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Bullet Drag Coefficient Formula:
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The bullet drag coefficient (Cd) is a dimensionless quantity that describes the drag or resistance of a bullet in motion through a fluid environment (typically air). It's a crucial parameter in ballistics for predicting trajectory, velocity decay, and energy retention.
The calculator uses the drag coefficient formula:
Where:
Explanation: The calculation accounts for the complex relationship between bullet velocity (expressed as Mach number) and the aerodynamic properties of the bullet shape.
Details: Accurate drag coefficient estimation is essential for ballistic trajectory prediction, long-range shooting accuracy, terminal performance analysis, and ammunition design optimization.
Tips: Enter Mach number (velocity/speed of sound), shape factor (typically between 0.5-1.5 for most bullets), and select the appropriate drag model. All values must be valid positive numbers.
Q1: What is Mach number?
A: Mach number is the ratio of an object's speed to the speed of sound in the surrounding medium. Mach 1 equals the speed of sound (~343 m/s in air at sea level).
Q2: What are typical drag coefficient values for bullets?
A: Most bullets have Cd values between 0.1 and 0.5, with modern low-drag designs achieving values below 0.2 at supersonic speeds.
Q3: How does shape affect drag coefficient?
A: Streamlined shapes (pointed nose, boat tail) reduce drag by minimizing air resistance and turbulence, while blunt shapes create more drag.
Q4: What's the difference between tabular and G1 models?
A: Tabular models use discrete data points while G1 uses a standardized mathematical function. G1 is more common for traditional bullet shapes.
Q5: Why does drag coefficient change with velocity?
A: Drag characteristics change significantly when transitioning between subsonic, transonic, and supersonic regimes due to shock wave formation and other aerodynamic effects.