In control theory, stability is investigated by established techniques such as the root-locus method. The same techniques may be applied to the control equivalent of a mechanical system and will show the transient state of the system. Vector methods such as are used to solve vibration problems may also be extended to give transients.

This note gives a vector representation of the transient vibration of a one degree of freedom system possessing inertia, elasticity and viscous damping. For the transient which is set up by a change in the steady vibration of the system, the initial amplitude and phase angle are readily found by vector methods. This information is sufficient to define the transient.

The Title of this paper presupposes the existence of the most important and fundamental document, namely a clear specification of design requirements.

The normal sequence of activities after receipt of the specification is as follows: —

1. Design.

2. Prototype and Experimental batch manufacture.

3. Development (and Approval Testing).

4. Production.

5. Customers’ Use.

The function of Design and Development determines the ability of the design to meet the specification, and this can be classified as the “Quality of Design.”

From June 1937, I had been working on advanced project design schemes with a small group located at the Rolls-Royce guest house. An ideal spot for quiet concentration, in extensive private grounds by the river Derwent and on the outskirts of the village of Duffield.

Early in 1939, we were informed that Dr. A. A. Griffith would be occupying a room at the guest house. E. W. Hives (later Lord Hives) had invited Griffith to join Rolls-Royce and to work on the initiation of aero engine research, in particular the gas turbine and its applications.

We were naturally interested to learn more about him but all that I could gather from my associates was that he was “tall, thin and had a hell of a brain”.

The Royal Aeronautical Society may well be considered as one of the more important founders of the science and practice of aeronautics, bearing in mind at the same time the work of Sir George Cayley. Other early claimants in the history of aeronautics are the Royal Aero Club on the sporting side and the Royal Aircraft Establishment, the latter known formerly as the Balloon Factory. These date back many years but so also does the Aeronautical Research Council (ARC), originally called the Advisory Committee for Aeronautics (ACA), which although not so old as the other bodies mentioned above, has had an unbroken history of some fifty-seven years.

Until the middle of this century farmers had been benefiting from New Zealand's 31 million acres of pastureland without applying any fertiliser to the soil.

During 1948-49 the Government realised the urgent requirement for aerial fertilising to restore this soil to its correct chemical balance and the Royal New Zealand Air Force was made responsible for research, and extensive fertilising was undertaken with large aircraft, such as the DC-3. The work was charged for on a “county” basis and thus the cost was eased by the local rates.

I have always been an enthusiast for engines, even before 1913 when after a flight with Geoffrey de Havilland in a BE2a, I took my ticket in a Caudron biplane at Hendon, enjoying a little thrust, and much castor oil from the “Y” Anzani engine. When I completed my figure of eight, nose well down on the turns, the only engine control—the switch—failed, so I foreshadowed my technical future by kicking off the petrol tap! Before that I Was acquainted with engines in the motor trade. I was mechanic in the Maudslay car in the first Tourist Trophy Race of 1905; our engine ran well till it became a bit short of petrol and ate its butterfly throttle. But, in 1907, I drove their first live axle car in the Scottish Reliability Trials, obtaining a gold medal for a non-stop run.

This note outlines a method for the prediction of drag due to lift of plane wings at Mach numbers below drag divergence and Reynolds numbers above 106. The method is based on the correlation of a number of wind tunnel measurements in terms of the effect of viscosity on lift curve slope. A comparison is made of the accuracy of estimating the induced drag factor, k, using this method, with the method of ret. 1, and it is shown that considerable improvement has been made, and that, in general, the predicted value of k is within 10% of experiment.

In 1909, Sir Richard Glazebrook (then Dr.) was Director of the National Physical Laboratory and under him the Superintendent of the Engineering Division was Sir Thomas Stanton (then Dr.). These two scientists were responsible for initiating aeronautical research at the NPL. The main stimulus came, however, from the Advisory Committee for Aeronautics, formed in May 1909 with Lord Rayleigh as President and Glazebrook as Chairman. This committee obtained a grant from the Treasury for aeronautical work amounting to £1923 13s 5d for the seven months of that year, with a grant at the same rate for the year 1910; this money was spent at the NPL.

Ever since the realisation of the matrix Displacement Method, the introduction of a kinematically satisfactory spar element has remained a difficult and, as yet, not fully resolved problem. Two cardinal points have to be considered in establishing a suitable spar model: first, it must reproduce adequately both shearing and bending deformations, and second, it must satisfy everywhere the kinematic compatibility conditions, especially at the junction with the wing cover. Of course, if we were to restrict ourselves to a uniform rectangular element, the corresponding theory could be written down in a few lines. However, from the practical point of view, it is essential to take account, ab initio, of taper, and this necessitates some subtle considerations, especially if we have to allow for asymmetrical taper, as becomes indispensable with some modern flying vehicles.