuvering (as in, keep the bow on a bearing to within a single deggree of arc.)

the more accuratly you can point the ship, the longer your range is. best case, with magical spotters and a targeting computer, your looking line of sight, which could be up to 300km for a high altitude vessal.

Prime32
2009-12-22, 06:12 PM
the more accuratly you can point the ship, the longer your range is. best case, with magical spotters and a targeting computer, your looking line of sight, which could be up to 300km for a high altitude vessal.IIRC conductor stones emit light equivalent to a sunrod, so the cannon should have a built-in laser sight.

Storm Bringer
2009-12-22, 06:23 PM
useful, but it still reiles of being able to position the ship to a sutpidly precise degree (like seconds of arc precise for the 100K shots.)

also, I havn't considered atomspheric effects on the round. the best modern guns can put rounds in a CEP of 0.005% of the range, or about 5m per kilometer.

what that means is, at 100k, half your rounds are going to be hitting in a circle about 500m wide, with a 95% area about a kilometer across. this would if the target was perpendicular to the gun, but at that sort of range, your firing nearly paralel to the gound, so it would likey be much larger.


I don't think you could actaully hit anything at 100k without guided munitions.

jseah
2009-12-22, 06:29 PM
IIRC conductor stones emit light equivalent to a sunrod, so the cannon should have a built-in laser sight.
Not true.

The light's unfocused and not enough of it will return.

**************************************************

Storm Bringer:
Correction, the round is only 108MJ. I did make a calculation error above. This was stated in my edit so perhaps you did not get it.

43 times the speed of sound is correct however. Which is faster than escape velocity btw.

In any case, rounds will be heavier than 1kg and so travel slower than mach 43, and shaped adamantine warheads look like the way to go for thick ground targets. Rather than smash the outer wall, you could go through it and destroy the inside of the castle.

Then again, with the insane energy of the projectile, you don't have to worry about that. If the target's not sufficiently wrecked, just fire again. Gonna need spotters if you want to reliably know the target's condition though.
Can just imagine a covert mission. A capital ship is parked at 12 000ft, 3 kilometers to the east. Spies have to plant three flares set to go off at tonight, 1000ft to the north and south of the castle and one at the top of the tallest tower, in order for spotters to do a ranging calculation. Once the calculation is complete, the city comes under long range attack via railgun until the ship runs out of shells and returns home.

Storm Bringer
2009-12-22, 06:45 PM
at 3000 meters you are going to be clearly visable to the city.

plus, you don't need to place flares on the target to get the range. place two men known distance apart, with a preicsion method of mesuring angles.

volia, you have a co-incdence range-finder, good for ranging up to tens of miles. the more accruatly you mesure the angles, and the futher apart they are, the longer and better the ranging info will be.

to he honest, though, you don't need ranges, just bearings. high-power shots will have minimal bullets arcs, so it really just a matter of point and shoot

jseah
2009-12-22, 06:52 PM
Hmm. I see, by using landmarks (or signalling people), you can find out your current position on the map. Which can then be used to calculate distance to the target.

Well, this is why I'm not an artillery officer. XD Good to know these things. And certainly within the technology range of the setting.

EDIT: just read the article. It just determines range directly to the target. Not sure how, but hey... it works.

Prime32
2009-12-22, 07:17 PM
Wouldn't a spell like find the path or locate city tell you how far away your target is?

Here's an idea: what if you put this gun on a burrowing vessel and fired from below? (from the Underdark even :smalltongue:) The earth and stone in the way would slow down the projectile quite a bit (not to mention gravity) - would it have enough power to break through to the surface?

jseah
2009-12-22, 07:26 PM
You know I never really considered a sub-terra vehicle before. I just assumed it was impossible.

Is it? I'm not sure. Although airships will almost certainly be faster, so sub-terra vehicles would only be useful for mining and sapping buildings. Or undetectable strikes.

EDIT: find the path lays a path for you. Not a range finder.

Locate city tells you where the city is, but your projectile isn't powerful enough to destroy a city, only high priority targets within it.

