GURPS Spaceships Design Spreadsheet

[ericbsmith]

Originally Posted by Mgellis

Eric, sorry, but another weird error has popped up. On small ships, the Hnd/SR cell gives me a #Value! error. It only happens on ships of SM+6 or smaller.

Hey, no need to be apologetic, you're doing exactly what I'd like you to do; you're finding bugs and reporting them back to me. Thanks!



Posted Version 1.19h
Fixed the Hnd/SR bug for ships below SM+7
-Added Fuel Tanks which specify the type of fuel they contain.
-Engines will now base their Delta-V on how many fuel tanks have the appropriate type of fuel in them.
-An unspecified Fuel Tank will count towards the Delta-V of any fuel using Engines.
-Conversion Drives use the total of all Fuel Tanks to calculate Delta-V, since they can use any fuel.
-Accel & Delta-V displayed in the table entry still work as before; Accel is equal to total Accel of all engines, Delta-V is the single highest Delta-V among all engines. (I plan on fixing this at a later stage)

[Mgellis]

Hmmm...I can't get some of the fuel types like Ammonia and Water to work properly. Or is this part of the spreadsheet still in the "beta" stage?

You can add the tanks, but it does not affect acceleration and the delta vee is not shown. In fact, it does not show any delta vee, only the engine type's base acceleration.

I am assuming that any thermal rocket (nuclear, antimatter, etc.) should be able to use water, ammonia, methane, or hydrogen. Laser rockets, too, since they just heat up reaction mass--in theory, you could use anything as reaction mass for a laser rocket. Dean Ing suggested ice, I think, in Future of Flight. Or am I mistaken about this?

Oh, just to make things complicated...I understand that nitrogen has been suggested as reaction mass fuel for thermal rockets, etc. It sort of makes sense; it's available in large quantities, easy to liquefy, and doesn't explode the way methane or hydrogen can. Should it be added as another optional fuel?

Mark

[ericbsmith]

Originally Posted by Mgellis

Hmmm...I can't get some of the fuel types like Ammonia and Water to work properly. Or is this part of the spreadsheet still in the "beta" stage?

I consider most of the sheet to be in beta at this stage. As I work on things I've been finding lots of minor errors I've been correcting along the way, and every time I add in some bit of functionality I wind up having to rewrite a ton of stuff that I wrote in the past, so there's lots of potential for breakage.

That said, in the last beta I believe that I'd added the drop-down menus for the alternate fuel types but had yet to hook in the functionality. I just uploaded my current version, which should have the fuel stuff complete. It now generates notes for each engine stating what type of fuel it is using (handy both for when using an alternate fuel and to figure out what type of fuel a given engine actually uses). It also calculates a Delta-V figure for each type of engine and displays it under the entry field for that engine, and displays the single best Delta-V on the the Vehicles Table.

Originally Posted by Mgellis

You can add the tanks, but it does not affect acceleration and the delta vee is not shown. In fact, it does not show any delta vee, only the engine type's base acceleration.

The tanks themselves don't affect Acceleration or Delta-V, they only add fuel mass for calculating Delta-V later. The Acceleration and Delta-V is changed when you specify what type of fuel is used by the engine in the drop-down menus all the way to the right, next to the cost break-down. You can specify a different fuel for each individual engine. So now you can have two of the same rocket, one with Hydrogen Fuel for the Delta-V and one with Water for the thrust. Or course, then you need two fuel tanks and the rockets can't use each others fuel.

Originally Posted by Mgellis

I am assuming that any thermal rocket (nuclear, antimatter, etc.) should be able to use water, ammonia, methane, or hydrogen. Laser rockets, too, since they just heat up reaction mass--in theory, you could use anything as reaction mass for a laser rocket. Dean Ing suggested ice, I think, in Future of Flight. Or am I mistaken about this?

Oh, just to make things complicated...I understand that nitrogen has been suggested as reaction mass fuel for thermal rockets, etc. It sort of makes sense; it's available in large quantities, easy to liquefy, and doesn't explode the way methane or hydrogen can. Should it be added as another optional fuel?

