This is the first meeting at which it has been possible to talk openly about transonic tunnels with ventilated working sections. Many already knew that a large number of tunnels, particularly in the U.S.A. and this country are being built or modified with slotted or perforated working sections. Up to quite recently, however, security considerations have shrouded this work but it is now possible to draw the curtain.

The forces due to normal pressure have been measured in the region of the junction between a rear-loaded wing swept forward at 28°, and a flat plate on which a turbulent boundary layer had developed. The Reynolds number was 1·03 × 106, based on the streamwise wing-chord of 500 mm. At low incidences, 0° < α ≤ 6°, the local pressure drag coefficients were found to be negativeaway from the junction, and the interaction with the junction was found to be favourable;that is the pressure drag coefficient became more negative as the junction was approached. At α = −3° the pressure drag coefficient changed from a positive value away from the junction to a negative value close to the plate. These results contrast with those for a swept-back wing-plate interaction, which has been reported as being unfavourable so far as the pressure drag was concerned. At 6° incidence, the interaction remained favourable but there was evidence of root stall beginning. At an incidence of 9°, root stall was much more marked and the positive pressure drag coefficient increased as the junction was approached.

The effect of backlash and trailing-edge strips on the flutter speed of a two-dimensional model of a tailplane with tab has been investigated in a series of wind tunnel tests. When backlash is present, a change in preload, which is achieved by varying the incidence of the tab, can dramatically alter the flutter speed. The addition of trailing-edge strips to the tab lowered the flutter speed.

The following extremely important table, compiled by Major Linton Hope, was inadvertently omitted from the reprint of his lecture in the August issue of the Journal. It should also be noted that the last set of Flying Boat lines, on page 470, is the design which Major Linton Hope made in 1916, after the trials of the 41ft. design, Fig. 2, and to which he refers in his reply to Mr. Baker. It should be noted that the angles of the step tangents to the foreplaning bottom have been increased and the back step reduced in size and moved aft, both of which features appear in C.E.I. designed some considerable time afterwards.

The CHAIRMAN, in introducing the Author, said that Mr VENNING had spent from 1941 to 1946 in the Royal Signals on mobile communications and from 1946 to 1949 at the City and Guilds Engineering College From 1949 to 1952 he had been in the Royal Naval Scientific Service, working on underwater acoustics From 1952 to 1955 Mr Venning had been at the College of Technology, University of Manchester, as a Lecturer in Electrical Engineering In 1955 he joined the University of Southampton in the Department of Electronics where, in addition to lecturing in electronics he was undertaking a research contract for the Ministry of Supply basically on the subject of his present paper

A Fire Prevention Sub-Committee of the Aeronautical Research Council published its findings in 1922. At that time the major risk was from crash fires in which the fuel was ignited by the engine either directly or indirectly through the medium of oil, wood, fabric or dry grass. Preventive measures recommended included crash-proof tanks, with a suggestion that these should be carried on the wings; fire-proof bulkheads; fire-proofing of inflammable materials; cooling of exhaust pipes; and fire-proofing of magnetos. Fires in flight were usually in the carburettor and a successful carbon tetrachloride extinguisher was designed at the Royal Aircraft Establishment and tested in flight by the late Squadron Leader Norman. However, the weight of the system, about 35 lb. per engine, was considered excessive and the action recommended was to turn off the fuel and dive the aeroplane.

Bragg, in ref. 1, gives a theoretical treatment for the variation of the discharge coefficient in compressible flow of any shaped nozzle with applied pressure ratio given one set of values. This shows that the discharge coefficient of any nozzle with a value less than unity at a pressure ratio approaching unity, rises continuously as the pressure ratio increases and reaches the maximum at a pressure ratio of infinity (zero back pressure). This is based on the assumption that the flow conditions at the Vena contracta are uniform and at unity Mach number once the applied pressure ratio is equal to/ or above the critical (sonic) value.

