UAV PASSIVE PROPELLER LOAD CONTROL

THERE IS A NEED TO IMPROVE THE EFFICIENCY OF PROPELLERS FOR EXISTING AND FUTURE UAV SYSTEMS. PROPELLER PITCH CONTROL PROVIDES A VERY EFFECTIVE MEANS OF ACHIEVING GOOD PERFORMANCE OVER A WIDE RANGE OF FLIGHT CONDITIONS AND IS THE METHOD UTILIZED BY CONVENTIONAL ACTIVE SYSTEMS. FOR LIGHTWEIGHT UAV APPLICATIONS, SEMI-AUTOMATIC OR PASSIVE SYSTEMS ARE POSSIBLE AND VERY BENEFICIAL. THE ADVANTAGES OF A PASSIVE SYSTEM ARE IN ITS POTENTIAL FOR INCREASING THE PERFORMANCE OF UAVS WITH MINIMUM IMPACT ON EXISTING PROPULSION SYSTEMS FOR LESS WEIGHT AND COMPLEXITY THAN CONVENTIONAL COMMERCIAL AND MILITARY. A SIMPLE AND EFFECTIVE PASSIVE PITCH CONTROL USING A BEAM-TORQUE MEMBER MOUNTED WITHIN THE BLADE STRUCTURE AND ATTACHED TO THE BLADE AT A STATION AT ABOUT HALF THE PROPELLER RADIUS IS DESCRIBED. THIS STRUCTURAL PROCEDURE IS NOT POSSIBLE ON CONVENTIONAL AIRCRAFT PROPELLERS, BUT THE SMALLER SCALE AND POWER OUTPUT OF THE UAV MAKE IT ACCEPTABLE IN THIS CASE. A FOUR TASK PROJECT IS DESCRIBED INVOLVING DESIGN REQUIREMENTS IN TASK 1, DEVELOPING A COMPUTER DESIGN METHOD FOR THE BLADE PITCH DYNAMICS IN TASK 2, EXERCISING THE METHOD IN TASK 3 TO DESIGN A SPECIFIC PASSIVE PITCH PROPELLER, THEN EVALUATE AND DOCUMENT IN TASK 4.