Beryllium is a metal possessing some attractive properties for aerospace applications, but its advantages are offset by the present inability to achieve acceptable isotropic ductility, by the high cost of the fabricated metal and by the special health precautions required for workshop treatments and handling.

Considerable research and development have been applied to the technology of beryllium during the past decade and comprehensive data are available in books and the proceedings of international conferences held in London, Gatlinburg, Philadelphia and Grenoble. Outstanding among the various problems discussed have been modes of deformation and fracture, the efficiency of various methods of purification and the influence of increased purification on the behaviour of the metal.

What I talk about relates to an experience on military aircraft produced for our own Services under the working arrangements which were then usual.

We have heard that the Services are finding that unreliability is taking too much of their time and money and could impair their fighting efficiency. I think that this situation is well understood by aircraft constructors, and that there is a real desire to improve the situation and to do whatever can usefully be done. But it is not easy to quantify the subject of reliability, and some of the approaches which have been suggested for improving reliability do not seem feasible to me.

The past decade has seen considerable advance in the production of cotton from Rhodesia and the adjacent former Federation territories of Malawi and Zambia, brought about very largely by the introduction of effective pest control measures originating from the work of the Cotton Pest Research Scheme, located at Gatooma, Rhodesia.

Complementary to a work programme investigating the type and formulation of insecticides capable of controlling an insect pest complex including bollworms, jassids, aphids and stainers, attention has been given to the design of spray equipment suited to both extensive European and intensive African forms of cultivation. The “tailboom” modification to the conventional knapsack sprayer has been developed and this versatile piece of equipment in several mechanised guises forms the basis of the recommended ground spray machinery.

In my boyhood days I well remember seeing balloon ascents at the Crystal Palace, which sowed the seed for my ideas of man being supported and carried in the air. Many times, when flying my kite, it passed through my mind that if, instead of holding it against the wind to keep it in an elevated position, the kite would rise and keep elevated if it were moved through the air at a speed equal to that of the wind, but this boyish reasoning into matters of heavier-than-air flying machines remained dormant while I carried on with my general engineering training.

Between the years 1905 and 1910, I took serious notice of the experiments made with gliders, particularly those by Wilbur and Orville Wright. Thus, my interest in aviation was revived, and with the experiments with engine-powered gliders, and the very early flying machines, I definitely decided that Aviation was to be my future occupation.

Most teachers of gasdynamics with whom the writer has discussed the Prandtl-Meyer analysis find difficulty in giving a lucid exposition to students; the standard treatment tends to be long, and mathematical rather than physical, so that steps in the process of integration are difficult to remember. Lockwood Taylor gives a short treatment; but he begins from Ackeret's formula, which is in effect the differential equation to be treated; and he avoids the actual integration. These considerations have prompted the writer to publish the following treatment, which though self-contained is quite short, and—being mostly graphical—gives some insight into the physics of the problem.

Apart from Royal patronage and the manifest concern with aviation, it must seem to many people that there is little in common between the Royal Aeronautical Society and the Royal Aircraft Establishment. Yet research into the lesser known activities of the early RAE has revealed not only a comparable antiquity but also a remarkable similarity in the early history of the two bodies. Both had to fight hard to stay alive, and often continuing existence depended upon a tenuous thread liable to snap at any moment.

In its early years the Society was essentially a group of dilettante with all the advantages as well as the disadvantages that this entails.

In recent years the use of turbine flowmeters in industry has become well established. An NEL publication by Myles and Harrison gives an excellent survey of their construction, use and calibration. It seems from ref. 1 that calibration by the manufacturers is done mainly with liquids, presumably in order to use a weighing technique to obtain the volume flow. A typical calibration report for a gas is that of Redding where the flowmeter in question was calibrated on air against a vena contracta tapped orifice. Eight experimental points are given on this calibration curve over the range of the meter. It was considered of interest to calibrate a turbine flowmeter on air against a pitot tube traverse. This method is generally regarded as being of greater accuracy than an orifice or nozzle method. Also it was considered that if a large number of readings were taken the amount of random scatter, if any, would become apparent.

My interest in Aviation first developed in 1914 when I was living in Frankfurt opposite the aerodrome learning German. I often witnessed the landings of the German Zeppelin airship, the “Viktoria Louise”, which used to return there from numerous commercial flights throughout Germany. Even in those days sightseers could journey up and down the Rhine in this stately airship, in which every comfort was provided, including a first class dining saloon.

The day before war was declared I returned home and joined the Royal Naval Air Service and was eventually commissioned as Flight Sub-Lieutenant in October 1915. I was posted to the Airship Section which had recently been taken over from the Army by the Royal Navy to work in conjunction with destroyers in submarine spotting.

