pub fn conical_boattail_chart(x: f64, area_ratio: f64) -> Result<f64, AeroError>Expand description
MIL-HDBK-762 Fig. 5-122’s y = 4 C_D (l/d₁)² for a conical boattail of area ratio
a = (d₂/d₁)² at x = √(M² − 1)/(2 l/d₁) from 0 to 1.4 (CHART_Y): log-log in x between
the readings, held below x = 0.06, and linear in a between the curves. Past the chart’s
last curve, a > 0.8, it goes to 0 at a = 1 as (1 − √a)² (linear theory’s pressure is
proportional to the surface slope, so at a fixed length the drag goes as the slope squared);
below its first, a < 0.25, it continues the straight line through the 0.25 and 0.30 curves.
§Errors
AeroError::Domain for x outside [0, 1.4] or a outside [0, 1].