Stepped Surface Propeller
AssigneeTwin Disc, Incorporated
InventorPhilip Rolla
Life of this patent
Estimating the term…
Abstract
A marine surface propeller, and blade therefore, which is surface piercing and partially submerged, and includes a blade geometry that improves distribution of pressure and control to wetted and ventilated regions. Preferably, the feature has a positive step (ramp, cup, interceptor, indent or other geometric addition or intervention) between one fifth and four fifths chord length so as to create a high pressure peak or zone in what is now a low pressure zone on either the blade face or back or both and to create speed controllable wetted and ventilated regions.
Claims23
A blade of a surface piercing propeller for a marine craft comprising:
- a blade root securably attached to a propeller hub;
- a blade tip distal to the blade root;
- a blade face and an opposing blade back;
- a tapered leading edge and an opposing trailing edge;
- a trailing edge step feature on the blade face;
- and
- at least one geometric feature on either the blade back, the blade face, or both, that is located substantially mid-chord.
A surface piercing propeller for a marine craft surface drive comprising a plurality of blades wherein each blade is securably attached to a central propeller hub, the propeller comprising:
- a blade having:
- a blade root securably attached to the propeller hub;
- a blade tip distal to the blade root;
- two major and opposing surfaces:
- a blade back and a blade face wherein the blade face is subjected to a higher pressure from a fluid than the blade back while moving forward;
- two major and opposing edges:
- a tapered leading edge, and a trailing edge which is thicker than the leading edge;
- a trailing edge step feature on the blade face and at about the trailing edge;
- a second step feature on either the blade back or the blade face;
- and
- wherein the step features are located on the blade surface between the leading edge and the trailing edge, extending in a direction from the blade root to the blade tip, and rising from a local surface when traversing the blade surface from the leading edge to the trailing edge or from the trailing edge to the leading edge.
A blade of a surface piercing propeller for a marine craft comprising:
- a blade root securably attached to a propeller hub;
- a blade face and an opposing blade back, wherein one of the blade face and blade back is subjected to a higher pressure from the volume of water than the other surface thereby producing a force to move the marine craft;
- a tapered leading edge configured to enter the water first when the propeller is rotating to move the marine craft forward;
- an opposing trailing edge that is thicker than the leading edge;
- a first geometric feature on the trailing edge of the blade face surface that creates a first fluid pressure peak nearby, producing force to move the marine craft forward;
- a second geometric feature on either the blade back or the blade face that is located substantially mid-chord, wherein the second geometric feature creates a nearby second fluid pressure peak thereby producing force to move the marine craft.
Dependencies are inferred from the claim text.