Final answer:
The Supercritical airfoil is the most effective in delaying the formation of shockwaves, contributing to enhanced aerodynamic efficiency and lower drag in high-speed applications, such as in racing cars and bobsleds.
Step-by-step explanation:
The best airfoil section for delaying the onset of a shockwave is the Supercritical airfoil. Unlike the Symmetrical, NACA (which represents a series of airfoil shapes), and Cambered airfoil designs, supercritical airfoils are specifically designed to delay the formation of shock waves at high subsonic speeds, which is crucial for improving aerodynamic efficiency and reducing drag. In the context of bobsled racers and racing cars, as mentioned in the reference, the shaping of these vehicles also aims to minimize drag by adopting aerodynamic shapes like that of a bullet with tapered fins.
The value of the drag coefficient, C, is an empirical measure that is crucial for understanding the aerodynamics of an object. This value is often determined with the use of wind tunnel testing, which provides essential data for the design and optimization of vehicles and airfoils in terms of aerodynamic performance.