Magnesium composite material for advanced rotary aircraft engines

摘要

Rotary engines are attractive power sources for general aviation aircraft because of their potential for high efficiency and durability, which are a result of the low number of movable parts, compactness, and extremely high horsepower to weight ratio of these engines. In order to adapt the rotary engine to aircraft use, it is essential to reduce the weight of such components as the engine housings, rotors, and crankshaft. One method of reducing weight is to employ high performance, lightweight materials. Graphite/magnesium (Gr/Mg) composites, consisting of continuous graphite fibers in a magnesium alloy matrix, possess excellent mechanical properties combined with a very low density. In addition, these materials maintain both their integrity and their properties at the operating temperatures encountered in a rotary engine, plus they offer essentially metallic thermal conductivity. This Final Report summarizes the results of a Phase II SBIR program, sponsored by NASA Lewis Research Center, on the development of cast Gr/Mg rotary engine components. In Phase I, an intermediate housing was successfully cast; this component had been selected because it represented a major, but not impossible, casting challenge. For Phase II, the target component was changed to a rotor housing, because it was determined that the performance requirements of this housing would better demonstrate the advantageous properties of Gr/Mg castings. The ultimate goal of this program was the fabrication of a cast Gr/Mg rotor housing which would perform under the service conditions of an operating rotary engine.