Propulsion system

A rotor blade is provided for a rotor having a rotor turning axis, the rotor blade having a blade aerodynamic section and a blade root extension. The blade root extension extends towards the rotor turning axis from the blade root of the blade aerodynamic to at least a free blade inboard edge, and includes a trailing section, a leading section and an engagement section. The engagement section is configured for being engaged to a rotor hub. The trailing section is at least partially co-extensive with respect to the engagement section in an inboard direction parallel to a blade span axis of the rotor blade. A rotor arrangement includes a plurality of such rotor blades and the hub element, and a propulsion assembly includes such a rotor arrangement and a drive unit.