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Gavinfoxx
2010-11-28, 05:18 PM
Okay, I heard a story that someone figured out that if you put a Decanter of Endless Water on Geyser, and put it through a Riverine Tube that ended in a 1" Diameter nozzle, and on it's way through the tube, it went through some type of Rune or Glyph that changed the water into steam, you end up with half the thrust that the Space Shuttle makes? Does anyone know more about this trick, and where that rune / glyph comes from? I don't actually have the source for this part of the trick. Does anyone also have the post that talks about the math for this?

Edit: Okay. The rune comes from SOME Dragon Magazine... now the question is, which?

AstralFire
2010-11-28, 05:28 PM
Heh, been trying to help you find it and every result I find on the subject is you. XD

Fouredged Sword
2010-11-28, 05:33 PM
That would depend on the rate of transfer of energy from the rune to the water, and the final temperature of the water. You would get little thrust if the water just condensed back into liquid at the end of the jet. You need a gas pushing back on the surface to create the pressure diferential. If the water condensed as the pressure droped the change in volume of the gas//liquid mix would decrease the thrust potentialy quite a bit. If the gas was hot enough to remain steam through the whole event, then a considerable thrust could be gained by the constant addition of energy and mass.

Gavinfoxx
2010-11-28, 05:35 PM
Heh, been trying to help you find it and every result I find on the subject is you. XD

ARGH.

That would depend on the rate of transfer of energy from the rune to the water, and the final temperature of the water. You would get little thrust if the water just condensed back into liquid at the end of the jet. You need a gas pushing back on the surface to create the pressure diferential. If the water condensed as the pressure droped the change in volume of the gas//liquid mix would decrease the thrust potentialy quite a bit. If the gas was hot enough to remain steam through the whole event, then a considerable thrust could be gained by the constant addition of energy and mass.

Well let's take the basic premise: Decanter set to geyser, a rune that changes all water over it to steam, and a Riverine chamber holding the rune, ending in a nozzle. How well would that work? Would the chamber also need to be heated with a Wall of Fire effect in it somehow? If you had both the rune & the wall of fire effect, would that work better?

nedz
2010-11-28, 07:05 PM
All you really need to do is add enough heat and the water will turn into steam of its own accord. The RAW does not cover the thermodynamics of Wall of Fire, or indeed anything else, in enought detail to work out if that would be sufficient.

For optimum effect you would need to design the nozzle correctly.

I take it your character has many ranks in Knowledge (Rocket Science) ?:smallbiggrin:

Jack_Simth
2010-11-28, 07:19 PM
All you really need to do is add enough heat and the water will turn into steam of its own accord. The RAW does not cover the thermodynamics of Wall of Fire, or indeed anything else, in enought detail to work out if that would be sufficient.

For optimum effect you would need to design the nozzle correctly.

I take it your character has many ranks in Knowledge (Rocket Science) ?:smallbiggrin:

If he's actually trying to build the thing, he needs Craft(Rockets).

oxybe
2010-11-28, 07:28 PM
which is frightening in that the character is able to willingly build something he has absolutely no understanding of...

IthilanorStPete
2010-11-28, 07:59 PM
^ a thread that covers this kind of thing.

Jack_Simth
2010-11-28, 08:13 PM
which is frightening in that the character is able to willingly build something he has absolutely no understanding of...
How do Sorcerers, Favored Souls, and Clerics cast spells, again? Unlike the Wizard, they have absolutely no necessity of picking up Spellcraft, Knowledge(Arcana), and Knowledge(Religion)....

Mando Knight
2010-11-28, 08:55 PM
Okay, I heard a story that someone figured out that if you put a Decanter of Endless Water on Geyser, and put it through a Riverine Tube that ended in a 1" Diameter nozzle, and on it's way through the tube, it went through some type of Rune or Glyph that changed the water into steam, you end up with half the thrust that the Space Shuttle makes? Does anyone know more about this trick, and where that rune / glyph comes from? I don't actually have the source for this part of the trick. Does anyone also have the post that talks about the math for this?

I don't have a previous post that covers this, but the designer of this system quite frankly has almost nothing in Knowledge (Rocket Science). If you've got a source of "free" heat addition like a fire spell, you might as well use Rayleigh-Fanno flow properties to get a tube of length L* to choke the flow (using a system with high-pressure steam) and then add a diverging nozzle to isentropically expand the flow to get a higher exhaust speed.

