TechnicalLearn about our design to win first place.
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The Goal
We, the 2019 Stevens Solar Splash team, have set our sights on an ambitious goal: winning the Solar Splash 2019 competition and becoming the international champions of intercollegiate solar/electric boating.
Hull
Our hull weighs in at approximately 55.3 lbs and is made from four lightweight layers: Duratec coating, an exterior coating of carbon fiber, Nomex Honeycomb, and an interior layer of carbon fiber. This lightweight hull our the competitive advantage and key to having a low overall system weight.
Stern Appendage
Our removable stern appendage bridges the gap between planing and displacement hull type. The stern appendage is attached during the endurance races to create a more traditional displacement type stern, which reduces drag compared with the transom stern used for the higher speed races.
Motor
Our motor consists of a DHX Hawk40 motor customized and rewound from 96V to 72V. This customization allowed the team to retain the high torque ratio while resulting in less of a power reduction when operating the motor using a 36V power bank.
Motor Controller
The InMotion 80L Motor Controller is programable and allows the team to adjust the factors such as the throttle values. The team can also look at the controller data to improve the system.
Steering
The steering system is composed of a drum steering wheel and a set of pulleys, donated by Portage Bay Systems, to transmit the directional controls from the skipper to the outboard. This type of system was selected because of its low weight and ease of installation and design for a unique outboard unit.
Outboard Design
The belt drive was chosen for the transmission over a gearbox due to its lower weight. When considering the gear ratios, the team accounted for the existing 16:21 gear ratio in the lower unit. The gear ratio created by the sprockets was designed to change the overall gear ratio of the drivetrain system to 1.32 for the sprint and 0.44 for the endurance based on the calculations performed. The belt drive that the team will use for the sprint race has a 71:41 ratio, or 1.73:1. The sprockets will then be reversed for the endurance race to yield a ratio of 1:1.73. These ratios were chosen based on the propeller RPM requirements and to simplify the system by making the sprockets reversible.