The main purpose of the investigation has been to clarify the definition of hovercraft wavemaking resistance and to improve understanding of the physical mechanism. The most literal definition of wave resistance as the force which makes the waves is proposed and its practical and theoretical implications are considered. Various interim accounts of this work have already been written, but the time now seems appropriate to assemble and review the overall picture which is emerging.

The pattern of forces on a hovercraft over water is often difficult to analyse because of the complicated interaction between wavemaking, jet air momentum, cushion pressure, wetting and other effects. It is important, however, in making power predictions that the physical interpretation and corresponding scaling laws of the various forces should be understood. A significant feature of the present approach is that a positive and unambiguous basis for identifying the wavemaking force is offered and compared with theoretical predictions. This force, according to the definition proposed, is assured a proper compliance with the physical laws which govern the waves generated and the corresponding scaling and interference effects, which are predicted by theory.

While the subject of this colloquium is limited to reliability, I feel it is essential to put this parameter in its right context as we as users in the RN see it.

We in the RN are most concerned with the availability of our aircraft to perform the required operational task. We define availability as the percentage of a given period of time that an aircraft is either being used or is serviceable ready for use. If availability is low then we need a larger number of aircraft to meet a commitment. With the cost of current aircraft and our restrictions on carrier complements this is a vital consideration.

The technical and the legal aspects of aircraft noise having been adequately covered by others the present paper does not stray unnecessarily into those specialised fields but confines itself largely to the practical aspects of this very wide subject. It examines under six headings what can be done in practice, and covers in some detail what has been done at Heathrow. It describes several of the more interesting arrangements at other international airports, and with reference to the differences between them, poses some questions which must be answered when planning an automatic noise monitoring system. It concludes with reference to some features which, although desirable, may not be practicable for Heathrow.

Before talking about what can be done about noise in the vicinity of an airport it is important to emphasise that worthwhile control can be achieved only as a result of co-operation between the civil aviation and airport authorities, the airlines and the pilots. Such co-operation exists at Heathrow but continuous effort is required to keep it effective.

This paper relates the advantages of centrifugal, mechanically-driven fuel pumps and quotes their ability to operate with hot contaminated fuel. It also shows the substantial weight saving when compared with positive displacement pumps. The poor part load efficiency of the conventional centrifugal pump at its design speed, giving considerable temperature rise in the fuel, has resulted in the development of the vapour core principle where flow regulation is effected by a throttle at the eye of the impeller.

Reference is made to the associated control and distribution equipment which, although not peculiar to the vapour core pump must be made compatible with a pump having an inherent pressure-raising capability which decreases with engine speed. The inlet throttle feature permits adequate control of the temperature rise to be maintained over the whole working range of the gas-turbine fuel systems.

The fundamentals of the pump are explained and the development progress reviewed for application to main and reheat fuel systems. Reference is also made to control methods that are being currently developed for combined engine and reheat systems supplied from a common pump.

The spill nozzle, which was developed specifically for use with hot contaminated fuel, possesses satisfactory characteristics for use with the vapour core pump. The temperature rise data associated with combination of vapour core pump and spill nozzle are quoted, and temperature rise data are also given where the pump is used either for reheat supply or for both combined reheat and main engine fuel systems.

On A recent visit to New Zealand in September 1965, I enjoyed the privilege of attending, as Solicitor to the Society, a meeting of the New Zealand Division Council. Any visitor from the Society to Commonwealth countries is welcomed warmly, and must bring a message from the Old Country. Feeling so remote, they are hungry for any news of any sort. For lack of better material I based my talk to them on my personal association with the Society over the past 45 years.

Such a period of years covers much of the Society's struggle for recognition and retention of its position as the leading technical and scientific Aeronautical body. In this I have been privileged to help.

