Abstract: Improving convertible aircraft of the aforementioned type mainly in terms of the active control of vibrations, while at the same time avoiding the addition of significant additional masses for essentially countering the excitations caused by the rotors and, secondarily, of making such an aircraft easier to control in terms of roll in airplane mode. In this secondary objective, these improvements aim to allow simplifications to the maneuvering and command means for controlling the aircraft in terms of roll in airplane mode and preferably, at the same time, a simplification of the command and maneuvering means performing the functions of augmenting lift and reducing offsetting power. The invention also relates to improvements made to the convertible aircraft of the aforementioned type to give them the ability to land in airplane mode (without converting beforehand from airplane configuration to helicopter configuration).