What are the benefits of tweaking thrust limits?

[Panzerbeard]

So, I've finally had a chance to play around with .23, and one of my favourite features is the tweakables system. I was using the engine thrust tweaks to keep my TWR at around 2 for my lifter stage, but I can't figure out if there's any benefit to doing this after your ascent stage? During ascent it's useful, since high-TWR ascents will just lose out to atmospheric and gravitational drag, but is there any real benefit once you're in space? Unless I've misunderstood how engines work, limiting the thrust isn't actually going to change the ISP or dV available to you, right? As far as I can tell, the only reasons you'd want to limit thrust is for a more efficient ascent stage, and keeping the CoT in asymmetric rockets in the right place. Is there anything I'm missing?

Oh, also, something I've been meaning to ask for months.. is there any way to make the dark... darker? Whenever I watch Scott Manley's videos and he's on the night side, the ship is barely visible and shadows seem to work properly. On mine it's always been fairly bright, like this:

Whenever I'm looking at the dark side of a rocket, it always seems to be illuminated too, as if the light is just curving around. I've tried increasing the Shadow Cascades setting in the graphics options, but it doesn't seem to have any effect, is this a mod or some hidden setting in the config file, or what? I know it isn't a mod issue, since my game's been like that for as long as I can remember, long before I started using mods.

Cheers,

Ash

Edited December 27, 2013 by Panzerbeard

[Anton P. Nym]

I haven't really delved into the tweekables much yet, but I gather that thrust limiter is useful for solids and for engines prone to overheat. I may tinker with them when I get some time over the holidays... but until I tinker a bit more that's my best guess.

-- Steve

[Jenteb07]

Well, it can be useful in the case of an asymmetrical payload. By tweaking the thrust you can move the center of thrust to the center of mass.

That's all I guess

[blizzy78]

During ascent it's useful, since high-TWR ascents will just lose out to atmospheric and gravitational drag, but is there any real benefit once you're in space?

In space there isn't any benefit to thrust limiting, assuming no off-center thrust.

[Kilmeister]

Asymmetrical rockets. Makes it a lot easier to slap a rocket onto the bottom of a spaceplane and take it to orbit.

[DerekL1963]

In space there isn't any benefit to thrust limiting, assuming no off-center thrust.

Actually, there is. I use RemoTech2, and thus have an orbital communications constellation, and the birds in the constellation need their orbits fine tuned now-and-again. Before tweakables, you either needed a very fine hand on the throttle, or RCS, or ion engines. RCS means hauling an additional tank along, and it's harder to make gross corrections. Ion engines appear late in the tech tree, they mean hauling an additional tank along, and it's also much harder to make gross corrections. My current design uses a LV-909 and two LV-1R's. The -909 is used to boost into orbit, and for gross corrections (lowering the peri or raising the apo to 'walk' the bird a large distance to the east or west), and is disabled via right click when not needed. The -1R's are thrust limited to 10%, and are used for fine tuning the orbits (in the sub meter per second range or correcting their orbital period to the exact second). Both draw from the same pool of fuel, simplifying the vehicle's design, and both are available fairly low in the tech tree.

So, a special purpose need, but a need none-the-less.

[worir4]

A1: Its useful for balancing rockets; ever tried to build a shuttle? It can help with having enough thrust to keep your rocket up right but not tip over.

A2: It looks quite dark to me, Maybe its your monitor. I had a problem with mine where it was too dark. All i did was change the gamma and it worked. P.S Have you used a modded celestial sphere becuase it looks alot cooler than mine, if so could you send me a Link?

[Panzerbeard]

A2: It looks quite dark to me, Maybe its your monitor. I had a problem with mine where it was too dark. All i did was change the gamma and it worked. P.S Have you used a modded celestial sphere becuase it looks alot cooler than mine, if so could you send me a Link?

Eh, possibly, I'll try changing around the monitor/nvidia display settings, but I have them set below default usually anyway. I'll mess around and see if I can't get it looking better

I'm using Shaw's Texture Replacer (works much better than Universe Replacer, in my experience, I get no noticeable framerate loss with it) with Rareden's Skybox and Klakh's 2k pack for the planets and moons. If you' use Texture Replacer instead of Universe Replacer you'll need to fiddle around converting the textures to .tgas, but I find it's worth it

[GluttonyReaper]

Oh, also, something I've been meaning to ask for months.. is there any way to make the dark... darker? Whenever I watch Scott Manley's videos and he's on the night side, the ship is barely visible and shadows seem to work properly. On mine it's always been fairly bright, like this:

Whenever I'm looking at the dark side of a rocket, it always seems to be illuminated too, as if the light is just curving around. I've tried increasing the Shadow Cascades setting in the graphics options, but it doesn't seem to have any effect, is this a mod or some hidden setting in the config file, or what? I know it isn't a mod issue, since my game's been like that for as long as I can remember, long before I started using mods.

Cheers,

Ash

From what I remember, Youtube tends to make things darker generally.

[Specialist290]

It might be your screen's display settings as well, since that screenshot looks rather dark on my monitor.

[Pineapple Frenzy]

I find the thrust limiter is very useful for landing on bodies with low gravity. Quite often my landers have TWRs in excess of 3:1. Reducing maximum thrust gives me finer control of the lander's descent.

[barrenwaste]

Think of Ion engines. They need a steady feed of electricity, thrust limiting can help provide a wide and even thrust without using more electricity than your craft can produce. It can also help in the case of inexperienced pilots. Thrust limiting can ensure that they don't run out of fuel while trying to set up and use maneuver nodes by giving the player more time during the maneuvers. I can also see another aspect with unbalanced craft. Often, a craft that is unbalanced is fine at lower acceleration but becomes uncontrollable at higher acceleration. Limiting the thrust can keep the craft inside the safe zone.

[LostElement]

I wish the tweakables for boosters were a bit different. Like for a mainsail has 1500 thrust. A skipper has 650. 650 is too low and 1500 is too much. I wish you could take the mainsails 1500 and tweak it down to 1000. Instead of 75.5 or 90.

[DeMatt]

I wish the tweakables for boosters were a bit different. Like for a mainsail has 1500 thrust. A skipper has 650. 650 is too low and 1500 is too much. I wish you could take the mainsails 1500 and tweak it down to 1000. Instead of 75.5 or 90.

...that's a percentage, not an absolute value. So tweaking a Mainsail down to 66.5 will limit its maximum thrust to 997.5 kN.

[SRV Ron]

I wish the tweakables for boosters were a bit different. Like for a mainsail has 1500 thrust. A skipper has 650. 650 is too low and 1500 is too much. I wish you could take the mainsails 1500 and tweak it down to 1000. Instead of 75.5 or 90.

Divide 1500 into the target thrust. In your example, get as close to 66.7 as you can. However, consider using a cluster of LV-30 or LV-45 in place of the one heavy Mainsail, or mod engines such as Nova Punch and KW Rocketry.