The Purpose of Army light aircraft, fixed-wing and helicopter, is to help ground units to carry out their normal tactical task more effectively. Therefore the main roles are:

1. Reconnaissance.

2. Fire support.

3. Exercise of command.

4. Tactical movement.

5. Logistic support.

For special-to-arm tasks, light helicopters are integrated into certain major units of the Royal Armoured Corps, Royal Artillery, Royal Engineers, Royal Signals and Infantry. The aircraft must be capable of living in the field and be easy to maintain. Aircraft strengths in these units vary from six in an air squadron of the Royal Armoured Corps, to three in an air platoon in an infantry battalion.

Conventional low-alloy steels at strengths above 100 ton/in2 have been successfully used in various aerospace applications, but laboratory test results, service-performance data and problems in production indicated a need for steels which possessed improved mechanical properties, and which were simpler to machine and fabricate. The 18% Ni-Co-Mo maraging steels were developed in 1961 with the aim of fulfilling this need, and since that date several thousand tons of the steels have been produced and used in all common shapes and forms. In comparison with low-alloy steels of equivalent strength, 18% nickel maraging steels have greater resistance to fracture at highly-stressed notches, defects or cracks, and their susceptibility to hydrogen embrittlement/stress-corrosion failure is generally far superior. The un-notched rotating bend fatigue properties of machined and mar aged specimens of 18% Ni-Co-Mo maraging steels tend to be superior in the low-cycle range and similar in the low-stress range to the properties of low-alloy steels of comparable strength. The fatigue properties of unnotched, in contrast to those of notched, specimens are affected by heat-treatment/machining procedure. Experience gained in production of components has proved that the 18% nickel maraging steels are extremely simple to heat treat, to machine, to cold form and to weld. Exploitation of these advantages can frequently offset the higher initial cost of maraging steel. For example, an analysis of production costs for a complex aircraft component has demonstrated that the use of maraging steel enabled the component to be made by forging and machining at 5-20% lower cost than with a conventional low-alloy steel, despite the fact that initial material costs were five times greater. 18% Ni-Co-Mo maraging steels retain high strength at temperatures up to 350-400°C, and have given good service in short-duration heating cycles at much higher temperatures. Maraging steels may be surface hardened by various methods, and gears and dies treated by simultaneous nitriding and maraging have given excellent performance.

The tremendous technological efforts which have been made in the past five years have yielded the majority of data and experience necessary to ensure successful use of the 18% Ni-Co-Mo maraging steels in the aerospace industry.

The twenty-first British Commonwealth Lecture, “Private Enterprise in British Air Transport”, was given before the Society by F. A. Laker, ARAeS, on 14th October 1965 in the Lecture Theatre, 4 Hamilton Place, London W.1. The Chair was taken by the President, Sir George Gardner, KBE, CB, HonDSc, BSc, HonFRAeS. Introducing the Lecturer, Sir George said that after a brief start in automobile engineering, Mr. Laker had switched in 1938 to aircraft—with Short Brothers. He thought that Mr. Laker really came into prominence in 1947 when he formed Aviation Traders Ltd, and not long afterwards Air Charter Ltd, which later merged with the Airwork Group. Mr. Laker had kept on expanding his interests and formed British United Airways of which, as they knew, he was Managing Director. Mr. Laker was a qualified pilot, as well as an engineer and flew his own Cessna aircraft round the various bases of his organisation. He was also President of the Society of Licensed Aircraft Engineers and Technologists.

When one talks of the difficulties of the aerospace industry in this country, it is all too easy to point a finger westwards to the United States. It then seems right to talk of long production runs and large home markets. One can then turn to our own industry and to its output since the last War, and perhaps forgive.

But should we?

In this short paper, a young author intends to examine professional education and manpower in aeronautics, because herein must be the reason for any future success or failure of the products of the industry, and the pointer to the future level of expertise in the art.

The technical features of the data acquisition system used in Blue Streak flight trials are summarised briefly. The results obtained from this system, and the design modifications to which they have led, are then discussed under the heading of performance, control, structure and environment and propulsion and pressurisation.

While not of the same venerable age as the Royal Aeronautical Society, the Royal Aero Club can lay claim to a respectable antiquity having celebrated its golden jubilee on 24th September 1961. Registered on 29th October 1901, the Aero Club antedated a potential rival by two days. As it was by a very short time the earliest, so for many years it continued the only, authority on the practice of the art of flying, and still reigns supreme in many aspects of sporting and private aviation.

