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This drag function was known as the Gavre function and the standard projectile adopted was the Type 1 projectile. Thereafter, the Type 1 standard projectile was renamed by Ballistics Section of Aberdeen Proving Grounds in Maryland, USA as G 1 after the Commission d'Experience de Gâvre.
Most ballistic tables or software takes for granted that one specific drag function correctly describes the drag and hence the flight characteristics of a bullet related to its ballistics coefficient. Those models do not differentiate between wadcutter, flat-based, spitzer, boat-tail, very-low-drag, etc. bullet types or shapes. They assume one ...
Drag coefficients in fluids with Reynolds number approximately 10 4 [1] [2] Shapes are depicted with the same projected frontal area. In fluid dynamics, the drag coefficient (commonly denoted as: , or ) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water.
A ballistic body is a free-moving body with momentum, which can be subject to forces such as those exerted by pressurized gases from a gun barrel or a propelling nozzle, normal force by rifling, and gravity and air drag during flight.
Drag and lift coefficients for the NACA 63 3 618 airfoil. Full curves are lift, dashed drag; red curves have R e = 3·10 6, blue 9·10 6. Coefficients of lift and drag against angle of attack. Curve showing induced drag, parasitic drag and total drag as a function of airspeed. Drag curve for the NACA 63 3 618 airfoil, colour-coded as opposite plot.
drag force F d. Using the algorithm of the Buckingham π theorem, these five variables can be reduced to two dimensionless groups: drag coefficient c d and; Reynolds number Re. That this is so becomes apparent when the drag force F d is expressed as part of a function of the other variables in the problem:
Most VLD bullets are used in rifles. VLD bullets typically have a ballistic coefficient greater than 0.5, although the threshold is undefined. [1] Bullets with a lower drag coefficient decelerate less rapidly. A low drag coefficient flattens the projectile's trajectory and also markedly decreases the lateral drift caused by crosswinds. The ...
This increase can cause the drag coefficient to rise to more than ten times its low-speed value. The value of the drag-divergence Mach number is typically greater than 0.6; therefore it is a transonic effect. The drag-divergence Mach number is usually close to, and always greater than, the critical Mach number.