Recent research into the fluid mechanics of hitting objects with air jets to eject unacceptable ones from a line of such particles in flight has shown the need for a better method of predicting the drag force involved since this is also the deflecting force in such an application. In most cases, the transverse dimensions of the jet are similar to, or smaller than, those of the target body so a drag force estimate based on infinite flow is likely to be seriously in error. Corrections are therefore needed to allow for jet diameters ranging from a fraction of the object’s size to many times that size. Achenbach investigated the blockage corrections for spheres in a closed circular wind tunnel but to the best of the authors’ knowledge no such results have been available for spheres in open jets, where the correction will in any case be of opposite sign.

In Switzerland aircraft often have to take off and land in narrow mountain valleys where a strong, irregular wind is blowing. In these circumstances one faulty casting may cause failure of a control; or a small part, if insufficiently heat-treated, may fracture and result in the loss of the aircraft. For this reason, thorough inspection during production and careful maintenance of the aircraft are of prime importance. Control within the aircraft factory consists of inspection of the raw materials, such as bars, sheet metal, tubes, castings, forgings and so on; testing of the most important parts during manufacture to detect cracks and to control the heat treatment; and the final control of all parts, of components and of the whole aircraft. Maintenance inspection reveals cracks, corrosion and other defects of the most important parts of the aircraft.

The Coefficient of contraction of a jet of fluid flowing through an orifice has been widely studied in the field of hydraulics, using a jet of water discharging through an orifice into the atmosphere and measuring the area of the jet at the vena contracta. the coefficient of contraction cr is then defined as:

As in many other branches of engineering, progress in propulsion controls has, for the past 30 years, meant the increasing application of electronics.

Throughout this period, the whole Aero-Engine Industry has used electronics to perform various limiting functions, particularly in the form of jet-pipe temperature limiters. However, Rolls-Royce and the British Controls Industry are undoubtedly the pioneers in the radical application of electronic technology to the control of aero gas turbines. World-wide, there are still only two aero engines in civil operation today with ‘Full-Authority’ electronic controls. They are:

The Rolls-Royce Proteus turboprop which has accumulated seven million hours in the Britannia since its entry into service in 1957. Its pre-transistor Ultra system still uses magnetic amplifiers and has achieved a very high reliability indeed, (in-flight shut-down rate = four per million engine hours).

There are a number of essential differences between aircraft designed to operate from carriers and those designed to operate solely from land bases. Some of the features are detrimental to good structural weight and even to aerodynamic performance, and involve both the aircraft and carrier in special equipment.

Of these features the two most important are assisted take–off and deck landing. Assisted take–off includes catapulting, accelerating and rocket assistance; landing involves arresting and safety–barriers.

It is now the practice to refer to all methods of mechanically–assisted take–off as catapulting, to bring it into line with American terminology. Until recently, catapulting denoted a particular method of launching whereby the aircraft was supported entirely on a cradle with no part of the airframe in contact with the ship structure, and such equipment was installed in ships with no flight deck. Accelerating denoted that the aircraft was launched along the deck on its own undercarriage which gave it some degree of support. Accelerating was peculiar to ships with flight decks, i.e. carriers.

The conventional landing technique for most aircraft involves a constant speed approach along a well denned glidepath. The speed is selected to maintain an adequate margin above the stall. Allowance is made for wind conditions. At the beginning of the landing approach a pilot is quoted a nominal mean surface windspeed and direction by radio contact with the airfield control tower. The local controller is provided with a conventional meteorological office dial-reading anemometer but, because of other duties, does not monitor it continuously.

For centuries, scientists and engineers dreamed of going to the moon or the planets, but the more they learned about the problems involved, the more improbable space flight appeared.

While there were many difficult questions, the principal problem overshadowing all others was how to propel the vehicle free of the earth's gravitation.

When serious attention finally was devoted to the magnitude of the thrust required and the means for obtaining it, space flight became a real possibility. This assurance of adequate propulsion marked the true beginning of the space age, and continues to be the prerequisite for the more ambitious space flights planned for the future.

The aerodynamic energy method provides a means of flutter-suppression control-law design based wholly on oscillatory aerodynamic forces on a notional structure with notional normal vibration modes. The method has been proposed as a means of flutter suppression regardless of structural considerations, other than those mentioned. As originally conceived, the method is based upon the assumption of totally irreversible active controls. In this paper, the effects of finite impedance of actuators on the implementation of the method are investigated analytically. The conclusions do not augur well for the method.