And, honestly, you'll need to use thermodynamic properties to ramp up the thrust: a 30-gal/round decanter only hits around 19 kg/s mass flow rate, while the average mass flow rate of the SSME assembly is approximately 1528 kg/s.

I mean, if you can get your energy input rate and starting conditions (pressure, temperature) for the steam, it's a fairly simple compressible flow problem. Which is really all that rocket science is.

Gavinfoxx
2010-11-28, 09:07 PM
Eh, there are spells that can arbitrarily get you any appropriate knowledge you need, in order to design this thing..

Also, I would REALLY like to know the source of that rune! really!

Kelb_Panthera
2010-11-28, 09:29 PM
I found the reference to getting orbital velocity from tightening the stream on the last post of the thread linked by IthilanorStPete. According to that poster's math, you'd need to tighten the nozzle down to 2mm.

JaronK
2010-11-28, 09:33 PM
If it helps, I was part of the thread that originally came up with this. It was on the Gleemax boards, and a guy was asking about the best vehicle for his bard in a campaign. Then he signed off. In the next 24 hours, we had figured out how to make a space ship that could travel extremely fast, had atmospheric controls, shields that could withstand crashing straight through a planet, and artificial gravity. Then the guy posted again to say he meant a carriage or something.

Some people are just far too unspecific.

Anyway, the rune was mentioned by name in that thread.

JaronK

Mando Knight
2010-11-28, 09:42 PM
I found the reference to getting orbital velocity from tightening the stream on the last post of the thread linked by IthilanorStPete. According to that poster's math, you'd need to tighten the nozzle down to 2mm.He's wrong. Water can't behave as an incompressible substance at that high of pressure (~19 kg/s through a ~0.00000314 m^2 hole with 1000 kg/m^3 density? Yeah... no.), so the flow is going to get choked (read: speed will be stuck at Mach 1, density will spike, temperature will grow much more slowly) long before the nozzle goes down to 2mm diameter. There's a reason the shuttle main engines have those gigantic flaring nozzles. It's to accelerate the flow. I'd explain better, but that's what classes in gas dynamics are for. :smallamused:

JaronK
2010-11-28, 09:45 PM
But remember, you've got a magic rune that just makes stuff steam regardless of what else is happening. So the steam, when under intense pressure, still can't go back to being water or anything... it magically keeps enough temperature and force and whatever to keep as steam and pushes back. So, it could be a bit different here.

JaronK

Mando Knight
2010-11-28, 10:55 PM
But remember, you've got a magic rune that just makes stuff steam regardless of what else is happening. So the steam, when under intense pressure, still can't go back to being water or anything... it magically keeps enough temperature and force and whatever to keep as steam and pushes back. So, it could be a bit different here.
Doesn't matter. The principles hold valid for a thousand kilos/sec of steam at a thousand or two Kelvin (that is, the SSME), they'll hold for less than 20 kg/s at maybe 500-700 K (that is, around 400-800 F).

The Glyphstone
2010-11-28, 11:10 PM
Wait, so now finding ways to abuse RAW is rocket science?:smallbiggrin:

JaronK
2010-11-28, 11:15 PM
Damn right it is. I remember that one of the things we figured out was that the steam would necessarily be at absolutely ridiculous temperatures to actually blast out. Remember, it has no choice but to go out at that speed. It can't go anywhere else. The Riverine is indestructible, and the magical decanter pushes a specific amount of water out no matter what. The rune magically forces it to be steam.

The amount of magic in this really messes with normal rocket science principles. There's no way for the flow to decelerate, regardless of the width of the aperture or anything else. You end up with super hot steam being pushed out at a ridiculous rate... this also resulted in us figuring out how to make a recoiless rifle using a very similar technique that launched projectiles fast enough to do about 5k damage (using the falling rules as a guideline for how much damage is achieved at what speed) in addition to a super hot steam gun (damage undefined).

JaronK

oxybe
2010-11-28, 11:22 PM
actually, nowhere does it state a wizard actually needs knowledge of the arcane or spellcraft to cast his spells...

hm...

i'm getting a idea for a character...

:3

Darius Rae
2010-11-28, 11:23 PM
Anyone got the specific impulse for a Decanter of Endless Water on geyser?

Edit:
Step One: Energize the water from the Decanter until it separates into hydrogen and oxygen
Step Two: Allow the hydrogen and oxygen to recombine
Step Three: ???
Step Four: Profit

Infinite energy via spells should make this possible

Elfstone
2010-11-28, 11:32 PM
If it helps, I was part of the thread that originally came up with this. It was on the Gleemax boards, and a guy was asking about the best vehicle for his bard in a campaign. Then he signed off. In the next 24 hours, we had figured out how to make a space ship that could travel extremely fast, had atmospheric controls, shields that could withstand crashing straight through a planet, and artificial gravity. Then the guy posted again to say he meant a carriage or something.

