Try my TUMBLING ship

[Hiatsu2k8]

I have this ship, its kind of big and it always starts to flip end over end as I launch. I built it after another ship that I downloaded off the forum, except I made a bit bigger for longer flights. Check it out see if you can tell me what the problem is.

Plugins are the MechJeb and MAPSAT

[Ziff]

The problem is you have too many tanks stacked vertically. As they use up fuel the center of mass shifts towards the top of the vehicle making it uncontrollable and likely to flip over on its end.

[Hiatsu2k8]

thanks didn't know that. Thank you

[thevegimobil]

I have this problem on my rocket launching a spaceplane vertically... If you can overcome it I'd love to know how

[EndlessWaves]

I have this problem on my rocket launching a spaceplane vertically... If you can overcome it I'd love to know how

There are several things that can cause this but for a spaceplane make sure your build your rocket around the spaceplane, sticking it up top is likely to cause instability because the wings and control surfaces are much further from the centre of mass.

[draeath]

... and the lift from your wings (if you have any) will be pushing on the rocket, too. You either need to find a way around this or compensate. (bunch of RCS linear near the spaceplane, dorsal side?)

[thevegimobil]

Centre of lift is shown as just being the canards... The wings seem to have no effect on the position of lift.... I have put ailerons on my Srb and main engine but when I turn sas off and go for roll it goes...