Taking the main propulsion direct drive permanent magnet motor (PMM) of all-electric unmanned aerial vehicle (UAV) as the object of study

the heat load characteristics of main propulsion motor were analyzed in different working conditions. The fluid-solid coupled physical and mathematical models were established under strong cooling condition for the structure characteristics of open of main propulsion motor according to the fluid mechanics and heat transfer theory. The temperature rise of main propulsion motor was calculated in different heat loads and climbing angles. The changing rules of heat load and temperature rise of main propulsion motor were deeply analyzed under different working conditions. The wind tunnel and flight tests of main propulsion motor were performed. Result shows that

the highest temperature rise of motor is 124K when the heat load is 5500A2/(cm·mm2). Compared with the simulation value

the accuracy is within 2%

verifying the correctness of theoretical analysis. The heat load range of UAV main propulsion motor is between 3000A2/(cm·mm2) and 5500A2/(cm·mm2).