Quadcopter power consumption analyzation at different landing trajectories

The power supply of quadcopters is provided for by a battery. Flight time depends on total weight and on battery capacity. The most widespread one is the lithium polymer (LiPo) battery. Its advantage is that it has a high electricity transmission ability and a very good mass-capacity ratio. In case of a critical capacity level it is important for the quadcopter to land as soon as possible. Landing speed however is limited. The so-called vortex wave state (vortex ring state) appears at landing. The vortex ring state was first observed at helicopters. The reason for the phenomenon is that at descent the air flow speed arriving from below at a vertical descent approximates the speed of the air currents generated by the rotors. In this moment, the air flowing through the rotors creates a closed vortex wave and a low-pressure spot is created. In this case, the perfomance of the rotors drops, the quadrocopter might become instable and uncontrollable. This phenomenon can be avoided by limiting descent speed. In the article, I tested how to increase descent speed to be able to land safely as fast as possible, using the least possible energy.