What is the term used for the speed at which a shockwave forms on an aircraft?

The term used for the speed at which a shockwave forms on an aircraft is referred to as "Critical Mach." This is the specific speed at which airflow over some part of the aircraft reaches the speed of sound, leading to the formation of shockwaves, which can significantly impact the aircraft's performance and stability. When an aircraft exceeds this speed, it will experience changes in aerodynamics, including an increase in drag and potential control issues.

Understanding "Critical Mach" is essential because it helps pilots and engineers determine the operating limits of an aircraft, especially as speeds approach or exceed the speed of sound. Different aircraft will have varying Critical Mach numbers based on their design and intended operational envelope, affecting how they are flown at high speeds.

Other terms listed in the options, like "Critical altitude" and "Critical speed," relate to different aerodynamic concepts, but do not specifically denote the speed at which shockwaves occur. "Limit Mach" may refer to operational speed limits but is not a scientific term used in the same context as "Critical Mach."