Critical Mach number and slow down as it travels around the aircraft's structure. When the aircraft's airspeed reaches the critical Mach number, the speed of the airflow in some areas near the airframe reaches the speed of sound, even though the aircraft itself has an airspeed lower than Mach 1.0. This creates a weak shock wave. As the aircraft exceeds the critical Mach number, its drag coefficient increases suddenly, causing dramatically increased drag, and, in an aircraft not designed for transonic or supersonic speeds, changes to the airflow over the flight control surfaces lead to deterioration in control of the aircraft. In aircraft
Mach Five "Mach 6", two different single-seater cars created specifically for stunt races. The designs of the Mach 4 and Mach 6 are vaguely reminiscent of the Mach Five's (as in the original American comics), although the only functions the Mach 6 features are the jump jacks, which are standard equipment in race cars in the movie. Little about the Mach 4 is known, as it appears only briefly in the film and is portrayed as a red-colored companion to the 6. The film portrays the Mach Five as initially being a regular everyday vehicle, justifying the existence of its trunk door