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
Ford Mustang Mach 1 5800 rpm (4-speed automatic)." While on paper the 305 hp (228 kW) ratings seem a loss when compared to the 1999 and 2001 SVT Cobras which produced 320 hp (239 kW), in practice the Mach 1 engine produced similar peak horsepower and substantially more torque. Further differences included the use of Ford's solid rear axle with a 3.55 final ratio (As opposed to SVT's Independent Rear Suspension) also the availability of a 4 speed automatic in addition to the Tremec sourced 5 speed manual. Factory steel "Box" cross section subframe connectors were also added to increase chassis strength for both