First Space plane need help

[soulriver]

Hi just a few days ago i found a video on youtube about KSP and i really love this kind of games.But anyway the problem i am having is when i get to 9000-15000m with my space plane it starts being unstable and usually flips on it back but before 9000m the plane is pretty stable.What i think it happens is that when fuel from the front of the plane gets used the center of mass shifts to the back and it flips if you know what the problem could be or if it just build like crap and that why it not stable any solutions are appreciated.

[Jod]

A lot of questions about this recently. If it's a jet plane - you probably placed a lot of air intakes in the front. Move them as far back as possible, at high speeds Drag is the most common reason for instability. New players get stuck with this a lot since there is no marker or indication that Drag has its own center which depends on air intake placement.

[nhnifong]

More wings in the back, more struts. that outta do the trick Try to get the center of lift about a half-meter behind the center of mass, not aligned with it. Put the rear wheels on any massive object (not a wing!) thats more than a meter behind the center of mass. Finally, if it's squirrely, replace some of those control surfaces with plain wings. Even for a massive plane, two small control surfaces is plenty. Finally, you have two rudders are up on the tail. while that may look good, it's not going to fly good. change it to one rudder and hide it between those two big engine at the back, right in line vertically with the center of mass.