Mach number a small area around the object's leading edge. (Fig.1b) Fig. 1. "Mach number in transonic airflow around an airfoil; M < 1 (a) and M > 1 (b)." When an aircraft exceeds Mach 1 (i.e. the sound barrier), a large pressure difference is created just in front of the aircraft. This abrupt pressure difference, called a shock wave, spreads backward and outward from the aircraft in a cone shape (a so-called Mach cone). It is this shock wave that causes the sonic boom heard as a fast moving aircraft travels overhead. A person inside the aircraft will not hear this.
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