How many thrusters do I really need?

[PastaEngineer]

Anyone have any idea how you would decide how many thrusters to have on a spaceship? Clearly you could hobble your way across space with one thruster and enough production to sustain it but that's boring. Then I noticed the thruster performance curve in the Factoriopedia: (blue: fluid usage, green: thrust, orange: efficiency)


It got me excited but then I realized the x-axis here is fuel consumption rate, which I have no idea how to even begin controlling that. The graph seemed to be rather useless in gaining any kind of information I could put to use. Any other calculations I tried to do for how much fuel to stock, thrust for acceleration, etc are just all over the place. I'm no rocket scientist but my math diverges from the game by 6 or more orders of magnitude. Only other thing I could find out (via in-game testing) was that each thruster gave a top speed increase of roughly 10km/s.

Maybe I'm meant to just guess and slap a couple of thrusters down and call it a day but it seems rather bland.

[mmmPI]

I suggest starting with 1

Then you can always add more, it's less risky than the opposite.

Besides you may not want the full power , or have the material to sustain even a single thruster at the beginning of the game depending on how early you start the space exploration.

To me that's when efficency comes into play, the thruster is more efficient when it is at low consumption, it helps failing ship

If you want to seek the efficiency , or if you need it, you can use pumps to throttle the fuel going to the engine, or you can connect the chemplant producing it to circuit, to make sure they do not run at full capacity, that can also be used to prevent giving too much power to the thruster and make the platform go too fast.

[DragoonGXG]

After doing some testing here's what I got.

TL;DR:

One engine will make anything move, just very slowly for large platforms.

The "Science":

Keeping the engines with maxed out fuel inside of them = inefficient.
This would be similar to a car trying to "hyper mile" vs full throttle to get somewhere.
Your goal would be to keep the fuel inside each engine to about 30-40% fuel capacity (Yes, inside each engine. Not from external connections).
If someone can figure out this next problem, then maybe a ratio of weight to thrusters can be established.

Tests.png (22.27 KiB) Viewed 1365 times

Looking at the results, more thrusters eventually start to give diminishing returns.
One thing to note though, the time it took to reach "top speed" was shorter the more engines involved.
With 7 engines, reaching top speed was near instant.

(My) Problem:

I was able to test this by having no fuel in the system prior to launching.
As I collected asteroids and started refueling, the efficiency shot up to +80% while I traveled at a moderately "slow" speed.
What I'm currently not savvy on is HOW to limit the input pipe(s).
Pumps don't seem to be the solution as they are too quick at filling each system.

Any takers on pipe flow limiting?
IF you want to share some Space Age tips and tricks, try checking out viewtopic.php?f=18&t=117167

[mmmPI]

Keeping the engines with maxed out fuel inside of them = inefficient.
This would be similar to a car trying to "hyper mile" vs full throttle to get somewhere.
Your goal would be to keep the fuel inside each engine to about 30-40% fuel capacity (Yes, inside each engine. Not from external connections).

clearly not, you have an infinite research called "asteroid efficency" which soons leads to having massive surplus of ressources that you need to avoid picking up, or throw overboard

And getting your thruster to absolute max speed is useful and even recommended if you carry science packs that spoils overtime.

[DragoonGXG]

clearly not, you have an infinite research called "asteroid efficency" which soons leads to having massive surplus of ressources that you need to avoid picking up, or throw overboard

And getting your thruster to absolute max speed is useful and even recommended if you carry science packs that spoils overtime.

I'm talking about the chart mentioned inside the OPs comment / found in the Factoriopedia.

[mmmPI]

I'm talking about the chart mentioned inside the OPs comment / found in the Factoriopedia.

Yes and you conclude that the goal should be to try and keep between 30 and 40% fuel inside a thruster. Which is why i said clearly not. When you want your science pack to not spoil you put much more fuel than 30 or 40% to have more thrust. And if you wanted more efficency you'd put less than 30 or 40%. The goal should not be a target efficency imo that serve little purpose in game, what i think you target is a speed , or time for a certain trip. This regarding the question how many thruster do i need.

If someone can figure out this next problem, then maybe a ratio of weight to thrusters can be established.

The formula for speed involve the width of the platform too.

[DragoonGXG]

The formula for speed involve the width of the platform too.

Oof, looks to be some fun math coming up.

[mmmPI]

Oof, looks to be some fun math coming up.

If you think it's fun :

space_platform_acceleration_expression = "(thrust / (1 + weight / 10000000) - ((1500 * speed * speed + 1500 * abs(speed)) * (width * 0.5) + 10000) * sign(speed)) / weight / 60"

I think it's even worse than the curves from the factoriopedia in helping to choose how many thrusters x)

[MBas]

Hello guys.

You can check my system to control fuel input into thrusters. It is very accurate ("very" is indeed relative but I am quite satisfied).
viewtopic.php?f=193&t=118009

There is a possible improvement that fuel input is not set manually but delivered from the ship parameters. For example you can make fuel consumption dependent on fuel in tanks so it automatically adapt efficient regime according to your fuel production. Or put it higher when you carrying bio science etc.