[Axel]

Why would we do that? Their volume already makes the charge more expensive.
We need to determine X by deciding how much we want a full trip to cost and then work backwards.. Now, assuming the ship has 50 charges that means that the total cost of the ship's FTL jumps would be:
Cost = 50 * X * V
Now, we can estimate the dimensions of the Tarrasque. All we need to know is what we think fully charging the Core should cost.

[Lyinginbedmon]

Given the equipment needed to create the thing in the first place, I'd say 1-2 million GP (Possibly PP) would be the least, since space travel is an expensive business

[Axel]

2 million GP, for one trip? What's the ship gonna cost, then?

[Lyinginbedmon]

I don't even want to know, but I'd assume it'd be in the 10 millions at least, I was just thinking in terms of magnitude that the teleport itself would probably cost less than the entire ship, hence the ability for it to be paid for multiple times, but it should still be very expensive

[Dthclaw]

Probably in the neighborhood of 10-15 M gp. Which, given that simple orbital space programs are a significant amount of US budget, reasonably, then, developing and constructing an interstellar craft should be a larger proportion of a nation's economy. More has to go into this than just the craft - you need the research facilities, the construction facilities, mining and crafting, transportation of raw materials and components, labor costs (optional, depending on who's building it), launch/landing facilities (if any), control and admin facilities... this whole project should, in all, be upwards of 50-60 million gp when all is said and done. A given craft might only be 10-15 million for components, but like a golem lab, you can reuse the facilities (assuming the nation's economy hasn't collapsed).

Perhaps, if this nation sees further benefits from the Tarrasque, they can start researching ways to lower the charge cost (2 mil seems a reasonable entry-level cost, btw). X could be some measure of how much development they've done, and how advanced the magitech core is. The more work done, the smaller X becomes. Or heck, maybe they can find or salvage equipment for the ship while they're exploring. If space travel is fairly common in your campaign, finding refit facilities wouldn't be too hard. Improved magitech cores would be one possibility (remnant from fey-giant conflict, perhaps).

[Axel]

If we're using the world of our local golem expert I have a feeling that finding a golem lab and artificer capable of this project won't be hard.

Hey, that's good. Give each Core a different X value to reflect how advanced it is. Ok, so assuming a total 2mil cost to charge the Tarrasque for one trip and a volume of... what the hell are the dimensions of the Tarrasque, anyway?

[Lyinginbedmon]

The Tarrasque (creature) is 70 feet long, 50 feet high, and 30 feet wide

[Raven Bloodmoon]

V = 439,823 cubic feet.
C = 2,000,000 gp

C = X * V
C/X = V
1/X = V/C
X = C/V

(Everyone follow that?)

X = 4.547284 GP / cubic foot

This assumes 1 charge costs 2,000,00 GP, but I think you meant all 50 cost 2,000,000

SO

X = C/(V * 50)

X = 2,000,000 / (439,823 * 50)
X = 2,000,000 / 21,991,148
X = 0.09

Now you have a gp cost per 50 charges. So let us now find out what the cost per charge is:

As 50 charges cost 2,000,000 GP, one charge will cost 1/40 of that cost. Thus, one charge costs 40,000 GP. Dividing this amount by 25 will yield the XP requirement per charge: 40,000 / 25 = 1,600 XP.

Thus we see that a single charge will cost 40,000 GP + 1,600 XP. I think this is sufficiently expensive to make space travel quite restrictive while still in its infancy. All of these figures will become cheaper as time goes on, but we now know how much this thing will cost to charge.

Next up: How much to build? I think we shoudl get fanciful here and decide juse what makes it tick. I am going to rip off the Indian vimanas of the Rg Veda and Puranas and say that it is powered by an inverted cone of liquid mercury that is heated. It is by this crucial core that the power to fly is maintained.

[Lyinginbedmon]

I'd say a nuclear reactor or a (obviously ripped-off) warp core, but I suppose if they can figure out nuclear power then the whole world is doomed before it can start the production phase. Perhaps it's an amplified, permanent, chain lightning inside of a containment area that powers it? It could then use simple engines to keep itself aloft (I say simple engines, I mean simple for us)

[WoeTheSinner]

Oh my! I love combining two fantasy genras!

Raven, can you do me a favor please? Since is your baby, can you please summarize what has been agreed upon by you and the posters and what the outstanding issues are and edit the 1st post to reflect this. That way we can have a quick 'to do' list type of thing and also I can have a guide to go by when deciding whose ideas made it through.

Go Tarasque GO! Ispirational art to follow...2E style...

[Dthclaw]

Heh. That could be the symbol slapped on its hull.

[Dthclaw]

I know Axel's gonna hate this one, but I'll throw it out anyway. Power it with two portals to the positive and negative energy planes aimed at each other. Kinda like a fantasy matter/antimatter reactor.

[Lyinginbedmon]

You're right, he will hate you, and I'm none too pleased either. Opening a portal to the Positive Energy Plane and the Negative Energy Plane is total suicide!

[Ssri-Tel-Quessir Hitokiri]

Umm... guys... Look at the fly speeds of something like the carpet of flying. Because you are using magic to power the flight, it doesn't matter how big the object is or how heavy it is. It will still move at a constant speed...

[WoeTheSinner]

I'm going to agree with Ssri, we are using Magic...MAGIC fly speeds should not be an issue vs size, though they should still be thought out for balance.