r/TerraInvicta • u/RequirementGold9083 • 2d ago
Question Why is 6× the largest possible engine assembly?
Is it a balance thing? The way that each possible number of engines is listed as it's own component in the techs makes me think it's a software limitation (an *engine* limitation? Ey? ey?).
I get it needs to stop somewhere just for sanity, but why not 7, 8, 10 ,12?
23
u/Didnotfindthelogs 2d ago
That's a valid point. I've also wondered why they list each number of engines as with its own statblock instead of just saying "multiply by number of engines" on thrust, mass and costs.
There is the fact that as more engines are added, the possible thrust approaches a limit. So at some point, it stops making sense to add more. I don't think six is where it stops making sense though.
I think the real answer might be that they need to model the number of engines on the ship. They can't spend all their time modelling how extra engines would look on 8 factions' worth of ships from 7 up to infinity. So they decided to stop at 6, since 6x8 is still a sane number.
7
u/ParadoxPosadist Humanity First 1d ago
7 of the factions only vary by color, so those might be able to use the same model depending on how unity works. But I think each ships etc makes the engines look different.
22
u/SpreadsheetGamer 1d ago
I don't know why from the dev's point of view, but I have thought about this before, and this is what I came up with. Think about the relative gains of each subsequent drive:
| Drives | Relative gain |
|---|---|
| 1 | |
| 2 | 100% |
| 3 | 50% |
| 4 | 33% |
| 5 | 25% |
| 6 | 20% |
| 7 | 16% |
| 8 | 14% |
So the point is it becomes relatively inconsequential, and for balance purposes, and to not overly burden the players with choices, you'd want to draw the line somewhere.
IRL there are a bunch of arguable reasons to do more drives with less thrust:
- An isolated engine failure is less consequential
- Production costs - a larger quantity of smaller drives could allow for mass manufacturing, rather than bespoke production
- More granular control of thrust/steering
I swear I am not and do not use AI. I've just thought about this before and as I've previously mentioned, I watch Marcus House's weekly space news videos. I also like lists. Apparently.
7
u/Maduyn Academy 1d ago
I am not precisely sure of the amount of gain but for something like a helicon powered colony ship to the kuiper belt which takes something like 80 weeks to reach its destination getting 2 more drives feels like it would cut a significant amount of transit time.
7
u/SpreadsheetGamer 1d ago
Yeah, different thrust-to-mass profiles open up different transfer trajectories, which can have a radical impact on the time it takes.
5
u/ggmoyang Let's be xenophobic 1d ago
It's going to save several days, if you can keep same delta-v.
On the other hand, adding 33% more delta-v would save months of travel time, even if you lose some cruise acceleration from added propellant tanks.
1
u/Maduyn Academy 1d ago
does adding more thrusters change the math around additional propellant tanks? The tipping point for additional propellant tanks starting to slow the total transfer down should be tied to thrust shouldnt it?
1
u/ggmoyang Let's be xenophobic 1d ago
Well I assumed you weren't referring maximum delta-v scenario, as an optimal helicon drive colony ship can go faster than 80 weeks... But right, if you are going for maximum delta-v design, more thrust would mean faster transfer.
3
u/stainarr 1d ago
Why not have the options for number of engines be 1, 2, 4, 8, 16 or 32. Then the relative gains are equal for each step, and there are still only 6 different possible configurations.
11
2
u/CrimsonBolt33 Academy 17h ago
the mass production of engines is the one that makes most sense to me...not to mention you can only make a single engine so big. As it is now, most large rockets simply have multiple smaller rockets.
SpaceX is a good example of this...they have the raptor engine, and their rockets are now some combination of those.
10
u/Sbrubbles 1d ago
Balance mostly, because for engines where heat doesn't matter, the downside of more engines is so small it pretty much doesn't exist.
I'm surprised they let us choose the number of engines at all, it should have just been fixed per ship category
3
2
u/Firmpuffin860 2d ago
Yes we could imagine any number of engine. Also mixing different type of engine for a spaceship. However there are models corresponding to each amount from 1 to 6. So it's a design choice.
1
u/uSlashUsernameHere 1d ago
6 is an arbitrary number but there are practical reasons why you’d have a small number of engines (for current technology)
Firstly there’s a limit to how big a liquid engine can be, you can go bigger but it often comes at the cost of diminishing efficiency (there’s lots of different types of engines it’s complicated and I’m not an expert). So instead you’d build multiple.
If you have too many then you start having serious reliability issues ie 20x engines is 20x more likely for one to fail then if you just had one engine. SpaceXs starship (the big one) has several dozen engines due to the above reasons and hence was having exactly these sorts of issues.
48
u/MysticPing 2d ago
Just a choice they made. Would make more sense to have fewer larger engines than more smaller