Every airplane has its center of mass where its engine is set, since engine is the heaviest part. But in my plane, the center of mass is just at the geometric center of the plane model, so it does not properly fall down on the ground when in the air, not lke normal planes. It falls without chnaging its direction, e.g. if the plane was flying horizontally to the ground, it falls horizontally to the ground as well. I have PH_BOX, so it behaves as if it is a box, how to make gamestudio understand that the plane's tale is lighter than its engine part? I cannot make it PH_POLY, since it is a moving object.