Thruster vs chem plants ratios

[Avezo]

Sorry if it was alredy asked somewhere, but I'm getting lost with calculating how much fuel and oxidizer do I need to produce during the transit between planets.

Lets say I have 3 thrusters, each consume 120/s each. 360/s total.
1 chem plant produces 37.5/s each.

So, it seems I need almost 10 chem plants for each fluid to sustain thrust during the flight, still, I'm not really seeing anyone having that many on early small platforms - so what am I missing here?

[Tertius]

You don't operate the thrusters with full fuel. The more throughput they have, the more inefficient they work. You get more speed if you feed double the thrusters with half the throughput.

Also see here for background and how to limit throughput: viewtopic.php?p=626728#p626728

If you're starting to explore the first planets, it's sufficient to use 1 plant for each fluid feeding 3 thrusters. It's more efficient than 1 thruster, although you not even fully fuel a single thruster with just 1 plant.

[WOOL]

There are a couple of options here. The thruster can use less fuel than 120/s, and is actually more efficient when doing so. There is a table on the wiki with some numbers

https://wiki.factorio.com/Thruster

You can also limit the fuel throughput using the circuit network, although not directly, there are some ideas in this thread

viewtopic.php?f=193&t=118009

Also you can use storage tanks and only allow the platform to move when there is sufficient fuel / oxidiser available

Final point, if you leave it as it is the thruster will just consume the output of the chem plants and find a balance point

[jaylawl]

additional point: once you unlock the advanced recipes for fuel crafting, it will become very easy to run your thrusters at 100 % should you wish to do so. but you will need to deal with limiting fuel input eventually once you start traveling to Aquilo or further, due to high speed becoming quite hazardous out there.

It is extremely easy to limit the fuel intake of the thrusters using a pump each for fuel and oxidizer, a decider combinator and a single constant combinator.

A regular quality pump has a throughput of 1200/s (or 1200 per 60 ticks).

Let's assume you want to feed your thrusters 300/s (or 300 per 15 ticks).
Set up your constant combinator to output a constant "T" with a value of 1 and hook it into the input of your decider combinator.
Set up the decider combinator like so:

ticks.png (11.67 KiB) Viewed 1507 times

This way it will count to 60 and then reset, giving you a clock.

Then hook the output to your pumps and set the pumps to only activate when the signal "T" is < 15. This way the pumps will only feed 300/s to your thrusters.

This is as simple as a fuel intake control as you can make and it works splendid.

And as long as you dont set the intake to be higher than your production rate you are guaranteed constant acceleration.

[Avezo]

Thanks a lot everyone!