Prime32
2009-12-22, 07:33 PM
Locate city tells you where the city is, but your projectile isn't powerful enough to destroy a city, only high priority targets within it.That's why you cast locate city twice. :smalltongue:

As for this:

The resilient sphere is probably the best trick, but as an alternative that punches great craters, how about giving the kingdom some way to cast over their soldiers Meld into Stone, and drop a large boulder down all the way to the target with catapults?

It puts some nice limitations, like just 100 pounds of non living gear, and some advantages, like allowing the subject to cast spells. Also, if the transporting rocks could be the source of the effect, being magically fortified to resist impact and desintegration, and allowing the guard members to meld with it, plus a teleportation effect like word of recall once per day that could be used over it to send it back to the base. And of course, the size of the rock could be a limiting factor to determine how much it could carry. And its size, weight, resistence and other possible shenigans could explain a lot of other uses, at GM discretion.Have a fiend of possession possess the projectile. If its momentum is so great that it can pass all the way through, have him ready an action to leave. If it's destroyed the fiend is unharmed, he just reverts to ethereal form next to it. And either way there is now a fiend of possession inside the enemy stronghold.

I'm just trying to think of some way you could generate a damaging aura around the missile so that everything in its path is affected...

EDIT: It would be tricky to pull off, but a prismatic sphere surrounding it would not only pierce nigh-anything, but it would blind anyone who saw it.

Otherwise there's the explosive runes bomb, the bag of holding that gets pushed into a portable hole on impact... maybe a contingent summoning spell?

jseah
2009-12-22, 08:04 PM
I don't understand how casting locate city twice would help. Mind explaining?

FOP:
Bit hard to qualify for that in 7 to 9 levels hey?

But it'll work well enough in a higher level environment.

That said, meld into stone should work. Catapult balls dropped from a balloon won't suffer too much damage, so the soldiers inside won't die. Well, wight-troopers that is.

jseah
2009-12-23, 09:20 AM
On the railgun:

Is it possible to have some kind of aiming device at the muzzle?

As in, placing a Conductor Stone in an anchor that can be adjusted, to deflect the shot as it comes out the muzzle. Let's it do small adjustments to aiming instead of moving the whole gun.

Might increase spread though, so it could be a tradeoff.

Radar
2009-12-23, 11:05 AM
If one really needs a rangefinder, then theese (http://en.wikipedia.org/wiki/Coincidence_rangefinder) are quite simple and effective, as long as there is a skilled craftsman around to build one. Since spyglass is mundane (albeit costly) equipment, there should be no problem, to build a coincidence rangefinder.

As for aiming with the railgun: to have any sort of long-range accuracy, while fireing from an airship, one needs IMO some decent stabilizing system (are gyroscopes too advanced for the setting?).
edit: forgot to add, that if one builds a stabilizer around the gun, then it's allready moveble to a degree, so no additional meassures are needed to aim the gun.

Prime32
2009-12-23, 11:32 AM
I don't understand how casting locate city twice would help. Mind explaining?It was a semi-serious suggestion to include a locate city nuke in the projectile. (use metamagic feats to make locate city deal damage to everything in its miles-wide area, then apply Explosive Spell)


As for aiming with the railgun: to have any sort of long-range accuracy, while fireing from an airship, one needs IMO some decent stabilizing system (are gyroscopes too advanced for the setting?).
edit: forgot to add, that if one builds a stabilizer around the gun, then it's allready moveble to a degree, so no additional meassures are needed to aim the gun.Well, there's always immovable rods (http://www.d20srd.org/srd/magicItems/rods.htm#immovableRod), though they would prevent the airship from moving while firing. It should be noted that the barrel is made out of force, so it shouldn't vibrate.

Lysander
2009-12-23, 11:56 AM
Alternate airship design:

Multiple flying carpets stitched together. For a one time price of of 240,000gp you can create a 40x40 platform that can carry either 3,200lbs or burdened carry 6,400lb (reducing move speed from 40 to 30). Sandwich the floor carpets between thin light layers of wood if you like to protect them from tearing, add a rail, chairs, a cloth canopy, any other improvements you want.

