What is the Difference Between Supersonic and Hypersonic?

In aerodynamics, the supersonic (hypersonic) speed refers to a rather high supersonic speed. In the 1970s, the word usually referred to Mach 5 (5 times the speed of sound) or higher. The supersonic flow regime is a branch of the supersonic flow regime.

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In aerodynamics, the supersonic (hypersonic) speed refers to a rather high supersonic speed. In the 1970s, the word usually referred to Mach 5 (5 times the speed of sound) or higher. The supersonic flow regime is a branch of the supersonic flow regime.

Supersonic airflow is very different from subsonic airflow. When an aircraft accelerates to supersonic speed, almost all air characteristics in the path change drastically. But despite such clear lines, there are still some disputes over the definition of "supersonic". One definition is that the speed of all parts of the entire aircraft is at or above Mach 1. A more technical definition states that all airflow velocities around the entire aircraft must be supersonic in order to be called supersonic. This is usually the case for aircraft of ordinary design, around Mach 1.2. The range of Mach 0.8 to 1.2 is therefore called transonic.

Considering that even the simple definition of supersonic speed is controversial, you won't be surprised that "defining supersonic speed is more difficult", because there is no change in the physical properties of airflow to become supersonic . In general, around Mach 5, some combination of effects becomes important overall. Supersonic flow regime is often defined as the speed at which a ramjet cannot produce net thrust. This is a vague definition, because there are some proposals for modification to make jet engines still operable in this speed range.