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Midnight Sun's MSX was designed with a steel space frame, whereas MSXI was designed using a carbon fibre monocoque.

Manufacturing

Creating composite panels for the body shell of a solar car requires molds to be made, which have historically started from CNC'ed polystyrene or medium density fibreboard (MDF). Flat panels do not require molds and can be made using a mirror. Composite panels can be made of fibreglass or carbon fibre, the latter of which has seen the most use by our team in MSXI. Structural panels that need high strength are usually made by sandwiching a core material, which can be a honeycomb or foam material, between layers of carbon fibre.

The manufacturing process of composite panels is usually referred to as a "layup". A "wet" layup involves laying sheets of carbon fibre or fibreglass onto a surface, applying epoxy resin,  and curing the soaked composite under a vacuum seal. This process is known as "vacuum bagging", because the film used to seal the vacuum is pressed against the panel by the ambient air pressure. A more advanced process involved using carbon fibre which has already been "impregnated" with resin, called "prepreg", which must be stored in a freezer to prevent the resin from curing before use. Once the material is removed it must be applied within a certain time and cured in an industrial oven or autoclave (pressure chamber).

Solar Car Powertrains

A vehicle's powertrain encompasses everything that generates power and propels the car by transferring it to the wheels. In a traditional gasoline automobile, this means the engine, gearbox, drive shaft (if present), differential, axles, suspension, and wheels. Solar cars, as electric vehicles, forego the engine, gearbox, drive shaft, and differential, since most solar cars use electric motors that directly mount behind the wheels. However, solar cars must have a large battery for energy storage and, of course, a PV array for energy generation.

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All ECU boards are designed and manufactured by the electrical team, which also contains a large software group dedicated to writing the embedded firmware for all ECUs. Midnight Sun has a relationship with a high-quality PCB fab located in Markham, but also uses various other fabs with faster lead time. All soldering is done by team members, which requires good training to ensure reliable solder joints are made consistently on our boards (debugging hardware manufacturing problems later takes far longer than getting it right the first time).