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
.17 Mach IV .17 Mach IV The .17 Mach IV is a wildcat centerfire rifle cartridge, based on the .221 Remington Fireball case, necked down to fire a .172 bullet. The cartridge was introduced in 1962 by Vern O’Brien. The cartridge offered an easy case conversion and good ballistics, but could not compete against the .17 Remington. The name, Mach IV, comes from the claim that the bullets can reach 4,000 ft/s. Due to the relatively small case capacity, even small variations in powder of can lead to the difference between a safe and dangerously over pressure load. The .17 Mach IV became