A survey is made of the effects on aircraft of the main atmospheric factors and of the way they are dealt with, in design and operation, at the present time. Possible developments in the pattern of the relationships of aircraft to the atmospheric environment are discussed, in the light of expected advances like operational VTOL, and orbital-type flight, reliable weather forecasting, and effective turbulence avoidance and gust alleviation systems. These developments should all be conducive to safer and more comfortable flight. Marked further benefits would accrue from weather control in the vicinity of airfields, of which there are some prospects, improvement in en-route operation through weather control appears less probable, and the prospects of smoothing turbulence ahead of the aircraft are speculated on.

The NASA Langley Research Center has conducted an intensive and broad research programme on supersonic cruising aircraft for some 10 to 12 years. During the course of this effort to advance the state of technology of supersonic flight, a number of interesting research or design techniques and approaches have evolved. Several of these which have application to present and future aircraft design are discussed. The use of highspeed computing equipment in the application of linear theory to the problems of optimising supersonic cruising efficiency is treated. Experimental techniques employed in the study of drag at transonic speeds in wind tunnels are described. In the area of aircraft operations, attention is directed toward unique simulation methods employed in studying the relationship between air traffic control systems and supersonic aircraft.

Propulsion systems selected for commercial transports must provide efficient and reliable performance over a broad range of conditions. These aeroplanes are used over both short and long route segments, on non-standard days, and at a range of altitudes to meet air-line schedule requirements.

This paper covers some of the design parameters that were considered in the integration of the induction system, secondary air system, jet nozzle and the basic turbojet gas generator for the SST. During recent years some of the most important gains in propulsion efficiency have resulted from the development of inlets, engines and exhaust nozzles which are matched over a broad range of operating conditions. An efficient propulsion system for a supersonic transport depends upon very close matching of these components. This, of course, requires a better understanding of the capabilities and limitations of each of these major components. For the supersonic transport, 50% or more of the gross weight will be comprised of propulsion system and fuel and less than 10% will be payload.

The first part of this paper, published in the May JOURNAL, discussed in general terms certain topics relevant to business objectives and industry orientation and dealt in some detail with definition of company objectives and strategic plans. The successful completion of this first phase is dependent on close co-operation between Government and Industry for both civil and military projects.

This part of the paper deals with the procedures for implementing the strategic plan (management control) and the application and control at operational levels (operational control). The phase of implementation is one where considerable scope exists for ensuring future effectiveness through sound direction in that the plan becomes a firm commitment at this stage.

The paper concludes with a brief summary and a list of recommendations for future activities within the Management Studies Group of the Society aimed at definition of a basis for application of the disciplines described in the paper.

In a world in which Engineering, Technology and Science play an increasingly dominant role, the prosperity of Britain with its limited natural resources depends more than ever before on the skill of its population. The proper education, training and optimum utilisation of its manpower is therefore vital. There is strong evidence for anxiety as to the recruitment, supply and use of scientists, technologists and engineers who create the knowledge and organise the human effort required for its successful exploitation in industry and commerce upon which our whole economy depends. These three highly skilled professional groups are interlinked and interdependent.

It was pointed out in ref. 1 that various interpolation techniques could be used to develop elements (for the matrix displacement method) of increasingly more complex characteristics both as far as geometry and specification of strain are concerned. A number of authors have examined this problem in detail and attention is drawn to the excellent work of Bogner, Fox and Schmit on plate elements, and to the elegant paper by Pestel. Over a number of years the ISD at the University of Stuttgart has investigated the application of interpolation functions and has developed within the ASKA language a number of corresponding elements.

Following the appearance of my note on this subject in the July 1967 JOURNAL, Professor Hemp kindly pointed out a mistake in one of the basic assumptions. This has led to a recalculation of the results, and the correct results are given below.

a width of beam

b lower bound on height of beam

d upper bound on height of beam

E Modulus of elasticity

h (x) height of beam at position x

H the Pontryagin Hamiltonian

i second moment of area=ah3/12

i length of beam

M (x) bending moment =

rl, r2non-dimensional length parameters

p density al lengthparam

t non-dimensional length parameter=x/l

u non-dimensional length parameter=h/l

x horizontal distance from base of beam

y (x) vertical displacement of the centre-line of beam

Y error function in hill climbing sequence

Vectors

f phase space velocity vector =dX/dt

P adjoint vector

X non-dimensional state vector

The investigation of Daum focused attention on the problem of condensation in hypersonic wind tunnels. In such tunnels there is often a conflict between the desire to obtain the maximum Reynolds number and the necessity of operating with a sufficiently high stagnation temperature to avoid liquefaction of the working gas. The hypersonic gun tunnel, in which the present tests were made, is capable of running at relatively high Reynolds numbers and to define the operating limits of the RARDE gun tunnel, Bowman made measurements similar to those of Daum, but using nitrogen as the working gas. It will be recalled that Daum made measurements of static and pitot pressures at varying temperatures. He deduced from these measurements that below a certain working section pressure significant degrees of supersaturation could be tolerated before breakdown to the condensed state. Thus three regions can be defined; in order of increasing temperature these are:

(i) condensing flow;

(ii) supersaturated uncondensed flow; and

(iii)unsaturated flow (see Fig. 1).

In the design of geared rotating systems in engineering practice a variety of configurations are used, and their torsional vibration has been extensively studied. Detailed analyses of the modes and frequencies of vibration of these systems have been given by Ker Wilson and Nestorides. When the rotating system is rigidly supported, standard methods may be used to obtain the characteristics of free vibration and the response to impressed forces, from which the transmissibility of the gear-box may be calculated. However, there are many applications in which the gearbox is flexibly mounted. The simple example of a geared engine with a flexibly mounted crankcase has been considered by Den Hartog and Butterfield. In some epicyclic gear-box assemblies, elastic elements are introduced between the reactive element and the gear-case to increase the capacity for absorbing impulsive loads and as a means of varying the natural frequencies of vibration'. Harmonic forces acting on the rotors excite coupled vibration of the rotating system and the supporting frame, and Ker Wilson has shown how the natural frequencies and modes of the combined system may be determined by Holzer-type tabular methods. This involves a trial-and-error technique which may sometimes be tedious. Vibration of geared systems may also be excited by the motion of the frame supporting the gear-box, and an analysis of the response is necessary in the determination of dynamic loads.