The Society holds the view that the greatest source of weakness in the conduct of British aerospace affairs is the lack of continuous comprehensive co-ordination of the planning of the programme. Planning is proceeding in various ways in Ministries, industry, airlines and elsewhere. These efforts are inadequately co-ordinated and are incomplete especially in relation to the long term future. What is required is the gathering together, efficiently, of all the results of the planning by the customers and the industry, the filling of gaps in this planning and the moulding of all these into a rational, comprehensive and acceptable whole.

The Death of Miss Bradfield on 26th February 1967 at her home in Swanage will be regretted by a wide circle of friends. There can be few in the aerodynamic world of her generation who have not been influenced by her in one way or another and many will remember her with deep gratitude.

Born in 1895, the daughter of an eminent Wesleyan minister, she spent her early years in Ilkley, Yorkshire, and Wesleyan thinking and Yorkshire attitudes were ever prominent in her life. She read Mathematics at Cambridge, graduating as a Senior Wrangler at a time when the University would not yet confer degrees on women. Many of her early papers, therefore, have “Math, and Nat. Sci. Tripos” after her name. This experience may account for the somewhat pugnacious element in a personality which so impressively, stood out among so many men.

A brief review is given of the kinds of objective and subjective measurement required for systematic regulation of the aircraft noise around an airport, based on a maximum permissible noise exposure criterion. Some subjective factors are discussed and illustrated by test results.

Following a brief description of the basic radio aids and the terminology used, the paper discusses in some detail the differences between the original British and American approaches to all-weather landing; the different types of equipment resulting from these two approaches are broadly described. The mixing of ideas which occurred at the IATA Conference at Lucerne in 1963 and the more recent tendency towards a blending of British and American ideas are then discussed, and some predictions are made as to the form of the ultimate all-weather landing system. Certain Australian contributions to display research and the simulation of low visibility in flight are mentioned in context.

From the very start of aviation a suitable engine has been the basic pre-requisite for successful flight.

The first known Swedish proposal for a heavier-than-air flying machine was made in 1716 by the scientist and philosopher Emanuel Swedenborg. A steam engine, invented by him in 1714, was to provide the propulsion. His superior, “Royal Mechanicus” Christoffer Polhem, opposed the idea, and the project was abandoned without any attempt being made. More than 150 years later, in 1877, another Swede—Carl Rickard Nyberg, well-known inventor of the blow-lamp and other gas-producing devices using liquid fuel—presented a design for a helicopter and 20 years later still, for a steam-engine-driven aeroplane. The engine weight problem was to be solved by using a light tubular steam boiler, invented by him. Several prototypes were produced during the years 1899 to 1910 without being really flyable since the steam engine gave only 10 hp compared with the estimated 40 hp required.

It is a great honour to be asked to give the Barnwell Memorial Lecture. It is now nearly 29 years since Barnwell was killed test flying at the age of 57 an aeroplane which he designed and built himself. He was a man of many parts and a man for all seasons. It is a measure of the passing years that now there is a Barnwell Memorial Lecturer who did not enter aviation until three years after Barnwell's death and has never participated in the design of any aircraft. Yet Barnwell's ideas and actions have indirectly, anonymously and through others, had important effects on the life and work of myself and thousands of people like me. I did my operational flying in the last World War on Beaufighters, and in more recent years have been concerned with Britannias, both aircraft designed and built in Bristol by members of Barnwell's old team. It is curious to note that exactly 50 years ago Barnwell was sitting on a committee of the Royal Aeronautical Society charged with considering the future of the Society. We are still at it. At a meeting of the Future Activities Committee the other week, I wondered what Barnwell would have thought of the discussion and recalled Isaac Newton's remark that if we now see a little further it is by standing on the shoulders of giants.

Experiments on the influence of added narrow band sounds on the subjective assessment of noise were conducted at the NGTE 1966 Open Week and at the 1966 SBAC Show, with over two thousand people participating. The results clarify the apparently conflicting observations of earlier workers and show definitely that the presence of a narrow band content can significantly influence the degree of disturbance caused by noise of the type generated by aircraft near an airport.

Film cooling performance expressed in the terms of film effectiveness, is divided into initial and final regions containing respectively, the potential core and transition lengths and, the main decay region. The theory of Kutateladze and Leont'ev, which is representative of present approaches, is presented and shown not to apply to the film initial region. To resolve the questions, what is the minimum acceptable value of effectiveness in a given situation, and, what proportion of the resulting maximum permissible cooled distance is initial region, the film cooling of a hypothetical turbojet engine to power a Mach 2-2 cruise supersonic air liner is examined. Experimental data from cooling devices representative of current European practice are used in the analysis to give realistic results.

The force on a plane wire screen at right angles to the axis of a fully-developed, turbulent and effectively two-dimensional and incompressible jet has been determined. This study was suggested by the use of perforated surfaces in the operation of aircraft. Perforated landing and takeoff pads are used to reduce adverse ground effect, and the re-ingestion of burnt gases, on VTOL aircraft with centrally-located, downward-pointing jets. Perforated baffles are occasionally used to attenuate jet speeds during ground testing of conventional jet aircraft. The study is also relevant to a process in the making of paper. The pulp and water mixture is deposited on a moving screen (Fourdrinier wire), and the jet approaches the screen at an oblique angle.

The equations of motion of many mechanical systems reduce to ordinary differential equations with time dependent parameters. A single degree of freedom system, with the damping and restoring forces varying with time according to the law … m (t+k)nhas been studied using the WKBJ approximation. The general solution of the differential equation can be used to arrive at the response of such time dependent systems, subjected to excitations which are specified to be of either deterministic or stochastic nature.

In a recent paper, the author described some experiments in which the average base pressure on a two-dimensional bluff body was estimated from a random sample of instantaneous velocity measurements taken in the irrotational flow outside the separating boundary layers at the trailing edge. Although the oncoming stream was steady, the flow near the model was subject to a periodic disturbance emanating from the wake vortex street. An experimental check showed that the pressure estimates obtained by using the steady Bernouilli equation were reasonably accurate. This note points out that the method of data reduction used in ref. 1 is not an approximation; it is exact.