"Tuck-under" and "Tuck under" redirect here. For the practice of tucking male genitalia underneath the crotch to present a more feminine or androgynous appearance, see Tucking.
Mach tuck is an aerodynamic effect whereby the nose of an aircraft tends to pitch downward as the airflow around the wing reaches supersonic speeds. This diving tendency is also known as tuck under.[1] The aircraft will first experience this effect at significantly below Mach 1.[2]