Developments in computer technology will result in a capacity for structural analysis and definition of structural geometry in intimate detail, and this capacity will be used to the full for design and fabrication in the relatively brittle materials of high specific strength and stiffness that will become commonplace. However, only evolutionary developments in basic structural form are anticipated for the future, with stressed-skin structure remaining dominant. The structure will be windowless.

Mass-produced personal aircraft will be required for leisure purposes, and glass is likely to be a favoured structural material for these.

On 31st December 1966, General McKee of the Federal Aviation Administration announced that The Boeing Company and the General Electric Company had been selected to develop the prototype airframe and engines for the United States supersonic transport. The announcement ended a long, intense competition and was the culmination of the nine years of effort on the part of Boeing, where since January 1958 there has been an identified, separate project devoted to the SST.

I think that by now ELDO is sufficiently well known that I can assume its purpose and aims need no long explanation. I would prefer to give first a summary of its present situation, its achievements and the experience which has been gained; and at the end I shall give an indication of ELDO studies aimed at future activities.

The purpose of this paper is:

• 1. To describe the technical content of the ELDO-PAS Programme;

• 2. To give an outline of the management procedures used by the ELDO Secretariat.

The presently approved ELDO programmes are:

• (a) The Initial Programme as described by the ELDO Convention aiming at the development of the threestage Europa I Launcher.

• (b) The Supplementary Programme approved by ELDO Member State Ministers in July 1966 to give ELDO the capability of placing significant payloads in geo-stationary orbits.

The function of any guidance system selected for the Europa rocket is to generate steering demands in such a way that—

1. (a) the trajectory flown results in a minimum consumption of fuel and

2. (b) the required orbital velocity and height at injection are achieved with the maximum accuracy.

If a system can be devised which enables these two aims to be realised, useful payload will not be sacrificed to place a satellite in its desired orbit.

This paper is based on a lecture given to a meeting in June 1967 sponsored by the Royal Aeronautical Society and Business Operations Research Ltd. It describes the activities of the operations research functions in Aer Lingus and is based on the work both of the central Operations Research Unit and, also, on studies carried out by management science specialists in the Aer Lingus Economic Planning Department.

I am especially honoured to be invited to deliver the inaugural address of the newest branch of the Royal Aeronautical Society here in Ireland, with your exceptional contribution and involvement in both the pioneering and progress of commercial air transport. It is also a great pleasure to have my old friend Captain Jack Kelly-Rogers, one of the world’s truly great aviators and most appropriately your first Chairman, officiating tonight. As President of the Weybridge Branch of the Society I also bring you their greetings and best wishes.

The description of the LUMINA element in T.N. 11 is followed by another three-dimensional interpolation element, called HERMES 8, available in the ASKA language and briefly mentioned in ref. 1. Just as the LUMINA set, the HERMES element represents a general hexahedronal element with curved faces and has proved a most useful component block for three-dimensional analysis of complex bodies. The cardinal idea underlying the HERMES development aims at combining the advantages of the Lagrangian and Hermitian interpolation techniques.

Following on from the LUMINA and HERMES elements discussed in TN’s 11 and 12, this note analyses two further three-dimensional elements outlined in ref. 1. These new elements possess the desirable features of completeness and consequent invariance of the polynomials for the displacement fields. It has been shown in ref. 2 and stated in ref. 1 that third order complete polynomials yielding a second order or parabolic strain distribution fit into a tetrahedron element with 20 nodal points and 60 degrees of freedom, denoted within ASKA as TET 20 (Fig. 1).

Theoretical data from lifting-surface theory are presented to illustrate

• (i) that the vortex drag factor is closely related to the half-wing spanwise centre of pressure on simple planforms without camber or twist,

• (ii) that lifting-line theory is useless for predicting the spanwise distribution of vortex drag on swept wings,

• (iii) that recent numerical improvements in lifting-surface theory help to reconcile the concepts of wake energy and leading-edge suction in relation to vortex drag.

This paper lists all the known published work on the development of automatic selection of redundancy techniques over the past decade. The main interest is a selection technique based on an algebraic procedure. It is emphasised that such a technique is very flexible in its application and that the redundancy selection can be completely automatic, completely preselected but automatically imposed or a combination of the two. This enables previous experience to be applied. The criterion is given for optimum redundancy selection and items which influence this are discussed. It is pointed out that the basic and redundant load transformation matrices can be generated automatically for general configurations.