During recent years a major research programme has been undertaken at the National Gas Turbine Establishment into the subject of circulation control and its application to lifting rotors. In the case of rotors intended to be used on helicopters and stowed rotor aircraft, a very important part of the research work is the examination of rotor behaviour in forward flight. Traditionally, this has been investigated mainly on full-scale aircraft but more recently model scale experiments have been done in wind tunnels, particularly in the USA where there are a number of suitably large tunnels.

I was glad to be asked to talk to the Graduates’ and Students’ Section of the Society because, in the years to come, it is you who will be carrying some of the responsibility for developing the air transport industry of this country to extents which will make today's efforts appear puny. In an industry which is doubling in size every five years—a fourfold increase during the next decade—it is important that we get the structure right. There is a chance to do this now, while the whole future of British commercial aviation is under review that may not, indeed should not, occur again for many years. Change inevitably brings disruption and upheaval but some re-organisation and re-orientation is essential if the industry is to have an expansive but reasonably stable future bringing greater efficiency, higher profitability and enhanced benefits to the national economy. The recent White Paper Civil Aviation Policy holds out little prospect that, under a Socialist Government, these aims will be fully realised in the Seventies.

The design and development of aircraft powerplants for sustained supersonic operation proves to be an exacting task which involves careful balancing of the requirements for high installed performance and system viability. The latter question may be dominated by the need to ensure flow compatibility at the intake/engine interface.

The recording of aircraft operational data in service has long been considered to be a desirable addition to the data available to an airline. A limited amount of this information has always been provided by the pilot's log, but the capability of recording this data automatically has been delayed until recent years by the lack of recording systems which were both reliable and yet not too costly to the airline's overheads. The availability of possible systems in the immediate post-war years led to attempts to introduce governmental regulations covering the provision of such systems, but it was not until 1958 that the design of reliable airborne systems led to the introduction by the CAB of the first American regulations for this type of equipment. These American regulations were followed by other countries, notably France, Australia and the UK. The mandatory use of aircraft flight recorders derived from government requirements to record a limited number of flight parameters to assist in the evaluation of aircraft accidents.

It can be said that the main cause of premature failure or malfunction of any engineering component is attributable to the design being below the standard required for the environment in which it had to exist. This idea is neither surprising nor new, and applies throughout the whole field of engineering, especially in the aircraft industry which is extremely conscious of the need to design and develop its systems to suit the environmental conditions of flight.

In the air-breathing engine industry this need has been recognised almost from the inception of flight. For the successful development of an aero engine there is, therefore, the need to use all the resources of past flight experience to provide initial design information for the engine and its components, and then to test the engine or components to determine that the requirements have been fulfilled.

On 3rd December 1903, with the wind gusting up to 25 mph (11·2 m/s), Orville Wright staggered into the air in a flimsy aeroplane powered by a four-cylinder piston engine, and, with that event, the Wright Brothers had added a new dimension to man's ability to travel (Fig. 1).

Their success was not just a piece of luck, but the result of years of study and experimentation, coupled with great personal effort in the design and manufacture of their aircraft. Like all pioneers, they were faced with important gaps in the availability of suitable equipment, particularly an engine of sufficient power and light enough in weight, and a propeller of high enough efficiency. These they had to develop for themselves.

Compared with most other industries a distinguishing feature of the air transport business throughout its history has been the rapid development and replacement of its flying equipment. Aircraft have evolved to meet the needs of expanding traffic and each generation has been succeeded by different, newer and better versions. The thirties saw the appearance of the all-metal monoplane with piston engines and propellers.

Before considering the techniques used for in-flight thrust measurements, it is important to understand fully the basic reasons for such measurements.

For without this understanding it is difficult to assess the benefits to be gained from making accurate thrust measurements. Those readers who are actively involved in performance prediction and measurement on new aircraft will already be aware of many good reasons, but a brief review of the situation will help to set the scene.

The general adoption of the International System of Units (SI) in engineering as well as in science makes this the time to relinquish the slug, an engineering unit of mass. Seldom has a convenient unit proved so contentious. This note sets out salient points in the controversy, and indicates basic issues which could scarcely have been appreciated universally at the time.

