A New Proposal of a Vertical Axis Propeller

A new vertical axis propulsion system with orbital paddles (called Bivortix system) is currently under review and in the experimental stage; this system is constituted by a pair of counter-rotating impellers, which provide directional thrust to 360°, allowing in each case a central thrust to axis, avoiding parasitic components. The system has been patented worldwide and so far have been made n.2 working prototypes, which have been tested in the towing tank of Trieste University and at the Vienna basin. A boat, called Proteus, has been built and the first propeller prototype has been installed and tested at full scale; the results obtained showed very advanced capabilities concerning the maneuverability, the stop and crash test and the good efficiency as regards the thrust. The results obtained as regards the efficiency were better than expected and the prototypes are currently being optimized. The system proves suitable to inland waterways, possessing a limited height of the blades outside the hull, the absence of rudders and the ability to perform maneuvers to 360°. Also the use in offshore activities can be suggested for its high efficiency and its maneuver capabilities. In the paper its functioning principles, the experimental processes carried out during the investigations and some significant results will be presented and discussed.