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Old 12-06-2006, 12:47 PM   #1
Ieldra
 
Join Date: Jul 2005
Default More GVB questions

...perhaps someone can help me with this:

(1) Armor has no volume? That can't be right.... or if it is right, then why?

(2) My vehicle has a Payload stat. Where does it come from, and how can I influence it?

(3) When I set performance profiles, there's a "payload" parameter. When I increase it, my vehicle gets faster. That can't be right.... or perhaps this parameter is used for something else. Can anyone explain?

(4) How do I convert power to energy? It seems my laser can't use the power generated by the fusion reactor directly? Why not? In one of the example ships, I've seen this.

Last edited by Ieldra; 12-06-2006 at 01:21 PM.
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Old 12-07-2006, 03:32 PM   #2
tjoneslo
 
Join Date: Aug 2004
Location: Vermont
Default Re: More GVB questions

I, the Vehicle Guru will answer your questions:

1) Correct, Vehicle (and GVB) assume armor has no volume, as an abstraction to ease construction. Vehicle Expansions 2 (and GVB) has an option to make armor take volume if you really can't stand the abstraction.

2) Payload weight includes things like weight of crew and passengers, ammunition, fuel, and cargo.

3) The basic performance formulas use vehicle total weight. Some people wanted the option of removing some of the payload (like half of the fuel, or the all of the ammunition). By increasing the "payload" parameter of the performance profile, you are decreasing the total weight of the vehicle, thus improving performance. The idea is you can link the payload item (like the ammunition or fuel) directly to the performance profile so it updates properly.

4) You should be able to create the links. If you can explan more about what you are trying to do, I can write you an example of how to do it.
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Old 12-11-2006, 01:51 AM   #3
Ieldra
 
Join Date: Jul 2005
Default Re: More GVB questions

Quote:
Originally Posted by tjoneslo
You should be able to create the links. If you can explan more about what you are trying to do, I can write you an example of how to do it.
Well, it's easy...or it should be. I want to put a laser into my vehicle that draws its energy directly from the power plant, not from energy banks. I could always use one of the custom weapon types, but they're not as easily configurable as the ones in the regular weapon repository. What it comes down to, I'd like the weapon to be like, for instance, the "TL8 laser", where I can set range, power, shots etc.., and have GVB calculate the rest for me, with the only difference that it draws on the vehicle's power plant directly.

And BTW, thanks for the other answers.
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Old 12-11-2006, 11:47 AM   #4
tjoneslo
 
Join Date: Aug 2004
Location: Vermont
Default Re: More GVB questions

I'm still not clear on what you mean by "link". The term has a specifc meaning within GVB and can cause confusion on my part. So I'll make some assumptions about it, give an explination, and you can point out where I've gone wrong.

I'll assume your vehicle has a fusion power plant and a laser componet added from the repositories, and they are in the same package or component (like the body).

There are two way to link these component together. First is: I want the laser to always use 10% of the power of the fusion plant. The second is: The fusion plant is dedicated to powering the laser, so whatever output I need for the laser, make the fusion plant the proper size.

First way: Right click the package and select "New link node..." from the context menu. In the Edit component links dialog, select (in the select lists from left to right), laser component, rating property, enter 0.1 in the text box, then the fusion plant component and the Total Power Out property. Press OK. Now as you increase or decrease the power of the fusion plant, so does the laser power. You will need to set the remaining items for the laser to get the type you want. You will also need to pay attention to the Kj (output) and the kWs (or kj input) ratio and adjust your multipler in the link above.

Second way: Create the new link as above, and in the edit component dialog select fusion power plant component, rating property, enter 1 in the text box, then select laser component and Total energy In property.

If it's not apparent from the description above, the beam weapons still use the qantity and rating items that the other templates use, they are just not labled on the edit dialog. Quantity is quantity and ratiing is the Kj input.

Does that answer your question or have I missed it entirely?
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Old 12-12-2006, 04:23 AM   #5
Ieldra
 
Join Date: Jul 2005
Default Re: More GVB questions

I never mentioned the term "link" - not in any of my posts. Apart from that, I didn't want to make a quantitative link from the power source to the power-using item.