In essence the slug is the unit of mass that goes with the pound force or the pound weight, just as the poundal is the force unit that goes with the pound-mass. There has, however, been a great deal of argument as to whether it is a true derived unit or simply a fundamental unit in disguise, and about how to realise it in practice: in particular, if unit force is defined or established by reference to the gravitational force on the pound-mass, there arises immediately the question of the appropriate value to use for g, i.e. should it toe the local value, the value at a specified place, or some other agreed standard acceleration?

The high cost of new weapon systems and the loss of tactical capability when vehicles are out of operation for unscheduled repairs are forcing the military services to require a higher order of structural reliability. Fleets are being kept in operation for many years beyond the time originally anticipated during design, resulting in many cases, in the need for costly structural repairs and modification to cure fatigue problems. Consequently, new weapon system procurement contracts are being written with a “fatigue-life” guarantee as a contractual requirement. This situation calls for careful attention to details during the design phase. More testing, both exploratory to aid in detail design decisions, and confirmatory to validate the design and demonstrate compliance with the contractual requirements, is required. Better test methods and more meaningful test results are demanded from the test laboratory. Methods for more accurate predictions of the loads experience during the entire service usage are required of the structural analysts.

The first question that a prospective lecturer of the august series in honour of Frederick William Lanchester should ask himself is the possible reason why he has been selected. I confess that for a considerable time I have been at a loss to understand this signal honour bestowed upon me. My mind ventilated a number of possible explanations starting from the evident but rather tenuous reasoning that both the eminent Mr. Lanchester and myself can show a connection with the leading Technological Institute of Britain, the Imperial College. But is this sufficient as a justification? I doubt it. Another path I tried to explore ventured along the intriguing intentional verbal slips and monumental sayings of Lanchester. Is it possible—I asked myself—that the wise Council of the Royal Aeronautical Society selected me on account of my undeserved reputation to have been in my Golden Youth an angry young man, an enfant terrible, and an early exponent of the anti-establishment criticism.

This paper is a revised version of a contribution towards the work of the Society's Future Policy Committee's Working Party on Effectiveness in R & D. An abbreviated version of the Working Party's report was published in the September 1969 Journal.

The R & D process in any sphere exhibits features of uncertainty in many of its phases and it therefore seems appropriate to examine aeronautical R & D from a probabilistic viewpoint. Before discussing the origins and treatment of these uncertainties it is necessary to define Research and Development in the aeronautical context and to state its aims as seen by the author.

Certainly one of the most important elements in today's spectrum of military weaponry is the tactical guided missile. Few developments have offered a greater opportunity to increase the fighting potential of our military forces. As it happens, however, few developments have caused the frustrations and problems along their path to fruition that have been associated with the tactical guided missile.

In selecting armament for a particular role, the merits and demerits of each class of weapon must be considered to arrive at that which is best for the particular application, and as such the guided missile must be viewed as just one of the possible candidates to be evaluated in its turn. The guided weapon often wins, of course, for it has certain unique characteristics that give it a number of advantages. But it is common now to find that in some applications that a decade ago would have been conceded to the missile, that guns and other types of “conventional” ordnance may be better.

Air Cdre. Harland dealt with Project Management at Mintech, and Mr. Keenan described a type of Project Management in an aero engine firm.

Before considering other types of project organisation which can be used by the aircraft manufacturer, I should like to take a broad look at Project Management in relation to an aircraft weapon system required for the British Services. I should like to mention all the agencies involved in achieving the aim of producing an aircraft to meet the specification at the right time and cost since, as Air Cdre. Harland said, what is required is teamwork and mutual confidence between all agencies concerned.

The object of this talk is to give you a situation report on the Concorde flight test programme and to indicate the progress made to date.

Two aircraft have been engaged on the programme so far, the prototypes 001 and 002 (Fig. 1). The French base for Concorde flight test operations is at Toulouse and the British flight test base is at Fairford in Gloucestershire. The two prototypes will be joined in the flight test programme next year by the two pre-production aircraft, 01 and 02.

As is well-known, Concorde is a slender delta wing aircraft and it may be appropriate at this stage to state some of the considerations that led to the choice of this configuration. By virtue of a large root chord, the delta wing can overcome all the disadvantages of lack of structural stiffness and lack of wing volume associated with thin highly swept wings and yet remain aerodynamically thin.