Perhaps a flying carpet deck could be part of a larger ship, the additional weight supported by a Wall of Fire balloon. The flying carpet part could be the "bridge" of the ship that tugs the rest along, providing highly controlled navigation and propulsion, and it could serve as an escape pod should the balloon ever be ruptured.

Trapped Gusts of Wind could act like rocket boosters to add additional speed. You would want two on each side of the ship, the four boxes made to rotate on command with permanent animate objects. When you want the ship to remain stationary you command the two boxes on each side to point in opposite directions to cancel each other out.

As a safety measure, why not have many immovable rods set up throughout the ship that you can quickly turn on to act as an anchor. That could stop a fall and also allow you to moor in place.

jseah
2009-12-23, 12:21 PM
Gyroscopes are fine. You'll need pretty good physics if you're going to create a timing system for the firing sequence.
Would also help in negating vibrations for anything else that needs aiming.

**********************************************

Locate City Nuke has to be casted from a caster right? And it's not like strange optimized strategies exist you know? =P

Immovable rods are cool for stabilizers as well. Like an expensive version of a gyroscope.

**********************************************

Lysander: carpets aren't worth it,
60 000 gp carries 1600lbs = 725kg
8 000+gp from gust of wind carries 230 odd kg
EDIT, sry 130kg

Gust of wind drives work better than carpets.

Lysander
2009-12-23, 12:32 PM
Lysander: carpets aren't worth it,
60 000 gp carries 1600lbs = 725kg
8 000+gp from gust of wind carries 230 odd kg

Gust of wind drives work better than carpets.

Except that the carpet obeys your spoken commands, allowing fine control, and can move in any direction. Gust of Wind may be cheaper, but it's more dangerous and you can't turn it off. It's basically like a rocket booster. What if the ship is just ten feet from where it needs to be? You can order the carpet to nudge the ship over, gust of wind will probably push it too far. Same goes for making turns. Tilting a gust of wind will quickly spin the ship, perhaps too far, ordering the carpet to turn the ship lets you have precise steering.

Which is why a good system uses both. Gust of Wind for extra speed and lift, carpets to make small navigational adjustments for you.

jseah
2009-12-23, 12:45 PM
Or you could dump the battle-platform idea and go for an airplane-style craft.

Carpets could be used for tugboats and such things to nudge objects.

Gust of Wind drives don't need to land. Just catch them with web between docking towers and then turn off the engine.

Radar
2009-12-23, 01:01 PM
Well, there's always immovable rods (http://www.d20srd.org/srd/magicItems/rods.htm#immovableRod), though they would prevent the airship from moving while firing. It should be noted that the barrel is made out of force, so it shouldn't vibrate.
Immovable rods do stabilize the gun, but you can't aim with an immobile object, so it's not usefull on it's own. They migh help with the recoil though. Also: vibrations are an issue only after you got rid of all the swinging and wobbling, which is inevitable on an airship.
Hmm... unless one immobilises a frame around the gun, so the gun itself could be rotated. That would be viable, but one has to remember, not to rig the frame tightly to the ship itself - hook it on steel lines or something (might be a part of recoil dampening system).

edit: immobilising the whole airship might require a tad bit too many rods.

jseah
2009-12-23, 01:11 PM
Immovable rods can support more weight then your drive can.

Having a pinned platform for The Gun is possible, with an airship chassis to attached move it around and point it in roughly the right direction.
Essentially, it'll be a flying cannon and not much else. Sounds good.

Storm Bringer
2009-12-23, 01:43 PM
pinning with the rods would help a lot, actaully. they'd allow you to keep on station when firing ultra-long range, provided you could attach a drive system that could move the agianst the rods to aim the ship (i.e. turn a few on, fine tune the aim, then turn them all on to lock on)

As for sums, don't forget that with magic, we have access to a totally reliable caluclator, somthing that wasn't around in our world until the last 100 years or so, so they can attempt maths that would have defeated RL people much eariler, as they can get the magic to crunch the numbers for them.

also, a lot of what we are talking about is engineering problems rather than theory problems. it's the sort of thing you hammer out with prototypes and such. building a recoil damper for the gun would require quite a few rebuilds to make it work, but trail and error would get you thier after a few goes.

jseah
2009-12-23, 02:14 PM
Would it be useful to build a short ranged version?

