Little has so far been written to specifically cover this subject*. Many papers and books make passing reference to it; many management courses touch lightly upon it. However, most writings and teachings on “salesmanship” deal with the conventional salesman with a detergent packet in hand, a foot in the door, and a “management objective” of umpteen calls per week. Nowhere have I found a reasoned analysis and exposition of the problems faced by those of our select band who try to sell high cost capital equipment, mostly in the export market.

Selling aero engines is unusual in that the aero engine is only an accessory to the aircraft —yet an accessory whose performance can often dictate the size and shape of the aircraft, as well as its profitability in operation. Nevertheless much of the techniques of selling this equipment is common to other prime movers and also reads across both to the aircraft manufacturer and to the smaller accessory supplier; many of the general principles apply across a wide field of capital goods.

A lecture called “Some aspects of buffeting” was given to the Society in 1961 by my colleague Mr. R. Fail. In that lecture the emphasis was primarily on the prediction of buffet onset in flight from model tests in wind tunnels, and on the prevention of buffeting. In the subsequent 11 years there has been much more interest in the prediction of the severity of buffeting above the buffet boundary, for both transport and fighter type aircraft, if buffeting cannot be prevented or alleviated. I have tried to reflect this interest and I hope that the title of this paper will also suggest a cautious examination of the physical processes at work above the buffet boundary, when the boundary layer has separated. We still really know very little about these processes but I hope that the paper may stimulate further research and questioning.