This paper has been written at rather short notice, which has prevented me from going into statistics and detailed figures, as I would have wished. It is therefore given fairly broad brush treatment and concentrates mainly on the larger types of crop-spraying aircraft in the category of around 6/7000 lb all up weight. This is where the engine situation is most critical and the need for a satisfactory powerplant which the operator can afford is most needed.

My only claim to be able to offer ideas or suggestions and perhaps some prognostications for the future is by associating with a number of Ag operators over the last four years, mainly in the States and particularly at the last four National Agricultural Aircraft Conventions in Florida and at Las Vegas; I have therefore no intention of being pontifical. Another reason for caution is because most of my past experience with engine installations has been with sophisticated aircraft, such as jet fighters, where I have had the good fortune to be supported by a team of technical experts and colleagues.