It was easy for me to choose a subject for this lecture. First, turbulence is an important part of engineering fluid dynamics which has not so far been treated in the Reynolds-Prandtl lectures; secondly, it is the most obvious link between the careers of our two heroes; and thirdly it is the only scientific subject on which I am even remotely qualified to lecture before such a distinguished audience. The first and second propositions are sufficiently demonstrated by the annual consumption of something of the order of 1010kg of kerosene to overcome the effects of Reynolds’ stresses in Prandtl’s boundary layers. Have any two human beings ever had such a spectacular memorial? (Yes, Lanchester and Prandtl, to whose induced drag we sacrifice another 1010kg of fuel each year.)

The aviation industry, by definition of its products and their utilisation, is international. It may shortly become interplanetary. BOAC, by whom I am employed, operates its aircraft all over the world and employs staff in more than fifty countries. Our staff includes a very wide cross section of trades and professions, from aircraft cleaners to pilots, architects and lawyers, but with a few exotic exceptions, our industrial relations do not differ substantially from any other modern industry in the UK.

Under the Civil Aviation Act there is a responsibility on the Airways Corporations to establish machinery for the determination of terms and conditions of employment and consultation with the staff they employ. There is, equally, a responsibility upon the Boards of the Corporations to recognise those unions who are appropriate to the grades of staff they employ.

The machinery, which was created in 1949, was based on the concept of Whitleyism but its application had to be rather wider than was the case in other industries because:

• (i) Civil aviation was in its infancy at the time

• (ii) The formidable task of bringing together a wide variety of skills

• (iii) The problems of adjusting to the varying practices and philosophies of unions catering for a wide variety of occupational groups.

Any assessment of industrial relations must start with consideration of the character of the industry in question. It would be, for example, impossible to understand the behaviour of the modern miner without some knowledge of the history of the coal industry. Aviation has only a brief history. It nevertheless has a flavour of its own.

Three distinctive features are of note. To the outsider it is clear that the aviation industry brings with it the sort of challenge which appeals to the enterprising and the romantic. It is therefore no surprise that the industry has more than its fair share of strong character. There exists an independence of outlook on both sides of the industry which is not always easy to control within the normal industrial relations framework.

The main object of tests on models in wind tunnels is to obtain results of direct application to aircraft in flight. Unfortunately, the flow about a model in a wind tunnel is subject to constraints that are absent in flight, and so allowance must be made for these wind tunnel interference effects for the results to be meaningful.

There is a considerable body of information on the sources of wind tunnel interference and, so far as effects in steady flow are concerned, methods of estimating the corrections to be applied are generally available. They enable results of wind tunnel tests to be reduced to equivalent flight results with some measure of confidence. The situation is far less satisfactory for oscillating models. The additional interference effects due to frequency of the motion may be of too complex a nature or require too tedious a computation (particularly for a deforming model) for a reliable reduction of the results to flight conditions to be practicable.

This paper represents a second stage in a continuing theoretical study of aircraft longitudinal responses to random turbulence based on stationary random process theory. In previous papers the spectral gust alleviation factor for eg normal acceleration, was studied in detail. In the first, the aircraft was assumed to be rigid, responding only in heave, and the effects of unsteady aerodynamics were K, systematically considered. Wherever possible, comparisons were made with previously published work. For the published version the report was revised and expanded to include some results for the pitching aircraft but this analysis was not complete. This paper is concerned with a more complete analysis of the longitudinal responses of a rigid aircraft, free to heave and pitch, flying through random turbulence. The turbulence is assumed to have a power spectral density function described by the Dryden model.

Until a few years ago it was the practice to neglect lift interference on oscillatory model tests in high-speed subsonic wind tunnels, whatever the working section configuration. However, in 1960 Bratt and Wight discovered a large interference effect on the pitch damping derivative of an M-wing measured in the slotted working section of the 25 in x 20 in tunnel at the National Physical Laboratory. In 1964 Wight reviewed a number of oscillatory tests and showed that in many cases there were significant interference effects on both stiffness and damping derivatives when measured in slotted working sections.

Following the publication of my paper “Pilcher and the Multiplane” in the May issue of the Aeronautical Journal, I have had cause to reperuse the various accounts dealing with the operation of the “gust damping” device used by Chanute on his quadruplane and probably adopted by Pilcher for the multiplane.

Referring back to the original patents, which I had read thoroughly during the preparation of the paper, I realised that I had omitted to mention Chanute’s proposal of the deliberate operation of this system as a positive means of control.

A Large part of industrial engineering effort is devoted to “work study”. This term is put in quotes since the activity as practiced is more than just “measuring” the time associated with some particular work activity. In practice, the engineer also selects certain elements of an operation where possible to improve the method and procedure. In other words, “work study” really means a complete study and description of the operation. When referring to the “program” one must also consider a control system of daily, weekly or monthly reports whereby countable output can be related to time input.

The Report of the Commission on the Third London Airport tells the story of an interesting exercise in airport location. It includes what is possibly the most extensive cost benefit analysis ever undertaken for a civil project and it tells of an experiment in decision taking in a democratic society. At the time of writing this paper the report has been published for a little over three months but the Government has not yet announced its decision. After publication of the report there was an immediate popular outcry against the recommendation of an inland site and it now looks likely that the Government will not accept the recommendation.