Abstract: An aerodynamic lifting device comprises a chassis (200); a rotor (120) having a rotational axis (R) and a plurality of rotor blades (123) disposed in an annular ring about the rotational axis (R) supported by the chassis (200); and a torque transmission means (126,130,139) to provide tractive force for rotating the rotor (120). The torque transmission means (126,130,139) co-operates with at least one complementary and circumferentially extending drive surface (126a, 126b) of the rotor (120) to transmit tractive force as tangential forces and resultant torque sufficient to drive the rotor (120) and thereby generate lift. The aerodynamic lifting device may be used in airborne craft which may be deployed for waterborne use with a buoyant chassis (200), especially of toroidal shape, for elevating the rotor (120) above a water surface (300) during take off and landing.

Abstract: An aerodynamic lifting device comprises a chassis (200); a rotor (120) having a rotational axis (R) and a plurality of rotor blades (123) disposed in an annular ring about the rotational axis (R) supported by the chassis (200); and a torque transmission means (126,130,139) to provide tractive force for rotating the rotor (120). The torque transmission means (126,130,139) co-operates with at least one complementary and circumferentially extending drive surface (126a, 126b) of the rotor (120) to transmit tractive force as tangential forces and resultant torque sufficient to drive the rotor (120) and thereby generate lift. The aerodynamic lifting device may be used in airborne craft which may be deployed for waterborne use with a buoyant chassis (200), especially of toroidal shape, for elevating the rotor (120) above a water surface (300) during take off and landing.

Abstract: Disclosed is an airborne craft comprising an aerodynamic lifting device having a radial drum fan with an operating region intermediate the power loading (“y”) asymptotic region and the disc loading (“x”) asymptotic region of a power loading—disc loading characteristic for the lifting device. The radial drum or vertical axis fan comprises a fan with a rotor, the rotor having a rotational axis and comprising a plurality of rotor blades disposed in an annular ring about the rotational axis and a driving means for the rotor such that, on operation of the driving means, lift is generated.