The spin is a mode of motion of which we know very little. The general public are inclined to look upon it as necessarily dangerous, but this we do know it is not. It is only in rare circumstances and under fortunately rare conditions that danger arises. Nevertheless there is ample warrant for its study, and for that study to be treated as one of high importance. New conditions of aeroplane operation are continually arising, the very increase of speed itself would ensure an entry into regions never before penetrated. Hence it is ever necessary to seek for remedies even before serious difficulty has arisen; this anticipating action always seems to me to be absolutely essential, and I am comforted by support in this view from no less an authority than Francis Bacon, who, in his essay “ On Innovations,” wrote: “ Time is the greatest innovator; and if time in course alters things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?”

With the present-day normal type of wing the spars are the principal members, and I propose to start by tracing very briefly the evolution of the spars which are used in the Wapiti wings to-day.

The personnel of the Steel Wing Company have been designing and making spars ever since 1912. I shall start from the time when we first began to use what might be described as the box type of spar, which was composed of four strip steel sections.

The first spar that we made of the box type had channel webs with flat flanges, which had only shallow corrugations, and the rivetted joint was flat. This spar was not very efficient in steel, so we deepened the corrugations and curved the rivetted joint, and this gave a better result.

To attempt to discuss aerodynamic theory in a single lecture is perhaps a rather rash undertaking, for the subject is so vast that a proper discussion would require a volume, or even a series of volumes. My object, however, is not to cover the whole field of aerodynamic theory with its manifold applications to aeronautical engineering, but rather to discuss some of the fundamental conceptions on which the theory rests, and to discover where theory can be helpful and where it is necessary to rely wholly on experimental results.

During the early stages of the development of aircraft in the pre-war days it was realised that wireless communication would provide the only satisfactory means of maintaining contact between an aeroplane and the ground. Although the technique of wireless was in its infancy at the time, it must be remembered that the needs of aviation in this respect were correspondingly limited; pilots of early types of aircraft had their time fully occupied in keeping their machines in the air at all, and had no energy to spare for communicating with persons on the ground.

The problem of keeping pilots and observers warm when flying at high altitudes was brought into prominence during the late war. At a height of 20,000 feet the normal temperature is approximately − 25°C. or “45° of frost,” Whilst in winter at an altitude of 30,000 feet temperatures of the order of − 5o°C. or “90° of frost” are frequently encountered. When flying at probably 100 miles per hour in temperatures of this order, all ordinary means of keeping the body warm are quite inadequate and no padding or lagging capable of being worn as a suit will keep the body warm for more than a few minutes.

In the following article an attempt has been made to present the characteristics of a sail by considering it as an aerofoil, the “ lift ” and “ drag ” being replaced by two forces mutually at right-angles in a horizontal plane, one force corresponding to the drag, acting in the same direction as the relative wind. It appears that skill in the art of sailing could be reduced, apart from other considerations, to ability to set the sail in the required position determined by its aerodynamic characteristics.

The lecturer adopted the course of explaining the Cold Working of Metals from first stages.

The lecturer first dealt with the cold raising of metals and pointed out that in this case the operator always worked from the outside, and to avoid “ puckering ” of the metal it was gradually hammered concentrically so that “ puckers ” were eliminated almost as soon as they appeared.

The spinning of metals was then dealt with and nearly all cylindrical objects are worked in this way. Commencing as a metal disc the object is placed on a lathe and backed up on to a wooden former block and gradually formed on to the block. By eliminating the sudden bending of the metal round the sides of the block the “ puckers ” are reduced to a minimum and the metal is allowed to “ flow.”

The trade was only just emerging from the stage when aero wheel brakes were merely adapted forms of automobile wheel brakes, and the aeroplane industry from the point of view of wheel brakes is now in about the same stage as the motor industry was with car brakes six years ago. In this respect the United States is very far ahead of us.

The aircraft industry is now realising, however, that the brake needs of an aeroplane have to be specially catered for, and it is to this end that research is being made, the ordinary motor car two-shoe brake being abandoned as inefficient.

The lecturer stated that the average reduction in the landing run of machines fitted with the modern Bendix-Perrot brake was 50 per cent., and that the fitting of brakes has the effect of assisting Ground Crew.

The development of racing seaplanes has been so very rapid in the last few years that all other means of locomotion has been left a long way behind. Over 350 miles per hour has been reached in level flight by a machine controlled by a human being with a fair amount of ease and in comparative safety. A skilled human being it is true, but all advanced science requires skilled control.