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 1 models of the previous four years. The 302 Windsor returned in 1975, rated at and of torque, giving the Pinto platform a notable performance boost. Also available was a 4-speed manual. The Mach 1 remained mostly unchanged in 1976, as a new performance model - the Cobra II - was introduced alongside. 1977 proved to be the weakest sales year of the Mach 1 to date, selling only 6,719 units. The nameplate remained for one more year, upon when it was discontinued with the advent of the third generation Mustang in 1979. During the 1990s, the preeminent performance Mustang