Propulsion system for an aerial vehicle

A propulsion system for an air vehicle (1) that comprises at least one differential velocity fan (4), housed in and concentrically arranged in a fan housing (30), wherein the differential velocity fan comprises a rotor hub (12), by which said rotor hub fan blades are attached and stretch substantially radially out from the rotor hub, at least one power unit (2) and at least one power transmission device (3) for transferring power from the power unit to the differential velocity fan, and that said propulsion system is characterized in that said propulsion system comprises said at least one velocity fan or fans that are arranged with their rotational axis perpendicular to a longitudinal axis of the air vehicle and that the velocity van has a length, b, and a diameter, D, and that b<=D, wherein said propulsion system comprises at least one forward air duct (41) and at least one rearward air duct (42) where air is led from air intakes (5;

• 16) rearwards in the air vehicle through the forward air duct, the forward air duct widening in cross section causing the speed of the air to decrease and static pressure to increase, thereafter the air is led axially into the differential velocity fan which rotates and pushes the air out radially from the fan into the rearward air duct, the rearward air duct successively decreasing in its cross section causing the speed of the air to successively increase in the rearward air duct and thereby decreasing static pressure, further a portion of the air is forced out through an opening (13) on an upper side of the air vehicle giving an energized airflow (14) on the upper side of the air vehicle, while the bulk part of the air passes through jet nozzles (6), each nozzle is regulated by a nozzle flap/spoiler (11) and an upper nozzle flap (10) said nozzles generate drag by the passage of air from the differential velocity fan to and through the nozzles.