This paper describes the design and development of the HS. 748 short/medium range turboprop aircraft. At the RAeS Convention on “Economical Factors in Aviation” held on the 13th/14th May 1970, Mr. Knight of BAC stated, when analysing post-war British civil aircraft projects, that “there are really only three types that can be called true commercial aircraft successes. They are the Vickers Viscount, the HS.748 and the BAC One-Eleven”. This paper discusses the philosophy behind the original design of the aircraft, its development to date, its in-service history and also gives examples of the many different projects based on the HS.748 which have been and which are still being considered. The aircraft is described as the HS.748 throughout this lecture as this is its current designation. It should not be forgotten, however, that this aircraft was designed and flown as the Avro 748 for at least three years.

In 1972 civil sales formed some 30% of the US aerospace industry. Although in 1973 there was a swing back to defence products, civil sales retain an important position. Not surprisingly, aerospace industries without sizeable civil projects on hand, such as Britain's and Canada's, are looking with concern at their future prospects.

Such increasing dependence brings its own problems, for civil sales have been characterised by large fluctuations in the past. Predictions have often been wrong and costly, yet accuracy is a prerequisite of the industry's steady development. The heavy research and development and expenditure involved in a major civil programme necessitates a forecasting horizon of up to a decade.

I will put forward what I hope are reasonable explanations of why some of the more important features of the aircraft cockpit and the way in which an aircraft is controlled have been related to a particular side or direction of turning and circling; including the much debated origin of the left-hand circuit.

The ergonomists and the human factors researchers talk of the man/machine relationship and before getting down to detail cases we need to look closely at the human component of the man/machine interface in aviation. Relevant to the subject are the hand and side preferences of the human component, the pilot.

The first tandem-wing aircraft I saw appeared in an early 1960s edition of the boys comic—Lion. I dismissed it as a figment of the artist's imagination, but later came across the self-same aircraft in War Planes of World War 2—Fighters—Volume 2 by W. Green. From then on I have been collecting information on tandem-wing aircraft. Some eight years later what started as an interest in aircraft took an academic turn when I did a design study of a tandem-wing aircraft as part of an MSc.

When a rectangular beam is bent by two end moments about a transverse axis, it is well known that an “anti-clastic” curvature about a longitudinal axis also tends to occur. The theory for this phenomenon in isotropic beams has been previously discussed. For some recent work on the elastic properties of oriented silicon-iron transformer sheet, which is not only anisotropic but also has a non-linear stress-strain curve due to magnetic domain effects, a theory for anticlastic bending was necessary. The experimental results are reported elsewhere, but the theory used for anticlastic bending may find wider application. An expression is derived for the effective Young's modulus for a wide sheet; and its significance is demonstrated for transformer sheets of different width, ignoring the magnetic effects.