For all who are specialists of one kind or another, it is a very healthy exercise to read books written by scientists or engineers of the calibre and breadth of F. W. Lanchester. He was at the same time truly a pioneer of flight, an expert in fluid mechanics, in flight mechanics, in the practical, and (well ahead of his time) in the military applications of flight, in the novel use of materials, and an inventor of devices and mechanisms. However, it was with particular surprise that I found, on studying the literature under the name F. W. Lanchester, a book published in 1935 entitled Relativity and two earlier papers on the subject published in 1921. Lanchester had met Minkowski in 1908 at the house of his friend Carl Runge, the applied mathematician, at Göttingen, and following a discussion with Minkowski had taken such an interest in the field that he was able to make these early English contributions.

Perhaps the most important property that makes such pioneers is the courage to think truly new thoughts. His fascination with the new philosophy in physics may be easily understood in terms of this bold style of thought.

An experimental correlation is presented between the losses and the inlet flow conditions in short dump diffusers for turbojet combustors. Cascades of compressor blades upstream of the diffuser were used to make the flow field at inlet similar to that in a real jet engine. The flow field was altered in two ways — by varying the distance between the cascades and the diffuser inlet plane and by changing the blade aspect ratio. The measurements show clearly that distortions in the radial direction affect the losses to a much larger extent than non-uniformities in the circumferential direction. In consequence, the performance can be correlated to a satisfactory degree of accuracy simply by using the radial blockage factor at inlet.

It is with great admiration and much humility that I am able to give this talk in front of Sir Frank Whittle, universally recognised as the genuine pioneer of turbojet propulsion in the formula that made a success of aviation.

As a matter of fact, the patent request filed by Sir Frank Whittle in 1930 (Fig. 1) comprised all the components of today’s turbojets: multi-stage axial compressor followed by a centrifugal compressor, combustion chamber, turbine coupled direct to the compressor and propulsion nozzle.

In April 1937, with the assistance of British Thomson Houston, Sir Frank Whittle ran his first turbojet on the bench at a thrust of 200 daN (Fig. 2). The year after saw the beginning of the Whittle Wl turbojet tests at a thrust of 380 daN. This engine was to receive consecration by a first flight in May 1941 in a Gloster E28/39 specially built for the purpose. Subsequently, this aircraft was fitted with a 650 daN version incorporating an air cooled turbine.

Features of aircraft which influence flow separations, and hence the onset of buffeting, should be always of interest to an aerodynamicist. The present compilation of such features is based on notes made during a visit to the USAF Aircraft Museum in Dayton, Ohio. Although two low-speed aircraft with high aspect ratio wings are considered, the emphasis is primarily on transonic and supersonic military aircraft, with wings of lower aspect ratio.

Some recommendations are made to stimulate research into improved methods to control flow separation, particularly for future transonic and supersonic aircraft.

The boundary element method is combined with the method of compatible deformations to obtain stress intensity factors for a cracked sheet reinforced with a repair patch. The method is applied to the analysis of a circular patch over a central crack in a rectangular uniaxially stressed sheet. It is shown that the proximity of the edges of the sheet to the patch edge has a negligible effect on the stress intensity factor of a crack completely under the patch.