Initiator + 1 coil = 1.35 MJ output.

Could do for a ship-to-ship gun (or a ground-based cannon) since it'll be rotatable relatively easily. (only 10ft long)

Not sure if 1.35MJ is enough to do significant damage though.
A 1kg bullet *only* travels at 1647 m s-1 (or 4.8 times the speed of sound)

How far could you see this thing shooting? 1/2 a kilometer? 1?

Could it go through armour plate?

Lysander
2009-12-23, 03:35 PM
This is unrelated to propulsion, but you should really have the ship Hallowed as well. Annual buff of your choice for all on board.

jseah
2009-12-23, 04:01 PM
The Dimensional Anchor, if it prevents teleporting into the location, could be pretty useful.

If not, the next best is endure elements. Obivously for high-altitude flight. XD

Lysander
2009-12-23, 04:21 PM
The Dimensional Anchor, if it prevents teleporting into the location, could be pretty useful.

If not, the next best is endure elements. Obivously for high-altitude flight. XD

It wouldn't stop inbound travel, just outbound. Endure Elements is a good idea.

A really sweet combo: Permanent Web throughout the ship + Freedom of Movement through hallow. Your crew can move around without obstacle, intruders have to fight their way through constantly regrowing webs.

The Deej
2009-12-23, 04:36 PM
The ideas listed here for the "rail gun" are interesting, but a real rail gun in this sort of setting is far easier to construct, not to mention probably cheaper.

Rail guns are a form of linear motor. They're literally just two metal rails parallel to each other, and the projectile sits between them. A massive electric current is then sent through the rails (and projectile), which causes the projectile to be magnetically accelerated.

The biggest issue is that the magnetic forces also make the rails want to push apart, but magic can overcome this problem via walls of force or the like. The only other issue would be deciding on how to generate the electric current, but various 3rd or 4th level spells could be construed as capable.

Enough current could accelerate a projectile to ridiculous speeds, and would damage an area from sheer kinetic energy--think meteorite.

jseah
2009-12-23, 04:41 PM
You also need a magnetic field. A strong magnetic field. I don't see how to make one short of superconducting coils.

Electrical weapons are perfectly ok, lightning bolt wands will do. Magnetic fields? Not to so easy.

The Deej
2009-12-23, 04:48 PM
The magnetic field is generated by the electrical current. It's a law of physics that all electrical currents generate a magnetic flux. I'm an Electrical Engineering Technology major. I know how these things work rather well.

jseah
2009-12-23, 05:12 PM
Hmm... On reading the wikipedia article, that appears to be correct actually.

You are still subject to the problems our RL railguns face.

The conductive rails will burn out due to high voltage and friction with the accelerating projectile. Can't protect these with magic since wall of force rightly doesn't conduct electricity.

Problems:
Consideration has to be made to protect the system, that is likely to take up the large fraction of the system's cost.

Need some way to control temperature in the rails.
Need to protect crew from massive electrical current.
Wear on the rails needs to be repaired.
- Repair X line should do this

Power source and estimated energy:
Need an electrical source,
Electric sub. Wall of Fire
Lightning Bolt
Scintillating Sphere

Any others?

Also need a way to estimate energy output of those sources.
Note it takes much less energy to deal the same amount of damage with electrical currents than with heat.

The Deej
2009-12-23, 05:41 PM
rails can easily be repaired with mending/make whole or possibly repair X line.

temperature control is easy: chill metal

Protecting the crew from the current: the entire conductive part of the gun is either isolated or insulated from crew areas.

as for calculations of estimated energy, some quick searches found that the highest amount of power used in a rail gun is about 32 MJ, and a bolt of lightning can deliver 500MJ on average. If I am to trust the word of a friend who has been playing for quite some time and is consulted as the local rules expert, a call lightning spell summons a real lightning bolt, which would generate WAY more than enough power.