For the analysis of sandwich panels it is necessary to know the shear and flexural properties of the sandwich. For some of the more common sandwich constructions theoretical solutions exist. However, in the majority of cases, it is necessary to determine these properties experimentally. This note, based on work done for the Royal Aeronautical Society's Structures Committee in which the major British aircraft companies interested in this subject were consulted, describes and evaluates the various test methods commonly in use. Particular reference to the accuracy of results obtained and to the relative economics of the test methods is made.

Previous speakers have referred to the subcontractors being responsible for most unreliability. I feel therefore I must begin by pointing out that the electronics manufacturer merely designs equipment and assembles components from sub-contractors. Nevertheless we do take the responsibility for our products.

In the post-war period there have been continuous and rapid advances in the design of aircraft. To take full advantage of the higher performance and increasing speeds offered to them, the airlines of the world have demanded smaller and lighter electronic equipment providing, at the same time, more and more facilities. The rapid increase in traffic, the higher speeds of aircraft operation and the introduction of pilot-controlled communications have demanded more complex equipment and the electronics industry has met these requirements by continuous development of both components and equipment. It is a tribute to the industry that the present day equipments, although vastly more complex, are smaller, lighter and no less reliable than their counterparts of ten years ago.

Two recent papers by Bradshaw have drawn attention to instabilities in the flow through wind tunnel screens. In Plate 1 of ref. 2 a smoke tunnel photograph shows the manner in which the jets coalesce behind a high blockage, two-dimensional cascade. In the present note, three points relating to this flow will be discussed.

My First attention to matters Aeronautical occurred at about the turn of the Century, when a balloon appeared over an open space at the north of Portsmouth and a parachutist came down therefrom.

Again, I remember seeing an inflated non-rigid airship exhibited in the Victoria Hall, Southsea, made by a man named Spencer.

One recollects, also, that in those pre-motoring days, it was not unusual for errand boys, on their way in the streets, to sing some music-hall ditty.

The first well-formulated scheme for lighter-than-air transport was put forward by Francesco de Lana-Terzi in a scientific treatise in 1670. He visualised a craft made lighter than air by evacuating the air from within it, and conducted the first accurate experiments to determine the density of air, which he found to be 1/640th that of water. It comes to most of us today as surprisingly relevant to recall why he did not carry his idea into practice: he was a Jesuit priest and wrote, in the words of Robert Hooke's translation, “God would not suffer such an invention to take effect, by reason of the disturbance it would cause to the civil government of men. For who sees not that no city can be secure against attack …“.

The crops of every continent of the world have been devastated from time to time by locusts or grasshoppers. To mention three major locust species, the Desert Locust (Schistocerca gregaria Forsk.) has caused havoc in a broad band of the world stretching from East Pakistan to Senegal and from the Mediterranean to Central Africa, the Red Locust (Nomadacris septemfasciata Serv.) has infested East, Central and Southern Africa, and the African Migratory Locust (Locusta migratoria migratorioides Rch. and Frm.) has plagued most of Africa south of the Sahara.

What happens in one part of a plague area can significantly affect the situation in others and locust control is therefore an international problem, requiring international co-operation. Many of the threatened areas are countries where standards of living are not high and local agriculture is a mainstay of the economy; the regions are often inhospitable and lack modern roads, aerodromes and lines of communication.

Towards the end of the days of the Royal Naval Service, 1919, I was posted to Barlow, where HMR33 was under construction. Barlow was in Yorkshire, near Selby. I knew where Selby was, as a Sunderland man. Selby was “way down south, near York”.

Barlow must have been the best RNAS station to be posted to, just a small group of officers and ratings, the potential crew of the wonderful new airship HMR33.

When we arrived, the “ship” was about half to three-quarters built, and, among other things, our duties were to make ourselves useful and get to know the construction of the whole airship. We took a great interest in our official duties, but some, I believe, were also interested in the girls working on the ship, which, after all, added a bit of romance, especially to an RNAS station.

In preparation for the wind tunnel testing of a series of aerodynamic research models a strain-gauged balance was sought which could be successfully made without the use of sophisticated tools. The principal requirements which influenced the design of the balance were:

1. (a) It must enable lift, drag and pitching moment to be measured.

2. (b) Deformation of the balance under the aerodynamic loads to be small.

3. (c) Use of only basic workshop tools.

4. (d) Short manufacturing time.

Further, the models were to be sting mounted at one end of the balance with their span vertical. The other end of the balance was to be rigidly fixed to a supporting stand which would be mounted on the wind tunnel turntable to permit incidence variation (Fig. 5).