Critical Mach number Critical Mach number In aerodynamics, the critical Mach number (Mcr or M* ) of an aircraft is the lowest Mach number at which the airflow over some point of the aircraft reaches the speed of sound, but does not exceed it. At the lower critical Mach number, airflow around the entire aircraft is subsonic. At the upper critical Mach number, airflow around the entire aircraft is supersonic. For an aircraft in flight, the speed of the airflow around the aircraft differs considerably in places from the airspeed of the aircraft; this is due to the airflow having to speed up
Ford Mustang Mach 1 than six factory performance Mustang models were available (GT, Boss 302, Boss 429, Shelby GT350, Shelby GT500 and the Mach 1). Additionally, seven variations of V-8s were available in the '69–'70 models; most of these also available in the new Mach 1. Due to the Mach 1's success, the GT model was discontinued after 1969 following poor sales of 5,396 units versus the 72,458 sales for the Mach 1. The Mustang would not wear the "GT" badge again until 1982. The Mach 1 package was only available in the 'SportsRoof' body style (previously known as the 'Fastback'); never on the