For an image, the firing would look something like this:
http://upload.wikimedia.org/wikipedia/commons/d/d3/Railgun_usnavy_2008.jpg

(Yes, this is a railgun firing. The fire is plasma in the projectile's wake)

jseah
2009-12-23, 05:50 PM
I think your friend is mistaken.

The spell works indoors and underground. No lightning bolts there.

Besides, 500MJ lightning bolt dealing only 3d6 damage? Not possible.

************************************************** ***

I don't think chill metal is going to be sufficient.

2d4 cold damage at the highest point isn't nearly enough to counteract the expected 3 or 4d6 of fire damage the heat should create after hardness.

Is there some kind of enchantment that can render an item immune to fire? That would solve the heat problems.

****************

I forgot about the wall of force casing. Yes, that solves the insulation problem.

************************************************** ***

I saw that picture on wiki.
I note that the 64MJ railgun is expected to deal the same kind of damage as a tomahawk missile.

The 108MJ Lightning Rail Cannon is then almost certain demolish anything it hits.

The Deej
2009-12-23, 06:15 PM
The chill metal thing actually came up in a game. The spell description doesn't say that it lowers the temperature, it says that it makes the metal cold to the point that it deals damage. Previous temperature doesn't matter. It could be just short of vaporizing and it's suddenly so cold that it harms anyone that touches it.

This only leaves us with the power issue. I'll agree that 3d6 doesn't sound like 500MJ of energy, but 3d6 will still kill a commoner outright.

lets see...1 ton of TNT equivalent is 4.184 GJ

dynamite (different from TNT) has 60% greater energy density than TNT

therefore 2000lbs/1.6 = 1250lbs of dynamite to output 4.184 GJ

1lbs. of dynamite is 3d6 as per DMG (p.146)

therefore 3d6 = (4.184*10^9)/1250 = 3,347,200 joules

So if 3d6 is approximately 3 MJ, to get that naval-equivalent railgun, we just need about 30d6 worth of electricity damage at once. I think that's doable somehow (even with something like 3 lightning bolts at once)

jseah
2009-12-23, 06:23 PM
As pointed out in the original magic as tech thread, you cannot just take damage as a direct relation to energy.

Firstly, energy, depending on type, deals damage in different ways. Fire damage is notably far higher in energy than physical. A longbow and arrow probably doesn't have much energy (kJs at most) and deals 1d6 damage while wall of fire outputs GWs of heat.

You need a lightning damage comparison. If you can find lightning damage dealt by a source we can estimate the energy of, and perhaps two examples of it, we can make a good estimate.

To use kinetic energy (from an explosion) is unwise.

The Deej
2009-12-23, 06:32 PM
that is a good point. Because that would mean that an average real lightning bolt would translate to 500d6 damage...

This could take a bit of searching.

jseah
2009-12-23, 06:56 PM
Right, sources I thought of:

Natural Lightning. I can't find rules for what getting hit by natural lightning does.

Electric Eel. Can't find that either. Maybe shocker lizards have the same thing?

Prime32
2009-12-23, 07:08 PM
I can't find rules for what getting hit by natural lightning does.IIRC it deals 10d6 damage.

jseah
2009-12-23, 07:11 PM
Let's see.

2 Shocker Lizards using 20ft range lethal shock deal 4d8 damage.
Let's assume this is the same as an Electric Ray (the most powerful electrical species).
Those have an output of 30 Amperes and a voltage of 200 Volts.

Over 6 seconds, this produces an energy of 36 kJ.

4d8 is a bit high for 36 kJ. Although wikipedia describes the discharge as similar to dropping a hairdryer into the bath. Which seems about right.

jseah
2009-12-23, 07:17 PM
Ok, I found it!

DMG pg 94

Each bolt causes electricity damage equal to 1d10 eight-sided dice.

Wow, that's the first time I've seen dice referred by the number of sides.

So it's 5.5d8 = 24.75 electric damage is one average lightning bolt or 500MJ.

That's actually... pretty low. Although it'll easily mash any low level character into the ground.

