Constant FREEFORM_FIN_MARGIN_CAL 

pub const FREEFORM_FIN_MARGIN_CAL: f64 = 0.047;

The share of the static margin, calibres, that a kinked freeform fin’s center of pressure takes on OpenRocket’s Pods–airframes and winglets example, where hpr’s sits 1.6 mm aft of OpenRocket 24.12’s (issue #326). Unprobed on other outlines, so every freeform fin set warns.