To make it all very clear: I have a small spaceship with two turrets. I want to add a "TL8 laser" from the beam weapons repository to every turret, and I'd like the lasers to be powered by the ship's main power plant.
The problem: after I add the lasers, "Energy in" shows up in their display, but they don't draw on any power *at all*.

As an example, if my power plant has 10 MW and my lasers have an energy output of 200KJ each and an RoF of 2, making for a total power requirement of 800 KJ/s = 800 KW, the power plant should be able to supply the power for the lasers. But that isn't what happens. Instead, I get a energy need I haven't supplied and a power output I don't need.

Further analyzing this problem, I see that the calculation above makes the assumption that a laser shot from a laser with RoF 2 takes 0.5 seconds, which is, IIRC, the correct interpretation of what I read in GURPS Vehicles, that a laser shot is a continuous beam unless stated otherwise.

To avoid using assumptions like this, for instance, in order to create a pulse laser, I could use energy banks, which I understand is the default way to power lasers in GURPS Vehicles. But apart from the fact that I don't always want to do this, the result is an incorrect power balance, since the energy banks must be recharged, and they don't have a power-in parameter.

All this means that, whatever I do, the power balance is wrong, and maybe the energy balance, too. For this small spaceship, it's not a big problem. I can do the calculations myself and be done with it. But with Star Wars-Type spaceships I'd need an extra spreadsheet for the power and energy calculations, and I always assumed GVB existed to take care of these things for me...

EDIT:
Maybe the best way to handle this is to duplicate the power cell template and edit the new template to be rechargeable in one second (Power In = Energy Out / 1 s). After I have added the power cells to power the lasers, I'll have a meaningful power balance again. This is an around-the-corner simulation of a weapon powered by the power plant, but it does the job, and maybe it's even technically somewhat realistic.

EDIT2:
Ticking the "rechargeable" checkbox should add a power need to power cells and suchlike, as a fraction of the energy output, to show the maximum recharge rate, maybe TL-dependent. This should also be editable up to the energy output.

Last edited by Ieldra; 12-12-2006 at 04:54 AM.
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Old 12-12-2006, 12:13 PM   #6
tjoneslo
 
Join Date: Aug 2004
Location: Vermont
Default Re: More GVB questions

Ah, the light dawns, the problem being (for example) the Total Power Use + Total Energy Used should match the Total Power produced + Total Energy Produced on the Edit Body (or other subassembly) dialog.

Unfortuantely, from the persective of GVB, power and energy are two completely different things in the way that cost and weight are different.

The only way to do this is to build a power converter component, in the manner you suggested, by copying the powercell component and making sure there is both a power in and energy out.

There is no requirement in GVB that the energy and power requirements match, which is probably why no one else has complained of this.

If you ever get the "power converter" component working properly, post a copy of the component output here on the forumn so I can add it to the GVB base repository.
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Old 12-13-2006, 02:40 AM   #7
Ieldra
 
Join Date: Jul 2005
Default Re: More GVB questions

Quote:
Originally Posted by tjoneslo
If you ever get the "power converter" component working properly, post a copy of the component output here on the forum so I can add it to the GVB base repository.
Actually, the basic version is so easy I won't bother with any output, since I don't know which output you mean: just duplicate, for instance, the "TL8 power cell", and call up the edit template window. Rename it "TL8 power converter cell" and copy the energy-out formula to the power-in formula. You're done. Don't forget to save the repository...

Usage:
Use of this item assumes that the power converter cell collects all the energy in can contain in one second of power input from the power plant. I'm still working on the other versions - these will be needed because power requirements become prohibitive for big lasers like space combat lasers if all the energy needs to be generated within one second.

(I-1) The very basic version
If you have a weapon in a turret or other weapons-carrying subassembly, put the power converter cell into the turret along with the weapon and edit the KWs and Cells parameters until the energy output matches the energy needed by the laser. In the subassembly overview, you now have a balanced energy budget and a power requirement - which is as it should be.

(I-2) The less basic version
Do as described above, but instead of entering the KWs and Cells parameters manually, leave their default numbers and instead create a link node between the laser's energy input and the converter's energy output. (power converter->rating = 1xlaser->TotalEnergyIn). Now, if you do anything that changes the laser's energy requirements, the power requirement for the turret will change accordingly.