CL10 Lightning Bolt = 35 average damage = 606 MJ

That's... pretty damn amazing.

**************************

Wait a minute. The energy is spread over the entire stroke of lightning, but damage is for the bottom 5-8ft.

jseah
2009-12-23, 07:55 PM
Let's take the energy of 24.75 electric damage to be over the average height of a human in D&D = 5.75ft

According to http://www.wxdude.com/page5.html , which I'm not sure how reliable it is, the average path length of a lightning strike is 3 to 4 miles (we'll use 3.5 miles = 18 480ft)

5.75ft * 500MJ / 18480ft = 155 574 J or around 155 kJ to 24.75 damage over 5.75ft length.

So a lightning bolt, dealing 35 damage over 120ft, has an energy of 4 591 368 J, or around 4.6 MJ

The Deej
2009-12-23, 08:16 PM
so if one CL10 lightningbolt spell equates to roughly 4.6MJ, then eight of those (or equivalent) would power the railgun.

Now we just need a way to get 80d6 of electricity damage at once to produce the ~32MJ necessary for the railgun.

jseah
2009-12-23, 08:31 PM
Won't 80d6 electricity damage destroy your rails? =(

Lightning bolt hits objects.

And getting the bolt to turn around and come back through the projectile isn't going to go well. Lightning bolt goes in straight lines.

The Deej
2009-12-23, 08:39 PM
hence the "or equivalent". It just has to be 80d6. and they wouldn't be destroyed if they were large enough. They could also be made of adamantine. 80d6 is an average of 280 damage. Hardness reduces that to 260 damage, and Adamantine has 40HP per inch of thickness. If the rails were, say, a foot thick, then they could withstand up to 480 damage after hardness (a max roll of 80d6)

Chill metal, make whole/repair X, and you're ready to fire again.

jseah
2009-12-23, 08:46 PM
80d6 max = 480. Halved against objects = 240.

Adamantine + CL20 Hardening has hardness = 30. 210 damage = 5.25 inches of adamantine.

So build 6 inch diameter rails.

**working on design for abusing electrical conduction. Involves electric-sub fire wall and the "waves of heat/electricity".

The Deej
2009-12-23, 08:46 PM
Wait...to make a complete circuit of one electric current, would a chained arc of lightning work? (SpC p.15)

Prime32
2009-12-23, 08:50 PM
Meh, it's not as fun when it's powered by electricity. :smallamused:

The Deej
2009-12-23, 08:57 PM
Perhaps not a single gun in the context of a thought exercise, but the thought of "Wait, with my budget I can afford a whole friggin fleet of ships armed with these things? And each one can flatten the most heavily fortified castle in existence on its own?"

That's the fun of it.

ZeroNumerous
2009-12-23, 08:58 PM
Locate City Nuke has to be casted from a caster right? And it's not like strange optimized strategies exist you know? =P

You can make an item that casts the metamagicked version of the spell, or you could go one further and add Fell Drain to the nuke.

Using the magic item creation guidelines it'd cost 750 GP and 56 XP to create a single-use use-activated Globe of Locate City Nuke. The use to activate our globe will be smashing it. Now we make our delivery system, an Intelligent Continuously Invisible Continuously Flying +1 buckler. This costs 45,155 GP to buy or 22,577 GP and 1,806 XP to make. We now carefully place our Globe of Locate City Nuke into our buckler, give the intelligent buckler coordinates to bomb and it will fly to that location and drop it's Globe.

The resulting explosion will result in every level 1 jerk in a 70 mile radius to be converted into a wight.

As the reference goes: "The power to destroy a fortress pales compared to the power of the Magic."

The Deej
2009-12-23, 09:02 PM
Except for the questionable ability for locate city nuke to actually even work.

jseah
2009-12-23, 09:06 PM
Well, arc of lightning would work if you could target the rod you're firing as an object. And then make it come back to you. But I don't think Arc of Lightning is eligible for Chain Spell. It targets two creatures, not one.

That said, if we had a single creature target line of lightning spell, you could put a lightning immune construct as the projectile and one as the anchor on the other rail, then bounce the lightning from the source, down one rail to the projectile, and back the up the other rail to the anchor.

