Aircraft, flight control device and method for determining maneuvering reserve in aircraft

A method for determining a maneuvering reserve in an aircraft having a number of propulsion units, preferably a multirotor VTOL aircraft, most preferably an aircraft with electrically operated drive units for the rotors, includes the steps: determining a control vector [tau]=(L M N F)T for the aircraft, the components of which control vector represent a control torque L of the aircraft around a roll axis, a control torque M of the aircraft around a pitch axis, M, and a control torque N of the aircraft around a yaw axis, and a total thrust F; approximating an existing four-dimensional control space of the aircraft by a four-dimensional ellipsoid, the axes of which represent the control torques, L, M, N, of the aircraft and the total thrust, F; determining a normalized control vector, [tau]ind=(Lind Mind Nind Find)T, for the aircraft, using axis dimensions of the ellipsoid, in particular semi-axis dimensions of the ellipsoid; and outputting at least the normalized control vector [tau]ind, for determining a perm