I might consider adding some optional fuel types to the sheet, to go along with my other optional rules, but right now I'm sticking to the stuff that's in the books. Water is in SS1, and SS7 introduces Ammonia and Methane.

[Mgellis]

Originally Posted by ericbsmith

That said, in the last beta I believe that I'd added the drop-down menus for the alternate fuel types but had yet to hook in the functionality. I just uploaded my current version, which should have the fuel stuff complete. It now generates notes for each engine stating what type of fuel it is using (handy both for when using an alternate fuel and to figure out what type of fuel a given engine actually uses). It also calculates a Delta-V figure for each type of engine and displays it under the entry field for that engine, and displays the single best Delta-V on the the Vehicles Table.

It is showing the fuel--that is a nice feature--and the high thrust switch is working, but I still cannot get it to accept alternate fuels. For example, the antimatter thermal engine uses hydrogen and with the generic fuel or hydrogen it works fine. If I switch over to water, it behaves as if I had not added a fuel tank at all. Or am I just doing it wrong?

Thanks again for all your work on this. What a cool program!

Mark

[ericbsmith]

Originally Posted by Mgellis

It is showing the fuel--that is a nice feature--and the high thrust switch is working, but I still cannot get it to accept alternate fuels. For example, the antimatter thermal engine uses hydrogen and with the generic fuel or hydrogen it works fine. If I switch over to water, it behaves as if I had not added a fuel tank at all. Or am I just doing it wrong?

You're doing it wrong. All the way to the right of the High-Thrust & Ram-Rockets checkboxes there's another column where you can specify the fuel that is used by the Rocket. If you switch that to one of the alternates then the accel & delfta-v of the engines will be recalculated to the new fuel and it will use fuel tanks filled with that kind of fuel.

[Mgellis]

Originally Posted by ericbsmith

You're doing it wrong. All the way to the right of the High-Thrust & Ram-Rockets checkboxes there's another column where you can specify the fuel that is used by the Rocket. If you switch that to one of the alternates then the accel & delfta-v of the engines will be recalculated to the new fuel and it will use fuel tanks filled with that kind of fuel.

I found it...and promptly designed a SSTO shuttle using antimatter engines (high thrust and water as fuel...drinks fuel like mad, but you can get eight passengers and 2.5 tons of cargo to orbit--or the moon, I suppose, as the total delta vee is 8.4 mps). Yes, now that I know where the switch is, it works beautifully. Thanks!

[Dark_Daemon]

A couple of questions:
Where can I download the latest, beta release? The first post says 1.19a, and your website doesn't say anything about versions.
Related, could you start including version number on the front page and in the file name of the sheet? I've got three different versions bouncing around at this point, and I'm having trouble keeping track.

Thanks for all your work!

[ericbsmith]

The latest beta release, version 1.19i is available at:

http://gurpsland.no-ip.org/zip/Spaceships119.zip

http://gurpsland.no-ip.org/zip/Spaceships119.7z



The last non-beta, version 1.18, is available at:

http://gurpsland.no-ip.org/zip/Spaceships.zip

http://gurpsland.no-ip.org/zip/Spaceships.7z


My website hasn't been updated with any of this; I've just been posting to this thread with information. The website only has a link to v1.18.

[vicky_molokh]

Nice thing. Seems to mostly work even in OpenOffice, at least at first glance. Is the Divergent and Paranormal support planned?

[ericbsmith]

Originally Posted by vicky_molokh

Nice thing. Seems to mostly work even in OpenOffice, at least at first glance.

Mostly, yes. I see a few spots of incompatibility, which I plan on addressing once I get most of the additions I've added working in Office. The only thing I probably won't port over anytime soon is the Macros.

Originally Posted by vicky_molokh

Is the Divergent and Paranormal support planned?

What Divergent and Paranormal support is missing? In the v1.19 beta's I've added all the systems from SS7, including the Divergent and Paranormal ones. I had an idea of how to improve the Divergent TL handling (right now it's simply treated as just TL7, which I don't like).