A propulsion assembly for an unmanned aerial vehicle, UAV, said assembly comprising: a motor configured to rotate in a first direction (340, 650); a propeller seat (130, 212, 330, 610, 810) configured to be driven by the motor to rotate in the first direction (340, 650) and to receive a propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610); a sensor (240b,910); and one or more processors, i) wherein the sensor (240b,910) is configured to collect sensing data for determining i.1) when the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) is locked to the propeller seat (130, 212, 330, 610, 810), and i.2) when the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) is not locked to the propeller seat (130, 212, 330, 610, 810), without requiring operation of the motor; and the one or more processors are configured to obtain the sensing data from the sensor (240b,910) and to determine a spatial configuration between the propeller seat (130, 212, 330, 610, 810) and the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) based on the sensing data, or ii) wherein the sensor (240b,910) is configured to collect sensing data for determining whether the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) matches the propeller seat (130, 212, 330, 610, 810), without requiring operation of the motor; and the one or more processors are configured to obtain the sensing data from the sensor (240b,910). a motor configured to rotate in a first direction (340, 650); a propeller seat (130, 212, 330, 610, 810) configured to be driven by the motor to rotate in the first direction (340, 650) and to receive a propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610); a sensor (240b,910); and one or more processors, i) wherein the sensor (240b,910) is configured to collect sensing data for determining i.1) when the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) is locked to the propeller seat (130, 212, 330, 610, 810), and i.2) when the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) is not locked to the propeller seat (130, 212, 330, 610, 810), without requiring operation of the motor; and the one or more processors are configured to obtain the sensing data from the sensor (240b,910) and to determine a spatial configuration between the propeller seat (130, 212, 330, 610, 810) and the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) based on the sensing data, or ii) wherein the sensor (240b,910) is configured to collect sensing data for determining whether the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) matches the propeller seat (130, 212, 330, 610, 810), without requiring operation of the motor; and the one or more processors are configured to obtain the sensing data from the sensor (240b,910). i) wherein the sensor (240b,910) is configured to collect sensing data for determining i.1) when the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) is locked to the propeller seat (130, 212, 330, 610, 810), and i.2) when the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) is not locked to the propeller seat (130, 212, 330, 610, 810), without requiring operation of the motor; and the one or more processors are configured to obtain the sensing data from the sensor (240b,910) and to determine a spatial configuration between the propeller seat (130, 212, 330, 610, 810) and the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) based on the sensing data, or ii) wherein the sensor (240b,910) is configured to collect sensing data for determining whether the propeller (120, 210, 305, 640, 820a, 820b, 1250, 1510, 1610) matches the propeller seat (130, 212, 330, 610, 810), without requiring operation of the motor; and the one or more processors are configured to obtain the sensing data from the sensor (240b,910).