Get Movement direction of physical Actor in Blueprint

Hey,
I want to rotate an arrow depending on his movement direction.
Does anyone know, how I could get it? I tried it with the velocity vector, but this vector is still 0 0 0 (because I am only moving the Arrow with a physical impulse, not the Blueprint).
It es an ActorBlueprint with one StaticMesh (the arrow).
Any ideas?
Thanks for answers