The computer is seen as the greatest invention in history, in that it has a universality which transcends all other known inventions. It will ultimately be capable ot any process describable in terms ot an open or closed logical structure.

In a deterministic science such as aeronautics, it has clear capabilities in the solution of the equations governing fluid flow, structures, propulsion, navigation and so on. The speed and size of future computers, together with all sorts of new software techniques, will facilitate almost instantaneous solutions of any problems, within the next century.

There will be two major constraints on these developments which we can predict with confidence. The first is financial. The second is more subtle: there may develop sociological resistance to technological advances, especially to those wielding the power implicit in future generations of computers, and this carries important implications for scientists.

From April to September of this year there will be numerous celebrations in honour of the Royal Air Force's 50th Anniversary, and it is highly appropriate that during this period the full plans for the Royal Air Force Museum are to be made public. The Museum is to be a new national institution maintained by the Treasury but built out of the sum obtained from a public appeal which is now in full operation.

A question constantly asked of all connected with this project is “who first thought of the idea?” The present writer has been told by at least a dozen men, all of them honest of eye and sincere of voice, that they and they alone were the only true begetter of the scheme, and it is a fact that every Station Commander who caused one or two aircraft to be preserved past the day of their official demise can feel that he and his men played some part in the slow development that has culminated in the present large-scale project.

In late September 1967, Her Majesty Queen Elizabeth II of Great Britain launched a new Cunard ocean liner in Scotland with the phrase, “Every great enterprise has an element of risk and uncertainty about it and I am sure no one can predict the future of our venture.” The launching of any new aircraft carries a similar connotation. For the jumbo jet as for the ocean liner, the risks should be recognised and, therefore, minimised because both the building of the ocean liner and the jumbo jet are extensions of a known art, not an introduction to unknown ventures such as may be true of the SST.

Size is relative. In its day, the DC-3 was called the “giant” air liner. If one compares the 21 passenger DC-3 with the 250 passenger DC-8, a twelve-fold increase, one can say that we are already in the jumbo jet age. The transition has been gradual through the Stratoliners, the DC-4, the DC-6, the Constellation, DC-7, Britannias, Vanguards, Caravels, Convairs, 707’s, and others. The results have been dramatic. (Fig. 1.)

A serious aircraft noise problem exists today primarily for one simple reason—aeroplanes make too much noise. The problem could be solved just as simply by getting rid of the aeroplanes, but aircraft have proved to be useful and, in most cases, even profitable investments. In the past few years, air transportation has become so widely used that it is now considered essential to the economic and social welfare of the citizen, as well as to the national defence of the United States, so some other solution must be found, one which assures the orderly development of air commerce, but which also recognises the rights of people on the ground who are adversely affected by the undesirable social by–products of this rapidly advancing technology.

The response of a P1a fighter aircraft to vertical and lateral harmonic gusts is calculated, and the predicted spectra for response accelerations at many points on the structure compared with previous flight measurements in continuous turbulence. The frequency range for the comparison is 0.45 c/s to 30 c/s and the response includes the short period pitching and the dutch roll rigid–body modes as well as oscillations in five symmetric and four anti–symmetric flexible modes. Structural flexibility is represented by measured vibration modes and aerodynamic forces are calculated by an oscillatory lifting surface theory.

A choked nozzle installation suitable tor the absolute calibration of air flowmeters over a limited flow range is described. An entry package is prescribed to ensure that near ideal flow conditions are presented to the nozzle. This package should remove swirl and flow distortions from most entry flows.

Provided that the instructions given in this note are followed meticulously then the quoted discharge coefficients for the nozzle may be guaranteed to better than ±0-25% at Reynolds numbers greater than 106. The overall accuracy of flow calibrations are then dependent only on the accuracy with which the mean gas thermodynamic properties and condition of state at the nozzle entry can be determined.

In their paper in the February 1967 Journal, Iyengar and Srinivasan have presented a solution to the problem of uniformly loaded clamped skew plates by employing characteristic functions for the modes of vibration of clamped-clamped beams. They compared their theoretical results with those obtained by Morley and Kennedy.

The writer has recently extended the 3-parameter solution by assuming a deflection function in the form:

The natural frequencies of vibration of a cantilever beam allowing for rotary inertia and shear deformation are obtained by the approximate Ritz method.

The workability of the method is dependent upon the approximating functions chosen for the dynamic displacement curves. A series of characteristic functions representing the normal modes of vibration of cantilever beams in simple flexure is used as the approximating functions for both deflections due to flexure and shear deformation. Good agreement is shown between frequencies obtained by the Ritz method and those resulting from an analytical solution.

The effect upon the natural frequencies of allowing for rotary inertia alone is shown and it is seen to increase rapidly with mode number.

Experimental results are presented of the measurement of the ratio of the wall shear stresses at the inner and outer surfaces of concentric annuli. Five radius ratios were investigated with Reynolds numbers in the range 2000-89 000 with air. The Reynolds number is defined as where ū is the bulk velocity.

It is concluded that the ratio of the shear stresses is very different from the corresponding laminar flow value and is a function of both radius ratio and Reynolds number.