Fig. 1: Inertial properties must be determined to quantify avian manoeuvrability.
From: Birds can transition between stable and unstable states via wing morphing
a, A bird’s centre of gravity (CG) is the position about which weight is equally distributed, and the neutral point (NP) is where aerodynamic forces can be modelled as point forces and the pitching moment is independent of angle of attack. The moment of inertia (I) components are obtained by integrating differential mass elements (dm) over the entire bird. b, Flight dynamics are affected by adjusting either inertial or aerodynamic characteristics. c–f, We modelled birds as a composite of simple geometric components. Each component’s centre of gravity varies as a wing morphs from an extended (c, d) to a folded (e, f) configuration. g, Convex hulls showcase the ROM of the elbow and wrist for 22 species. h, The computed maximum \({I}_{{{xx}}_{{\rm{wing}}}}\) was similar to published estimates. n = 36 individual specimens; 95% confidence intervals visualized by transparent ribbons.
