A novel watercraft propulsion device is disclosed that includes multiple propulsive elements improving power and efficiency over prior designs. A self-adjusting variable pitch propeller is combined with a water jet and an exhaust driven turbine to provide optimal thrust and efficiency across the range of engine power, load and watercraft speed. Propulsive elements are axially disposed around a central drive shaft and exhaust port with the combined water jet/exhaust turbine disposed closest to drive shaft and the variable pitch propeller attached to the exterior of the water jet housing. A rotating duct is fixed to the propeller blades and rotates with the blades to reduce cavitation. Combined apparatus provides increased performance and efficiency over all watercraft speeds/load as well as additional safety due to the ducted propeller. Propulsor with an inducer, conical impeller and a diffuser also shown.

A novel watercraft propulsion device is disclosed that includes multiple propulsive elements improving power and efficiency over prior designs. A self-adjusting variable pitch propeller is combined with a water jet and an exhaust driven turbine to provide optimal thrust and efficiency across the range of engine power, load and watercraft speed. Propulsive elements are axially disposed around a central drive shaft and exhaust port with the combined water jet/exhaust turbine disposed closest to drive shaft and the variable pitch propeller attached to the exterior of the water jet housing. A rotating duct is fixed to the propeller blades and rotates with the blades to reduce cavitation. Combined apparatus provides increased performance and efficiency over all watercraft speeds/load as well as additional safety due to the ducted propeller. Propulsor with an inducer, conical impeller and a diffuser also shown.

The propulsion unit including a casing having an inner curved surface and an outer curved surface, at least one tire disposed within the casing within a duct defined by the inner curved surface and the outer curved surface, a first propeller and a second propeller having a plurality of blades extending from within the casing toward a center axis of the casing, and one or more motors housed within the casing, the one or motor being configured to operate the at least one tire, the first propeller, and the second propeller independently of one another. There is also provided a vehicle with one or more propulsion units of the present disclosure.

The propulsion unit including a casing having an inner curved surface and an outer curved surface, at least one tire disposed within the casing within a duct defined by the inner curved surface and the outer curved surface, a first propeller and a second propeller having a plurality of blades extending from within the casing toward a center axis of the casing, and one or more motors housed within the casing, the one or motor being configured to operate the at least one tire, the first propeller, and the second propeller independently of one another. There is also provided a vehicle with one or more propulsion units of the present disclosure.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A method and device is provided for increasing the efficiency of jet drives by recuperating effective power from the propulsion flow. A ducted propeller in the propeller housing, driven by a driving engine via a drive shaft, conveys the fluid for the jet drive out of the interior V.sub.i of a radial turbine. The fluid is accelerated axially and ejected backwards against the direction of travel. This creates thrust. Because the pressure in the interior of the turbine decreases, new fluid from the environment flows directly via the blades of the rotating radial turbine from the outside to the inside, thereby driving them. A guide apparatus is missing. The power of the radial turbine is transmitted via a transmission to the drive shaft of the propeller, which relieves the driving engine and increases the efficiency of the jet drive. The invention is particularly suitable for electric drives.

A method and device is provided for increasing the efficiency of jet drives by recuperating effective power from the propulsion flow. A ducted propeller in the propeller housing, driven by a driving engine via a drive shaft, conveys the fluid for the jet drive out of the interior V.sub.i of a radial turbine. The fluid is accelerated axially and ejected backwards against the direction of travel. This creates thrust. Because the pressure in the interior of the turbine decreases, new fluid from the environment flows directly via the blades of the rotating radial turbine from the outside to the inside, thereby driving them. A guide apparatus is missing. The power of the radial turbine is transmitted via a transmission to the drive shaft of the propeller, which relieves the driving engine and increases the efficiency of the jet drive. The invention is particularly suitable for electric drives.