SAS won't hold heading

[KerikBalm]

I've been having a lot of problems with SAS not being able to hold a heading when using NEAR or FAR.

SAS tends to over correct when in atmospheric flight a little, resulting in a small oscilation... but when the oscilation gets just big enough, the SAS null point resets a little... and the result is I basically have to fly manually.

Is there any way to tweak this?

I'd really like to make it so SAS never resets its null point unless I toggle it - is there any way to do this? It is really really really *expletive deleted* annoying when SAS auto-resets the heading its trying to hold

[Taki117]

Apic of the craftwill help, but it sounds like you have too much control authority. Try using fewer control surfaces.

[nine_iron]

I solved this by using RCS Build Aid mod, very good and helped me fine tune my ship balance (even for things other than RCS).

[KerikBalm]

Well, this is sort of a generic problem I run into with many designs... its not an issue in space, but the SAS really annoys me in the atmosphere.

Maybe it is NEAR/FAR specific.

In a more mild form for many craft, I have a problem of getting the SAS to lock into a heading.

For example, I raise the nose to 45, although my heading is only 35 (AoA of 10)... and toggle SAS (tap the F key).

Instead of locking it in place, the nose drops as the SAS starts to give a small pitch input... but rather than increasing the pitch response to bring it back up, the white "SAS" light turns to those circular arrows, and the nose will slowsly drop for a while, before the SAS finnaly locks into a heading.

Basically, it seems when the heading deviates from the null setting by a certain amount, SAS automatically resets the null... I'm asking if there is anyway to stop this SAS behavior.

[KerikBalm]

SAS is freaking useless in the atmosphere with FAR installed... I have to fly everything completely manually, which is a major pain with "15 minute" ascents that take more like an hour due ot reduced frame rate, and 2 hours due to the need for quick loading....

[Frank_G]

Here you can see, how to correctly set up control surfaces:

I found this picture here on the forums, but i dont know the thread anymore, so i repost this picture. Rights remain with the author.

Edited October 13, 2014 by Claw
Spoiler for the image due to size.

[KerikBalm]

I know about aircraft design.

My question is very simple

HOW DO I STOP THE SAS FROM RESETTING ITSELF?

That is all I want to know.

[PikachuNL]

What I usually do to reset the SAS is tap "F", since that's the "hold for SAS" key, it will reset it. (With reset I mean, that it holds the current heading and AoA)

Edited October 12, 2014 by PikachuNL

[KerikBalm]

Yes, I do that, and it doesn't work.

Say I want to hold a pitch of 40 degrees, I pitch up to 40, hold it there a moment, tap "F"

The nose drops a bit, and SAS begins to apply a pitch correction, but it starts doing it too slowly, and the pitch continues to drop a bit... then the SAS decides to stop trying to hold the heading I set, and to set a new one at a lower pitch, often it will just have the pitch slowly drop for a while in the white "SAS" light turns to those circular arrows, before finally locking in at a much lower pitch, which results in a near zero AoA, and the plane descends, so I have to babysit it the whole flight tapping the pitch up key....

Meanwhile, it often won't reset when I enter control inputs, like when I'm turning or trying to correct a roll, so after I tap roll or yaw, it often undoes it... so I just fly the whole darn way manually.

And it can get quite annoying having to manage action groups for intakes, and engine toggles and rapier switches, all while flying manually or with an SAS the won't hold a heading.

Its particularly bad in one plane I have with a rapier cluster that overheats, so I have to tap the engine toggle pretty often (or yes, I could lower the thrust limiters... but I want full power on takeoff, particularly when carrying a full payload... and trying to fly manually while clicking on each engine to change the thrust limiter whith a really bad framerate is... well, not feasible)

This SAS behavior has been bugging me for a while... but trying FAR has just made it too annoying to not mention.

on another note, I wish we had a SAS setting that acted like SAS did in .18 when you had no ASAS module... it just stops rotation, and doesn't try to return to a given heading... I loved that SAS behavior with landers.

As I metioned earlier, the way SAS "fights" you unless you tap F after every keystroke (and often I have to hold F... but thats probably a result of the game running slow with very largeships), is also quite annoying, and this is true not just for planes, but also landers.

Are there any good mods out there to replace the stock SAS? I'm quite fed up with it.

[PikachuNL]

Don't know how SAS behaved in .18, but it sounds pretty good, better than the current SAS imo. What you could try tho is leaving the SAS off, and using the trim on your airplane (came with the Kornflakes) (Modifier + WASDQE)

[daffy]

SAS is a little more complicated with FAR installed. You probably shouldn't use it on launch. With FAR, the object is to build a vessel that will steer itself into orbit. Ideally, the only input you want to have to use is keeping your rocket on the 90 degree path. If you're using Yaw, then the rocket is unstable. (It's not easy, and I've crashed SOOOO many rockets in FAR!!) If I'm using a FAR installation, I turn on my SAS about 3-5K and after about a 15 degree incline (hopefully, on it's own without input). The first 100 m/s of your launch are going to tell you if it's going to be stable or not. Not a rocket scientist though, just watched some tutorials from people much brighter than I am. I found FAR to be a little frustrating, so I am using NEAR now which seems to have a little more forgiveness for the not-so-inclined naughts like me.

[lincourtl]

Not a rocket scientist though, just watched some tutorials from people much brighter than I am.

FAR puts the 'mental' in 'experimental' in more ways than one!

Is there a compendium of rocket-building and flying (not spaceplanes!) tutorials for FAR/NEAR that you know of? Maybe one tutorial you recommend in particular?

[Hodo]

SAS is a little more complicated with FAR installed. You probably shouldn't use it on launch. With FAR, the object is to build a vessel that will steer itself into orbit. Ideally, the only input you want to have to use is keeping your rocket on the 90 degree path. If you're using Yaw, then the rocket is unstable. (It's not easy, and I've crashed SOOOO many rockets in FAR!!) If I'm using a FAR installation, I turn on my SAS about 3-5K and after about a 15 degree incline (hopefully, on it's own without input). The first 100 m/s of your launch are going to tell you if it's going to be stable or not. Not a rocket scientist though, just watched some tutorials from people much brighter than I am. I found FAR to be a little frustrating, so I am using NEAR now which seems to have a little more forgiveness for the not-so-inclined naughts like me.

I have used FAR since I started playing KSP last year, and I can say it isn't that complex. But as for the SAS issue, I think it was changed somehow in .25, because I am having issues with it causing a "porpoising" affect on every plane I design, no matter how basic or complex.

[troyfawkes]

Two FAR/NEAR problems I get a lot:

1) Wobble, esp. on rockets with control surfaces. Hit SAS, hit Launch, rocket picks up a tiny bit of rotation, SAS over-corrects, then over-corrects back, then I give up and go back to manual control. I've never managed to solve this, so I just add extra control wheels and disable control surfaces on the aero parts.

2) In planes, I always have pitch problems (e.g. won't keep a heading). There IS a solution to this though and is more legitimate than using SAS. Set your flaps to a setting that keeps your flight level at whichever attitude you've chosen. Google KSP flaps and you can learn a bit more about it