A bit hard to find one of those I think.

Failing that, you could rig up some system to cast Lightning Bolt down one rail and up the other in the opposite direction, and one more across the projectile.

*************************************

Deej:
Which was what I thought, since the Lightning Rail Cannon has a projected cost in the millions.

Zero:
Can we assume the Locate City Nuke doesn't exist? Or use the "it's a circle, not a sphere" interpretation?
Also, custom items are strongly discouraged.

ZeroNumerous
2009-12-23, 09:22 PM
Except for the questionable ability for locate city nuke to actually even work.


Zero:
Can we assume the Locate City Nuke doesn't exist? Or use the "it's a circle, not a sphere" interpretation?
Also, custom items are strongly discouraged.

Arcane Thesis'd Snowcasting Flash Frost Invisible Fell Drain Locate City. +3 adjustment with a -4 adjustment due to Arcane Thesis. 4th Level spell slot. Deals 2 cold damage to everyone in CL*10 miles(70 in this case). Everyone who takes damage gains a negative level. You become a wight when your negative levels = HD.

Being a circle does not affect it nor are there any questionable methods involved.

The Deej
2009-12-23, 09:23 PM
electric jolt (SpC 78) could be chained. But on the same page is electric loop, which already is capable of doing what I was looking for. Go figure.

@Zero: but because of the metamagic it has to come from a caster, not an item. It won't even work as an SLA.

ZeroNumerous
2009-12-23, 09:27 PM
@Zero: but because of the metamagic it has to come from a caster, not an item. It won't even work as an SLA.

There are weapon enhancements that Empower spells cast into them(bloodstone) and a scroll can cast a metamagicked version of a spell just fine. It is 100% viable and requires no caster.

jseah
2009-12-23, 09:30 PM
Electric Loop works. Only you need to consider the two rails, the projectile and the anchor as creatures (animate objects will do here, permanency for that is expensive, but worth it if there's no other way)
- Note, the objects are adjacent if they occupy adjacent squares. In contact counts I guess.

You also need to soup up the damage. 5d6 isn't enough by 16 times. Many many wands of it and a sort of trigger mechanism? Or multiple operators readying actions to UMD.

The Deej
2009-12-23, 09:47 PM
Concerning locate city nuke:
Still not convinced, but anyway, the OP is saying no to it regardless of interpretation, so this is moot.

Concerning electric loop:
Perhaps wands that can all be triggered at once via command word or something? 16 of them all into the same targets in the same order will do it. Kirchhoff's current law says so.

jseah
2009-12-23, 10:06 PM
Wands aren't command word. Is there a way to trigger multiple wands with one guy?

Dual Wand Wield cuts down the number of operators to 1 bard, 1 artificer and 7 guys with UMD. Plus a wand of make whole.

The Deej
2009-12-23, 10:18 PM
the rod of many wands (CM 128) might help, were it not so high CL. Three wands at once via command word. Doesn't say that it needs to be held to be activated. Five of them all linked to the same word would make this incredibly easy. But it says Cl 17. We'd probably have to go with just multiple operators all with readied actions.

Slayn82
2009-12-26, 08:11 AM
Well, how about an electric altered FIREWALL?

We know from the spell descriptions that both Fireball and Lightning Bolt

"can melt metals with a low melting point, such as lead, gold, copper, silver, or bronze"

so this suggest both effects are realizing work somewhat around the same orders of magnitude.

Now, based on this, we could argue that both versions of Wall of Fire spell (fire based and electric based) produce energy somewhat in the same order.

The advantages are obvious, now we are allowed to choose the path that the current will pass throught the conductor (Walls of Iron, somewhat easily replaceable?). Just cast the SPARKWALL over the metal conductor, making sure you adjust that in the direction of your target. Between True Strike and Locate City, and Clarevoyance a few miles high for eagle eye observation of the projectile trajectory, and you have a very efficient weapon. With an absolutely scary range.

