Derive the equations of motion for an airplane in descending gliding
flight (T=0) in a vertical plane. First, draw a free body diagram
showing an aircraft in gliding flight and all the coordinate systems,
angles, and forces. Here, assume that the velocity vector is at an
angle φ below the horizon and that the aircraft is at a positive angle
of attack α. Show that these equations have one mathematical
degree of freedom and are the same as those obtained from Eqs.
(2.24) with T = 0 and γ = −φ