While many of the detailed aspects of the work grew inevitably, over the years, into separate sports with their own organisations, affiliated to the parent Club, the basic responsibilities of looking after the interests and promoting the well-being of private flying in this country have never left us.

Since some aspect of fluid dynamics is involved in the design or operation of many items of plant in the electrical supply industry, this survey is confined to those items which are peculiar to the industry and whose performances are directly related to their aerodynamic behaviour. Three main problems will be discussed namely, the internal flows in boilers and natural draught cooling towers and the aerodynamic behaviour of overhead lines. In addition, the aerodynamic aspects of current and recently initiated field experiments will be considered.

Half a year has passed since the major airlines of the world, in a burst of energy, rallied round to “save” the Warsaw Convention. The Convention had as its principal effect a limitation of $8300 (not quite £3000) on liability of air carriers to international passengers for death or injury, and the United States had given formal notice that it could no longer accept this. The effort to update the Warsaw Convention of 1929 had, essentially, failed so far as the United States was concerned, in that the revision proposed at the Hague Conference in 1955 was only double, the Warsaw limit—$16 600 or £6000— still far below an acceptable ceiling on recoveries for accidental death caused by common carriers. The United States Senate had not ratified the Hague Protocol, it clearly was not going to, and all attempts by the United States Executive Branch to supplement the Warsaw/Hague limits—such as by compulsory trip insurance or voluntary waiver of limits by the carrier—had come to naught.

The first serious attempt at refuelling in flight was made in the USA in 1923 under the direction of Major (later General) H. H. Arnold, in which two aircraft were equipped as tankers, each with a 50 ft length of hose, and a flight of 37 hr 15 min was achieved. Towards the end of that year the first serious attempt in Europe was made in France.

There was then a lull until January 1929 when the US War Department sponsored some duration flights, the best known being that by the Fokker “Question Mark” under the command of Major (later General) Carl Spaatz which remained airborne for 150 hours. This flight was followed by a spate of US commercial pilots’ attempts until in 1930 the endurance record stood at 647½ hr. Most of these flights in themselves were of little practical value but they aroused the interest of Sqn. Ldr. (later Air Marshal Sir Richard) R. L. R. Atcherley, RAF while taking part in the National Air Races in the USA in 1930. On his return to Transjordan, where he was stationed, he set to work devising an improved method of contact, the results of which were patented. He also planned to demonstrate his new method with an attempt on the duration record but was refused permission by the Air Ministry.

As I come to the end of five years’ training as an Aeronautical Engineer, several thoughts come to mind, both about my training up to the present time and the future of the aerospace industry in which I am about to serve.

During the past ten years, the aerospace industry has seen many changes, not only in the form of amalgamations and project cancellations, but also in the way it must face the future. More recently it has seen the publication of the Plowden Report with all its implications. Although for many the future paints a gloomy picture, at no time has the thought of leaving the world of aeronautics been farther from my mind than it is now.

Mr. Haynes in his contribution to the Symposium, and also in previously published papers, has very adequately described the general development, advantages and characteristics of the maraging steels. However, as much of the information which he has given relates to the work done in the laboratories of International Nickel, and because we have only been able to find relatively little information available relating to production experience, we at Dowty Rotol set out to investigate the problems of steel making, forging, and resultant mechanical properties to be obtained under more normal production conditions. As landing gear manufacturers, our prime interest lies in the production of relatively large forgings of somewhat complex shape, and we were therefore particularly anxious to investigate first of all that our normal steel suppliers could produce material to the correct composition, that the material would forge as easily as conventional material, and that the subsequent forgings possessed adequate trans-verse properties, particularly insofar as ductility is concerned. In this latter connection, we had heard of certain difficulties encountered in the USA relating to inadequate ductility in large forgings, which they had concluded was related to the carbon and sulphur content of the steel: i.e. that it was essential to eliminate brittle intermetallic compounds such as titanium carbo-nitrides and titanium sulphides from the steel.