Can't enable physics on a static mesh (greyed out)

I have a skeletal mesh of a jet that is rigged, from that I made a static mesh to be used in a pawn blueprint so player can possess. I want to experiment with physics thrusters so need physics to be enabled. I have tried many of the solutions found in similar threads such as enabling simple or complex collision inside the static mesh details, enabling show all details in viewport, but nothing yet seems to make the switch not greyed out. Any suggestions is appreciated thanks.