Applies to KSP versions: 1.0.4 and newer. TL/DR: Among other things, this post explains why your reentering Space Shuttle replica and other winged craft can be unstable even though you built it with Center of Lift (CoL) behind Center of Mass (CoM). It also explains how you can improve general stability of any winged craft with Angle of Incidence (AoI), while at the same time making the craft very SAS friendly, and able to fly straight without SAS. The difference between CoL and Ae