Propeller Nut Curved Geometry for Exhaust Flow and Torque
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Solution Overview
Problem
Conventional propeller nuts do not adequately enhance boat performance, particularly in terms of acceleration and top speed, for motorized boats with through-hub exhaust propellers.
Innovation Solution
A propeller nut with a unique shape and configuration, featuring a frustoconical leading portion, a conical or conoidal trailing portion, grooves, notches, and a rough surface, which securely engages the drive shaft and allows efficient exhaust flow, improving propulsion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional hexagonal propeller nut is used, then the structure is simple and easy to manufacture, but the boat performance (acceleration and top speed) is not improved
Solution Approach 1:
The propeller nut employs a frustoconical leading portion and a conical or conoidal trailing portion with curved outer surfaces. The conoidal shape specifically features a curved longitudinal cross-section that promotes turbulent fluid flow, replacing the conventional flat hexagonal shape with aerodynamically optimized curved surfaces to enhance boat performance.
Solution Approach 2:
Different portions of the propeller nut have distinct geometric features optimized for specific functions: the frustoconical leading portion for flow direction, the conoidal trailing portion with curved surfaces for turbulence promotion, grooves cut into the trailing portion for enhanced fluid dynamics, and notches at the maximum outer circumference for performance optimization. Each local feature serves a specific hydrodynamic purpose.
2Productivity
If the propeller nut has a frustoconical leading portion and conoidal trailing portion with grooves and notches, then fluid flow is promoted and performance improves, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes specific geometric parameters of the propeller nut including the frustoconical angle of the leading portion, the conoidal curvature of the trailing portion, the depth and spacing of grooves, and the positioning of notches at the maximum outer circumference. These parameter optimizations enhance propulsion efficiency while maintaining manufacturability through precise geometric control.
3Force
If the propeller nut is designed to promote turbulent fluid flow, then torque and acceleration improve, but the device complexity increases
Solution Approach 1:
The conoidal trailing portion with its curved outer surface is specifically designed to promote turbulent fluid flow, which enhances torque generation. The curved geometry creates controlled turbulence that improves propulsion force without requiring additional mechanical components.
Solution Approach 2:
The propeller nut utilizes fluid dynamic principles by designing the frustoconical and conoidal surfaces to manipulate water flow patterns. The grooves and notches create specific flow regimes that enhance torque through hydraulic effects, leveraging the properties of the fluid medium rather than adding mechanical force-generating elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The propeller nut enhances boat acceleration and top speed by promoting turbulent fluid flow and focusing motor exhaust, resulting in improved torque and performance characteristics.
Implementation Method 1
the trailing portion of the propeller nut comprises a rough or irregular surface to promote turbulent fluid flow over the trailing portion
Implementation Method 2
The frustoconical part extends outwardly from the nut part to a maximum outer circumference of the propeller nut. The trailing portion extends from the maximum outer circumference to a trailing end of the propeller nut. The trailing portion has a conical or conoidal outer surface.
Data Source
AI summary
A propeller nut designed to replace a conventional hexagonal nut to secure a boat propeller to a motor. The propeller nut includes a leading portion and a trailing portion. The leading portion has a nut part having internal threads sized and configured to engage external threads of a drive shaft and to secure the boat propeller about the drive shaft and a diverging part extending outwardly from the nut part to a maximum outer circumference. The trailing portion extends from the maximum outer circumference to a trailing end of the propeller nut, wherein the trailing portion has an outer surface that converges from the maximum outer circumference to the trailing end.