Some people are just far too unspecific.

Anyway, the rune was mentioned by name in that thread.

JaronK
Can you link me to this thread? I gotta see this for myself.

Kelb_Panthera
2010-11-28, 11:57 PM
actually, nowhere does it state a wizard actually needs knowledge of the arcane or spellcraft to cast his spells...

hm...

i'm getting a idea for a character...

:3

while you don't need Know(arcane) to be a decent wizard, you emphatically do need spellcraft. Without being able to make a decent spellcraft check you won't be able to add new spells to your book, which will leave you with a mere 4/spell level.

oxybe
2010-11-29, 12:01 AM
doesn't stop you from still having 4 spells per level though!

Mando Knight
2010-11-29, 12:08 AM
Anyone got the specific impulse for a Decanter of Endless Water on geyser?
Depends on the temperature of the water, and how much additional heat you add to it, and the throat-nozzle area ratio.

Step One: Energize the water from the Decanter until it separates into hydrogen and oxygen
Step Two: Allow the hydrogen and oxygen to recombine
That's just heating the water. You're trying to use thermodynamics to break thermodynamics, which doesn't work.

Darius Rae
2010-11-29, 12:22 AM
Except D&D breaks thermodynamics...

Using a spell you separate the oxygen and hydrogen, the real world analog would be electrolysis. You then allow the oxygen and hydrogen to recombine in the same manner of liquid fueled rockets.

You do not actually save any energy, because you expend the same amount you put in, but because you magic the energy in, you get "free" energy in the system. Basically, It only works because you use magic...

To clarify why you want the oxygen and hydrogen to recombine... It is because if you force liquid oxygen and liquid hydrogen together, you get the same reaction that fuels the space shuttle

Mando Knight
2010-11-29, 12:32 AM
Using a spell you separate the oxygen and hydrogen, the real world analog would be electrolysis. You then allow the oxygen and hydrogen to recombine in the same manner of liquid fueled rockets.

You do not actually save any energy, because you expend the same amount you put in, but because you magic the energy in, you get "free" energy in the system. Basically, It only works because you use magic...

You could have used the exact same energy to just heat the water. Same effect, one action. Yes, there'll be some dissociation and recombination in the steam, but that's because of the equilibrium concentrations at the higher temperature. You're just wasting time if you split the hydrogen and oxygen to just immediately recombine it again. Unless the spell that specifically causes hydrolysis/electrolysis of the water is more efficient to cast than a spell that causes the same amount of energy addition in the form of heat, you're just as well off adding the heat directly to the water.

Tvtyrant
2010-11-29, 12:36 AM
I think the easiest thing to do would be to have a gate to the Plane of Water on the bottom of your ship, and then have a Maximized Hellfire Firewall thrown across the opening of it. The gate and firewall would be inside of an adamant barrel, and would have a very small nozzle that flares at the bottom. You would have an almost infinite amount of water pouring in under incredible pressure and then being flash boiled at thousands of degrees.

Mando Knight
2010-11-29, 12:46 AM
In short, the SSME, built using magic fuel and heat addition rather than LOX/LH2, and adamantine rather than exotic ceramics and metals. The throat-exit area ratio on the SSME is also something like 1:100, so the nozzle wouldn't exactly be small... (as per a cursory examination I made early this month at Kennedy, looking at the display model of the SSME and taking eyeball measurements of the throat and nozzle exit)

IthilanorStPete
2010-11-29, 12:50 AM
In short, the SSME, built using magic fuel and heat addition rather than LOX/LH2, and adamantine rather than exotic ceramics and metals. The throat-exit area ratio on the SSME is also something like 1:100, so the nozzle wouldn't exactly be small... (as per a cursory examination I made early this month at Kennedy, looking at the display model of the SSME and taking eyeball measurements of the throat and nozzle exit)

It's actually about 1:9, according to Wiki - 10.3 inch diameter at the throat, 90.7 inch diameter at the nozzle exit.

Tvtyrant
2010-11-29, 12:51 AM
By our powers combined, we have created a spaceship! Go Planet!

Actually, it would be kind of cool to make a high to epic level spelljammer campaign using this; high level using steam-ship, epic by just creating an extended Reverse Gravity or permanent one.

