ASC 6: Those freaky car shapes

The American Solar Challenge’s Challenger class is a race for single-person solar vehicles, powered by 4 square metres of silicon solar cells (or 2.64 m2 of multi-junction cells). There are three basic shapes for modern Challenger-class cars:

Symmetric cars

Symmetric cars are the most traditional, and the easiest to build. The disadvantage of symmetric cars is that there are three obstacles to airflow – the driver compartment and the left & right wheel fairings. This rear view of Illini’s Argo shows that quite clearly:

Illini’s Argo test-driving on the road (picture credit)

Asymmetric cars

Asymmetric or “catamaran” cars first showed up at the 2013 World Solar Challenge. They have only two obstacles to airflow, because the driver compartment is integrated into either the left or the right wheel fairing. This makes them faster, but substantially more difficult to build. At ASC 2016, only Michigan and Toronto (both fresh from WSC 2015) had asymmetric cars. This year, there are several.

Should asymmetric cars have the driver on the left or on the right? There are arguments both ways. The American Solar Challenge this year runs east to west, so the sun is mostly on the left side of the car (and rising no higher than about 70° in the sky). Therefore cars with the driver on the right (everybody except ETS Quebec) have a slight advantage. On the other hand, seating the driver on the left gives a better view of the road (in the US, at least).

MIT’s Flux test-driving on the road (picture credit)

“Bullet cars”

Last year’s World Solar Challenge saw the introduction of long, narrow “bullet cars,” which were made possible by the reduction in allowable solar cell area. Michigan came 2nd and Tokai 4th in cars like that. Michigan’s Novum is definitely the favourite to win the American Solar Challenge this year. But of course, anything can happen!

Michigan’s Novum coming 2nd at the 2017 World Solar Challenge (picture credit)