Abstract: A mechanical device consisting of two horizontal shafts (4 & 5) in cruciform each rotating axially within two sets of bearings (6), each set positioned near either end and interfaced upon a rotor base (10) which itself is fixed to a vertical power shaft 11 centrally. The powershaft rotates within two other sets of bearings (12). The horizontal shafts are each bolted to and pair of aerofoil section wings (2 & 3) through their respective flange plates (7), each wing being regulated axially by a cam (8) in 90 degree relationship. At any given moment, one wing will always resist (2b & 3b) the external power source (1) of wind or water current thereby bringing about rotation of the powershaft, whilst the opposite wings (2a & 3a) will transiently adopt a free flow posture.

Abstract: A mechanical device consisting of two horizontal shafts (4&5) in cruciform each rotating axially within two sets of bearings (6), each set positioned near either end and interfaced upon a rotor base (10) which itself is fixed to a vertical power shaft 11 centrally. The powershaft rotates within two other sets of bearings (12). The horizontal shafts are each bolted to and pair of aerofoil section wings (2&3) through their respective flange plates (7), each wing being regulated axially by a cam (8) in 90 degree relationship. At any given moment, one wing will always resist (2b & 3b) the external power source (1) of wind or water current thereby bringing about rotation of the powershaft, whilst the opposite wings (2a & 3a) will transiently adopt a free flow posture.