Gavinfoxx
2010-11-29, 01:34 AM
If you all could help me with the name of the thread, or the thread number, I would be able to find it on Internet Archive!

If it helps, I was part of the thread that originally came up with this. It was on the Gleemax boards, and a guy was asking about the best vehicle for his bard in a campaign. Then he signed off. In the next 24 hours, we had figured out how to make a space ship that could travel extremely fast, had atmospheric controls, shields that could withstand crashing straight through a planet, and artificial gravity. Then the guy posted again to say he meant a carriage or something.

Some people are just far too unspecific.

Anyway, the rune was mentioned by name in that thread.

JaronK

Can you help me find that thread, either the title, a few words of the title, or the thread number, or something like that somehow? I would be REALLY thankful...

jseah
2010-11-29, 03:16 AM
I remember I did some calculations with a wall of fire + decanter. On this board too. A de laval nozzle IIRC.

Of course, auto-flashboil rune is better than a few MW of heat. So I'll like to see how that works.

That said, do you really need a rocket? Reactionless drives are much better. You can build a spring powered one with ring gates.

Yes, spring powered.

Gavinfoxx
2010-11-29, 03:21 AM
I remember I did some calculations with a wall of fire + decanter. On this board too. A de laval nozzle IIRC.

Of course, auto-flashboil rune is better than a few MW of heat. So I'll like to see how that works.

That said, do you really need a rocket? Reactionless drives are much better. You can build a spring powered one with ring gates.

Yes, spring powered.

Could you elaborate on this? I found a dragon magazine article that talked about Runes in general, but it didn't say anything about a water to steam rune. Is the water to steam thing a normal spell applied to a rune, or a SPECIFIC, written up Rune?

JaronK
2010-11-29, 03:30 AM
Can you help me find that thread, either the title, a few words of the title, or the thread number, or something like that somehow? I would be REALLY thankful...

Sorry, that was all I can remember. It was years ago, they may have deleted it by now. I know every detail of how to make the ship except where the rune was from.

JaronK

Gavinfoxx
2010-11-29, 03:35 AM
Sorry, that was all I can remember. It was years ago, they may have deleted it by now. I know every detail of how to make the ship except where the rune was from.

JaronK

Oh I'm quite sure they've deleted it, that's why I want to find it on web archive... Do you remember if the rune was simply using a spell in a specific type of rune that you put a specific spell in, or a particular writeup of a specific rune that does this? The only Rune stuff I can find is the Gothic II stuff from Dragon 324, and that just lets you put spells into runes... so the question is... if that is it, what is the spell and where is it??

JaronK
2010-11-29, 04:35 AM
I have absolutely no idea on the details of the rune.

JaronK

Nyarai
2010-11-29, 04:47 AM
This got linked on the WotC boards a few years ago, which I found when I searched for "spaceship decanter of endless water."

http://boards1.wizards.com/showpost.php?p=7804909&postcount=32

It redirects me to their mainpage, but hopefully you can work some internet magic or something. :smallwink:

kestrel404
2010-11-29, 06:01 AM
This got linked on the WotC boards a few years ago, which I found when I searched for "spaceship decanter of endless water."

http://boards1.wizards.com/showpost.php?p=7804909&postcount=32

It redirects me to their mainpage, but hopefully you can work some internet magic or something. :smallwink:

I opened that thread on the wayback machine. It's not the thread you're looking for. But there IS instructions for building a spaceship in it. I'll post it here:

This is a brilliant way to get a LOT of power. I'm assuming that Tyrany works the same as Leadership, since I don't have 7th Sea. I'm also assuming that you're not using hte Wealth system, and are instead using the good-old GP/credits system. (I'll be calling them GP for simplicity's sake.) For the sake of SOME balance, Extra Followers will only apply to ONE Leadership. And finally, I don't think Competence bonuses stack, but that's okay. I am, however, assuming your DM will see the sense in letting your sidekick and your cohort's bonuses stack, sinse it's sharing of expertise and by definition they have different expertise.

THE CHARACTER AND HIS HELPERS

The Character

First, you are any evil human -- probably lawful evil. Max out INT and CHA. At the expense of EVERYTHING. CHA needs to provide as close to +9 as you can get, and INT needs to go as high as it can.

Classes:

Smart 10/Exemplar 1/UA Expert 4/UA Warrior 4/X 1//Cleric 1/Marshall 1/Wizard 17

Your domains are Artifice and Craft, and your Skill Mastery is Craft (Mechanical). For Warrior and Expert, your skills include Craft (Mechanical) and Diplomacy. Aura is Motivate Intelligence.

