This is a personal attempt to take a long view into the Second Century and to describe prospects for further possible developments in aviation, with particular emphasis on the part played by aerodynamics in the evolution of aircraft. The overall view is necessarily broad and wide, and the material is taken from the results of earlier papers(1-2). An attempt is made to put the future prospects into the perspective of past developments, and it is concluded that aviation can look forward not only to a vast expansion on the technical side into most promising and as yet unexplored fields, but that it may also be built into a more rational social system with the aim of serving mankind as a whole.

The safety target for the Supersonic Transport has been set by the governments sponsoring the project. This is to achieve a safety level at least as good as that of subsonic aircraft at the same time. An analysis of present accident trends is used to give more precision to this statement. If the present rate of improvement in safety continues, the accident rate in the early 1970's can be expected to be some 20% to 25% below today's figures and the target for the SST must be for an improvement of at least 30%. To achieve improvements of this order in a safety record which is already good requires considerable effort by all concerned and necessitates a more scientific approach to safety requirements, especially airworthiness requirements. Some examples of the way this is being done in the United Kingdom and f ranee are given.

A submersible is defined as a neutrally buoyant submarine which relies largely on the buoyancy of the hull rather than gas or liquid filled floats at ambient water pressure. 29 different kinds of submersible have been built in USA and 15 in other countries. One has been built in England. Half of these do not go below 2000 ft and one third do not go below 1000 ft. The minimum safe weight for a vehicle is 5 tons at 1000 ft and 10 tons at 20 000 ft. A useful research or light work vehicle must be twice the minimum weight, and a heavy work vehicle in the 30-100 ton range.

High utilisation factor can only be obtained with special handling and support equipment, underwater navigation aids, high manoeuvrability, and a reserve of speed, life support, payload, and endurance. Principle applications of submersibles are in scientific research, geological mapping, prospecting, the oil industry, dredging, pipe-laying, and search and salvage.

The seven year life of the Ministry of Aviation was a time of dramatic change, not only in engine technology, but also in defence and procurement policy, in industrial organisation and in the public image of the aircraft industry. The rapid increase in the cost of developing and producing new aircraft and weapon systems made development management and cost control issues of the greatest importance and much effort was devoted to devising improved management procedures. In summarising the technological achievements of the period, attention is particularly drawn to changes in engine noise characteristics, in selling price and in the growth of overhaul life and reliability. The nature of engine development is examined in some detail and it is pointed out that the development content of engine programmes is normally much greater than that of airframe programmes. The high development effort and expenditure demanded by aero engines is explained and justified. Attention is drawn to the relationship between development cost and (a) manufacturing cost, (b) the magnitude of technical advance.

Some of the problems encountered in the search for an effective system of cost estimation and control are indicated.

The problem of transferring a space vehicle between two points in a given gravitational field such that the minimum amount of fuel is used has been called the fundamental navigational problem of astronautics. In such a problem it may be required to find the optimum thrust magnitude and thrust direction which yields a minimum fuel trajectory. Furthermore, certain end conditions may be specified which the optimal trajectory must satisfy. In a large number of published papers the velocity of the vehicle is supposed known both at the beginning of the transfer and at the end whereas the time taken to complete the manoeuvre may or may not be given. Also, other performance criteria have been chosen besides minimum fuel. For example, minimum time of transit or maximum orbital altitude at perigee.

Papers mentioned in this review deal mainly with flight in two dimensions apart from those sections on general theory. Furthermore, all space vehicles considered are assumed to have a fixed exhaust velocity unless otherwise stated.

Recently there has been renewed interest in the concept of an all-wing aircraft as a means of producing cheap air transport over relatively short distances. It is natural that with the large amount of information on slender wings now available an all-wing aircraft based on a sharp-edged slender planform should be considered for this role. One of the difficulties immediately faced in developing this concept is that since the aircraft must carry a large number of passengers it is necessary that as much of the wing area as possible should be deep enough to provide for a large passenger cabin. Thus the wing will be very thick over a large part of its area. If this condition is not met, then the aircraft has too much wing area and hence too high a structure weight. Typically one may think of an aircraft with a delta wing of aspect ratio 2 and with a wing thickness of from 15% to 20% of the root chord over as much of the wing area as possible. At first sight thickness of this order eliminates the main advantage of slender wings since the effect of thickness is usually to reduce the strength of the leading-edge vortices and hence the non-linear lift. Thus the incidence for a given lift is increased above that for a thin wing. This in turn means that the lift-to-drag ratio may be smaller.

Tables of equilibrium thermodynamic properties of the ionized gas formed behind strong shock waves in Helium are presented, in the Mach number range 10 to 30, for initial pressures of 0-1, 0-5, 1, 5, 10, 50, 100 torr. The effect of the inclusion of the full partition function series is demonstrated in the Mach number range 20 to 30.

A numerical solution has been developed such that the only experimental quantities required for its use are the shock Mach number and the pre-shock conditions.

A method of analysis is presented for the interaction between the local and torsional modes of instability of a stiffened panel in compression. Numerical results are produced for the particular case of a panel with Z-section stringers, and the influence of the flange width on the buckling stress is illustrated.

This work deals with theoretical aspects of thrust vector control in rocket nozzles by the injection of secondary gas into the supersonic region of the nozzle. The work is concerned mainly with two-dimensional flow, though some aspects of three-dimensional flow in axisymmetric nozzles are considered. The subject matter is divided into three parts. In Part I, the side force produced when a physical wedge is placed into the exit of a two-dimensional nozzle is considered. In Parts 2 and 3, the physical wedge is replaced by a wedge-shaped “dead water” region produced by the separation of the boundary layer upstream of a secondary injection port. The modifications which then have to be made to the theoretical relationships, given in Part 1, are enumerated. Theoretical relationships for side force, thrust augmentation and magnification parameter for two- and three-dimensional flow are given for secondary injection normal to the main nozzle axis. In addition, the advantages to be gained by secondary injection in an upstream direction are clearly illustrated. The theoretical results are compared with experimental work and a comparison is made with the theories of other workers.