pub const CD_TO_RETARD: f64 = 2.08551e-4;Expand description
Cd-to-retardation conversion for ICAO-referenced BCs.
Exact imperial retardation form for density normalized to ICAO sea-level air (1.225 kg/m^3 / 0.076474 lb/ft^3):
a_ft/s^2 = Cd * v_fps^2 * (rho / 1.225) * CD_TO_RETARD / BC
The older 0.000683 * 0.30 value is the Army Standard Metro constant and is
only consistent with a 0.075126 lb/ft^3 density reference.