Feats:

Level 1: Artistic Crafter (Craft [Mechanical]), Engineer

In whatever order you prefer, barring prerequisites

Skill Focus (Craft [Mechanical])
Master Crafter
Tyrant
Minions
Sidekick
Extra Followers
Skill Emphasis (Craft [Mechanical])
Handy
Mercantile Background (Craft [Mechanical])
Ordinary Past
Student of the Arts (Craft [Mechanical])

This leaves you with an outrageous number of bonus feats from Smart. Take whatever you think would be helpful.

The Cohort:

Classes:

Human UA Expert 4/UA Warrior 8/UA Spellcaster 1/Field Marshall 5//Marshall 1/Wizard 17.

Background is Dillente, or whatever that +6 to Rep one is. Skills are Diplomacy and Knowledge (Tactics). Aura is Motivate Intelligence.

Feats:

Skill Focus (Craft)
Personal Firearms Proficiency
Fame x 14

EDIT #2A: The Sidekick:

Classes:

Human UA Expert 4/UA Warrior 8/UA Spellcaster 1/Field Marshall 5//Marshall 1/Wizard 17.

Background is Dillente, or whatever that +6 to Rep one is. Skills are Diplomacy and Knowledge (Tactics). Aura is Motivate Intelligence.

Feats:

Skill Focus (Craft)
Personal Firearms Proficiency
Fame x 14

EDIT 2B: Followers/Minions:

Your followers are all Human. In the case of your undead followers, they all have the Corpse template.

Classes:

Their classes, depending on their levels, are below. In parentheses is the number of each you get, assuming a Leadership score in each of 25.

Level 1: UA Expert 1 (540)
Level 2: UA Expert 2 (52)
Level 3: Dedicated 3 (28)
Level 4: Dedicated 3/UA Expert 1 (16)
Level 5: Dedicated 3/UA Expert 2 (8)
Level 6: Dedicated 5/UA Expert 1 (8)

In the case of Dedicated, they all take Empathy, then Improved Aid Another, then Improved Aid Another. Skills always include Craft (Mechanical). All skill points are spent on bringing it up to highest rank for that level. Obviously, this means the Expert levels are taken last.

Feats:

Feats in parentheses are to be taken after the first two.

Mercantile Background (Craft [Mechanical])
Skill Emphasis (Craft [Mechanical])

(Skill Focus [Craft (Mechanical)])
(Master Crafter)
(Builder)

If the follower is a Dedicated 3, substitute Cosmipolitan (Craft [Mechanical]) for Mercantile Background.

PROCEDURE, PART ONE

Every second of your and your lackeys' spare time is dedicated to making money. A good way to do this, once you, your cohort and your sidekick can cast flesh to salt (and later mass flesh to salt) is to get cows, change them into salt, and sell the salt for the going price. Your lower-downs can make wind-up toys or something.

The point of this is to get...

Brace yourself...

19 million GP.

Yes, THAT much. Please pick up your jaw; with enough lackeys working around the clock, it's doable. And trust me, you have enough lackeys

Besides, you're never gonna really be buying any, you know, EQUIPMENT or anything, aside from stat-boosting items. Just tell your party to wait and see, and have good faith.

Or just show them this build, whichever.

PROCEDURE, PART TWO

Now, you have 19 million GP. But what to DO with it? The answer:

Spend every copper of it on raw materials.

Once you've done that, here's what you do: go to a plane where time goes very, very fast in comparison to the Material Plane.

EDIT #2: I have found a way to cut down on this time even MORE by adding the Minions and Sidekick feats from d20 Past. I am assuming that Field Marshall bonuses from two sources stack, because it makes sense game-wise. Your DM results will vary.

Every day, this is your procedure:

--You, your cohort and your sidekick cast fabricate until both of you run out of spells.

--All three of you activate your Motivate Intelligence auras.

--You announce your Craft (Mechanical) check.

--Your cohort and your sidekick use their August Leadership ability to add 48+CHA (Rep+CHA) to your check. (They don't fail this because he's got at least 9 ranks in Diplomacy.)

--All of your first and second level followers Aid Another you, for (assuming your Leadership, Tyrant, Minions and Undead Leadership scores are all at least 25) a +1480 bonus on the check. (Note: None of your follower's checks fail, because their feat bonus is at least +5, plus at least four ranks in Craft [Mechanical]. Add in the 1 from the lowest possible roll, and they get a 10.)