Last edited by Ieldra; 12-13-2006 at 02:46 AM.
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Old 12-13-2006, 04:29 AM   #8
Ieldra
 
Join Date: Jul 2005
Default Power converters II

Now for the more complicated versions:

The standard assumption for beam weapons and jump drives in GURPS Vehicles is that they are powered by energy banks recharged either not at all or by slow power input from the power plant. The latter is not modelled by the items in the GVB repository so far, which is why I'm doing this. This delayed-recharge version of a weapon's power setup means that

(1) the energy banks must be able to store more than one second of a laser's energy requirement. They should be able to store enough that the lasers get through a heavy fight without becoming useless.
(2) the power requirement for the recharging of the energy banks may be much lower than in the example in the previous post, since the power plant doesn't necessarily need to supply all the energy within one second.

Here's an example:
Suppose we have a laser with a total energy requirement of 100MJ in a turret (it doesn't matter how GVB arrives at this total, just use the number). Taking the heaviest fights we can reasonably expect into account, let's say the power converter complex must be able to store 100 seconds of continuous firing (10GJ). The need for this long should be extremely rare in most settings unless it's something like Star Wars. Let's also say that it must be able to be completely recharged within 10 times the time it takes for the laser to deplete it (1000s). Power requirement for this setup would be 10MW instead of 100MW for the continuously powered version, but the capacity of the energy storage needs to be 100 times higher.

Here's how to do it:

Editing the template:
Duplicate the "power converter cell" from the example in the previous post. Rename it to something descriptive like "power converter complex" (an item like this can be described as a transformer/energy bank complex). Activate the vUNITS Parameter by typing "Recharge time (s)" into the "Units Name" field. Change the power-in formula to "vQuantity * vRATING / vUNITS".

Usage:
As in the example in the previous post, add the new item to the turret with the laser. Enter "1000" into the Recharge Time field (we want the energy bank to be recharged in 1000s). Create a link node, and link "power converter complex->rating = 100x laser->TotalEnergyIn" (we want the energy bank to be able to store 100 seconds of continuous laser fire).

Notes:
(1) Please note that you don't get a balanced energy budget with the delayed-recharge version, not for the subassembly and not for whole vehicle. But that's not important: if the components and links are set up correctly, and this kind of setup is used for all components that use energy instead of continuous power, such as jump drives and beam weapons, the power usage for the whole ship will be tracked correctly through all components. In the end, just make sure that your power plant matches the power requirement. Everything else will be done by the links and GVB itself.
(2) Each kind of energy-storing item that can be recharged needs its own "power converter" version.
(3) You can use the delayed-recharge version for the simple power converter setup in the previous post, too: Just set both the recharge time and the multiplier in the link node to 1. This way you'll need only one additional item per power storage technology in the repository.
(4) If you use standard GURPS Vehicles rules, it will be necessary to use the delayed-recharge version for space combat lasers, because otherwise, for most spaceships, your power plant will take up too much space and weight, and 90% or even more of it will be used to power the weapons. This would be very inefficient since the lasers aren't used 99% of the time.
(5) The size of the energy banks in the delayed-recharge version is a tactical consideration, especially if the achievable size is limited by technology or economics.
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Old 12-13-2006, 09:08 PM   #9
tjoneslo
 
Join Date: Aug 2004
Location: Vermont
Default Re: More GVB questions

Thank you for this. I will note in the new version of Vehicle Builer (book) and GVB, this problem goes away because everything is done in "power", and no more energy.
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Old 12-14-2006, 08:52 AM   #10
Ieldra
 
Join Date: Jul 2005
Default Re: More GVB questions

Quote:
Originally Posted by tjoneslo
Thank you for this. I will note in the new version of Vehicle Builer (book) and GVB, this problem goes away because everything is done in "power", and no more energy.
Hmm, I'm not sure I like this. It's simpler, but makes more assumptions. I'd rather keep the more complex system and create some "shortcuts" for those who don't like all the detail.
Ah well, let's see how the book turns out... Any idea when we'll see it?
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