-----------------

Just a few ramblings

Reading about Jack Vance, whose magic sistem inspired D&D, it makes a lot of sense. Magic was created for very advanced purposes, but after the fall of civilization, a lot of knowledge was lost, and so spells started being used for their apparent purposes, instead of their intended ones.

And so, mages in D&D look at this spell, sighs, an then go memorize something more "usefull".

Remember the trouble with the excess energy, and the risk of the boillers overheating and exploding? How it was important to dump all that heat?

Well, how about heating a lot of excess water from a river (for land based instalations, decanter of endless water got nothing against a river in water flux). And then, with a few Move Earth and Transmute rock to stone spells, and you have your own Hot Park/Hot Springs/Club/Pool. How about that? Thermal Waters, yoho!

The Deej
2009-12-26, 09:11 AM
The main issue with a SPARKWALL as you suggest, is that the work is done over too long a span of time. What's needed is a millisecond burst of it all at once. If you can think of a way to delay it all to hit at once, then that would work.

As I was typing this, something hit me: Delay Spell. Duh. a bunch of delayed anything electric all timed to go off at once will produce the desired effect.

Johel
2009-12-26, 09:38 AM
Isn't the biggest problem of a true railgun to make the magnetic field "move" ? I know I'm not using the correct terms but, basically, for the projectile to accelerate, the magnetic field must "progress" (more power forward, less power backward) along the rail at a steady pace, not simply power up on the whole rail. If it doesn't progress, then the projectile will just hover on its initial spot, like if it was surrounded by fixed magnets.

If the SPARKWALL appears progressively along the rail, that might work.
But if it simply jump to life at once on the whole length, then that won't work.
Or maybe I didn't get what you meant...:smallfrown:

For the rambling :
Wouldn't water kinda ruin the purpose of using an electricity-based boiler ?
Iron conducts electricity but so does water.

Hot springs :
There we go !!
THAT can work and no catgirl will be harmed !! :smallsmile:
The FIREWALL heats the boiler's pipe, the water takes the heat away, and the pool collects the heated water, keeping us warm and wet.
Humm...

jseah
2009-12-26, 02:12 PM
Deej: Great idea. Delay spell will thus be used for timing mechanisms and reduce operator count to three. Artificer with UMD plus two dudes with UMD.

Johel: The railgun will work even with a constant current and constant magnetic field. DC current will generate force in a magnetic field.

While hot springs is a good idea and definitely something to include for the high-class, something more substantial is needed in order to define the setting, regardless of the catgirl body count.
Railguns, floating towers (perma wall of force), airships and steam engines work very well in doing this.
Still, I'm snitching the hot springs idea.

IMO, a true magic as tech setting would have more differences than merely some factories, mundane magic and high-powered cannons.
A true tone shift is needed.

Instead of a threatened idyllic rural kingdom or a majestic towered city like in LOTR, there needs to be a sense of... implacableness. A sense that in using magic as technology, something bigger than people has been created. People can die, countries can be conquered, but magic technology is here to stay. Not even heroes can change that, for civilization as a whole is larger than the sum of it's parts. You can raze the cities to the ground but the ideas, the images, will stay in people's minds and if there's anyone remaining, it'll be rebuilt again.

I was thinking about things like universities and compulsory education. A welfare system where everyone gets an Everlasting Ration and pays back the government in taxes. Water pipes running everywhere, and houses going for less than an everlasting ration (lyre of building). Actual democratic government system.
A nearly insurmountable social divide, in a post-scarcity economy. National projects built at a whim of some rich person. Poor people slaving away at service sector jobs.
Insanely overconfident mindset. Magical beasts, disorganized monsters, uncivilized sentient creatures, are forcefully inducted into the civilization under the guise of making a better life for them. Beasts reared for their special products (eg. Steelwings, MM5, for adamantine) and use in material components. Lawful Good society on the surface, with angels and archons asked to pass judgement, but in fact highly biased towards humanoids (due to drawing those angels from the humanoid races' gods)

And there's nothing to be done about it. The magic technology makes the society the most powerful force in the universe (or it wouldn't be that kind of setting) and it's more than what a few young idiots (aka. PCs) can do anything about.