Various examples of a high-speed omnidirectional fully-actuated underwater propulsion mechanism are described. In one example, a propulsion system includes two decoupled counter-rotating rotors centered on a main axis, with each rotor comprising a plurality of pivotable blades projecting radially from the main axis, a servo-swashplate actuation mechanism comprising a plurality of servos and a linkage assembly connected from the servos to the pivotable blades, a blade-axis re-enforcing flap adapter comprising a plurality of stationary flaps, with the blade-axis re-enforcing flap adapter being positioned in a region between the two decoupled counter-rotating rotors centered on the main axis, and a controller. The controller can be configured to calculate control parameters, compensate a first control parameter among the control parameters to reduce cross-coupling of an unwanted force generated by drag forces on the two decoupled counter-rotating rotors, and generate a control signal for each of the servos based on the control parameters.

Various examples of a high-speed omnidirectional fully-actuated underwater propulsion mechanism are described. In one example, a propulsion system includes two decoupled counter-rotating rotors centered on a main axis, with each rotor comprising a plurality of pivotable blades projecting radially from the main axis, a servo-swashplate actuation mechanism comprising a plurality of servos and a linkage assembly connected from the servos to the pivotable blades, a blade-axis re-enforcing flap adapter comprising a plurality of stationary flaps, with the blade-axis re-enforcing flap adapter being positioned in a region between the two decoupled counter-rotating rotors centered on the main axis, and a controller. The controller can be configured to calculate control parameters, compensate a first control parameter among the control parameters to reduce cross-coupling of an unwanted force generated by drag forces on the two decoupled counter-rotating rotors, and generate a control signal for each of the servos based on the control parameters.

A directed thrust propulsion system has a central hub and at least three blades that extends outward at a rake angle between about 20 to 70 degrees. Each blade is shaped as a portion of a cylindrical surface, in which concave side forms the blade face and is facing in direction of thrust generated by rotating the hub. The convex side of the blades minimizes drag in the water that resists forward motion while the concave shape and tilted end portions directs the thrust inward toward the extension of the hub's principal axis rearward. The directed thrust propulsion system may be deployed on inboard and outboard motors for all manner of watercraft to increase efficiency above 10 knots speed.

The present invention involves a method for manufacturing a blade (1) for a propeller, which blade (1) has a leading edge (2) and a trailing edge, the method comprising the steps of: forming a conduit in the blade (1), making a plurality of holes (7) through which the conduit (6) communicates with the exterior of the blade (1), and providing a blade blank having an edge part receiving surface (4) extending along at least a major part of the leading edge (2) of the blade (1) to be manufactured, wherein forming a conduit (6) comprises building up an edge part (3) onto the edge part receiving surface (4) by a wire-based additive manufacturing process, wherein the additive manufacturing process is adapted to form the conduit (6) at least partly delimited by the edge part (3) and extending along the leading edge (2) of the blade (1) to be manufactured.

A duo propeller disclosed having a forward propeller having increased loading distribution and high swirl near the tip. The duo propeller has an aft propeller with a more optimal loading distribution that can cancel the high tip swirl from the forward propeller. The duo-propeller an enhanced ability for the aft propeller to capture the energy lost to the swirling flow of the forward propeller's outflow.

A propeller having a central post to which one or more blades are connected. The blades are disposed and configured to pull air in from the propeller's sides toward the propeller's axis of rotation to create pressure in an area in the vicinity of the center of the propeller's rotating axis for generating thrust.

A ship screw, pump screw or turbine screw for use under water or another liquid, comprising a front side and a rear side, wherein water or another liquid is forced from the front side to the rear side in use, and comprising a hub and at least two blades extending from said hub, wherein the blades are substantially helical/spiral shaped, their effective surface area increasing from the front side toward the rear side.

A ship screw, pump screw or turbine screw for use under water or another liquid, comprising a front side and a rear side, wherein water or another liquid is forced from the front side to the rear side in use, and comprising a hub and at least two blades extending from said hub, wherein the blades are substantially helical/spiral shaped, their effective surface area increasing from the front side toward the rear side.

A propeller. The blades of the propeller are characterized by a blade center axis which corresponds to a generator line of a cone to which the blade, or blade thrust surface, conforms. The propeller hub is fixed to the blade at the root, in line with the blade center axis, such that the hub axis and blade center axis lie in the same plane, and the leading edge of the blade is positioned forward (referring to the upstream direction of movement caused by the propeller) of the trailing edge of the blade.

One embodiment of submerged superventilated blades (101) that provide hydrodynamic force to a vessel or aircraft (117) that can lift it above the surface of the water (106) at high speed by creating thrust with a wetted high pressure surface (111), the low pressure surface (112) being covered with a gas filled void in the liquid, thus preventing sudden loss of lift as speed increases due to cavitation or surface venting. Other embodiments are described and shown.