LOW COST ANGLE-OF-ATTACK SENSOR FOR SUBSONIC AIRCRAFT

THE OBJECTIVE OF THIS PROJECT IS TO DEVELOP A LOW COST SMARTANGLE OF ATTACK AND ANGLE OF SIDESLIP SENSOR (SAASS) THAT RESOLVES AERODYNAMIC FLOW FORCES EXERTED ON A SPHERE ELEMENTINTO COMPONENTS OF MAGNITUDE AND DIRECTION. THIS CONCEPT UTILIZES A UNIQUE 3-AXIS FORCE TRANSDUCER DESIGNED TO BE RUGGED, SENSITIVE, AND MOTIONLESS. THE PROPOSED DESIGN HAS A FIXED-POSITION SENSING ELEMENT CAPABLE OF MEASURING VELOCITY HEADING AND FLOW DIRECTION OVER A COMPLETE 360-DEGREE ANGLE. THIS WILL PRODUCE A 3-AXIS VELOCITY VECTOR THAT WILL ENABLE THE DETERMINATION OF ANGLE-OF-ATTACKAND ANGLE-OF-SIDESLIP. BY INCORPORATING A MICROPROCESSOR INTO THE SAASS, IT WILL BE POSSIBLE TO DIGITALLY COMPENSATE FOR AIRFLOW TEMPERATURE AND PRESSURE TO CALCULATE ABSOLUTE VELOCITY. A PROTOTYPE AIRFLOW SENSOR WITH A SENSITIVITY OF 1 DEGREE WILL BE DESIGNED, FABRICATED, AND TESTED DURING THE PHASE I EFFORT. BY COMBINING A SIMPLE MECHANICAL DESIGNWITH LOW COST CMOS VLSI CIRCUITRY, A PROBE CAN BE DEVELOPED AT A COST OF APPROXIMATELY $200/UNIT. THE PROBE, SOFTWARE, AND SERIAL INTERFACE WILL BE DELIVERED TO NASA AT PHASE I COMPLETION FOR DEMONSTRATION ON A STANDARD IBM PC.