--All of your third and fourth level followers Improved Aid Another you, for (again, assuming scores of 25) another +165.

--All of your fifth and sixth level followers Improved Aid Another x2 you, for another +80.

--You take 20, thanks to Artistic Crafter.

23 Ranks
Taking 20, Artistic Crafter
+1d4, Handy
+2, Skill Focus (Craft [Mechanical])
+2, Master Crafter
+3, Skill Emphasis (Craft [Mechanical])
+2, Mercantile Background (Craft [Mechanical])
+2, Ordinary Past
+2, Student of the Arts (Craft [Mechanical])
+Cohort's CHA mod, cohort's aura
+Cohort's CHA mod, cohort's August Leadership
+Sidekick's CHA mod, sidekick's aura
+Sidekick's CHA mod, sidekick's August Leadership
+80, followers' Improved Aid Another x2
+165, followers' Improved Aid Another
+1480, followers' Aid Another
=
+1917 total check result.

Now, the difference in Craft DC between a wooden spoon and a jet engine is 25. As such, me and a fellow player/DM decided that the magnitude of complexity from a wooden spoon to a jet engine (DC 30) is about the same as from a jet engine to our target object. The conversation is funny enough to be repeated below.

Me: Would you say that the difference in magnitude between crafting a spoon and crafting a jet engine is abut the same difference in magnitude between crafting a jet engine and crafting, say, a __________?

Me: A wooden spoon, mind.

(pause)

Me: Yes, I know it's stupid, shut up.

Her: hm.

Her: i would say not quite as magnificent.

Me: ...

Her: at least the jet engine and the _________ have the same basic mechanics involved.

Her: A WOODEN SPOON, TUCKER.

Me: No, no, no, we're talking degrees of complexity here.

Her: oh.

Her: then yes.

Me: Okay.

Anyway, we decided that an acceptable Craft DC was 55. If your DM says it's higher, hey, even better; it just means the work gets done faster.

So. 1524 times 55 equals 83,820. Not counting fabrication, you'll get 8,382 GP worth of work done in a week. Of course, this will still take 130 years not counting fabricate. Nihility found the solution to the problem: voluntarily increase the DC of the target item until it equals 1515. That's an increase of 1460, if you care. Anyway, that means you get 230,886 GP done in a week -- so this'll take you about 4 and 3/4s of a year.

EDIT #2: But then, that's the OLD number. Since our NEW check is +1917 (or 1917-48-sidekick's CHa mod, if the field marshall bonuses don't stack) we can crank that DC up to 1915. So, 1917 times 1915 is 3,671,055, which adjusted and rounded down is 367,105 GP per week, cutting your time down to JUST under three years. HUZZAH!

So anyway, let's assume you do all that. What do you get?

WHAT YOU GET

http://www.theforce.net/swtc/Pix/books/egvv/vsd-eg1.gif

That's right. A Vicstar. (Victory-class Star Destroyer.)

Have fun with your new implement of destruction. And remember: it looks real good with a planeshifting helm on it.

SOURCES

Feats: Crystalkeep d20 Feat list (it's listed under 3.0, but has an "everything from d20" option.)
Minion and Sidekick Feats: d20 Past
Expert, Spellcaster and Warrior: Unearthed Arcana
Marshall: Miniatures Handbook
Smart, Dedicated, Dillente background: d20 Modern Core Rulebook
Field Marshall: d20 Future
Flesh to Salt: Sandstorm
Victory-class Star Destroyer: Starships of the Galaxy
AllistairAldred
11-21-05, 04:27 AM
Wow. The possibilities for this are UTTERLY RIDICULOUS. I am too tried to really think of anything right now, but ill get back to you probably tomorrow, with some creation. although the jedi//Dervish idea is pretty awesome.... Wow...i just have to say that if one of my DMs did this i would crap a gold brick...

Elfstone
2010-11-29, 06:25 AM
I opened that thread on the wayback machine. It's not the thread you're looking for. But there IS instructions for building a spaceship in it. I'll post it here:

*Jaw drops*
*fumbles around on the ground, picks up jaw, returns to correct position*
Sadly most DMs would view this much like punpun..

AstralFire
2010-11-29, 06:42 AM
I actually rate it below Pun-Pun. It's very silly and strings together multiple d20 systems which, while related, are not compatible. 'tis amusing though.

jseah
2010-11-29, 07:24 AM
This is probably a shameless plug since these are my calculations...

