Fig. 12. Diagram of the bumble attitude, horizontal speed and pitching rate, and the forces and moments during the first cycle of the disturbed motion (unstable oscillatory mode). u⁺, q⁺ and , disturbance quantities in non-dimensional x-component of velocity, pitching rate and pitch angle, respectively; M⁺, non-dimensional pitching moment; mg, insect weight; F₀, total aerodynamic force at equilibrium.