ELECTRIC PROPULSION SYSTEM

HIGH FLYING DRONES PROPELLED BY FIXED SPEED FANS HAVE BEEN SUCCESSFULLY FLOWN BEFORE. THE FIXED SPEED IS DICTATED BY THE CHARACTERISTICS OF THE TURBINE PRIME DRIVER WHICH DELIVERS HIGHEST EFFICIENCY AT A PARTICULAR SPEED. THE FIXED SPEED CONSTRAINT COMPROMISES THE FAN PERFORMANCE CONSIDERABLY, EVEN WITH VARIABLE PITCH BLADES. AN APPROPRIATE ELECTRIC DRIVE CAN CONVERT THE FIXED SPEED POWER OUTPUT OF THE TURBINE TO A VARIABLE SPEED OUTPUT AT THE FAN. THE MOTOR ADDS MASS AND IMPOSES AN ADDITIONAL ENERGY LOSS IN THE "DRIVE TRAIN" BUT ALLOWS OPTIMAL DRIVE PERFORMANCE OVER THE ENTIRE ALTITUDE RANGE. THIS IN TURN LEADS TO LOWER FUEL REQUIREMENTS AND A LONGER FLIGHT RANGE AND/OR DURATION OF THE UAV. HOWEVER, A LIGHT-WEIGHT, EFFICIENT DRIVE MOTOR IS CRUCIAL FOR A SUCCESSFUL TRADEOFF BETWEEN ADDED MASS AND INCREASED EFFICIENCY. THIS PROPOSAL DESCRIBES TWO INNOVATIVE COMPACT MOTOR DESIGNS WHICH PROVIDE THESE CHARACTERISTICS. IN THE PHASE I PROGRAM, THE PROJECT TEAM, CONSISTING OF EXPERTS IN HIGH ALTITUDE FAN DRIVEN VEHICLES AND VARIABLE SPEED MOTOR DRIVES, WILL DESIGN A VARIABLE SPEED MOTOR WHICH, TOGETHER WITH A VARIABLE PITCH FAN, WILL DELIVER EFFICIENT THRUST POWER OVER THE WHOLE ALTITUDE RANGE. A PROTOTYPE WILL BE BUILT AND TESTED IN A PHASE II PROGRAM. ANTICIPATED BENEFITS/POTENTIAL APPLICATIONS - THIS RESEARCH WILL IMPROVE THE PERFORMANCE OF MILITARY UNMANNED AIR VEHICLES BY DEVELOPING A SCALABLE, COMPACT, AND QUIET ELECTRIC PROPULSION SYSTEM. POTENTIAL COMMERCIAL APPLICATIONS INCLUDE IMPROVED ELECTRIC MOTORS AND CONVERTERS FOR COMMERCIAL AND MILITARY VEHICLES.