SHAPE MEMORY ALLOYS FOR USE IN ROTORCRAFT DEICING SYSTEMS

INCREASED READINESS AND SAFETY DEMANDS BEING MADE ON HELICOPTERS REQUIRE AN ALL-WEATHER CAPABILITY. WHILE SEVERAL PROMISING DE-ICERS HAVE BEEN DEVELOPED FOR FIXED WING AIRCRAFT, THE REQUIREMENT STILL EXISTS FOR A RELIABLE DE-ICING SYSTEM COMPATIBLE WITH HELICOPTER BLADES. THE IDEAL DE-ICER MUST BE SMALL, REQUIRE A MINIMUM AMOUNT OF INTERFACE HARDWARE, AND BE ABLE TO OPERATE EFFICIENTLY ON LOW POWER/VOLTAGE AND TO SURVIVE LEADING-EDGE-EROSION EFFECTS. THIS PROJECT WILL DEVELOP A UNIQUE ICE PROTECTION SYSTEM THAT IS BASED ON THE CAPABILITY OF SHAPE MEMORY ALLOYS (SMA) TO CHANGE DIMENSION RAPIDLY AND REVERSIBLY WHENCURRENT OR HEAT IS APPLIED. SEVERAL METHODS TO INDUCE THE SHAPE MEMORY EFFECT, INCLUDING INHERENT RESISTIVE HEATING OFTHE SMA OR HEAT TRANSFER FROM AN ATTACHED THERMAL COUPLE OR CONVENTIONAL ELECTROTHERMAL DE-ICING COIL WILL BE INVESTIGATED. MECHANICAL DEBOUNDING IS EXPECTED TO TAKE PLACE IN SECONDS VERSUS MINUTES USING ONLY A FRACTION OF THEPOWER REQUIRED FOR THERMAL DEBOUNDING. HELICOPTER BLADES MAY BE THE IDEAL APPLICATION FOR SHAPE MEMORY DE-ICERS BECAUSE OF THE SMALL LEADING-EDGE AREA AND AVAILABILITY OF CONVECTIVE COOLING TO INDUCE MARTENSITIC TRANSFORMATIONS. PHASE I INCLUDES DESIGN AND TEST OF A SMA HELICOPTER-BLADE DE-ICER PROTOTYPE FOR EVALUATION OF LEADING-EDGE ICE DEBONDING PERFORMANCE. INCREASED READINESS AND SAFETY DEMANDS BEING MADE ON HELICOPTERS REQUIRE AN ALL-WEATHER CAPABILITY. WHILE SEVERAL PROMISING DE-ICERS HAVE BEEN DEVELOPED FOR FIXED WING AIRCRAFT, THE REQUIREMENT STILL EXISTS FOR A RELIABLE DE-ICING SYSTEM COMPATIBLE WITH HELICOPTER BLADES. THE IDEAL DE-ICER MUST BE SMALL, REQUIRE A MINIMUM AMOUNT OF INTERFACE HARDWARE, AND BE ABLE TO OPERATE EFFICIENTLY ON LOW POWER/VOLTAGE AND TO SURVIVE LEADING-EDGE-EROSION EFFECTS. THIS PROJECT WILL DEVELOP A UNIQUE ICE PROTECTION SYSTEM THAT IS BASED ON THE CAPABILITY OF SHAPE MEMORY ALLOYS (SMA) TO CHANGE DIMENSION RAPIDLY AND REVERSIBLY WHENCURRENT OR HEAT IS APPLIED. SEVERAL METHODS TO INDUCE THE SHAPE MEMORY EFFECT, INCLUDING INHERENT RESISTIVE HEATING OFTHE SMA OR HEAT TRANSFER FROM AN ATTACHED THERMAL COUPLE OR CONVENTIONAL ELECTROTHERMAL DE-ICING COIL WILL BE INVESTIGATED. MECHANICAL DEBOUNDING IS EXPECTED TO TAKE PLACE IN SECONDS VERSUS MINUTES USING ONLY A FRACTION OF THEPOWER REQUIRED FOR THERMAL DEBOUNDING. HELICOPTER BLADES MAY BE THE IDEAL APPLICATION FOR SHAPE MEMORY DE-ICERS BECAUSE OF THE SMALL LEADING-EDGE AREA AND AVAILABILITY OF CONVECTIVE COOLING TO INDUCE MARTENSITIC TRANSFORMATIONS. PHASE I INCLUDES DESIGN AND TEST OF A SMA HELICOPTER-BLADE DE-ICER PROTOTYPE FOR EVALUATION OF LEADING-EDGE ICE DEBONDING PERFORMANCE.