FUTURE engine developments for powers between 2000 and 4000 bhp and the author's views on the form which such engines will take, together with optimum cylinder sizes and number of cylinders, are covered in the latter part of Mr. Banks' paper. Because it concerns the possible future development of military aviation in America as well as his own Country, the author considers this part the important one.
In the first part, he gives a short résumé of the aviation fuel position in Great Britain, and then goes on to describe some work which he has done in conjunction with the British Air Ministry and one of the aero engine manufacturers on very high-duty aviation engines. He also discusses what, in his opinion, is a characteristic of the American two-valve hemispherical cylinder head relative to British four-valve engines in regard to fuel behavior. He continues, mentioning certain new developments, such as the treatment of poppet type exhaust valves with Brightray.
Views on the single-sleeve valve and, in detail, the latest information on the development of the sinterkorund (sintered aluminum oxide) spark plug, are presented. The subject of direct injection of gasoline also is dealt with.