Stealth aircraft Earlier stealth aircraft (such as the F-117 and B-2) lack afterburners, because the hot exhaust would increase their infrared footprint, and flying faster than the speed of sound would produce an obvious sonic boom, as well as surface heating of the aircraft skin which also increases the infrared footprint. As a result, their performance in air combat maneuvering required in a dogfight would never match that of a dedicated fighter aircraft. This was unimportant in the case of these two aircraft since both were designed to be bombers. More recent design techniques allow for stealthy designs such as the F-22
Sonic boom other's way quickly enough. Eventually they merge into a single shock wave, which travels at the speed of sound, a critical speed known as "Mach 1", and is approximately at sea level and . In smooth flight, the shock wave starts at the nose of the aircraft and ends at the tail. Because the different radial directions around the aircraft's direction of travel are equivalent (given the "smooth flight" condition), the shock wave forms a "Mach cone", similar to a vapour cone, with the aircraft at its tip. The half-angle between direction of flight and the shock wave formula_1 is