Propulsion system for a vehicle

A unmanned aircraft, comprising:

• a central supporting structure;
• a plurality of electric motors supported by the central supporting structure and having a toroid configuration, each of the plurality of electric motors having an annular stator and an annular rotor rotatable within the annular stator, the annular rotor of each of the plurality of electric motors encircling a central aperture;
• a plurality of propellers with each of the plurality of propellers being separately engaged with a corresponding one of the plurality of electric motors, each of the plurality of propellers having a central axis and one or more radial blades that are carried by the annular rotor of the corresponding one of the plurality of electric motors and extend into the central aperture thereof, each of the one or more radial blades starting from a wall of the annular rotor and ending at a blade free end which is located at a distance from the central axis;
• wherein the annular rotor and the annular stator of each of the plurality of electric motors forms a guide tube through which an airflow passes when the one or more electric motors are activated, and
• wherein the airflow passing through the guide tube of each of the plurality of electric motors is produced by the plurality of propellers, the plurality of propellers being configured so that the airflow passing through each guide tube converges towards a focusing area downstream of each guide tube.