This is a great occasion; I feel quite unworthy to do justice to this commemoration of a great man and a revolutionary event and to become one of the illustrious band who have so graced this occasion in the past. For the more one reads about the Wrights' achievements, the more one is impressed by them as men of stature—of great character, determination and intellectual strength with a most endearing modesty. They had too, such a sense of fun and there is a golden thread of family affection running all through the record. They were men of vocation just as their father, Bishop Milton Wright, and there is no doubt of the influence of the family ties on what they did. One senses how much home meant to them and how much they all turned to Katharine, the womanly stabilising element. A comment of Wilbur's in one of his letters to George Spratt commenting on a technical argument they had been having, is very revealing. "It is a characteristic of all our family to be able to see the weak points of anything", a vivid hint of most lively family discussions, and of course, this most rare combination of brothers must have been a fundamental element in all their work.

The problems involved in the packaging of Service radar equipment are reviewed. Information on shock testing techniques, instrumentation and a design procedure for cushioning are given, together with some examples of current packaging methods used by the Ministry of Supply's Radar Research Establishment, Malvern, Worcs. The paper is based on a lecture given to the Royal Aeronautical Society, Gloucester and Cheltenham Branch in December 1954. Received October 1956.

This paper assesses the application of a new method for system stability analysis, the weight functions method, to the longitudinal and lateral motions of a High Incidence Research Aircraft Model. The method consists of finding the number of weight functions that is equal to the number of differential equations required for system modelling. The aircraft’s stability is determined from the sign of the total weight function; which should be negative for a stable model. The Aero-Data Model In Research Environment (ADMIRE) simulation, developed by the Swedish Defence Research Agency, was used for the aerodynamic aircraft modelling, with the following configurations: Mach number = 0·25, altitude = 500m, angle-of-attack [–10 to 30]°, elevon deflection angle [–30 to 30]°, canard deflection [0° and 25°] and rudder deflection angles [–30° and 30°]. These flight configurations were selected because they are among the flight conditions for Cat. II Pilot Induced Oscillation (PIO) criteria validation, performed on the FOI aircraft model presented in the PIO Handbook by the Group for Aeronautical Research and Technology in Europe, Flight Mechanics/Action Group 12. This aircraft model has a known instability for longitudinal and lateral motions and so a control law was introduced to stabilise its flight.

The problem of bending of thin elastic plates has interested mathematicians and engineers for many years. Various methods have been put forward for determining the approximate solutions among which the variational method of Ritz is most common. This procedure leads to a system of linear simultaneous equations, the solution of which is often quite tedious, although generally by taking a few rows and columns quite accurate results are obtained. The purpose of this note is to show that by using bar eigen-functions for plates which are either clamped, or when some edges are freely supported, certain simplifications can be made in the process and the difficulty of solving simultaneous equations can be avoided; and that the deflection surface of the plate can be derived directly in a series form.

The natural frequencies and modes of vibration of a structure may be obtained more or less directly from experiments. The generalised masses and stiffnesses, however, are usually obtained indirectly from experimental investigations of the dynamic behaviour of the system. One of the techniques widely used for this purpose in the aircraft industry is known as the method of displaced frequenciesm.Stated briefly, the method consists of observing the changes in the natural frequencies caused by the addition of one or more small masses to the vibrating system.

It has been known for many years that the rectangular wing stalls first in the central region, burbling spreading gradually tipwards with further increase of incidence. This phenomenon is useful in connection with lateral control, because this control is retained for a while (though reduced) past the stall. Increased use of the1 tapered wing to-day raises the question of whether this phenomenon holds good with tapered wings. There is already some doubt on this score.

These notes are intended to summarise for the benefit of aeronautical students the basic requirements of nose-wheel steering hydraulic systems. The various factors which have to be considered are listed and representative solutions given.

The preceding symposium papers have indicated the saleable developments on offer in the constituent parts of the civil transport system and their collective impact in aircraft project terms is covered in the paper by Brown and Lawson.

As the aircraft industry matures performance gains come less readily and costs have become a much greater determinant of progress. This paper therefore considers some of the fundamentals of cost reduction. This topic cannot be considered in isolation; cost reductions must be balanced against product effectiveness and there are major interactions between possible cost levels and sales volume. Thus, it is necessary to treat the subject in the broader framework of commercial viability. This paper attempts this task. It starts with the more direct cost questions, considers market interaction factors and concludes on a positive note by a critical review of the investment decisions needed, many of which are urgent and of critical importance to the future of the industry.

Since it is too complicated to obtain analytically the stress distribution in a plate containing two reinforced circular holes under uniaxial tension, the stress distribution along the inner edge of a reinforcing ring will be determined experimentally in this report.

The relationship between σθ/p at the inner edge of a ring, the dimensions of a ring and the distance between the centres of two holes will be investigated. Experiments are done in the cases when the uniform load is applied in the perpendicular or parallel direction to the centre line (see Figs. 1 and 2).

The recent war has provided a great deal of experience in the operation of aircraft and ground equipment under a variety of conditions. This paper is an attempt to condense and correlate some of the points noted into a logical sequence. It is not based on statistics and is more in the nature of a selection of problems and impressions about them. Possibly this is an advantage, as it seems doubtful if many logical conclusions could be drawn from a set of completely comprehensive observations, even if these were available.

Work on the Goblin engine was started in 1941 when, at the invitation of the Ministry of Aircraft Production, the de Havilland Enterprise began to interest itself in jet propulsion. At this time de Havillands were much in ignorance of the work of Air Commodore Whittle, the Royal Aircraft Establishment and the Gloster Company in this field. The first step was to study what had already been done and in this connection the fullest co-operation was offered by all concerned. The author would like to express the appreciation of the organisation with which he is associated for the material help received in those early days by way of advice, data and drawings. As a result, it was possible to start fully abreast of what was being done in this country. The benefits of further experience and mutual assistance from the pioneers in jet propulsion were fostered by a process of frank discussion and exchange of information, finally to be cemented by the formation of the Gas Turbine Collaboration Committee.

Steady, constant-density, two-dimensional flow in a laminar boundary layer is considered over a permeable curved surface, for conditions such that the equation of motion has similar solutions. Account is also taken of the displacement of the main stream by the boundary layer.

Integration of the equation of motion on a digital computer yields results indicating that, for given values of curvature and longitudinal pressure gradient, suction reduces the boundary-layer thickness and increases skin friction. Blowing has the reverse effects. The amount of suction or blowing required to produce neutral stability is independent of curvature and so may be deduced from data for flat surfaces.

For a given curvature, blowing reduces, whereas suction increases, the magnitude of the adverse pressure gradient which the boundary layer can withstand before separation occurs. For a surface through which there is blowing or only a small amount of suction, convex curvature also reduces the magnitude of the adverse pressure gradient producing separation; but for larger amounts of suction the effect of surface curvature on separation is reversed.

The up-to-date engineer or scientist would not challenge the growing importance of the modern large-scale digital computer in research and development. Yet, while we all agree that computers are important and useful, we disagree from one discipline to another and often within the same discipline on just what the computer contributes or can possibly contribute to research and development endeavours. The difference in approach to computer usage is more one of philosophy than of technique. Indications are given from our recent work that some philosophies of computer utilisation may be more fruitful than others. The availability of the large-scale digital computer has not only facilitated, but directly inspired and shaped the matrix methods for analysis of continuous media and structures, both in the linear and non-linear regimes. Without the availability of a modern computer all this work is literally meaningless.