The powerplant has always played a vital role in the development of aviation. In the beginning, the crucial need was for an engine of high enough power-to-weight ratio to enable the aircraft to fly at all. The Wright brothers had to build their own, and they took to the air with a four cylinder petrol engine having a specific weight of around 15 lb/hp. Much progress was made over the next two decades, and by the mid-nineteen twenties this figure was down to about 2 lb/hp. The aeroplane was now emerging from its infancy; the Atlantic had been flown, and the Otto cycle engine had established itself as successfully in the air as on the road.

This paper is intended to supplement a part of the paper by Mr. F. W. Armstrong on ‘The aero engine and its prospects—fifty years after Griffith’. It deals in more detail with Dr. A. A. Griffith's early ideas on the aerodynamic aspects of turbomachines.

Even with reasonably optimistic use of materials and operating temperatures it was essential in 1926 that very high component efficiencies were obtained to make the gas turbine competitive with the piston engine on fuel consumption. Griffith believed that efficiencies of over 90% could be obtained for the compressor and turbine components, if the correct attention was given to the aerodynamic design of the blades. His 1926 report on ‘An aerodynamic theory of turbine design’ showed how such high efficiency designs should be carried out and gave appropriate formulae for the compressor and turbine efficiencies.

The small deflection/initial buckling behaviour of elastic, homogeneous plates is characterised by the absence of coupling between in-plane and out-of-plane quantities, i.e. stress couples, shear strains etc. By contrast, heterogeneous plates, of which generally laminated plates are an example, exhibit ‘shell-type’ behaviour in as much as in-plane and out-of-plane quantities are coupled. Reissner and Stavsky were the first to correctly formulate the field equations for such plates. Since that time a large number of papers on the influence of coupling on the behaviour of many different types of laminated structural elements, such as beams, plates and shells have appeared in the literature. However, it appears that until quite recently, the analysis of these structural elements in the presence of a general (Winkler/Pasternak) elastic foundation has not been undertaken.