<Math warning>
Here you go about wall of fire:

The thread linked below contains a number of calculations about the energy output of wall of fire.
http://www.giantitp.com/forums/showpost.php?p=7499319&postcount=29
http://www.giantitp.com/forums/showpost.php?p=7500548&postcount=37
http://www.giantitp.com/forums/showpost.php?p=7507937&postcount=81

This one is the ring gate and springs + a superbonus special involving CoP abuse. It's very long.
EDIT: also contains a warp drive. Thinking too hard about space-time and physics.

Eldan
2010-11-29, 08:11 AM
Actually, one of the easiest ways to heat the water is the humble Prestidigitation spell. It can heat things up.

Acanous
2010-11-29, 08:46 AM
well really, the biggest problem would be houseruling the attacks per round, damage, etc.
Unless you wanted to just rip it from the star wars D20 system. But there's some drift between the systems, so :/

Swooper
2010-11-29, 10:09 AM
Those poor, innocent catgirls... :smalleek:

AstralFire
2010-11-29, 10:12 AM
There are no innocent catgirls.

Pelfaid
2010-11-29, 10:52 AM
As someone studying rocket science this thread makes me very happy. My only problem is that this only gives us linear thrust. We need to figure out some way of thrust vector control so that our rocket or missile or spaceship, your choice, can actually be steered. The best I can come up with while studying for finals is the use of vanes in the nozzle. What kind of manufacturing precision does the Fabricate spell have?

As soon as I finish finals up I may have to actually run through all the math.

subject42
2010-11-29, 11:06 AM
As someone studying rocket science this thread makes me very happy. My only problem is that this only gives us linear thrust. We need to figure out some way of thrust vector control so that our rocket or missile or spaceship, your choice, can actually be steered.

Couldn't you just use that one spell in the Spell Compendium that lets you re-orient gravity as a free action every round?

Mando Knight
2010-11-29, 02:11 PM
It's actually about 1:9, according to Wiki - 10.3 inch diameter at the throat, 90.7 inch diameter at the nozzle exit.

The ratio is calculated using areas, not diameters, so it's a 1:78-ish throat:nozzle ratio. Again, my 1:100 estimate was based off of eyeballed measurements, which I'd say is a pretty good estimate without having an actual system of measurement at hand.

Gavinfoxx
2010-11-29, 02:26 PM
As someone studying rocket science this thread makes me very happy. My only problem is that this only gives us linear thrust. We need to figure out some way of thrust vector control so that our rocket or missile or spaceship, your choice, can actually be steered. The best I can come up with while studying for finals is the use of vanes in the nozzle. What kind of manufacturing precision does the Fabricate spell have?

As soon as I finish finals up I may have to actually run through all the math.

Thats easy. Make the flying ship you are making an effigy, and put the thrust thing into the tailtip.

IthilanorStPete
2010-11-29, 02:47 PM
The ratio is calculated using areas, not diameters, so it's a 1:78-ish throat:nozzle ratio. Again, my 1:100 estimate was based off of eyeballed measurements, which I'd say is a pretty good estimate without having an actual system of measurement at hand.

Ah. Sorry, I'm not actually that familiar with the more practical aspects of rocket engineering.

Mando Knight
2010-11-29, 04:49 PM
Well, it helps if you remember that the diameter isn't even directly useful: gases move across areas, not radii, and so it's the area ratio that will more directly tell you the total expansion of the exhaust. At any rate, my point with the original comment was that a proper nozzle isn't exactly small, despite the "small" throat.

Jack_Simth
2010-11-29, 05:59 PM
As someone studying rocket science this thread makes me very happy. My only problem is that this only gives us linear thrust. We need to figure out some way of thrust vector control so that our rocket or missile or spaceship, your choice, can actually be steered. The best I can come up with while studying for finals is the use of vanes in the nozzle. What kind of manufacturing precision does the Fabricate spell have?

As soon as I finish finals up I may have to actually run through all the math.How do gyroscopes sound? Really, you can mount a regular decanter or two on a wheel, set them both to Gyser, and watch them spin, to get yourself a gyroscope of arbitrary size. Okay, you'll need some way of disposing of the water, but meh.

Tvtyrant
2010-11-29, 07:15 PM
Hmmmm, you could steer by moving the thruster actually. Place the barrel/thruster on the end of a long pole, and then move it using telekinesis. The length of the lever will lower the amount of needed pressure and let you alter course. Or have the fighter wrangle it :P

Morph Bark
2010-11-29, 07:22 PM
Sorry, that was all I can remember. It was years ago, they may have deleted it by now. I know every detail of how to make the ship except where the rune was from.

