Wobbly rockets

[Guest]

I have designed a few wobbly rockets lately, and realized the problem was ADV SAS. It would push the rocket to one side to correct, over correct, then re correct the false correction over and over and over. Thus it wobbles. Anyone know how to use ADV SAS without this problem? 4 SAS BTW

Rocket

[Epsilon]

As I recall, having more than one Adv. SAS on your ship will cause problems such as you described. Try using only one module. The power of all the modules is causing your issues.

[Kosmo-not]

Are there struts connecting the outer stacks to the inner stack? The lack thereof usually causes wobbliness.

1 ASAS is all you need for any rocket. SAS, on the other hand, does have some cumulative benefit.

[Feragorn]

One ASAS for the entire rocket, one SAS per stage. Keeps things solid as a rock.

[Ydoow]

I thought even 1 ASAS would cause this issue. Was it fixed and I wasn\'t aware?

[vexx32]

Using 1 ASAS, it will still sometimes overcompensate, but it usually isn\'t much of a problem unless you use RCS overmuch.

[Feragorn]

Mmm. When ASAS uses the normal SAS modules, it doesn\'t often wobble out of it\'s own socket. I\'ve never had a rocket disintegrate using that technique, but flaps and RCS can get uncontrollable quite quickly. Also, if using RCS, place one set of thrusters at the top, and one at the bottom. That\'ll help too.

[MFToast]

Mechjeb will hold a heading for you without this problem, give it a try. Pretty stable.

[Ferrit]

Another thing to remember is that the more control surfaces/RCS units you have, the more the rocket might over-correct. Each winglet/RCS cluster will add it\'s own turning force so with lots onboard the small corrections by ASAS can lead quickly to an oscillating rocket. I tend to leave RCS off at low altitudes, relying on the winglets to do their thing and if possible drop them off with an early stage to save mass and prevent any extra force from them. In short, use the least of anything you can get away with.