The B-58 Hustler was the first operational jet bomber capable of Mach 2 flight. The aircraft was designed and developed for the United States Air Force for service in the Strategic Air Command during the 1960s. It uses a delta wing with four General Electric J79 engines in pods under the wing. Replacing the B-47 Stratojet medium bomber, it was originally intended to fly at high altitudes and supersonic speeds to avoid Soviet fighters. The B-58 was notorious for its sonic boom, which was often heard by the public as it passed overhead in supersonic flight.