Compound Engine Systems for Aircraft

An investigation of spark-ignition reciprocating engines indicates that considerable improvement in engine power and fuel consumption and in airplane range and payload can be achieved by compounding them with exhaust-gas turbines.

The improvement in performance increases with the degree of compounding and the attendant increase in complexity of the system.

The compression-ignition compound engines also appear to offer a possibility of appreciable gains over the spark-ignition systems; however, it is anticipated that a greater amount of development time will be required for the practical realization of the predicted performance of the compression-ignition system than of the spark-ignition engine.