The Aviation Engine

Abstract

This lecture is an attempt to give a cross-section of aviation engine development and progress during the last two decades. Such a lecture is now opportune, since great progress has been made during the last ten years—mainly due to the 1939–45 war and the advent of the aviation gas turbine. The rapid development of this prime-mover has started a new era in aviation and the well-tried piston engine is already being relegated to second place and even eliminated in the more important aircraft applications. The lecture is divided into two parts. The first deals with the piston engine and the second with the gas turbine. In the first part, the development of the piston engine is discussed; with emphasis upon those factors, such as supercharging and improved fuel, which have particularly contributed to its present high performance. Cooling developments of both the air- and the liquid-cooled engine are discussed, and also the influence of such detail refinements as the sodium-cooled valve and sparking plugs having sintered aluminium oxide insulators. The second part of the lecture describes the present forms of aviation gas turbine, with some details of its specific performance and the author's views concerning the future development and application of this new engine. At the request of the Council, and where relevant, the author has shown how the development of the aviation engine has influenced that of the automobile engine and he has also given—in Appendix I—a summary of his views on the application of the gas turbine to road-vehicle propulsion. This lecture would not be complete without reference to the great part played, in the 1939–45 war, by the aviation engine and automobile industries of Britain, in combining to produce large numbers of aviation engines for the Royal Air Force. In this particular connexion, the author is of the opinion that the experience and the production methods of the automobile industry, as a whole, contributed largely to the uniform excellence and economical production of the aviation engine, and fully vindicated the faith of those who originated the “Shadow” scheme in the rearmament period before the war.