JaronK

Why don't you post the rest of the details you DO remember, JaronK? Someone here might get their memory jumpstarted somehow and remember where the rune is from. :smallwink:

Gavinfoxx
2010-11-29, 07:25 PM
Why don't you post the rest of the details you DO remember, JaronK? Someone here might get their memory jumpstarted somehow and remember where the rune is from. :smallwink:

Also, the names / screennames of anyone else who was in that thread would be great too! I could track them down maybe?

JaronK
2010-11-29, 08:18 PM
As someone studying rocket science this thread makes me very happy. My only problem is that this only gives us linear thrust. We need to figure out some way of thrust vector control so that our rocket or missile or spaceship, your choice, can actually be steered. The best I can come up with while studying for finals is the use of vanes in the nozzle. What kind of manufacturing precision does the Fabricate spell have?

As soon as I finish finals up I may have to actually run through all the math.

Considering our "rockets" are only about a foot long or so and weigh next to nothing, plus require no extra attachments, what's wrong with mounting them in some kind of swivel mechanism? As long as it can handle the thrust, you could steer them almost like a boat.

Why don't you post the rest of the details you DO remember, JaronK? Someone here might get their memory jumpstarted somehow and remember where the rune is from.

I did exactly that a few posts back. Everything I remembered from the thread, except the exact sources on how some of the abilities were made. In case you're wondering, atmospheric controls were done with a Chamber of Comfort, Permanent Reverse Gravity was the artificial gravity solution (or you could use extra dimensional space in the form of portable holes, in which gravity was normal and inertia wasn't an issue), and we used Prismatic Walls from Stronghold Builder's Guide as the primary exterior shielding.

I think that's all I've got.

JaronK

Tvtyrant
2010-11-29, 08:29 PM
.... Actually instead of a real space ship we could just make a rocket with one bag of holding that contains dozens of layered bags of holdings in them. They would all be slightly open and you simply put a Mages Mansion in each one. Win!

Or we simply cast rope trick and stay inside while the rocket moves us around.

Gavinfoxx
2010-11-29, 08:31 PM
I think that's all I've got.

JaronK

No names of other thread participants?

JaronK
2010-11-29, 08:45 PM
No.

JaronK

Tvtyrant
2010-11-29, 08:58 PM
What level would a party have to be to create a reasonably useful spaceship using the method we are discussing here? I'm suggesting we have a level 7 cleric at least to cast Hallow and Resistance from Energy Cold permanently in the ship, so we get dmg reduction 20 against the cold of space.

JaronK
2010-11-29, 09:03 PM
The cold of space is an illusion. Think for a moment about how many thermoses work... by putting a vaccuum between the hot liquid and the surrounding environment, it stays hot. Space is just like that. Space is a VERY poor transmitter of heat... in fact, if you have any significant heat source in a space ship, keeping it cool becomes a bigger issue than keeping things warm. Space itself is very cold, but it doesn't somehow transfer that cold to your ship at all. This is especially true when the outside surface is covered with Prismatic Walls, which stop everything, including cold damage.

This is why a Chamber of Comfort completely handles atmospheric controls... one thing it does is set the inside air temperature to 70 degrees Fahrenheit. Problem solved.

You'd want an Artificer to do most of the building for obvious reasons. The hardest things to make, IIRC, are the Prismatic Walls that will form your primary shielding. Get an Archivist to plan the ship out though... he can cast Divine Insight and use other knowledge boosting abilities to make his Knowledge (Arch and Engineering) check extremely high.

JaronK

randomhero00
2010-11-29, 09:04 PM
OP:

I suppose that might work if your DM is the type to fit in real world physics...but most never try to bother because DnD is just not based on real world physics. Funny/interesting idea though.

flabort
2010-11-30, 12:19 AM
Someone in one of the linked threads mentioned glueing two portable holes back to back. I'm not sure what they intended to do with it, But putting ring gates and a decanter inside, then "rolling" one into the other would certainty do something. I doubt it would do anything good, but yeash.

I've got to go take two advil and go to bed.

Gavinfoxx
2010-11-30, 12:23 AM
OP:

I suppose that might work if your DM is the type to fit in real world physics...but most never try to bother because DnD is just not based on real world physics. Funny/interesting idea though.

I just wanna find the damn source of that damn rune!