Question
What is the MOST energy efficient/aerodynamic basic car body shape of a US street legal 4 passenger car that can be built? We want to build a record breaking vehicle for the NESEA (www.nesea.org) Tour de Sol. (Example: MIT built the Aztec 2 passenger car based on a Morelli design which was calculated to perform at more than 300 miles per gallon equivalent in the 1990's.) P.S. According to TdS rules a simple torpedo with everyone laying down in a line is unacceptable. It must have side by side passenger seating and driver eye level must be a certain height above above the seat.
Thanks.
Mike
Answer
The most aerodynamically-efficient shape (one that minimizes drag) would be similar to a wing, rather than a torpedo. This shape would be rounded in the front and tapered in the rear. A flying wing, similar to the B-1 bomber, has been shown to be more aerodynamically-efficient than a conventional airplane with a torpedo-like fuselage. Unfortunately, this would not be a very practical shape for a car requiring that a driver and passenger sit side-by-side. Maybe the contest rules would allow two vertical wing-shaped cockpits (one for the driver and one for the passenger) joined together by a thin horizontal wing-like strut! Seen from the front, the car would be in the shape of the letter H.
The other way to minimizing drag is to break up air vortices along the surface of the object. Lately, scientists who study whales have noted that the leading edges of the whales' flippers have "knobs" on them, with the trailing edges being scalloped (wavey) instead of straight like an airplane wing. The scientists have discovered that these knobs and scalloped edges reduce drag by breaking up water vortices.
Incorporating these design features might make the car resemble a very unusual-looking whale!
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