Help with calculating jump system

[Panpiper]

I am having a hard time grasping the concept of jump systems and how much I need on my ship in order to get good results. I do know that having 5% of the blocks of your ship in jump modules results in a very fast to charge jump system that takes you a long way, in a small ship. The key word there is small. Getting a permaclock/permajam ship (by definition low mass) to be able to rapidly jump long distances is rather easy. By contrast...

I have found large ships to be utter slugboats, not just with their regular thrusters, but also with jump systems. I just tried putting 25,000 jump modules on a ship of 250K blocks, so 10% of it's blocks, and the difference in jump charge speed compared to having only a single jump module was so trivial, that I was not even sure I could discern it. (I should note that the ship in question also had ~300K blocks of docked entities, turrets and power generators. Still, the 25K jump modules I put it would still have brought the combined total close to 5%.)

Am I missing something here? Are jump systems so hampered by ship size as to be virtually not worth the effort (other than a single block)? Sacrificing 5-10% of a ship's bock total which could otherwise go to shields or what not, is absolutely not worth it solely to gain a truly minute difference in recharge speed. What is it that I am failing to understand?

 

[Heillos]

In order to address your example in the second paragraph, I'd like to know the mass values of your ship + all docked entities (which is displayed in the build mode stat display), as this is the value which is used to determine the requirements of a jump drive. At a guess, though, the difference between 1 module and 25,000 should have been about 20 seconds.

On large ships, making rapidly-chargeable jump drives becomes more and more challenging, primarily because of the energy/sec requirement to charge a drive, which is linearly scaling, and will quickly surpass the power softcap. Also, although I haven't graphed or otherwise properly analyzed it, the percentage of a ship which must be devoted to jump drive modules in order to achieve X charge time will increase as ship mass increases. This leads to a lot of warships being equipped with either 1-block or remarkably small jump drives, and relying primarily on warpgates or wormholes for long-range transport. Making large and fast jumpers requires specialization that most ships cannot afford to have.

Other noteworthy things; the 5% mark isn't even necessarily an "ideal" jump drive, it's just the point at which the equations for total charge required (the total amount of power you have to put in to charge a drive) swap from being quite inefficient to a slow linear increase. The rate at which jump drives consume power in order to charge is linearly determined by the number of jump drive modules.

I've done a fair amount of work with the math involved, and the tools which I have developed are listed here:
https://starmadepedia.net/wiki/Jump_Drive_Computer#Calculators
Perhaps some of these might be of use in your quest for understanding of jump drives.

 

[Panpiper]

The ship's turrets mass almost exactly 30K mass (that's 300K blocks that work out to almost 30K mass). It has four docked reactors totaling 3700 mass and the ship itself currently sits at 31,885 mass, for a combined total of 65585 mass. However the ship's interior is still being filled and when done, I expect it will have an extra 20K mass beyond that.

It has four docked reactors that give it somewhere between three and three and a half million power regen per second. It can very likely handle jump recharge requirements. That of course does not include the seven million power generation in it's turrets.

 

[Heillos]

Alright, thanks for informing me of the total mass. Having run those numbers (using this spreadsheet, should you wish to verify), I must say that I'm not sure how there was no perceivable difference between 1 module and 25,000; 1 module would, as is usual, produce a charge time of ~46 seconds, while 25,000 should charge in about 30 seconds, on a ship of that mass.

You are correct in that your ship can handle the drain; for a 25,000 block drive it is 1.26mil e/sec to charge (this is only affected by the number of jump drive modules). That is, however, already past the power softcap, and for a jump drive that only charges in 30 seconds.

If there's anything else you'd like addressed, please ask; I think I've covered everything though. This has given me some ideas for a few relationships about jump drives which I shall try to graph, and those will be added to the wiki page if I complete them.

 

[Panpiper]

You are a scholar and a gentleman Sir.

When I ran my very informal test, I was eyeballing the results very subjectively, not with a stop watch. I found the time to charge with one jump module to be 'very long'. I found the time to charge with 25K modules to also be 'very long'. Being told now that one was 46 seconds and the other only 30, is very believable. They both remain 'very long'. ;-)

I think what I will probably do is to experiment with the idea of a 'jump tender', to which the warship proper docks. Command then transfers to the jump ship which is capable of both high power generation and huge jump engines. That tender carries the warship to it's desired destination whereupon the warship undocks. This may not be practical (or even legal on some servers), but perhaps worthy of experimentation. Obviously the jump tender itself will have to have docked power reactors of it's own.

On the warship proper, I expect what I will do is to have a bank of jump drives. Now that we can have more than one hotbar, I shall fill an entire hotbar with charged, single module, jump drives. That way I will be able to get a fair distance in 'very' little time, and then recharge them all at my leisure while listening to a YouTube video or something.

 

[Keptick]

You don't necessarily need power regen to be over the jump drive's charging cost. Having a large enough power buffer (capacitors) also works pretty well.

 

[Heillos]

That is correct, although any ship with large capacity, but not enough regen, will eventually have to have some downtime to recharge. How long that downtime will be and when it occurs may vary, but it will eventually happen.

Depending on how far the ship must travel, though, running on capacity rather than regen could certainly work.