The present invention is a rotary device that may be adapted for use as a propeller assembly and electrical generator for aerial vehicles or other vehicles intended for fluid media. In one example, the device includes a ring assembly having a plurality of centrally linked blades coupled to a rotatable common hub. Rotary motion of the ring assembly is facilitated by coupling it to an opposed cylinder, opposed piston, internal combustion. The ring assembly includes components of an electrical power generating system so that electrical power is produced from the rotation of the ring assembly.