Why is this rocket drifting to the site at launch?

[melenkurio]

I build this rocket before and it worked perfectly but I had to reinstall KSP and all my ships were gone. I rebuild this rocket and now it always drifts to one site if I launch it even though I cant find any unbalanced stuff on it.

[tjoreilly]

It looks to me that as your rocket depletes its fuel in the first stage that it begins to become too top-heavy for the SAS units to correct. Also, I could be wrong, but I mostly use the SAS units to mitigate craft rotation. So, I reworked your craft a bit, replacing all of the SAS units with a single ASAS. Your craft climbs straight as an arrow until about 60km. Then, the rotation starts.

[melenkurio]

Thanks for the modified version but it still drifts to the site if I launch it :/.

[melenkurio]

Well I got a similar one to work already but I have some questions:

How should I build a big rocket without tricouplers? If I just stick the fuel tanks side by side together without tricouplers the engines overheat themselves. Tricouplers give them some space inbetween. Could you maybe show me a similar design like my rocket but without tricouplers?

[Millst0ne MK II]

Don\'t build a big rocket.

Less is more. Pod+ASAS+RCS tank+RCS thrusters+decoupler+plus 4 tanks+6 strap on boosters=easy orbit, and some room to play around up there!

[VincentMcConnell]

If you want, I\'ll make you a capable Mun and Minmus craft right now.

Here. Karma-II Rocket.

Plenty of power and fuel to get you to any celestial body and back

https://dl.dropbox.com/u/76061308/Karma%20II%20Rocket.zip

[Markus Reese]

I made a couple changes and was able to get it stable. First I made the central initial stage the slightly smaller 45 gymbal rockets, helps keeping alignment and pulled off the outer SAS. I pulled out the command module SAS for an advanced SAS. I put three fuel tanks instead of the four on the lander bay to help balance. There is still some drift, but that was caused by some flexing in the booster engines.

[melenkurio]

If you want, I\'ll make you a capable Mun and Minmus craft right now.

Here. Karma-II Rocket.

Plenty of power and fuel to get you to any celestial body and back

https://dl.dropbox.com/u/76061308/Karma%20II%20Rocket.zip

Thanks I already had some smaller rockets like these. I just wanted to make a really big one thats still able to get into space and I thought tricouplers are the way to go. I think its possible but mine wasnt very efficient thats true.

EDIT: Okay maybe I have to reinstall my game even your rocket is drifting into a random direction and crashing after 10 seconds :/ I think something may be bugged for me

[Markus Reese]

I wonder if there is some control input that your game file is receiving causing it to turn. The best stable test is a short single column rocket. Very simple for just to space and back, see if it is banking. There is something else that can happen on older machines, and is an error when loading up the rocket that can cause thrusters to break off.

When you load the rocket, do you hear the sound of say a stage separation and next time you go to it, does it ask you to clear the launch pad? If a nossle is breaking off, you will end up with uneven thrust. Also see if there is any failures in your mission report to see if any failures are occuring before launch.

[UmbralRaptor]

Well I got a similar one to work already but I have some questions:

How should I build a big rocket without tricouplers? If I just stick the fuel tanks side by side together without tricouplers the engines overheat themselves. Tricouplers give them some space inbetween. Could you maybe show me a similar design like my rocket but without tricouplers?

I\'m confused -- I\'ve been making various big clustered rockets with no overheat issues since 0.13.