Extended Implications of Racecar Ground-Effect Machines

Racecars are the most widely-used ground effect machines, demonstrating the value of technologies like skirts (fences) operating at low clearances to the road. This paper compares the computational fluid dynamics of digital race car digital prototypes to ground effect flight transit (GEFT) vehicle digital prototypes. Whereas conventional explanations such as the “Venturi effect” fail to explain the pressure profiles, the computational fluid dynamics results are explained by three basic principles of physics, where: 1) impacting air creates higher pressures, 2) diverging air creates lower pressures, and 3) pressure expands at the speed of sound. These three basic principles of physics explain how moving a racecar’s rear spoiler to the front of the vehicle transforms the aerodynamics from suction forces on the racecar’s underbody to lift forces on GEFT’s underbody. The pressure profiles are verified by decades of racecar performances, including car stability and road-morphology-induced flight. The GEFT applications enable vehicle designs with substantially reduced rolling losses which result in half the per-passenger-mile energy consumption of the best alternatives.