pub fn rail_button_drag_coefficient(mach: f64) -> Result<f64, AeroError>Expand description
Parasitic drag coefficient of a rail button on its frontal area (the side profile of its base,
waist and flange): Niskanen’s rail-pin rule (2009 p. 52), a pin drags like a solid launch lug
as long as its diameter, (C_D•)_stag (Hoerner p. 5-8 gives 0.80 for a pin on a wall).