Improved Propeller De-Icing Systems

The de-icing systems for propellers on Navy aircraft can be improved by using electrical sliding fiber contacts and an integrated electrical contact ring assembly. The electrical sliding contacts proposed will be fiber brushes rather than solid monolithiccontacts. These contacts have demonstrated the ability to carry large currents at high speed in contaminated environments of oil and dirt. The brush will be designed along with its holder to minimize losses, reduce wear, improve reliability and simplifymaintenance. The fiber diameter and length will be determined to meet design goals as well as selecting the fiber material itself and its fabrication process. The slip ring electrical contact assembly will be designed using filament winding techniquesto produce an integrated assembly capable of with standing expected temperature gradients, vibration and electrical heating without performance degradation of assembly failure. The best metal surface treatment of the slip rings will be determined tominimize wear and extend life. The feasibility of using an inductively coupled heater, which eliminates the sliding contracts, will be determined including its ability to meet Navy EMI requirements.The Phase I option program will fabricate a sample brush and holder designed in the base program to show feasibility. A sub scale slip ring assembly will also be constructed with one copper slip ring to demonstrate fabrication techniques. A testapparatus will be designed to simulate operating conditions for the complete de-icing systems in preparation for laboratory testing in Phase II. The proposed electrical sliding contacts and slip ring assembly will eliminate assembly failure by using advanced composite design and fabrication techniques. The use of fiber brushes will reduce wear and electrical losses while having the ability tofunction in adverse environments and oil contaminations. Maintenance will be a minimum with the expected time intervals of much more than 1000 hrs.