Mach tuck significant in causing a tendency to dive, delta-winged aircraft with no foreplane or tailplane in the first case and, for example, the Lockheed P-38 in the second case. Alternatively, a particular design may have no significant tendency, for example the Fokker F28 Fellowship. As an aerofoil generating lift moves through the air, the air flowing over the top surface accelerates to a higher local speed than the air flowing over the bottom surface. When the aircraft speed reaches its critical Mach number the accelerated airflow locally reaches the speed of sound and creates a small shock wave, even though the
Mach tuck provide a larger stabilizing pitch-up moment. The camber and thickness of the aerofoil affect the critical Mach number, with a more highly curved upper surface causing a lower critical Mach number. On a swept wing the shock wave typically forms first at the wing root, especially if it is more cambered than the wing tip. As speed increases, the shock wave and associated lift extend outwards and, because the wing is swept, backwards. The changing airflow over the wing can reduce the downwash over a conventional tailplane, promoting a stronger nose-down pitching moment. Another problem with a separate horizontal stabiliser