Propeller Blade with Curved Tippet and Planar Front
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Solution Overview
Problem
Conventional propeller blades suffer from cavitation, efficiency losses, and noise due to radial fluid flow and eddies, which reduce their performance in moving fluids efficiently.
Innovation Solution
The design incorporates a curved tippet along the top of the propeller blade, redirecting radial flow axially and varying its radius of curvature to prevent eddies and reduce cavitation, with a planar front surface to minimize low-pressure zones and enhance fluid flow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional airfoil-shaped blades are used, then fluid can be moved through pressure differential, but cavitation occurs due to low pressure on the front surface
Solution Approach 1:
The patent inverts the conventional airfoil shape by placing the curved surface on the back of the blade instead of the front. This reversal eliminates the low-pressure zone on the leading edge that causes cavitation, while the curved back surface still generates useful suction force to move fluid forward.
Solution Approach 2:
The patent changes the geometric parameters of the blade surface, specifically making the front surface flat and the back surface curved. This parameter change fundamentally alters the pressure distribution, eliminating cavitation-prone low-pressure zones while maintaining fluid-moving capability through the curved back surface geometry.
2Power
If conventional airfoil-shaped blades are used, then thrust is generated through pressure differential, but efficiency is reduced due to radial flow and eddies
Solution Approach 1:
By inverting the airfoil shape and placing the curved surface on the back, the patent eliminates the formation of strong tip vortices and radial flows that occur with conventional blades. The flat front surface prevents flow separation and eddy formation, reducing energy losses.
Solution Approach 2:
The patent converts the potentially harmful radial flow and eddy formation into beneficial axial flow. The curved back surface guides the fluid smoothly, converting what would be energy-wasting vortices into useful thrust-generating flow patterns.
3Power
If conventional airfoil-shaped blades are used, then fluid movement is achieved, but noise is increased due to cavitation and eddies
Solution Approach 1:
The inverted airfoil shape with flat front and curved back eliminates the primary noise sources of conventional blades: cavitation bubbles forming on the leading edge and strong tip vortices. This geometric inversion creates quieter operation while maintaining fluid movement capability.
4Force
If conventional airfoil-shaped blades are used, then thrust is generated, but force losses occur due to radial flow
Solution Approach 1:
The patent inverts the conventional blade geometry to eliminate radial flow components that waste force. The flat front surface and curved back surface work together to convert radial flow tendencies into useful axial thrust, maximizing force efficiency.
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
This design increases propeller efficiency by reducing force losses, preventing eddies, and minimizing cavitation, resulting in improved thrust and reduced noise, while maintaining the same motor power, as demonstrated by increased boat speed and reduced rooster tail formation in testing.
Implementation Method 1
The curved tippet can reduce force losses, redirect the radial flow in an axial direction, and otherwise increase efficiency.
Implementation Method 2
The upper end can curve from the front surface toward the back surface. A radius of curvature of the upper end can vary along a length of the upper end.
Implementation Method 3
The motion of the fluid over a conventional airfoil-shaped blade causes a low or even negative pressure on the top of the airfoil... The planar front surface to minimize low-pressure zones and enhance fluid flow efficiency.
Implementation Method 4
The combination of the positive force acting on the back surface of the blade and the low or negative pressure on the front surface of the blade causes the blade to move fluid.
Implementation Method 5
When the speed of a blade through a fluid is great enough, the fluid can vaporize into a gas (i.e., cavitation). The low pressure region created by the airfoil shape of conventional blades can be especially prone to cavitation.
Data Source
AI summary
A propeller blade includes a body configured to extend radially from the hub of a propeller. The body can include a front surface, a back surface, a leading edge, and a trailing edge. The top of the body can form a tippet that generally transitions the front and back surfaces from extending in a generally radial direction to a generally axial direction. The tippet can reduce radial flow and force losses, redirect the radial flow in an axial direction, reduce the exit flow area of the propeller, and increase the inlet flow area of the propeller. The front surface of the blade can have a planar configuration that prevents or reduces the creation of low or negative pressure across the front surface of the blade and associated cavitation.