Wing Commander BRIE said that Mr BRISTOW had been connected with many aspects of helicopter development for a number of years He first learned to fly helicopters in 1944 at Floyd Bennett Field, U S A, and in 1946 was a helicopter test pilot with Westland Aircraft Ltd In 1948 he received the Royal Aero Club Silver Medal for the relief of the Wolf Rock Lighthouse, and in 1949 the Croix de Guerre for jungle rescue in Indo China whilst he was Technical Manager and Chief Pilot with Hehcop-Air, Pans In 1950 he formed his own company, Air Whaling Ltd and pioneered the use of the helicopter for whaling m the Antarctic In 1955 he formed Bnstow Helicopters Ltd , and tonight we are to hear an account of the work being done by this Company in the Persian Gulf and the large part the helicopter plays in transporting men and materials from the mainland to the drilling rig fifty miles out in the Gulf

Loads have been measured on wedges placed symmetrically in supersonic jets of air. The jets were created by a nozzle with a radially divergent exit section having a lip Mach number of 2.2. The underexpansion ratio was varied from 1 to 2.2 and the distance between the nozzle exit section and the wedge apex was varied from 0 to 2 nozzle exit diameters. All wedges had a base width equal to the nozzle exit diameter: their total included apex angles covered the range 30° to 180°. Pressures were measured on the front faces and the bases for three of the wedges, hence enabling individual contributions to the overall force to be evaluated. Overall loads were measured by means of strain-gauged supports for all six wedges. It was found that the overall load coefficient is only weakly dependent on underexpansion ratio and wedge location but depends strongly on wedge angle. The maximum load coefficient recorded corresponded to 73% of the jet momentum. The base pressures contribute up to 59% of the overall load on a 45° wedge but rather less for larger wedge angles.

When your Secretary, shortly before Easter, wrote to ask me to give the Wilbur Wright Lecture he made me give him a title before writing the lecture. I therefore had to think of one which would fit any lecture I might conceivably want to give, so that when I came back after Easter I should be able to pick out one of those subjects connected with aeronautics with which I have been specially concerned, and discuss the results arrived at. When, however, I came to sit down to write the lecture itself it struck me that it might be more interesting to a general audience if I followed the line which is perhaps most obviously indicated by my title, and directed my remarks towards tracing and comparing some of the principal lines of argument which have been used in aeronautical research, without going particularly deeply into the results.

In an effort to quantify the feasibility of candidate space architectures for astronauts servicing Geosynchronous Earth Orbit (GEO) satellites, a conceptual assessment of architecture-concept and operations-technology combinations has been performed. The focus has been the development of a system with the capability to transfer payload to and from geostationary orbit. Two primary concepts of operations have been selected: (a) Direct insertion/re-entry (Concept of Operations 1 – CONOP 1); (b) Launch to low-earth orbit at Kennedy Space Center inclination angle with an orbital transfer to/from geostationary orbit (Concept of Operations 2 – CONOP 2). The study concludes that a capsule and de-orbit propulsion module system sized for the geostationary satellite servicing mission is feasible for a direct insertion/re-entry concept of operation CONOP 1. Vehicles sized for CONOP 2 show overall total mass savings when utilising the aero-assisted orbital transfer vehicle de-orbit propulsion module options compared to the pure propulsive baseline cases. Overall, the consideration of technical, operational and cost factors determine if either the aero-assisted orbital transfer vehicle concepts or the re-usable/expendable ascent/de-orbit propulsion modules is the preferred option.

The inclusion of incidence wires in strength calculations, by the method of strain energy, makes very little difference in normal flight conditions, but shows, large changes in wing loads in nose diving and in centre section loads with a broken flying wire. There is a serious increase of load in the bottom plane in nose diving.

I feel deeply honoured to have received the Society's invitation to deliver the 46th Wilbur Wright Memorial Lecture. I undertook the task with humility in the light of the illustrious company who have preceded me but, more particularly, because of the greatness of the contribution of Wilbur Wright whom we honour tonight which, together with that of his brother Orville, continues to provide a tremendous inspiration to all concerned with aeronautics.

In a paper delivered before the Society in March 1960, Morgan concluded that a Mach number of about 2.0 may prove a natural “fit” for the first generation of long-range supersonic transports. Sub-sequently, at the second Congress of I.C.A.S., Kuchemann developed the theme of fitting an aircraft to a particular duty and concluded that the slender wing provides a natural basis for the layout of the supersonic transport. It is convenient to accept these two papers as a starting point for a more detailed examination of the aircraft, since, taken together, they can be taken as fixing some of the major variables—range, speed and general layout.