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THE twentieth Salon International de l'Aéronautique was held from June 26 to July 5, the stands being housed in a new permanent building at the south‐eastern extremity of the airport of le Bourget with the outside static aircraft part and runways nearby. Apart from being much more convenient for exhibitors and public, the new arrangement seems to coincide with a resurgence of confidence in the French aircraft industry. A number of interesting new prototypes were shown, and there are now more aircraft for which production orders have been placed, although usually only in moderate quantities.

EACH September the eyes of the aeronautical World turn towards the S.B.A.C. Air Display and Exhibition with interest unequalled by any other event. It is fitting that the Display is now held each year at the airfield of the Royal Aircraft Establishment, one of the world's most prominent aeronautical research centres. This interest becomes increasingly keen too, as the preview day comes closer, because new prototypes of unorthodox designs often appear a short time before the Show to illustrate the results of years of careful planning, development and research of the particular company. These designs often mould the path of progress for smaller countries without the economic resources to forge the way ahead alone. Most British citizens are very proud of their country's place in aviation today, both in the military and civil fields. This is understood by most foreigners because it is clear that Britain has won a place in aeronautical development second to none.

The aim of this paper is to investigate the effect of wing kinematics change on force generation produced by flapping wings.

Forces produced by flapping wings are measured using a load cell and compared for the investigation. The measured forces are validated by estimation using an unsteady blade element theory.

From the measurement and estimation, the authors found that flapping wings produced positive and negative lifts when the wings are attached with the +30° and −30°, respectively.

The authors quantified the characteristics of change in the force generation by flapping wings for three wing kinematics. The wing kinematics was modified by changing the initial wing attachment angle.

The result may be applicable to design of control mechanism for an insect‐mimicking flapping‐wing micro air vehicle, which has only wings without control surfaces at its tail.

The preliminary work may provide an insight for design strategy of flapping‐wing micro air vehicles with compact and handy configurations, because they may perform controlled flight even without control surfaces at their tails.

The work included here is the first attempt to quantify the force generation characteristics for different wing kinematics. The suggested way of wing kinematics change can provide a concept for control mechanism of a flapping‐wing micro air vehicle.

THE change from the parallel wings of the now obsolescent biplane to the tapered wings of the monoplane, usually fitted with flaps, raised a great number of problems, both aerodynamic and structural. Work on these has been pursued vigorously during the past few years, but the designer is still some considerable distance from having all his questions answered. For instance, further information is required as to the relation between wing thickness and profile drag before it can be decided what is the maximum thickness which can be used, taking both aero‐dynamical and structural considerations into account. This question is complicated by the fact that, so far as the tip sections are concerned,. the indications are that the thickness ratio has important effects on the nature of the stall, violent or gentle. So, too, will such factors as centre line camber and position of maximum ordinate affect the nature of the stall in greater or Jess degree. Added to these factors there is, of course, the important one of the taper itself, including—as is now realised—the question as to the way in which the tapering is done, that is, whether by sweeping the trailing edge forward or the leading edge back, or, as is more usual, a combination of the two.

THE purpose of this article is to indicate the developments in aircraft that have appeared since the first post‐war S.B.A.C. Display of 1946. Now is perhaps the time to pause and consider progress in British aviation, particularly as the first turbo‐jet air liner, the Comet, has entered service, the first turbo‐propeller aircraft, the Viscount 700, is being manufactured in quantity, and production orders have been placed for the Hawker Hunter swept‐wing fighter and the Gloster G.A.5 Delta. These aircraft represent a few of the British types evolved in the post‐war period and demonstrate aeronautical advancement.

IT has been found by model tests that the lift of a combination of an aeroplane body and a wing is not in general equal to the sum of the lifts of the two components when tested separately. This difference is broadly referred to as an interference effect. It is dependent on a number of factors which can be generalised into three groups:—

THIS article attempts to summarize the technical development of two‐seater sailplanes during the past thirty years. There is no attempt to contribute anything new to the art, but only to bring together information from various sources. It is also hoped that the data collected will be found useful to designers.

THE authorities of the Institute of the Aeronautical Sciences have decided, so I am instructed, that the Wright Brothers' Lecture should deal with subjects upon which the lecturer is engaged at the time, rather than with a general survey of some wide branch of aeronautical knowledge. This decision has the advantage that the lecturer is actively interested in the subject about which he talks, but it leaves to chance the question whether he is in a position to end his lecture with simple and clear cut conclusions. I mention this because the problem upon which we are working at Cambridge, and about which I shall speak, is not yet solved and my lecture must, perforce, be confined to a discussion of aims and methods and of results so far obtained; it does not contain that simple statement of conclusions which is the ultimate aim of all good research. After this explanation you will not, I hope, be disappointed when the lecture ends on a note of interrogation.

THE main theme of this lecture is the revolution which the high speed digital computing machine is bringing about in the attitude of engineers to structural calculations, and particularly in the attitude of aeronautical engineers to the calculation of the dynamical characteristics of an aeroplane.

THE advantages and disadvantages of the fixed wing for gyroplanes are examined. On the simplest assumptions an expression for the percentage load taken by the fixed wing of a gyroplane is derived. The values so arrived at are compared with those found by experiment and the discrepancy between the two is explained in terms of the increased downwash at the centre of the disc of the gyroplane. It is shown that as much as 50 per cent of the weight of the aircraft can be taken by the wing at top speed with moderate wing area and the most suitable setting. The advantages of an adjustable wing from the point of view of rotor speed control are pointed oat. The Lift/Drag of the combination is raised by 2 over the L/D of the rotor alone. The stability of gyroplanes is discussed.