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 sought to revive the Mach 1 name. While similar to the Bullitt in the use of the Cobra's Brembo front brake rotors, unique Tokico gas shocks and struts, and lower and stiffer springs, the Mach 1 received a huge performance gain over the base GT and even the Bullitt in the form of a unique variant of the DOHC 32-valve 4.6 Liter Modular V8. Commonly known by Mach 1 owners as an "R" code DOHC, (for the unique VIN engine R code) this all-aluminium engine features the same high flow heads as the 2003–2004 SVT Cobra, 2003–2004 Mercury Marauder, 2003–2005