The Aerodrome, as the point of contact between the aircraft and the world of reality, has to a large extent been taken for granted. The designer regards it as the base for prototype tests and the airline operator as his aerial railway station. It is my intention to show that aerodrome development is at a critical stage of evolution on this side of the Atlantic, that many of the related problems do concern the aircraft designer and operator, and that if these problems are not given consideration, difficulties will be encountered in civil operations.

To quote an example; the optimum aircraft type to serve a system of air routes can be worked out taking into consideration the range required, payload and speed, but if the aircraft ultimately ordered and produced cannot safely operate from the aerodromes to be served because of the runway length and approaches, then the operations will either have to be reorganised or continued without due regard for safety.

The Chairman, in opening the meeting, said that it was a pleasure to welcome at that meeting of the Association a distinguished engineer from France, Monsieur Rene Dorand, who was well known internationally as a pioneer of the helicopter M Dorand’s name became associated with that of Louis Breguet in 1931 when they built in collaboration a helicopter with co-axial rotors That machine had achieved considerable success both in hovering and in forward flight It established international records for a flight duration of more than one hour and a forward speed of more than 100 k p h, and it also demonstrated an autorotative descent from 100 meters

M Dorand became a graduate engineer in 1921, and in the same year took a diploma in electrical engineering He then joined the Louis Breguet Aircraft Company as a graduate engineer and became Technical Director of the Breguet-Dorand Helicopter development group

This is a great occasion; I feel quite unworthy to do justice to this commemoration of a great man and a revolutionary event and to become one of the illustrious band who have so graced this occasion in the past. For the more one reads about the Wrights' achievements, the more one is impressed by them as men of stature—of great character, determination and intellectual strength with a most endearing modesty. They had too, such a sense of fun and there is a golden thread of family affection running all through the record. They were men of vocation just as their father, Bishop Milton Wright, and there is no doubt of the influence of the family ties on what they did. One senses how much home meant to them and how much they all turned to Katharine, the womanly stabilising element. A comment of Wilbur's in one of his letters to George Spratt commenting on a technical argument they had been having, is very revealing. "It is a characteristic of all our family to be able to see the weak points of anything", a vivid hint of most lively family discussions, and of course, this most rare combination of brothers must have been a fundamental element in all their work.

The problems involved in the packaging of Service radar equipment are reviewed. Information on shock testing techniques, instrumentation and a design procedure for cushioning are given, together with some examples of current packaging methods used by the Ministry of Supply's Radar Research Establishment, Malvern, Worcs. The paper is based on a lecture given to the Royal Aeronautical Society, Gloucester and Cheltenham Branch in December 1954. Received October 1956.

This paper assesses the application of a new method for system stability analysis, the weight functions method, to the longitudinal and lateral motions of a High Incidence Research Aircraft Model. The method consists of finding the number of weight functions that is equal to the number of differential equations required for system modelling. The aircraft’s stability is determined from the sign of the total weight function; which should be negative for a stable model. The Aero-Data Model In Research Environment (ADMIRE) simulation, developed by the Swedish Defence Research Agency, was used for the aerodynamic aircraft modelling, with the following configurations: Mach number = 0·25, altitude = 500m, angle-of-attack [–10 to 30]°, elevon deflection angle [–30 to 30]°, canard deflection [0° and 25°] and rudder deflection angles [–30° and 30°]. These flight configurations were selected because they are among the flight conditions for Cat. II Pilot Induced Oscillation (PIO) criteria validation, performed on the FOI aircraft model presented in the PIO Handbook by the Group for Aeronautical Research and Technology in Europe, Flight Mechanics/Action Group 12. This aircraft model has a known instability for longitudinal and lateral motions and so a control law was introduced to stabilise its flight.

Simple Formulae are presented for the first three bending-type and the first torsion-type natural frequencies of any constant thickness cantilever triangular plate. The formulae are derived by a semi-empirical method. Comparison of calculated frequencies with test values indicates agreement within a few per cent. for a variety of plate plan forms.