Feasibility Analysis for a Microwave Deicer for Helicopter Rotor Blades.

摘要

An analysis of the feasibility of utilizing microwave energy to deice helicopter rotor blades is presented. The analysis is based upon the coupling of microwave energy to the ice layers by means of dielectric surface waveguides coating the leading edge of the rotor blades where the ice accumulates. The thickness of the dielectric coating is adjusted by design so that in the ice-free condition a loosely bound surface wave may propagate along the coating with only minor losses. As the ice accumulates, tending to thicken the surface waveguides, the surface wave, becoming more tightly bound, undergoes higher losses, dissipating much of its energy in the lossy ice layer. The dissipation of energy in the ice raises its temperature above the level required for breaking its bond to the blade, which occurs before any melting takes place. The analysis considers four major topics: (1) the properties of surface waveguides, including dielectrics suitable electrically and mechanically for rotor blades and the dielectric properties of rotor ice; (2) dissipation and heat distribution theory; (3) the problems associated with coupling microwave energy to the surface waveguides; and (4) the typical and preliminary configuration, and the cost of installing microwave deicers in UH-1 helicopters in production quantities. (Author)