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 Lincoln Aviator, and the 2003–2009 Australian Boss 5.4 L V8s (see Ford of Australia Boss 5.4 L), the engine also has intake camshafts sourced from Lincoln's 5.4 Liter "InTech" V8 to provide more mid-range torque. The Mach 1 engine had a 10.1:1 compression ratio in contrast to the 1999 and 2001 Cobra's 9.85:1, and the Mach 1 was equipped with a Windsor Aluminum Plant or WAP block unique from the Teksid aluminium blocks used in the 1996–1999 Cobras. The Mach 1 also featured a relatively high redline of 6,800 rpm (5-speed cars) and fuel cut off at 7,050 rpm "or