Improved Propeller De-Icing Systems

NAVAIR and NADEP have previously identified, through issuance of an SBIR N03-007 solicitation, that the Navy is seeking approaches that could remedy problems with the E-2C and C-2A propeller de-icing current transfer system. Presently, these systems are outfitted with monolithic carbon brushes that have a tendency to wear unevenly. Uneven brush wear and the large volume of brush wear debris produced results in the brushes mechanically sticking within the brush holder and fracturing while in service. Brush fracture then causes a loss of brush electrical contact with the contact ring and, left unchecked, can result in an electrical overload on the remaining brushes, ring overheating and finally, a Class “C” engine fire. Every 250 flight hours, preventative maintenance is conducted that includes: hub removal, system cleaning, re-brushing, hub reinstallation and system retesting. Noesis identified that metal fiber brush technology is a very promising approach to solving the propeller blade and spinner de-icing system current transfer problem for the E-2C and C-2A aircraft. Metal fiber brushes could be engineered as a direct substitution for existing problematic carbon brushes as a form-fit-improved function solution to the maintenance problem presently encountered with the propeller de-icing current transfer system.