Help on how to fix center of lift?

[Mytre]

Every craft I've built so far can never make it 10km's into the air because it always pitches or yaws, straight into the ground.

After debugging this problem, I came up to a conclusion that the problem was the center of lift. In the assembly bay, you can clearly see the blue ball is not centered onto the middle of the craft, along with it's center of mass and thrust.

Can somebody explain to me how I can fix the problem?

[SuperFastJellyfish]

The most stable craft(from a fuel drain standpoint) start with a CoL behind the CoM. Depending on how much fuel you have in front of the CoL will determine how stable your aircraft will be throughout it's whole flight. Liquid fuel depletes from the front to the back in KSP(without fuel lines). With this model you ideally want to make sure the CoL will always stay behind the CoM. My usual plane build will incorporate fuel tanks laterally along the CoM rather than a long fuselage to mitigate this effect.

[Spaceisbeautifulul]

You add wings. High tech illustration incoming.

Hope you can read the text, it just illustrates that the lift will move toward your wings.

DISCLAIMER: This is not where your center of lift & center of mass SHOULD be.

Edited June 5, 2013 by Spaceisbeautifulul
Disclaimer.

[rryy]

Actually, you should add more lift to the back of the craft or more mass in the front because your center of lift should ALWAYS be behind the center of mass. If possible, try to pump fuel from the back of the craft to the front and then into the engines. This way, the CoM will actually shift forwards instead of backwards. Another helpful tip to make sure the craft's CoM doesn't move behind the CoL would be to place a small truss or linear RCS port on the CoL so when you are in flight, you can see if the CoM has moved behind it (the camera is centered on the CoM, so zooming in all the way will show you your current CoM).