It may be stated definitely that installation as a whole has shown little progress as compared with the development of either the aircraft structure or engine, and that to-day the installation of the engine in a machine presents a wide field for sound engineering design and improvement. On the other hand, failure in some part of the installation is the most prolific cause of forced landings. Statistics taken over a considerable period have shown that of the proportion of forced landings resulting from engine stoppage, seven out of eight are due, not to any actual defect in the engine itself, but to some trivial breakdown in the installation.

Apart, too, from the question of reliability and safety, installation development provides room for considerable economy, not only as regards its actual upkeep and repair, but also from its effect on the easy (or otherwise) removal of the engine from the aircraft for overhaul and replacement purposes.

The subject on which I propose to address you to-night is certainly one with which this generation is not only rightly challenged, but one with which one could almost say that it should be taunted. For nowadays we pride ourselves on the fact that no great invention can be universally acknowledged to be successful without its being very rapidly turned to the economic service of mankind. But aviation has been a human accomplishment for more than half a generation, and so far no aeroplane has earned its cost and keep.

In the old days, when manufactures were primitive, when accurate machine tools did not exist, when very few people were interested or instructed in scientific things and no means existed for instructing or interesting the many, it was natural enough that great inventions should have been made and then allowed to expire, so to speak, without being used.