Make differents skeletal mesh one in a blueprint

Hi, I’m a beginner and I have a little problem :
I have a tank which is separated in few pieces (Skeletal Mesh) and I want to make a blueprint with all the pieces so that I can place the full tank directly on the map. I’ve put all the pieces in the blueprint, the collision are working (the pieces collide with everything except the other tank pieces) and I’ve set all pieces to their socket. But the problem is that when I put the tank and then run the game, all the pieces fall and don’t stay in one (they all fall on the ground).

I don’t know what to do :confused: I ask you for help maybe you can help me :slight_smile: