Tapered Hub Propeller Reducing Drag via Waste Gas Induction
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Solution Overview
Problem
Existing propellers suffer from increased drag and reduced thrust due to turbulence caused by the interaction of waste gas and water flow, and have high manufacturing costs and structural weaknesses due to separate components that corrode in seawater.
Innovation Solution
A propeller design with a hub and equiangularly disposed blades, where the outer periphery of the tail portion's distance from the center axis decreases towards the outlet, eliminating the need for an end cover, allowing waste gas to draw water and reduce drag, while being an integrated design for cost reduction and enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the end cover is gradually expanded in external diameter, then the structural strength is improved, but the water flow interferes with waste gas causing turbulence and increasing drag
Solution Approach 1:
Instead of expanding the end cover outward (conventional design), the patent inverts the approach by creating an inwardly tapering tail portion where the outer periphery distance from the center axis gradually decreases toward the outlet. This reverse geometry prevents water flow interference with waste gas exhaust, eliminating turbulence and reducing drag while maintaining structural integrity.
2Ease of manufacture
If the end cover and hub are manufactured individually and engaged, then the manufacturing flexibility is improved, but the manufacturing cost increases and the junction corrodes in seawater
Solution Approach 1:
The patent merges the end cover and hub into a single integrated propeller body, eliminating the separate end cover component and its engagement junction. This integration reduces the total number of parts, eliminates corrosion-prone junctions in seawater environments, simplifies manufacturing processes, and reduces overall manufacturing cost while maintaining all necessary functional capabilities.
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 design enhances propulsive force by smoothing water flow and reducing drag, lowers manufacturing costs, and prevents corrosion, thereby improving structural strength and efficiency.
Implementation Method 1
the waste gas exhausted out of the outlet of the hub will draw the water flowing along the outer periphery of the tail portion
Data Source
Figure 1~2
Figure 3
AI summary
A propeller (20) for a boat includes a hub (30) having a tail portion (36) with an outlet (34), and a plurality of blades (40) equiangularly disposed on the hub (30). The outer periphery of the tail portion (36) defines with a center axis (A) of the hub (30) a distance gradually decreasing toward the outlet (34). Thus, the propeller has the advantages of reducing the drag and increasing the propulsive force of the boat when it rotates.