Date of Award

Spring 2021

Document Type

Thesis

Publisher

Santa Clara : Santa Clara University, 2021.

Department

Mechanical Engineering

First Advisor

Godfrey Mungal

Abstract

The electric hydrofoil community has become very popular in recent years with its two major subsections being divided up into those that buy their boards commercially and those that build their own (the DIY community). The commercial boards are extremely expensive and can reach prices of over $12,000. This is the root cause of the rapidly growing DIY community who can build functioning boards for around $3000. Reducing this entry cost has made the sport much more accessible to new members and has allowed both the size of the community and awareness of the sport to increase. For this report the DIY community was analyzed for weak points and major issues or hurdles that they may face. This exposed major safety concerns, and R&D issues as the community lacked the resources and knowledge to solve since each DIY board is a unique build with unique issues. Often, E-Foil boards are built in the fastest manner possible with the cheapest components, adhering to the strict goal of creating an operational device. This creates large gaps in safety for these DIY builds often ignored in favor of speed, battery life, or pricing. Examples of this negligence are, sub-par battery waterproofing, implementing propellers with no duct leaving an exposed blade spinning at several thousand RPM, and potentially utilizing materials that can be dangerous or un-optimized for water sport use. Using Solidworks fluid flow simulations, a duct and propeller system was created that was able to retain 94% of the efficiency of a ductless system while boasting a 30% increase over the open-source duct and propeller used by the community. This explains why the open-source duct is often removed since riders would be experiencing only about 60%-65% of the efficiency as they would without it. To confirm a proof of concept, the designs generated through the duct optimization iteration process were then live tested in water. The results showed that a bad duct design can be dramatically more inefficient creating a device that no longer functions in the water or it can be so efficient that the difference between ducted and un-ducted propeller setups have nearly no noticeable change to the rider’s experience. This report outlines these issues in greater detail, explain how they were solved or mitigated, with the importance of making the findings reproduceable within the community. Further recommendations include iterating on the propeller design to find the optimal E-foil propeller, while referencing back to the duct to ensure the new prop does not require another redesigned duct. This could be iterated any number of times in searching for the best duct-propeller combination.

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