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.
Claims5
A propeller for a marine craft 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;
- wherein the blade face increases thrust up to 30% per area, versus a blade face without a step feature, when fully wetted.
Dependencies are inferred from the claim text.