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
Mach 1: A Story of Planet Ionus Mach 1: A Story of Planet Ionus Mach 1: A Story of Planet Ionus is a 1957 science fiction novel by Allen A. Adler. A paperback version was published in 1966 by Paperback Library with the alternate title Terror on Planet Ionus. While testing an experimental warship, the "Mach 1", a human pilot and his companion are kidnapped into space by aliens from the planet Ionus, which turns out to be a moon of Saturn. There, they confront an oversized monster named Karkong who is menacing the Ionians. Karkong follows them back to Earth. Chaos ensues. Damon Knight wrote of