A High Efficiency Electric Motor Propeller Propulsion System for Solar Powered UAVs

The design of very long duration (many days/months) unmanned air vehicles (UAV's) powered by solar electric systems has been shown to be feasible. However, the air vehicle propulsion system must be extremely efficient for the system to fly year-round at mid to high latitudes carrying positive payloads. The designs of lightweight electric motor-propeller propulsion systems that meet this need are presented. The designs have total propulsion efficiencies of over 80 percent, and weigh less than 10 pounds (motor + propeller). The propeller designs produce efficiencies of over 85 percent, and weigh less than 5 pounds. The electrical motor designs produce up to 3Kw of peak continuous power at efficiencies of near 90 percent, and continuous cruise power of up to 1Kw at efficiencies near 95 percent, and weigh less than 5 pounds