ATTACHED DUCT PROPELLER SYSTEM

An attached duct propeller system may include at least one propeller blade having at least one blade tip. A duct having an inner wall may surround the at least one propeller blade. The at least one propeller blade may attach to the inner wall of the duct. In certain embodiments, the attached duct propeller system may include a propeller shaft attached to a bore of the at least one propeller blade. In certain embodiments, the at least one blade tip may be trimmed to allow alignment within the duct and allow for the attachment of the at least one blade to the inner wall of the duct. The attached duct propeller system may be used for vehicles that use at least one propeller for propulsion.

DETAILED DESCRIPTION OF THE INVENTION

Broadly, an embodiment of the present invention provides an attached duct propeller system that may include at least one propeller blade having at least one blade tip. A duct having an inner wall may surround the at least one propeller blade. The at least one propeller blade may attach to the inner wall of the duct. In certain embodiments, the attached duct propeller system may include a propeller shaft attached to a bore of the at least one propeller blade. In certain embodiments, the at least one blade tip may be trimmed to allow alignment within the duct and allow for the attachment of the at least one blade to the inner wall of the duct. The attached duct propeller system may be used for vehicles that use at least one propeller for propulsion.

The present invention may improve thrust and efficiency, which may also reduce fuel usage. The present invention may have a duct surrounding at least one blade that may prevent thrusted water from being spun outward away from the centerline of thrust. A marine vessel or the like that is so equipped may go faster at the same rpm versus an ordinary propeller since water, or any other liquid, may be focused into a tight column, thereby increasing thrust and efficiency.

As is illustrated inFIGS. 1 through 8, the present invention may include at least one propeller blade10. The at least one propeller blade10may attach to a propeller shaft20. The at least one propeller blade10may have a center bore24. The center bore24may have a plurality of splines26. The propeller shaft20may be a splined propeller shaft20so that the splines26along the center bore24may line up with the splined propeller shaft20. The propeller shaft20may be attached to an engine/transmission18. The engine/transmission18may be attached to a boat or the like. A duct12may surround the at least one propeller blade10. The duct12may have an outer wall16and an inner wall14. At least one propeller blade tip22may be trimmed so that the at least one propeller blade10may fit within the inner wall14of the duct12. The trimmed end of the at least one propeller blade tip22may be a flat surface parallel to the centerline of thrust. The at least one propeller blade10and the duct12may be secured to the propeller shaft20. A nut28and washer30, or the like, may be used in order to secure the duct12and at least one propeller blade10to the propeller shaft20.

A standard marine propeller spins and forces water rearward, but a percentage of the thrust is spun ‘out’ or ‘away’ from the tips of the propellers instead of being directed rearward to propel the vessel. By encasing the propeller in its own attached duct, thrust water may not escape outward and may be forced and focused to travel through the duct. This narrowing of the fluid trajectory increases the amount of water that may be converted for thrust for the very same revolutions per minute (rpm). Since more water may be directed for thrust, a vessel so equipped may travel faster for the same rpm. This may also translate to lower fuel consumption and greater efficiency. The attached duct may also stiffen the propeller blades, thereby reducing flex. Since the propeller blades may not flex, they thrust a greater volume of water, which also increases thrust and efficiency.

A method of making the present invention may include the following. In certain embodiments the diameter of a marine propeller blade10may be measured, such as approximately 14.25 inches. In this particular embodiment, an approximately ⅛ inch thick substantially cylindrical duct12, approximately 8 inches high may be manufactured with an inside diameter equal to approximately ¾ inches less than the diameter of the selected marine propeller such as 13.5 inches. The remaining approximately 0.375 inches of the each propeller blade tip22may be removed, leaving a flat surface parallel to the centerline of thrust. This may also leave the total diameter of the propeller blades and duct the same as the original propeller blades by itself. The substantially cylindrical duct12may then be placed around the shortened propeller blades10, approximately 3 inches from a hub. Each blade tip may be welded to the inside of the substantially cylindrical duct12. The completed assembly may then be balanced and painted. In certain embodiments, thicker propeller blades may require less trimming in order to produce a sufficient flat surface for the welding of the duct. In certain embodiments, the attached duct propeller system may be made from scratch as well, and in this situation, welding may not be required as the molding or machining process may fabricate a complete attached-duct propeller as one solid piece of metal.

In larger applications such as tanker ships, container ships, passenger ships, naval and coast guard ships, and the like, the substantially cylindrical duct may also be fabricated in sequential sections and attached by welding, riveting or the like, in increments until a fully enclosed duct may be completed.

In certain embodiments, the height of the substantially cylindrical duct12and distance from the hub may be changed to accommodate a variety of engine configurations. In certain embodiments, similar substantially cylindrical duct12may be fabricated and attached to standard aviation propellers to increase thrust and efficiency.

A method of using the present invention may include the following. Replacing a standard marine propeller with an attached duct propeller system, a boat may accelerate faster and have a higher top speed. The boat may use less fuel and go farther per tank. The attached duct propeller system may reduce pollution and greenhouse gases. In military applications, naval and coast guard ships may perform better and be more fuel efficient, saving millions of gallons of fuel. In commercial applications, tanker ships, container ships, tug boats, cruise ships, and the like may use far less fuel. The existing propeller may be modified with no changes necessary to the vessel or aircraft superstructure.

In certain embodiments, the attached duct propeller system may be applied to aircrafts32. At least one aircraft propeller blade34fitted with an attached substantially cylindrical duct12may also benefit from increased thrust, increased efficiency, and reduced fuel usage. A center bore40of the at least one aircraft propeller blade34may attach to the aircraft propeller shaft36. The aircraft propeller shaft36may attach to the aircraft engine38so that the aircraft engine38may power the rotation of the at least one aircraft propeller blade34. By forcing the thrusted air through the substantially cylindrical duct12, a higher efficiency may be achieved over a standard aircraft propeller. By encasing the propeller in its own attached duct12, thrust water may not escape outward and may be forced and focused to travel through the duct. This narrowing of the air trajectory increases the amount of air that may be converted for thrust for the very same revolutions per minute (rpm). Since more air may be directed for thrust, a vessel so equipped may travel faster for the same rpm. This may also translate to lower fuel consumption and greater efficiency.

Although the present embodiment of the invention may be illustrated installed on a typical small boat engine, it should be noted that the invention may be configured and installed on any type of vehicle that uses at least one propeller for propulsion including but not limited to ships, small watercrafts and aircraft as known by those in the art.